african journal of environmental economics and management vol. 1 (3), pp. 059-063, october, 2013. available online at www.internationalscholarsjournals.org © international scholars journals review institutionalizing environmental hazards for ‘public needs’: destruction of forest for drinking water supply in kerala, india s. mohammed irshad jamsetji tata centre for disaster management, tata institute of social science, malatil and jal a.d. naoroji (new) campus, sion-trombay road, p. o. box 8313, deonar, mumbai-400 088, india. accepted 20 june, 2013 natural resource exploitation is increasingly being considered as a technical issue with the assumption that it can be compensated for. the public concern shifts towards such destruction only when it affects the normal course of day to day life. immediate needs often undermine the process of institutionalizing knowledge to ensure conservation of natural resources. the question of immediate needs often acts as the determining factor in decision making. this paper is focused on such an environmentally-legal issue in ensuring water availability through the destruction of rain forest. this paper discusses this issue in detail and raises the question of failure of institutionalizing knowledge. key words: sustainability, institutionalizing disasters, beneficiary group, neo-liberalism. introduction this paper is about the socio-environmental relationship in contemporary ecology management. diversion of rain forest for drinking water supply scheme is discussed as a contradiction in environmental governance. pipe water supply services are largely depending on perennial sources of water, especially surface flowing water. fresh water eco-systems are integral parts of surface water and flowing water. the dependencies on perennial sources are also rising. thus, drinking water supply providers are forced to pay less attention on ecology and put more efforts on ensuring water supply. water polices are become incapable to protect the aquatic biodiversity and other vital resources. the ecological impact of freshwater ecosystems is undervalued across the world. this crises put in place certain recommendations, such as equitable market, realistic pricing and protection of ecosystems (johnson et al., 2001). the cost of supplying water supply is generally calculated on the basis of neo-classical economics, which gives thrust on ‘full cost pricing’ based on the ‘user pays’ principle. this cost criterion failed to assess the environmental cost. environmental and social costs are having multiple dimensions and implications are also different (abeysuriya k et al 2008). environmental costs are directly connected with the deterioration of natural assets due to economic activities (united nations, 1997). the natural resources such as streams, rivers, lakes, e-mail: mohammed.irshad@tiss.edu or mohammedirshad31@gmail.com. abbreviations: bg, beneficiary group; wb, world bank; kwa, kerala water authority; o&m, operation and maintenance; krwsa, kerala rural water supply and sanitation agency; seuf, socio economic and unity foundation; jbic, japan bank of international cooperation. irshad 059 enhances its service to society (forestry commission: getting widened across the world. climate change, population and unregulated consumption of freshwater will lead to freshwater crisis in the coming century. sustainable utilisation of freshwater is depends on the changing culture of water management (robert b et al 2002). environmental conservation programmes faces multiple challenged in the developing world due to the dependency on resources (brooks and roumasset 2002). the market process of pure demand management do not just between objects (commodities or inputs) and objective functions (demand, supply, utility, profit), but rather reflect relations between living human beings (zafirovski, 2000). such relation is often challenging the institutions formed to meet the demand and supply. however, the sustainability of institutions is getting public support. institutional understanding of ecology has been de-limited into the sustainability of collective needs rather than ecological equity. this paper discusses this issue with reference to forest vis a via drinking water provision in kerala, india. the paper examines the role of the state in institutionalizing ecological damage in the neo-liberal development governance. this paper attempts to examine the institutional nature of ecological destruction and its consequences on governing environment. the neoclassical economic understanding of ecology and natural resource conservation do not reflect the social, economic and environmental realities of the world. the strongly integrated utilitarian approach to development critically destroy the value system based on ecology and alternatives to protect (anthony m 1992). the paper focuses on the bureaucratic understanding of ecology and the problems of identifying alternatives. this paper is the result of an enquiry on a foreign funded drinking water supply project in kerala, india. the project is called japan bank of international cooperation (jbic) funded urban drinking water supply augmentation programme. one component of the project is to increase the amount of pipe water supply to the urban consumers of kerala water authority (kwa) in thiruvanthapuram district of kerala, india. however, after completing all the infrastructure development, kwa had faced an unparalleled legal hurdle to carry over the project. the hurdle was the availability of water in reservoir situated in one of the rain forests to meet the demand. increasing the dam’s height at the cost of rain forest was the only solution left to augment the water supply. since the reservoir is in the wild life sanctuary across the karamana river, government of kerala had to take the prior consent of the ministry of environment and forest, government of india to increase the dam’s height. this issue has not met with any public criticisms and resistance. this is the motivation of this paper, and the paper tries to raise the following issues. irshad 51 2011). the gap between demand and supply for water a) how does the project influence the environmental governance of the state? b) how are the larger alternative ideas discussed in these types of projects? secondary sources from kerala water authority, discussions with the forest department staffs, kerala water authority staff and members of kani tribal community have been used. sources of water and challenges kerala is well known for its water resources and the state is experiencing severe water scarcity. protections of river resources are highly problematic. the annual rainfall availability is estimated to be about 3000 mm (induchoodan, 1996). however, there is significant variation and a shortage of safe drinking water in many places of the state, besides the availability of average rainfall of 3,055 mm (indian meteorological divisions). ground water availability in kerala kerala has an annual replenishable ground water resource of 7,900 million cubic meters (mcm). the central ground water resource board, kerala division has estimated that the net ground water availability of the state is 6229.04 mcm. according to central ground water board, only 48 per cent of the ground water sources in kerala has been exploited (state planning board, 2003). open wells are major as well as the traditional source of drinking water in kerala; in fact the whole concept of drinking water is still attached to open wells. centre for water resources development and management in 1989 revealed that there were three million wells in the state, of which 20 lakhs were private wells. the density of open wells is also very high in kerala, with density around 250 well per sq.km in the coastal belt; 150 in the midlands and 25 in the highlands. table 1 explains this in detail. surface water availability in kerala kerala has 44 rivers, out of which 41 are west flowing and 3 east flowing. these rivers are characterized as ephemeral; so monsoon rainfall is the main source of survival (james, 2003) (table 2). the annual utilizable yield from 31 rivers is 49,199 mcm (63% of the total), with the state’s share of 87 per cent (42,672). but it has been estimated that the state is utilizing only 25 percent of the annual utilizable yield (state planning board, 2003). though kerala has huge water sources potential, the natural water conservation receives less public attention 060 afr. j. environ. econ. manage. table 1. ground water resource of kerala as on march 2003 km 2 /year. provision for domestic and industrial and other uses 1.31 available ground water resources for irrigation 6.59 net draft 1.46 balance ground water resources for future use 5.13 level of ground water development (%) 22.17 source: central ground water board (2005). table 2. medium river basins of kerala. river basins length (km) catchment area (sq. km) chaliar or baypore 169 2788 periyar sivajini hills 244 5398 pamba devarmalai 176 290 source: central water commission (1999) and ministry of water resources (2004). table 3. destruction of forest areas for developmental projects in kerala (1980-2003) state approved cases during 1980-2003 number of cases area diverted (in hectare) kerala 182 40729.082 india 10358 872791.991 source: department of forests & wildlife, government of kerala. table 4. types of forests in kerala (lakh ha.). forest type area total area (%) tropical wet evergreen forests 3.48 37.02 tropical moist deciduous forests 4.1 43.62 tropical dry deciduous forests 0.094 1 mountain sub tropical 0.188 2 plantations 1.538 16.36 total 9.4 100 source: department of forests & wildlife, government of kerala. and forest protection as well. tables 3 and 4 explain the nature of the forest as well as its destruction. in kerala, big cash crop plantation sector like rubber is considered as forest area. thus, the forest management policy of the state is heavily hinged on the interest of plantation lobby. forest degradation is becoming an order of the day in the state; for instance from 1905 to 1965 forest degradation had been about 0.27% of total geographical area per year; in 1965 to 1973, 1%, from 1972 to 1975, 8611 sq. km, and from 1980 to 1982 is estimated as 7370 sq.km. 3.17% per annum (national average during the period = 2.79%). peppara wildlife sanctuary peppara forest area is one of the 18 ‘biological hot spots’ of the world. peppara sanctuary has great floral and faunal significance; now the number of hot spots is raised to 34. the sanctuary spreads over 53 sq.km of forest which forms the catchment of peppara reservoir. it was declared as a sanctuary in 1983. there are more than 4500 species of flowering plants found in kerala. the sanctuary consists of part of palode reserve (24 sq.kms) and part of kottoor reserve (29sq.kms). the total area of the sanctuary is 53 sq.km. the total water spread of the reservoir is 5.82 sq.km. the sanctuary is located at about 50kms north east of thiruvananthapuram city in nedumangad taluk (kerala state, india); it is between longitude 76°40' and 77°17' east and latitude 80°7'and 8°53' north. the records of kerala forest research institute indicate that there are 145 species of mammals of which 14 species are endemic to western ghats; 169 species of fresh water species; 93 amphibian species of which 40 species are endemic and 486 species of birds, with 16 endemic to western ghats, in addition to innumerable micro-flora and fauna. general topography of the area is hilly with elevation varying from 100 to 1717 m. rainfall and other climate factors are similar to that of neyyar wildlife sanctuary. there are 13 tribal settlements in the sanctuary. eleven are in athirumala section and two are in thodayar section. peppara wild life sanctuary is a part of agasthyamala forest. it is in thiruvananthapuram district of the kerala state, india. the forest types in the area are west coast tropical evergreen, west coast semievergreen, southern hill-top tropical evergreen, southern wet temperature, southern moist mixed deciduous and southern montane grasslands. the biological wealth of these forests is not fully explored. the presence of medicinal herbs is a positive aspect. one of the 7 medicinal plants conservation areas in kerala forests is in the sanctuary. the water supply to thiruvananthapuram city and adjoining sub-urban areas depended exclusively on the perennial streams sprouting from the rain forest of this sanctuary. see table 6 for details of the dam. problems and challenges the major source of pipe water in the area is the karamana river. the total production and demand and irshad 061 table 5. demand and supply of drinking water in thiruvananathapuram. year 2006 2011 2021 2036 demand ml 246 261 294 331 supply ml 151 151 151 151 deficiency 95 110 143 180 source: demand and supply assessment report of thiruvananathapuram. kerala water authority 2005. \ supply gap of drinking water supply in the city are as follows: total production – from major schemes 190 ml miner schemes 28 ml total 218 ml loss due to leakages 67 ml supply 151 ml existing demand 246 ml demand supply gap 95 ml apart from that, table 5 tells us the demandsupply forecast of the city. the aforesaid figure 1 show the increasing demand for augmented drinking water supply in the thiruvananthapuram urban and semi-urban areas. hence increasing the dam’s storage capacity was vital for ensuring adequate supply of drinking water to thiruvananthapuram in the coming years. implications of augmentation of water supply on forest table 6. details of the dam. details of the dam length of dam 438 m height of dam 36.5 m top width 4.0 m gross 70.70 mm3 dead storage 1.6 mm3 live storage 68.5 mm3 hydrology catchment area 60 sq km average rain fall 481.00 cm annual run off at dam site 312.30 million m 3 peak design flood 860 m 3 /second reservoir full reservoir level + 110.50 m minimum draw down level + 85.25 m gross storage 70.00 million m 3 dead storage 1.60 million m 3 live storage at f r l 68.40 million m 3 water spread area at f r l 849.60 hectares attaining the target is not just technical in nature; in order to reach this target, the storage capacity of the peppara dam would augment, which was the sole source of drinking water for thiruvananthapuram. the full reservoir level (fsl) at peppara would go up from104.5 to 110.5 meters. the total water that can be stored in the dam would then go up from 40 million metric cubes to 70 million metric cubes. however, the issue arising here is that the augmentation of the dam’s capacity would result in submerge of 267 hectares of forest land, for which kerala water authority has estimated that compensatory forestation would compensate the rain forest of peppara and it would require $6 million. (this is from the reply for my request under right to information act from kerala dam type general bed level of river at dam site length of dam top height of dam above river bed top width length of spill way elevation of crest of spill way spill way crest gate outlet quantity of concrete concrete straight gravity + 75.50 m 423 m 36.50 m 4.00 m 49.00 m + 104.50 m 4 nos 10 m x 6 m size 1 no of size 1.50 dia 1,80,000 m 3 water authority). legal issue in 1972, the government of india had declared the wildlife (protection) act, according to which “every specified plant or part or derivative thereof shall be the source: peppara dam site property of the state government if there is any offence committed against this act or any rule or order made there-of, and, where such plant or part or derivative thereof has been collected or acquired from a sanctuary or national park declared by the central government, 062 afr. j. environ. econ. manage. figure 1. area of peppara dam. source: broacher of peppara wild life sanctuary. such plant or part or derivative thereof shall be the property of the central government”. in 2002 the government of india had introduced the wildlife protection amendment bill, which did not make any substantial changes in the previous bill but extended the purview of the wildlife protection. new legal task the government of kerala is entrusted to seek the central government’s help to amend the 1972 and 2002 act to augment the dam’s capacity. the state government had made all efforts to get the act amended. delay in getting permission would create a further economic crisis owing to the huge aid from jbic. the project is a package of five water supply schemes approved for loan assistance by the overseas economic cooperation fund (oecf) of japan (now the japan bank for international cooperation) in 1996. the objectives of the project are to supplement and rehabilitate water supply systems of two urban regions namely thiruvanathapuram and kozhikode and to construct water supply systems for three rural regions namely, meenad, cherthala and pattuvam including their adjoining villages. it is the largest ever urban water supply project in the state. the total cost of the project is $ 389 million; government of kerala contributes $ 58.5 million and loan component is $ 331.45 million 1 . the ministry of environment and forest has permitted the kerala water authority to increase the dam’s height in order to augment the water supply. displacement of tribal about 100 kani tribal families were displaced in 1981 as part of peppara dam construction and they were offered 5 acres of land as compensation. there has been no attempt by the government of kerala and kwa to distribute the land. the community settled themselves near the area close to the dam. there are about 13 kani settlements in the reservoir area, of which 7 are within the close vicinity of the reservoir and facing the second phase of displacement. the displacement and livelihood laws of the kani community have not been critically looked into while taking decisions on augmenting the drinking water supply. the study raises the following issue for further discussion. the question is how do we define the ‘water need’ vis a vis forest/ecology? if we pose this question to the society, the likely answer would be in favour of water and not the forest. thus an ecology hardly becomes an issue. providers of water supply (government) and beneficiaries (consumers) are equally responsible for this. thus the following are the likely implications of the issue: 1. the possibility of institutionalising ecological hazards: the forest submerges have been introduced to the public not as an institutional failure but as part of a government’s programme. this new perspective eventually institutionalizes the ecological hazards. 2. lack of public protest: the urban consumers are not raising voice in favour of forest and the kani community’s displacement has not been considered as a social issue. 3. challenges in the long term ecological sustainability: the crucial impact of these types of institutionalizations is that it would undermine the need of long term ecological management in particular. 4. compensatory afforestation: the money offered by kwa to forest department for compensatory forestation needs to be critically looked at. replacing the rain forest in peppara is in fact an ambiguous statement, and indeed there are hardly any models available to justify this argument 2 . 1 loan agreement between government of india and jbic for kerala 2 the chief forest officer said that kwa would give rs 30 crore for compensation and forest department would spend the money through social forestry department. irshad 063 5. lack of search for alternatives: search for alternatives is completely set aside in the project. kwa and jbic units are paying little interest in alternatives such as rainwater harvesting, leakage detection of kwa supply lines. of course this may not be sufficient enough to meet the growing demand for water; however, these alternatives are able to meet the partial demand for household water requirements. nevertheless, the larger impact of this type of project is that it would never allow such alternative to get institutionalised. such institutions get less importance in environmental governance (goldsmith: 1992). acknowledgement ms. meena s nair and ms. usha for supporting the field work and details of tribal displacement. references abeysuriya kcm, juliet w (2008). expanding economic perspectives for sustainability in urban water and sanitation. development 51:23-29. anthony m. (1992) economics, ecology and sustainable development: are they compatible? environ. values 1(2):157-170. brooks k, james r (2002). valuing indirect ecosystem services: the case of tropical watersheds. environ. dev. econom. 7(4):701-714. irshad 55 forestry commission (2011). edinburgh guidelines fourth edition. goldsmith aa (1992). institutions and planned socioeconomic change: four approaches. public admin. rev. 52(6):582-587. induchoodan nc (1996). ecological studies on the sacred groves of kerala, research thesis of pondicherry university. james cj (2003). water management in sooryamoorthy r and antony (eds.). managing water and water users: experience from kerala’s maryland: university press of america. johnson n, carmen r, jaime e (2001). managing water for people and nature science, new series. am. assoc. adv. sci. 292(5519):1071. kerala water authority's demand supply analysis of thiruvanathapuram (2005). prepared by kwa engineers. kerala water authority. p. 1. robert bj, stephen rc, clifford nd, diane mmr (2002). water in a changing world” issues in ecology 9 pp. state planning board (2003). economic review, government of kerala, thiruvanathapuram. kerala. india. wild life protection act, 1972 amended in 2002. ministry of environment and forest, government of india p. 1. zafirovski mz (2000). an alternative sociological perspective on economic value: price formation as a social process' international j. pol. cult. soc. 14(2):265-295. in ternationa l scholars journa ls african journal of environmental economics and management issn 2375-0707 vol. 2 (1), pp. 177-180, january, 2014. available online at www.internationalscholarsjournals.org © international scholars journals author(s) retain the copyright of this article. full length research paper an investigation of zinc uptake by maize plants after fertilization with soil and foliage 1pedro lima*, 1adriana gisele, 2luiz braga ponte and 2alberto santos chico 1 department of environmental science, faculty of agriculture, federal university of amazonas, manaus, amazonas, brazil. 2 department of soil science, faculty of agricultural science, university of the state of amazonas, manaus, amazonas, brazil. accepted 23 january, 2014 zinc is an essential micronutrient for the regular and healthy growth and reproduction of plants, animals and humans and it is obtained from daily dietary intakes therefore, the deficiency of this nutrient is a consequence of its low concentration in food. in this sense, increasing the density and the bioavailability of zn in edible parts of plants is fundamental to produce better crops. the objectives of the study were to investigate the zinc (zn) uptake by maize plants after fertilization with zn either via soil or via foliage. it was carried out a greenhouse pot experiment using a typic hapludox. maize plants were harvested 100 days after seeding and zn concentrations were determined in leaves and roots. the experimental design consisted of five doses of zn applied via soil as well as via foliar, with three replications, totaling 30 experimental samples. zinc was applied as zinc sulfate solution in the foliage at the third and fifth weeks after seeding. the zinc sulfate solution was applied to soil before seeding. the zn concentrations in roots and shoots of plants were analyzed. the results were submitted to anova and regression using the software sas. zinc concentrations in maize were increased at 5% of significance by f test by the application of zn doses in soil and in the foliage. the application in soil was more effective than in the foliage. key words: zn fertilization, zn deficiency, maize yield. introduction zinc is a micronutrient for the regular and healthy growth and reproduction of plants, animals and humans. graham et al. (1992) commented that there is a critical level required for zinc in the soil before roots will either grow into it or to function effectively. the metabolic functions of zinc are influenced by on its strong tendency to form tetrahedral complexes with n-, oand particularly sligands and thereby to play both a functional (catalytic) and a structural role in enzyme reactions. although over 70 metalloenzymes containing zinc have been identified, these only account for a relatively small proportion of the total zinc in a plant (marschner, 1995). when the supply of available zinc for plants is inadequate, crop yields are reduced and the quality of crop products is normally damaged. in plants, zinc plays *corresponding author e-mail:pedrolima@yahoo.com. a key role as a structural constituent or regulatory cofactor of a wide range of different enzymes and proteins in many important biochemical pathways. these are mainly concerned with carbohydrate metabolism, both in photosynthesis and in the conversion of sugars to starch, protein metabolism, auxin (growth regulator) metabolism, pollen formation, the maintenance of the integrity of biological membranes, the resistance to infection by certain pathogens (alloway, 2008). necrosis and leaf chlorosis are described as symptoms of toxicity of zn, and frequently show disturbances in mineral nutrition, such as iron deficiency and reduced uptake and transport of water and several elements (ca, mg, k and mn) by plants (benavides et al., 2005). principles for use of micronutrient fertilizer were well developed in the latter part of the last century. by 1990 it was clear that zn deficiency in humans were already major and still increasing problems, especially in developing countries, but also and enormous health cost pedro et al. 177 in developed countries (graham, 2008). the potential impact of zinc deficiency on infant, child, and maternal health in developing countries was not recognized by the united nations until 1997, when zinc was included among the micronutrient deficiencies listed as a priority in the third report on the world nutrition situation (acc/scn, 1997). zinc supplementation can reduce morbidity from a number of common childhood infections, especially diarrhea, pneumonia, and possibly malaria. in addition, zinc deficiency is an important cause of stunting (umeta et al., 2000). because zn interacts with such a vast number of proteins, symptoms of zn deficiency in humans may be many and indiscriminate, and consequently many disease states are not associated with its deficiency when they should be. (graham, 2008). zn fertilizers increase both the yield and quality of several crops, including wheat (hu et al., 2003; cakmak, 2008), rice (liu et al., 2003), and peas (fawzi et al., 1993). given most brazilian soils present low zn concentrations (gonçalves junior et al., 2006; nascimento et al., 2006), the proper management of zn fertilization can increase the concentrations of zn in plants edible parts. this is of paramount importance for adequate levels of this nutrient in the human diet. plant roots uptake zn as zn 2+ cation which is component of synthetic and organic complexes (havlin et al., 2005; oliveira & nascimento, 2006). the zinc available to plants is in the soil solution or adsorbed in a labile form. the soil factors affecting the availability of zinc to plants control the amount of zinc in the soil solution and its sorption-desorption from/into the soil solution. these factors include: the total zinc concentration, ph, organic matter concentration, clay concentration, calcium carbonate concentration, redox conditions, microbial activity in the rhizosphere, soil moisture status, concentrations of other trace elements, concentrations of macro-nutrients, especially phosphorus, and climate (alloway, 2008). soil ph is the main factor affecting zn distribution in soil pools, since this element is readily adsorbed in exchange cation sites at aboveneutral ph and made available at low ph values (broadley et al., 2007; havlin et al., 2005). taking in account the zn role in plant nutrition as well as the importance of supplying zn to plants in an adequate and cost-effective approach, the work aimed to compare zinc levels in maze plants after two different zn applications to plants, i.e., via foliar and via soil. material and methods the experiment was carried out in a greenhouse using a typic hapludox soil from igarassu town, pernambuco state, brazil (7°50' s and 34°54' w). the soil sample was characterized (embrapa, 1997) and presented the following characteristics: ph h2 o (1:2.5): 5.6; cec: 6.95 cmolc kg -1 ; calcium: 2.45 cmolc kg -1 ; magnesium: 2.05 cmolc kg -1 ; sodium: 0.07 cmolc kg -1 ; potassium: 0.12 cmolc kg -1 ; organic carbon: 1.24%; organic matter: 2.09%; nitrogen: 0.12%; phosphorus: 18.1 mg kg -1 , zinc: 2.48 mg kg -1 , copper: 0,2 mg kg -1 , iron: 172.0 mg kg -1 , manganese: 4.71 mg kg -1 . soil samples were submitted to fertilization as follow: 300 mg kg -1 of p2o5; 40 mg kg -1 of s; 100 mg kg -1 of n; and 150 mg kg -1 of k2o (novais et al, 1991). then, ten liter pots were filled with soil and five seeds of maize (zea mays) hybrids pioneer 30r75 were sown in each pot. after emergence, only one plant was left in each pot for the experiment. zn was foliarly applied as zinc sulfate at the third and fifth week after seeding whereas zinc sulfate was applied into the soil before sowing. the experimental design consisted of five doses of zn applied either to soil or leaves, with three replications, totaling 30 experimental units. zn doses applied to soil were based on the dose recommend by fageria (2000) of 20.0 mg dm -3 as zinc sulfate (23% zn). thus, the applied doses were 0; 10; 20; 40; and 80 mg dm -3 of zn. for foliar application, doses were based on abreu et al. (2007): 10 g l -1 of zinc sulfate (23% zn). therefore, the doses used were 0; 5; 10; 15 and 20 g l -1 of zinc sulfate applied at the third and fifth week after sowing. at the end of the experiment, the height of 100day old plants was measured. the plants were harvested and separated into roots, stems and leaves, which, after being washed in distilled water and dried in an oven of forced air at 70ºc to constant weight, they were weighed and ground in a mill type wiley. subsequently, the nitropercloric digestion of these materials was performed for determination of cu and zn in the extracts by atomic absorption spectrophotometry according to embrapa (1999). the results were submitted to anova and regression analyze using the software sas (sas inst., 2002). results and discussion zinc concentration in roots and shoots of maize plants were increased by zn application both in soil and leaves. regarding the form of application, zn concentrations in roots and shoots showed a similar trend. the highest values were obtained by soil application (figure 1). the highest zn doses promoted the maximum zn concentration in plants both for soil (80 mg dm -3 of zn sulfate) and foliar application (20 g l -1 of zinc sulfate). the 10 mg dm -3 dose applied in soil promoted a 72% increment of zn concentration in shoots (figure 1) while an increase of 67% was obtained with dose 5 g l -1 by foliar application compared to control. zn concentration in roots increased 88% by applying 10 mg dm -3 of zn in soil, whereas the doses 20, 40, and 80 mg dm -3 promoted increments of 38, 34, and 28%, respectively. when applied in the foliage, the 5 g l -1 dose increased by 32% 178 afr. j. environ. econ. manage. [z n ] (m g k g -1 ) 7000,0 6000,0 5000,0 4000,0 3000,0 2000,0 1000,0 0,0 0 shoots roots roots: y = 6,415x + 153,95 r 2 = 0,7729 shoots: y = 26,191x + 139,26 r 2 = 0,9974 20 40 60 80 zn doses (mg dm -3 ) figure 1: zinc concentration in shoots and roots of maize plants fertilized with zinc via soil [z n ] (m g k g -1 ) 1200,0 shoots: y = 43,155x + 169,63 shoots 1000,0 roots r 2 = 0,8228 800,0 600,0 400,0 y = 6,797x + 0,642 200,0 r 2 = 0,6654 0,0 0 5 10 15 20 zn doses (g l -1 ) figure 2 – zinc concentration in shoots and roots of maize plants fertilized with zinc via foliar in roots zn concentration; similarly, the doses 10, 15, and 20 g l -1 of zn promoted increases of 10%, 32% and 66%, respectively. zn concentration in maize plants ranges from 25 to 150 mg kg -1 for shoots, depending on the soil aeration and soil temperature, moisture in the root zone as well as the genetic material (malavolta, 2006). for the highest zn dose applied in soil, zn concentration in shoots was 2,258 mg kg -1 . on the other hand, the higher dose applied in leaves reached 1,186 mg kg -1 in shoots. the increasing trend of zn uptake by plants (figures 1 and 2) indicates that the zn fertilization via soil as well as via foliar can both be adequate strategies to supply of zn to maize plants, since it can be observed that the zn uptake by shoots and roots were increased according to the increment of zn doses. the height of plants presented the highest values for the higher doses for zn applied both in soil and in the foliage (figures 3a and 3b), but the values were more effective when zn doses were applied in soil (figure 3a). adequate supply of zn might also contribute to the enrichment of maize grains, a staple crop responsible for the nutrition of millions of people in the developed countries (allen et al., 2006). although some authors state that the efficiency of foliar application is higher than ground fertilization (malavolta, 2006), the zn uptake by roots was more effective in this study. a study carried out by amiri et al (2008) also presented this trend in apple, which foliar application of zn resulted in decreasing fruit yield and quality. several chemical (soil ph, redox potential or nutrient interactions), physical (organic matter content, soil texture, or clay content and type) and biological factors (mycorrhizae formation, phytosiderophore release) operating at the root–soil interface may affect availability and absorption of zinc and subsequently, zinc efficiency (hacisalihoglu and kochian, 2003). conclusions both the foliar and soil fertilization were efficient for increasing zn concentration in maize plants and also pedro et al. 179 90 (c m ) 85 h e ig h t 80 75 70 0 90 85 (c m ) 80 75 h e ig h t 70 65 60 0 (a) y = 0,1685x + 74,985 r 2 = 0,8525 20 40 60 80 zn doses (mg dm -3 ) (b) y = 0,898x + 67,48 r 2 = 0,9673 5 10 15 20 zn doses (g l -1 ) figure 3 – height of maize plants fertilized with zinc via soil (a) and via foliar (b). contributed for their growth. the highest values of zn concentration in plants were observed when zn was applied via soil. acknowledgements this research was sponsored by fundação de amparo à ciência e tecnologia do estado de pernambuco (facepe) and by conselho nacional de desenvolvimento científico e tecnológico (cnpq). references abreu ca, lopes as, santos g (2007). micronutrientes. in: novais rf, alvarez vh, barros nf, fontes rlf, cantarutti rb, neves jcl (eds.). fertilidade do solo. viçosa: sociedade brasileira de ciência do solo, 645-736. acc/scn. administrative committee on coordination/sub-committee on nutrition. third report on the world nutrition situation. geneva: world health organization, 1997. allen l, benoist b, dary o, hurrel r (ed.) (2006). guidelines on food fortification with micronutrients. geneva: who/fao – world health organization and food and agriculture organization of the united nations. available at: www.who.int/bookorders/anglais/detart1.jsp?sesslan=1&codlan=1&c odcol=93&codcch=215. accessed in10 mar 2008. alloway bj (2008). zinc in soils and plant nutrition. brussels, belgium and paris, france: iza and ifa. pp. 139. amiri me, fallahi e, golchin a (2008). influence of foliar and ground fertilization on yield, fruit quality, and soil, leaf and fruit mineral nutrients in apple. j. plant nutr. 31: 515-525. benavides mp, gallego sm, tomaro ml (2005) cadmium toxicity in plants. braz. j. plant physiol. 17:21-34. broadley mr, white pj, zelko i, lux a (2007) zinc in plants. new phytol. 173: 677-702. cakmak i (2008) enrichment of cereal grains with zinc: agronomic or genetic biofortification? plant soil, 302: 1–17. embrapa (empresa brasileira de pesquisa agropecuária) (1997). manual de métodos de análise de solo. 2. ed. rio de janeiro, centro nacional de pesquisa de solos. pp. 212. embrapa. empresa brasileira de pesquisa agropecuária (1999). manual de análises químicas de solos, plantas e fertilizantes. brasília: embrapa comunicação para transferência de tecnologia. pp. 370. fageria nk. (2000) níveis adequados e tóxicos de zinco na produção de arroz, feijão, milho, soja e trigo em solo de cerrado. revista agriambi, 4(3): 390-395. fawzi afa, ei-fouly mm, moubarak zm (1993). the need of grain legumes for iron, manganese and zinc fertilization under egyptian soil conditions: effect and uptake of metalosates. j. plant nutr.. 16: 813– 823. gonçalves jr ac, prestes al, ribeiro ol, santos al, santos (2006). métodos extratores e fitodisponibilidade de zinco para milho em argissolo vermelho-amarelo eutrófico. sci. agrária. 7: 35-40. graham r, archer js, hynes sc (1992) selecting zinc-efficient cereal genotypes for soils of low zinc status. plant and soil. 146: 241-250. graham rd (2008). micronutrient deficiencies in crops and their global significance. in: alloway bj (ed.) micronutrient deficiencies in global crop production. springer: german. pp.353. hacisalihoglu g, kochian l (2003). how do some plants tolerate low levels of soil zinc? mechanisms of zinc efficiency in crop plants. new phytol. 159 (2):341-350. havlin jl, beaton jd, tisdale sl, nelson wl (2005). soil fertility and fertilizers. new jersey: pearson. pp.515. hu yx, qu cg, yu jn (2003) zn and fe fertilizers effects on wheat 180 afr. j. environ. econ. manage. output. chinese germplasm. 2: 25–28. liu j, li k, xu j, liang j, lu x, yang j, zhu q (2003). interaction of cd and five mineral nutrients for uptake and accumulation in different rice cultivars and genotypes. field crops res. 83(3): 271-281. malavolta e (2006). manual de nutrição mineral de plantas. são paulo: agronômica ceres, 638p. marschner h (1995). mineral nutrition of higher plants. london: academic press. pp. 889. nascimento cwa, oliveira ab, ribeiro mr, melo eec (2006). distribution and availability of zinc and cooper in benchmark soils of brazil. commun in soil sci and plant analysis, 37: 109-125. novais rf, neves jcl, barros nf (1991). ensaio em ambiente controlado. in: oliveira aj, garrido we, araújo jd, lourenço s (coord). métodos de pesquisa em fertilidade do solo. brasília: embrapa-sea. pp. 189-253. oliveira ab, nascimento cwa (2006) formas de manganês e ferro em solos de referência de pernambuco. revista brasileira de ciência do solo. 30(1): 99-110. sas inst. (2002) sas/stat user’s guide. version 8.2 for windows. sas inst., cary. umeta m, west ce, haidar j, deurenberg p, hautvast pjg (2000). zinc supplementation and stunted infants in ethiopia: a randomised controlled trial. lancet, 355: 2021-2026. african journal of environmental economics and management vol. 1 (1), pp. 022-027, august, 2013. available online at www.internationalscholarsjournals.org © international scholars journals full length research paper environmental port management: conceptual model development and use of tools to evaluate and monitor dredging activities in the port of rio grande, brazil j. ronaldo torres* and l. antônio philomena fundação universidade do rio grande, departamento de ciências morfo-biológicas. caixa-postal 474, rio grande, cep 96.201-900, rs brazil. accepted 2 may, 2013 this work concerns assessing and monitoring of dredging activities in the port of rio grande, brazil. the subject is presented to address the major problems related to the dredging process itself and sediment disposal options. from the dredging works carried out in 1998, 2000 and 2003 on the port of rio grande, different data were gathered and used to develop a preliminary conceptual model of this process. the conceptual model elaborated and presented in this study consists of technical, ecological and socio-economic aspects of dredging. this model, which is an analysis of the major points to be considered when dealing with dredging projects at the port of rio grande, highlights the importance of monitoring these activities from all aspects. the main points to be considered are: selecting the type of dredge and the method of management and disposal of the sediments; monitoring the impacts within the environment (plants, animals, water and sediment quality), and the operational and monitoring costs of these activities. another point that should be considered is about the disposal options or beneficial reuse of the dredged material. key words: brazil, dredging, environmental impacts, modeling, monitoring. introduction one important research field in developed and developing countries is the improvement of ports and channels by the use of dredging activities. these activities produce a certain level of impacts and a monitoring program should always be considered to evaluate their environmental consequences. most of the ports worldwide have been established in rivers, estuaries and lagoons in highly populated industrial centers. the navigation channels in the entrance of these ports and estuaries suffer shoaling processes requiring frequent dredging to maintain their depth. however, the sediments present at the bottom of industrialized ports are usually contaminated with trace metals and organic compounds. thus, the dredged material must be carefully handled and disposed at proper sites. therefore, dredging activities demand correct planning and decision making on the process itself, as well as on the handling *corresponding author. e-mail: rjtorres2000@yahoo.com.br. and disposal of the dredged material. in developing countries such as brazil, there is a lack of information related to dredging works (torres and calliari, 2004). in many cases, existing information are not presented to the community, being held by the port administration they belong to or research institutes that do not publish them. in a worse situation, very few of the ports and channels that require dredging have any kind of environmental monitoring and evaluation program. the first brazilian legislation dealing with the dredging process was approved in march, 2004 and addressed the characterization of the sediment in order to decide the disposal options in coastal areas and monitoring the disposal site, with several physical, chemical and ecotoxicological parameters (conama, 2004). environmental impacts associated to the dredging process and spoil disposal can be characterized by direct effects over organisms and habitats and indirect effects attributed to alterations in water quality (kennish, 1994, 1996). physical disturbances associated to removal and re-location of sediments are considered direct effects and torres and antônio 022 provoke the destruction of benthic habitats, increasing mortality of these organisms. indirect effects are associated with the resuspension of bottom sediments with remobilization of contaminants and nutrients affecting the water quality and the increase of turbidity and decrease on the conditions of light dispersion. according to davis et al. (1990) and bray et al. (1997), the impacts of dredging can be divided into several categories: 1. dispersion and deposition of resuspended sediments; 2. depth alterations; 3. effects and changes in coastline configurations; 4. loss of habitats on bottom sediments and water column, as well as fishing resources; 5. noise; 6. odor and 7. changes in overall environmental quality (both in the dredging site and disposal site). environmental monitoring, by definition, consists on making specific measurements and observations of some indicators and parameters with the purpose of verifying if the required environmental impacts are happening, their intensity and to help choose and evaluate which mitigating procedures can be taken (araújo, 2006). in the case of dredging operations, the variables to be monitored according to iadc/ceda (1998) and usepa (1998) are related to depth control, suspended sediments generation, spill generation, density in the pipeline and/or disposal site, physical and chemical characteristics and biological parameters. therefore, there is a need to develop monitoring techniques of these activities aiming to align projects in accordance with the existing policy, which can be complemented by international laws on dredging and disposal. the evaluation of the techniques used in projects around the world could help in implementing mechanisms that better represent the reality of the brazilian ports (fredette and french, 2004). the multidisciplinarity involved in dredging activities which include port, naval and ocean engineering, oceanographic processes (comprising physical, chemical, geological and biological oceanography) and environmental, ecological, economical, social and legal aspects to which the dredging operations are closely related must be considered in designing a monitoring program. the objective of this work is to present an overview of the dredging activity in the port of rio grande and develop a conceptual model giving emphasis on aspects that should be considered in the management of a dredging activity, from the environmental, technical and socio-economical point of view. also, from this conceptual model, some tools for the environmental monitoring process of the activity can be commented. materials and methods study area the port of rio grande is the southernmost port of brazil (figure 1) and is located at the west margin of the north channel (considered the natural drainage of the patos lagoon hydrographic basin). its geographic location and the extent of protected waters make it ideal for the flow of commerce from the rio grande state and the north of argentina, presenting great importance to the economy of the region. it is the third most important brazilian port, after the ports of santos and rio de janeiro (torres, 2000). the city of rio grande is locate in the margins of the estuarine region of the patos lagoon, in a peninsula limited to the south and northeast by shallow bays ("saco da mangueira, saco do martins and saco do justino"); to the north by the north channel; and to the east by the access channel to the patos lagoon and the atlantic ocean ("canal do rio grande"; figure 1). the estuarine region is located between the latitudes of 31°30's and 32°30's and longitudes 51°55'w and 52°15'w and consists of the transition area that has some influence from salt water and the fresher lagoon waters. the patos lagoon estuary is classified as a coastal plain estuary or bar estuary according to fairbridge (1980) (in hartmann, 1996). kjerfve (1994) also denotes this estuary as choked (strangled) because it is a narrow and long lagoon, composed of elliptic cells connected with each other and with a long and narrow channel linking to the ocean. with the increasing importance of the port of rio grande, the improvements on the navigation conditions of the patos lagoon inlet took place with the construction of the "molhes da barra" (two 2 mile long jetties at the entrance of the lagoon). this construction, which started in 1898 and finished in 1915, is one of the biggest coastal engineering works in brazil. these jetties fixed the bar, allowing a natural deepening of the channel from 2.5 to 6 m. lately, with the dredging works to open the rio grande canal, in 1972, ships with a greater draft were able to enter the estuary. the main periodic dredging every two to three years (hartmann, 1996). mainly suspended matter is a major contributor makes up of the sediments contribution to in the patos lagoon and estuarine area. baisch (1994) estimated that the solid discharge from the guaíba system and camaquã river are about 5.3 million meter cube per year, of which about 82% is from the guaíba and 18% from the camaquã. according to this author, only 25% of this volume reaches the estuarine region, or a total of 1.2 million meter cube. adding to the total is the amount of sediment exported from the mirim lagoon through the são gonçalo channel, this volume comes to about 2 million meter cube of suspended matter all contributing to the shoaling process in the navigation channels. according to the available data, maintenance dredging of the rio grande port is about 1.4 million cubic meters per year, divided in three distinct areas: rio grande canal, approximately 1,040,000 m 3 /year; access channel to porto novo, 75,000 m 3 /year, and; evolution basin of porto novo, 285,000 m 3 /year (portobrás, 1979). model development the dredging operation in the port of rio grande that took place from march to august 1998 was accompanied and previously evaluated biological, physical, chemical and geological characteristics of the area such as biological and hydrological cycles, water and sediment quality and socio-economical aspects of the region present in torres (2000) were gathered in order to develop a conceptual model based on energy fluxes according to odum (1971, 1994) regarding environmental, technical and socioeconomic aspects as well as the information on the techniques that is normally used in dredging projects. this model comprises the sources of energy (represented by the objects outside the dashed rectangles), the pathways of the energy inside and across each different compartment and the final destination of this energy. to help evaluate and refine this model, the two subsequent dredging projects (in 2000/2001 and 2003/ 023 afr. j. environ. econ. manage. figure 1. rio grande region map showing the port areas, the navigation channels and the disposal site used until 1998 and the current site [modified from hartmann (1996)]. 2004) and their environmental monitoring programs were analyzed. results and discussion the total amount dredged from rio grande port in the 1998 dredging operation was approximately 2,940,000 m 3 in the three sections of the port that was dredged (rio grande channel, access channel to porto novo and evolution basin of porto novo). the disposal site was located offshore, in front of the mar grosso beach in são josé do norte rio grande's neighbor town about 5 nautical miles from the east jetty, at a depth of about 13 m. this disposal site was considered unsuitable because it could form sand bars in the beach area, affecting the incidence of waves in the foundation of the east jetty, and it could cause its rupture (calliari and tagliani, 1997). this problem was avoided during the 2000/2001 and later dredging operations on which another disposal site started to be used, located about 13 miles offshore with an approximate depth of 20 m (figure 1) and out of the navigation routes as proposed by torres (2000). it is known from prior projects that the sediments from depth of this channel is about 14 m and is maintained through rio grande channel are contaminated by trace torres and antônio 024 figure 2. schematic (conceptual) model presenting the relationship between the various processes related to the dredging activities. metals and organic contaminants from the port area, from the effluents of the industries based in the industrial district, especially from the fertilizer industries and from the adjacent sewage effluent from the city (baisch, 1997). as dredging re-suspends this sediment allowing these contaminants to get back to the water column, it is advisable that these activities should be monitored before, during and after the operations are concluded. the schematic model shown in figure 2 was developed by observation of the dredging operation that took place in 1998. as an ecological model, it was based on the energy circuit language designed by odum (1971, 1994). it takes into account the following major aspects: environmental/ ecological, technical and socio-economic aspects which are represented by dashed line rectangles. the linkages and relationships between the different compartments of the model can be used to generate information on the design of new dredging projects. this conceptual model can be used to identify which points of the dredging process can be optimized and the model gives a background for future studies on dredging operations of the rio grande port and estuarine area, as well as other ports in the brazilian coast. as such, it represents a comprehensive system representation of cause and effects. the model is designed in order to organize information into a comprehensive representation of the system’s important structure (components) and function (processes) and cause-and-effect relationships. the model components and relationships may be used to assess and evaluate changes to the system and effects of management actions, alternatives, and scenarios on the system and system structure and function. since most dredging projects are site specific, this conceptual model can be used to identify which points of the dredging process can be optimized and gives a background for future studies on the dredging operations of the rio grande port and estuarine area, perhaps it may be adapted and used as bases for other dredging projects in brazil and other places around the world. the main points to be considered are: selecting the type of dredge and the method of management and disposal of the sediments; how to make a monitoring plan of the impacts over the environment (plants, animals, water and sediment quality), and the operational costs and monitoring costs of these activities. one aspect that should be emphasized is the volume to be dredged at specific sites, which in many cases can be influenced by geological and climatic cycles of the region, raising or reducing the volume of sediments that reach the estuarine area. another point that should be considered is the choice of disposal options or reuse of the dredged material. some of the techniques used can be dangerous to the environment and human health while others can be beneficial such as the use of these sediments for beach nourishment, landfill or construction material. a pilot project has been conducted in order to reuse the sediments from the area of porto novo as material for blocks and cement to be used as construction material (dias et al., 2004). according to asmus and zamboni (2001) and asmus et al., (2002), the impacts of the 2000/2001 dredging works on benthic organisms, plankton, fish and fishing resources, vegetation, water and sediment quality, and the overflow activity (discharge of the exceeding water from the interior of the hopper dredge, and which contains fine grained sediments), were monitored in the dredging site and at the disposal site for the first time in the maintenance dredging that happened in the years 2000/2001. from this monitoring activity, it was possible to determine that dredging should be done on the periods that the outflow regime from the patos lagoon can carry the re-suspended sediments to the ocean, preventing it to re-settle in the channel. also, as sediments were contami-nated with trace metals and organic compounds, it required careful management and placement. the main toxic compounds were persistent organic pollutants (pops), sulfur and nitrogen from the city sewage outlets and phosphorus (p), lead (pb), copper (cu), cadmium (cd), zinc (zn), chromium (cr) and nickel (ni) from the fertilizer industries on the industrial district adjacent to the port area. pops were not quantified, but some of these metals such as cu, pb and zn have shown violations of the sediment quality guideline called erl (effects range low), which might present toxic responses to living organisms (long et al., 1995). some of these compounds may bioaccumulate in seafood resources, representing some potential harm to human health. the environmental effects to plants and animals of the estuarine area of the lagoon and nearby coastal zone mainly result from the increase of turbidity, with normal concentration of about 50 mgl -1 of suspended sediments reaching up to 15,000 mgl -1 in the plume behind the hopper dredge, which represents a reduction in light incidence and reflects on the plant growth and fisheries life cycles. also, sediment settlement in the channel and disposal site can affect benthic organisms, suffocating them. during the dredging work of 2003/2004, a monitoring program was also conducted (asmus and granato, 2004). in this particular project, the overflow was controlled. this way, the suspended particles in the plume behind the dredge did not reach the same values as on the previous dredging, remaining below the 500 mgl -1 level, even though it is still above safe levels. also, another action that was taken was related to conducting most of the work during the periods when the discharge from the lagoon to the ocean was larger, pushing the turbidity plume to the sea and preventing the settlement of the sediments back in the channel and estuarine region. this proved to be a good practice to improve the overall conditions of the estuarine and marine area. tools for monitoring dredging activities in the last few decades, a great number of studies regard-ing environmental impacts of dredging have been con-ducted (fredette and french, 2004). some of them in europe, asia and north america discuss the importance of assessing sediment quality and how it is related to environmental toxicology (usepa, 1998). some of these tools for monitoring dredging activities (also known as lines of evidence or loe) have been characterized as follows: physical and chemical characterization: grain size, total organic carbon (toc), acid volatile sulfides and simultaneously extracted metals (avs/sem), metal speciation and persistent organic pollutants such as polycyclic aromatic hydrocarbons (pahs), polychlorinated biphenyls (pcbs) and some pesticides (cesar, 2006; lotufo, 2006); biological characterization: ecotoxicological assays with whole sediments, water from the interface watersediment, interstitial water and elutriates, use of microtox ® , histopathology and mutagenicity, evaluation of benthic community structure and bioaccumulation of chemicals by fish and invertebrates (cesar, 2006; sáfadi, 2006; umbuzeiro, 2006). summary and recommendations from the information obtained, it was possible to draw the following conclusions and recommendations for future dredging projects and other scientific works regarding dredging and environmental management: 1. the knowledge of natural and anthropogenic shoaling processes of estuarine areas and navigation channels is the first step to understand what happens in the port area. 2. good assessment of the magnitude of contaminants present in the sediments from the bottom of the channels is necessary in order to prepare safe actions for the 025 afr. j. environ. econ. manage. torres and antônio 026 dredging activity and spoil disposal, especially for the fact that dredging can re-mobilize these contaminants. 3. in the port of rio grande, the dredging works should be conducted during periods of water discharge from the lagoon so the re-suspended sediment would be carried out of the estuary. in other ports, the hydrodynamic system of the estuary should be evaluated in order to understand what happens with fine sediments and what would be the best option to reduce recontamination of the estuary. 4. monitoring the quality of water and sediments as well as the influence of the dredging operations on the biological, chemical and physical processes on the estuarine and marine areas should be conducted before, during and after the dredging work takes place. 5. dredging activity management should comprise the aspects presented in the conceptual model proposed here and includes the choice of dredging equipment and the best disposal techniques, evaluation of the volume to be dredged, assessment of water and sediment quality, as well as the biological cycles in the port area 6. a model enhancement and testing with data to be collected in new dredging projects may generate hypotheses about uncertain relationships or interactions between components which may be tested and revisions made to the model through an adaptive process; 7. according to recent studies (césar, 2006; lotufo, 2006), some tools for monitoring dredging activities are necessary. these tools are related to physical and chemical characterization as well as biological and ecotoxicological evaluations. these aspects are foreseen on the recent brazilian legislation conama 344/04 that concerns about the assessment and monitoring of dredging activities in brazilian jurisdictional waters, which is under evaluation. the conceptual model conceived in this work is important for communication and decisionmaking that incorporates different disciplines and a range of affected stakeholder and agency groups involved in the dredging activity in brazil. acknowledgement authors would like to thank cnpq – brazilian national council for the development of science and technology for an m. sc. scholarship given to the first author. references araújo n (2006). curso de avaliação de impacto ambiental (course of environmental impact assessment). pró-ambiente assessoria ambiental. p. 46. asmus ml, granato fc (2004). relatório técnico referente às atividades desenvolvidas no monitoramento ambiental da operação de dragagem no canal de acesso ao porto de rio grande. 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(mutagenesis bioassays: real tendencies and use as tools for monitoring). i workshop sobre ferramentas para o monitoramento das atividades de dragagem (i workshop on tools for monitoring dredging activities). 19 de outubro. são paulo. united states environmental protection agency (usepa) (1998). evaluation of dredged material proposed for discharge in waters of the u.s. – testing manual. usepa/usace epa-823-b-98-004. p. 176. in ternationa l scholars journa ls african journal of environmental economics and management issn 2375-0707 vol. 3 (1), pp. 210-217, january, 2015. available online at www.internationalscholarsjournals.org © international scholars journals author(s) retain the copyright of this article. full length research paper a study of the development of vegetation type map using visual image interpretation technique shankar patel1, acharya patnaik1, omkar sanjeev ashok2 and gulati goyal goswami2 1 department of crop improvement, faculty of agricultural sciences, lingaya's university, faridabad, haryana, india. 2 school of natural resource management, indian agricultural research institute, pusa, delhi, india. accepted 02 october 2014 rajasthan, the largest state of india has a geographic area of 342,239 km 2 ; shows great variation in climate and vegetation. in the present study, vegetation types and land use of rajasthan were mapped using multi-season irs p6 liss iii data. visual image interpretation technique was adopted in mapping the heterogeneity of land cover classes at 1:50,000 scale. georeferenced phytosociological information was also used to delineate different vegetation formations. altogether 26 vegetation type classes were mapped in the study region. the vegetation cover occupies 16.78% of the geographical area of the state. of the total vegetation cover, forest area is contributing 4.71% of the geographical area. the main forest types of rajasthan includes dry deciduous forest, thorn forest, broad leaved hill forest, dhauk forest, teak mixed forest and riverine forest. the vegetation type map prepared provides a key input for biodiversity understanding at landscape level. keywords: remote sensing, rajasthan, visual interpretation, vegetation types. introduction the vegetation is one of the invaluable natural resources which changes spatio-temporally in its extent and distribution. hence, reliable information on the extent and distribution of vegetation types is pre-requisite for natural resource management and planning. more recently, knowledge of the vegetation types is becoming increasingly critical to assess and monitor the potential vulnerability of natural ecosystems due to human induced global environment change. the difficulty of mapping spatial pattern in vegetation types largely depends on the level and scale of biodiversity under investigation. in this direction, the use of remote sensing and geographic information systems (gis) for mapping vegetation systems has proved helpful and expanded considerably in recent years (madden, 2004). remote sensing technologies offer various tools which can detect, map, and monitor the natural resources ranging from global to micro levels. mapping scale and spatial resolution are the most important parameters to evaluate when selecting satellite remote sensing data. if vegetation mapping is from regional scale to continental *corresponding author email: shankar_patel@gmail.com scale modis and avhrr satellite image data with pixel sizes ranging from 250m to 1,000 m are found to be appropriate. many global initiatives, such as modis land cover estimation, food and agriculture organization (fao) assessments, global land cover facility (glcf) give estimation of forest cover with coarse resolution data which may not fulfill the requirement of planners and ecologists (hansen et al., 2000; lotsch et al., 2003). but for mapping and identification of habitats with different mixed vegetation types, single species dominated systems, locale specific formations and degraded types, the spatial resolution of 20-30 m are more appropriate; and thus, important for landscape scale studies of vegetation mapping (singh et al., 2002). vegetation mapping utilizes both qualitative and quantitative data collection techniques in order to create a database containing the spatial location and attribute table information of the plants (hasmadi et al., 2009). mapping of vegetation types with sole use of digital image classification techniques and single season satellite data is difficult in tropical forests. a common problem is that the varied land cover formations and illumination angle changes over small areas may result in spectral confusion. also, the human disturbance and edaphic conditions induces seral vegetation stages and locale specific types which can create spectral confusion shankar et al. 210 (helmer, 2000). as the vegetation types in tropical part of india represents diverse formations, on screen visual image interpretation approach was found to be suitable to delineate various vegetation types (singh et al., 2005; reddy et al., 2008; reddy et al., 2009). in the present study, irs p6 liss iii data which is having spatial resolution 23.5 m was used to generate baseline information of vegetation types of rajasthan, india. the objective of the present study was to develop detailed vegetation type map using visual image interpretation technique supplemented by information collected from phytosociological surveys. study area rajasthan is the largest state in india, occupying an area of about 3,42,239 km 2 nearly about 11 percent of the total geographical area (tga) of india, and lies between 23º30´ and 30º 12’ north latitude and 69º 30’ and 78º 17’ east longitude. rajasthan is bordered by pakistan in the west and northwest, the indian states of punjab, uttar pradesh and haryana lie in the north and northeast, madhya pradesh in the southeast and gujarat in the southwest. administratively, rajasthan is divided into 33 districts (ajmer, alwar, banswara, baran, barmer, bharatpur, bhilwara, bikaner, bundi, chittorgarh, churu, dausa, dholpur, dungarpur, hanumangarh, jaipur, jaisalmer, jalore, jhalawar, jhunjhunu, jodhpur, karauli, kota , nagaur, pali, pratapgarh, rajsamand, sawai madhopur, sikar, sirohi, sri ganganagar, tonk and udaipur). rajasthan is a unique state which shows great variation from one area to another and is noticeable in respect of climate, altitude and vegetation. rajasthan has three major physiographic regions, viz. the western desert (thar desert), the aravalli hills and the southeastern plateau. the most striking geographical feature is the aravalli range the oldest folded mountain range in the world, which intersects the state diagonally end to end north-east to south-west into three-fifth north-western desertic zone and two-fifth eastern semi-arid region. the elevation of aravalli range gradually decreases in northeast direction, as it is 1,772 m at mt. abu (gurushikar), 1100 m at bijapur, 913 m at harshanath and 792 m at khetri; the elevation further decreases to 335 m at delhi beyond the boundaries of the state in north-east direction. the total forest area of the state is 16,036 km 2 , which occupies 4.69% of the total geographical area (fsi, 2009). the population of the rajasthan is 56.61 million (census, 2001). the state experiences varied climatic conditions ranging from extreme aridity in the northwestern parts (jaisalmer) to sub-humid conditions in the southern parts (jhalawar, banswara and mount abu). however, most of the state (94%) falls under arid and semi-arid conditions with low and erratic rainfall patterns. pre-monsoon season , the hottest period, extends from april to june with temperatures ranging from 32 o c to 45 o c. the winter season is from january to march and temperature may drop to 0 o c in some cities of rajasthan, such as churu. materials and methods the entire state of rajasthan has been covered in 36 scenes of irs p6 liss iii data. the multi-season data was chosen for optimal discrimination of various vegetation types. ortho-rectified landsat etm+ datasets were downloaded from glcf website (http://glcf.umiacs.umd.edu/). all the scenes were acquired and geometrically corrected with reference to landsat etm+ satellite data. the planimetric accuracy standards of ≤ 1 pixel error were achieved for all the scenes. the false colour composite (fcc) mosaic of irsp6 liss-iii data for the entire state of rajasthan is shown in figure 1. landsat etm+ (2001) and irs p6 awifs (2008) datasets were also used for reference. the ancillary data of survey of india toposheets on 1:50,000 scale and spatial datasets of elevation data (from shuttle radar topography mission), dcw (digital chart of world), village location and road network was used in the study. classification scheme the vegetation delineation depends on spatial, spectral and temporal resolution of the satellite sensor on one hand and the spatial extent and degree of homogeneity of the species assemblages on the other hand. the forest class is subdivided into mixed species forest types, gregarious species forest types, locale specific types, degraded types based on composition and location specific distribution controlled by physiographic, edaphic and disturbance conditions. the sub classification under these classes was made based on phenology, physiognomy and dominant compositional patterns following the principles of indian forest type classification developed by champion and seth (1968). grasslands are primarily classified based on climatic, edaphic and species associations. the classification scheme of dabadghao and shankarnarayan (1973) was utilised with certain modifications. visual interpretation of the vegetation types was carried out and different classes were interpreted using on screen digitization method. the interpreted product was further collaborated with ground truth information and phytosociological data. the interpreted vector layers of each district were mosaiced and the edge contrast and other inconsistencies were harmonized. likewise, for all the 33 districts of rajasthan, vegetation type maps were prepared on 1:50,000 scale. the vegetation type map of rajasthan thus prepared is estimated to have an overall mapping accuracy of 89%. field study field surveys were undertaken to get acquainted with the general patterns of vegetation types of the study area. major vegetation types and important localities of characteristic types were recorded. the variation and tonal patterns were observed on irs p6 liss iii images. stratified random sampling in the various vegetation types, further helps in classifying them up to community level. phytosociological sample plot data of 1800 points were utilized in the study. to facilitate the on-screen visual interpretation, some site-specific vegetation types were identified and image chips were extracted from corresponding irs p6 liss-iii scenes. all the unique image templates along with field information and photographs were made as geospatially referenced database for figure 1. irs p6 liss-iii false colour composite image of rajasthan delineating similar such areas across the entire scene. the image templates were also evaluated across the scenes for the degree of conformity and to maintain uniformity across the scenes. results in rajasthan, natural vegetation cover occupies 16.78% of the total geographical area (figure 2, table 1). among the five forest systems mapped at level 1, mixed formations occupy 79.22% of forest area followed by gregarious formations of 12.98%, degraded formations (3.68%) and forest plantations (3.50%) (figure 3). the vegetation type map clearly showed that 4.71% of the geographical area is under forest cover. the major forest types delineated in the state are broad leaved hill, dry deciduous, dhauk forest, thorn, teak mixed, riverine forest, tree/shrub savannah and forest plantation. scrub and grasslands occupy significant area and represented with 9.18% and 2.87% of geographical area respectively. broad leaved hill forest occupies 80.25 km 2 and unique to mount abu wildlife sanctuary of sirohi district. of the deciduous systems, mixed dry deciduous forest is dominant and occupies 10,443.81 km 2 followed by anogeissus pendula edgew. (1354.13 km 2 ) and teak (456.03 km 2 ). of the thorn vegetation system, mixed thorn forest represents 2252.16 km 2 followed by acacia senegal (l.) willd. (212.19 km 2 ) and prosopis cineraria (l.) druce (72.12 km 2 ). riverine forest is a locale specific vegetation type accounted for an area of 99.69 km 2 . being located in arid and semi-arid zone of india, rajasthan represents low area (4768.84 km 2 ) under water bodies (including wetlands) and which occupies 1.39% of total geographical area. agriculture is predominant land use in rajasthan estimated as 250123.15 km 2 (73.08%) of 211 afr. j. environ. econ. manage. shankar et al. 212 figure 2. vegetation type and land use map of rajasthan geographical area. discussion the important vegetation types of rajasthan were discussed below: broad leaved hill forests: broad leaved hill forests (central indian subtropical hill forests (8a/c3) as per champion and seth, 1968) of rajasthan shows a mixture of evergreen and deciduous tree species. it is dominated by mangifera indica l., anogeissus sericea brandis., anogeissus lalifolia (roxb. ex dc.) well. ex guill. and perr., lannea coromandelica (houtt) merr. and syzygium cumini (l.) skeels. total area covered by this forest is 80.25 km 2 (0.02% of total geographical area). there is a more of dry vegetation, which in its present form resembles dense dry deciduous forest though representing evergreen elements. the steep slopes mark table 1. areal extent of vegetation types and land use of rajasthan (area in km 2 ) sl.no. class area (km 2 ) area (%) a forest i mixed formations 1 broad leaved hill forest 80.25 0.02 2 dry deciduous forest 10448.62 3.05 3 thorn forest 2252.16 0.66 sub total 12781.04 3.73 ii gregarious formations 4 dhauk forest (anogeissus pendula edgew.) 1354.13 0.40 5 teak mixed forest 456.03 0.13 6 acacia senegal (l.) willd 212.19 0.06 7 prosopis cineraria (l.) druce. 72.12 0.02 sub total 2094.48 0.61 iii locale specific formations 8 riverine forest 99.69 0.03 sub total 99.69 0.03 iv degraded formations/woodland 9 tree savannah 468.44 0.14 10 shrub savannah 125.07 0.04 sub total 593.52 0.17 v forest plantation 11 mixed plantation 564.89 0.17 sub total 564.89 0.17 b/vi scrub/shrubland 12 thorn scrub 4788.36 1.40 13 dry deciduous scrub 12440.38 3.63 14 euphorbia scrub 130.68 0.04 15 prosopis juliflora (swartz.) dc.scrub 92.44 0.03 16 desert dune scrub 13958.24 4.08 17 lantana scrub 8.26 0.002 18 calotropis scrub 4.77 0.001 19 ravine scrub 48.47 0.01 sub total 31471.61 9.20 c/vii grassland 20 saline grassland 25.36 0.01 21 swampy grassland 2.80 0.001 22 lasiurus-panicum grassland 3339.45 0.98 23 cenchrus-dactyloctenium grassland 5430.01 1.59 24 aristida-oropetium grassland 80.15 0.02 213 afr. j. environ. econ. manage. shankar et al. 214 table 1 cont. 25 sehima-apluda grassland 667.28 0.19 26 aristida-dichanthium grassland 283.59 0.08 sub total 9828.64 2.87 d/viii orchards 321.11 0.09 e/ix agriculture 250123.15 73.08 f/x water bodies 4685.00 1.37 g/xi wetlands 83.84 0.02 h/xii long fallow/barren land 26439.93 7.73 i/xiii settlement 3152.17 0.92 grand total 342239 100 figure 3. pie chart showing distribution of level 1 forest categories this terrain evident from other surroundings. image shows these areas as bright tone with rough texture in both seasons. dry deciduous forest: it is equivalent to northern dry mixed deciduous forests (5b/c2). this forest type shows prominence of anogeissus pendula edgew. (popularly known as dhauk), butea monosperma (lam.) taub, lannea coromandelica (houtt) merr, boswellia serrata roxb ex coleb, anogeissus lalifolia (roxb. ex dc.) well. ex guill. and perr. and diospyros melanoxylon roxb. dry deciduous forests (tropical dry deciduous forests according to champion and seth, 1968) occupy major proportion under natural vegetation cover and predominantly found in udaipur, rajsamand, ajmer, kota, baran, chittorgarh districts. it occurs at an altitude of around 200-600 mts. it is spreading over an area of 10,448.62 km 2 (3.05% of tga). in green season satellite image dry deciduous forest looks dark red in tone with rough texture, but in dry season the areas take up greenish shade with no evidence of foliage. background reflectance of dry/often burnt undergrowth marks this system. contiguity of these forests over large areas is common and can be generally found interspersed with contrasting fringing forests in dry season. dhauk forest (anogeissus pendula edgew.): it is edaphic climax forest (6/e1) as per champion and seth' classifcation (1968). this type is largely determined by the anogeissus pendula which forms nearly pure crops, often well stocked, about 6 m. height. these forests are predominantly found in northern aravallis, central aravallis and east of aravallis. profuse growth of anogeissus pendula also found in kumbalgarh wildlife sanctuary in southern aravallis. it is leafless from february june. the associated species are those of dry deciduous forests. the rainfall ranges between 500-900 mm. area covered by this type is 1354.13 km 2 . when browsing pressure is heavy the anogeissus pendula is reduced to spreading and creeping forms. teak mixed forest: it is known as dry teak forest (5a/c1b) according to champion and seth' s classification. teak mixed dry deciduous forests are found in southern region of rajasthan dungarpur and banswara districts. area covered by this type is 456.03 km 2 (0.13% of tga) the species composition in this type includes tectona grandis l., anogeissus lalifolia (roxb. ex dc.) well. ex guill. and perr., butea monosperma (lam.) taub., diospyros melanoxylon roxb., lannea coromandelica (houtt) merr and boswellia serrata roxb ex coleb. on satellite image it gives appearance of dark brown tone with rough texture in december image but it gets mixed up with dry deciduous forest in dry season. one of the most characteristic features regarding association is the contiguous tracts prevailing in foot hills and on low altitude hills of the plateau. relatively intense ground truthing is essential for confirmation, in spite of its characteristic smoky looking dry deciduous tone at places. thorn forest: it is equivalent to northern tropical thorn forests (6b). thorn forest are mostly found in thar desert and central aravallis of rajasthan. common species in this type are prosopis cineraria (l.) druce., acacia senegal (l.) willd, acacia nilotica (l.) willd. ex del, acacia leucophloea (roxb.) willd., acacia tortilis (forssk.) hyene.and zizyphus mauritiana lam. etc. capparis decidua (forssk.) edgew.is indicator species of thorn forests in western rajasthan. there is a less admixture of dry deciduous forest species as compared to its counter part of southern tropical thorn forests of peninsular india (champion and seth, 1968). on image it gives a rough texture with light to dark tone in both dry and wet season image. acacia senegal (l.) willd forest: it is the edaphic type of thorn forest (6/e2) with acacia senegal and few associated species like acacia leucophloea (roxb.) willd. and zizyphus nummularia (burm.f.) wight. and arn. it is distributed in desert region and aravallis. prosopis cineraria (l.) druce forest: it is a desert thorn forest (6b/c1) with extremely open crops of scattered trees. the delineation of prosopis cineraria forest is subjective and based on the field knowledge and technical skills due to scattered trees here and there. riverine (riparian) forest: these are referred as dry tropical riverain forests (5/1s1) in champion and seth's classification. riverine forests are interspersed in deciduous systems, wherever streams and rivers flow as surface channel over longer periods than surroundings. these areas are narrow strips along the hilly intersections of the large streams. the species constituting such forests include syzygium heyneanum (duthi.) wall.ex gamble, terminalia arjuna (dc.) wight and arn., syzygium cumini (l.) skeels., holoptelea integrifolia (roxb.) planchon., ficus racemosa l. almost near perfect contrasts are apparent during dry seasons on image. image shows these areas as bright tone in both seasons. woodland: it was referred as dry savannah forest (5/ds2) in champion and seth's classification. depending on the mode of degradation, fire/grazing/edaphic conditions, the forest shows deterioration and becomes woodland. based on the severity of disturbance, woodland of two types were common in aravallis of rajasthan and they are referred as tree savannah and shrub savannah. tree savanna differs from shrub savanna only in tree height and spacing. tree savannah appears dark maroon with pinkish tinge tone and have medium to coarse texture. shrub savannah presents light maroon with cyan tinge tone and possess medium to coarse texture. scrub: scrub is a vegetation cover predominantly occupied by shrubs or poor tree growth chiefly of small or stunted trees with crown density less than 10%. it is the first most dominant vegetation class covering an area of 31,471.61 km 2 . desert dune scrub occupies 13,958.24 km 2 is unique to sandy parts of desert on partially stabilised dunes and on shifting dunes. it is the dominant scrub type of rajasthan. thorn scrub is generally seen in the fringes of thorn forests, hill tops and nearby settlements. dry deciduous scrub has been subjected to more degradation and frequently found in and around dry deciduous forests. calotropis scrub is specifically found in long fallow areas and bordering crop fields in desert region. euphorbia scrub is unique to rocky and badly eroded areas of both desert and aravallis. it is a very open formation in which euphorbia caducifolia haines. predominates. prosopis juliflora (swartz.) dc. and lantana camara l. are worst invasive alien species and threat to native biodiversity (reddy, 2008). prosopis juliflora and lantana camara being aggressive colonizers, form dense thickets referred as prosopis scrub and lantana scrub, respectively. prosopis juliflora often grows along road sides, canals and degraded thorn forest lands and rapidly spreading in desert and aravallis. lantana camara prefers openings and fringes of dry deciduous forests and subhumid tracts of broad leaved hill forests. grasslands: grasslands of rajasthan have been grouped into seven types. all these grasslands are mapped based on habitat information, physical location and unique associations. smooth texture less expanse 215 afr. j. environ. econ. manage. shankar et al. 216 restricted to arid and semi-arid plains and hill slopes mark the land cover. occasionally tree/shrub savannah is associated in the fringes of grasslands. it may mix with barren areas if single season data is used, though for an experienced interpreter the association induced distinction is hard to ignore. lasiurus scindicus-panicum turgidum grasslands are climax vegetation systems adapted to very low rainfall (<250mm) areas of thar desert. cenchrusdactyloctenium grasslands are very common throughout the central and eastern part of rajasthan desert. this grassland receives annual rainfall of 300mm to 500mm and situated in elevation range of 150m-400m. cenchrusdactyloctenium grassland shows dominance of both grass (cenchrus biflorus roxb., dactyloctenium scindicum boiss., aristida adscensionis l.) and non grass species (farsetia hamiltonii royle., crotalaria burhia buch.-ham. ex benth., tribulus terrestris l., tephrosia purpurea (l.) pers, aerva persica (burm. f.) merr., indigofera cordifolia heyne ex roth). it was distributed throughout central and eastern part of rajasthan desert. aristida-oropetium grasslands are edaphically adapted to rocky gravelly plains of jodhpur, ajmer and sikar districts. it is very low productive grassland in terms of biomass and species diversity. sehima-apluda grassland system is unique to aravallis. sehima nervosum is abundant in southern aravallis at an elevation range of 500m-800m. it is inconspicuous in central aravallis. aristida-dichanthium grasslands are prevalent in northern aravallis and eastern part of aravallis. heteropogon contortus (l.) p.beauv., aristida spp (aristida hystrix l., aristida adscensionis l. and aristida funiculata trin.and rupr.) and dichanthium pertusum (l.) clayton. shows widespread distribution throughout aravallis. chrysopogon fulvus (spreng.) chiov. is the common grass species in east of aravallis and locally abundant in ranthambore tiger reserve. saline grasslands are locale specific vegetation systems occuring only in saline tracts of sambhar lake, didwana lake and pachpadra. swampy grasslands (vetiveria-saccharum) are found among the marshes and fringes of wetlands in bharatpur bird sanctuary. other non vegetation classes: orchards includes the fruit plants cultivated along with the agricultural field. orchards were mostly concentrated in eastern districts of rajasthan. current crop lands and current fallow lands were mapped under single class –agriculture. most of the land use area in rajasthan is under agriculture (73.08% of tga), as this is the main occupation of people. there are about 66 crops were grown in the state (http://www.rajasthanonline.in). wheat, barley, jowar, pulses, mustard, maize, bajra are the principal crops. operational estimation systems are in place elsewhere to derive single or multiple cropping areas from satellite remote sensing. along with this other classes mapped were sand, water, settlement, barren land and wetland, which have relatively far better distinction and ease of interpretation as far as the accuracy for the current scheme was considered. visual interpretation procedure help to tide over conspicuous digital processing glitch like confusion between cases of scrub, barren lands, settlements, water and wetlands and alike. conclusions the study demonstrated that remote sensing is a state of the art technological tool to map and distinguish the complex vegetation formations in india. the geospatial data generated on vegetation type maps are prime input for landscape ecological analysis. spatial extent and distribution of vegetation types can be linked to the human induced changes and biodiversity characterisation. acknowledgements authors are thankful to dr. v. jayaraman, director, nrsc, dr. p.s. roy, associate director, nrsc and dr. m.s.r. murthy, head, forestry and ecology division, nrsc, hyderabad for suggestions and encouragement. the present work is carried out as part of project on 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agric. fores. pp.193200. eds. p.c. trivedi. aavishkar publishers, jaipur, india. singh tp, singh s, roy ps, rao bsp (2002). vegetation mapping and characterization in west siang district of arunachal pradesh, india – a satellite remote sensing-based approach. curr. sci. 83(10): 12211230. singh s, singh tp, srivastava g (2005). vegetation cover type mapping in mouling national park in arunachal pradesh, eastern himalayasan integrated geospatial approach. photonirvachak 33(4): 547-563. african journal of environmental economics and management vol. 1 (4), pp. 113-119, november, 2013. available online at www.internationalscholarsjournals.org © international scholars journals full length research paper mixed culture (shrimps, oysters and macroalgae) to improve the productivity, and reduce the environmental impact to coastal ecosystem caused by shrimp hatcheries in mexico guillermo galindo reyes facultad de ciencias del mar, universidad autonoma de sinaloa, paseo claussen, s/n, mazatlan, sin. c.p. 82000. mexico. email: guillermo_galindo_reyes@hotmail.com. tel/fax: +52 669 9828656. accepted 19 august 2013 in mexico, shrimp hatcheries have been developed as intensive monocultures, resulting in hatcheries management troubles, economic losses and environmental impact. therefore, the aim of this work was compare to a traditional culture vs. a mixed culture. shrimp juveniles were distributed in aquariums and ponds at the same density (51 shrimps/m 2 ) but ponds, also had oysters and macroalgae. shrimps in aquaria and ponds were feed with same food amount. water was change each two days, but in ponds only 20%. to compare traditional vs. mixed culture, shrimp’s growth, feed efficiency conversion and nutrients concentration, in aquariums and ponds were recorded. at experiment’s end, shrimps grew 35% more in ponds than aquariums; feed efficiency conversion was 0.68 units lower in ponds than aquariums, and nh4 concentrations were close to 3 and 1 mg/l in aquariums and ponds respectively. the mean increase weight in oyster and macroalgae, was 4.04 and 19.3 g respectively. therefore, mixed culture has many ecological and economic advantages over traditional culture. therefore it is suggested that scaling this technology to commercial level, in addition to shrimps, oysters and macroalgae are produced, which could be used for human consumption and animal fodder respectively. also, this model improves water quality and reduces the environmental impact. key words: shrimp-monoculture, mixed-culture, oysters, macroalgae, higher productivity, water quality, environmental impact. introduction in many countries, the aquaculture activities have grown vertiginously during the last decades. the shrimp cultivation in ponds under controlled conditions is one of most important of these activities (fao, 2008); however, this biotechnology has been developed with many failures, because it is based on not ecological principles, such as intensive monoculture which have resulting with many troubles in the hatcheries management, economic losses and also an increasing environmental impact due to deforestation of mangroves and salt marshes, and excess of organic matter, nutrients and pollutants drained to coastal ecosystems, where the hatcheries are located (primavera, 1998; trott and alongi, 2000). the shrimp world production is not available because there are no data of many producer countries; however, the shrimp importation by the principal regions or reyes 263 reyes 113 table 1. principal importers of shrimp in the world. the product is frozen (with or without head). year 2006 2007 2008 2009 2010 2011 total (m. ton) 727945 732022 700960 693667 697139 738878 japan 115000 116000 105000 102000 115000 110000 e. union 370000 370000 310000 370000 380000 390000 usa 242945 246022 285960 221667 202139 238878 (source: www.goblefish.org/shrimp-december-2011.html). figure 1. typical shrimp hatcheries in the nw coast of mexico (source: google.ca/imgres q=shrimp+hatcheries+in+mexico). countries in the world, is shown in table 1, which give an idea of shrimp’s world production during 2011. mexico held the sixth place in the world as shrimp producer after china, india, ecuador, thailand and others asiatic countries (conapesca, 2011). as currency income, the shrimp fishery is the most important in the country; this yielded $10860 millions of mexican pesos in 2009; approximately $868.8 millions of usd (inegi, 2009). this fishery grew around 13000 metric ton per year from 2003 to 2011 (conapesca, 2011). in 2009, the production reached 181000 metric ton. the same source, report that for each metric ton, 671 kg are produced in hatcheries and 329 kg are fishing in estuaries, coastal lagoons and adjacent sea; therefore, 67.1% of production corresponds to aquaculture. however, all the hatcheries are located in the coastal ecosystems, i.e estuaries, salt marshes and coastal lagoons (figure 1). in nw of mexico, sonora and sinaloa are the states (provinces), which produce 71.6% of shrimp in the county (figure 2). the shrimp aquaculture has been expanding rapidly in these states, but due to “successful”, shrimp hatcheries also are settling in the baja california peninsula (dewalt et al., 2002). the number of producers nearly doubled in the period between 1993 and 2010 to nearly 600 farms; there are now nearly 20,000 ha of shrimp aquaculture ponds in the region; and the average yields are approximately 1.34 tons per hectare (conapesca, 2011). however, only 460 to 480 are in operation; the others are closed due to diverse troubles (dr. audelo naranjo, facultad de ciencias del mar, universidad autonoma de sinaloa, personal communication). such as has seen in other countries, the shrimp aquaculture in mexico has far developed largely with some detrimental environmental effects (mckinnon et al., 2002). considerable evidence of mangrove destruction has been reported. there are no official data, but some authors have reported that mangroves and salt marshes in the sinaloa coast are disappearing at rate of 2 to 3% annually (martínez– córdova et al., 1998; boyd and gautier, 2000; páezosuna, 2001). but the most serious potential threat from shrimp aquaculture in mexico, is the impacts at water quality (dewalt et al., 2002). some authors have reported that detrimental water quality drained into coastal ecosystems is due to high amount of organic matter, high nutrient concentration (particularly nh4, by their toxicity), increased level of coliform bacteria, organic pollutants such as antibiotics, pesticides and in some cases heavy metals (páez-osuna et al., 1999; trott and alongi, 2000; galindo et al., 2008; martínez-córdova et al., 2009). many of these compounds comes from excess of supplied food for fast grow shrimp, which is required by 114 afr. j. environ. econ. manage. figure 2. states of mexico where are located the major number of shrimp hatcheries in the country (adapted from google earth, satellite image). high density of shrimps per square meter in the ponds (30-55 in intensive hatcheries; 80-200 in super intensive hatcheries), excess use of antibiotics, and biocides to combat shrimp diseases, pollution by diesel and oil used for water pumps and blowers, abandoned batteries, etc. (boyd and gautier, 2000; dewalt et al., 2002). faced with this problem, the objective of this work is the implementation of mixed cultures, which in addition to shrimp, contemplates use of filter feeders such as oysters (crassostrea spp.) and cultivation of macro-algae (ulva spp.) known as "sea lettuce" in the effluent of shrimp ponds, or in the same pond. this could reduce particulate organic matter, bacterial load, nutrients excess and some biocides. in other words, this shrimp's productive model, will seems closer to coastal ecosystem, where energy and material fluxes, are not altered excessively; therefore, the ecosystem keeps his homeostasis, reducing environmental impact and increasing the shrimp productivity. materials and methods certificated shrimp larvae (litopenaeus vannamei) were obtained from a commercial larvae producer. the larvae were maintained in an aquarium (18-21°c, 28 psu salinity, 5.5-7.1 ml/l dissolved o2). as food, brine eggs were supplied four times per day during one month, until the larvae reached the juvenile stage (mean weight 0.72 g, mean size 49 mm) then, shrimp juveniles were transferred to three aquariums (0.43 m 2 , 68 l) 66 juveniles per aquarium. the aquariums water was changed each two days, aeration was permanent and physical-chemical parameter (ph, salinity, dissolved oxygen, temperature, and total suspended solids) were recorded, using a hanna® multiparameter apparatus, model hi 9828. the nutrients concentrations were quantified following the protocols presented by (strickland and parsons, 1972). brand food (camaronina) purina ® was supplied two times per day at rate of 12% total biomass (11-12 g/day). in order to keep the aquaria at similar conditions, the shrimp number per aquaria was maintained equal; so dead shrimps were replaced immediately. at the same time, oysters crassostrea corteziensis (mean weight 8.2 g, mean size 37.5 mm) and macro-algae ulva spp. (68 g) were put into three plastic ponds (0.78 m 2 , 240 l); the oyster’s number per pond was 46. the source and conditions of water in ponds were same as in aquaria, but no food was supplied, because no shrimps there were. also water was changed each two days, but only 20% total volume (48 l/pond). the same physical–chemical parameters were recorded, and dead oysters were replaced. when shrimps reached 1.9 g (mean weight) and 61 mm (mean size), they were redistributed into aquariums and ponds (three each), 22 shrimp per aquarium and 40 per pond; therefore, shrimp density was same in each (51 shrimps/m 2 ). in order to compare traditional shrimp culture (aquariums) vs. mixed culture (ponds), the growth rate, the feed efficiency conversion and the nutrients concentration in water, both in aquariums as in ponds were recorded. during this experimentation time, same routine works were performed; that is, water change each 2 days, record of physical-chemical parameters, etc. also, due to shrimp’s growth, the supply of food in aquariums and ponds was increased to 13 to 13.5 g/day; and the amount of macroalgae was increased to 159 g per pond. shrimp mortality was recorded each day, and three weeks after, the experiment was finished. statistical analysis all physical-chemical parameters, chemical analyses and growth parameters were realized by triplicate. a statistical program mystad ® was used to obtain the mean and standard deviation for each variables group and an anova with the shapiro-wilk test for normality and fisher test for homoscedasticity, to calculate the significance values (p). results during first part of this work (january 8 to february 18), there were no relevant changes; just a “normal” growth of shrimps in aquariums. the increase mean weight was 0.63 g (from 0.09 to 0.72), with a standard deviation (s.d.) of 0.05, and in length 43 mm (from 4-7 to 49 mm), with a s.d. of 2.5. the mean growth of oysters in ponds was 1.87 g (from 8.2 to 10.07), with a s.d. of 1.15, and in length 3.9 mm (from 37.5 to 41.4) with a s.d. of 3.1 during the same period. the physical-chemical parameters in ponds and aquariums do not presented relevant differences, except dissolved oxygen and ph, which were significant lower in aquaria than in ponds (table 2). the p-values ranged from 0.000 to 0.024 for dissolved oxygen, and from 0.002 to 0.031 for ph. the values of physical-chemical parameters during the second part of experiment (march 5 to march 28) are summarized in table 3. no significant differences between aquariums and ponds were observed for physical-chemical parameters, except for ph and dissolved oxygen, which were significant higher in ponds than aquariums (p-values ranged from 0.000 to 0.029 for dissolved oxygen, and from 0.007 to 0.035 for ph). the total suspended particles (tss) were moderately higher reyes 265 reyes 115 table 2. physical–chemical parameters during first part of experiment (january 8 to february 18). the ponds had only oyster and macroalgaea; the aquaria just shrimps. data aquarium or pond salinity (psu) dis o2 (ml/l) temp (°c) ph tss( ppb) jan./8/2012 pond 1 28 7.4 19 7.7 19500 jan./8/2012 pond 2 28 7.2 19 7.5 18987 jan./8/2012 pond 3 28 7.3 19 7.7 19500 jan./8/2012 aquarium 1 28 4.2 19 7.3 17510 jan./8/2012 aquarium 2 28 3.9 19 7.3 17680 jan./8/2012 aquarium 3 28 5.4 19 7.4 17670 feb./8/2012 pond 1 28 7.6 21 7.8 18763 feb./8/2012 pond 2 28 7.5 21 7.7 19001 feb./8/2012 pond 3 28 7.4 21 7.8 18720 feb./8/2012 aquarium 1 28 3.2 21 7.2 18010 feb./8/2012 aquarium 2 28 3.2 21 7.2 18000 feb./8/2012 aquarium 3 28 3.1 21 7.1 18480 feb./18/2012 pond 1 28 7.4 19 7.7 19206 feb./18/2012 pond 2 28 7.4 19 7.5 19259 feb./18/2012 pond 3 28 7.5 19 7.5 18760 feb./18/2012 aquarium 1 28 4.7 19 7.3 17530 feb./18/2012 aquarium 2 28 4.7 19 7.3 17880 feb./18/2012 aquarium 3 28 5.1 19 7.4 18000 table 3. physical-chemical parameters during second part of experiment (march 5 to march 28). the ponds had oyster, macroalgae and shrimps; the aquaria just shrimps. data aquarium or pond salinity (psu) dissolved o2 (ml/l) temp (°c) ph tss (ppb) march/5/2012 pond 1 28 7.1 20 7.8 22897 march/5/2012 pond 2 28 7 20 7.5 23065 march/5/2012 pond 3 28 7.2 20 7.6 23110 march/5/2012 aquarium 1 28 4.9 20 7.4 17550 march/5/2012 aquarium 2 28 4.3 20 7.4 21100 march/5/2012 aquarium 3 28 4.1 20 7.5 19970 march/12/2012 pond 1 29 6.9 21 7.7 22659 march/12/2012 pond 2 29 6.2 21 7.5 22920 march/12/2012 pond 3 29 6.5 21 7.4 19760 march/12/2012 aquarium 1 29 4.9 21 7.2 19310 march/12/2012 aquarium 2 29 4.3 21 7.2 19500 march/12/2012 aquarium 3 29 4.3 21 7.2 18720 march/18/2012 pond 1 28 6.8 21 7.7 22789 march/18/2012 pond 2 28 6.9 21 7.8 23100 march/18/2012 pond 3 28 6.9 21 7.5 22986 march/18/2012 aquarium 1 28 4.9 21 7.2 21970 march/18/2012 aquarium 2 28 4.6 21 7.2 21900 march/18/2012 aquarium 3 28 4.5 21 7.3 21890 march/24/2012 pond 1 28 6.4 20 7.6 22765 march/24/2012 pond 2 28 6.5 20 7.6 22500 march/24/2012 pond 3 28 6.4 20 7.5 21900 march/24/2012 aquarium 1 28 4.5 20 7.3 19500 march/24/2012 aquarium 2 28 4.4 20 7.2 21400 march/24/2012 aquarium 3 28 4.1 20 7.2 18740 march/28/2012 pond 1 28 6.4 20 7.7 22234 march/28/2012 pond 2 28 6.2 20 7.8 22750 table 3. contd. march/28/2012 pond 3 28 6.3 20 7.5 21010 march/28/2012 aquarium 1 28 5.7 20 7.3 19120 march/28/2012 aquarium 2 28 5.5 20 7.2 19210 march/28/2012 aquarium 3 28 5.1 20 7.3 20600 figure 3. differences in weight increase of shrimp (mean values) between traditional culture and mixed culture (p-values were 0.041, 0.001 and 0.000 for march 5, 18 and 28 respectively). in ponds than in aquariums; however, the significance values (p) were of 0.057, 0.005 and 0.029 for march 5, 18 and 28 respectively. however, during second part of experiment important differences were registered between traditional cultures (aquaria) vs. mixed culture (ponds), which becomes the relevant points of this work. figure 3 shows the differences in mean weight increase of shrimps between mixed culture and the traditional one. as can be observed, the values were significant higher in ponds than in aquariums, even though food supplied was the same in both cultures, and the shrimp number per aquarium was 22, whereas in ponds 40 in each one. therefore, at the end of experiment, with same amount of food, the shrimps gained 35% more weight in ponds than in aquariums [(3.87g w. in ponds/2.86 g w. in aquariums) ×100-100]; which means an economy of 35% in food supplied. also the feed conversion factor, which is relationship between the amount of food supplied divided by the biomass increase of shrimp, was significantly lower in the mixed culture than in traditional one (figure 4). at the end of experiment, this difference was 0.68 units or 44.7% lower in ponds than aquariums. this means that shrimps have higher metabolic efficiency in pond than in aquariums, or have others food sources, or both; which also becomes an economy of food supplied. in fact, as it was indicated above, the tss were moderately higher in ponds than in aquariums during second part of experiment. as can be observed in table 3, the tss in ponds, ranged from 19760 to 23110, whereas in aquariums, the values ranged from 17550 to 21970; this means a moderately higher organic matter amount in ponds than in aquariums, particularly at the end of experiment. regarding oysters and macroalgae; at the end of experiment, oyster mortality was 14%, leaving about 39 oysters per pond. the final mean size of oysters was 47.1 mm, with a s.d. of 3.59, and the mean weight 14.11 g with a s.d. of 1.35. therefore in a period of 37 days (from february 20 to march 28) the mean increase weight was 4.04 g (from 10.07 to 14.11) and the increase of size 5.7 mm (from 41.4 to 47.1). the algae biomass also had a mean increase weigh of 19.3 g (from 159 to 178.3) per pond with a s.d. of 4.25, during same period. concerning to nutrient concentrations; the ammonia was the nitrogen compound which registered significant differences between aquariums and ponds (figure 5). as observe, at all times ammonia concentrations were significant higher in the aquariums than in ponds. the ammonia in ponds was almost unchanged, also the differences were greater toward end of experiment when the macroalgae biomass was higher in ponds. the nitrate concentrations in water are shown in figure 6. contrary to ammonia values, the differences of nitrate concentration between aquariums and ponds were not significant, however, as the experiment progressed, the nitrates increased both in aquariums as in ponds. the phosphate concentration in aquariums and ponds are shown in the figure 7. as can be observed there are not significant differences between aquariums and ponds, except at march 5. however, the phosphates increased moderately in ponds as experiment progressed, whereas in aquariums were almost unchanged. the n/p relationship found in this work ranged from 4.15 to 17.45 in aquariums and from 8.7 to 13.96 in ponds. discussion from the results obtained, it is possible to reach the 116 afr. j. environ. econ. manage. 1.4 1.2 fa c to r 1 c o n v e rs io n 0.8 0.6 fe e d o f 0.4 m e a n 0.2 0 march march march 5/2012 18/2012 28/2012 m e a n v a lu e s o f n o 3 c o n c . (m g / l ) 0.45 0.4 0.35 0.3 0.25 0.2 0.15 0.1 0.05 0 march march march differences between aquaria (yellow bars) and ponds (blue bars) figure 4. differences in feed conversion factor (mean values) between traditional culture and mixed culture (p-values were 0.037, 0.014 and 0.008 for march 5, 18 and 28 respectively). 3.5 3 l ) c o n c . (m g / 2.5 2 4 n h o f 1.5 v a lu e s m e a n 1 0.5 0 march march march 5/2012 18/2012 28/2012 differences between aquaria (yellow bars) and ponds (blue bars) figure 5. differences in ammonia concentrations (mean values) between aquariums and ponds, during the second part of experiment (p-values were 0.023, 0.005 and 0.000 for march 5, 18 and 28 respectively). 5/2012 18/2012 28/2012 differences between aquaria (yellow bars) and ponds (blue bars) figure 6. differences in nitrate concentrations (mean values) between aquariums and ponds, during the second part of experiment (p≥0.076), except at march 28 (p=0.000). 0.035 0.03 l ) c o n c . (m g / 0.025 0.02 4 p o o f 0.015 v a lu e s 0.01 m e a n 0.005 0 march march march 5/2012 18/2012 28/2012 differences between aquaria (yellow bars) and ponds (blue bars) figure 7. differences in phosphate concentrations (mean values) between aquariums and ponds, during the second part of experiment. (p≥0.062), except at march 5 (p=0.000). reyes 117 118 afr. j. environ. econ. manage. following conclusions and relevant points about the advantages of mixed culture (ponds) over traditional one (aquariums). 1. the growth rate of shrimps was higher in the mixed culture than in the traditional one (figure 3) because the shrimps reached a higher weight in ponds than in aquariums during the same period of time, and with the same amount of food supplied. this means that shrimps in the ponds must have others sources of food, such as phytoplankton and detritus which are not available or are not in the same amounts in the aquariums. this becomes an important issue, because in the commercial shrimp hatcheries, the reduction in the growth time is an important thing, because the production costs becomes reduced as the growth period also is reduced. others authors claims similar conclusions (martínez-córdova et al., 1997). 2. the feed conversion factor also is higher in the mixed culture than in the traditional one (figure 4). this indicates that the efficiency of food assimilation (metabolic efficiency) is higher in ponds than in aquariums, which means an economy of food supplied; therefore in money in the commercial hatcheries, because in the mixed culture the food supplied was 35% less than in the traditional one. 3. the total amount of water changed, was 30% less in ponds than in aquariums; because in the ponds, was 144 l (48 l/pond) each two days, whereas in aquariums was 204 l(68 l/ aquarium) in the same time period. this means an economy in water consumption, which is a very important point because in commercial shrimp hatcheries, the water is pumped from the sea or estuaries toward the ponds; therefore, the energy consumption (electricity or diesel) will be 30% less in the mixed culture than in the traditional one. 4. concerning to ammonium concentrations in water, the values registered in this work, were into the “normal” ranges. other authors report similar concentrations in ponds of shrimp hatcheries (arencibia, 1996; páezosuna et al., 1999, 2001; pis et al., 2010; pereira et al., 2011). common values in semi-intensive shrimp hatcheries, are from 0.1 to 2 mg/l, and in the intensive cultures, values are close to 4 (boyd and tucker, 1998) however, the same authors claims that when ammonia concentration increase, it can create problems in the shrimps, such as low growth and more susceptibility to diseases. in this work the ammonia concentration reached concentrations close to 3 mg/l in aquariums, whereas in the ponds, maximum values were around 1 mg/l (figure 5). this could be attributed to macroalgae, which are consuming this nutrient for growth; therefore, the elevated ammonia concentration recorded in the aquariums, which is a deleterious factor for the shrimp, is not a problem in ponds, consequently, the mixed culture is much more successful that traditional one. although there were not significant differences in nitrate concentrations between aquariums and ponds during the experiment, the nitrate values are slightly higher compared to those reported by pis et al. (2010) and pereira et al. (2011). this could be due to several factors; one of these, are the intense nitrification processes, because at high o2 concentration and ph values greater 7.5, which were recorded in ponds (table 3), the nitrosomas bacteria reduce nh4 to nitrites, and then, nitrites are oxidized to nitrates by nitrobacteria (boyd and tucker, 1998). other important factor is the production/consumption relationship, which is higher in the first part of experiment than in the second one, because in the second one, the consumers are more (phytoplankton, macroalgae, etc.). during the second part of experiment, the biomass of macroalgae was increased from 159 to 178.3 g. conclusions the phosphorous concentrations found in this work, are within normal ranges. other authors report similar phosphorus concentrations in commercial shrimp hatcheries (jackson et al., 2003; lacerda et al., 2006). also, the n/p relationship found, are within ranges reported by jones et al. (2001) and alonso-rodriguez and páez-osuna, 2003) however, the n/p relationship in ponds (mixed culture), are closer to 15, which correspond to coastal waters less disturbed. this suggest that metabolism and recycling of nutrients by bacteria are more efficient in mixed culture than in traditional culture, because the nutrients in shrimp hatcheries comes from food supplied and recycling (briggs and funge–smith, 1994; páez-osuna et al., 1997). from the above comments, we can conclude that mixed culture has many advantages over the traditional one; not only on the production efficiency and economy aspects, but also on the improvement in water quality. on the other hand, with the same amounts of water and food, we obtained a good growth of oysters and macroalgae. this represents a plus in the productivity, because the oysters can be edible after a simple treatment to clean up them; and the macroalgae can be used as animal fodder. other authors propose to use macroalgae, to reduce the eutrophication in effluents of shrimp culture (primavera, 1998; mckinnon et al., 2002). finally, we could demonstrate, at laboratory level, that mixed culture of shrimp (ponds) has many ecological and economic advantages over the traditional culture (aquariums). so, we suggest scaling this technological model of shrimp production to commercial level, in order to replace the obsolete traditional model, improve the water quality, and reduce environmental impact on coastal ecosystems. acknowledgments author wish to thank: programa internacional de becas reyes 119 para la educación superior-sep, and programa de movilidad del consorcio de universidades mexicanas; also to universidad autónoma de sinaloa (uas), by the economic support to performing this project, and to prof. frederic guichard, from mcgill university by his support in this work. also thanks to the students of faculty of marine sciences (uas) by their support in the field and laboratory works of this project. references 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http://www.veterinaria.org/revistas/redvet/n03032010.html primavera jh (1998). tropical shrimp farming and its sustainability. in: s. desilva (ed.), tropical mariculture. academic press, london, pp. 257–289. strickland jdh, parsons tr (1972). a practical handbook of seawater analysis. fisheries research board of canada, ottawa. bulletin 167 trott la, alongi dm (2000). the impact of shrimp pond effluent on water quality and phytoplankton biomass in a tropical mangrove estuary. mar. pollut. bull. 40:947-951. in ternationa l scholars journa ls african journal of environmental economics and management issn 2375-0707 vol. 2 (2), pp. 181-187, february, 2014. available online at www.internationalscholarsjournals.org © international scholars journals author(s) retain the copyright of this article. full length research paper a study of the degree of genetic variation among populations of cacao grown in nicaragua erielda corrales, regina lacayo and herman mariano department of environmental science, faculty of agriculture, bluefields indian and caribbean university, bluefields, nicaragua. accepted 05 january, 2014 the use of local germplasm of theobroma cacao l. as a basis for developing a breeding program is limited by the lack of information on genetic variability and relationships among populations. this study covered a sample of 70 cocoa trees in five geographical areas of nicaragua: el rama, nueva guinea, muelle de los bueyes, el castillo and los guatusos. the samples were molecularly analyzed using 10 microsatellite (ssr) dna. for the 10 locus was achieved amplification of 95 alleles. populations showed an average observed heterozygosity (ho) of 0.522, and nueva guinea was the population with the value of ho closest in value of expected heterozygosity (he). the latter obtained the lowest inbreeding rate (ƒ = 0.06). the value obtained for the average fixation index fst was 0.23, which allows you to catalog the cocoa plantations of southeastern of nicaragua with a moderate level of genetic diversity. the populations of muelle de los bueyes and el castillo presented the maximum value of genetic distance (0.1784). according to the principal coordinate analysis, the population distribution in a geometric plane can be grouped into two blocks. finally, the study phylogenetic populations of castillo and guatusos are more closely related to each other, than the rest of the population. keywords: theobroma cacao l., microsatellite markers, germplasm, consanguinity, heterocygosis introduction when the spanish conquistadors arrived in the new world, indigenous ancestors were using cacao as currency. the units of change were a hand, five seeds, quinque, fifteen seeds or tzontly forty cocoa beans (rocha, 1976, palma, 1975). since then, in mesoamerica, the cultivation of cocoa has a cultural and economic roots (henderson, 2007). cocoa, theobroma cacao (2n = 2x = 20) whose genome is 390 mega bases (mb) distributed in 10 chromosomes, is a neotropical species found in the mesoamerican region between 20 ° n and 20 º s, considered the area of domestication of cocoa (henderson, 2007). commercial cultivars of t. cocoa have a narrow genetic base (schnell, 2005). the *corresponding author email: erieldacorrales@gmail.com primary types of cocoa are forastero, trinitario (hybrid between forastero and criollo) and criollo, but motamayor (2008) proposes to classify the species into 10 clusters or groups: marañón, curaray, criollo, iquitos, nanay, contamana, amelonado, purus , nacional and guiana. de la cruz, (1995) presents divided theobroma into two sub-species: cocoa and sphaeorocarpum. beside, de la cruz (1995) suggests that the criollo and trinitario types should be considered as traditional crops and not like genetic groups. in addition, the amazon basin is the region that has greater cacao diversity (gentry, 1988). in nicaragua the cocoa plantations were developed hybrid genetic material derived from crosses between trinitario and forastero, and in addition endogenous criollo cocoa plantations, although it is unknown the status of biodiversity of the latter. the producers, through pedro et al. 181 social exchange of seeds, are responsible for the spread of cacao trees, which were not derived from clonal gardens or breeding programs. in nicaragua the annual production of cacao is 1,500 t -2.000 6.500 ha, with an approximate yield of 3.5 quintals mz-1 and priced at u$ 2-6 per kg (buchert, 2008). according to the international cocoa organization (2007) nicaragua is ranked 27 among cocoa-exporting countries and their production represents 0.026% of the global total. one of the main concerns of the world cocoa market is the ability of producing countries to supply the market continuously with fine cocoa quality, value added, as high oil content of cocoa, polyphenol groups (antioxidants) and terpenes (flavor and aroma) (othman, 2007; niemenak, 2006). in this regard it is important to understand the genetic diversity of cacao plantations in nicaragua due to its impact on production sustainability. therefore, the objective of this study was to establish the degree of genetic variation among populations of cacao grown in nicaragua and to determine the genetic diversity of cacao and extrapolate cocoa elite populations of the mesoamerican region. materials and methods plant material between february and june 2010 took place sampling plant material in nueva guinea, el rama, muelle de los bueyes, el castillo and los guatusos. from different trees, 70 samples were collected of immature leaves and not young. the tree selection was based on its productive potential and physical condition. the collection of each sample was accompanied with the raising of ecological agriculture tab of the plot where the tree stood. moreover, each tree was referenced satellite and labeling. each leaf was wrapped in paper towels and packed in a ziploc bag and preserved at -20 º c until processing. dna extraction prior to dna extraction leaf was rinsed several times with distilled water and drilled to obtain 200 mg leaf discs were placed in a 1.5 ml eppendorf tube which was immersed in liquid nitrogen and crushed using a mortar kontes. then we used a commercial medium for dna extraction, dneasy plant mini kit (qiagen). we proceeded with the protocol recommended by the commercial company with the variant that ap1 extraction solution was added 10 mg ml-1 of polyvinylpolypyrrolidone (sigma). the dna was quantified using biospectofotómetro (shimadzu uv-1200) and all dna samples were diluted to a concentration of about 5 ng ml-1 (saunders et al., 2004; zhang et al., 2006). microsatellite markers for molecular characterization was implemented 10 microsatellite (ssr) reported by saunders (2004) and considered the comments of zhang (2006). the name of microsatellite markers, the sequence of the primers, temperature, alignment and size are reported by saunders (2004). the pcr reaction was performed in a volume of 50 µl, containing 5 ng of genomic dna. all the pcr reactions contained: 1.0 u platinum taq dna polymerase (invitrogen), 0.2 mm dntps (invitrogen), 0.2µm of each primer (invitrogen), 1.5 mm mgcl 2, 1x buffer (20 mm tris-hcl, ph 8.0, 40 mm nacl, 2 mm sodium phosphate, 0.1 mm edta, 1 mm dtt, 50% glycerol). the conditions of the thermocycler (eppendorf) were: 4 min denaturation at 94°c, followed by 33 cycles of denaturation at 94 °c for 30 s, 1 min at a temperature of alignment of 46 °c or 51°c and 1 min extension at 72°c, with a final extension of 72°c for 7 min. electrophoresis amplified products were separated on a vertical electrophoresis apparatus (t-rex aluminum backed sequencer, model fb-seq-3545-fisher) in a denaturing gel (6 m urea) 6% polyacrylamide (fisher) running at 55w, 1700v by 2 or 3 h in 1x tbe buffer (qiagen) and detected by silver staining. the size of the amplified bands was determined with a commercial dna marker, 125bp dna ladder (invitrogen). statistical data processing the statistical program genetic analysis in excel v6.1 (genalex) (peakall, 2006) was used to determine the average number of alleles per locus, allele frequency, the percentage of polymorphism loci, the value of observed and expected heterozygosity, the pattern of alleles in the population, and the principal coordinates analysis (pca). the statistical program genetix 4.02 (belkhir, 2001) was implemented for statistical determination of nei genetic diversity and the calculation of the f-statistics (f-statistic of wright). the phylogenetic tree was constructed using phylogeny inference package (phylip v3.6) program and based on molecular data. other support programs used were arlequin v3.1 and convert (glaubitz 2004). results with the implementation of 10 microsatellite (ssr) was determined the variation at the level of allele. this was amplified 95 alleles with an average of 9.5 alleles per locus. in our study, y16988 locus has the highest earning 182 afr. j. environ. econ. manage. table 1. general statistics of the 10 microsatellites used in cocoa samples locus ssr † na †† alleles (bp) ‡ ho § he ¶ y16980 mtccir6 10 230, 235,240, 250, 275, 280, 285, 0.504 0.609 290, 295, 300 y16981 mtccir7 9 155, 160, 165, 170, 173, 175, 180, 0.684 0.653 185, 190 y16982 mtccir8 8 275, 280, 285,290, 295,300, 305, 0.611 0.507 310 y16985 mtccir11 11 210, 280, 285, 290, 295, 300, 303, 0.399 0.620 305, 310, 320, 470 y16988 mtccir15 15 220, 225, 230, 235, 240, 245, 250, 0.514 0.702 255, 260, 270, 275, 280, 290, 300, 310 y16991 mtccir18 9 305, 310, 315, 320, 325, 330, 340, 0.512 0.624 345, 350 y16991 mtccir22 7 270, 275, 280, 285, 290, 295, 300 0.395 0.419 y16998 mtccir26 7 280, 285, 290, 295, 300, 305, 310 0.492 0.498 aj271943 mtccir40 9250, 255, 260, 265, 270, 275, 280, 0.631 0.670 285, 290 aj271958 mtccir60 10 180, 185, 190, 195, 200, 205, 210, 0.476 0.670 215, 220, 225 total / average 95 0.522 0.597 † microsatellite representation; † † alleles number; ‡ base pare; § observed heterozygosity; ¶ expected heterozygosity. figure 1. silver staining 6% polyacrylamide gel of amplified molecular marker (mtccir18). mw: molecular weight of dna marker (invitrogen, 125 bp dna ladder). the numbers represent the samples of cacao analyzed a total of 15 alleles (table 1). this locus has a better chance of change in the frequency of any his alleles. the figure 1 shows the homozygous or heterozygous condition for a particular locus identified using molecular markers. viewing a single band determines the . homozygous condition; otherwise two bands mark the state of heterozygosity. an important parameter in genetic diversity of a population is the relationship between values for observed heterozygosity (ho) and expected pedro et al. 183 table 2. parameters of genetic diversity of the populations under study parameters genetic diversity population n¶ k¶¶ ho he ƒ§ hs † ht †† dm ‡ dst þ gst þþ el castillo 23 6.3 0.609 0.733 0.19240 los guatusos 10 4.3 0.548 0.619 0.16758 nueva guinea 11 4.3 0.555 0.562 0.06082 el rama 17 4.1 0.448 0.553 0.21885 muelle de los 9 3.6 0.450 0.520 0.19245 bueyes average 4.5 0.522 0.600 0.16642 0.5974 0.7781 0.2258 0.1807 0.2322 ¶ alleles number; ¶¶ average of alleles by locus; § coefficient of consanguinity; † genetic diversity inside of population; †† total genetic diversity ; ‡ absolute genetic differentiation; þ genetic diversity between populations ; þþ relative magnitude of gene differentiation among subgroups. table 3. estimation of fixation index (f-wright) þ for the 10 loci studied locus ssr fit † fst ‡ fis y16980 mtccir6 0.36338 0.23398 0.16892 y16981 mtccir7 0.39264 0.24157 0.19919 y16982 mtccir8 0.39278 0.23493 0.20633 y16985 mtccir11 0.35616 0.23794 0.15514 y16988 mtccir15 0.36169 0.24308 0.15671 y16991 mtccir18 0.35986 0.23041 0.16821 y16991 mtccir22 0.36392 0.22175 0.18268 y16998 mtccir26 0.37466 0.23081 0.18702 aj271943 mtccir40 0.38277 0.24788 0.17934 aj271958 mtccir60 0.37068 0.24939 0.16159 average 0.37234 0.23708 0.17770 þ calculated with a confidence interval 95% bootstraps based on 1000 replications per locus; † total fixation index; ‡ fixation index among populations; § fixation index within populations heterozygosity (he). heterozygosity is determined by the number of times (frequency) repeated the different alleles for a particular locus. table 1 show that in 8 of the 10 loci analyzed, the value of ho is less than the value recorded for he. the values for the fixation index also known as the coefficient of inbreeding (ƒ) is showed in table 2. this parameter determines the reduction of heterozygosity or outcrossing level. values can range from -1 to +1. the study did not yield any negative value for ƒ indicating that the populations under study there is no excess of heterozygosity. the distribution of variability within and between the populations studied is determined by the total genetic diversity, total heterozygosity (ht), heterozygosity for each population (hs) and genetic diversity among populations (dst). in this study the value of the ht is the result of the sum of (hs) and dst. the value reported for dst (0.1807, table 2) indicates that loci for the five populations studied has few heterozygotes and several types of homozygotes. the coefficient of genetic differentiation among populations (gst) is calculated by the relationship dst / ht, in the present study, the gst value of 0.2322 (table 2) and fst of 0.23708 (table 3), very close together, indicating that diversity among populations is supported by the presence of two alleles at a locus. the parameter that determines the absolute magnitude of genetic divergence (dm) expresses the variability between interpopulations with respect to the intrapopulations. this ratio is calculated by ndst / n-1, where n represents the number of populations. . 184 afr. j. environ. econ. manage. table 4. genetic distance (nei, 1972) among the five populations § under study south-eastern of nicaragua cagung ramb ca ( 23) 0.000 gu ( 10) 0.507 0.000 ng ( 11) 1.285 1.864 0.000 ra ( 17) 1.674 1.633 0.180 0.000 mb ( 9) 1.784 1.386 0.360 0.110 0.000 § el castillo, ca ; los guatusos, gu; nueva guinea, ng ;el rama, ra; muelle de los bueyes, mb figure 2. dimensional array of association (distance) between individuals from different populations (el castillo, ca; los guatusos, gu; nueva guinea, ng; el rama, ra; muelle de los bueyes, mb). the probability that two alleles of the same locus in an individual, are identical from the same offspring is denoted as the fixation index or coefficient of differentiation (f) and in the context of the present study, this index corresponds to the values f (table 3), where the subscripts representing the level of hierarchy, which are being compared. it is instructive to determine the proximity or the genetic distance between populations, to achieve this we determined the coefficient of genetic distance (table 4). this parameter allows compared pairs of populations of the five populations under study. the principal coordinates analysis (pca) can transform a number of variables correlated with a small number of uncorrelated variables, facilitating visual interpretation (graph) of the similarity or dissimilarity that . exists between individuals or populations. this relationship is embodied in a plane where the geometric distance between points reflects the genetic distance. the representation does not take into account the evolutionary processes, there is a phylogenetic tree and the relationship between two points is determined by calculating the frequency of alleles. in the figure 2 shows the distribution in a geometric plane of each sampled tree, represented by a point. if a pair of genes from different species or populations is developed in parallel and whether the degree of divergence between the two genes / populations implies that they have originated from the generation t, we can infer that these genes diverged from an ancestor common at time period t / 2. this reasoning allows us to construct the phylogenetic tree based on genetic pedro et al. 185 figure 3. dendrogram for the phylogenetic tree of the five geographical cacao populations included in this study. molecular phylogenetics tree is aimed at relationships for populations based on molecular data (allele and haplotype frequencies) distance. figure 3 shows the phylogenetic tree representing the relationships of five populations under study, based on the degree of similarity or number of shared characteristics. discussion the genetic variation between individuals or populations may manifest at different levels. the first level comprises a set of indicators that measures the change internally in the population (frequency of alleles, polymorphism, observed and expected heterozygosity, mean number of alleles per locus, effective number of alleles per locus, fixation index, etc. ) and the second level includes another set of indicators to measure the variation of a population relative to other populations (genetic distance, inbreeding coefficient, geometric correlation between genetic distance, cluster analysis, phylogeny, etc.). these indicators were identified in this study in brazil’s cacao plantation sereno (2006) used 11 microsatellite and report the amplification of 49 alleles . with an average of 4.45. a higher average (5.6) reported by zhang (2009) a study developed in the international collection of cocoa held in catie, botanical garden (costa rica). this study reports an average of 9.5 alleles per locus. value obtained due to the size of the area sampled. populations of trees sampled in this study are scattered and are not under the care of a germplasm collection. this study reported a deficiency of heterozygosity. it is very likely that the sampling would have developed among related trees (consanguinity). this means that a percentage of the sampled trees, have arisen from a facultative selfing or almost total, what makes the union of gametes not random. a second explanation could be the result of the wahlund effect, which occurs when the samples have different allele frequencies from two mixed populations. in relation to the divergence between ho and he values (table 2) for population el castillo and el rama, they are far apart, it is likely that one or more considerations for the hardy-weinberg (hw) are not being met (being diploid, sexually reproducing, not this cross generational, 186 afr. j. environ. econ. manage. gene with two alleles, the allele frequency is identical male and female gametes, random crossover, mutation and migration is ignored and, finally, that natural selection does not affect the alleles). the relationship between ho and he makes the link between alleles and genotypes frequency, also determines the proportion of genotypes in a population remain constant from generation to generation. obtain positive values for coefficient of consanguinity (ƒ) 0.06 to 0.21 denote different levels of heterozygote deficiency, probably due to the effect of consanguinity. this coefficient (ƒ) can also be considered as decreasing the proportion of heterozygosity at the crossing between related species. inbreeding tends to expose harmful and recessive alleles, a situation that may be affecting the productivity of cocoa farms in the study area. this phenomenon is referred as biparental inbreeding that occurs when genetic information of the progeny comes from two different parents but related to each other, this could be explain the level of abortions in cacao tree, inducing by incompatibility between gametes (hartl, 2007). the gst value 0.2322 indicates that most of the total variation is distributed among populations and the variation or diversity is not exclusive to any of the populations studied. beside a value of dm 0.225 suggest that variability present in the populations is supported by the diversity of the individuals in the population and not by the variations among populations. thus, fst is the probability that any particular locus in an inbred population have alleles identical by descent. the reported value for fst equal to 0.23 indicates that the populations studied have a moderate genetic diversity. fis index is a critical parameter in measuring genetic variation. this parameter has a minimum value of 0 (indicating absence of genetic divergence) and the maximum value of 1 (indicating fixation for alternate alleles in different subpopulations). also set heterozygosity deficiency in individuals within the population. based on data obtained from table 2 and 3, it shows that the cacao trees are showing an overlap of generations and fertilization preferably between related plants that grow close together and the place occupied by the mother plant. this situation reduces the genetic diversity of cacao plantations. however, the trend of loss of heterozygosity can be reversed by providing, in just a one generation the random crossing between no related trees. thus muelle de los bueyes (mb) and el castillo (ca) are the populations with the highest distance value 0.1784, being reported as the most diverse populations analyzed. conversely, the closest are the rama (ra) and muelle de los bueyes with a distance value 0.110, providing a lower limit differentiation. this value determines the proportion of the genetic elements (alleles, genes, gametes, genotypes) that share the two populations compared. a value equal to zero indicates that population are absolutely identical. regarding to the pca analysis, the points that cross from one quadrant to another indicate genetic similarity between individuals (figure 1). also seen in certain quadrants as there are points that fit perfectly one on another as if they were a single point. observe how population tend fall into two main sections. one block represented by the populations of los guatusos and el castillo, and a second block consisting of el rama, muelle de los bueyes and nueva guinea. within this second group, the population of el rama, has a heterogeneous profile of individuals closely linked to populations of muelle de los bueyes and nueva guinea. the phylogenetic tree permit grouped populations in relation who submit the smallest genetic distance. each branch represents the most recent common ancestor. in our study, less connected populations or "neighbors" from the point of view common ancestor belong to los guatusos and el rama. conclusion in conclusions, the present study generated information on the genetic diversity of cacao grown in the five villages in nicaragua and is able to generate information regarding the degree of relatedness between populations, genetic distance between populations, establish the level of genetic diversity and heterozygosity. based on determined parameters we can conclude that the genetic diversity of cacao in the study area is moderate. all this information would provide the baseline for establishing a breeding and conservation program of local biodiversity of 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research paper valuing environmental impacts of coastal development projects: a choice experiment application in spain david hoyos 1 *, pere riera 2 , javier fernández-macho 3 , carmen gallastegui 4 and dolores garcia 5 1 department of applied economics iii (econometrics and statistics), university of the basque country, e48015 bilbao, spain. 2 institute of environmental science and technology, autonomous university of barcelona, campus uab, e08193 bellaterra, spain. 3 department of applied economics iii (econometrics and statistics), institute for public economics, university of the basque country e48015 bilbao, spain. 4 department of foundations of economic analysis i, institute for public economics, university of the basque country, e48015 bilbao, spain. 5 departament d'economia aplicada, universitat de les illes balears, e-07122 palma de mallorca, spain. accepted 22 july, 2013 this paper presents the results of an empirical application aimed at estimating the economic value of the potential environmental impacts to mount jaizkibel (spain) resulting from the construction of a new seaport over its hillside. a choice experiment technique is applied for an ex-ante natural resource damage assessment in monetary terms. the results revealed that, depending on the extent of the environmental damage, the social welfare loss would be between 172 and 535 million euros per annum. key words: choice modelling, environmental valuation, social welfare, coastal management. introduction sea coast is an appreciated natural resource for human beings because of the ecological, cultural, social and economic values it bears. human settlements have historically established near the coast. with just 4% of earth’s total land area, coastal areas and small islands house more than one-third of the world’s population (barbier et al., 2008). this is also the case of spain. with a coastline 8,000 km long (4,000 km of cliffs, 2,000 km of beaches, 1,000 km of low coast, and around 600 km of artificial areas), it is estimated that nearly half of its population live in its coastal zones. human pressure over the iberian coast has increased over the last decades. in the basque country, a spanish region in the north of the iberian peninsula, land artificialisation has grown 14% between 1987 and 2000, and the surface occupied by seaport areas has grown 72% for the same period, from *corresponding author. e-mail: david.hoyos@ehu.es. nearly 366 ha in 1987 to 629 ha in 2000 (ose, 2007). developmental monetary benefits are often raised as a justification for diverse coast artificialisation projects, but they are rarely confronted with the environmental benefits that its conservation may entail. the absence of a monetary expression for the goods and services provided by coastal natural ecosystems often implies that they are implicitly equalled to zero. scarcity of quantitative information for policy decision making has often been a concern of coastal managers (christie and white, 1997; chua, 1993). economic valuation aims at providing estimates of willingness-to-pay (wtp) of citizens to achieve/avoid certain environmental quality changes. different economic valuation techniques have appeared to estimate in monetary terms the value of non-market goods. existing approaches are broadly grouped into revealed preferences methods (like hedonic pricing and travel cost) or stated preferences methods (like contingent valuation and choice experiments). stated hoyos et al. 064 preference methods have received growing attention mainly due to their flexibility and ability to measure not just use values (as revealed preference methods) but non-use values of natural resources as well (mitchell and carson, 1989). the main difference between the contingent valuation method and the choice experiment (ce) methodology is that while in the former individuals face the valuation of one good with varying prices, in the latter individuals face the valuation of a bunch of goods (or one good with multiple attributes) and different prices. the underlying idea of ces is that if human-induced changes in the state of an ecosystem can be coherently represented by a group of attributes, people’s choices provide substantial information over their preferences regarding alternative states of the environment (hoyos, 2010). this paper examines the use of a ce methodology to assess the economic value of potential environmental impacts that could be associated with the construction of a new seaport over the hillside of mount jaizkibel (spain). jaizkibel is a protected natural resort because of its landscape and geological interest as well as its fauna, flora, and seabed. the values obtained can be employed in an ex-ante assessment of the environmental costs associated with coastal development projects useful for decision making. case study pasaia, a city located on the spanish cantabrian coast, near the border with france, has had maritime and commercial activities in its natural port since the 12th century. even though up to the 19th century it was mainly dedicated to ship building and fishing, its main activity during the 20th century has been the traffic of materials from heavy industry. in recent years, the port authority of pasaia has promoted a project to develop a new seaport outside the bay, in front of mount jaizkibel. defenders of this project claim that it will be very profitable to the economic activity of the region while opponents argue that the environmental loss associated with the project advice against its construction. figure 1 shows the current seaport (a) and three projected seaports (seaport projects 1, 2 and 3), with different capacity and affections to jaizkibel natural site. mount jaizkibel is a 2,434 ha natural site located at 1° 50’ west longitude and 43° 22’ north latitude. it belongs to the european natura 2000 network because it is considered a site of community importance for the atlantic biogeographical region, thus protected under european environmental legislation (habitat directive 92/43/eec). the landscape of this area is especially interesting because the mountain goes along the coast with abrupt falls in the western part, forming cliffs up to 240 m high. the cliffs are considered of geological interest due to the layout of sandy stratum. they host the armeria euskadiensis, an endemic plant of the basque coast catalogued as an endangered species. in the eastern part, the terrain is not so abrupt and there are small beaches and precipices formed by the curse of streams ending in the cantabrian sea. in these areas, one can find some interesting species of flora such as tropical ferns (woodwardia radicans and trichomanes speciosum), very rare in the rest of europe. certain spaces maintain the original tree cover, oak grove of quercus robur and quercus pyrenaica. the rest of jaizkibel conforms a non-wooded forest area with some brushes and some pastures associated to local baserri (autochthonous farms). some colonies of lesser black-backed gull and yellowlegged gull (larus fuscus and larus cachinnans) nest in jaizkibel’s cliffs. other interesting birds, such as the european storm-petrel (hydrobates pelagicus), green cormorant (phalacrocorax aristotelis) and peregrine falcon (falco peregrinus) can be found in this natural area. over the mainland there are numerous species of amphibious, reptiles and mammals such as palmite newt (triturus helveticus), midwife toad (alytes obstetricans), dark green snake (coluber viridiflavus) and greater horseshue bat (rhinolophus ferrumequinun). in its seabed, it harbours different types of molluscs, sea urchins and crustaceans. jaizkibel’s seabed also harbours various types of seaweed: green, red and brown. furthermore, jaizkibel has one of the most important lands of red seaweed of the basque coast. in short, jaizkibel’s most outstanding environmental attributes are: landscape, autochthonous fauna and flora, seabed life, and environmental services such as sweet water, clean air and maintaining of current stream, swell and sediment transportation regime. the construction of a new seaport would involve a number of different stressors that could damage natural site’s landscape values, habitats and species. the identification of potential damages was based on published reports, public institutions’ and ngos’ reports and assessments made at the site. according to these information sources, anticipated environmental impacts related to the construction and operation of the seaport would include: direct loss of habitat, disturbance to sensitive habitats and species of avifauna, air pollution, increased human access to wildlife, risk of fire and other disturbance to sensitive habitats and species. detailed information on the environmental values and potential damages to jaizkibel may be found in pozueta (2004). survey design a valuation survey was conducted in the basque country in order to determine the value of the potential environmental impacts to jaizkibel area. the questionnaire 065 afr. j. environ. econ. manage. figure 1. three scenarios for the future seaport of pasaia. started by describing the jaizkibel natural site. next, certain changes in the quality of mount jaizkibel’s main attributes were described. it was stated that if the site was not to be protected in the future, it could be affected by human activities. the market institution was detailed next, where compulsory monetary contributions from the basque residents would contribute to the conservation of the site. the trade-offs between payments and degree of preservation of the different attributes were presented in choice sets of two alternatives and an opt-out situation, as will be detailed shortly. the final part of the questionnaire was devoted to some debriefing and sociodemographic questions. the selection of attributes and levels is an important aspect in ce given that respondents are to make choices characterized by those attributes and levels (hensher, 2007). previous investigation on environmental characteristics of jaizkibel natural site, experts’ advice and focus groups facilitated the definition of environmental attributes and levels of provision. furthermore, a pilot survey using open-ended contingent valuation questions helped in identifying the appropriate levels of the payment attribute. at the beginning, six non-monetary attributes were identified: landscape, flora, avifauna, seabed, groundwater and air quality. however, the last two attributes (groundwater and air quality) were dropped mainly because of their relative little importance as suggested by experts and focus groups. table 1 reflects the attributes and levels considered in this study. they were, (1) landscape, measured by the percentage surface from which today’s landscape could be seen in the future; (2) flora, measured by the future level of protection of today’s population of a. euskadiensis endemism; (3) avifauna, measured by the future level of protection of today’s population of lesser and peregrine falcons; (4) seabed, measured by the future level of protection of today’s extension of red algae; and (5) annual contribution in euros, varying from 5 to 100 €. respondents’ understanding of the valuation exercise is a critical aspect of any stated preference survey. accordingly, the graphic and verbal description of the future environmental changes for the non-monetary attributes was tested in detail in focus groups. landscape changes seemed to be better understood showing pictures with a different degree of visual affection, as shown in figure 2. the importance of flora, fauna and seabed attributes seemed to be better captured by its most prominent species, the a. euskadiensis, the lesser table 1. attributes and levels considered. attribute level landscape (%) 40* 60 80 100 flora (%) 50* 70 85 10 fauna (%) 25* 50 75 100 seabed (%) 50* 70 85 100 annual payment 0 €* 5 € 10 € 15 € 20 € 30 € 50 € 100 € *business-as-usual level. figure 2. example of choice set with different protection alternatives used in the valuation exercise. and peregrine falcon, and the red algae respectively. these attributes’ graphical representation corresponded with the actual location of these species’ populations according to the experts’ advice. when the percentages of protection of these attributes were inferior to 100%, some actual location of its most prominent species’ populations were deleted accordingly (figure 2). none of the levels of protection were set to zero in order to avoid plausibility problems related to the survival of different species. combining all these attributes and levels, near two thousand different combinations are obtained (4 4 x7 1 ). a main effects fractional factorial design with second order interactions was used to reduce the number of alternatives to 96 pairs of protection alternatives (louviere et al., 2000). further, the alternatives were grouped in 24 blocks of four choice sets containing two alternative protection programmes plus the business-asusual (bau) option. the burden of the choice task was checked in the focus groups. as a result, the final version of the questionnaire had four choice sets, each formed by the bau option plus two protection alternative programs (programs a and b) as shown in figure 2. the proposed payment vehicle was an annual contribution to a foundation exclusively dedicated to protecting jaizkibel natural site that all basque citizens would have to make. the questionnaire was administered through in-person computer-aided individual home interviews. respondents could read the questions in the computer’s screen and listen to a recorded voice, with three different languages available: basque, spanish and french. the relevant population considered was the population from the hoyos et al. 066 067 afr. j. environ. econ. manage. basque country, accounting for 2.5 million people being at least 18 years old. a pilot survey was conducted in october 2006, while the final survey was undertaken between november and december, 2006. a stratified random sample of 600 individuals was selected from the relevant population. the strata used included age, gender and size of the town of residence, following official statistical information from the basque statistics institute (eustat). in each location, the questionnaires were distributed using random survey routes. methodology ce belongs to the family of conjoint analysis methods, defined by green and srinivasan (1990) as “any decompositional method that estimates the structure of a consumer’s preferences given his or her overall evaluations of a set of alternatives that are pre-specified in terms of levels of different attributes.” choice experiments technique is based on lancaster’s characteristics theory of value and random utility theory (hanley et al., 1998). following random utility theory, consumers pursue the maximisation of utility in decision-making processes. thus, the utility an individual i obtains from alternative j (uij) can be formalised as; uij  vij  ij , where vij is the part of utility that is observable (and thus affected by the attributes of this option), and εij is the non-observable part or random component. as a consequence, individual i will choose alternative j instead of k if her utility increases, this is, if: uij > uik for k≠j however, given the existence of a random component, the choices can be written in probability terms. the probability that individual i chooses alternative j instead of k from a finite set of alternatives c, would be: pij  probvij  ij  vik  ik;k c. the stochastic component of utility is usually assumed to be independent and identically distributed (iid) and gumbel distributed (mcfadden, 1974). thus, the conditional logit model can be written as: pij  evij m k 1 e vik , where ω is a scale parameter, which is inversely proportional to the error term’s standard deviation and it is generally assumed to be one so that the variance of the error term is constant. the equation aforestated can be estimated by means of a multinomial logit (mnl) regression. the mnl model relies on the assumption that choices are consistent with the independence of irrelevant alternatives (iia). this axiom states that the ratio of the probabilities of choosing one alternative over another is not affected by the presence or absence of other alternatives in the same choice set (louviere et al., 2000). in case of violation of iia, the parameters estimation would be biased. the iia property is usually checked using the test proposed by hausman and mcfadden (1984). the structure of the mnl model depends on the form adopted by the indirect utility function. to estimate the main effects, an additive indirect utility function of the following form may be used: vij   0  1atrib1   2 atrib2   3 atrib3  ...  natribn where β0 is the constant term and β1 … βn are the coefficients of environmental attributes. the constant term, β0 (that can be interpreted as a vector of alternative specific constants, one for each alternative considered in the choice set) reflects the influence on choice of non-observed attributes relative to specific alternatives. alternative specific parameters, however, may be dropped in dealing with non-labelled experiments (hensher et al., 2005). individual marginal wtp estimates represent the average maximum amount of money a person is willing to give in exchange for an additional unit of the environmental good, that is they represent estimations, ceteris paribus, of the value of a marginal change in a given attribute. in order to estimate the wtp, the interaction between multiple attributes, if relevant, is to be taken into account as well as the influence of the alternative specific constant. welfare estimates for mnl models may be obtained from cs  1 ln e vi 0 ln e vi1  , where cs represents the compensating surplus, α is the marginal utility of income, and vi0 and vi1 are the indirect utility functions of alternative i in the status quo (0) and in the change considered (1). in our case, the previous expression can be rewritten as: cs  1  landscape   avifauna  seabed  flora  cos t and simplifying the aforestated equation, the marginal value of a change in one attribute with respect to another is measured through the ratio of both coefficients. therefore, the wtp for each of the environmental attributes is obtained by dividing the coefficient of each attribute by the cost attribute coefficient: wtp   attribute  cos t the cost parameter is interpreted as the marginal utility of income. results and discussion a fixed parameter logit model specification was estimated using limdep econometric software (greene, 2007). the results are shown in table 2. all the coefficients of the environmental attributes have the expected signs (positive, meaning that conservation is more highly valued than loss) and are significant at 1% level. the negative coefficient of the price attribute is also expected, indicating that the probability of accepting an annual hoyos et al. 068 table 2. fixed parameter logit model estimation. covariate (attribute) coefficient t-statistic landscape 0.02028 7,38 flora 0.01272 3,79 avifauna 0.00998 4,90 seabed 0.00925 3,90 cost -0.01462 -7,17 log-likelihood -590.4531 log-likelihood at 0 -627.1635 observations 687 contribution for protecting mount jaizkibel’s attributes decreases as the price increases. no relevant second order interactions were found. regarding the iia property (hausman and mcfadden, 1984), it was tested whether the full mode, estimated with all three alternative choices, was equivalent to a restricted model where one of the alternatives was eliminated. in every case, the null hypothesis that iia holds for this data set cannot be rejected, as shown in table 3. table 4 shows point estimates and 95% confidence intervals of the marginal wtp estimates for the four attributes. the positive signs of the marginal wtp estimates for the environmental attributes indicate that, everything else being equal, respondents would be better off on average with an increase in the level of those attribute. the individual wtp for a 1% improvement of jaizkibel’s landscape is estimated at 1.39 euros (2006) per person and year. similarly, the wtp for a 1% improvement in the quality of the flora, avifauna and seabed is estimated at 0.87, 0.68 and 0.63 euros per person and year respectively. three damage scenarios to the environmental attributes of mount jaizkibel can be approximated based on the expected impacts associated with the seaport projects presented in figure 1. the scenarios are based on the report by pozueta (2004) and experts’ opinions. they took into account the current geographical location of the a. euskadiensis, the lesser black-backed gulls and peregrine falcons, and the red algae. experts’ advice was followed in order to determine the specific impact of each harbour project on the population of these species. figure 3 summarises the main impacts of each project to the identified environmental attributes. this figure shows, for example, that the largest harbour project (seaport 1) would imply that 40% of current landscape, 50% of current flora, 25% of current fauna and 50% of current seabed would remain preserved in the future. annual welfare loss due to the environmental degradation provoked in the construction of each future seaport was calculated using the compensating surplus equation for a linear additive utility function explained before. table 5 shows the individual wtp estimates for table 3. iia/iid test statistics for the mnl model. alternative dropped χ2 df probability business-as-usual 6.462 5 0.264 alternative 1 0.926 5 0.968 alternative 2 6.560 5 0.255 table 4. marginal wtp for protecting mount jaizkibel’s environmental attributes, in euros 2006 per person and year. attribute marginal wtp 95% confidence interval landscape 1.39 (0.98,1.86) flora 0.87 (0.41,1.31) avifauna 0.68 (0.41,0.95) seabed 0.63 (0.33,0.96) 95% confidence intervals were calculated using the krinsky-robb procedure (krinsky and robb, 1986). each scenario. the wtp corresponds to the mean amount of money, in 2006 values, that one individual would be willing to pay at most to avoid an environmental damage as described for each scenario. thus, on average an individual would be willing to pay annually an average of 209 euros to avoid an environmental damage as described in the seaport 1 degradation scenario, 134 euros for the seaport 2 degradation scenario and 67 euros for the seaport 3 degradation scenario. finally, the annual welfare loss associated with the degradation scenarios described above is calculated by multiplying the mean wtp by the relevant population (2.5 million residents), as shown in table 6. the annual welfare loss of the deterioration of the environmental quality of jaizkibel associated to the harbour development may be estimated between 172 and 536 million euros, depending on the project to be undertaken. in the seaport 1 scenario, annual welfare loss is estimated at 535 million euros (213 million for landscape, 110 for flora, 130 for avifauna and 81 for seabed). in the seaport 2 scenario, annual welfare loss is estimated at 344 million euros (142 million for landscape, 66 for flora, 87 for avifauna and 49 for seabed). and, in the seaport 3 scenario, annual welfare loss is estimated at 172 million euros (71 million for landscape, 33 for flora, 43 for avifauna and 24 for seabed). in sum, this empirical application has attempted to show how economic analysis can be used in coastal management in order to assess ex-ante the desirability of a development project according to its environmental effects. the ex ante assessment of potential environmental impacts faces two significant shortcomings: absence of market prices for environmental damages and reliance on hypothetical behaviour that can only be 069 afr. j. environ. econ. manage. figure 3. mount jaizkibel estimated scenarios according to the impacts of three future seaport projects of pasaia. table 5. compensating surplus for different degradation scenarios, in euros 2006 per person per year. scenario level of damage individual wtp landscape (%) flora (%) avifauna (%) seabed (%) seaport 1 60 50 75 50 208.74 (126.26-296.87) seaport 2 40 30 50 30 134.17 (81.71-190.34) seaport 3 20 15 25 15 67.09 (40.86-95.17) table 6. annual welfare loss, in millions of euros 2006. wtp landscape flora avifauna seabed aggregate seaport 1 212.89 110.60 130.76 81.16 535.52 (150.85-287.07) (52.57168.30) (78.32-183.22) (42.18-123.01) (323.93-761.61) seaport 2 141.93 66.36 87.17 48.76 344.22 (100.57-191.38) (31.54-100.98) (52.21-122.15) (25.31-73.81) (209.63-488.32) seaport 3 70.96 33.18 43.59 24.38 172.11 (50.28-95.69) (15.77-50.49) (26.11-61.07) (12.65-36.90) (104.82-244.16) captured by sp methods. the use of ce methodology in this context is thus justified by two reasons: first, as a sp non-market valuation technique, it allows to estimate hypothetical environmental quality changes; and secondly, it is able to separately estimate the preference of individuals for different environmental attributes and marginal values. the flexibility of this methodology allows assessing a wide variety of potential damages to a diverse set of environmental attributes. some applications of ces have been reported for the economic valuation of coastal and marine resources (johnston et al., 2002; lew and larson, 2005; rein, 1999; samonte-tan et al., 2007), although, to our knowledge, the use of ce in this context is non existent. hoyos et al. 070 table 7. contingent valuation studies of rural landscape changes, with wtp expressed in euros 2006 per person and year. study landscape change population individual wtp santos (1998) conserving the pennine dales (esa, england) landscape’s attributes visitors 78,84 96,17 willis and garrod (1991) conserving the yorkshire dales (uk) today’s landscape visitors 59,89 89,43 santos (1997) conserving today’s agricultural landscapes in the peneda-geres (np, portugal) visitors 64,83 75,72 santos (2007) multiple study average 42,40 64,56 santos (2007) meta-analytical model predictions based on similar studies visitors 48,16 97,96 source: santos (2007). the wtp results seem to be in line with those from similar studies. table 7 contains a summary of the mean estimates of different studies and the results from a metamodel built upon contingent valuation studies of environmentally sensitive areas by santos (2007). in the reported studies, the wtp ranges from 42 to 98 € per visitor and year. these estimates are slightly higher than the wtp for protecting the mount jaizkibel today’s landscape (between 27.80 and 83.40 € per person and year depending on the percentage degradation considered). this difference may be explained, among other things, because the population surveyed in these studies were visitors (normally stating higher wtp than non-visitors) while in jaizkibel the general population was surveyed. conclusions coastal managers and policy-makers often need to evaluate policies affecting the welfare of the population. if relevant environmental costs are not incorporated in coastal developmental project assessments, welfare measures will be probably biased. ce methodology is a valuation method that can be used to value impacts related to coastal development projects. this paper has used this methodology to perform an economic assessment of potential non-market environmental damages to jaizkibel natural site (spain) associated to the construction of a new seaport in pasaia. the valuation exercise was based on a questionnaire survey administered in the basque country (spain and france) to a representative sample of the population. on average a basque citizen would be willing to pay annually 1.39 euros for avoiding 1% deterioration of mount jaizkibel today’s landscape; 0.87 euros for avoiding 1% deterioration of today’s flora; 0.68 euros for avoiding 1% deterioration of today’s avifauna; and 0.63 euros for avoiding 1% deterioration of today’s seabed. according to this estimates, the economic value of the future environmental damage provoked by a new seaport in pasaia was estimated between 172 and 535 million euros per annum. this value depends on the future environmental damage that the construction of a new seaport may cause. in case of constructing seaport 1 (figure 1), the environmental damage was estimated in 535 million euros per annum. in case of constructing seaport 2, the environmental damage was estimated in 344 million euros per annum. and last, if seaport 3 was constructed, the environmental damage was estimated in 172 million euros per annum. acknowledgements the authors acknowledge the financial support from the department of environment of the basque government and ihobe, s.a., from the department of education of the basque 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procurement and disposal of public assets authority, uganda. *corresponding author. e-mail: bbasheka@yahoo.co.uk. accepted 12 june, 2013 traditionally, the success of projects is measured on time, cost and quality parameters; although, most construction projects in uganda have not performed well on each of these parameters. in this paper, we identify important indicators that are useful for measuring contractors’ performance in uganda’s context. the paper develops a simple performance measurement framework for measuring performance of contractors. it also identifies a set of challenges faced by contractors in uganda that need the attention of policy makers and those in managerial positions. the findings are original and add to the stock of existing knowledge in understanding the unique context of the construction industry in developing countries. key words: performance management, construction projects, customer satisfaction. introduction there is probably no sector that has significant impliand dynamics of most construction projects create cations on the daily lives of human creatures than the difficulties for even the best project managers (nguyen et construction industry. it is universally accepted that for al., 2004). this complexity extends to even attempting example, the wells and bore holes where human beings measuring the sector‟s performance. in uganda, con get water as a source of life, the buildings where we live struction firms pay direct taxes to local and central and work, the roads and bridges we drive on, the utility government through the normal taxable incomes and distribution systems we use, the railways, airports, ferries mandatory taxes before participating in public procure and harbours we travel and trade from, dams and power ment as provided by the county‟s procurement legal lines that give us electricity, are all products of this vital regimes. in an indirect way, these firms still pay taxes industry. the construction industry accounts for a through the materials they purchase for construction significant portion of the world‟s gross domestic product. works in various government projects. in the developing world, the construction sector provides construction project development involves numerous a substantial source of employment to the majority of parties, various processes, phases and stages of work poor citizens of those countries. in this connection, the and a great deal of inputs from both the public and sector offers a sound basis for revenue collections that private sectors with the major aim of bringing the project enable governments collect direct and indirect taxes to to a successful conclusion (takim and akintoye, 2002). provide public services. the level of success in carrying out construction projects in developing countries, the biggest customer of the depends on the quality of management, financial, tech private construction industry is the government (okpala nical and organizational performance of the respective and aniekwu, 1988). the intrinsic complexity, uncertainty parties. this needs taking into account the associated risk table 1. showing construction real gdp growth rates, 2003/04 to 2007/08. fy 2003/04 2004/05 2005/06 2006/07 2007/08 % contribution 10.0 14.9 23.2 14.3 6.0 source: uganda background to the budget 2008/09. management, business environment, economic and political stability. the finished product in any industry requires satisfying a certain standard to provide customer satisfaction and value for money (vfm). in the construction industry, achieving quality of the finished product is no less than in any other industry (chan and tam, 2000). a construction project is acknowledged as successful when it is completed on time, within budget, and in accordance with specifications and in accordance to stakeholder‟s satisfaction (takim and akintoye, 2002). in the same argument, teo and ofori (1999) inform us that the main rationale and impetus for the development and implementation of procurement arrangements for construction projects is to increase the likelihood of the participants in the construction process to satisfy the client's objectives. however, as recently observed by eshassi et al. (2009) the business environment for the construction sector continues to change rapidly. in such circumstances the changes from the environment affect the way contractor‟s performance is measured. in south africa for example, hanson et al. (2003) informs us of several factors including conflict, poor workmanship, and incompetence of contractors identified as dissatisfaction factors negatively affecting project performance). relatedly, a study by mbachu and nkando (2007) in south africa established that quality and attitude to service were some of the factors that affected delivery of projects. such contextual analysis enables us have unique examples for understanding the measurement challenges for contractor performance. in uganda, the liberalization of the economy since the 1990s promoted development in all sectors. our interest in this paper, however, is directed to the building and construction sectors. in line with the requirements of the development partners, the government of uganda reformed its road sub-sector in an effort to accelerate its economic growth. in the past 10 years, a lot of emphasis was placed on the development and maintenance of the national road network. the government‟s commitment in this effort was manifested by increased funding to the sub sector to a tune of ushs 1.1 trillion budgeted for the fy 2008/2009. this sector is estimated to have grown by an average of 5.7% per annum for the last 10 years with benefits to the entire economy. the country‟s economy has more than doubled; estimated to have had an average growth of about 6.0% per annum. the country‟s gdp series which estimate the real size of the economy (measured at factor cost) indicates an 8.9% p.a estimate during fy2007/08 compared to a 7.4% in fy2006/07. the contribution of the construction industry to the real gdp growth is shown in table 1. in line with the subject of procurement, rwelamila et al. (1999) informs us that most african construction practitioners adopt procurement approaches, which do not consider local factors, leading to inconsistent and unpredictable outcomes. he suggests that the poor construction performance in most african countries emanates from lack of adequate consideration for cultural issues of project management parties (rwelamila et al., 1999). uganda has not had a known construction policy for several years. consequently, for a long time, the private sector represented by an association of contrac-tors [the uganda national association of building and civil engineering contractors (unabcec)] has been pressurizing government to put in place such a policy to spell out the required standards and processes for an effective construction industry. in return, the government has now accepted such pressures and a policy now approved by cabinet awaits parliamentary approval. with the policy in place standards to bring value for money in construction services has received significant attention. contractors will be expected to follow prescribed procedures as well as their services to the required standards and quality; failure of which would attract sanctions. purpose of the study in the last few years, multiple works about supply chain performance management have appeared in the specialized literature, although this discipline is relatively recent (saiz et al., 2007). since the late 1980s, performance management in government has received increasing interest fostered by the „re-inventing government‟ movement (osborne and gaebler, 1992). performance measurement has been viewed as critical for realizing the short and long terms goals of an organization. its results can be used by decision makers to improve programme performance. increasing the efficiency of public services has been promoted by new public management theorists. due to this new approach to running government business, cutting through red tape, minimizing public waste and value for money have been important drivers for the introduction of performance measurement in the public sector as suggested to us by greiling, (2006). while studies have been done to measure the performance of the entire public sector machinery, limited scholarly studies have been done to the study of contractor basheka and tumutegyereize 106 107 afr. j. environ. econ. manage. performance and an understanding of the challenges that contractors themselves encounter in delivering their crucial services. in this study, we sought to undertake such a study as a way of exploring the measurement indicators for the performance of contractors in uganda‟s context. secondly, our study was driven by the desire to identify the industry-specific challenges that affect contractors and presumably limit them from offering quality services. in this regard, our study aimed at providing answers to two important questions: namely (1) what critical performance measurement variables should be considered for assessing contractors‟ performance in uganda? and; (2) what major challenges are faced by contractors in uganda? by answering such questions, a ground work for subsequent empirical studies on this sector would be provided to the academic community but also lessons of application to the practicing managers will be discerned. literature neely (2005) tells us that performance measurement is the process of quantifying the efficiency and effectiveness of actions. for a performance measurement system to be regarded as a useful management process, it should act as a mechanism that enables assessment to be made, provides useful information and detects problems, allowing judgment against certain predetermined criteria to be performed. more importantly, the system should be reviewed and updated as an ongoing process (ong and the, 2008). with the increased interest in performance measurement, a systematic shift of emphasis from financial performance measures to non-financial measures of performance has emerged quite significantly. traditional accounting and financially-oriented performance measurement systems are no longer adequate to evaluate the firm‟s performance. traditionally performance measurement involved management accountants through the use of budgetary control and the development of purely financial indicators such as return on investment (chenhall, 1997). as busi and bititci, (2006) ably observe performance measurement has developed into a relatively broad body of literature to cover both financial and nonfinancial measures but the areas of under-development still exist. measuring performance of government should draw a considerable amount of attention from professional associations, scholars and practitioners as suggested to us by holzer and kloby, (2005). for construction projects, there have been different measurement indicators. the generally perceived factors that influence quality performance can be grouped under the headings of client, project, project environment, project team leaders, project procedures and project management procedures (chan and tam, 2000). research has documented that sophisticated and specialized clients having a better chance of success are critical variables. the nature of the client (whether from the public or private sector), the clarity of the project mission, their competency in terms of ability to brief, make decisions, and define roles, have been found to significantly contribute to the quality of a project (naoum,1991). according to walker (1994), project scope, nature of the project and complexity of the project(the project characteristics)also have an influence on the performance of projects; in addition to the environment in which a project operates. unlike in uganda, other developing countries have witnessed a number of studies that have examined the factors affecting the performance of projects. for example, farid and el-sayegh (2006), gives us interesting findings on the significant factors causing delays in the united arab emirate (uae) construction industry. the study reports shortage of skills of manpower, poor supervision and poor site management, unsuitable leadership, shortage and breakdown of equipment as some of the major causes of delays in construction projects. in a recent study of the factors affecting the performance of construction projects in the gaza strip, enshassi et al. (2009), reports to us a large number of related performance factors such as time, cost, quality, client satisfaction, client changes, business performance, health and safety, productivity and innovation, and environmental characteristics, among others. in a study of the thai highway contractors, prasertrungruang and handikusumo (2007) observed that the construction business is a sector that relies primarily on high utilization of machinery. further, day and benjamin, 1991, contend that equipment has long been considered as one of the key factors for improving contractors‟ capability in performing their work efficiently and effectively. however, contractors usually face difficulties in getting all the equipments they need, especially capital investments, in the acquisition phase, due to financial constraints. it is estimated that the procurement of equipment constitutes up to 36% of the total construction project cost (yeo and ning, 2006). as the project progresses to the implementation phase, the problems of contractors also change. one of the major problems faced during this phase is the high breakdown rates of the equipment and accidents from unskilled operator abuse as well as poor training on equipment use (edwards and nicholas, 2002; gann and senkar, 1998). other problems in the subsequent phases relate to maintenance and determining the economic life of the equipments before their disposal. while these factors may be regarded in the context of a particular study, they can be applicable in other contexts. naoum, (1991) believes that the changes in the environment can create uncertainty not only regarding prices but also in terms of investment in the work of the organization, which will affect the demand for the building. in this same debate, the procedures adapted during the construction process, like the form and method of tendering, are key variables for quality performance basheka and tumutegyereize 108 (serpell and alarcon, 1998). together with a project team, a group of construction professionals and personnel from one or more organizations can combine to fulfil the necessary design, detailing and construction functions comprising the construction project that is committed to their professional work ethics and construction projects and can achieve excellent performance. beale and freeman (1991) believe that the performance of the project team on construction projects will, to a great extent, depend on the skills and experience of several key project leaders. methodology the methodology adopted in the study was two-fold. firstly, there was administration of a self administered questionnaire to a group of construction professionals. these professionals included engineers who prepare solicitation documents (sds) for construction works, supervise works and certify completion of works and the rest of these engineers were managers and policy makers under the central and local government levels but coordinated by the uganda national roads authority. in this category, 133 respondents out of the expected 167 randomly selected respondents returned the usable survey questionnaire suggesting a response rate of 76.9%. the returned questionnaires were checked for completeness before quantitative data was entered into the spss package, cleaned and then subjected to preliminary analysis partially check for outlier variables. the study tested for the reliability of the data using cronbach alpha coefficient which returned a value of 0.85. we used exploratory factor analysis to determine content and construct validity. secondly, we conducted in-depth interviews with the representatives of the uganda national association of building and civil engineering contractors (unabcec), as well as ministry of works and transport officials, to get their own view of the performance of the construction sector in uganda. in this way, we benefited from methodological triangulation and validation of results which had been obtained from the first categories upon whom the questionnaire was administered. the first set of results for this study was generated from 133 respondents. in terms of gender, 103 (77.4%) were male respondents compared to only 30 (22.6%) who were female respondents. this information reflects the long perceived gender differences between men and women. traditionally, the construction and engineering professions have been the dominated by males as opposed to females which resorted to social science and education subjects. it is only in the late 1990s when the government of uganda initiated a deliberate gender affirmative policy, which has seen majority of the females now join traditionally male dominated disciplines. our study involved 21 (15.8%) of the respondents as having been in top management positions, compared to 84 (63.2%) in middle management and 28 (21.1%) in lower management positions. the respondents had different levels of experience in the construction sector. for example, of the 133 study respondents, 65 (48.9%) had experience in central government construction sector, 35 (26.3%) in the local government construction sector while 32 (24.1%) had their experience in both the public and private sectors. results and discussion descriptive analysis results before the multivariate techniques (factor analysis), we examined the descriptive results for 20 variables using means and standard deviations to get the normality of our data. we tested for reliability coefficient and the questionnaire results were found to be reliable (alpha = 0.85) (table 2). nineteen variables were used to measure respondents‟ perceptions on the performance of contractors in the construction sector of uganda. a comparative analysis of the results for each of the items presented in table 2 reveals important information concerning the strength of each of the performance measurement indicator as related by the study respondents. items with a high mean score suggest key areas where contractors‟ performance in the context of uganda is satisfactory and those areas with low means suggest the lowest evaluation by the respondents and in which contractors in uganda need improvement. for example, one of the items with low mean score is on contractors providing adequate training to their employees as a strategy of ensuring success of the construction projects. when respondents‟ opinions were sought on the extent to which contractors in uganda actually provided training to their employees, it was found that the majority of respondents disagreed that this was the practice in the construction sector in uganda. it was found, for example, that of the 102 male respondents, 25 (24.5%) strongly disagreed that contractors provided training to their employees and 49 (48.0%) disagreed suggesting that overall, 74 (72.5%) of the male respondents disagreed that contractors were providing training to their employees. of the 30 female respondents, 22(73.3%) of the respondents also disagreed. this contradicts the findings of beale and freeman (1991) who confirmed that the performance of the project team on construction projects will to a great extent depend on the skills and experience of several key project leaders and once the construction firms in uganda do not invest in improving the skills of their employees, through training, the performance of construction firms will remain poor as demonstrated by the numerous client complaints. respondents who had long experience also shared the above perception. this was for both respondents who had working experience at the central and local government levels. the study found that of the respondents who had less than 5 years of working experience, 30 (75%) believed that contractors were not providing adequate training to their employees. 25 (62.5%) respondents with working experience of between 5 and 10 years, did not support this fact while 44 (77.5%) respondents with more than 10 years of experience, also disagreed. this was a high number of the 53 respondents who were in this category. factor analysis results after examination of the descriptive results, we applied exploratory factor analysis to identify some of the most table 2. descriptive results for the performance measurement indicators. performance measurement items m sd n contractors‟ ability to do the right job first time 3.28 1.35 133 contractors‟ ability to adopt to changes and meet needs 3.28 1.08 133 contractors‟ ability to provide their own resources 3.10 1.20 133 contractors‟ ability to complete work on time 3.10 1.16 133 contractors‟ ability to identify problems and deficiencies 3.37 1.16 133 contractors‟ ability to quickly correct deficiencies 2.68 1.11 133 contractors providing adequate training to their employees 2.15 0.97 133 contractors‟ ability to keep the environment clean 2.83 1.14 133 contractors‟ ability to keep clients‟ facilities clean 2.95 1.12 133 contractors‟ ability to keep work place safe 2.44 1.10 133 contractors‟ ability to avoid wastage of water 2.65 1.17 133 contractors‟ ability to minimize interruptions of operations 3.01 1.06 133 contractors‟ ability to use high quality materials 3.02 1.13 133 contractors‟ ability to restore operations after an emergency 3.04 1.12 133 contractors‟ ability to handle hazardous materials 2.68 1.08 133 contractors‟ ability to adopt to new methods of work 3.20 1.16 133 contractors‟ ability to work as team players 3.33 1.09 133 contractors being reasonable in contract changes 3.08 1.04 133 contractors‟ ability to provide correct documentation and invoices 3.27 1.09 133 important performance indicators critical for measuring the performance of contractors in uganda. in table 3, we present the results from this factor analysis computation. enshassi et al. (2009), in a recent study of the factors affecting the performance of construction projects in the gaza strip, provided a useful categorization of critical performance measures for construction projects. their analysis suggested that the factors which affect contractors‟ performance, included cost, time, quality, productivity, client satisfaction, regular and community satisfaction, people, healthy and safety, innovation and learning as well as environmental. in our study, the factor analysis results loaded on five principal components. the strength of each item in a factor component is determined by its factor loading. the first principal component had five contractor performance measurement items with the lowest factor loading being 0.51 and the highest being 0.70. all the items that loaded on this component had a percentage variance of 27.5%. we noted that all the items that loaded on the component relate to the quality dimensions clients expect from the contractors on a construction project. the study thus concluded that the quality factors are the most important measures of contractors‟ performance in uganda. these results confirmed the findings by enshassi et al. (2009) where quality related factors were found to be important measures of contractors‟ performance. the most important quality performance indicators in our current study include: 1. contractors‟ ability to provide training to their staff as a short and long term strategy of meeting client expectations. 2. the contractors‟ ability to identify problems and then making correction of deficiencies (following specifications). 3. the contractors‟ ability to safeguard client‟s facilities and assets. 4. the ability of the contractors to keep equipments clean (quality of equipment). table 3 results indicate that the second component had three major items with a total variance of 7.8% and their factor loadings ranged from 0.69 to 0.70. the ability of the contractors to do the right job at the right time, ability to provide their own employees and resources, whenever need arose, and their ability to adapt to the changes and meeting clients‟ needs, were identified as the critical performance measures under this component. these factors combined two items under client satisfaction measures and environmental characteristics suggested by the gaza study. the third principle component with a total variance of 7.0% had four items and these were found to be cost measures of contractors‟ performance. the study found that in uganda‟s context, the cost related factors were the ability of the contractors to efficiently use materials, to work as team players (efficiency of human resources), to manage hazardous materials (since their mismanagement would have cost implications) and to keep the workplace clean. the last principle component in our study was 109 afr. j. environ. econ. manage. basheka and tumutegyereize 110 table 3. factor analysis results for the performance measurement indicators. component items 1 2 3 4 5 contractors providing training to their employees 0.70 contractors having ability to correct deficiencies in their work 0.61 contractors having ability to safeguard client‟s facilities and assets 0.60 contractors having ability to identify problems and deficiencies 0.53 contractors having ability to keep their equipments clean 0.51 contractors having the ability to do the right job the first time 0.70 contractors having ability to provide their employees and resources 0.69 contractors having ability to adapt to changes and meet client needs 0.69 contractors having the ability to efficiently use materials 0.78 contractors having the ability to work as team players 0.70 contractors having ability to manage hazardous materials 0.56 contractors having ability to keep work place clean 0.54 contractors having ability to use high quality supplies 0.69 contractors having an ability to restore normal operations after an emergency 0.68 contractors having ability to minimize interruptions to client‟s operations 0.54 contractors being reasonable when it comes to contract changes 0.75 contractors having ability to present correct invoices 0.55 percentage variance 27.5% 7.8% 7.0% 6.4% 5.9% (kmo = 0.801, chi-square = 636.658, sig.0.000). table 4. the most important measures of project performance in uganda. performance measurement variables factor loading contractors‟ ability to use resources efficiently 0.78 contractors being reasonable when it comes to contract changes 0.75 contractors‟ ability to work as team players 0.70 contractors providing training to their employees 0.70 contractors having the ability to do the right job the first time 0.70 contractors‟ ability to use high quality supplies 0.69 associated with environmental measures of contractors‟ performance. on the basis of these components, we extracted the most important measures of contractor performance in uganda as illustrated in table 4. from the analysis of the results, we confirmed that there are a number of key indicators for measuring the performance of contractors in uganda. a deeper analysis of the emerging results suggest that the factors which should be considered for performance measurement of contractors in uganda should have a set of quality, cost, capacity, ethical and environmental related performance indicators (figure 1). contractor performance is judged based on their (i) ability to use resources efficiently, (ii) concern on being reasonable during contract modifications, (iii) ability to structure and work with teams, (iv) ability to continuously improve their internal employee capabilities through training, (v) do the right job at the right time, and (vi) use of high quality of supplies and materials. these are expected of all contractors despite the set of challenges such contractors may face in growing economy like uganda (figure 2). our study found that the industry has not yet been organized to form a registration board like is the case in other east african counties such as tanzania. however, there is an association of contractors that regulates the members (uganda national association of building and civil engineering contractors-unabcec), while the professionals in the industry are respectively regulated through the engineers‟, quantity surveyors‟ and architects‟ registration boards. there is the uganda association of consulting engineers (uace), which is an association that brings engineering consultants and consulting firms in uganda under one umbrella. through this association, members are able to interact and map out solutions to problems facing their industry, carry out joint research and regulate their profession. this helps in keeping the quality of engineering work at its best. the 111 afr. j. environ. econ. manage. figure 1. contractors‟ performance framework in uganda. figure 2. contractor performance. biggest mission of uace is to develop and promote the consulting industry in uganda. uace also helps member consultants to keep current in technology. the association works hand in hand with other technical and engineering bodies to improve the state and to promote the use of technology in the country. conclusion the purpose of this study was to examine the key performance measurement variables for the construction industry in uganda. it was also to identify the challenges faced by contractors in uganda. in this paper, the key basheka and tumutegyereize 112 performance measurement variables in evaluating the performance of contractors in uganda have been examined. a number of opinions from the different stakeholders, knowledgeable in the sector, on the challenges faced by contractors were assessed and a framework matrix on the fundamental challenges faced by contractors developed. it is our contention that the measurement of performance of contractors in a sector which is critical for the country‟s development is essential for policy making, a managerial decision making and, above all, improving the performance of the sector. the paper has discussed key themes of interest to the managers of the construction firms, the client organisations and the policy makers in 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mcconnell et al., 1993; boquet et al., 1995; boquet and breitenbeck, 2000; ali et *corresponding author email: rikhtegar.hossein@yahoo.com. al., 2003). n is required for all stages of plant growth and development because it is the essential element of both structural (cell membranes) and nonstructural (amino acids, enzymes, protein, nucleic acids and chlorophyll) components of the plant. without sufficient n, deficiency symptoms such as stunting, chlorosis, and fewer and smaller bolls are prevalent in cotton (tisdale et al., 1993). also, cotton canopy development is strongly influenced by n uptake (wullschleger and oosterhuis, 1990). during the vegetative stage of growth, rapid expansion of the leaves requires large amounts of n, and both fruit production and retention are dependent on leaf development and photosynthetic integrity (oosterhuis et al., 1983). hearn (1981) found that cotton requires about 90 kg ha -1 n for one bale of lint and about 140 kg ha -1 n rikhtegar et al. 188 for two bales of lint depending upon soil texture. however, n uptake can be as much as 230 kg ha -1 , and n removal at harvest can be as much as half of total uptake. among the plant nutrients, n plays a very important role in crop productivity. it is an important determinant of growth and yield of irrigated cotton (ahmad, 1998). typically, applications of 100 to 215 kg ha -1 n fertilizers are required to optimize lint yield (hussein et al., 1985; constable and rochester, 1988; mcconnell et al., 1995; jin et al., 1997). boron (b) is an essential element that cotton needs during all stages of growth and fruiting. it has been universally recognized as the most important micronutrient for cotton production, and cotton is very sensitive to b deficiency because of its high b requirement (shorrocks, 1992). soil applied b increased cotton yields even when b deficiency was not evident in the plants (anderson and boswell, 1968). it is also essential at all stages of plant growth, and critically during fruit development especially with today’s fast-fruiting, high-yielding varieties. b fertilizers were beneficial to cotton production in sandy and silt loam soils in several parts of usa and africa (murphy and lancaster, 1971; mathews, 1972; roberts et al., 2000). while b is essential for all stages of cotton plant growth, an available supply is most important during flowering and boll development. relatively small amounts of b are required to support the process of growth and development of cotton fibers in the boll. researches showed that as little as 1.12 kg ha -1 of b could increase seed cotton yield by more than 1235 kg ha -1 . b increases the nitrogen and carbohydrate metabolism and sugar translocation in cotton (gascho, 1994). foliar-applied b supplements and soil-supplied b can correct low b concentrations in cotton (heitholt, 1994). foliar application of b accelerates the translocation of nitrogen compounds, increases protein synthesis and stimulates fruiting. as small amounts of b are required, foliar application of b may be more efficient than soil application, especially when deficient conditions are suspected (howard et al., 1998). there are many reports on the growth and yield responses of cotton to soil or foliar applications of b. reports of yield response to soil or foliar applications of b have been contradictory. for example, heitholt (1994) reported no yield response to b utilizing non-buffered spray solutions, whereas howard et al. (1998) observed that buffering b spray solutions to ph 4.0 increased yields relative to buffering to ph 6.0. research in arkansas, usa, has also shown no yield response to soil or foliar applications of b irrespective of soil n status (oosterhuis, 2001). soil applied b increased first harvest lint yields by 9%, and four foliar applications, each at 0.11 kg b ha -1 , resulted in lint yields comparable to soil application of b at 0.56 kg b ha -1 , and doubling the b foliar rate did not increase yields, but the b petiole concentration was significantly increased (howard et al., 1998). lint yield, boll production, flower production, boll retention percentage and fiber properties were not affected by soil or foliar applied treatments. however, foliar b fertilization resulted in leaf blade b concentrations of 154 mg kg -1 without detrimental effects (heitholt, 1994). soil or foliar applied b may not have been beneficial for obtaining high cotton yields. similarly, there were no positive responses to applied soil-b or foliar-b in the high n soil level in any of the five experiments, except for where the low n treatments responded to applied b on a silt loam soil in arkansas (oosterhuis et al., 2000). oosterhuis and brown (2002) reported no effects on yield, fiber quality, boll number per meter, average boll weight, lint percentages, or petiole or leaf b concentrations of soil and foliar applied b treatments observed over three years. no significant effect of b on lint yield, individual boll weight, or petiole nitrate-n level and no significant n and b interactions were found in a regional study conducted to evaluate the interaction of n and b rates on cotton yields (oosterhuis and steger, 1998). in iran, meager researches have been done to study nitrogen (n) and boron (b) effects on yield and quality of cotton, and there are no recommended application rates. as n and b can agronomically and physiologically affect cotton, the main objective of this study was to determine the effect of different application rates of n and b on yield and quality of cotton, and finding appropriate application rates of n and b for cotton production in the arid lands of iran. materials and methods research site this study was conducted at the research site of tehran province agricultural and natural resources research center, varamin, iran on a clay loam soil identified as low in b (0.4 mg kg -1 ) and average in total n (0.07%) for two successive growing seasons (2009 & 2010). the research site is located at latitude of 35° 19' n, longitude of 51° 39' e and altitude of 1000 m in arid climate (150 mm rainfall annually) in the center of iran. weather parameters the mean temperature and monthly rainfall of the experimental site from sowing (may) to harvest (november) during study years (2009 and 2010) are indicated in figure 1. soil sampling and analysis the soil of the experimental site is classified as an aridisol (fine, mixed, active, thermic, typic haplocambids). a composite soil sample (from 36 points) was collected 189 afr. j. environ. econ. manage. figure 1. mean monthly rainfall and temperature from sowing to harvest (mean of 2009 & 2010) table 1. soil physical and chemical properties of the experimental site during study years 2009 & 2010 (0-30 cm depth) date ph ec oc tnv p k fe zn cu mn b soil (ds m -1 ) (%) (%) (ppm) (ppm) (ppm) (ppm) (ppm) (ppm) (ppm) texture 2009 7.3 3.4 0.72 17 10.6 200 4.4 0.90 1.4 12.3 0.4 clay loam 2010 7.6 3.0 0.81 17 9.50 224 5.2 0.42 0.5 11.5 0.5 clay loam from 0-30 cm depth 30 days prior to planting during the study years and was analyzed in the laboratory for ph, ec, oc, tnv, p, k, fe, zn, cu, mn, b and particle size distribution. details of soil physical and chemical properties of the research site during the years of study (2009 and 2010) are given in table 1. field methods a split plot experiment was laid out in a randomized complete block design (rcbd) with three replications to randomize the different n application rates treatments and different b application rates treatments in the main and subplots, respectively. the experiment comprised of four levels of n fertilizer, i.e. 0, 100, 200 and 300 kg ha -1 n as urea and three levels of b, i.e. 0, 500 and 1000 g ha -1 b as boric acid foliar application (without, one time and two time foliar b application). each of the 100, 200 and 300 kg ha -1 n were split into two applications, i.e. one third at pre-planting and two third at pinhead square. application rates were maintained on the same plots by banding application. boric acid foliar was applied with concentration of 0.5% (500 l ha -1 ). foliar b applications began at the first flower stage, and were repeated two weeks after. the control treatment only received water spray. the treatments were carried out on the same plots in the 2009 and 2010 growing seasons. the size of each plot was 12.0 m long and 6.0 m wide. a buffer zone of 3.0 m spacing was provided between plots. in both growing seasons, one of the most commercial varieties of cotton cv. varamin was planted manually on may 5, 2009 and may 7, 2010. plots consisted of 6 rows of cotton planted with row spacing 0.8 m. plots were over seeded and then thinned by keeping plant to plant distance 20 cm, or a population of 62,500 plants ha -1 , at approximately the first or second true leaf stage. management was consistent with typical agronomic practices used for upland production in the region. for all treatments, irrigation scheduling was based on the basis of soil water content monitoring. also, pest and weed control operations were performed based on common local practices and commendations. all other essential operations were kept identical for all the treatments. observation and data collection leaf samples were obtained for n and b analysis one week before first flower and one week after each foliar b rikhtegar et al. 190 table 2. effect of different n application rate on yield, yield components and quality of cotton (mean of 2009 & 2010) n boll seed seed leaf blade n leaf blade b boll cotton lint application number cotton concentration concentration weight * weight yield * rate * yield * * ns -1 (kg ha -1 ) (plant -1 ) (g) of boll * (kg ha -1 ) (kg ha ) (mg kg -1 ) (mg kg -1 ) (g) 0 12.9 c 6.26 b 4.11 b 3642 c 1489 c 2.22 c 56.9 a 100 17.2 b 6.50 ab 4.41 ab 4151 b 1596 b 3.16 b 53.9 a 200 19.8 a 6.90 a 4.49 a 4363 a 1659 a 3.61 b 58.9 a 300 19.6 a 6.80 a 4.47 a 4358 a 1649 a 4.21 a 60.3 a ns = non-significant * = significant at 0.05 probability level means in the same column with different letters differ significantly at 0.05 probability level according to dmrt table 3. effect of different b foliar application rate on yield, yield components and quality of cotton (mean of 2009 & 2010) b seed seed leaf blade n leaf blade b boll boll cotton lint yield application cotton concentration concentration number * weight * weight of * rate yield * ns * -1 ns -1 (g ha -1 ) (plant ) (g) boll (kg ha -1 ) (kg ha ) (mg kg -1 ) (mg kg -1 ) (g) 0 14.1 c 6.15 b 4.48 a 3541 b 1400 c 3.61 a 43.1 c 500 16.8 b 6.49 ab 4.61 a 3991 ab 1562 b 3.43 a 55.0 b 1000 18.1 a 7.02 a 4.52 a 4428 a 1752 a 3.54 a 67.6 a ns = non-significant * = significant at 0.05 probability level means in the same column with different letters differ significantly at 0.05 probability level according to dmrt. application. samples were obtained by removing 20 leaves from the uppermost fully expanded main stem leaves from each plot. after all bolls matured, all seed cotton at 10 meter lengths of the four center rows was hand harvested at approximately 70% open boll for yield analyses. yield was determined by hand harvesting the four center rows from each plot twice and weighing the seed cotton. twenty plants in each plot were randomly selected in mid-september of each year for measurement of number of open bolls. boll weight and fiber data were obtained from 20 hand-harvested boll samples collected from 0.5 m of the two outer rows. lint yields were calculated by multiplying the lint percentage by seed cotton weights. fiber properties for each sample were determined in high volume instruments (hvi). statistical analysis all data were subjected to the analysis of variance (anova) following gomez & gomez (1984) using sas statistical computer software. moreover, means of the different treatments were separated by duncan’s multiple range test (dmrt) at p ≤ 0.05. results and discussion boll number statistical results of study indicated that different application rates of n and b (as foliar b) significantly (p ≤ 0.05) affected boll number (table 2 and table 3). results showed that boll number significantly increased with an increase in n application rate. the highest boll number (19.8) was obtained in case of 200 kg ha -1 n treatment but there was no significant difference between 200 and 300 kg ha -1 n treatments. the lowest boll number (12.9) was obtained in case of 0 kg ha -1 n treatment (table 2). results also demonstrated that boll number significantly increased with an increase in b application rate. the highest boll number (18.1) was obtained in case of 1000 g ha -1 b treatment (two time foliar b application) and the lowest boll number (14.1) was obtained in case of 0 g ha 191 afr. j. environ. econ. manage. 1 b treatment, i.e. no foliar b application (table 3). these results are in agreement with those of oosterhuis and steger (1998) who concluded that n application and foliar b application considerably increased boll number. interaction of n × b was not significant for this trait. boll weight results of study also showed that different application rates of n and b significantly influenced boll weight (table 2 and table 3). results indicated that boll weight significantly increased by increasing n application rate. the highest boll weight (6.90 g) was recorded in case of 200 kg ha -1 n treatment but there was no significant difference among 100, 200 and 300 kg ha -1 n treatments. the lowest boll weight (6.26 g) was recorded in case of 0 kg ha -1 n treatment (table 2). moreover, statistical results showed that boll weight significantly increased by increasing b application rate. the highest boll weight (7.02 g) was recorded in case of two time foliar b application treatment but there was no significant difference between two and one time foliar b application treatments. the lowest boll weight (6.15 g) was recorded in case of no foliar b application treatment (table 3). these results are also in line with the results reported by oosterhuis & steger (1998) that n application and foliar b application noticeably increased boll weight. again, interaction of n × b was not significant for this trait. seed cotton weight of boll statistical results of study indicated that different application rates of n significantly affected seed cotton weight of boll (table 2). results showed that seed cotton weight of boll significantly increased with an increase in n application rate. the highest seed cotton weight of boll (4.49 g) was obtained in case of 200 kg ha -1 n treatment but there was no significant difference among 100, 200 and 300 kg ha -1 n treatments. the lowest seed cotton weight of boll (4.11 g) was obtained in case of 0 kg ha -1 n treatment (table 2). moreover, results indicated that effect of different application rates of b was not significant for seed cotton weight of boll (table 2). although effect of different application rates of b was not significant for this trait, the highest seed cotton weight of boll (4.61 g) was obtained in case of one time foliar b application treatment and the lowest seed cotton weight of boll (4.48 g) was obtained in case of no foliar b application treatment (table 3). once more, interaction of n × b was not significant for this trait. seed cotton yield results of study showed that different application rates of n and b significantly influenced seed cotton yield (table 2 and table 3). results indicated that seed cotton yield significantly increased by increasing n application rate. the highest seed cotton yield (4363 kg ha -1 ) was recorded in case of 200 kg ha -1 n treatment, and there was no significant difference between 200 and 300 kg ha 1 n treatments. therefore, for reaching the highest seed cotton yield use of 200 kg ha -1 n can be recommended. the lowest seed cotton yield (3642 kg ha -1 ) was recorded in case of 0 kg ha -1 n treatment (table 2). the maximum increase in seed cotton yield with 200 kg ha -1 n treatment was about 19.6% as compare to 0 kg ha -1 n treatment. additionally, results showed that seed cotton yield significantly increased by increasing b application rate. the highest seed cotton yield (4428 kg ha -1 ) was recorded in case of two time foliar b application treatment but there was no significant difference between two and one time foliar b application treatments. the lowest seed cotton yield (3541kg ha -1 ) was recorded in case of no foliar b application treatment (table 3). applied b may improve the utilization of applied n by cotton plants by increasing the translocation of n compounds into the boll. a restriction in the flow of carbohydrates out of the leaves could influence the number and size of the bolls. yield increase was the consequence of enhanced boll setting and boll weight. with hot-water-soluble b in our experimental fields being 0.40 mg kg -1 b, the soils were low in b. it is generally accepted that a soil water-soluble b content of approximately 0.15 to 0.20 ppm approaches the deficiency level (anderson & boswell, 1968). positive crop responses to b are attributed to a greater b requirement by cotton as compared with most other field crops (shorrocks, 1992). the maximum increase in seed cotton yield with two time foliar b application treatment was about 25% as compare to no foliar b application treatment. another time, interaction of n × b was not significant for this trait. lint yield statistical results of study indicated that different application rates of n and b significantly affected lint yield (table 2 and table 3). results showed that lint yield significantly increased with an increase in n application rate. the highest lint yield (1659 kg ha -1 ) was obtained in case of 200 kg ha -1 n treatment but there was no significant difference between 200 and 300 kg ha -1 n treatments. therefore, for reaching the highest lint yield use of 200 kg ha -1 n can be recommended. the lowest lint yield (1489 kg ha -1 ) was obtained in case of 0 kg ha -1 n treatment (table 2). results of this study suggested that greater lint yields at elevated levels of n may have been due to the greater number of bolls per plant. these results are in line with the results reported by boquet et al. (1994) that application of optimal n rates may have beneficial effects on lint yield by producing larger bolls at a greater number of fruiting sites. furthermore, results showed that lint yield significantly increased with an rikhtegar et al. 192 table 4. effect of different n application rate on cotton fiber properties (mean of 2009 & 2010) n application rate fiber length ns fiber strength ns fiber fineness ns (kg ha -1 ) (mm) (g tex -1 ) 0 29.6 a 28.1 a 5.2 a 100 29.5 a 28.6 a 5.4 a 200 29.2 a 28.7 a 5.3 a 300 30.1 a 29.1 a 5.4 a ns = non-significant * = significant at 0.05 probability level means in the same column with different letters differ significantly at 0.05 probability level according to dmrt. increase in b application rate (table 3). the highest lint yield (1752 kg ha -1 ) was obtained in case of two time foliar b application treatment and the lowest lint yield (1400 kg ha -1 ) was recorded in case of no foliar b application treatment (table 3). the maximum increase in lint yield with two time foliar b application treatment was about 25% as compare to no foliar b application treatment. the similar results were also reported by anderson and boswell (1968) and heitholt (1994) in field experiments where lint yield increased significantly with an increase in b application rate. yet again, interaction of n × b was not significant for this trait. leaf blade n concentration results of leaf blade chemical analyses showed that different application rates of n significantly affected leaf blade n concentration (table 2). the highest leaf blade n concentration (4.21 mg kg -1 ) was recorded in case of 300 kg ha -1 n treatment and the lowest leaf blade n concentration (2.22 mg kg -1 ) was recorded in case of 0 kg ha -1 n treatment (table 2). oosterhuis et al. (1983) studied the distribution of n in plant components. they found that leaf blade n concentration significantly increased by increasing n application rate. results also indicated that effect of different application rates of b was not significant for leaf blade n concentration (table 2). again, interaction of n × b was not significant for this trait. leaf blade b concentration results of leaf blade chemical analyses indicated that effect of different application rates of n was not significant for leaf blade b concentration (table 2). however, different application rates of b significantly influenced this trait (table 3). the highest leaf blade b concentration (67.6 mg kg -1 ) was obtained in case of two time foliar b application treatment and the lowest leaf blade b concentration (43.1 mg kg -1 ) was obtained in case of no foliar b application treatment (table 3). similar results have been reported by zhao & oosterhuis (2003). they reported that leaf blade b concentration considerably increased with an increase in soil-applied b. once more, interaction of n × b was not significant for this trait. fiber properties statistical results of study showed that effect of different application rates of n was not significant for fiber properties, i.e. fiber length, fiber strength and fiber fineness (table 4). earlier studies found no or inconsistent effects of the n application rate on fiber length (grimes et al., 1969; boman & westerman, 1994). similarly, other researchers found no relationship between fiber strength and n application rate (boman & westerman, 1994; fritschi et al., 2003). also, increased n application rates were reported to have no effect at all on micronaire or to increase or decrease micronaire readings (boman and westerman, 1994; boman et al., 1997). based on 11 years of data, boman et al. (1997) reported that micronaire readings were reduced by applied n in low-micronaire environments and increased by applied n in high-micronaire environments. results of study also indicated that different application rates of b significantly affected some fiber properties (table 5). fiber length was affected by increasing b application and increased significantly. the highest fiber length (31.7 mm) was obtained in case of two time foliar b application treatment and the lowest fiber length (29.2 mm) was obtained in case of no foliar b application treatment, but there was no significant difference between one and two time foliar b application treatments (table 5). although fiber strength was not influenced by increasing b application, the highest fiber strength (28.6 g tex -1 ) was obtained in case of two time foliar b application treatment and the lowest fiber strength (28.1 g tex -1 ) was obtained in case of no foliar b application treatment (table 5). moreover, results showed that fiber fineness was affected by increasing b application and increased significantly. the highest fiber fineness (5.8) was obtained in case of 193 afr. j. environ. econ. manage. table 5. effect of different b foliar application rate on cotton fiber properties (mean of 2009 & 2010) b application rate fiber length * fiber strength ns fiber fineness * (g ha -1 ) (mm) (g tex -1 ) 0 29.2 b 28.1 a 4.9 b 500 31.4 a 28.2 a 5.7 a 1000 31.7 a 28.6 a 5.8 a ns = non-significant * = significant at 0.05 probability level means in the same column with different letters differ significantly at 0.05 probability level according to dmrt. two time foliar b application treatment and the lowest fiber fineness (4.9) was obtained in case of no foliar b application treatment, but there was no significant difference between one and two time foliar b application treatments (table 5). the beneficial effects of b application in enhancing fiber properties were also reported by oosterhuis and steger (1998) and roberts et al. (2000). another time, interaction of n × b was not significant for fiber properties. conclusion for reaching the highest boll number, boll weight, seed cotton yield and lint yield, and enhanced fiber properties of cotton in the arid lands of iran use of 200 kg ha -1 n and 1000 g ha -1 b (two time foliar b application) was found as the most appropriate and beneficial application rates of n and b, respectively. acknowledgment the authors would like to thank eng. mohsen seilsepour at the department of soil and water research, tehran province agricultural and natural resources research center, varamin, iran who generously allowed us to use his research data for this article. the authors are also very much grateful to the islamic azad university, takestan branch, iran for giving all types of support in publishing this study. the financial support provided by the agricultural research, education and extension organization of iran under research award number 10015-24-82-105 is gratefully 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the occurrence, diagnosis and correction of boron deficiency. in proc. intl. symp. on the role of sulphur, magnesium and micronutrients in balanced plant nutrition. (ed. s. portch), the sulphur institute, washington, dc. pp. 39-53. tisdale sl, nielson wl, beaten jd, halving jl (1993). elements required in plant nutrition. in soil fertility and fertilizers. mcmillan publishing co., ny. pp. 48-49. wadleigh, ch (1944). growth status of the cotton plant as influenced by the supply of nitrogen. ark. agr. exp. sta. bull., 446. wullschleger sd, oosterhuis dm (1990). canopy development and photosynthesis of cotton as influenced by nitrogen nutrition. j. plant nut., 13: 1141-1154. zhao d, oosterhuis dm (2003). cotton growth and physiological responses to boron deficiency. j. plant. nut., 26: 856-867. in ternationa l scholars journa ls african journal of environmental economics and management issn 2375-0707 vol. 7 (2), pp. 001-010, february, 2019. available online at www.internationalscholarsjournals.org © international scholars journals author(s) retain the copyright of this article. full length research paper toxic effects of five plant extracts against the larger grain borer, prostephanus truncatus mweshi mukanga1*, yakub deedat2 and felix s. mwangala3 1 mount makulu central research station, private bag 7 chilanga, zambia. 2 department of crop science, university of zambia, p. o. box 32379, lusaka, zambia. 3 national biotechnology laboratories, national institute for scientific and industrial research, p. o. box 310158, lusaka, zambia. accepted 20 october, 2018 dried leaf powders of eucalyptus, guava, neem, tephrosia and water hyacinth were evaluated for their insecticidal activity against prostephanus truncatus horn. the powders were tested at 0.1, 0.25, 0.5, 0.1, 2.5 and 5 g/100 g of dried cassava chips or flour. data was collected on larvae and adult mortality, larvae and adult emergence, antifeeding, and repellency. the effects varied with plant species and dose rate. increased insect deformity and mortality and reduced fecundity were observed among the leaf powder treatments compared to untreated control. the percentage reduction in the adult insect numbers ranged from 37.2 to 99.2% and was highest in the neem, tephrosia and water hyacinth treatments. neem had the highest larvicidal effects though not significant different (p > 0.5) from the other four plant species. on the other hand, tephrosia and guava leaf powders exhibited both strong repellent and anti-feeding effects. the petroleum ether extracts of the leaf powders of neem and guava were highly toxic on p. truncatus. the results suggest that these materials tested have the potential in development of post-harvest protection technology against, p. truncatus, the major pest of stored grains and dried cassava. key words: prostephanus truncates, antifeeding, mortality, repellency, toxicity, leaf powders, petroleum ether extracts. introduction the larger grain borer, prostephanus truncatus horn (coleoptera: bostrichidae), is a serious pest of farmstored maize (golob, 2002; vowotor et al., 2005) and dried cassava (hodges et al., 1985). losses to maize and dried cassava caused by this pest could be as high as 36 – 40% and 70 80%, respectively over a period of 6 months of storage (wright, 1984; golob, 1988). damage of this magnitude is extraordinarily high and demonstrates the destructive nature of this pest, which can threaten food security at both household and national levels (mallya, 1992). the recent introduction and spread of the larger grain borer into africa has increased dried *corresponding author. e-mail: mmweshi@gmail.com. cassava storage problems (schulten, 1996) . hence, effective storage protection strategies are urgently required. current control measures for the p. truncatus include chemical insecticides, fumigation and biological control using of teretrisoma nigrescens lewis (coleoptera: histeridae), a predator of p. truncatus (richter et al., 1997; hell et al., 2006). these methods are expensive and cannot be afforded by the small-scale farmers in developing countries. use of naturally occurring plant materials to protect agricultural products against insect pests is an old-age practice in many parts of the world (dales, 1996; belmain, 1999). obeng-ofori et al. (1996) have indicated that the use of locally available plant materials is a common practice in traditional african communities, mainly for medicinal purposes (herba l use) and in agriculture. extracts from different plants have been known to possess insecticidal properties against a wide range of insect pests (abdullahi and muhammad, 2004). plants with insecticidal properties offer a cheaper sus-tainable alternative to synthetic insecticides, store design, fumigation and thermal distribution methods. they could be an abundant source of locally available pest control agents that can be grown at the village level. the insecticidal specificity of some of the plant extracts and their lack of negative impacts on the food and the environment make them ideal candidates for incorporation into an integrated pest management strategy. exact quantities of botanicals from these plants that give optimum insecticidal effects are unknown. it is thus desirable to quantify the amount of the plant derived materials that provide adequate protection against insect pests and to determine how these affect insect behaviour, growth and reproduction (jilani, 1992). equally, plant species that are found to be effective and popular locally with the farmers need to be subjected to safety testing, at least involving basic toxicological studies (jilani, 1992). the principal advantage of botanicals is that farmers are able to provide their own protectants (isman, 2008). the objectives of this study were: 1. to determine the effect of leaf extracts from tephrosia, tephrosia vogelii; neem azadirachta indica; guava, psidium guajava; eucalyptus eucalyptus globulus and water hyacinth, erchhornia crassipes 2. to test for insecticidal properties of the extracts such as toxicity and morphological abnormalities and 3. to determine whether these extracts could be used as protectants against p. truncatus materials and methods study location the experiments were conducted at entomology laboratory, mount makulu central research station chilanga, zambia (s 15°28’, e28°14’). test plant materials the materials used were dry leaves of tephrosia, t. vogelii hook f.; neem a. indica a.juss; guava, p. guajava l.; eucalyptus e. globules labill. were collected from the field s surrounding mount makulu and water hyacinth, erchhornia crassipes (mart.) solms. the dried leaves were ground and sieved repeatedly to obtain the finest particles using a 300 m sieve. the leaf powders were stored in 10 g glass bottles for later use. ground cassava chips (2 – 5 cm) were used as a food substrate for p. truncatus in all these studies. the cassava chips were sterilized by freezing in sealed plastics for four weeks to kill any residual insect. petroleum ether leaf extract was prepared using soxhlet extraction method. fifteen grams of leaf powder of each plant species were extracted separately 40 60°c for 8 h in 300 ml of the above solvent. the extract thus obtained was filtetred through a sterilized whatman no. 1 filter paper. after which, the solvent was evaporated in a rotary evaporator at 30°c to dryness and the weight of the extract determined. guava leaf powder yielded 251 mg, tephrosia 477.3 mg, eucalyptus 719.7 mg, water hyacinth 196.8 mg and neem 260.4 mg of extract. the extract obtained was then made to different doses that is 0.1, 0.25, 1 and 1% concentration) respectively by acetone. a 1% concentration stock solution was obtained by dissolving 100 mg of petroleum ether leaf extract from each plant in 10 ml of acetone. lower concentrations of 0.1, 0.25 and 0.5% were prepared by further dilution of the stock solution with acetone. test insects adult p. truncatus used in the experiments were reared in 1l glass jars in the protection insectary at mount makulu central research station, chilanga on previously sterilized maize grain at 28 + 2°c temperature and 70 + 5% relative humidity and with alternating light and dark periods of 12 h. the adults and larvae were separated after sieving out the maize. they were placed in different vials for later use. the second-generation adults that emerged were used in all these trials. reproduction inhibition test dry leaf powders were applied as admixtures in six serial doses of 0.1, 0.25, 0.5, 1, 2.5 and 5 g of ground leaves per 100 g of sterilised dried cassava chips. one hundred grams of treated cassava chips were placed in 1l glass jars. the synthetic insecticide, actellicsuper dust (1.6% pirimphos-methyl and 0.3% permethrin) treated dried cassava chips as standard check while untreated cassava chips served as control. actellic super was applied at recommended dosage at 50 g per 90 kg shelled maize grain (mwaya, 1997). the treatments including the control were replicated thrice. twenty (20), 1 3 days old, p. truncatus adults (10 male, 10 female) were introduced in each glass jar. after 10 days, the adults were removed. on the 14th, 28th, 42nd, 56th and 70th day after infesting the dried cassava chips. the number of live, dead and malformed p. truncatus larvae and adults in the ensuing progeny were counted after sieving. the response of the test insects in the treated cassava were corrected using the modified abbott’s formula: 100 (number. of insects in control – number of insects in treatment) / (number of insects in control) henceforth, percentage reduction in the progeny was calculated. a treatment was judged to give complete protection against p. truncatus if no progeny was produced. only the live and normal larvae were returned to the jars. dead and malformed larvae and adults were removed. square root (x + 0.5) transformations were made of the data to compensate for skewness and to stabilise variance before the analysis by anova was done. the total insect counts at each dosage were regressed against the time interval (days) at which insect counts were made, to determine the residual persistence of the leaf powders. the treatments and control were replicated three times for all the experiments. the data from the experiments were subjected to analysis of variance (anova). the separation of means was done by new duncan’s multiple range test (dmrt). significance was taken at 5% level (steel and torries, 1980). repellency effects two and a half grams of treated cassava flour with 1, 0.25, 0.5, 1, 2.5 and 5 g of ground leaves per 100 g dried cassava chips and untreated cassava were separately placed on opposite sides on filter paper, with 10 cm space in between on a plastic petri dish (14 cm diameter, 2 cm height), which served as an arena. ten, 1 2 weeks old p. truncatus adults starved for 48 h were introduced in the centre of the arena using an aspirator. the number of insects found on the treated cassava was recorded twice daily, at 09:00 and 16:00 h, for five (5) consecutive days (dales, 1996). average insect counts for each day were converted to percent repellency (jilani et al., 1992; saxena et al., 1989), which was calculated after gillenwater and mcdonald (1975): % repellency = no. of insects on control half no. on treated half / no. of insects on control half + no. on treated half x 100 anti-feeding study the potency of antifeedant effect of the dry leaf powders was determined using filter paper bioassay. the leaf powder was dusted evenly on both sides of the filter paper (113.1 cm 2 ), in which 1.00 g cassava flour was placed. the leaf powder was applied on the filter paper as proportion of the dose per 100 g to that per 1.00 g dried cassava, that is, 0.001, 0.0025, 0.005, 0.01, 0.025 and 0.05 g. the wrapped cassava was placed in 35 ml vial. cassava flour wrapped in the untreated filter paper served as control. five, 1week-old adults of p. truncatus , starved previously for 24 h were introduced in each vial and left for 7 days. the wrapped cassava served as sole food source. the numbers of holes in filter paper produced by boring insects were recorded at end of the 7 – day exposure period. toxicity effects of petroleum ether leaf extract vapours ten p. truncatus adults (24 – 72 h old) , were placed inside a vial (35 ml) which acted as a gas chamber with a plastic lid in which minute slits were made. a filter paper disc (15.9 cm 2 ) impregnated with the test solution, was suspended from the plastic lid where it was in position by one of the slits in the plastic lid. insects exposed to the acetone impregnated filter paper disc served as control. mortality was recorded after 24 h exposure period. petroleum ether leaf extracts were applied at 0.1, 0.25, 0.5 and 1% concentrations. mortality was confirmed by exposing the insects to a light source and those that did not move were considered dead. insect mortality data were analysed using the polo procedure (russell et al., 1977) using the probit analysis (finney, 1971) to obtain the median lethal concentration of the petroleum ether leaf extracts at 50% kill (lc50). contact toxicity by topical application of petroleum ether leaf extracts the experiment was conducted using the method described by mcdonald et al. (1970) with slight modifications. using a microsyringe applicator, 1 µl of the petroleum ether leaf extracts of selected plant species were applied at 0.1, 0.25, 0.5 and 1% concentrations were applied to the dorsum of thorax of each insect. ten pairs of newly emerged p. truncatus adults were treated with each dose. after treatment, insects were transferred to glass petri-dishes (9 cm diameter, 1 cm height) containing a food substrate – untreated cassava flour. the insects were examined daily for five days; those that did not move or respond to the gentle touch were considered dead. percentage kill of the insects was recorded every 24 h. results effect on larvae and adult emergence the effect of leaf powders on the emergence of larvae and adult p. truncatus are presented in figure 1. results showed that there was between 37.2 to 99.2% reduction in the number of larvae recovered from the leaf powder treatments compared to untreated cassava. the larvicidal effect was of the order: neem leaf powder > tephrosia> eucalyptus> water hyacinth> guava. the percentage reduction in adult progeny in the leaf powder treatments followed similar pattern with the least recoveries occurring in neem leaf powder treatment, followed by water hyacinth. no insect recoveries were made in the standard check, actellic super treatment. there was a preponderance of lower dosages (0.1, 0.25 and 0.5 g /100 g) compared to higher doses (0.1, 0.25 and 0.50 g /100 g) being less effective in reducing both larvae and adult population (figure 2). the regression analysis indicated the existence of a positive linear relationship between insect count and the time interval (days) at which the counts were made (table 2). the strongest relationship occurred in neem applied at 5 g/100 g. the slopes for regression lines at each dosage were observed to be close suggesting similarity in the rate of decay of the leaf powders. effect on larvae and adult deformity and mortality the materials tested significantly affected the longevity or survival of the p. truncatus larvae and adults compared to the untreated control (table 1). the mean number of deformed larvae ranged 0.21 to 0.34 larvae per 100 g dried cassava chips in the leaf powder treatments, while the number of dead larvae were between 0.21 – 0.34. though the analysis of variance revealed no significant difference (p > 0.05) among the leaf powder treatments for larvae mortality and deformity, numerically the highest larvae mortalities were recorded in the neem treated cassava chips. water hyacinth produced the lowest larvae mortality. with respect to the number of deformed and dead adults recovered, no significant differences (p < 0.05) were found among powders of eucalyptus, guava, neem, tephrosia and water hyacinth -treated cassava. however, on average 0.7 to 1.5% of adults in leaf powder treated cassava were deformed, and 1.7 to 3.5% died. this means that leaf powder has exhibited some amount of insecticidal effects and lowered insect reproductivity especially at higher concentrations, 2.5 and 5 g (figure 3) figure 1. mean percent reduction in the number of larvae of the larger grain borer, p. truncatus in dried cassava treated with different doses of five leaf powders after 70 days of storage. figure 2. percent reduction in the number of adults of the larger grain borer, p. truncatus in dried cassava treated with different doses of leaf powder during 70 days of storage. table 1. relationship between total insect count and the sampling interval for different leaf powder treatments. mean number/100 g dried cassava treatment deformed dead larvae adult larvae adult eucalyptus 0.22 a 0.23 ab 0.36 a 0.66 c guava 0.31 a 0.29 a 0.37 a 0.74 c neem 0.34 a 0.01 c 0.39 a 0.34 c tephrosia 0.23 a 0.03 c 0.27 a 0.66 c water hyacinth 0.26 a 0.12 bc 0.37 a 0.69 c actellic super 0.00 b 0.00 c 0.00 b 20 a untreated 0.00 b 0.00 c 0.00 b 0 d mean 0.19 0.09 0.249 3.29 c.v% 29.6 21.7 33.7 32.1 figures followed by the same letter in the same column are not significant different at p<0.05; duncan multiple range test on square root (x+0.5). table 2. mean number of dead and deformed larvae and adult of the larger grain borer, p. runcates in dried cassava treated with leaf powders. mean number/100g dried cassava treatment deformed dead larvae adult larvae adult eucalyptus 0.22 a 0.23 ab 0.36 a 0.66 b guava 0.31 a 0.29 a 0.37 a 0.74 b neem 0.34 a 0.01 c 0.39 a 0.34 b tephrosia 0.23 a 0.03 c 0.27 a 0.66 b water hyacinth 0.26 a 0.12 b 0.37 a 0.69 b actellic super 0.00 b 0.00 c 0.00 b 20.0 a untreated control 0.00 b 0.00 c 0.00 b 0.00 c mean 0.19 0.09 0.25 3.29 c.v% 29.6 21.7 33.7 32.1 (figure 3). the highest insect mortality occurred at 5 g/100 g dried in the guava treated cassava, followed by eucalyptus at the same rate, though not statistically different. no adult mortalities were recorded in the neem treatment at 0.1 and 0.25 g/100 g dried cassava. all the insects in actellic super, died within 7 days of its application while no deformity and mortality were observed in the untreated control. repellency bioassay p. truncatus demonstrated negative orientation response to the cassava powder treated with leaf powder. repellency increased significantly (p < 0.05) with increase in dosage (figure 4). higher dosages (2.5 and 5 g/100 g) were superior to lower dosages (0.1, 0.25, 0.5 and 1 g/100 g). neem leaf powder exerted strong repellency (59.1%). the leaf powder of guava was next best (50.5%). the decreasing order of efficacy of the five leaf powders was as follows: neem>guava tephrosia>water hyacinth>eucalyptus. anti-feeding test the leaf powder treatments produced significantly (p < 0.05) higher anti-feeding effect on the adult p. truncatus than the control (figure 5). among leaf powder treatments, the mean differences were statistically insignificant (p > 0.05) however, the highest feeding deterrence was in the neem followed by tephrosia where the test insects made fewer holes in the filter paper at all the doses. the least effect was in guava. an increase in anti-feeding activity was observed with increasing dose though, not significant different (p > 0.05). figure 3. mean number of dead larger grain borer, p. truncatus adults in dried cassava treated with different doses of leaf powder during 70 days of storage. figure 4. mean percent repellency of leaf powders to the larger grain borer, p. truncatus contact toxicity of petroleum ether leaf extracts vapours the petroleum ether extracts were moderate toxic. the median lethal concentration (lc50 ) of the petroleum ether leaf extract vapours are shown in table 3. neem vapours were the most toxic against p. truncatus adults followed by the tephrosia. the lc50 ranged from 0.384% for neem to 4.027% for guava vapours. vapours from neem were 8 times more toxic to the test insects than those of guava. the confidence limits and slopes of dosagemortality curves obtained indicated no difference in the figure 5. antifeeding effect of different doses of leaf powders on the feeding behaviour of the adults of the larger grain borer, p. truncatus toxicity of neem, tephrosia and water hyacinth. toxicity of the vapours that emitted from the impregnated filter papers on the test insects were of the following order: neem > tephrosia > water hyacinth > eucalyptus > guava. contact toxicity through topical application the probit statistics, estimate of the lc50 values of insect mortality data are presented in table 4. comparison of the lc50 values showed that neem was most toxic (lc50 0.079%) within 48 h after treatment, while guava was the least toxic (lc 50 0.260%). after 96 h, tephrosia was observed to be more toxic extract (lc50 value: 0.033%) followed by water hyacinth (0.036%). at 120 h after application, tephrosia and water hyacinth extracts were most toxic (lc50 0.027%) and least was guava, lc50 value of 0.092%. increased p. truncatus mortality was observed in all five extracts, during the 120 h observational period. the closeness of the dose-mortality curves as indicated by the slopes indicates there were no marked differences in contact toxicity amongst the extracts, except with guava. discussion leaf powders clearly suppressed the emergence of p. truncatus populations in dried cassava chips. the reproduction potential was reduced but not completely inhibited. the effect was observed to be plant-specific and dose-related. several workers (pierce and schmidt, 1992; niber et al., 1994; osiptian et al., 2010; mulungu et al., 2010) have also reported the ability of some leaf extracts to inhibit the reproductive capacity of p. truncatus. the reduction in the numbers of p. truncatus progenies in the leaf powder treated cassava may be attributed to anti-oviposition, delayed egg-hatching and insect growth disrupting effects of the leaf powders. the absence of f1 insects at 14 dat in the leaf powder treatments could have been as a result of these effects. the insect species sensitivity for a same plant extract might be different for different dosages (illoba and table 3. toxicity effect of vapours of petroleum ether leaf extracts on the adults of the larger grain borer, p. truncates. extracts lc50 95% c.l slope + se chi-square df heterogeneity eucalyptus 1.3256 0.678 – 2.72 0.931 + 0.346 1.651 10 .17 guava 4.0279 1.228 – 6.821 0.783 + 0.371 1.940 10 .19 neem 0.3841 0.227 – 0.692 1.138 + 0.327 3.324 10 .33 tephrosia 0.5120 0.331 – 1.058 1.288 + 0.339 6.116 10 .61 water hyacinth 0.5149 0.281 – 0.870 0.824 + 0.321 2.791 10 .28 lc50 = concentration (%) calculated to give 50% mortality, s.e = standard error, c.l=confidence limit, df = degree. of freedom table 4. response of the adults of larger grain borer, p. truncatus to the petroleum ether leaf extracts after topical application. lc 50 extract observational period (h) 24 48 72 96 120 eucalyptus 0.379 0.158 0.083 0.048 0.034 (0.000 ± 3987126) (2.221 ± 0.911) (0.719 ± 0.348) (0.323 ± 0.320) (0.300 ± 0.319) guava 0.573 0.260 0.171 0.108 0.092 (0.875 ± 0.228) (0.775 ± 0.225) (0.806 ± 0.226) (0.788 ± 0.230) (0.739 ± 0.231) neem 0.135 0.079 0.057 0.042 0.040 (0.666 + 0.225) ().767 ± 0.231) ().585 ± 0.232) (0.575 ± 0.235 ) (0.594 ± 0.236) tephrosia 0.189 0.110 0.042 0.033 0.027 (0.737 + 0.224) (0.020 ± 0.226) (0.597 ± 0.234) (0.506 ± 0.237) (0.492 ± 0.239) water hyacinth 0.197 0.105 0.048 0.036 0.027 (0.567 ± 0.222) (0.664 ± 0.226) (0.629 ± 0.233) (0.623 ± 0.236) (0.560 ± 0.240) lc 50 = concentration (%) calculated to give 50% mortality, slope + standard error are in the parenthesis. erakene, 2006) however, physiological responses ought to be noted for different plant extracts. the use of plant extracts powders were observed to be slightly detrimental to the development of later stages of the p. truncates as seen by the low numbers of deformed and dead adults. increased insect f1 population in the leaf powder treatments with time suggests possible readaptation of the adult progeny to presence of the plant extracts and the decay of the leaf powder, which resulted in reduced potency. it was observed that the higher the dose of leaf powders, the lower the numbers of offspring in the subsequent generations. these findings are in agreement with those of akob and ekwete (2007) and nukenine et al. (2010) on sitophilus species. neem leaf powders showed excellent repro-duction and growth inhibitory effect, followed by tephrosia and water hyacinth. the closeness of regression coefficients (steel and torries, 1980) calculated for different leaf powder treatments when regressed against the time intervals at which the p. truncatus counts were made, indicates that the rate of breakdown of these leaf powders was similar. though the relationship was strongest in neem when applied at 5.0 g/100 g dried cassava, the significantly low numbers of p. truncatus recorded in neem treated cassava at each sampling time indicates that neem was more persistent in its effect than other leaf powders. the high p. truncatus populations in the guava and eucalyptus treatments could be a result of the rapid loss in toxicity most probably caused by the strong breakdown of the leaf powders of these two plants that belong to the same genera (sharaby, 1988). the repellency effect of the powders was sustained throughout the study period. the strong repellent effect of this leaf powders admixed cassava may have been largely dependent on olfactory and gustatory sensation (schmutterer, 1990) of the test insects. properties like the repellent odour may have caused the insects to be restless (ogendo et al., 2003). the insects were observed to be turning away and settling on the untreated cassava. the choice for the untreated cassava was because of the repellent chemicals inherent in the leaf powders (jilani et al., 1988). insect repellents are secondary metabolites which have been identified to be alcohols, alkaloids, phenolics, flavonoids and terpenes (dales, 1996). tephrosia leaf powder showed excellent repellency activity followed by neem. in the preference test, the insect were seen to be crawling more towards untreated cassava than leaf powder treated cassava. neem and tephrosia treated cassava were the least preferred food media. the antifeedant effects of the leaf powders might be the result of different kinds of insect anti-feeding allelochemicals (saxena et al., 1989) in the extracts that may have been working together, they deterred the insects from penetrating the filter papers. the antifeeding effect of the leaf powders may have also resulted from the bitter taste that rendered the wrapped cassava unpalatable to the test insects. the neem followed by water hyacinth leaf powders were more effective feeding deterrents. the outstanding effectiveness of neem leaf powders have also been reported by other scientists (saxena, 1993; niber, 1994; 1995; schmutterer, 1990; facknath, 2006; illoba and erakene, 2006). petroleum ether leaf extracts produced considerable high mortality and growth regulatory effects on almost all the treated insects. significantly higher effects were produced by tephrosia, neem and water hyacinth extracts. p. truncatus mortality was dose-dependent, increasing with an increase in dose. the levels of mortality caused by vapour from the leaf extracts were comparably low to those reported on pulse beetle, callosobruchus chinensis by pajni and gill (1991). however, neem vapours were most toxic to p. truncatus adults, followed by tephrosia. in topical treatment, the active fractions in the petroleum ether leaf extracts may have caused mortality by direct interference with insect physiological balance (pierce and schmidt, 1993). the restlessness in the treated insects before death suggests hormonal involvement in the action of these compounds (rani and jamil, 1989). similar observations have been reported for other plant extracts (ogendo et al., 2004). these morphological features may be due to the failure of the wings to expand and flatten after adult insect emergence. the lc50 values of the petroleum ether extracts indicates that tephrosia, neem and water hyacinth displayed the highest potency against test insects while guava was the least toxic. the toxicity effect may be attributed to the secondary metabolites (dales, 1996), which have been isolated from various plant parts. these tend to affect insects in several ways such as disrupting major metabolic pathways and causing rapid death, acting as deterrents, phagostimulants or anti-feedants, or modifying oviposition (jilani, 1992). these secondary compounds may also retard or accelerate development, or interfere with the life cycle of the insects. the differences in the toxicity of eucalyptus and guava to p. truncatus, although, belonging to the same family, myrtaecae, may be attributed to a species-specific factor (kamal et al., 1988). in general, the amounts and toxicity of these compounds in the leaf powders will depends on the maturity of the plants, the season (temperature, photoperiod, and hygrometry) and the geographical and pedological conditions. conclusion besides exhibiting the repellency, antifeeding and reproduction inhibition effects, the leaf extracts exhibited vapour and contact toxicity on p. truncatus. these plantderived materials appear to be effective in reducing p. truncatus infestation. the presence of toxicants and growth inhibitors in these candidate plants suggest good potential for their use in storage pest management especially farm stored grain and pulses. the present findings indicate a piquant toxic nature of neem, tephrosia, water hyacinth and guava extracts on p. truncatus that can be utilized in farm stores against this pest. however, further work is required to investigate the isolation of their insecticidal bio-molecules. references abdullahi ym, muhammad s (2004). assessment of the toxic potentials of some plants powders on survival and development of callosobuchus maculates. afr. j. biotech., 3: 60-64. akob ca, ewete fk (2007). the efficacy of ashes of four locally used plant materials against sitophilus zeamais (coleoptera: curculionidae) in cameroon. int. j. trop. ins. sci., 27: 21-26. belmain sr (1999). final technical report. project r6501. chatham, uk:natural resources institute dales mj 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storage pest management workshop 14-19 april, naivasha, kenya. berks, uk. sharaby a (1988). evaluation of some myrtaceae plant leaves as protectant against the infestation by sitophilus oryzae l. and sitophilus granarius l. insect sci. appl., 9: 465 – 468. steel rgd, torries jh (1980). principles and procedures of statistics. a biometrical approaches (2 nd ed) mcgraw-hill new york. usa, p. 633. vowotor ka, w.g meikle wg, ayertey jn, markham rh (2005) distribution of and association between the larger grain borer prostephanus truncatus (horn) (coleoptera: bostrichidae) and the maize weevil sitophilus zeamais motschulsky (coleoptera: curculionidae) in maize stores. j. stored. prod. res., 41: 498-512. wright vf (1984). world distribution of prostephanus truncatus (horn) p11-16. in: gasga workshop on the larger grain borer prostephanus truncatus (horn) tropical development research institute, storage department, slough. gtz, eschborn, frg. in ternationa l scholars journa ls african journal of environmental economics and management issn 2375-0707 vol. 4 (2), pp. 255-265, february, 2016. available online at www.internationalscholarsjournals.org © international scholars journals author(s) retain the copyright of this article. full length research paper a study of how tall buildings influence climatic factors and the need to create a different microclimate in a district serour abdeslam senior lecturer, architecture department, university of chlef, algeria. e-mail: serour_abdeslam@gmail.com accepted 12 december, 2015 the gradual change of climatic factors in a large agglomeration is primarily related to the expansion of urbanization. the construction of high-rise districts is currently in fashion worldwide, in part because high-rise buildings provide an image of prestige and prosperity for the country. however, the essential purpose of constructing high-rise buildings is to group together a large community in a restricted space. the aim of this study is to understand how tall buildings influence climatic factors and create a different microclimate in the district. this study is based on a 4-year series of measurements of the influence of the high-rise district of la défense in paris, france on climatic factors and air-pollution patterns. the results show that the construction of high-rise district creates a microclimate having higher temperatures than otherwise. thus, high-rises tend to reinforce the phenomenon of urban heat islands. the construction of high-rises also has advantages as shown in this study, the upper-floor quarters benefit from natural air conditioning and a lower concentration of pollution. the construction and management of high-rise districts within cities is thus very important, and can generally lead to ecosystems with microclimates that are more favourable to urban dwellers key words: impact, tall buildings, climatic factors, air pollution. introduction in recent years, there is a very strong tendency to construct buildings that are part of a sustainable development approach. the construction of landmark buildings in major cities around the world is justified by a lack of space and a desire for prestige, prosperity, and the development of architecture and tourism (ingegaèrd, 2000). we are currently witnessing a renewed interest in high-rise districts in major cities worldwide and less interest in green spaces (berkowicz et al, 1996). the construction of a high-rise adds value to the surrounding district. however, the impact of this type of urban development on the climate of the megacities, on public health and urban planning, and on the environment has been the subject of few studies (escourrou, 1981). research in this area is important, if only to minimize modifications of the microclimate and to monitor noxious emissions. the objective of this study is to see the influence of the construction of buildings of great heights and climatic factors on the distribution of air pollution. this article is part of a 4 years long study devoted to “the influence of urban development on the climate and air pollution in the paris region”. to compare the results, several measurement locations were chosen. the point 1 measurement is outside the high-rise towers; the measuring point 2 is located between the high-rise towers and the point 3 measurement is located between parisian buildings with an average of 5-6 floors. we identified these three measurement points which we considered essential to this study as periphery, centre, out of the area. other points have been studied in this long study, but in this article, only these three measurement points are mentioned. to compare the evolution of climatic factors between one place and another, it is necessary abdeslam 256 that the measurement points are the same. these are the three different points (just outside the towers, in the towers, and far from the towers) that show the significant impacts of towers on climatic factors and the distribution of air pollution. in this article, the examples chosen give the best results and an overview of the numerous campaigns of measurement that have been undertaken. the present study, we intended to focus exclusively on the determination of the repartition of the air temperatures, humidity, pollutants surrounding the area towers. this study offers some new elements in order to increase the understanding of the importance of a good planning of the cities on climate and pollution. materials and methods this article is part of a study on "an example of the changing climate due to the constructions in the paris region". this study required an intensive measurement campaign over a period of four years. we tried to see the influence of local amenities on the different climatic factors (temperature, humidity and wind) and the distribution of air pollution. the examples given (average of several measurements distributed over 4 years) refer to the most frequent cases found during our measurement campaigns in different seasons of the year. in this study, measurements of air temperature and relative humidity are taken outside at height of about 1.80 meters with a probe. the final value is recorded on an average of 20 seconds, time it takes for the probe to give the most accurate value. the measurements of the factors climate and the pollutants have been taken in different locations. in this paper, to compare the climatic factors and the rate of pollution in this area, we focused the study on 3 measurement sites. the principle of measurements is to record climatic factors (temperature, humidity, direction and wind speed) and the rate of pollutants (co, co2 and so2) in different places in a district at a period of time with the same apparatus. the device to measure temperature and humidity is a portable air intake. wind measurements are taken with nanometer. the device of measurement of pollutants is a gas detector (the manufacturer of these devices is trotec). in this article, the examples summarize most cases in the measurement campaign. the pollutant measurements are limited to two pollutants: carbon monoxide (co), a colorless, odorless and toxic gas. it is produced during incomplete combustions, sulfur dioxide (so2) emitted from domestic homes and industrial sources. concentrations of pollutants are given in ppm = 2900µg/m3; values are recorded over 20 seconds (time necessary for the conditioner unit of measurement gives an accurate value) at one meter above the ground surface. the wind speed (m/s) was measured with a manometer, the recorded direction is that found with a wire. if variations in measurements are not significant between the beginning and the end at a given point, the estimate is considered exact (few variations of the climatic factors were observed during the measurement process). the apparatus made it possible to compare two recorded values in two different places. the apparatus does not always find the same values as those recorded by weather stations, as recorded and provided by weather forecast of france. others have been published in the monthly departmental bulletins of the paris region, which exist in the library of national meteorology, avenue rapp, in paris. this work provides a new contribution to consideration of spaces to improve the urban climate and mitigate air pollution. the results can be used in future planning of the urban development. results effect of high-rise towers on temperature la défense, in the west of paris, is the first european business district by the extent of its office park. it is located in the hauts-de-seine in the territories of puteaux, courbevoie and nanterre in the wake of the historic axis of paris that starts at the louvre and continues with the champs elysees, the arc of triomphe, and beyond to the bridge of neuilly and the arche de la défense. the architectural ensemble known as the district of la défense in paris (france) is a development model inspired by american urban planning in which high-rise buildings reach significant heights and have glass exteriors (figure.1). the general layout of the neighborhood of défense has been designed according to the principles of the modern movement between 1960 and 1980. this type of district is increasingly common worldwide, especially in large cities of developed countries. the development of this kind of district in the western parisian periphery is certain to have repercussions on local climatic factors. another factor in the strengthening 257 afr. j. environ. econ. manage. figure. 1 view of the la defense and various point of measurement figure. 2 the maximum average air temperatures between the area towers of la défense and the paris centre and expansion of the urban heat island in paris is that this region is one of the most populated in the world. its population increased from 1,35 millions in 1805 people has more than 15 million in 2008 (escourrou, 1981). the intensity of the heat island is proportional to the number of population (escourrou, 1981).central paris has seen its temperature rise because of intense urban development (calvet, 1984), and the temperature increase is especially pronounced in western areas because of the construction of this high-rise district (escourrou, 1981). an examination of the maximum average air temperatures (figure. 2), between the towers of la défense and central paris over a 24 years period reveals that the central paris was hotter when abdeslam 258 table 1. air temperature and humidity around the large high-rise buildings of la défense during cold and hot periods (average of 10 measurements) measurement period tp°c hr % outside tours (point 1) cold period 10,5 60 between towers (point 2) cold period 11 57,8 outside tours (point 1) hot period 23 50 between towers (point 2) hot period 25 45 construction la défense started. during the expansion of this region in the west of paris and the acceleration of urbanization, the defense became hotter than the centre of paris. the construction of the la défense district started in 1970, at which time the maximum average air temperatures in central paris were greater than those at la défense. from 1975 the district of la défense became hotter than central paris, which itself has air temperatures significantly above those of the wider paris region. this island of urban heat that accumulates over major cities (fukuoka, 1983) is due to human activities such as heating and lighting, restitution of diurnal and nocturnal thermal energy stocked in the housing, the capacity to reflect solar radiation. the nonabsorbent ground and the exterior building walls allow the passage of a large fraction of the incident energy, and the accumulation of this energy within the buildings increases its intensity. this phenomenon is well known in cities, especially in summer when the solar radiation flux is greater (eliasson and holmer, 1990). an area that is built up absorbs much more energy (85%) (escourrou, 1995), so the formation of a heat island is understandable, although several urban measurements can reduce the magnitude of the heat island, such as the establishment of green spaces or waterways. these developments are increasingly rare in major cities and new urban projects. the city centre is generally the warmest part of a town throughout the year (kwi-gon-kim, 1989). diurnal energy storage in urban areas by impervious soil and into buildings is restored to the atmosphere especially at night. this phenomenon is very common during summer, when the contribution of luminous efficiency is very important. during cold periods, during our measurement campaigns, the temperature difference between large urban areas and surrounding areas is quite small (average of 10 measurements distributed over 4 years) (table. 1), which is due mainly to the large spaces between towers and consequent breeze circulation, which minimizes the accumulation of heat and the formation of urban heat islands, which minimizes the accumulation of heat and the formation of urban heat islands. knowing that the breeze is a light wind, whose speed is low (1m/s) blowing from a cold to a warm place. this phenomenon is very common in urban areas (retting and al, 2003). outside the high-rise district, the warming effect due to the heat transfer is reduced compared to areas between or very close to the high-rise buildings (nethery, 2007). the outer walls of the facades of buildings are characterized by good thermal insulation. much of the radiating sun is refracted outward participant increasing ambient air temperature (spiller, 1993). the outer sheathing of the large buildings reflects a significant part of the incident solar radiation away from the building, encouraging a temperature increase between the highrises, and the formation of an urban heat island (spiller, 1993). this explains why, during hot periods, la défense becomes hotter than central paris from 9 in the morning to 8 in the evening (figure. 3). in winter, to make towers area more livable, enormous amounts of energy are consumed (heating, lighting and human activities) before being discharged to the outside: the tower district is warmer than in the surrounding area without having necessarily more comfortable. the planner must focus not only on the maps of urbanization but also to the comforts of urban and microclimates generated by the various urban developments, which can have very negative effects. during sunny periods, during our measurement campaigns, the temperature difference between the inside and the outside of high-rises in la défense may exceed 2 °c (average of several measurements distributed over 4 years). this excess of temperature is mainly due to reflection of solar radiation by the outer coating of the glass towers of la défense. indeed, when two environments show significant differences in temperature, a breeze, whose speed is generally less than 1m/s, comes from the cold space to the warm space. these homes have natural air conditioning and are well suited to people that do not support an increase in temperature. the warming effect is felt primarily between buildings (park, 2002), where the wind speed is reduced because of the high-rise heights. in relative terms, the atmospheric humidity outside high-rises is significant. during sunny weather, districts with glass-sheathed high-rises (such as la défense) are more rapidly warmed 259 afr. j. environ. econ. manage. figure. 3 air temperature evolution between central paris and la défense (towers area) during hot periods (average of 4 summers) table 2. difference in pollution levels between a parisian street and la défense (between high-rises) (average of 10 measurements distributed over 4 years) kind of wind between the towers (point2) centre center of paris (point3) co (ppm) 1 9 so2 (ppm) 0,1 0,3 than other areas. the glass-sheathed facades of the high-rises reflect a large portion of the incident solar radiation, contributing to the rapid increase in the ambient external air temperature. the temperature in the district abruptly increases above that of more traditional districts, and the relative humidity decreases (svensson et al., 2002). the air temperature variation as a function of highrise floor level is very large (table.2) (average of 2 measurements). during hot periods, it is usually quite hot on the ground floor of high rises, and the temperature tends to decrease with height (park et al., 2002). the air temperature difference can be quite large during very hot and very cold periods. residences and offices on upper floors are much cooler and therefore consume much less energy in air conditioning. lower floors suffer from high temperatures due to thermal emission into the atmosphere by the non-absorbent ground of some solarderived heat, contributing to raise air temperatures near ground level and a decrease in relative humidity (hicks et al., 1989). the example cited show the difference of air temperatures and humidity in this area. in this city, during the summer months, the sun's rays darts on concrete surfaces, which, in a state of overheating, reflect and trap energy, which is rendered into streets and buildings. so, the city becomes a furnace. the cladding glass buildings reinforced by the concrete of the area, which have replaced the trees and natural vegetation, stores heat (de leeuw et al, 2002). urbanites are obliged to use air conditioners, which consume a large amount of electric power and tend to increase heat stress. in winter, the urban heat island is much more experienced next to the ground. the lower local towers are much more energy compared to the upper floors of premises. the upper floor premises experience much cooler air temperatures than those of the lower floors (faix, 1991). the upper floor premises therefore require slightly more energy for heating. conversely, during hot periods, people working on upper floors enjoy the advantage of cooler air temperatures and, compared with those on lower floors, reduce their energy consumption involved in air conditioning. the tall buildings, vertical construction and towers have been able to identify, as desired by le corbusier, the intermediate spaces in which we have drawn large, wide and straight arteries planted with trees for ventilation and abdeslam 260 figure. 4 average wind direction (number of times) in summer in the paris region (average on 4 years) adaptation to the environment and the local climate. but these areas are extremely hot in summer. in fact, it will be the data climate that must be integrated into the architecture; the solution is in a series of steps on the location, exposure, the thermal behaviour of materials and surface treatment. response of high-rise buildings to wind speed and direction cities are characterised by numerous relatively high buildings. the effect of buildings on winds is a result of their height, their architectural form, and their layout. high-rises affect winds mainly by: reducing wind speed; average measurements taken over a period of 4 years indicate that there is 15% calm wind (zero wind) at la défense between the high rises, compared with 2% in paris suppressing or reducing winds at the building facades, concentrating the air flux in the tight spaces between high rises (venturi effect). towers act as a barrier against the winds on arrival. note that there is also the effect of the state of the weather station. the weather station in central paris is located at the saint jacques tower in a garden and that of defence is housed behind arche of la défense. in summer, prevailing winds in the paris region are generally north. analysis of wind data for summer between la défense and the centre of paris (figure. 4) (average on 4 years) reveals significant changes in direction during a single interval and over a single region. the average wind directions recorded by the meteorological stations at la défense to the west of paris and at saint jacques (central paris) exhibit numerous differences in the summer. the wind at la défense (the high-rise district) is generally from the south, whereas the wind at central paris is from the north or west. the wind direction changes because of the urban morphology (svensson et al., 2002). also noticeable is that, in summer, the high-rise district has the lowest average wind speed of the paris region (figure. 5). this is because the high rises play a significant role in changing wind direction and in reducing wind speed. urbanisation is responsible for the changes in wind direction (won et al., 2003). the deviation of wind directions is related to the urban heat island. this phenomenon occurs more in summer, during the passage of unstable air masses. winds can be deflected in the direction cyclonic (direction of rotation of the earth) to the extent that the roughness increases. analysis of three-hourly data for summer from the fourcity region that surrounds paris leads us to the following conclusions: the high-rise buildings act obstacles to the wind (pelletier, 1987). the wind speed in the high-rise district of la défense is the weakest, which may also be explained by the location and orientation of the meteorological station. the frequency of average wind speeds that exceed 3 m/s is recorded only in the stations of the paris suburbs, with the exception of la défense. these high-rise buildings reduce the wind force and typically create vortices (gomez, 1998). 261 afr. j. environ. econ. manage. figure. 5 average wind speed in summer in the paris region (average on 4 years) note that along the towers, a breeze of wind flows fluently. these breezes are generally low speed: the nanometre indicates zero speed or less than 1m / s. urbanization has certainly influence the speed and wind direction. transformations can occur by piping winds in some streets. when wind direction is parallel to the street, there is usually faster wind speed. if the wind is not parallel to the street, there may be the creation of specific phenomena such as eddies and the reduction of wind speed. the shape and architecture of buildings and their layout also create specific phenomenon, as the acceleration of winds between the narrowed areas facing the wind. the height of buildings and multiplication form a barrier that significantly reduces wind speed effect of high-rise buildings on precipitation it is known that high-rise buildings influence precipitation. as a rule, they are correlated with an increase in rain (givoni, 1989). high-rises increase the surface roughness, which tends to slow the lower layers of the atmosphere, leading to upwells of air and an increase in precipitation (kwi-gon, 1989). comparison of precipitation from 1950 to 1980, 1980 to 1987, 1987 to 1993 and 2000 to 2004 (figure. 6) confirms that only the meteorological station of la défense saw a consistent increase in rain (construction of la défense began around 1970). the construction of la défense clearly led to an increase in precipitation of several millimetres over neighbouring regions. comparison of the average monthly precipitation in the western suburbs of paris (figure. 7) (average 13 years) between la défense, nanterre and colombes (west of paris) leads us to make the following observations: the high-rise buildings receive more precipitation than other outlying areas. for almost the entire year, la défense receives the most precipitation. it is certain that high rise buildings (e.g., la défense) influence precipitation over large agglomerations. the effect of the heights of these buildings on the increase in rain is due primarily to: an increase in the surface roughness: the high rises reduce the wind speed and increase the surface roughness, slowing the lower atmospheric layers and leading to the development of air upwells, which generates an increase in precipitation (eliasson and upmanis, 2000); high air temperatures and low relative humidity as a consequence of the impermeable ground and the restitution of energy into the air, especially in summer . these effects favour instability and air upwells abdeslam 262 figure. 6 annual precipitation between la défense and centre of paris figure. 7 average monthly precipitation in the western suburbs of paris (average 13 years) that trigger storms and an increase in rain (unger, 1999). in large agglomerations, the ground is largely impermeable, so that water which falls quickly flows into drains. trees are rare and evapotranspiration is very limited. it is therefore certain that urbanisation and other human activities modify the relative humidity and rainfall. in general, urbanisation increases precipitation (escourrou, 1995). several factors explain how urbanisation leads to an increase in precipitation: 263 afr. j. environ. econ. manage. high pollution concentration facilitates condensation inside air masses and, in general, leads to acidic rains. high air temperatures, especially during hot periods, facilitate the destabilization of air masses, which triggers rain. urban heat islands act in the same manner. significant evaporation occurs in cites because of the impermeable ground. increased roughness causes a descent of the air mass and a wave system develops: when the air rises there is more rain, when the air sinks, the rain fall. the extension of urbanization on the outskirts of the city changes the roughness that affects the wave system. the construction of high-rise districts increases precipitation. in urban areas, the warm air masses tend to rise. in fact, this type of major construction influences rain because of the significant roughness it causes and by the excessive and rapid heating that is a result of the impenetrable ground and the glass facades. the influence of the unstable and sensitive temperature promotes the rise of air masses. this ascension occurs through thermal gradient, which determines its speed and creates an increase in precipitation. the district of la défense to the west of paris receives more rain than central paris. effect of high rises on the distribution of pollution the design of a high-rise district generally incorporates the notion of green spaces between the high rises. the district of la défense to the west of paris has a low concentration of pollution, because it benefits from its urban morphology: space between the high rises permits air circulation and the ready dispersion of air pollution (touma, 2006). winds are usually winds reduced or stopped by the height of buildings and slowing the wind speed is also linked to increased roughness. the flow of air between the towers is usually a movement of breezes thermal, regional or local, whose speed does not exceed 1m / s. this air circulation is very favourable to the dispersion of pollution between towers in district of la défense. in most of our measurement campaigns, we found low co and so2 concentrations in the district of la défense, increasing markedly in the direction of paris (ingegaèrd, 2000). in winter, variations in the pollution concentration are very small. during cold periods, the distribution of pollution in the morning is similar to that in the afternoon, although the so2 concentration tends to diminish in the afternoon (roussel, 1993). in summer, the pollution distribution is identical at la défense and paris. in spite of the weakness of the wind, the pollution concentration is very small between the high-rises at la défense, but increases considerably toward the traditional districts where space is reduced (sax and isakov, 2003). table 2 shows the distribution of pollution at the high-rise district and a parisian district (average of 10 measurements distributed over 4 years). regarding the vertical distribution of pollution around the high-rises (buildings with over 30 floors), pollution measurements taken ascending a high rise (tour montparnasse, 58 floors) show significant differences in pollution concentrations as a function of floor elevation (berkowicz et al., 1996). pollution is significant at the lower floors because of the dense street traffic (mayer 1999), tending to diminish at the upper floors of the highrise (nethery, 2007). the concentration of the pollutant so2 is very slight for the higher floors compared with the lower floors (park 2002). carbon monoxide, which is very widespread at ground level, diminishes significantly toward the upper floors (borrego et al 2003) (figure. 8) (average of 3 measurements distributed over 4 years). this pollution is mainly due to traffic. these pollutants (co and so2) are mainly concentrated near the ground and that pollution does not rise along the floors of the towers of la défense. the lower floors of buildings receive a pollution rate much higher than the upper floors, especially in the area where winds are generally weak. the distribution of pollution in an urban environment depends on the architectural layout; it also depends on the shape of the arteries, and the proximity of green space. wide spaces between the towers promote the circulation of air pollutant dispersion is better (elvik, 2001). the pollution measurements were made along a tower (tour montparnasse, 58 storeys), to see the distribution of pollution in height. the pollution measurements were made along a tower (tour montparnasse, 58 storeys), to see the distribution of pollution in height. during our measurement campaigns, the distribution of pollution was almost identical. pollution is concentrated next to the ground and tends to decrease in the upper floors. this concentration is due to the fact that at ground level winds are very low and the pollution does not disperse easily. people working on upper floors enjoy a much lower pollution concentration than those working on lower floors or in offices in traditional low-rise districts (williams, 2006). two factors explain the poor distribution of levels of pollution in the area of defence. low car traffic in the neighborhood of defense and the movement of breezes that discharge pollutants into the hottest parts. pollution low in this type of neighborhood tends to concentrate near the ground (waller, 2004). the upper floors, pollution is low due to winds which are more active than the lower floors. ali 073 abdeslam 264 figure. 8 pollution concentration at successive floors of a high rise building (average of 2 measurements, tour montpanasse) discussions and conclusion this study shows that from a measurement campaign in a few points of a neighborhood, it is possible to understand the dynamic behavior of an urban area. this type of analysis shows the interest that could be a campaign of several measurement points, highlighting the microclimate and urban traffic with a cheap hardware. the many examples cited show the role of development in the evolution of climate. the layout plays at various scales: at the local level or variations in temperature, moisture can occur. small breezes are created to promote the regulation of microclimate and pollution dispersion at the regional scale: a district can encourage urban heat island and lead to higher rainfall. good management should avoid heat accumulation and concentration of pollution the study of the microclimate is very complex, but it is essential to limit climate risks in particular the high peaks of pollution. this study leads us to the following results: upper-floor real estate enjoys lower air temperatures in summer, allowing air conditioning to be eliminated or replaced by simply opening windows. high-rises create microclimates by reinforcing the phenomenon of urban heat islands. upper floors benefit from a lower concentration of pollution compared with lower floors, where the pollution concentration is generally quite high. we have also noticed that upper floors suffer less noise pollution than lower floors. the construction of towers in a region plays a significant role in changing local climate. the large spaces between the towers promote wind circulation and therefore the dispersion of pollutants. the construction of high towers increase rainfall and therefore promotes the quality of air in the city. this study provides new information concerning the effect of high rises on the improvement of microclimates, and increases our understanding of the effect of urban development on the climate and the distribution of air pollution. the results may be used for planning for future urban developments. the undertaking of a study devoted essentially to the influence of development and the environment is a significant project. currently, two major concerns for authorities are urban planning and environmental protection, the latter of which is constantly threatened by urban growth, the development of large agglomerations, and the negative effects of air pollution. it is therefore at the local level that human actions carry the greatest weight. this is where people should act to avoid the disastrous consequences of climatic extremes. 265 afr. j. environ. econ. manage. it is also at this level that people should concentrate their efforts and planning to reduce the urban-heat-island phenomenon or eliminate pollution. in coming years, and with global warming, the urbanheat-island phenomenon and air pollution will perturb urban life, and it is then that the urban planner will be held accountable to some extent for the resulting problems. acknowledgement my recognition goes to those who helped me to do this work in paris, france. my sincere haberdashers also go to my supervisor g, escourrou, the entire staff of the meteorological station of paris montsouris and the national library of meteorology (rapp avenue) my thanks also go mainly to o. delvert and those who provided additional data. and my thanks go to all who helped me to do this job. references abdulah r, faried a, kobayashi k, yamazaki c, suradji ew, ito k, suzuki k., murakami m, kuwano h, koyama h (2009). selenium enrichment of broccoli sprout extract 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1022-1037 newman dj, cragg gm (2007) . natural products as sources of new drugs over the last 25 years, j. nat. prod., 70(3): 461-77. ren w, qiao z, wang h, zhu l, zhang l (2003). flavonoids: promising anticancer agents, medicinal research reviews, 23(4): 519–534. sakarkar dm, deshmukh vn (2011). ethnopharmacological review of traditional medicinal plants for anticancer activity, int. j. pharm. tech. res., 3(1): 298-308. african journal of environmental economics and management vol. 1 (4), pp. 076-085, november, 2013. available online at www.internationalscholarsjournals.org © international scholars journals review framework for sustainable development education and lessons learned santosh kumar mishra population education resource centre (perc), department of continuing and adult education and extension work, s. n. d. t. women's university, patkar hall building, first floor, room. no. 03, new marine lines, mumbai 400020, maharashtra, india. e-mail: drskmishrain@yahoo.com. tel: 91 022 22066892 (o), 09224380445 (m), 91 022 28090363 (r). accepted 31 july, 2013 today, educators face a compelling responsibility to serve society by fostering the transformations needed to set the path to sustainable development. the time has come to ensure that the concepts of education for sustainability in the broadest sense are discussed and woven into a framework upon which current and future educational policy is based. understanding the principles of sustainability and the interdependence of the environment, the economy, and social systems can help learn to make the changes necessary to become effective stewards of natural resources and the environment. education for sustainability of which many other disciplines are indispensable components, will engage partners from all arenas adult education, on-the-job training, other formal and non-formal education programs, and the media to reach out to as many individuals as possible. clearly, the time is right to engage in a dynamic process to educate not only children but all citizens about the economic and environmental realities of today’s world. individuals from business and government, the educational community, and non-governmental organizations (ngos) need to come together to share common themes, ideas, and challenges related to education for sustainability. this paper aims to give an insight into the framework within which skills and education can be imparted for environment and sustainability. it also: (a) looks into the significant lessons learnt in implementation of education for sustainable development programmes; and (b) discuses role of students in sustainable development initiatives. the paper concludes that achieving a sustainable future will not happen unless the educational system imparts education for sustainable development to citizens and specialists who understand the interconnections among the environmental, economic and social disciplines. key words: education, sustainability, skill, framework of action, community. introduction education is essential to sustainable development. citizens of the world need to learn their way to sustainability. the current knowledge base does not contain the solutions to contemporary global environmental, societal and economic problems. today’s education is, thus, crucial to the ability of present and future leaders and citizens to create solutions and find new paths to a better future. education for sustainable development (esd) is not a particular programme or project, but is rather an umbrella for many forms of education that already exist, and new ones that remain to be created. the esd promotes efforts to rethink educational programmes and systems (both methods and contents) that currently support unsustainable societies. the esd affects all components of education including; (1) legislation, (2) policy, (3) finance, mishra 076 figure 1. sustainable development and its linkages with social, environmental and economic aspects. (4) curriculum, (5) instruction, (6) learning, and (7) assessment etc. the esd calls for lifelong learning and recognizes the fact that the educational needs of people change over their lifetime. there are many programmes using an esd approach to learning which is critical for achieving sustainability. many individuals and organizations around the world already have implemented several esd programmes through formal and non-formal channels of education cohen (1995). examples of such programmes include: 1. a teacher weaving sustainability themes into primary education using participatory methods; 2. a community development worker raising people’s awareness on rights which are denied to them; or 3. a public health worker training people to draw water from clean sources. this paper aims to give an insight into the framework within which skills and education can be imparted for environment and sustainability. it also: 1. looks into the significant lessons learnt in implementation of education for sustainable development programmes, and 2. discuses role of students in sustainable development initiatives. defining education for sustainability education for sustainability is a lifelong learning process that leads to an informed and involved citizenry having the creative problem-solving skills, scientific and social literacy, and commitment to engage in responsible individual and cooperative actions. these actions will help ensure an environmentally sound and economically prosperous future. sustainable development, as defined by the brundtland commission in 1987, is “development that meets the needs of the present without compromising the ability of future generations to meet their own needs”. in a sustainable society, environmental protection and economic objectives belong to a common framework. in a sustainable world, environmental protection, economic objectives, and social justice should be linked in harmony. the conceptual framework of sustainable development and its linkages with various social, environmental and economic issues can be best understood from figure 1. many educators are helping society achieve sustainability by teaching the three “e’s” environment, economics, and equity along with the traditional three “r’s” reading, writing, and arithmetic. in so doing, they are fostering awareness of sustainability among; (1) individuals, (2) communities, (3) institutions, and (4) governments. in coming decades, education for sustainability has the potential to serve as a tool for building stronger bridges between; (1) the classroom and business, and (2) schools and communities. the esd framework has four major principles which include: 1. promotion and improvement of high quality, relevant basic education; 2. the reorienting of existing education policies and programmes to address the social, environmental and economic knowledge, skills and values inherent to sustainability in a holistic and inter-disciplinary manner; 3. the development of public understanding and awareness of the principles; and 4. the development of specialized training programmes to ensure that all sectors of society have the skills necessary to perform their work in a sustainable manner. dimensions of sustainable development sustainable development is an extension of socioeconomic development, including the environmental dimension. sustainability is the simultaneous fulfilment of the objectives in the three spheres that is, the preservation of ecological integrity, providing social welfare through economic development. these goals can only be achieved through an accurate management of the interfaces between the spheres. the keywords included in the intersections are to be understood as big management guidelines or criteria (peter, 1994). the concept of sustainable development is progresssively recognised by national governments, policy makers and many parts of industry as an important strategy, comprising the following three inextricably linked spheres: 1. environmental sustainability: the environment is mankind’s life support system and includes everything that we rely upon for our existence. this includes air, metals, water, rock and other living organisms. clearly, many of man’s activities are not sustainable and work needs to be done to improve our relationship with the environment. environmental sustainability includes these elements: (1) climate change; (2) air pollution; (3) ozone depletion; (4) oceans; (5) freshwater; (6) wildlife; (7) soil; (8) land use; (9) waste; (10) radioactivity; (11) noise pollution, and (12) light pollution. environmental sustainability rests on the rational use of resources, such as: (1) fossil fuels; (2) nuclear energy; increased; stability promoted; the skills of the workplace need to be improved and workers empowered and rewarded. within this element, there is considerable need for innovation, enabling products to compete on elements other than price. economic sustainability includes these elements: (1) energy; (2) transport; (3) waste; (4) employment; (5) investment, competition and stability; (6) education and skills; (7) business and industry; (8) trade, and (9) tourism. 3. social sustainability: a strong, diverse and thriving social structure is a key element of sustainability. the goal with this element of sustainable development is a sense of social cohesion, cultural inclusion and people empowerment. this is achieved through making meaningful improvements to the places where people live and work, giving them the chance to play an effective part in shaping change for a preferable future. the key elements within the social sustainability pillar are: (1) health; (2) poverty; (3) communities; (4) housing; (5) travel; (6) crime; (7) recreation; (8) consumption; (9) food safety, and (10) stress. sustainable development and environment environment is not only a huge area, but also a huge ecosystem in which millions of creatures live in. environment provides raw material for economy. this raw material gained through the production process turns out to be a consumption product. then, these raw materials and the energy used in production return to the environment as pollution. therefore, sustainability of environment is reasonably important in regards of economical development. in relation to environment, the first comprehensive arrangements concerning international cooperation have been considered in the early 1970s (national science and technology council, 1994). in 1972 in stockholm “united nations human environment declaration” (stockholm declaration), the first global evaluation of many countries whose socio-economic structures and development levels differ from one another, was accepted. sustainable development concept was first defined in 1987 with the brundtland report, prepared by world commission on environment and development and since then began to be widely used. one of the important developments which support the sustainable development vision has come into effect with the 1992 rio earth summit. rio earth summit, the largest meeting including 172 countries, was an important (3) agriculture; (4) livestock; (5) forestry; (6) meeting in which the countries have approved of the biodiversity; (7) water; (8) fisheries, and (9) minerals. 2. economic sustainability: sustainable development encourages people to take a more long-term view of the economy. to make the economy sustainable, it has been argued that more needs to be done with less in terms of the rational use of resources: investment needs to be economic and global issues to be achieved in accordance with the environmental values and sustain-able development principles. some basic principles about the sustainable development which focus on the environmental dimensions are: 077 afr. j. environ. econ. manage. mishra 078 1. humankind is on the centre of the sustainable development. she/he has the right to have a healthy and efficient life in accordance with nature. 2. on condition that they are not disturbing other countries’ environment, all countries save the right to use their natural resources according to their own politics. 3. a development right which meets the current and forthcoming generations’ is necessary so that environment and development should be acknowledged. 4. environmental protection should be seen as a complementary part of development process. 5. in terms of ecosystem protection and development, countries shall cooperate in global association spirit. in environmental protection, countries have common but different levels of responsibility. 6. national authorities, in terms of “the one who pollutes pays it” principle, should make the environmental costs international and the use of economic devices improved. 7. as to activities, which have effects beyond borders, the activist country should inform the related countries in time and provide them with necessary information. briefly, the living environment provided by sustainable development means using of water resources so carefully that current and forthcoming generations can benefit adequately, keeping the weather clean in order to breath fresh air, making use of the benefaction of nature and living in good health ‘today’ and in the ‘future’. the concept of sustainable development is an important milestone in environmental theory because it points how society itself should be organized. this ambitious interpretation is widely shared by business leaders, policy activists, and academics alike. achieving sustainable development through educational approach historically, various conferences and organizations have offered definitions of environmental education (harold, 1992). under some of these definitions, environmental education includes the economic, environmental, and social dimensions contained in the concept of education for sustainability. as attention to the concept of sustainability escalates domestically and abroad, efforts must continue to bring all stakeholders together in its pursuit. the roles of citizens, communities, industry, and government in achieving the goals outlined in recent national reports on sustainability suggest that efforts should be increased to ensure that thoughtful and comprehensive planning is promoted by the formal and non-formal education community. these efforts should focus attention on the delivery systems used to achieve these goals. if sustainability is to be achieved, educators should take a leadership role, breaking new ground to prepare society for an age of accelerating change in a world of: 1. increasingly diverse and growing populations, 2. an expanding economy, and 3. changing global environment. present framework for sustainable development there are various subject areas under sustainable development. these include: 1. health issues and the well-being of people: prevention and control of disease and injuries, as well as the longterm monitoring of the impact of pollution and climate change, are critical to human health and sustainable development. 2. sustainable economic activities and increasing community prosperity: in order to be sustainable, communities must have an appropriate economic base to ensure their survival. 3. education and cultural heritage: these are a fundamental prerequisite for sustainable development and capacity building. 4. children and youth: their well-being and potential are essential to the future of communities and must be protected and nurtured. 5. management of natural, including living, resources: this must be based on sound science and traditional knowledge to maintain and develop local settlements. 6. infrastructure development: this enhances economic growth and the quality of life of people. course for action course of action will require the help of many disciplines focusing on the interconnections among the natural and built environment, and the economic and political forces that influence the world. these forces are fluid and subject to changing conditions. sustainable development is, therefore, a process rather than a fixed goal. vision of sustainability will develop and mature in the future as environmental, economic, and social forces undergo change. the principle that sustainability is a process will need to be reaffirmed continually as nations advance along the path to sustainability (william, 1969). there is recognition that successful efforts for implementing education for sustainability depend on six core themes. collectively, these themes outline a course of action to educate for sustainability. they are; (1) lifelong learning, (2) interdisciplinary approaches, (3) systems thinking, (4) partnerships, (5) multicultural perspectives, and (6) empowerment. lifelong learning education is a process that is or should be – ongoing 079 afr. j. environ. econ. manage. throughout one’s lifetime. as the ontario teachers foundation has stated, learning is not “a prerequisite to living but is its accompaniment”. lifelong learning is the first major theme of the action. “lifelong learning” refers to nonformal education that occurs after one’s formal schooling has been completed. learning is a process that occurs in non-formal and informal ways during an individual's lifetime. all forms of formal and non-formal education are part of the process of lifelong learning. mishra 61 be encouraged as part of non-formal educational experiences. “non-formal education” is used by educators to indicate those forms of learning acquired in informal contexts, such as the media, workplaces, and community activities. all learners both children and adults need to see the connections among discrete bits of knowledge gained on a daily basis if they are to respond to the challenges posed by a nation moving toward sustainability. interdisciplinary approaches education for sustainability requires an understanding of the interdependence and interconnections of humans and the environment. its elements include: 1. knowledge of global socio-geopolitical disciplines, 2. biological and physical sciences, and 3. human socio-economic systems. for example, education for sustainability will prepare policymakers for merging economics and the natural sciences with other disciplines when developing environmental policy. environmental issues traverse studies of the natural sciences (biology, earth sciences), social studies (economics, anthropology, geography, and history), and the humanities (philosophy, the arts, ethics, and literature). many schools have begun integrating environmental examples into some of their coursework, thereby fostering enthusiasm for science and other disciplines (abbey, 1995). ideally, disciplinary courses with social, economic, or environmental content should be accompanied by interdisciplinary subject matter on sustainability, which draws from a number of content disciplines. to the extent possible, educational curricula and pedagogy should reflect the interconnections among disciplines that are central to sustainable development. the benefit of this approach is that sustainability is an ideal organizing theme ideal for encouraging integrative thinking. learning about sustainability necessitates breaking down the walls between disciplines, perhaps by focusing on a single realworld issue addressed from various perspectives. to support this kind of experience, existing education standards may need to be revisited to embrace the major elements of sustainability. whatever the approach, the process used and resources employed to integrate education for sustainability across the curriculum will remain a local issue to be addressed and continually assessed by communities, local and regional programs, and their respective stakeholders. course materials with regionally specific, hands-on examples will have to be developed, and teachers will benefit from training and practical assistance. equally important, interdisciplinary approaches should systems thinking educators generally accept that the first goal of learning is to impart knowledge and the second is to teach skills such as problem solving, conflict resolution, consensus building, information management, interpersonal expression, and critical and creative thinking. education encompassing the concepts of sustainability offers an exemplary vehicle for developing and exercising many of these skills which are increasingly being sought by employers. increasingly, these are the skills that employers are seeking in a world of complex problems requiring integrative solutions. as socio-economic problems and environmental issues become increasingly complex, advanced technologies can serve as a tool helping the human mind synthesize and integrate mountains of data. the importance of systems thinking cannot be ignored. any concept including sustainability should be open to informed debate and sustainable development should not be taught as an ideology or as a goal, but rather as an ongoing process; not as a set of irrevocable answers, but as a way of continually asking better questions. partnerships in addition to bridging disciplines, education for sustainability will mean reaching beyond schools to involve businesses and individuals with specialized expertise throughout the community. in the 21st century, learning about economic and social development as well as the built environment and natural resources will be the collective responsibility of public and private institutions, communities, businesses, and individual citizens worldwide. partnerships among governments, educational institutions (from schools to community colleges and universities), industries, nongovernmental organizations, and community groups are increasingly important. increasingly, businesses require a workforce that is both environmentally literate and skilled in interdisciplinary systems approaches to solving problems. businesses can support formal education by participating in class work as mentors, by offering internships, by providing employees with opportunities for advanced mishra 080 training, and by employing business sites as classrooms. most importantly, the business community and the education profession can engage in ongoing dialogue about common goals and how best to achieve them. national governments can support educational activities in the public and private sectors and build intergovernmental alliances to advance education and training by supporting educational activities. educational institutions should seek ways to collaborate with nongovernmental organizations and industry to advance common objectives. multicultural perspectives to be effective in reaching people across the country and around the world with a message that is relevant and meaningful, education for sustainability must encompass an appreciation of diverse cultural perspectives. this requires that the content of educational materials reflect divergent cultural approaches to sustainability. educational materials and programs should be made accessible to all interested communities. furthermore, educational programs should be rooted in the actual experiences of people in their own communities. these programmmes should not assume a common understanding of sustainability's political and social context. finally, young people from diverse cultural backgrounds must be provided with the training and access necessary to pursue environmental and scientific careers. empowerment education is generally agreed to be the most effective way to impart knowledge and skills that can be applied outside the classroom in everyday life. the desired outcome is informed citizens who are prepared to participate responsibly in a sustainable society. students can be empowered by giving their voice to new ideas and through action, such as voluntary community service, which is, itself an educational tool. non-formal education programs also provide good opportunities for learners to act individually and collectively by providing the knowledge and skills necessary to evaluate and discuss complex issues. education for sustainability can provide a vehicle for engendering responsible citizenship, utilizing a variety of instructional models and guidelines that have been long accepted in the field of education. sharing experiences about successful actions that are engendered by education for sustainability in its formal and non-formal modes will accelerate the transition to sustainability. information about existing models of sustainability can be disseminated through the media, multimedia technologies, information clearinghouses, and other means, both nationally and internationally. sustainability at local level the challenge of sustainability at local level emerged with a new dimension in 1992, in the rio summit, where local governments committed themselves towards sustainability. among the key issues, one that assumed particular importance was the call to create opportunities for wide participation of local actors in the search of strategies and action to achieve sustainability. in local agenda 21 (la21), public participation assumes a fundamental role. it is well known fact that local participants are the ones with the best knowledge of how the local ecosystem and culture are connected together and how they work (julian, 1995). going further, and as the un commission argues, an effective citizen participation in decision making processes helps the promotion of the social and economic equity within among nations. this is a question often neglected that causes the inability to promote the common interest in sustainable development. so, there will be no sustainability without a greater potential for citizens to take control of their own lives, health and environment (http://www.gcrio.org/edu/pcsd/chap1.html, accessed on december 10, 2011). in several countries, it is primordial to find new forms of public participation that promote the effective involvement of the population and create partnership opportunities among stakeholders to achieve common solutions and assure its implementation. however, this cannot be done always in the same way. it is necessary to adapt the participation methods to the population in question, and to its social, economic, cultural and environmental characteristics (jayne, 1995). eco-school project this project is an international project carried out with the cooperation of 14 countries. eco-schools project is a programme carried out to teach in schools about environmental awareness, environment management and sustainable development education (figure 2). with participant approach, students in schools get both information about environmental issues and have an effective role in making their families, local administrations and civil society organizations aware of the environmental issues (rosalyn, 1995). students, in order to help carry out sustainable development process at local level have an effective role in decreasing the environmental effects of school (commission of global governance, 1995). therefore, eco-schools, going beyond the teacher in class, contribute to provide environmental awareness in other parts of the society. study is launched with one of the basic environmental issues like garbage and contaminationwaterenergy and recycling. eco-schools, after studying these three issues for about one or two years mishra 63 081 afr. j. environ. econ. manage. figure 2. eco-schools project. and making sure that the students comprehend the issues completely, can carry on their studies in the subbranch fields like bio-variety, extinct animals, etc. studies carried out throughout the year are scheduled with an activity plan. to carry out studies in accordance with the plan, finding out the false parts and removing with the suggestions are handled by the students. coordinator teacher reports the studies to the national coordinator of project at the end of the year. coordinator evaluates the school’s success by examining the activity plan and the report at the end of the year (unced, 1992). role of students in sustainable development initiatives students by their status constitute one of the most enlightened members of the society. they are in most cases, the youths, full of energy, stamina and innovative skills. as educated people and to whom tomorrow belongs, they have a lot to offer in peaceful co-existence. in general, they are expected to be educators and informants of light and not darkness. their ability to live and work together should have a positive impact on the larger society. each student should: 1. be able to define sustainability. 2. be able to explain how sustainability relates to their lives and their values, and how their actions impact issues of sustainability. 3. be able to utilize their knowledge of sustainability to change their daily actions and consumer mentality. 4. be able to explain how environmental, social, and economic systems are interrelated. 5. learn change agent skills (understands the sustainability issues; can analyze the issues and possible solutions from a systems perspective as well as a personality/group dynamics perspective; and can identify and implement viable solutions to shift the organizational, societal or cultural practices and policies towards sustainability). 6. learn how to apply concepts of sustainability to their campus and community. 7. demonstrate a commitment to sustainability by actively applying their knowledge of sustainability to their lives, professions, and societies. students entering colleges have become increasingly more pragmatic and utilitarian in their approach to education. higher education is seen as a means to social mobility, as opposed to developing a habit of mind that leads one to leadership and service. the vast majority of students entering higher education are more sheltered and conventional than preceding generations. their highly structured lives have been framed by standardized tests and inexperience questioning the status quo. these characteristics coupled with an intense desire to be successful leads to a group of students who are motivated to make change, but lack the direction to do so. an ability to think critically beyond the status quo and utilize this knowledge is critical to their success. employers rely on universities to prepare students for the reality of the world of work. this reality is framed by the mishra 082 triple bottom line. corporations want to be perceived as environmentally friendly, fiscally responsible, and attentive and caring towards their employees and communities. sustainability has become a requisite knowledge area for many industries and careers. fostering student learning and promoting citizenship through the engagement of the disciplines is the philosophical and historical core of education in the united states. in the student affairs profession, this learning (in partnership with a co-curricular context about civic engagement and personal development) prepares students to encounter life’s big questions. in the 21st century, the questions the students encounter include those around; (1) climate change, (2) inequity in how humanity interacts and treats one another, and (3) the inability of present global economic systems and regulations to provide for all people. furthermore, the world student community for sustainable development (wsc-sd) is a multidisciplinary network of motivated students with the ability to think and act both locally and globally, and who share the vision to make a difference. its purpose is to be a leading international student organization that carries out meaningful projects which result in positive and enduring changes that improve lives and communities around the world. the fundamental purpose of the wsc-sd aims to give motivated students, who are passionate about sustainability, opportunities to learn from each other and to collaborate. the wsc-sd hopes to offer students opportunities to get involved and to take action. currently, the wsc-sd is comprised of 10 member student communities, 4 partner student communities and a growing network of individual members internationally. the scope and the nature of the student communities differ just as the personal efforts of the individual members vary. the wsc-sd is making a difference in the world because of the projects being implemented by the members. such projects occur at different levels. currently, countless projects are being implemented by student communities around the world. the main activity of the wsc-sd is to support each other in taking action for sustainability. further, at schools across new york, students, teachers and staff are making a difference in their communities with program to recycle, reduce waste, save energy and conserve resources besides the longrange benefits of good environmental stewardship. sustainability skills include the ability to: 1. consciously contribute to healthy ecosystems through activities such as reducing your carbon footprint, and other initiatives so humans and other species can continue to live on the planet. 2. generate support for change through strong communication skills, consensus building strategies, and with openness to the ideas and struggles of others. 3. articulate clear, strategic, and practical course for changes on our campuses and beyond that will contribute to sustainability. 4. challenge the status quo to achieve transformative change around sustainability. 5. take action on issues and get involved by joining organizations, assess the political, economic, and cultural landscapes contacting elected officials, or simply share information with colleagues, family, and friends. 5. apply effective change agent skills and implement them to achieve sustainability. 6. design sustainable programs, policies, and practices. 7. educate students to be lifelong learners and role models on sustainability awareness, knowledge, and skills. each student should: 1. be able to define sustainability. 2. be able to explain how sustainability relates to their lives and their values, and how their actions impact issues of sustainability. 3. be able to utilize their knowledge of sustainability to change their daily actions. 4. be able to explain how environmental, social, and economic systems are interrelated. 5. learn change agent skills (understands the sustainability issues; can analyze the issues and possible solutions from a systems perspective as well as a personality/group dynamics perspective; can identify and implement viable solutions to shift the organizational, societal or cultural practices and policies towards sustainability). 6. learn how to apply concepts of sustainability to their campus and community. 7. demonstrate a commitment to sustainability by actively applying their knowledge of sustainability to their: (a) lives, (b) professions, and (c) societies. sustainability education should provide faculty and students with an opportunity to explore how their behaviors affect the quality of life of people and other living beings around the globe. it should also emphasize pedagogical learning approaches that are active and experiential, based on inquiry and real world problems. it can be interwoven into all disciplines and can elevate the learning experience to one that is richer in relevance and meaning. lessons learned one lesson learned from the several years of educational efforts aimed at addressing education about the environment is that there is an opportunity for improved collaboration (mindi, 1995). individual roles for each stakeholder are important, but collective action is essential to reduce duplication and leverage scarce resources. 083 afr. j. environ. econ. manage. all sectors of society should work toward complimentary goals so that education for sustainability can achieve its full potential. educators, the private sector, government, and non-governmental organizations (ngos) should evaluate their respective strengths and address how to better coordinate limited resources. awareness of shared needs and common ground is the first step. educators have identified a number of obstacles that are impeding the integration of information about the environment and sustainability in formal learning settings (carol, 1993). one obstacle is that the interdisciplinary content of education for sustainability does not easily fit into a discipline-oriented educational process. other obstacles are the lack of general agreement among professional educators that education for sustainability is a priority and there is insufficient professional preparation for teaching the core content of sustainability issues. until recently, there has been a lack of consensus on an effective system for evaluating programs and materials in order to ensure quality; however, the north american association for environmental education (naaee) has developed material standards for evaluating environmental education curricula (u. s. department of commerce, 1994; goals, 2000). new approaches to learning may offer significant benefits. new approaches will be more readily accepted if the benefits of teaching education for sustainability are understood (u.s. department of education, 1993, 1995). professional training is needed to enable teachers to introduce new curricula and methods into the classroom. still another challenge for educators is finding ways to incorporate diverse cultural perspectives. administrators in universities and colleges should consider adopting sustainable procurement practices and persuade funders to support interdisciplinary research and teaching, which is increasingly needed for finding sustainable solutions (software publishers association, 1995). ngos frequently are faced with the challenge of trying to persuade foundations, businesses, and the public to sustain support for effective programs over an extended period of time, rather than changing focus annually. many non-profit entities, both small and large, have learned that collaborative and synergistic approaches strengthen programmatic initiatives and contribute to longevity and the much-needed financial resource base. business leaders can contribute by working with educators to set priorities to ensure that their support for educational programs is allocated to those that are effective, produce measurable results, and survive long enough to have a real impact. at the same time, companies can participate in mentoring programmes and internships. in the past, the business sector has made a number of indirect contributions to education for sustainability, such as developing innovative systemsoriented approaches to problem solving. in addition to these kinds of contributions, business can finance training for their workers in the use of sustainable mishra 65 technologies and develop innovative approaches to protect the environment and ensure economic prosperity. while there are many successful education efforts underway across the regions of the globe, there is an opportunity for officials to address the lack of effective coordination among the educational activities of individual agencies. duplication of efforts among agencies as well as a steady decline in fiscal support limit efforts to advance education for sustainability (unesco-unep, 1988). in addition, government, the scientific community, educators, and the media should ensure that information provided to the public is accurate, useful and clearly presented. the vehicles, by which information is furnished – ‘internet’, ‘media’, and ‘publications’ are continually changing and require: (1) ongoing training, (2) skill acquisition, and (3) upgrades in equipment (http://www.plotki.net/cms/images/stories/updatedrumour s/sustainble/sustainable_development_education.pdf, accessed on december 11, 2011). conclusion the convergence of a number of trends and events in recent years suggests that a unique opportunity to advance education for sustainability has arrived. on the one hand, the field is benefiting from increased attention from professional societies, continued surges of public concern over local and national and international environmental issues and ongoing engagement by ngos and governmental bodies (rawls, 2001). in addition, the impetus provided by the earth summit and other international efforts, is catalyzing increased public attention to education for sustainability (redford and steven, 1992). this trend is fostering interdisciplinary linkages among the natural and social sciences. achieving a sustainable future will not happen unless educational system involves citizens and specialists who understand the interconnections among the environmental, economic, and social disciplines. today, education for sustainability is positioned to enter the international stage as a priority for the coming decade. taken together, the initiatives and framework offer a starting point. the hope is that the efforts and initiatives will stimulate further dialogue and action. the overarching goal is to infuse the concepts of sustainability into all learning: from structured schooling in formal education settings to lifelong learning in nonformal programs. education for sustainability can help prepare the society and international community for a “fast-paced world of rapid scientific, social, technological, workforce, and demographic changes” (http://wscsd.org/, accessed on december 11, 2011). increasingly, citizens young and old are flooded with information. on the internet, for example, they can find information about: mishra 084 1. global-scale environmental changes like global warming, loss of biodiversity, and the ozone hole; and 2. how human activities contribute to these changes, how they are inter-related and how they affect ecosystems and human health. the most up-to-date scientific information is more readily available than ever before. the key question, however, is whether citizens will be able to understand how to use this information. education is a vehicle that can ensure that technology and the capacity to use information are available to everyone (http://www.tufts.edu/talloiresnetwork/downloads/recasti ngtheroleofyouthinthemenaregionandbeyond.pdf, accessed on december 11, 2011). education is bridge “from the past to the present” and “from the present to the future”. a deep recognition of the importance of education is the necessary first step if the globe is to achieve the level of sustainability. infusing the concepts of sustainability throughout learning experiences will help foster that awareness. involvement of educators, government, businesses, and ngos working toward common goals will lead to an understanding of multiple perspectives and informed decision-making. in true sense, education for sustainability seeks answer to the following questions: 1. what if every person benefited from an education promoting development that is environmentally sound, socially equitable, culturally sensitive and economically just? 2. what if learning was about knowledge and also about doing, being, interacting with others and changing the world? 3. what if formal learning was enjoyable, hands-on and relevant to life outside school while addressing the problems of our world? 4. what if every person benefited from genuine learning opportunities throughout life, in the workplace, and within the community? 5. what if education systems prepared learners to enter the workforce as well as handle a crisis, be resilient, become responsible citizens, adapt to change, recognize and solve local problems with global roots, meet other cultures with respect, and create a peaceful and sustainable society? to sum up, the environmental dimension of the sustainable development is necessary for the continuation of the living life on the earth. therefore, all countries in the world should follow a particular environmental policy. however, in this matter people should also be informed. peoples’ fulfilling of their responsibilities leads to a good deal of development by which the natural life is affected positively like decreasing of energy consumption and preventing environmental pollution. the thing which is necessary for peoples’ awareness is to provide them as citizens who are: 1. environmentally aware, and 2. active participant about environment beginning from primary school. managing sustainable development involves considering interrelated environmental, economic, and social effects and considering policy and programme objectives over an intergenerational time-frame. this integrated and longterm approach is a particularly challenging aspect of managing sustainable development (http://www2.myacpa.org/docs/publications/acpa_sustai nability_monograph.pdf, accessed on april 18, 2012). references abbey r (1995). national environmental education advancement project”, university of wisconsinstevens point, unpublished paper, november carol b (1993). aslanian, trends in adult learning” (new york: the college board, office of adult learning, cohen s (1995). "the warm zone," the washington post magazine, july carnegie-mellon university. commission of global governance (1995). our global neighborhood. the report of the commission of global governance (oxford: oxford university press, 1995). goals (2000). educate america act, h.r. 1804, 1994. u.s. department of education, the goals 2000 act: supporting community efforts to improve schools (washington, dc: government printing office, 1994). harold r (1992). hungerford, investigating and evaluating environmental issues and actions: skill development modules (champaign, il: stripes publishing company. http://wscsd.org/, accessed on december 11, 2011. http://www.gcrio.org/edu/pcsd/chap1.html, accessed on december 10, 2011 http://www.plotki.net/cms/images/stories/updatedrumours/sustainble/su stainable_development_education.pdf, accessed on december 11, 2011. http://www.tufts.edu/talloiresnetwork/downloads/recastingtheroleofyou thinthemenaregionandbeyond.pdf, accessed on december 11, 2011. http://www2.myacpa.org/docs/publications/acpa_sustainability_monog raph.pdf, accessed on april 18, 2012. jayne c (1995). blueprint for a green school (jefferson city, missouri: scholastic, 1995). julian k (1995). national wildlife federation, ecodemia (washington, dc: 1995) mindi (1995). maline, lifelong learning: a conceptual framework”. the national institute on postsecondary education, libraries and lifelong learning. national science and technology council (1994). office of science and technology policy, “technology for a sustainable future: a framework for action (1994). (washington, dc: government printing office. peter d (1994). hart research, goals and priority action projects: environmental education about fish and wildlife conservation”. troy, ohio: north american association for environmental education, rawls j (2001). the law of peoples”. cambridge: harvard university press. redford, k, steven s (1992). “the brief, barren marriage of biodiversity and sustainability”. bull. ecological soc. am. 73(1):36-39. rosalyn m (1995). environmental education literacy needs assessment project: assessing environmental literacy of student and environmental education needs for teachers-final report 1/9/93-95. national consortium for environmental education and training, 1995. software publishers association (october 1995). software publishers association market report (1994-95 school year), education section (washington, dc: october 1995). u. s. department of commerce (1994). bureau of the census, world unesco-unep (1988). international strategy for action in the field of population profile: 1994 (washington, dc: government printing environmental education and training for the 1990s (nairobi & paris, office, 1994). 1988). u.s. department of education (1993). office of educational research united nations conference on environment and development (unced) and improvement, “reaching the goals: goal 5 adult literacy and (1992). local authorities’ initiatives of agenda 21”, “agenda 21: lifelong learning” (washington, dc: government printing office, programme of action for sustainable development” (new york: july 1993). united nations, 1992). u.s. department of education (1995). interagency technology task william b (1969). stapp, the concept of environmental education. j force,technologylearningchallenge (washington,dc: environ. edu. 1:1. government printing office, 1995). 085 afr. j. environ. econ. manage. in ternationa l scholars journa ls african journal of environmental economics and management issn 2375-0707 vol. 6 (2), pp. 413-423, february, 2018. available online at www.internationalscholarsjournals.org © international scholars journals author(s) retain the copyright of this article. full length research paper conflict and resource control in the niger delta: implications for the gulf of guinea region felix ifeanyichukwu igbeke department of political science and international relations, abia state university, uturu, nigeria. e-mail: felix.igbeke@gmail.com. accepted 9 march, 2016 gaps between the definition of expectations, grants of power and verification of accruals from resources, especially oil and gas, tend to undergird the governance processes in most states that comprise the gulf of guinea. these gaps have been responsible for the various problems that have become part of, and which have engendered violence and conflict in the region. as a major stakeholder in the politics and economic strength of the gulf of guinea, nigeria seems to be responsible for the continued crisis in the region. the study, using a coalescence of theoretical explications for understanding the resource-conflict thesis, notes that misgovernance by nigeria as a major stakeholder and one of the most endowed countries in the region negatively affects the wider gulf of guinea region; this negativity is manifested in the now-seeming intractable conflict in the region, and thus makes a case for a thorough understanding of the implications for both nigeria and the wider gulf of guinea region in order to resolve the conflict in the african continent. key words: resources, governance, conflict, gulf of guinea, niger delta, nigeria, oil and gas. introduction the major problem of the african continent and west africa in particular, can be succinctly stated to be that of misgovernance – either at the political, economic, social or cultural levels. governance relates to decisions that define expectations, grant power, or verify performance in terms of accurate account of accruals from resources. it consists either of a separate process or of a specific part of management or leadership processes. sometimes people set up a government to administer these processes and systems. it is thus the authority for defining policy, providing leadership, and managing and coordinating the procedures and resources that ensure security; the set of authorities, processes and procedures guiding strategic and key operational decisions made for the enterprise that is the state or government. it clarifies relationships and responsibilities among the entities making up the enterprise. governance in its widest sense refers to all the processes, systems, and controls that are used to safeguard and grow assets in social organisations. according to adeyeye (2007: 32), governance refers to the use of politics, economic and administrative authority and resources to manage or exercise control over the politics and resources of a given society. thus, misgovernance in the context of this paper involves the accumulated issues of misappropriation of resource wealth by government or in some cases the inability of government to ensure that resources accrued for government and people are used appropriately for the good of the populace. in nigeria, misgovernance is epitomized by the crisis in the niger delta, which gained ascendancy as the various problems in the region began to acquire a seemingly intractable nature. the plethora of literature on this region and its recurring crisis (obi, 1997, 2001, 2009; ibeanu, 2000; bannon and collier, 2003; de barros, 2004; douglas et al., 2004; humphreys, 2005; collier and hoeffler, 2005; ikelegbe, 2005; omeje, 2008; asuni, 2009; basedau and lay, 2009) point to the dialectics of resource governance as the incubator of internal conflicts in the entire gulf of guinea region comprising nigeria, gabon, cameroon, chad, equatorial guinea, angola and sao-tome and principe. this study focuses on nigeria‟s niger delta to x-ray the implications of misgovernance for the security policy of the gulf of guinea region. the growing interest in the gulf of guinea region derives from its endowment of lucrative vast deposit of good quality oil and gas resources aside from other marine resources the igbeke 414 region has to offer (ly, 2010). international oil politics now is more or less fundamentally about gulf of guinea oil and natural gas deposits, and control of the corridors for transporting it; and this is mostly because of the volatility of the middle east and the proven high quality of the oil that comes from the west african and gulf of guinea region. nigeria, the greatest source of african oil for export, is at the centre of the african oil-producing states bordering the gulf of guinea, and the niger river is the corridor for transporting not only nigerian oil and gas [but also] oil and gas from landlocked niger as well (garrison, 2009). according to delano (2009: 3), over the last ten years, the gulf of guinea has emerged as a maritime hotspot with regional oil, natural gas, and rare mineral deposits, thereby drawing interest from every part of the globe. the true significance of the region, however, rests in its oil reserves and is fundamentally the prism through which most outside actors view it. the amount of oil the area can provide is estimated at roughly 54 billion barrels, just about 5% of the world‟s proven reserves, of which 80% belongs to nigeria and angola. although 54 billion barrels seems miniscule, there is universal confidence that this number is an underestimate. with current production nearing 4.5 million barrels a day and expected to reach the 7 million mark by 2010, the region‟s energy production is rapidly increasing. according to egbogah (2010), the gulf of guinea has about 10% of global energy, and is a largely unexplored basin. nigeria is a dominant force in the gulf of guinea region of africa. with 46% of the gdp of the sub-region, a high demographic size and huge deposits of oil and gas resources in its niger delta region (egbogah, 2010), it is proper that any research on the conflict situation in the gulf of guinea should be started with nigeria; and there is no other place to situate it than in the volatile niger delta region. this is very important given the fact that the problem of the niger delta affects everything that nigeria and africa stand for generally. the problematique the niger delta is strategic and a crucially important point of departure in virtually all discourses on the nigerian state and the entire gulf of guinea region. over the decades, the region has engendered a lot of interesting debates, workshops, symposia and conferences as a result of the various governance and security challenges bedeviling the region. these activities have centred mostly on the control of the rich oil and gas deposits in the region and the manner of their exploitation, being the mainstay of the nigerian economy. however, the modes of exploitation and utilization of the proceeds from the sale of these natural resources have caused instability in the region and nigeria generally. familiarity with the literature on the subject matter indicates that the internal conflicts in the oil-rich region of the gulf of guinea are as a result of many factors, some of which are that the struggle for the control of oil and gas resources increases the region‟s vulnerability to conflicts; greed for economic gains is the primary motivation for resistance and struggle for the control of oil and gas resources; there is profiteering from the struggle. community leaders, warlords and traders profit from the oil and gas-related conflict situation in the region and so stoke the embers of the crisis for private-regarding interests; warlords characterize the insurgency, rebellion and militancy in the region in such a manner that they become the subject of discourse which gives them bargaining power; there is high level of economic and financial crimes involved in the struggle for the control of oil and gas resources in the form of pipeline vandalization, piracy, oil bunkering, small arms proliferation, hostage-taking and kidnapping; and government‟s militarization of the region gives the sense of insecurity and people therefore feel constrained to take up arms against government forces; and the inadequacy of the democratic institutions in nigeria means that there is little accountability and transparency in the management of revenues accruing from the exploitation of natural resources in the region (ikelegbe, 2005). with the above information which ordinarily seem to have covered virtually all the aspects of the niger delta problem, undertaking another research on the region seems unnecessary. however, owing to the fact that the niger delta is still volatile and prone to violence and conflicts despite all the developmental, intellectual and financial resources it has received, there is need to explore the link between oil and gas governance and conflicts in the gulf of guinea focusing on the niger delta region of nigeria. the reasons being given that the answers to the niger delta problem as regards oil and gas governance are already known but the lack of political will being the problem is defeatist as long as the problem is yet unresolved, and as long as it is becoming hydra-headed and octopoidal in nature. and given its strategic importance to the gulf of guinea, only a concrete resolution of the conflict in the region would make meaning. theoretical explanations for the synergy between resources and conflicts there is a correlation between oil and conflict that suggests causation. although scholars have always tried to use the three major counter-examples of botswana, namibia and south africa as mineral-dependent african countries that do not suffer from this symptom (mokhawa, 2005: 21; paes, 2005: 305–23; omeje, 2008), and a few other big success stories of rich oil-producing countries like norway, the united arab emirates and the sultanate of brunei, does not mean that the thesis is wrong or can 415 afr. j. environ. econ. manage. be ignored. thus, there are several theories about how oil fuels conflict that emerged out of large-number of quantitative studies that found strong correlations between oil dependency and various kinds of violence. humphreys (2005) outlined six rival families of mechanisms that could explain the relationship between natural resources and conflicts: (a) the greedy rebels mechanism; (b) the greedy outsiders mechanism; (c) the grievance mechanism; (d) the feasibility mechanism; (e) the weak states mechanism; and (f) the sparse networks mechanism. in the greedy rebels‟ mechanism, the booty character of natural resources motivates rebels to take up arms and/or continue fighting. this mechanism has three variants. in the first variant, domestic groups may engage in quasicriminal activities to benefit from resources independent of the state as exemplified by piracy, oil bunkering and kidnappings going on in the niger delta region. in the second variant, natural resources increase the prize value of capturing the state. this means that either variant could lead to either situation taking place – weakening the state in order to make its capture possible. the third variant states that if natural resources are concentrated in a particular region of the country, it makes for the possibility of that region thinking it could secede from the rest of the country, and that it would be possible to withstand the pressure and become prosperous. in the greedy outsiders‟ mechanism, greedy outsiders might be ready to intervene militarily – either directly or through support for internal conflicting factions in order to gain or maintain control over lucrative resources. the existence of natural resources may be an incentive for third parties – state and corporations – to engage in or indeed foster civil conflicts, as seen and proved in the niger delta with the involvement of shell bp in the ogoni crisis, for which they have paid huge sums as compensation to the people. in the grievance mechanism, perceived deprivation of producing regions and social groups create grievances and trigger violent uprising, especially secessionism in producing regions. natural resource dependence can be associated with grievance rather than greed. this is because countries that depend on resources may experience transitory inequity as part of the developing process; such economies may be vulnerable to terms of trade shocks, that is, they may likely be dependent on a small number of commodities for their export earnings; the process of extraction may produce grievances, either through forced migration or as a result of the environmental damage or loss of land rights; or natural resource wealth may be seen to be unjustly distributed as seen in the case of the niger delta. in the feasibility mechanism, natural resources provide the means for rebel finance. natural resources could provide a way to finance rebellions that have been started for other reasons, thereby increasing the prospects of success. this can be done either through control of production during the conflict or by raising revenues in advance to gain control of the resources “booty futures” (ross, 2002). in the weak states mechanism, resource abundance reduces the quality of state institutions, and makes internal violent conflict more likely. state structures may be weaker in natural-resource-dependent economies; and this argument focuses on the strength of the linkage between the state and society. this argument means that when citizens are not taxed by governments, they have less power over them as they would have less information about government activity, weaker incentives to monitor government behaviour, and fewer instruments at their disposal to withdraw support from governments. accordingly, resource-dependent states may have little compulsion to respond to the demands of their citizens or create structures that engage their citizens (collier and hoeffler, 2005: 512). conversely, governments that rely on natural resources rather than on taxation have weakened incentives to create bureaucratic institutions. that is, such states are likely to have weak structures because they have less need for intrusive bureaucracies to raise revenue; and as such, the domestic economy is divorced from the state. in the sparse networks mechanism, rentier economies have a one-sided integration in the world economy and hence cannot develop thick terms of exchange conducive for peace and stability. the importance of natural resources may lie in their impacts on the daily economic activities of the citizens of an economy and how these in turn affect attitudes of citizens or relations between citizens. thus, natural-resource-dependent economies may have weak manufacturing sectors and correspondingly low levels of internal trade. this is because it is a given that trade is associated with relationship and cohesiveness among people. no one fights his trading partners as wherever there is commerce, manners are gentle. moreover, through trade, partners understand one another‟s cultures and this helps in reducing the risks of conflicts between them. given the above theoretical explanations to buttress the fact that there is a synergetic linkage between resources and violence or conflict, this study hypothe-sizes that the niger delta conflict is a consequence of the nigerian state‟s inability to have a coherent resource wealth governance policy. nature and character of resource governance and dynamics of conflicts in the niger delta governance of oil wealth has always been related to the management of the resources of the nigerian state. the concept of resource management is closely tied to that of resource control as the latter “…largely deals with the igbeke 416 need to regain ownership, control, use and management of resources primarily for the benefit of the communities and the people on whose land the resources originate, and secondarily, for the good governance and development of the entire country” (douglas et al., 2004: 7). resource-rich nations like nigeria, and especially in the developing world, have always had the central government taking over the management of resource wealth. nigeria‟s oil and gas resources are controlled by the federal government which then issues oil exploration and production right to corporate partners in exchange for a share of profits, as well as joint ventures with multinational oil corporations (mnocs). poor management of resources, as noted by onigbinde (2008), has been responsible for the niger delta debacle. she notes that many decades of neglect of people in the region while corrupt and repressive governments kept amassing unimaginable wealth from the proceeds from the area led to the marginalized groups seeking to redress the injustices and inequities in resource distribution. thus, insurgency became their inherent method of showing their grievance for a change in the system. she goes on to show that with the nigerian government‟s sole ownership of oil and gas wealth via the petroleum act of 1969, offshore oil revenue act of 1971 and land use act of 1978, with which government entered into a 50-50 joint venture agreement with shell in the 1950s, and which the government has refused to change after more than 50 years despite the injustice of the landowners not getting anything, helped to trigger the niger delta conflict. the implication of the land use act of 1978 is that “the title to any land where oil is found is automatically transferred to the federal government without adequate compensation to the landowners” (bisina, 2004, july 29). moreover, the government has over the past five decades been on the side of the mncs whom it collects rents from, such that decisions on oil and gas resources are made directly between government and the mncs, shutting out the people, who feel alienated and want to show their grievance. this hobnobbing with government has always given the mncs the opportunity of getting things done their way. according to obi (1997: 10-14), oil multinationals feed the nigerian state giving room for an unequal partnership formalized through three types of joint agreements in the oil industry – the joint venture agreements, production-sharing agreements, and risksharing contracts. thus most of nigeria‟s oil is produced by oil companies as “operators or technical partners” of the state. basedau and lay (2009) contradict the long-held beliefs in the resource curse theory which has been linking the extraction of natural resources to corruption, authoritarianism, economic decline and conflicts, and state, however, that “resource-conflict link is more complex than conceptualized in the scientific mainstream.” they also note that the rentier state theory which identifies economic stagnation, corruption and authoritarianism as part of the political economy of resource-rich states goes contrary to the resource curse theory in the sense that “governments use abundant resources to buy off opposition or suppress armed rebellion, thereby contributing to political stability and preventing armed conflicts (basedau and lay, 2009: 758). their arguments are that very high per capita revenues from oil allow governments of resource-rich countries to avoid conflict and maintain peace by a combination of large-scale distribution, high spending on the security apparatus, protection by outsiders and relatively more favourable state institutions. collier and hoeffler (2005) note that “large rents are not intrinsically a curse; they obviously have the potential to accelerate peaceful development, and this potential has occasionally been realized, as in botswana … clearly, in some circumstances resource rents induce or prolong conflict, and in others they do not” (2005:627). they go further to state that not only can resources finance conflict, but it can also induce patronage politics and motivate conflict, especially in the form of secessions, as currently being seen in the niger delta region of nigeria. as they noted: there is now a case for extending controls to oil: in the delta region of nigeria, large-scale organized crime is bunkering oil from pipelines to the scale of around $1 billion per year, selling it in east asia. there is obviously scope for this massive criminal activity to link with the political secessionists of the delta region. as noted by omeje (2007: 46), oil-related rents (royalties, taxes, oil export earnings, interests on joint venture investments, etc.) are the lifeblood of nigeria‟s economy. the domestic budget and the huge import trade sector are mainly financed by oil revenues. factions of the country‟s elite, with strong interests in the allocation, appropriation, and use of oil revenues, dominate all levels of government. their interests conveniently combine with those of the state to support a regime of predatory accumulation and lawlessness… thus, the actions of some tnocs – insensitivity to the local environment; destruction of biodiversity; inflation of contracts, imports, and supplies; and collusion with state officials to subvert tax and investment policies – are made possible by the accumulation climate encouraged by the rent-seeking political economy. according to volman (2003: 1), the possession of oil resources, and the revenues that accrue to governments from the exploitation of this resource, has had a decisive impact on the security and stability of nearly every african country that has significant amounts of oil. this has been true in the past and oil is certain to have a similar impact on those countries where it is only now being discovered and exploited. countries without oil certainly can become militarized 417 afr. j. environ. econ. manage. and experience conflict with their neighbors or serious internal violence, but the possession of oil resources has unique consequences for national security and internal stability. this is due to the special characteristics of oil production. on the one hand, oil production is capital intensive; it can only be undertaken only by companies willing to invest immense amounts of capital and, thus, requires the cooperation of central governments willing and able to protect these large foreign investments. on the other hand, oil production yields vast revenues for african governments. this allows them to make large arms purchases, to build up their military forces, and to strengthen internal security forces. however, it also can lead to internal political conflict and violence because it increases the stakes of political competition and encourages rival leaders and parties to resort to the use of force to gain control of the oil revenues. moreover, because oil revenues are managed by central governments that are often neither democratic nor financially transparent, the money generated by oil production often does not contribute to national economic development, but is instead diverted into the bank accounts of government officials or used to finance unnecessary prestige projects. the misuse of oil revenues exacerbates political discontent and can provoke internal political violence. finally, because oil production is often carried out with few, if any, environmental controls, it can have a devastating effect on people living in the oil-producing areas, thus further aggravating public unrest. as the following cases illustrate, oil production does not always cause militarization and violence, but it usually has a negative impact on the security and stability of those countries that have large oil resources. talking about institutional weaknesses of resource-rich states and the linkage with the performance of their governments, postali (2009: 208) notes that countries with abundance of resource wealth exhibit problematic fiscal policies and small levels of domestic savings in which case the resource rents are wasted in financing ordinary governmental expenses. perhaps the most contentious role of the nigerian state relates to the sharing of oil revenues. at its heart is the feeling that oil wealth from the niger delta has been used largely for developing other parts of the country or taken abroad, while the “goose that lays the golden eggs” has been neglected and underdeveloped. this is based on the policy shifts in the allocative principle that national revenues should be shared on the principle that resources should be returned to the site of their generation on the basis of the ratio of their contribution to the national purse. the argument is when regions that covered with ethnic majority groups produced the bulk of national revenues they enjoyed the derivation principle which ensured that they retained the bulk of the wealth generated within their regions. since the end of the civil war in 1970 when the bulk of revenues came from oil from the ethnic minority region of the niger delta, derivation was increasingly reduced from 50 to 3% in the 1980‟s and only increased to 13% in 2001. the domination of the oil wealth produced from the region by non-deltans has also fuelled resentment and anger amidst claims that the oil of the region is being stolen by other groups, leaving the source of the wealth to wallow in paradoxical poverty (douglas et al., 2004; watts, 2008; ebeku, 2008: 400-403; asuni, 2009). according to osuoka (2007), petroleum exploitation in the niger delta region of the country has mainly been carried out by transnational companies that operate joint ventures with the federal government. with this arrangement, oil and gas revenues and taxes are paid to the federal government. a system of revenue sharing exists whereby the federal government transfers some petroleum revenues to all the 36 states and 774 local government councils in the country. under the arrangement, an attempt is made to pay 13% of petroleum revenues as derivation fund to the oil producing states as stipulated by the 1999 constitution. however, the fate of revenues and the derivation fund has continued to be a source of controversy and tension between the federal government and the state governments. the general understanding is that a federation account exists to which oil and gas revenues are paid with a revenue sharing formula existing somehow as follows: federal government, 52.68%; states, 26.72%; and local governments, 20.60% (osuoka, 2007: 58). thus, the dynamics of violence in the niger delta are best understood when put through the test of the conditions and contextual factors that accentuated them. according to mahler (2010), some of them are: oil dependence and abundance this means that the amount of oil is not increasing as the number of the population and the fact that other states in africa have also discovered oil thus making nigeria not the only country that is looked upon by the international community for oil and gas resources. thus, she notes: this low per capita oil wealth can be considered to be one of the factors explaining why oil in nigeria cannot have a stabilizing or conflict-reducing effect comparable to that in oil-exporting countries such as saudi arabia or kuwait. moreover, the substantial decline in oil revenues in the 1980s and 1990s can also be viewed as having contributed to an increase in the potential for conflict (mahler, 2010: 15). resource management and economic distortions there is ample proof that oil and gas resources in nigeria are not well managed. this has resulted in oil spillages igbeke 418 that are not taken care of, not by the multinational oil corporations nor by the nigerian government. again, nigeria is one of the major gas flarers in the world (second after russia), and this poses environmental challenges to the region. moreover, the manner of distribution of resource wealth leaves much to be desired and this has fired the resolve of the niger delta people to fight for their rights to be taken seriously as they wallow in poverty when there is abundance under their feet. the combination of these factors ensures that the violence in the oil-rich niger delta continues. thus, mahler states that: poverty had been prevalent in nigeria before the “oil era,” but it increased drastically in the context of the declining oil revenues in the second half of the 1980s, the economic crisis, and the structural policy reforms, all of which were related to the ineffective and unsustainable resource management. the percentage of the population living in extreme poverty rose from approximately 35% in 1970 to 70% in the middle of the 1990s (mahler, 2010: 17). geographic location of resources within the country the geographical location of the niger delta region makes it inaccessible; it has marshes, creeks and dense mangrove forests. this makes it easier for oil spills, bush burning due to gas flaring and contamination of drinking water to affect the region easily. to further underscore the point being made, as it relates to the entire gulf of guinea region, mahler (2010: 19) states as follows: deep offshore oil production in the gulf of guinea has only recently become more relevant. today this offshore production represents about 15% of nigeria‟s total oil production. offshore exploitation is far more expensive; nevertheless, it has become more attractive to multinational oil companies in the context of the increased attacks on oil facilities in the niger delta. although the attacks on offshore oil platforms by the movement for the emancipation of the niger delta (mend) in june 2008 showed that offshore oil production is not beyond the reach of militant aggression, offshore operations are still markedly less vulnerable than operations in the delta. a further shift of oil production into the gulf of guinea could moreover at least somewhat reduce the grievance related conflict potential, as the people in the delta would be less affected by air, land, and drinking water pollution. domestic and international actors involved in the resource sector nigeria‟s rentier nature has made its supervisory agency in the oil and gas sector to be redundant. the nigerian national petroleum company (nnpc) has been more of an observer in the oil and gas exploration as it does not engage in exploration but in monitoring the multinational oil companies, who employ experts to do its work and pay rents to the nigerian government, excluding the local oil companies in the process. with a 57% stake in the joint venture contracts it has with all oil companies operating in nigeria, the nnpc does not seem to care how much is made as long as money keeps coming into the coffers of government. the problem with this kind of arrangement is that in the process it had negatively affected the benefits nigeria should get from the resources. as noted by mahler (2010: 20): because of their economic importance (for example, technical know-how), the multinationals and especially shell have influenced the dynamics of the violent conflicts, mainly through three causal channels: firstly, they obviously carry at least part of the blame for the environmental pollution caused by oil production in the delta. furthermore, they have indirectly contributed to the increased militarization of the conflicts, for example, by demanding that the nigerian state provide official security services, even when the civil protests were still mainly peaceful, as in the mid-1990s. the oil companies also make use of private security services, some of which are extremely brutal. some oil companies have also provided financial assistance to potential militant actors in order to “pacify” them. while this might reduce violence in the short term, the risks of further empowerment of militant groups in the long run are obvious. finally, foreign oil companies provide financial support and different types of “development projects” to their so-called host communities…increased after the ogoni protests, and while it, in the absence of responsible state actors, brings about some short-term mitigation of daily burdens for the local people, it also has conflict triggering impacts. the donations for example generate resentment between the people of the host communities and other (ethnic) communities which do not benefit from such financial support. transnational oil theft network the issue of oil bunkering or theft of oil in the niger delta region has been well documented as it has become one of the major sources of making money in the region. most of the militant activities in the region are linked to this thriving trade. the petroleum resources are sold to neighbouring states like cote d‟ivoire, senegal and benin where they are refined and sold, sometimes even back to nigeria. the enormity of the criminal network is such that it is not only the pipeline saboteurs, but the security outfits and government officials that are involved in the sleaze that has ensured that a lot of people make a lot of money from unauthorized sale of petroleum resources. this is done mainly in the high seas and in the creeks and involves a whole lot of people. “because of the broad 419 afr. j. environ. econ. manage. involvement of influential persons in illegal oil theft, the state approach to solving the niger delta crisis is marked by significant inconsistency and, despite growing militarization, persistent reluctance and a lack of engagement” (mahler, 2010: 21). international demand and customer structure according to mahler (2010: 21), nigeria currently exports the majority of its oil, approximately 50%, to the united states. the united states, in turn, imports approximately 10% of its oil from nigeria, and intends to increase this share (and that accounts for the africom craze). the relationship between the two countries since nigeria‟s transition to democracy in 1999 has been harmonious and has been marked by a very benevolent attitude towards nigeria on the part of the united states. in parallel with the expansion of oil imports from nigeria, the united states has increased its supplying of weapons to the country and has expanded its military presence in the gulf of guinea, for example, via naval patrols. moreover, in december 2005 the two countries announced coordinated actions to counter small arms trafficking, to bolster maritime and coastal security, to promote community development and combat poverty, and to fight money laundering and other financial crimes. primarily because of its own economic interests (oil supply), and also because of strategic considerations with respect to the role of nigeria as a regional power in west africa, the united states is generally interested in reducing the internal instability in the country. nevertheless, the united states‟ efforts to exert its influence on the violent conflict in the niger delta have not been quite successful. this is exactly why africom has become an issue in intellectual discourse in the gulf of guinea region. implications for the nigerian government security policy for the niger delta the link between oil and gas governance and the implications for the nigerian government‟s security policy in the niger delta region cannot be effectively discussed without going along with the thoughts of mahler (2010: 7), which had noted that the rentier nature of the nigerian economy was responsible for the problem. she notes that the rentier state theory is universally valid and attributes the linkage between oil rents and authoritarianism to the following causal mechanisms: firstly, it is presumed that oil rents foster the formation of stabilizing patronage networks, widespread clientelism, and distribution policies, all of which lessen the pressure from the population to democratize and may additionally result in the depoliticization of the society. secondly, the abundance of revenues generated by the oil sector means that national rulers do not need to tax the population. this again may disburden the political elite of demands from the population for political participation and accountability on the part of the elites. the rentier state theory does not focus primarily on violence, but rather on the stability of authoritarian rule. however, she notes that it can be assumed that resource wealth makes it easier for authoritarian rulers to use violence in the form of political repression, for example, because it enables the financing of a massive security apparatus. mahler introduces the issue of the resource curse thesis, which has gained prominence within the theoretical debate on natural resources. noting the already-known fact that resource wealth is linked to poor economic growth and other economic problems such as dutch disease effects and poor performance of the agricultural and manufacturing sectors accompanied by an insufficient degree of diversification and extreme vulnerability towards external shocks; mahler focuses on the link between natural resources and violent conflicts, that is to say, that resource-dependent countries are more likely to experience internal instability and violent conflict than non-resource countries. this is partly contradictory to the rentier-state theory. the causal mechanisms assumed to be responsible for this link, according to mahler (2010:8) include, on the one hand, the fact that natural resources can be the motive for violent conflicts. this means that parts of the population might feel that they are deprived of the financial benefits of the resource revenues – while suffering from the ecological and social impacts of production (motive of grievance) – or that resource wealth can be the target of avaricious rebels who wish to take possession of the resource revenues (motive of greed). on the other hand, resource revenues can serve as a catalyst for violent conflict by financing the rebel groups and other actors involved (opportunity, feasibility) and thus prolonging the conflict. finally, resources, and especially oil, can indirectly increase the likelihood of violent conflict by weakening political institutions and/or by triggering socioeconomic decline, because oil producers tend to have weaker state apparatuses than one would expect given their level of income because the rulers have less need of a socially intrusive and elaborate bureaucratic system to raise revenues. as far as implications for security policy is concerned, the niger delta is a very important case study for africa especially as it provides a clear example of the link between poor resource management and protracted conflicts. according to onigbinde (2008: 18-19), the nigerian case can be used as an example of resource-rich countries in africa and the challenge they face once they start to incur wealth from resource production and trade. countries like ghana have discovered oil thereby making it a nation that needs to be watched to ensure that the nigerian situation is not repeated, especially when it holds promises of a stable democracy that nigeria igbeke 420 presently lacks. the need is great because without ensuring that resources are adequately managed to meet the needs of the resource producing region, the security of these nations are at risk. internal violence and civil wars in any african country have massive implications for sub-regional security. in this regard, a stable nigeria is important in ensuring the peace and security in the sub-region and in africa as a whole. adversely, an unstable nigeria will hinder efforts geared towards maintaining sub-regional stability. this assumption is based on the fact that it is easy for conflicts in one country to spread to another very quickly, turning a national concern into a sub-regional one. the problem of the niger delta can increasingly spread especially as african borders remain weak and porous. the artificial and porous borders between african countries have made for easy transportation of arms across these countries and so through the activities of “states, arm brokers and mercenaries, thousands of weapons have been transferred into the niger delta region and used by state security forces, the security factions of oil companies and insurgent groups” (onuoha, 2008). weapons are also being cast-off into the niger delta from the great lakes conflict. these examples show how serious the problem of porous borders in africa is. it is possible to assume that if and when conflicts occur in other african countries; these same weapons will be delivered across from nigeria to other warring factions in the sub-region. in addition to porous borders, ethnic linkages cut across borders. strong ties between families and ethnic groups across borders also create a new form of regional insecurity as it can accelerate the flow of arms and other illicit acts including mobilization for conflicts. the nigerian case could become a template for many other militant groups fighting for resource control. this could be through exchange of information, human capital and small arms and light weapons. this could increasingly link these groups together as they have similar goals and activities. the absence of strong intelligence between african countries makes it even more difficult to stop criminal activities across borders. ethnic militant groups are now building networks and links that cut across borders and there are reports of links between militant groups in the niger delta and groups in guinea and south africa. nigeria‟s role as a strong contributor to diplomacy and african peacekeeping initiatives could be inhibited by the growing insecurity and conflict in the country with a shift of focus of its military from international stabilization onto domestic security issues. economically, nigeria as the largest and the most populous country in west africa and its role as an oil provider to african nations such as benin, togo and ghana is very critical because insecurity in the country will affect the supply and demand of oil. humphreys (2005: 509-510) noted about oil in chad that “control of oil revenues has been central to chadian politics for more than thirty years; it has made and broken political leaders; has incited violence, and has shaped political agendas. but what is perhaps most striking about chadian oil is that, up to 2003, not a single drop has been pumped.” according to 2006 estimates by the oil and gas journal (2007), nigeria is the seventh largest natural gas reserve holder in the world and the largest in africa. in october 2004, nigeria announced that its natural gas reserves could be as high as 660tcf. the government plans to raise earnings from natural gas exports to 50% of oil revenues by 2010. however, the nigerian national petroleum company (nnpc) estimates that $15 billion in private sector investments is necessary to meet its natural gas development goals by 2010. the vast majority of natural gas found in nigeria is associated, meaning that it occurs in crude oil reserves as free gas. because many of the fields lack the infrastructure to produce the associated natural gas, it is flared. nigeria flares more natural gas than any other country in the world, with 43% of its total annual natural gas production being flared. nnpc estimates that nigerian flared natural gas accounts for approximately 20% of the world total. nigeria is working to end natural gas flaring by 2008. however, shell announced in its 2004 people and environment annual report that it would not be able to meet the 2008 goal of eliminating natural gas flaring (oil and gas journal, 2007). implications of the niger delta conflict for the gulf of guinea region from the above expose, it is abundantly clear that the conflict in the niger delta region has many implications for the gulf of guinea region. these are stated below: globalization of conflict the insurgency in the niger delta has gone beyond nigeria; it has gone regional, and as such, it should no longer be the responsibility of the nigerian government but that of ecowas and the gulf of guinea commission. however, the problem is that generally, individual states do not accept that internal problems could have regional implications. they prefer to call insurgents „bandits‟ and „militants‟, and take it as an internal problem that can be handled domestically even when it is clear that the activities of these „bandits‟ affect the country and spill over into other countries of the sub-region. this challenge of the perception of the conflicts in the various states of the region is hinged on the protection of sovereignty by these states. the quest to protect sovereignty has unfortunately led many states to take on more that they can ordinarily take instead of employing a regional and more global approach to stem the tide of insecurity in the region. 421 afr. j. environ. econ. manage. misuse of advantages the gulf of guinea has many advantages. first, because of its closeness to the major markets in europe and north america; secondly, there are no environmental hazards; and thirdly, the quality of oil produced in the region is far better than in other places. however, the challenges are that there is unskilled workforce in the region. there is no capacity to retain everything about the oil. there is no diversification, even when a lot can be gleaned from the crude deposits in the region. thus, there is exploitation and no expropriation; that is to say, government is incapable of acquiring all it could in order to make adequate use of all the wealth accruing from the oil and gas deposits from the region. the oil from the region goes out cheap and comes back expensive, and it is still the poor masses that suffer most in the event of high prices for oil and gas resources. people in the region become desperate as the gap between them and those who take out of the region becomes wider each day. moreover, the rentier nature of government in resourcerich nations like those in the gulf of guinea (nigeria specifically), where government after collecting high rents from multinationals, become accomplices in the bid to ensure calm and acquiescence from the people of the region, leads to militant struggles, and in the process, a lot of advantages and development are lost. moreover, as noted by onyeukwu (2007: 21) “the presence of oil revenue of course ensured that the military dictatorships in nigeria did not need to tax the majority of the people, which is a way was useful to them, as taxation through which to fund government could have led to unrest, which may have forced them out of government”. he further categorized the nature of conflicts in the nd into 5 major areas – intra-community; inter-community, inter-ethnic, community-oil company, and states-federal government (onyeukwu, 2007: 23). maritime security all the states in the gulf of guinea region are weak in the waterways security. the world super powers control the maritime security of the gulf of guinea region, and this is an indictment on the governments of the region. this weakness in the control of the waters gives room for penetration of the borders by external actors to even compound the conflicts in the region through thriving arms trade and preponderance of mercenary activities. border security as with the waterways, so it is with the borders. presently, there is porosity in the borders connecting the gulf of guinea states. moreover, there is a report that the niger delta militants have started tracing their steps towards ghana ostensibly to train them in the art of militancy as the country is grappling with how best to govern their new-found oil and gas resources. this does not bode well for the region as it could trigger conflict between the two countries with devastating effects. ecowas weaknesses ecowas has identified the niger delta among the hot spots of the region, the commission as an institution is being careful not to intervene directly in nigeria as it is its major financier. this is not helpful as the commission had intervened directly in togo, cote d‟ivoire, liberia and other states in the sub-region. but then nigeria is a superpower in the region and needs to be handled carefully. this is another major implication for the conflict in the region. governance there has not been any serious form of governance in nigeria. the thirty years of military misadventure in the country swept away any form of governance that the country was ever going to get; thus, it is difficult to talk about governance of oil and gas in nigeria. talk about governance can only be discussed in relation to angola which has made strident effort to control its oil and gas resources, and it is the bedrock of the government there now. there is coherence in the leadership in angola in terms of oil and gas unlike what obtains in nigeria. thus, three factors were responsible for the problem in the nigerian state: i. three decades of military rule that could not produce public good; ii. corruption that did not allow for any form of governance in the sector; iii. role of organized crime brought about the issue of arms in the region. these three factors exist within the context of the niger delta which had led to militancy, and which was a result of political consciousness that erupted after decades of agitation for inclusion in the affairs of resource governance. conclusion this study centred on the importance of comprehending the synergy between the governance of resources and the conflict that has bedeviled the niger delta region of nigeria and the gulf of guinea states in general, and found the governance of resources by states in the gulf of guinea culpable for the imbroglio, a culpability that centres on government‟s laisser-faire attitude to the manner the resources from the region are expended to the generality of the populace. the inability of governance in nigeria is shown in the igbeke 422 fact that government does not know how much oil and gas wealth is produced; there are no metres at the point of production to gauge how much oil is produced; and at the point of export, government depends on the oil companies to tell her how much is being exported. this is simply a very clear case of a government that is not serious about monitoring the activities in the area. despite the fact that successive audits embarked upon by the nigerian government have consistently shown these anomalies, government is yet to react as there are still no metres at the production points. recently, the nigeria extractive industry transparency initiative (neiti) described the records of the country‟s crude production and export as unclear, saying that after 58 years of oil production, the country does not know exactly the quantity it produces. the oil and gas sector is shrouded in secrecy. the audit reconciliation carried out by neiti in respect of its first and second audit report could only narrow down the discrepancies in revenue reporting to $16 million (1999 2004) and $155 million for 2005 (this day, 29/03/2010). this does not bode good for a country that claims to have the interest of its people at heart. and of course, when people are consistently denied what is due them, there is bound to be crisis. the insecurity and conflict in the gulf of guinea region has been there for over forty years and it is a well-known fact that arms follow money; because there is a lot of resource wealth in the gulf of guinea, and there are scattered cases of skirmishes all over the neighbouring regions, there is bound to be arms in the region. these are used in the fight for control of bunkered oil that occasions conflicts constantly. of course, given the role of political godfathers in the region that have been arming the youth for electoral purposes, the problem has been exacerbated by inconsistencies in the political leadership of the region. thus, it is only through a concerted effort on the part of the political leadership to gain tighter control of the resources and 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political disorder in the niger delta. niger delta economies of violence working paper, 16. www.geography.berkeley.edu/projectsresources/.../nigerdelta/wp/1 6-watts.pdf) 1 in ternationa l scholars journa ls african journal of environmental economics and management issn 2375-0707 vol. 5 (3), pp. 302-315, march, 2017. available online at www.internationalscholarsjournals.org © international scholars journals author(s) retain the copyright of this article. full length research paper are investments in energy efficiency and renewable energy technologies complementary? an econometric analysis of households’ environmental investments george abuchi agwu federal university, ndufu-alike ikwo, nigeria. e-mail: george78ng@yahoo.com. accepted 14 november, 2016 economic incentives have received much attention in the literature of the two dimensions of environmental friendly energy consumption: energy efficiency and renewable energy investments. this study shows that the incentives, if not well targeted may be irrelevant because household investors in the different dimensions possess different characteristics that policies could target. the findings indicate that investments in renewable energy technologies decrease with age of household investors and not affected by household income constraint while investments in energy efficiency are not affected by age of household investors but by income constraint. correlation coefficients among all the investment equations in the multivariate model are strongly positive suggesting complementary investment choices across dimensions. keywords: energy efficiency, renewable energy, multivariate probit, ordered probit. introduction as scarcity of natural resources and environmental degradation get more national and international attention, calls for sustainable energy consumption get intensified. most governments in the developed world employ incentives or information campaigns to promote energy savings and other eco-friendly behaviours. with respect to purchase of eco-friendly appliances, many empirical studies have assessed how measures such as eco labelling, tax incentives, and subsidization policies impact on the governments objectives. however, most of these studies employ univariate methodologies that assume independent decisions with respect to the various dimensions of pro-environmental behaviours. although industry and agriculture represent the bulk of energy demand, there exists substantial potential to reduce total energy demand in the residential sector. as mentioned above, a lot of policy efforts are presently concentrated at demand side management (dsm) policies, i.e., price and non-price policies designed to promote energy conservation in the residential sector. this opens up a number of choice for household energy consumption: in order to reduce the quantity of energy for a given energy service, a household can decide to invest in energy efficient technology that induces energy saving or decide to reduce energy waste by engaging in prudential energy use such as switching off standby model of appliances when not in use (jansson et al., 2009). by reducing its consumption of energy, the household contributes to reducing future greenhouse gas (ghg) emissions. reducing greenhouse gas emission can also be achieved by investing in renewable energy technologies such as wind turbine, ground source heat pump or solar panel. the use of renewable energy technologies differs from the other forms of sustainable energy consumption because for a given level of renewable energy consumption, less greenhouse gases are emitted. the relationship among these choices of responsible energy use is an important policy consideration. for instance, energy efficiency technology investments and 2 agwu 303 prudential energy use maybe driven by money savings, environmental consciousness or both. on the other hand, investment in renewable energy technology are most likely driven by environmental consciousness and other non-monetary concerns. if households are simultaneously environmentally conscious and income constrained, they could leverage on the synergy between these dimensions of pro-environmental choices as identified by dato (2015) to satisfy their objectives. however, certain combinations of energy efficiency and renewable energy technologies may be more appealing to the households than others. for instance, households may favour energy efficiency-wind turbine combination or energy efficiencysolar panel combination due to for example existing policies or space requirement. thus, the lumping together in two groups of all energy efficiency and renewable energy investments do not provide a clear path for policy mediation. furthermore, prudential energy use is more of an attitude than a decision: such that its role is to predict energy efficiency, renewable energy investments or both rather than being an alternative choice as dato (2015) suggests. literature review empirical determinants of pro-environmental decisions the traditional economic theory examines household’s behaviour on the basis of consumption as broadly defined in terms of households 'purchases and other decisions such as labour supply. the idea is that households’ decisions are described by utility function subject to budget constraint and other household’s characteristics which generates testable restrictions on household’s behaviour. the household characteristics include disposable household income, age, gender, education, occupation, marital status, family size and number of children. empirical studies of energy efficiency and renewable energy technologies adoption suggest that these characteristics are important decision variables: household size is hypothesized to predict adoption because budget constraints increase in household size given limited number of income earners within the household. on the other hand, large household increases the incidence and size of economics of scale of energy savings incident upon adoption of the appliance. so on the one hand, households size may tighten the constraint faced by households with respect to clean energy adoption. on the other hand, household’s size increases, the private benefits derivable through clean energy adoption. this is thus one critical testable hypothesis. millock and nauges (2010) found a positive and significant relationship between the household size and the adoption of water saving technologies. socio-economic characteristics household’s income represents largely the budget to be maximized and thus all things being equal, adoption of clean energy is expected to rise with income. however, on the basis of economic theory, the role played by income in driving households’ decisions is difficult to assess. on the one hand wealthier households should have greater financial ability to invest in energy-saving appliances. on the other hand, wealthier households could have less elastic demand for consumption in general compared to poorer households. not surprising therefore, empirical studies have found varied results regarding household income. whereas, berk et al. (1993) shows that income has positive effect on water conservation, de oliver (1999) shows that lower income households are more conservative of water than higher income households. sütterlin et al. (2011) found that lower-income households were more likely to adopt energy saving habits. martínez-espiñeira and garcíavaliñas (2013) also found negative relationship between income levels and the adoption of water conservation behaviour. a higher education level is expected to be positively correlated with knowledge and awareness about issues relating to the environment. thus, it is expected apriori that more educated households/respondents are more likely to undertake pro-environmental actions given their knowledge. the analysis of the oecd survey undertaken in eleven countries showed that the level of educational attainment increased pro environmental behaviours in all the five areas (transportation, water, energy, waste, and food) covered (oecd, 2011). this was confirmed empirically by martínez-espiñeira and garcía-valiñas (2013). the roles played by marital status, age and occupation varies substantially depending on the dataset and technologies being studied (see ameli and brandt, 2015) social and relational factors the social system or norms just like the cost benefit analyses in the case of energy efficiency investment may affect the adoption of environmentally friendly behaviours. in addition to environmental concern, zhai and williams (2012) investigates the influence of social acceptance and shows in a specific case of photovoltaic (pv) adoption that social acceptance also affects the adoption of renewable energy. in a model grounded in diffusion of innovation and social capital theories, mcmichael and ship worth (2013) underscore social system as important factor in the diffusion of environmentally friendly energy technologies. in particular, mcmichael and shipworth (2013) emphasized that word-of-mouth and experience of innovators is far more potent than standard campaigns and advocacy in the diffusion of clean energy innovations among british communities. those community members who are seen as opinion leaders might influence other members of the community 3 304 afr. j. environ. econ. manage. towards a particular orientation with respect to the desirability of environmentally friendly energy technologies. mills and schleich (2012) explored how opinion leadership contributes to the innovativeness of adopters and found that those classified as opinion leaders are more likely to be among the first 5% of adopters of given innovation. nair et al. (2010) show that adoption is associated with income, education and age but suggest that opinion leaders influence non-adopters through personal communication channels that maybe fostered by policy. moral hazard and spillovers many other factors not classified above have been shown to matter for household’s consideration of adopting environmentally friendly energy technology. these factors may be related to tenure in primary accommodation, incentives structure and spillover effects. for instance, at what point during the households’ residency in the primary accommodation is it optimal to install energy efficiency or environmentally friendly energy technology? most empirical studies find evidence of positive tenure effect (davis, 2010;murray and mills, 2011; martínez-espiñeira and garcía-valiñas 2013). however, tovar (2012) found negative effect of tenure on household’s adoption of energy efficiency ecoinnovation in the uk. the most common justification for positive tenure effect is that as households develop attachment to their current residence, they become more likely to install measures to make it compliant to sustainable consumption of energy. however, the question of when to install these measures depends also on the particular type of measure under consideration. while it might be optimal to install measures that have to do with the built environment such as cavity walls insulation at the beginning of residency when other renovations or constructions are going on, for others such as light bulbs anytime may be just fine for adoption. given that tovar, (2012) model was based on cavity walls insulation, loft insulation and boiler upgrade, this result is not at all surprising. split incentives between landlords who install energy using equipment in rental accommodations and renters who pay the energy bills has been extensively studied as factors that may get in the way of households’ energy efficiency behaviour. landlords may buy cheap inefficient appliances when it is the responsibility of the tenants to pay the energy bills. davis (2010) empirically compared appliances ownership patterns between homeowners and renters and found that renters are less likely to have efficient appliances compared to homeowners. this is because of the lemon problem which arises from the fact that potential tenants cannot observe appropriately the quality of energy using equipment installed by the landlords (akerlof, 1970). as a result of this, the landlords cannot possibly signal the quality of the equipment in their homes through higher rental fees (gilligham et al., 2012) on spillover effects, nair et al. (2010) show that as households become aware of the benefits of adopting energy efficiency technologies through past investments, they become more likely to devote further outlay to energy efficiency. this thus implies that information acquisition, education or learning by doing is related to the unobservable driving the probability of households investing in more than one of the energy efficiency measures. similarly, brown (2014) show that adoption of energy conservation habits has positive spillover effects on related habits such as recycling and water conservation and is mediated by positive attitudes to the environment. a model of clean energy adoption should therefore be multi-disciplinary in nature including economic as well as other considerations that are not purely economic and consider possible relatedness among the different dimensions of environmental behaviour. such models would estimate environmental behaviour more efficiently and identify policy relevant covariates. the interaction between energy efficiency and renewable energy investments a number of empirical studies has been conducted on how households’ behaviours affect adoption and investment in energy efficiency. this is because substantial opportunities exist within the residential sector to reduce energy consumption and mitigate climate change (fouquet, 2010; dietz et al., 2009; and vandenbergh et al., 2008). there is a large evidence that economic factors are motivations for energy efficiency (kempton and neiman, 1986; and steg, 2008) and can be helpful in designing appropriate taxes or subsidies mechanism to promote energy saving actions. for instance, energy efficient behaviour maybe brought about by the need to save household expenses or to reduce energy bills. achieving this objective however is not so simple; the potential gain from reducing energy use can be hindered by some problems such as split incentives, uncertainty about the gain of energy efficiency, moral hazard problem that may prevent households from adopting or investing in an energy conservation system. reducing energy use can also lead to reverse effects such as rebound effect or take-back effect (chitnis et al., 2014; urban and scasny, 2012). problems such as rebound effects operate through household’s motivations. if households are motivated by economic concerns such as savings in energy expenditure, they are more likely to be subject to rebound effects than those motivated by environmental concerns. studies such as urban and scasny (2012) suggest that the rebound effect can be solved by environmental campaigns geared at cultivating pro-environmental motivation. there is however, no empirical consensus on the impact of environmental concern on energy-saving behaviour. earlier literature 4 found that environmental concern does not have any effect on both energy consumption and energysaving actions (gilligham et al.,2012). others, mostly recent studies tend to find significant effects of environmental concerns on energy-saving actions (capstick et al., 2015; barr et al., 2005; and whitmarsh and o’neill,2010). while energy efficiency investments correlates with the desire for money savings, empirical studies show that investment in renewable energy is driven by environmental attitudes. this follows from the theory of reasoned action which characterizes peoples’ actions as arising from their cognitive assessment of possible outcomes based on held attitudes. most empirical studies relying on consumers’ stated preference tend to find strong roles for environmental attitudes in consumers’ willingness to adopt clean energy technologies (ek and söderholm, 2008; zoric and hrovatin, 2012; liu et al., 2013.). although such hypothetical studies may deviate from observed behaviour, it clearly distinguishes renewable energy investment choice from energy efficiency investment (cameron et el, 2002; kotchen and moore, 2007). thus on apriori, those households with greater environmental consciousness are expected to engage more with renewable energy technologies than others. if they are equally conscious of money savings, then they are more likely to invest jointly in renewable and energy efficiency technologies. different dimensions of pro-environmental behavior may be distinguished (lynn,2014). both economic and environmental motivations have different effects when dimensions of environmental friendliness are distinguished. as far as energy consumption is concerned, energy efficiency can be distinguished from the use of renewable energy. the use of renewable energy has been compared to private provision of public goods and driven by altruistic motivation (welsch and kuhling, 2010). energy efficiency on the other hand mainly derives from economic motivation in form of reducing expenditure (diaz-rainy and ashton, 2015). energy efficiency behaviour can be further sub-divided into energy efficiency investment and curtailments (jansson et al., 2009). the former involves the acquisition of new technologies, low-energy appliances (top-rated energy-efficient appliances, low-energy lightbulbs, energy-efficient windows, etc.) that needs monetary investment. the latter refers to non-monetary investments that are behaviour changes such as turning off lights, cutting down on heating or on airconditioning and switching off standby mode of appliances. monetary energy efficiency investments are less affected by proenvironmental motivations than non-monetary behaviour changes (guagnano et al., 1995). both economic and environmental concerns may have significant effects on energy-saving actions which are the outcome of both monetary and nonmonetary investments. urban and scasny (2012) investigates in a multi-country setting how environmental concern affects the adoption of monetary versus non-monetary investments in energy efficiency. they find a positive and significant effect of proenvironmental motivation in both cases. notwithstanding the distinguishing features of energy efficiency behaviour and the use of renewable energy, relevant synergies may exist between them. the different variables that affect the renewable energy adoption decision of household may have significant effects on energy efficiency investments as well. the fact that studies mostly focus on either renewable energy adoption or energy efficiency investment may explain empirical disparities in the effect of economic and environmental concerns. if the two decisions are interrelated, it cannot be estimated independently. in this case, univariate models that estimate separately the two decisions of renewable adoption and energy efficiency are potentially inefficient because there may exist unobserved characteristics that motivate joint occurrence of the two decisions. for instance, household that is proenvironmental in their held attitude can find it necessary to additionally invest in renewable energy having already invested in energy efficiency. in this case, the household may rely on its environmental conscientiousness to combine the two investments. similarly, households having invested in energy efficiency may have limited financial capacity to additionally invest in renewable energy. therefore, by jointly analyzing the two possible decisions of the adoption of renewable energy and investment in energy efficiency that are taken by the household, one can capture the interrelation and the interaction between them. such investigation has potential gain for policy designs as adoption of renewable energy and investments in energy efficiency are both important in the transition to green economy. data and variables description the data for this study comes from 2011 oecd crosssectional survey which collects data from a sample of more than 12 000 respondents, approximately 1000 households for each country: australia (shorthand: aus), canada (shorthand: can), chile (shorthand: chl), france (shorthand: fra), israel (shorthand: isr), japan (shorthand: jpn), korea (shorthand: kor), the netherlands (shorthand:nld), spain (shorthand:esp), sweden (shorthand:swe) and switzerland (shorthand:che). the sample was stratified to achieve representativeness. in each country stratification was done according to different parameters: age, gender, region and socio-economic groups. the target respondents were between 18 and 70 years of age and those who had influence on household purchasing decision and expenditures. gender was approximately half male and female for all countries. region was stratified and quotas created using three to five regions. for income stratification, households’ after agwu 305 5 306 afr. j. environ. econ. manage. table 1. summary statistics for the dependent variables. country appl bulb windows thrm heat solar pump wind mean australia 0.690 0.910 0.130 0.580 0.150 0.200 0.030 0.034 canada 0.670 0.870 0.510 0.380 0.650 0.040 0.040 0.029 chile 0.410 0.950 0.140 0.310 0.060 0.020 0.010 0.013 france 0.740 0.860 0.590 0.450 0.440 0.070 0.050 0.015 israel 0.590 0.840 0.130 0.200 0.110 0.670 0.030 0.020 japan 0.480 0.480 0.200 0.200 0.070 0.050 0.010 0.001 korea 0.690 0.630 0.490 0.380 0.590 0.070 0.030 0.027 netherlands 0.610 0.890 0.730 0.490 0.480 0.040 0.020 0.011 spain 0.740 0.910 0.540 0.210 0.470 0.060 0.020 0.016 sweden 0.620 0.870 0.390 0.290 0.340 0.040 0.160 0.019 switzerland 0.620 0.800 0.490 0.370 0.430 0.050 0.070 0.008 total 0.620 0.820 0.380 0.340 0.330 0.110 0.040 0.017 tax income quintiles were estimated for each country, then responses from the survey income question were used to fill the quotas. when quotas were filled, respondents with these characteristics were stopped from completing the questionnaire. more details on the questionnaire design, respondent targeting and quota sampling are provided in (ameli and brandt, 2015; oecd, 2011). the study uses as dependent variables different forms of households’ self – reported environmentally friendly technology adoption collected as part of oecd, 2011: households were asked whether they undertake the following activities between 2001 and 2011: bought appliances that received a top rating in terms of energy efficiency (appl) bought low energy light bulbs (bulb). installed energy efficient windows i.e double or triple glazing (windows). engaged in thermal insulation of walls or roof (thrm) installed heat thermostat (heat) installed solar panels for electricity or hot water (solar) installed ground source heat pump (pump) installed wind turbine for electricity (wind) the variables; appl, bulb, windows, thrm, heat, solar, pump and wind representing the various types of environmentally friendly energy investments and considered as binary outcomes are the dependent variables of the equations defining multivariate probit models. table 1 summarizes the dependent variables by countries surveyed. the following sub-sections describe the main independent variables used in the study. socio-economic characteristics available socio-economic variables in the household dataset include the respondent’s age (age), gender (male), size of household (hhsize), the number of years of education after high school (education), annual net household income (income) and employment status of households’ head created as dummy variable (professional). there is a dummy variable that takes a value of 1 for households stating that they cannot cope with their current income (nocope). studies suggest that individuals with higher income and education tend to be more likely to adopt energy efficient technologies, while the influence of age and gender is less clear (ameli and brandt, 2015). income might be a relevant variable considering that investment cost seems to be one of the major barriers to investing in energy efficiency. however, income would only be expected to influence investment decisions if lower-income households are creditconstrained or if their ability to assess the profitability of investments is less well developed than for higher income households. otherwise, lowerincome households would be able to identify profitable investments like higherincome households and they would be able to obtain a credit to invest. at the same time, a variable that captures the respondent’s education should capture any difference in the ability to assess the profitability of investments across households better than an income variable. thus, if income and/or education is significant predictor of adoption, it shows evidence of irrational consumer decision and is one of the tested hypotheses of the current study. approximately, the average annual household net income in the dataset is 37 868 usd with considerable differences in means across countries. chilean households declared the lowest average annual income (13 585 usd), while the highest was declared by households living in switzerland (62 278 usd). 36% of household’s experience difficulty in coping with their salary and as expected, there are more than average number of households expressing this difficulty in chile (43.6%), france (43.8%) and israel (42.8%). chile and israel are the two main countries with a highest percentage of professionals as household heads, 36% and 31.8% respectively, while france is (11.5%). a number of respondents in the sample has at least university education as the average length of education 6 agwu 307 after high school is 3.5years. dwelling characteristics questions about characteristics of dwellings were asked, such as home-ownership versus rental (owner), dwelling type (detached house), number of years lived in the primary residence (tenure) and whether households live in a rural or urban area (rural). controlling for home ownership provides evidence on the frequently cited owner-effect. in most countries, investment incentives for owners who rent out their apartments are weak, since in general it would be the tenant who benefits from any energy savings. at the same time, tenants may not be allowed to invest, but even if they are, their incentives to do so are probably weaker than those of owners who live in their home, as tenants are more likely to move before their investment pays off. many empirical studies have confirmed the presence of an owner-effect (tovar, 2012; davies, 2010). the number of years already spent by households in their house may also matter. some investments may be more likely to be made as a household moves in to a dwelling, since this is usually a good moment for home improvements. in other cases, the length of time that households have already spent in their home may be indicative of their attachment to it and hence a longer tenure may increase the likelihood to invest. the floor size (floor_size) of household’s home, whether households live in a rural area and/or have a detached house may be indicators of space availability (michelsen and madlener 2012), as living in larger homes may be relevant for investing in energy technologies requiring more space. a good number of respondents (63%) in the dataset own their residence and more than half of the investigated households live in a detached house (53%). highest rates of ownership are observed in spain (79.8%), korea (69.8%) and the netherlands (68%), while relatively many households live in a detached house in australia (82.6%), chile (77%) and the netherlands (74%). on average, households have lived for approximately 13 years in their primary residence, although average tenure is longer in japan (18 years). attitudes and behaviour towards the environment to reflect the role of social context, households’ beliefs, attitudes and behaviours regarding the environment, some dummy variables were created. these include a dummy variable for households that participate in a nongovernmental organisation (ngo) and another one for those that are specifically in an environmental ngo (env ngo). there is a dummy variable for people who rated the environment as the most pressing concern (envtopcon) and another one for those who instead rated the economy as the most pressing concern (ecotopcon) respondents were asked questions regarding their willingness to make sacrifices to protect the environment, their assessment of the need to do so and the role of technology in solving environmental problems. depending on their answers to those questions households were grouped in three clusters i) those who are the environmentally motivated and are willing to make sacrifices in their lifestyle to solve environmental problems (altruists), ii) those who are not willing to make much effort to solve environmental problems because they believe that the climate problems are often exaggerated (sceptics), and iii) the third group believe in the reality of climate problem but that technological innovations are key to solving them (green growthers) (see oecd, 2011)45% of the respondents are classified as altruists (altruists) with variations across countries, 65% of respondents are classified as “altruists” in israel and around 55% in france and sweden. on the other hand, on average across countries 35% of respondents are sceptical (skeptics) about the existence of environmental problems. japan showed the highest level of scepticism (45%), while chile showed the lowest level (18.8%). in most countries, membership in non-governmental organisation is quite popular; more than 50% of respondents are engaged in some non-governmental organisation (ngo). only in japan is this share much lower, just above 30%. on average across countries around 10% of respondents are engaged in an environmental ngo (env_ngo). to investigate cost bias hypothesis, a dummy is constructed in line with ameli and brandt, (2015) to capture whether households give higher weight to investment costs than to future energy savings. in principle, individuals should be indifferent between lower investment costs and higher energy prices, since these factors have an equivalent impact on the net present value of energy saving investments, the sum of forecasted discounted energy savings minus the upfront investment cost. when the rating given to initial investment cost exceeds the rating for future energy prices by three points on the scale, respondents are considered as having a bias towards initial investment costs and the dummy variable takes a value of 1. households perception of quantity and costs of energy use to measure this perception, questions regarding households’ knowledge about their energy consumption/spending and method of payment of energy bills were used to create dummy variables. during the survey, respondents were asked to get hold of their energy bills before answering the survey, but only about 55% were able to provide information about their energy spending. (ebill_known) captures if household was able to provide this information or not) on average across 7 308 afr. j. environ. econ. manage. table 2. summary statistics for the independent variables. variable obs mean st. deviation min max socio-economic characteristics income ($) 8, 765 37868.04 24681.14 2304.525 159160.6 education (years after high school) 8, 765 3.500492 3.152784 0 12 age (years) 8, 765 42.01352 13.7693 18 69 household size 8, 765 3 1.416855 1 6 married 8, 765 0.6361252 0 1 male 8, 765 0.4913949 0 1 nocope 8, 765 0.3619079 0 1 cost bias 8, 765 0.3631372 0 1 share of non-graduate 8, 765 0.0960471 0.2182375 0 1 share of graduate 8, 765 0.2209009 0.2778962 0 1 share of under 18 8, 765 .1538248 0.2155072 0 0.8333333 share of over_55 8, 765 0.1203204 0.2503451 0 1 beliefs, attitudes and behaviour behaviour index 8, 765 7.427157 1.864599 0 10 ecotopcon |materialism 8, 765 0.352811 0 1 envtopcon 8, 765 0.1589084 0 1 ngo 8, 765 0.517784 0 1 env ngo 8, 765 0.1070316 0 1 skeptics 8, 765 0.3531388 0 1 dwelling characteristics floor size (square miles) 8, 765 109.8426 59.85085 32.13473 334.1077 detached house 8, 765 0.5360597 0 1 owner 8, 765 0.6306343 0 1 tenure 8, 765 12.85756 13.67766 1 40 rural 8, 765 0.3445337 0 1 perception energy use knowledge electric bill known 8, 765 0.5518767 0 1 quantity of electricity known 8, 765 0.1902967 0 1 pay as you use 8, 765 0.9116538 0 1 note: standard deviations are not calculated for dummy variables countries while (kwatt_known) captures if households were able to provide energy use information by volume. regarding prudence in energy use (curtailment), the “behaviour index” variable captures whether respondents perform certain energy conservation actions regularly, such as turning off the lights when leaving the room, cutting down on heating/airconditioning to limit energy consumption, running full loads when using the washing machines, washing clothes using cold rather than warm/hot water, switching off the standby mode of appliances and air dry laundry rather than using a clothes dryer. the behaviour index ranges from 0 to 10, where higher values indicate that households perform several of the sections regularly. the data suggest that households perform quite regularly energy conservation actions, as on average across countries the behaviour index takes values around 7. lower values of the index are observed in sweden (5.55) and switzerland (6.82), while higher values are observed in chile (8.32) and spain (8.39). table 2 summaries the dependent variables: empirical methodology and results a model of joint investment: energy efficiency and renewable energy technologies in principle, households could invest jointly in energy efficiency and renewable energy technologies. empirical modelling of such joint investment follows from ekholm et al. (2010) and dato (2014) which describes the consumer energy investment problem as utility maximization under budget constraint. assuming that utility derived from energy consumption is separable from utility due to other forms of consumptions, households may set aside energy 8 agwu 309 budget specific for solving households’ energy consumption problems. the energy budget holds the income that a household devotes to energy service demand and any grants or other forms of financial support the household may receive for energy procurement. it could be assumed that the households would prefer to invest in energy efficiency in order to minimize energy expenditure and in renewable energy to satisfy private affection for the environment. the affection for the environment unlike materialistic consumption is intrinsically motivated and may receive less than optimum budgetary allocation from the household’s budget (welsh and kuhling, 2010). the energy budget constraint expresses the limited investment capacity of the household. aside energy, other realms of consumption compete for households’ income. furthermore, for households that have environmental affection, energy efficiency investments compete with renewable energy investment for the households’ energy budget. therefore, there may be substitutability rather than complementarity between energy efficiency and renewable investments. however, apart from private utility from income and/or other forms of consumption, households may also derive private affective utility by virtue of proenvironmental energy consumption. in this case, investment in renewable energy complements energy efficiency investment. two opposing forces therefore, drive households’ investments in environmentally friendly energy technologies. that is, the forces of income or other forms of consumption and the forces of environmental affection. thus, under multi variant estimation framework, the sign of the correlation coefficients suggests the nature of relationship existing between the choice dimensions. econometric estimation to study household choices of the six pro-environmental investments, a corresponding number of binary equations were generated. every type of pro-environmental investment corresponds to binary choice equation and households’ choices are modeled using correlations among the equations’ disturbances. if the correlation coefficients are significantly different from zero, then meaningful relationships are established among the various choices. a significant positive relationship suggests complementary choices while significant negative relationship suggests substitute choices. since, mvp model is used in this case, the sign of the correlation coefficients depends on the data rather than specified apriori. the multivariate model specifies households’ choices of the different types of clean energy investments on some function of covariates, allowing for simultaneity of investment choices. as households could adopt more than one type of energy investment simultaneously, another advantage of this model is that patterns of household’s investments in as many investment types as possible is estimated empirically on the basis of the data. no restriction in this pattern is needed under the multivariate model. relations among the different choices of households’ investments are modelled through correlation parameters that are assumed arbitrary and have to be estimated (calia and farrante, 2013). these correlations tell us how different types of clean energy investments are combined by households and if there are unobserved factors, besides those explicitly considered, that simultaneously affect different choices of investment. this reflects the traditional household’s utility maximization over a basket of goods under a budget constraint. the mvp is adopted similar to calia and farrante (2013), specifying a joint multivariate normal distribution for the error terms. formally consideringmclean energy investments for each observation, there are m equations each describing a latent dependent variable to which there is a corresponding observed binary outcome. the model is written with suppressed subscripts as follows; 𝛾𝑚 ∗ = 𝛽𝑚 ′ 𝑋𝑚 + ℰ𝑚𝑚 = 1, . . . , 𝑀 𝛾𝑚 = 1 𝑖𝑓𝛾𝑚 ∗ > 0 𝑎𝑛𝑑 0 𝑜𝑡ℎ𝑒𝑟𝑤𝑖𝑠𝑒 𝐸𝑞𝑢𝑎𝑡𝑖𝑜𝑛 1 where xm is a vector of p covariates for the m-the equation (m = 1, …, m ), β’ m is the corresponding vector of parameters and εm is a vector of error terms corresponding to each equation of the model assumed to be jointly normally distributed with means of 0 and variance of 1 and correlation coefficients; 𝜌. the multivariate probit model considers six potentially related binary outcomes. the relatedness exists beyond conditioning on regressors and occurs through correlation of the errors that appear in the index-function model formulation of the binary outcomes. in general, the multivariate probit models consider two or more equations of binary outcomes and is the multinomial analogue of seemingly unrelated regression model with the dependent variables in form of binary outcomes. the observed outcomes are: 𝑌𝑖 = 1 𝑖𝑓𝑌𝑖 ∗ > 0 0 𝑖𝑓𝑌𝑖 ∗ ≤ 0 𝑖 = 1, 2, 3 …𝑀𝑬𝒒𝒖𝒂𝒕𝒊𝒐𝒏𝟐 the model collapses to univariate probit models for the separate dependent variables if 𝜀s are identically and independently distributed or if 𝜌equals zero. the model may be estimated by means of simulated maximum likelihood (sml) using the geweke-hajivassiliou-keane (ghk) simulator that results in unbiased estimates of the multivariate normal probabilities (see cappellari and jenkins2003). estimationresults two sets of estimations were conducted: in the first 9 310 afr. j. environ. econ. manage. table 3. ranking pro-environmental investments. description investment rank household invests in neither energy efficiency nor renewable energy 0 household invests in only one of either energy efficiency or renewable energy 1 household invests in more than one of energy efficiency and at most one renewable 2 household invests in more than one renewable energy technology only 3 household obtains a mixture of both dimensions involving more than one renewable 4 table 4.technology specific estimates: energy efficiency. windows appl thrm log_income -0.0093* 0.0081 0.0056 education 0.0010 -0.0071 0.0026 male 0.0318 0.0359 0.0200 married 0.1170** 0.2149*** 0.1260*** nocope -0.0881** -0.0222 -0.0860** age 0.0045** -0.0027 -0.0004 hhsize 0.0215 0.0010 0.0229 share age55 0.1059 0.1067 0.3289*** behaviour_index 0.0554*** 0.0789*** 0.0789*** ngo 0.1247*** 0.1945*** 0.1382*** env_ngo 0.0201 0.0851 0.0775 ecotopcon -0.0224 0.0222 -0.0335 envtopcon 0.0263 0.0206 0.0196 skeptics -0.0551 -0.0485 0.1028*** log_floor 0.2238*** 0.1695*** 0.2891*** owner 0.4042*** 0.2293*** 0.3903*** dhouse 0.0250 0.0630 0.2616*** tenure -0.0029* 0.0021 -0.0060*** rural 0.0564 0.0117 0.1507*** pay as you use 0.1402* 0.1532** 0.0652 ebill_known 0.0426 0.0640 0.0181 kwatt_known 0.0034 0.1656*** 0.0276 sample size 8,765 8,765 8,765 waldchi2 (22) = 3,832.48 [six equationmodel] *p <0.05; **p <0.01; ***p <0.001. estimation, determinants of specific choices were estimated using mvp model (tables 4 and 5). along with this, cross correlation coefficients among the various equations were measured (table 6). the objective of the second estimation is to identify the determinants of joint investments in the two dimensions of proenvironmental investments: energy efficiency and renewable energy technologies. investments were ranked according to how they theoretically affect the environment as shown in table 3; ordered probit estimation procedure was used to identify correlates of being in the topmost category. technology specificresults tables 4 and 5 report the results. from table 4, determinants of investments in energy efficiency dimension are marital status (married), income constraint (nocope), energy use prudence (behavior index), social engagement (ngo), space availability (floorsize), occupancy status (onwer), length of stay in residence (tenure) and metering method (pay as you use). in effect, the results confirm popular theoretical predictions: income constrained households are less likely to invest in sustainable energy use and households who are prudent in their energy use tend to seek more opportunities to enhance their energy conservation. there is the lemon problem since those who live in owned houses are more likely than renters to invest in energy efficiency. there is also space factor since investment in energy efficiency increases in floor size of the living home. variation in 10 agwu 311 table 5.technology specific estimates: renewable energy. pump wind solar log_income 0.0042 0.0012 0.0026 education 0.0228 0.0144 0.0214* male -0.0200 0.0709 0.1899 married 0.0618 0.0679 -0.0456 nocope 0.0248 0.0386 -0.0799 age -0.0113*** -0.0136*** -0.0076** hhsize 0.0516 0.0435 0.0732*** share age55 0.3710 0.6198** 0.3703** behaviour_index 0.0342* 0.0442* 0.0614*** ngo 0.1241* 0.1094 0.2144*** env_ngo 0.1911** 0.3867*** 0.2999*** ecotopcon -0.0842 -0.0027 -0.0224 envtopcon -0.0993 0.1147 -0.0382 skeptics 0.2869** 0.2191** -0.0029 log_floor 0.1755** 0.1519* 0.1491*** owner 0.2088** 0.1253 0.3050*** dhouse 0.0616 -0.1325 0.1645** tenure -0.0001 0.0031 -0.0014 rural 0.0325 -0.2518* -0.1033* pay_as_you_use -0.2442** -0.1359 0.0342 ebill_known -0.0354 -0.1742* -0.0452 kwatt_known -0.0292 0.0547 0.2123*** sample size 7,861 7,861 7,861 wald chi2(22) = 3,832.48 [six equation model] *p <0.05; **p <0.01; ***p <0.001. table 6. cross correlation coefficients. efficiency × efficiency rho21 efficient windows ↔ efficient appliances 0.2157*** rho31 efficient windows ↔ thrm insulation 0.5833*** rho32 efficient appliances ↔thrm insulation 0.2682*** renewable × renewable rho54 wind turbine ↔ ground source heat pump 0.7882*** rho64 ground source heat pump ↔ solar panel 0.5013*** rho65 wind turbine ↔ solar panel 0.5326*** efficiency × renewable rho43 thrm insulation ↔ ground source heat pump 0.3069*** rho51 efficient windows ↔ wind turbine 0.3504*** rho52 efficient appliances ↔ wind turbine 0.1951*** rho53 thrm insulation ↔ wind turbine 0.3766*** rho61 efficient windows ↔ solar panel 0.2639*** rho62 efficient appliances ↔ solar panel 0.1956*** rho63 thrm insulation ↔ solar panel 0.3489*** *p <0.05; **p <0.01; ***p <0.001. energy bill payment matters as households who their bills according to what the use as opposed to flat rate are more likely to invest in energy efficiency. the tenure effect aligns with the result of tovar (2012). households in this sample prefer to install energy efficiency measure earlier rather than later in their occupancy of the living home. income of households, age of reference person, knowledge of volume of energy consumed at home, living in detached houses or in rural areas only matter for selected technologies within the dimension. however, general social orientation matters for energy efficiency technologies whereas environment specific social 11 312 afr. j. environ. econ. manage. orientation (env ngo) does not matter for any equation in the energy efficiency dimension. with respect to table 5 determinants of investment in renewable energy are age, elders popular at home (share of age 55), energy use prudence (behaviour index), general and specific social orientation (ngo and env_ngo). in general, similar factors predict investments in both dimensions. however, important differences recorded in respect to age and social orientation. investors in renewable energy technologies are generally younger than investors in energy efficiency measures and tend to associate with both general and specific ngos. there is further heterogeneity separating the energy efficiency and the renewable technologies adopters: adopters of the energy efficiency technologies are likely to express difficulty coping with their current income but this is not observed for renewable energy adopters. that is to say that income constraints are operative with respect to energy efficiency investment but not with respect to renewable energy investment. this may reflect the effect of subsidies on investments since renewable energy technologies are more likely to be subsidized than energy efficiency investment (oecd, 2011). relationship between choice across the dimensions the correlation coefficient of the six equations in table 6 suggest positive relationships among all the investment choices. tests of significance was conducted on the correlation matrix and all correlation coefficients were found to be statistically greater than zero. although greater correlation is found within dimension, across dimensions the correlation is not positive nor negative. this suggest a complementary relationship between energy efficiency investments and renewable energy investments. households seem to engage in energy efficiency to save money and in renewable energy to satisfy intrinsic environmental affection. table 7 further explores the determinants of these relationships and identified education in terms of number of years of schooling after high school and in terms of the share of graduates in the home as contributory factors. there equally seem to be economies of scale among the factors: household size, share of children (share under 18) are positively associated with joint investment. on the other hand, tenure is negatively associated with joint investment. owners of their living home are less likely to jointly invest in energy efficiency and renewable energy. method of energy bill payment does not matter as well. conclusion and policy recommendations this study sets out to identify the factors that determine households’ joint adoption of energy efficiency and renewable energy technologies. in the process, technology specific determinants were estimated and the results show that the two dimensions of proenvironmental investment are determined by different sets of covariates. income constraints affect investments in the energy efficiency dimension but not the renewable energy dimension. the study found evidence for split incentives between home owners and renters and negative tenure effect for both dimensions. space availability in the living home matters generally for adoption of environmentally friendly energy behaviours. payment of energy bills according to use matters only for energy efficiency while households’ association with environmental ngo only matters for renewable energy investment. a complementary relationship between households’ choices of investment in energy efficiency and renewable energy technologies is suggested by this work: all correlation coefficients of the multivariate energy investment model were positive and significant with highest coefficient observed within rather than across dimensions. determinants of the joint investments was found to relate to education, economies of scale and social engagement in the form of association with nongovernmental organizations. owners are less likely than renters to jointly invest in both dimensions even though owners are more likely to invest in energy efficiency measures. joint investments in both dimensions decrease in length of staying the living home. this study suggests that when it comes to promoting energy efficiency technologies, subsidization policies could be effective since it was found that income constraint plays significant role in households’ adoption of these set of technologies. therefore, subsidization policies targeted at energy efficiency technologies should be effective. however, such policies if targeted at renewable or low penetrated energy efficiency investments may not be effective as they will be taken up by consumers who are not subject to income constraint. apart from economic incentives, since participation in ngo is positively associated with behaviour in all dimensions, raising awareness through informal channels could have effects on all the technologies irrespective of whether the technology is energy efficiency or renewable option. finally, the correlation of errors in any pair of the equations, in particular between energy efficiency and renewable energy technologies are significant and positive. this suggests that investment in one environmentally friendly energy technology increases the likeliness of investing in another. thus the interaction between households’ choices of environmentally friendly energy technologies should play a role in policy design. more effective policies should explore the knowledge that certain environmentally friendly energy investment can lead to heightened tendency to adopt other forms of environmentally friendly energy behaviour. specifically, positive correlations between pairs of energy efficiency 12 agwu 313 table 7. correlates of joint investment. variables investment rank log_income 0.00510 (0.00367) education 0.0152*** (0.00587) male -0.0610** (0.0256) married 0.00729 (0.0317) nocope 0.0194 (0.0274) share graduate 0.178** (0.0690) age -0.000658 (0.00144) hhsize 0.0287** (0.0145) share under_18 -0.134* (0.0724) share age55 0.0168 (0.0727) behaviour_index 0.0475*** (0.00750) ngo 0.149*** (0.0272) env_ngo 0.0765* (0.0427) log_floor 0.0494 (0.0303) owner -0.408*** (0.0305) dhouse -0.342 (0.00142) tenure -0.00421*** (0.00106) rural -0.0306 (0.0291) pay as you use -0.0755 (0.0507) kwatt_known 0.0903*** (0.0329) constant cut1 -1.811*** (0.165) constant cut2 -0.202* (0.164) constant cut3 0.297* (0.164) observations 9,784 pseudo r2 0.1064 country dummies included standard errors in parentheses *** p<0.01, ** p<0.05, * p<0.1 and renewable technologies suggest complementarity of the two forms of environmental behavior and should be explored in policies design. most previous models of environmental behaviour do not explore these correlations. such models are likely inefficient and lacking in essential information. future 13 314 afr. j. environ. econ. manage. research should focus on incorporating the nature of relationships 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(2011). analyzing consumer acceptance of photovoltaics (pv) using fuzzy logic model. renewable energy. appendix appendix a. country effects on technologies adoption. windows appl thrm pump wind solar aus -1.2555*** 0.0089 0.2093** -0.1193 0.3789* 0.5789*** can 0.0069 0.0268 -0.1751* -0.1196 0.2101 -0.4474*** che -0.0360 -0.1863** -0.1821* 0.4561*** -0.2699 -0.1256 chl -1.0360*** -0.8287*** -0.3760*** -0.73811*** 0.0052 -0.8388*** esp -0.0158 0.0214 -0.6808*** -0.255 -0.1287 -0.1511 fra 0.1669* 0.0657 -0.0607 0.1830 -0.0142 -0.1050 isr -1.0317*** -0.2225*** -0.5013*** -0.0788 -0.0154 1.9455*** jpn -0.8022*** -0.5244*** -0.6022*** -0.7463*** -1.0694** -0.3527** nld 0.5705*** -0.2308*** 0.1299 -0.3566* -0.2786 -0.236* swe -0.2244** -0.1248 -0.3278*** 1.0185*** 0.1639 -0.3421** *p <0.05; **p <0.01; ***p <0.001. african journal of environmental economics and management vol. 1 (5), pp. 153-166, december, 2013. available online at www.internationalscholarsjournals.org © international scholars journals full length research paper market and welfare economic impacts of sustainable forest management practices: an empirical analysis of timber market in peninsular malaysia as abdul-rahim 1 *, ho mohd-shahwahid 1 , s. mad-nasir 2 and ag awang-noor 3 1 faculty of economics and management, universiti putra malaysia, 43400 serdang, selangor, malaysia. 2 faculty of agriculture, universiti putra malaysia, 43400 serdang, selangor, malaysia. 3 faculty of forestry, universiti putra malaysia, 43400 serdang, selangor, malaysia. accepted 13 april, 2013 the main objective of this study is to analyze the impact of sustainable forest management (sfm) practices on the timber market in peninsular malaysia. a partial equilibrium model was applied in this study covering domestic timber market namely supply and domestic demand of timber. it was analyzed by using a system of equations approach. all data were compiled from published sources of malaysian government publications namely from the department of statistics and annual report of the forestry department of peninsular malaysia. all of the data are annual time series basis from 1970 to 2008. impact analysis was conducted based on three scenarios that arise from sfm practices (that is (1) reduced by 24% in harvested area, (2) increased by 74% in external cost of timber harvesting and (3) increased by 47% in the cost of internalization the externalities). these scenarios will be incorporated in the timber market model. results show that changing from the conventional logging (cl) practices to sfm practices reduce the equilibrium quantity of timber and increase the price level. the welfare economic impacts of sfm provide empirical evidence that there is a loss in welfare economic impacts on the timber industry in peninsular malaysia. however, an increase in the domestic price of timber would help to compensate for the loss volume of timber. the state government and any related agencies should be able to use these results as a reference to come out with good mechanisms in strengthening the effectiveness of sfm policy. hence, they should be able to assist domestic timber industry by supporting them to fetch various potential incentives such as price premium, carbon credit and market access for timber produced from sustainably managed forest. key words: consumer surplus, producer surplus, equilibrium price, equilibrium quantity. introduction according to kumari (1995), when we are discussing about sustainable forest management (sfm), it should cover all mechanisms of allocation and not focused on market only. however, there are many situations and resources which are not and cannot be allocated by market mechanism. for example, many cultures, including indigenous people, use non-market mechanism for resource allocation. this does not mean that their resource allocation is not at optimal level. similarly, with regards to carbon sequestration, nationally or globally would enjoy the benefit of clear atmosphere received from the carbon storage which cannot traded in the market. however, nowadays, there is a term known as carbon credit created by economists assigning values on carbon for trading in the market. in malaysia, kumari (1995, 1996) conducted a study of total economics valuation (tev) approach in the context of conventional logging (cl) and sfm practices. the *corresponding author. e-mail: abrahim@econ.upm.edu.my. tel: +6019-2090970. fax: +603-89486188. abdul-rahim et al. 153 table 1. forest of goods and services valuation under cl and sfm practices. goods/services method/variable location value estimated (rm/ha) source analysis cl sfm total social benefitsa tev malaysia 627 1,118 total global benefitsb tev peninsular malaysia 8,389 9,146 kumari, 1996 carbon storage tev peninsular malaysia 8,049 8,677 water cost of water treatment peninsular malaysia 704 1,477 mohd shahwahid et al., 1999 timber and non-timber cost-benefit (npv) sarawak 9100 9905 dagang et al., 2005 watershed protection npv peninsular malaysia 1,019 1,060 mohd rusli, 2002 forested catchment npv peninsular malaysia 1,006.1 740.7 mohd rusli, 2002 a hydrological, rattan, bamboo, recreation, domestic water and fish; b endanger species and carbon stock. tev involves use value, non-use value, direct use value, indirect use value, option value, existence value and quasi-option value. in general, editorial (2007) mentioned that the concept of sfm in the context of economics is the study of the socially optimal allocation of scarce resources. this means the economics study is not limited to the study of markets, marketed resources, market signals of scarcity, and market mechanisms of resource allocation but it also includes the study of all resources, marketed and non-marketed; all categories (aboriginal, ecological, environmental, legal, social and market) of resource scarcity signals; all mechanisms, including market, social, legal, and political, of resource allocation; and intra and inter-generational equity as part of social optimality. table 1 indicates several goods and services with respect to the economic value estimated from the two types of forest management practices namely conventional logging (cl) and reduced impact logging (ril) practices where ril is also represent the implementation of sfm practices. both cl and ril deal with the impacts of the forest management practices on goods and service of the forest multiple functions through economic analysis. economic analysis is referring to the social effects or externality effects that might occurred due to timber harvesting operations. for example, some of these include hydrological, rattan, bamboo, recreation, domestic water, fish, endanger species and carbon storage. the full valuation of forest goods and services would yield surpluses for countries to invest in and achieve sfm. owing to the externality effects, sfm policy is in favor to provide greater positive externality effects compared to cl practices. for example, in table 1, kumari (1996) found that at national benefit, the total social benefits under cl and sfm are rm627/ha and rm1,118/ha respectively. this has also increased the global benefits from rm8,389/ha to rm9,146/ha under cl and sfm respectively. in addition, mohd shahwahid et al. (1999) revealed that the cost of treating the water is lower under sfm practices with less externality effects. this study will not only analyze the determinant of peninsular malaysia timber market, but also internalise the externality effects in the systems analysis. for example, to minimizing the externality effects from timber harvesting operations, the additional activities and procurement are really needed. this will lead to increase in the operational cost. a study by abdul rahim et al. (2009b) revealed that the operational cost has increased by 47% due to additional activities that may minimise the externality effects. in addition, the incremental cost of treating water due to timber harvesting will also incurporate in this analysis. this is because it could consider as externality effects as the third party namely water treatment plant has to bear higher cost in treating the water resulting from timber harvesting. one recent study by abdul-rahim and mohd-shahwahid (2010) showed that the cost of water treatment has increased by 74% due to timber harvesting activities. this is crucial issues need to be analyze and discuss because if there is a significant distortion in the market, government intervention is one of the solution to easy the problem. to make it clear, timber market in this study is also known as log market. most of previous studies on timber market analysis typically deal with the prices, supply and demand in domestic and international market. however, to the best of authors’ knowledge, none of the study analyzes timber market that internalizes the value of price and quantity as the value that already incorporated the externality effects. for example, a current domestic timber prices in peninsular malaysia is just determined by the market driven. it is expected that by internalizing the externalities, the price is potentially higher than the current prices. hence, government intervention is really needed to correct the distortion. in this context, this present study will provide some output of analysis that could be used by the government for policy decision making. therefore, the optimum level of output and price at externality level will be quantified because the net benefit is maximized when it takes into account the negative externality effects as well (tietenberg, 2003). in a view of malaysian case, malaysian government has given its priority to manage the forest with sustainable manner which refer to sfm practices. in recognition 154 afr. j. environ. econ. manage. to the need of strengthening sfm, malaysia has undertaken a critical step to reduce the annual coupe or aac in the country (woon and tong, 2004). consequently, the aac has been reduced from 52,250 ha per annum for peninsular malaysia during the sixth malaysia plan (1991 to 1995) to 46,040 ha per annum during the seventh malaysia plan (1995 to 2000). this reduction continues during the eight malaysia plan (2001 to 2005) and ninth malaysia plan (2006 to 2010) to 42,870 ha and 36,940 ha respectively. looking at the actual number of timber that has been extracted, it is shown that the total volume of timber extracted is lower than the aac approved during eight malaysia plan at 37,326 ha instead of 42,870 ha. furthermore, on the marketing front, the supply of malaysian timber has been declining; mainly due to the malaysian commitment to sfm practices (jamal and mohd shahwahid, 1996; tan et al., 2003). this planned reduction in logging rate helps to ensure the extraction of forest resource is in line with the sustainable capacity of the forests. a downward trend in available supply which referred to aac has put considerable pressures to the local production of timber as well as other wood products. as mentioned by lim et al. (2002), the declined in timber production was mainly due to the reduction of annual coupes resulting from the rio convention and malaysia’s need to achieve itto objectives 2000 and international certification standard in attaining sfm. therefore, if all of these conditions are followed successfully, it would further reduce the supply for domestic consumption. it will be even more worrying, when the accessible forestland in malaysia is slowly given a way to agriculture especially in oil palm, new satellite towns and other forms of land use, creating a conflict between agriculture production and forest management (ahmad fauzi, 2005). beside the aac has been reduced, the stringent criteria of sfm on harvesting operation has affected the timber volume that can be extracted from forests. consequently, malaysian timber supply has been continuously diminished. for example, timber production from peninsular malaysia natural forests has been decreasing steadily. according to forestry department of peninsular malaysia (2008), the statistic shows that timber production decreased from 12.8 million m 3 in 1990 to 4.0 million m 3 in 2008. most of the studies conducted either locally or abroad revealed that there is incremental cost in operating sfm other than the reduction in timber production (schwarzbauer and rametsteiner, 2001; ahmad fauzi et al., 2002; linden and uusivuori, 2002; woon and tong, 2004; abdul rahim and mohd shahwahid, 2009a). all of these possible changes are directly related on harvesting regulations and additional guidelines on timber harvesting activities. hence, this will reduce the volume of timber which can be extracted from forest as well as incurred higher cost. in other words, in the short run, it may reduce potential harvesting volumes and producers may have to bear higher cost in implementing sfm. however, in the long run, this may support a sustainable level of production that will exceed of what would be possible in later years if environmentally harvesting systems were to be continued (thang, 2007). beside the issues of operation cost and timber production, several other elements in sfm that potentially give direct impact to the timber market are also identified; such as price premium and market access. with regard to the economic reasons, timber producers must acknowledge that there are some economic advantages to participate in sfm. with the above issues rose relating to the malaysian timber industry, it is paramount that the market is to be understood in term of the relationship of its major parameters. it has become essential to know the various impacts of sfm practices on timber market in peninsular malaysia. this is where we have to come out with several scenarios of sfm practices and carry out simulations analysis for examining the market and welfare economic impacts. methodology and data while there are different issues in forest sector policies analysis, the analytical framework is quite similar. the common approach is to develop a forest sector model and to simulate the impacts of the policy on the timber and product markets for domestic or international markets. a typical model building involves the estimation of output consumption, price and trade of the timber products. the impacts of the policies were evaluated by comparing the simulated results for with and without policy scenarios. studies on forest related policies such as kallio et al. (1986), menurung (1995), schwarzbauer and rametsteiner (2001), barbier et al. (1995), ismariah (2001), mohd shahwahid (1993, 1995), mad nasir and mohd shawahid (1995) and ahmad fauzi (2005) have used such framework. a review on their analytical framework is useful, as this study will address most likely similar policy questions relating to certain policy approach. however, this paper differs as it takes into account the sfm policy by incorporating with several scenarios of sfm practices namely (1) reduced by 24% in harvested area, (2) increased by 74% in external cost of timber harvesting and (3) increased by 47% in the cost of internalization the externalities. in other words, the current input cost of timber harvesting operation has to incorporate together with the cost that is related to the externalities. this is where most of the prior studies have ignored the externality effects in their econometric modeling. overview of the model structure the underlying objectives of this study as discussed earlier focused on the internalization of externality effects on the analysis of timber market in peninsular malaysia. figure 1, illustrates the flow of the economic impact analysis with respect to the objectives of study and the analysis approach. in this study, there are two major steps of impact analysis. the first step is to estimate the peninsular malaysia timber market model. the second step is to analyze the market and welfare economic impacts by incorporating several scenarios under sfm practices. in sum, both analyses are important to investigate the impact of the implementation of sfm practices on the timber industry. the logic of the economic analysis is rather simple. if the forested area is manage according to the sfm practices, it will abdul-rahim et al. 155 economic impact analysis market effects welfare effects incorporating with several scenarios under sfm; 1. reduction in harvested area 2. incremental cost of internalization the externalities 3. external cost of timber harvesting (externalities) 4. market access system of equations approach simulation analysis baseline scenario sfm scenario figure 1. economic impact analysis schematic diagram. harvesting from natural forest timber total timber supply domestic industrial domestic export international industrial needs demand demand needs from less forest endowed countries figure 2. schematic diagram of timber supply. affect several economic elements such as harvested area, operational costs, price and market. changes in these elements influence the economics of timber supply and demand. the model analyzes the impact of these shifts in timber supply and demand on key variable such as the production and consumption of timber market. several impacts under sfm scenarios are simulated by linking them into peninsular malaysia timber market model. peninsular malaysia timber market model this study adopted and modified the model developed by kumar (1981, 1983), kinus (1992), mohd shahwahid (1993, 1995), mad nasir and mohd shahwahid (1995), ismariah (2002), ahmad fauzi (2005) and abdul rahim and mohd shahwahid (2009a). timber that comes from natural forests will be analyzed in this study. the schematic diagram (figure 2) not only shows the flow of production of timber but also insist on developing the model. there are timber supply, domestic demand and export demand in the diagram. however, import demand export demand was not considered in this study. this is because malaysia is not fully relying on imported timber particularly for peninsular malaysia and its export of timber has been banned since 1990s. the detailed justifications will be 156 afr. j. environ. econ. manage. explained in the next section. supply of timber from natural forest the timber supply from natural forest is given by the equation: lnts t = 0 + 1 lnp t + 2 lnah t + 3 lnic t + 4 lnts t 1 + t (1) where: ts t = supply of natural forest timber p t = price of timber ah t = harvested area in natural forest ic t = total salaries and wages paid in logging industry ts t 1 = lag supply of timber supply by one year t = years  t = error term ln = natural logarithm equation 1 estimates the total supply of timber from natural forest, which should be positively related to the natural forest timber prices and harvested area in natural forest. tst is the supply of natural forest timber as endogenous or dependent variable; pt is the price of natural forest timber, which is an important variable in determining the quantity of natural forest timber supply; aht is the natural forested area open for harvesting; ict is total salaries and wages paid in logging industry represents to the production cost; ts t 1 is previous year natural forest timber supply, which have influenced the natural forest timber supply. incorporation the cost of internalization the externalities and external cost input cost under the scenario of sfm = input cost + cost of internalization the externalities (2) input cost under the scenario of sfm = input cost + external cost of timber harvesting (3) equations 2 and 3 explain the situation where the timber market model is incorporated with the cost of internalization the externalities and external cost. incorporation those elements are crucial, otherwise it can lead to market failure. market failure associated with the externality effects resulting from timber harvesting activities in forest. without taking into account the externality effects, the timber production from natural forest could be considered as being managed without sustainably produced. in other words, it cannot achieve the optimum level of quantity and price of timber. most of previous studies especially studies using econometric modeling had ignored the external cost in their research. therefore, this study tries to incorporate with that element so that the research outcome could represent the optimal level estimation of quantity and price in timber market. demand of timber from timber processing mills lndd * t = 0 + 1 lnp t + 2 lnipi t + 3 lnwmp t + 4 lndd t 1 + t (4) where; dd * t = domestic demand for timber p t = domestic price for timber ipi t = industrial production index wmp t = world import price of timber dd t 1 = lag of domestic demand for timber for by one year t = years  t = error term ln = natural logarithm equation 4 describes the estimated total domestic demand for timber from natural forests. it suggests that the lower the price offer, the higher the volume of forest timber demanded domestically. on the other hand, the higher world import price of timbers would encourage further consumption of domestic timbers. similarly, the higher industrial production index (ipi) would promote timber processing mills (that is sawmills, plywood and veneer mills) to demand more domestic timbers. instead of using malaysian income, ipi will be used in this study because the timber demand is considered as intermediate goods. ipi is also used to measure the economic growth of the timberbased manufacturing industries and it should therefore be positively related to the timber demand. when there is a growth in timber processing mills, demand for timbers would rise but domestic demand would have to compete with other substitute such import of timber. hence, we used world import price of timber (wmp) which represents substitute good. it suggests that the higher the wmp, the higher the volume of domestic demand of timbers. lndd * t is the dependent variable for domestic demand for timber, which is influenced by the domestic price of timber (p t ), industrial production index (ipi t ), world import price of timber (wmp t ) and the previous year’s domestic demand of timber (dd t 1 ). closing identities (total supply of timber) the above timber market model has two main equations. to close the system, an identity equating timber availability with domestic demand of forest timbers is postulated as follows: tst=ddt (5) to analyze the timber market model, this study estimates timber supply and demand for domestic market. then, re-estimate the supply and demand simultaneously followed by simulation analysis of several scenarios under the sfm practices. the domestic supply and domestic demand equations will be estimated by system of equations approach. from equation 5, a partial equilibrium of quantity and price of timber can be generated. the details calculation can be seen in appendix a. in addition, the producer and consumer’s surplus that represents welfare economic impacts are also being quantified. welfare economic impact analysis the effects on the timber sector from several scenarios under sfm abdul-rahim et al. 157 price p2 s1 s0 c p1 b p e f 0 d0 q1 q quantity figure 3. change in consumer and producer surplus from shift of timber supply in domestic market. practices namely reduction in harvested area, incremental cost of internalization the externalities and external cost of timber harvesting operations can be explained by the changes in the aggregate consumer and producer’s surplus. consider the timber market in figure 3, the market demand curve for timber is simply the horizontal summation (that is, summation n along the quantity axis) of the demand curves of each individual timber processing mills (sawmills, veneer and plywood mills). the aggregate price value of a given quantity of timber will be equal to the area under the market demand curve and the height of the market demand curve is equal to the price value of each unit of timber. for example, the total value of q units of timber is equal the area op2bq. but, if the commodity could be purchased at price p, the total cost of q units to the consumer would be only the area opbq. since the total cost would be less than the total value to the consumer, timber processing mills would realize a net gain referred to as consumer’s surplus equal to the difference area pp2b. similarly, the market supply curve for timber is the horizontal summation of the supply curve for all mills in the industry. the height of the supply curve for timber is equal to the opportunity cost of each unit of timber, since the height of a firm’s supply curve indicates the price value of the marginal opportunity cost of each unit of the commodity. the price paid for inputs by the industry reflects the opportunity cost of the last unit purchased. the area under the market supply curve for timber will therefore be equal to the total opportunity cost of the inputs used by the industry to produce timber. then, the difference between the total revenue received by an industry and the area under the market supply curve for timber is equal to the total producer’s surplus received by the timber supplies in that industry. in summary, the aggregate consumer’s surplus is equal to the area under the market demand curve and above the market price line, area pp2b. in turn, aggregate producer’s surplus is equal to the area above the market supply curve and below the price line, area pbf. the price value of the benefits and costs resulting from the shift of the supply curve for timber in the domestic market can be calculated using the concepts of consumers and producer’s surplus discussed previously. as illustrated in figure 3, the reduction in available cut and increases in cost of internalization the externalities and external cost of timber harvest would reduce timber supply. the supply curve before the policy is labeled s0, and the total consumer and producer’s surplus is equal to the area fbp2. hence, the supply curve shifted to s1, and the total consumers and producer’s surplus is equal to the area ecp2. therefore, the shift in the supply curve for timber from s0 to s1 would result in a decrease in total consumers’ and producers’ surplus equal to the area bcef. the total sum of the consumer and the producer surplus is the social surplus. at this level, the value of consumer and the producer surplus were represented the value after taking into account several scenarios under sfm practices. evaluating the time series properties it has become a standard practice to begin the analysis by examining the time series properties of the data. any time series data can be thought of as being generated by a stochastic or random prices and a concrete set of data. a stochastic process is said to be stationary if its mean and variance over time and the value of covariance between two time periods depends only on the distance or lag between the two time periods and not on the actual time at which the covariance is computed. with these particular characteristics, shocks to a stationary time series would be; over time, the effect of the shocks will dissipate and the series will revert to its long run mean level. consequently, long-term forecasts of a stationary series will converge to unconditional mean of the series. in contrast, a non-stationary series process has a permanent component. its mean variance is time independent. for a nonstationary series, there is no long-run mean to which the series returns. we start the analysis by examining the time series properties of the data used in the supply and demand equations. however, depending on the power unit root tests, deferent tests might yield different results which eventually lead to certain degree of uncertainty in the analysis of level relationships. therefore, this table 2. results of timber market. supply function ∆lnts = 1.7281 + 0.1497∆lnp 0.0828∆lnic + 0.2076∆lnah + 0.9531∆lntst-1 (0.05)* (0.07)* (0.00)*** (0.00)*** r 2 = 0.93 adj. r 2 = 0.92 dw = 1.93 ramsey reset test = (0.33) heteroscedasticity test = (0.63) wald test = (0.00)*** demand function ∆lndd = 4.2010 0.3687∆lnp + 0.2792∆lnipi + 0.3216∆lnwmp + 0.6758∆lndd t-1 (0.05)* (0.20) (0.12) (0.00)*** r 2 = 0.73 adj. r 2 = 0.69 dw = 1.88 ramsey reset test = (0.61) heteroscedasticity test = (0.73); wald test = (0.00)*** study utilize two different unit root testing procedures in examining the stationary properties of the data to provide a robust test result on the information of the order of integration of the data used. the use of alternative unit root testing procedures is very important in dealing with anomalies that arise when the data are not very informative about whether or not there is a unit root. these two unit root tests used are the non-stationary test of augmented dickeyfuller (adf) and philips-perron (pp) unit root test. data description the data used in this analysis is time series data. with regards to the time series data analysis, this study intends to evaluate the empirical performance of sfm practices in peninsular malaysia domestic market using annual data from 1970 to 2008. published data on all variables in this study were available from the forestry department of peninsular malaysia, department of statistics, malaysia and ministry of plantation industries and commodities, malaysia. empirical results econometric analysis is capable of providing a quantitative analysis of the actual economic phenomenon based on the concurrent development of theory and observation, related by an appropriate method of inference (gujarati, 2003). since this analysis uses time series data, it is necessary to find out whether the data are stationary or otherwise. for this reason, unit root test has been conducted using the adf and pp unit root test. unit root test on time series data it is necessary to test the order of integration of each variable in a model. this is to determine how many times the variables need to differently produce a stationary series. it is essential to note that testing for stationary condition for a single variable is very similar to testing whether a linear combination of variable cointegration to form a stationary and equilibrium relationship (harris, 1995). since the unit root test results are sensitive to different values of the autoregressive lag lengths, the selection rule of the truncation lag parameter is crucial in determining the order of integration of the data. in this study, the optimal lag length of the adf test is chosen based on automatic selection by schwartz information criterion (sic), while newey-west bandwidth criterion is used for the optimal lag length selection in the pp test to ensure the errors are white noise. all the unit root tests are carried out using e-views 6.0 software. all the variables are non-stationary in levels. thus, we cannot reject the null hypotheses of a unit root in both the adf and pp tests. on the other hand, all series appear to be stationary after first differencing that is i (1). this result is consistent for both adf and pp tests used in this study. therefore, higher order of differencing is not required to make the data into stationary process. the results imply that there is i (1) variables in the peninsular malaysia data, and no existence of i (2) variable. there is a concrete support for the existence of a unit root stationary at i (1) by adf and pp unit root tests in peninsular malaysia. the result of i (2) is automatically do not need to carry out because all the variables are integrated at i (1). if, there are not integrated at i (0) and i (1), then it is necessary to analyze the unit root test at i (2) level. estimated coefficients of timber market table 2 provided the empirical result of the estimated equations. as mentioned earlier, the supply and demand models for the timber industry were estimated using the system of equations approach as endogenous variable exists in each of the equation. based on the result of unit root tests, all parameters used in the model are stationary at first difference. therefore, the data are not stationary at level form; it should be transformed to the first difference before importing those variables in the model. in general, the estimated equations in the model have reasonable goodness-of-fit. all of the variables 158 afr. j. environ. econ. manage. abdul-rahim et al. 159 coefficients in the model were as expected and consistent with the theory of supply and demand. based on the empirical result of timber supply function, the estimated coefficients of p and ic were statistically significant at the level of 10%. this means that, they are the significant determinants of timber supply. for p, the result suggested that for every 10% growth in average p, ceteris paribus, timber supply would increase by 1.5%. the significant coefficient of p verified the priori assumption that price is an incentive for timber production. on the other hand, ic has a negative coefficient. based on the estimation, a growth of 10% in ic, ceteris paribus, the timber supply would decrease by 0.8%. in other words, larger value in ic will then reduce the volume of timber produced. ah on the other hand appeared to be highly significant at the level of 1%. this is believed to be due to the direct impact of timber harvesting activities on timber supply. thus, a 10% reduction in ah led to approximately 2% decrease in timber supply. this is where the malaysian government has taken a proactive action when the rate of aac shows declination since early 1990s. this to a certain extent may pull down the timber supply to a sustainable level. this result is similar with the study conducted by jamal and mohd shahwahid (1997) and lim et al. (2002) which concluded that the malaysian strategy to reduce aac in the natural forest is in preparation towards sfm practices. for example, jamal and mohd shahwahid (1997) mentioned that timber supply started declining from 1992 onwards due to the practice of sustainable forest management. the estimates obtained for the domestic demand equation were as expected. the coefficients for own price and lagged one year dependent variable were significant at the level of 5% and one percent respectively. the own price elasticity is -0.389. this result confirmed the findings of previous studies (mohd shahwahid, 1995; abdul rahim; mohd shahwahid, 2009e) that the domestic demand and supply for timber price is inelastic. a 10% growth in the price of timber decreases the domestic demand for timber by 3.8%. similarly, daniels and hyde (1986) reported that both supply and demand price were fairly inelastic and suggested that price changes will not result in dramatic harvest fluctuation. conversely, the coefficients for substitute price and industrial production index were not significant. the industrial production index does not influence the demand for timber (mohd shahwahid, 1995). the insignificant result of the substitute price (that is, world import price) implied that the domestic timber market in peninsular malaysia do not really rely on imported timber. in the case of peninsular malaysia, there was no export market for timber since early 1990s. according to fdpm (2005), peninsular malaysia has imposed a ban on timber export since the 1990s. this action was taken to give local timber processing mills priority in getting their raw materials and also to meet the domestic demand. any export has to be processed timber. in addition, peninsular malaysia has marginally imported timber from abroad. for example, in 2007, peninsular malaysia has imported 70,704 m 3 of timber or 1.6% out of the total supplied. hence, the total quantity supplied and demanded can be solved within the domestic market as a large portion of these quantities were not from the foreign market. this is a reasonable explanation for the exclusion of international timber market in the partial market equilibrium analysis. in other words, this study will focus on the impact of domestic market and economic welfare, for the case of peninsular malaysia. validation of timber market model the overall fit of the equation between the explanatory variables and dependent variable could be explained by the value of r-square. this is an important criterion in evaluating the quality of regression. for example, the value of r-square obtained from the estimated supply equation is 0.93. this implied that 93% of the variation in timber supply can be explained by the explanatory variables in the model. other diagnostic tests that have been carried out for timber supply and demand equations were serial correlation of durbin-watson (dw) test, heteroscedasticity, ramsey reset test and wald test (table 2). the results of dw and heteroscedasticity tests have shown no evidence of serial correlation and heteroscedasticity problems. the ramsey reset test has proven that the equation is stable and has no functional misspecification. the wald test is important to test whether the estimated equations have a long run relationship between independent and all explanatory variables. the result showed that the model is cointegrated at the significant level of 1%. the root mean square error and theil inequality test demonstrated that the deviation of simulated variables is quite close to the average size of the variable in the equation. a historical simulation has been carried out in the sample throughout the period of this study. this is where the adequacy of the model in forecasting and policy analysis. the detailed tests and results were depicted in table 3. the root mean square error (rmse) and theil’s inequality coefficient were found to be relatively small for timber supply (ts) and domestic demand (dd). this result suggested that the forecasting and policy analyses can be considered as accurate. the value of bias proportion is equal to zero, indicating the non-existence of a systematic bias for ts and dd. figure 4a and b showed the actual, fitted and residual graphs of the timber supply and demand equations. this result provides strong evidence that the equation is stable between the dependent and all independent variables. table 3. historical simulation of timber model. ts dd root mean square error 0.08 0.10 theil’s inequality coefficient 0.002 0.003 bias proportion 0.000 0.000 variance proportion 0.03 0.019 covariance proportion 0.96 0.98 16.4 16.0 15.6 .2 15.2 .1 .0 14.8 -.1 -.2 -.3 1975 1980 1985 1990 1995 2000 2005 residual actual fitted a 16.4 16.2 16.0 15.8 .4 15.6 .2 15.4 15.2 .0 -.2 -.4 1975 1980 1985 1990 1995 2000 2005 residual actual fitted b figure 4. simulation of timber supply and demand. results of price and quantity equilibrium table 4 presents the empirical results of the average simulated value calculated from the timber partial market equilibrium model for the period of 1995 to 2008. during this period and thereafter, the sfm/ril has been implemented in the malaysian forest management. since this study examined the economic impact of sfm practices, this study will only averaged out the data for the period of 1995 to 2008 from the simulated output for further analysis. as mentioned earlier, the impact analysis comprised of three scenarios; (1) reduced by 24% in harvested area, (2) increased by 74% in external cost of timber harvesting, and (3) increased by 47% in the cost of internalization the externalities. the percentage of the reduction in harvested area was 160 afr. j. environ. econ. manage. table 4. average simulated values due to sfm practices. parameter equilibrium quantity equilibrium price (m 3 ) (rm/m 3 ) baseline scenario scenarios % changes under sfm practices reduced by 24% in harvested area rise by 74% in external cost of timber harvesting rise by 47% in the cost of internalization the externalities 6,655,871 514 6,392,684 573 6,442,272 561 6,506,564 546 adopted from the study conducted by ahmad fauzi et al. (2002). whereas, the remaining two scenarios (that is, incremental cost of internalization the externalities and incremental cost of external cost of timber harvesting activities) were borrowed from the study conducted by abdul rahim et al. (2009) and abdul rahim and mohd shahwahid (2010) respectively. the incremental external cost of timber harvesting activities and the cost of internalization the externalities by minimizing damages from timber harvesting activities will result in optimum level of quantity and price level. in this impact analysis, the equilibrium price was calculated from the estimation of timber market model, where the market equilibrium was set-up. by definition, the equilibrium price is the price at which the supply of timber equals the demand for timber (equation 5). after substituting the equilibrium price into the supply or demand model, the equilibrium quantity was obtained. in other words, from the estimated coefficient, the equilibrium price and quantity of timber could be quantified. the detailed processes are available in appendix a. the average timber market equilibrium point for price and quantity was rm514/m 3 and 6.65 millions m 3 respectively. this point corresponds with the baseline scenario. the incorporation of the three impacts of sfm practices; (1) reduction in harvested area, (2) incremental external cost of timber harvesting activities and (3) incremental cost of internalization the externalities by minimizing forest damages from timber harvesting activities through simulation analysis, showed negative effect upon equilibrium quantity. on the other hand, the price of timber showed positive effect as it increased under the three impact scenarios from sfm practices. as shown in table 4, the price of timber increased by 12, 9 and 6% to rm573/m 3 , rm561/m 3 and rm546/m 3 respectively under the three scenarios of sfm practices. this reflected the domestic timber market in peninsular malaysia that potentially may fetch price premium averaging from 6 to 12% if the three potential impacts were imposed on timber producers. in other words, these simulated prices were the price of timber when best practice environmental resource management was adopted and when price distortion was remedied. this finding is consistent with the result obtained from the previous studies. some authors claimed evidence that consumer in europe and usa were willing to pay between 2 to 30% more for sustainably produced certified tropical timber (baharuddin, 1995; baharuddin and simula, 1996; simula and baharuddin, 1996; oliver, 2005). in addition, kollert and lagan (2007) carried out their study in selected forest management units (fmus) in sabah, malaysia and found that sabah timber achieved a price premium averaging from 2 to 56%. based on this empirical analysis, the advantage of complying with sfm practices in peninsular malaysia is the increase of domestic price of timber, averaging from 6 to 12%. this is where malaysian government intervention is needed to ensure that the advantages of price premium in the domestic market can be realized; particularly, the timber produced from sustainably managed forest. as seen in table 4, the equilibrium quantity of timber has decreased by 4, 3 and 2% to 6.39 m 3 , 6.44 m 3 and 6.51 m 3 respectively under the three scenarios of sfm practices. this finding is consistent with the study conducted by schwarzbauer and rametsteiner (2001) which revealed that the timber production will decrease in the long run due to sfm practices. this implied that the domestic timber processing mills might rationalize their consumption of timber as raw material from natural forest by being more efficient processors. those who could not upgrade or switch towards the more efficient production practices may have to close down, while those who can may expand their production base. in addition, woon (2001) revealed that the total number of timber processing mills (that is, sawmills, plywood and veneer mills) were expected to be drastically reduced due to sfm practices. the result of this study provides an empirical evidence of the implication under sfm scenarios on timber market in peninsular malaysia. the percentage of decreases in equilibrium quantity of timber in the long run provided an explanation that the malaysian timber production was managed not only for present needs but also for the benefits of the future generation as well. furthermore, the timber harvesting technique in sfm practices that gave abdul-rahim et al. 161 162 afr. j. environ. econ. manage. table 5. average welfare impacts due to sfm practices. item producer surplus consumer surplus total social benefits baseline scenario 88,225 118,224,286 118,312,541 reduced by 24% in harvested area scenarios % rise by 74% in external changes under sfm cost of timber harvesting practices rise by 47% in the cost of internalization the externalities 67,347 118,122,972 118,190,319 68,364 118,143,237 118,211,601 75,799 118,168,669 118,244,468 priority in curbing externality effects and logging damages enhanced the process of regeneration of timber tree in the next cutting cycle. in this context, thang (2007) revealed that the malaysian timber production would increase in the long run due to the implementation of sfm. results of welfare economic impacts based on the simulated value calculated earlier as given in table 4, the average annual estimated values of welfare economic impacts were further calculated (table 5). the similar scenarios as what in the market impact analysis were adopted and simulated in this welfare economic impacts analysis. the simulation results showed that the calculated value of producer surplus and consumer surplus changes when incorporating the three scenarios under sfm practices. the detail process can be seen in appendix b. under scenario one, where ha reduced by 24%, the producer surplus reduced from rm88,255, under the baseline case to rm67,347. similarly, the consumer surplus also decreases from rm118.22 million, under the baseline scenario, to rm118.12 million. under scenario two, where external cost of timber harvesting increased by 74%, the producer surplus reduced from rm88,255, under the baseline case, to rm68,364. similarly, the consumer surplus also decreased from rm118.22 million, under the baseline scenario, to rm118.14 million. under scenarios three, where the cost of internalization the externalities went up by 47%, the producer surplus reduced from rm88,255, under the baseline case, to rm75,799. similarly, the consumer surplus also decreases from rm118.22 million, under the baseline scenario, to rm118.17 million. this result indicated that the variation in the ha is the main cause of reduction in the calculated value of the producer and consumer surplus. this is because the elasticity of ha was relatively higher than the other policy variables. this situation would bring towards loss in the economic welfare on timber market in peninsular malaysia. the economic welfare in this study referred to the calculated value of total social benefit, which is the summation of the value of producer and consumer surplus. hence, this finding implied that when the timber industry complies with the sfm practices, the economic welfare of the stakeholders in the timber sector will decline. as noted by wells and wall (2005), there is an element of trade-offs between environmental protection and timber from forests. however, with sfm practices, the source of timber supply from natural forest could be sustained and the externality effects from timber harvesting activities could be minimized. otherwise, the regeneration of timber from the natural forests would be affected. in general, the nation would also lose the valuable non-timber forest products (ntfps) and environmental services that could potentially generate income for the society and government in the future. in addition, kotwal et al. (2008) claimed that sfm practices could enhanced the growing stock of timber and forest productivity of timber and non-timber forest produce. conclusions the above findings showed that such ha and ic behaviors may have significant impact on the future equilibrium price and quantity process, which in turn affects the welfare of producers and stakeholders in the timber-based industry. on the supply side, the results showed that compliance with sfm practices will reduce the supply of timber to a sustainable level. however, the level of price was pushed up in the partial equilibrium process. hence, the equilibrium price and quantity of timber have increased and decreased respectively, representing the optimum level in internalizing the externalities from timber harvesting activities. for the case of peninsular malaysia, the simulation showed that the market and welfare economic impacts arising from sfm practices were small. based on those abdul rahim et al. 163 scenarios, a decrease in harvested levels were likely to context, the common method that has typically been used affect the market and economic welfare more than an is an input-output model. the coefficients estimated in increase in input costs (direct and indirect) owing to sfm the econometric model could be used in the input-output practices. this result is similar with the study conducted (i-o) model to measure the total economic impact for the by schwarzbauer and rametsteiner (2001). they found whole economy. in addition, the i-o model is also that any decrease in harvested levels gave an immense capable to take into account the importance of inter impact on forest products market than any increase in the dependencies that exists between sectors in an operational costs due to sfm practices. economy. then, the direct and indirect impacts of sfm the simulation results of partial market equilibrium prepractices could be highlighted. sented above revealed that producers could potentially (2) this study only analyzes the economic impact of sfm fetch price premium in the domestic timber market in practices on timber market as it gave direct impact to the peninsular malaysia. in this context, one should expect timber harvesting activities. however, it would be wise for that timber producers will choose to comply with the sfm decision makers to further conduct the economic impact practices if the price is an incentive. therefore, the price analysis of sfm practices on timber-based industries such as premium is required to offset the foregone value of two sawntimber, plywood, pulp and paper, veneer and moulding. elements considered in this study; (1) incremental cost of this could be done through individual analysis which internalization the externalities by minimizing the environanalyzes the types of timber-based industries by using econometric model. alternatively, this could be analyzed mental damage from timber harvesting activities, and (2) external cost of timber harvesting operations which refers by using a system dynamic (sd) approach. this to cost of water treatment. ignoring the externalities approach is very comprehensive. it covers forest sector would lead to market failure or distortion in equilibrium aspects from timber up to paper consumption, which is price and quantity. in this context, government interthe main strength of this approach compared to other approaches in the econometric models with less scope vention is needed to alter the distortion of market equilibrium. but more detail. this is due to the timber prices used in the timber (3) in this study, the timber market analysis for sfm market does not reflect the price of environmental practices refers to the timber that were produced from resources. government could built-in the mechanism of natural forests. for the extension of this study, timber forest taxation rates which are in line with changes to produced from the forest plantation establishment is also needed to be taken into account in the analysis. this is market timber prices. in this context, majawat (2010) mentioned that there is a need to place monetary value to because forest plantations plays an important role in environmental services. supplying timber to the timber processing mills and ease the policy variables used in peninsular malaysia timber the pressure of natural forest which related to the timber market model (that is ha and ic) were significant and production. therefore, new timber market model for inelastic. exogenous shocks in those policy variables timber produced from forest plantation need to be developed. would have small impact on the equilibrium price and quantity of timber, and eventually impact on the economic (4) in the context of sfm, future research on integration welfare of timber industry. the result indicated that of all aspects related to sustainably managed forests stakeholders in timber industry experienced a small such as environment, economic and social is vital as the reduction in economic welfare due to sfm practices. result of the integration approach of these aspects would be more compatible. hence, future work needs to focus however, if the government could impose some good mechanisms, this could offset their losses. as a result, on developing sufficient approaches and methodologies this could encourage more stakeholders in the timber for better integration approach. industry to comply with sfm policy and minimized the (5) only the stakeholders in the timber industry for the externality effects from timber harvesting activities. this welfare economic impact analysis due to sfm practices could be materialized when timber producers include the were being evaluated in this study. hence, the gain and loss of the economic welfare is external cost of externalities in their total operational costs, or known as full economic costs. limited to the stakeholders in the timber industry. in fact, sfm practices affect other stakeholders (that is, society) as well apart from the stakeholders in the timber industry. future research direction in this respect, new research should be carried out in measuring the welfare economic impact of sfm practices based on this study, several elements of limitations are on other stakeholders that are believed to be related to captured. the potential future research directions are as the forests particularly on the ntfps and environmental follows: services. thus, the welfare economic impact of sfm practices (1) the extension of this study should be carried out in could be evaluated comprehensively and a better picture order to identify the total economic impact of sfm of the total gains or losses pertaining to the sfm practices to the rest of the economic sectors. in this practices could be drawn. 164 afr. j. environ. econ. manage. references abdul rahim as, mohd shahwahid ho (2009a). short run and long run effects of sustainable forest management practices on west malaysian log supply: an ardl approach. j. trop. for. 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(eds.) proceedings of the conference on forestry and forest products research (cffpr 2004) “forestry for society”, 6-8 october 2004, kuala lumpur malaysia. abdul-rahim et al. 165 appendix a. market equilibrium process domestic markets in order to obtain the equilibrium condition, we have to equate the supply and demand equations as can be seen in equation 6. as there is only domestic market in the peninsular malaysia timber market model, only domestic supply and domestic demand for timber were required to obtain the market equilibrium. then, we are able to calculate the equilibrium price. to find the equilibrium quantity, we can substitute the equilibrium price into either the supply or demand equation. equation a.1 was derived from the estimated result of equation 1 and 4. note that the value of 1 lnp and 0 were the summation of coefficient of price and intercept that have been estimated in equation 1 and 4 respectively. the rest of the coefficients correspond to the parameters in the model. 1 lnp = 0 2 lnah + 3 lnic +  4 lnipi +  5 lnwmp  6 lntst-1 + 7 lndd t-1 (a.1) in order to solve lnp, we have to divide the estimated coefficient in equation a.1 with  1 lnp =  0  2 lnah +  3 lnic +  4 lnipi +  5 lnwmp  6 lntst-1 +  7 lndd t-1 (a.2)  1 1 1 1 1 1 1 by substituting all of the parameters used in equation a.2 with the average data of time series, then we will be able to find the equilibrium price for peninsular malaysia’s timber market. to find the equilibrium quantity, we substitute the equilibrium price into either equation a.3 or a.4. lnts = 0 + 1 lnp 2 lnic + 3 lnah + 4 lnts t-1 (a.3) lndd = 0 1 lnp + 2 lnipi + 3 lnmp + 4 lndd t-1 (a.4) note that the calculated value of equilibrium price and quantity are in natural logarithm form. hence, we have to convert the equilibrium price and quantity to a real value. appendix b. welfare economic impact process using partial equilibrium consumer surplus (cs) and producer surplus (ps) concepts, it is possible to analyze the economic gains and losses in the domestic economy from the implementation of sfm practices. cs refers to the area above the equilibrium price line but below the demand curve (figure 3). it represents the difference between the amounts that consumers are willing to pay for a given quantity. ps refers to the area below the equilibrium price line but above the supply curve (figure 3). it represents the difference between the total revenue received by producers for producing a given quantity. it is typical for economist to measure cs and ps in order to assess the impacts on consumers and producers of given policies. in this study, we used integral calculus to find the areas of cs and ps that we adopted from hess (2002). from equation 6, we could further find cs and ps. to find cs we need to subtract the total expenditures of consumers (p0*q0) from the area under the demand curve up to the quantity transacted (figure 3). according to hess (2002), if the calculation is integrated with respect to the quantity variable, the marshallian formulation must be used. q 0 cs = area pp2b =  d 1 (q)dq  (p q ) (b.1) 0 0 0 alternatively, we could find cs by integrating with respect to the price variable. p2 cs = area fp2b = d (p)dp (b.2) p0 166 afr. j. environ. econ. manage. here the interval of interest is along the price axis from the equilibrium price p0 to the maximum demand price of p2. on the other hand, to find ps we need to subtract from the total revenues received, (p0*q0), the area under the supply curve up to the quantity transacted q0. ps = area fp0b = q0 (b.3) (p *q )  s 1 (q)dq 0 0  0 alternatively, we could find ps directly by integrating with respect to the price variable. p 0 ps = area fp0b = s(p)dp (b.4) f here the interval of interest is along the price axis from the minimum supply price of f up to the market equilibrium price of p0. african journal of environmental economics and management vol. 1 (1), pp. 001-012, august, 2013. available online at www.internationalscholarsjournals.org © international scholars journals review ecocentric and anthropocentric policies and crises in climate/environment, finance and economy: implications of the emerging green policy of the obama administration for africa’s sustainable development richard ingwe 1 *, joseph c. ebegbulem 2 and c. c. c. ikeji 3 1 centre for research and action on developing locales, regions and the environment (cradle), calabar, nigeria. 2 department of political science, university of calabar, calabar, nigeria. 3 institute of public policy and administration (ippa), university of calabar, calabar, nigeria. accepted 6 april, 2013 advanced economies responded to recent global financial meltdown and economic recession by implementing “green” economic stimulus packages concentrating on environmentally-friendly and sustainable technologies. we examined this emerging paradigm against sub-saharan africa’s underdevelopment (prolonged poverty, economic stagnation/decline, weak structures, processes, institutions and attitudes required for accelerating economic growth; practice of electoralism: power derivation through elections without democratic ingredients), exclusion of stakeholders including civil society from policy, thereby depriving society innovations and resources contributed by civil society elsewhere to socio-economic development. we used desk research and descriptive methods to analyze secondary data based on increasing civil society involvement in development processes under emerging paradigm of partnership, governance, climate change, global financial crisis. we showed that past actions: unbridled pursuit of anthropocentric policy that ignored ecocentric measures led to crises (environmental-climate degradation, and recently global financial meltdown and economic recession), thereby worsening existing challenges. we recommend that african nations adopt the emerging green policy thereby increasing their chances of benefiting from the assistance of governments. the promotion of green development policy in africa is of urgent need and imperative. key words: “green” development policy, africa, anthropocentrism, ecocentrism, climate change, economic growth. introduction the us presidential campaign that started in 2006 and ended with a landslide victory by barack h. obama featured a strong commitment of the victorious president obama on “change”. a few days after inauguration, it was reported that president obama has taken various steps towards realizing the change he promised. the previous us government denial of climate change science was promptly reversed by president obama. in his speeches for presidential campaign and acceptance of nomination as us democratic party’s presidential candidate, presi *corresponding author. e-mail: ingwe.richard@gmail.com, cradle.africa@gmail.com. tel: (+234) 8051740656. dent obama has repeatedly stated his belief that green development (including renewable and efficient energy technologies and other environmentally friendly systems) promise and deserve to be employed as a us government strategy to surmount (and recover from) the recent global financial meltdown and economic recession (obama, 2009). specifically, green development strategy is being considered as a means of sustaining current jobs and creating new jobs with several advanced nations of the north entrapped in the global financial crisis, subsaharan africa is likely to face a greater burden of the rather increasing wave of global challenges. unlike most parts of the world including north america, western europe, japan or the north, and south east asia, subsaharan africa has not gained from centuries of the glo ingwe et al. 002 balization process. industrial revolution, liberalization of trade, capital markets, among other mechanisms have tended to work in ways that subsaharan africa remains under socio-economic stagnation or decline (khor, 2001). this might be the case with the current degradation of the environment. prior to the recent global financial meltdown, subsaharan africa had become nearly synonymous with poverty, conflict and wars, among other indicators of underdevelopment or the perpetuation of the replication of poverty and economic stagnation and/or decline. development aid/assistance promised by advanced (economically and industrially) countries were, by and large, not fulfilled. at the global level, the pursuit of unbridled economic growth development strategy and downplaying of ecological (non-human) nature protection despite mounting scientific evidence that global warming had progressed to a highpoint that climate change was becoming abrupt, dangerously compelled the former un scribe; kofi annan to state that the world lacked leadership in the environmental (climate) sector. the disproportionately large percentage of poor people in sub-saharan africa compared to other parts of the world is well documented (undp, unep, world bank and wri, 2005) is elaborated under the description of the study area below. disasters, hazards and risks have been most frequent in the region. these range from huge losses of lives and property due to abysmally low levels of services (safe water and sanitation, healthcare, education and so forth (undp, unep, world bank and wri, 2005). terrorists struck nairobi, (kenya) and elsewhere in sub-saharan africa before the september 11, 2001 attack on the world trade centre and the pentagon in usa. there have been increasing reports that the recent global financial meltdown has taken a toll on the economies of the region: most recently the financial and money markets of nigeria have been very badly hit by unprecedented recession (newsweek, 2009). the predictions of impacts of climate change and global warming have put sub-saharan africa on top of the list of the most vulnerable regions. the huge migration of people predicted to be forthcoming (brown, 2008; stern, 2006) would add to past, present or ongoing migrations due to frequent wars and strife. despite a series of mounting scientific evidence that global climate change was inflicting irreversible transformation on the earth’s environmental and climate subsystems, govern-ments especially in the industrialized and economically advanced nations almost obstinately continued to pursue economic growth-centered development strategy while ignoring the deleterious consequences of that attitude on the global ecosystem especially the life bearing biosphere. the market (capitalist) system’s promotion of laisses faire or unfettered freedom to pursue profit and wealth led to an increase in temperature of the global environmental system of 0.6  0.2°c in the twentieth century. this has been attributed to the continued and increasing emission of greenhouse gases (ghg) which is in turn triggered by increasing release of carbon dioxide (co 2) gas arising from the burning of fossil fuel and landuse change (wri, 2006; ipcc, 2007, 2001; byrne et al., 2008: 27). research derived predictions of climate change impacts have stated various deleterious disasters for different parts of the world. sub-saharan african countries have been predicted to be the one of the parts of the world that will be most vulnerable to climate change impacts or disastrous events (stern, 2006; myers, 2006) . it is widely accepted that climate change is the greatest challenge facing mankind currently (ki-moon, 2007). background to the problem the significance of think-tanks and civil society to policy making: policy making by governments of advanced nations (especially the usa and uk) since the 1960s and later emulated in the uk have been facilitated by thinktanks – describing policy research institutions of two types as follows: i) non-government, non-partisan organizations that facilitate strategic coordination of government policies or enhance the relative prioritization of policies, creates new policy alternatives and/or clarifies policy options as well as their implications. for example, the policy studies institute and the central policy review staff (cprs) while the labour government undertook profuse and profound constitutional reform of 1997 under a think-tank: established in 1995: the constitution unit; ii) partisan organizations (frequently affiliated to and funded by political parties) providing policy advice to selected clients. in the us where this kind (like the first) originated, the urban institute and the brookings institute have served the democrats while the heritage foundation and the american enterprise institute have served the republicans. some of the think-tanks that served the uk are: the centre for policy studies (for the conservatives) and the institute for public policy research (for the labour party) (bradbury, 2003 in mclean and mcmillan, 2003). the inability of countries of the south (that is developing nations including sub-saharan africa) to benefit from globalization has been attributed to the ignorance of these nations of the contributions that think-tanks make to the enhancement of economic growth policies (khor, 2001). therefore, it has been suggested that south-south policy coordination among developing countries is required as a way of reversing the way the gains of globalization have been engineered and reaped by countries of the north. to achieve this goal, south-south cooperation has been proposed to be informed or supported policy-wise by centres engaged in research and coordination of economic growth and development including such organi 003 afr. j. environ. econ. manage. zations that are independent and privately run. their functions have been proposed to include: supporting countries of the south to prepare for international negotiations, and organize and undertake strategic thinking and long term planning of economic growth and development (khor, 2001). what is sub-saharan africa doing to respond to the “change” being implemented by president barrack obama and peers? the fact that globalization process, which set off about two to three centuries ago and is ongoing, has integrated the economies of most sovereign nations and regions was recently confirmed by the rapid diffusion of the financial meltdown from the usa to europe, asia and africa. while president obama is rapidly responding to the economic crisis or recession by employing green development strategy including sustainable energy, the corresponding change in development and other policies by sub-saharan africa collectively and individually is yet to be well known and or publicized. study area: africa and sub-saharan africa geographical, social and economic setting the entire african continent comprising about 55 countries is usually located at the centre of conventional world maps. the total population estimates and projections by reliable international organizations for sub-saharan africa ( comprising 50 nations in 2005) was 732,512,000 people (that is 11.4% of the world’s population) and expected to be 1,181,279,000 people by 2030 (that is 14.5% of the world population) . sub-saharan africa is widely regarded as the region of the world presenting the poorest social, economic and environmental conditions. the region’s gross domestic product (gdp) in 2002 was us$393,001 million (that is only 1.1% of the world’s total (us$35,065,010 million) in 2002. the region’s gdp per capita ppp was $1,779 compared to the world average of $7,880 in 2002. the poverty level in the region was comparatively serious when the gdp per capita of other regions is considered as follows: $35,138 for north america; $21,348 for oceania; $18,097 for europe; $5,934 for middle east and north africa; $4,684 for asia (excluding middle east); $7,347 for central america and caribbean; and $7,339 for south america. the proportion of the population living on less than $1/day and $2/day (based on surveys in 1987 – 2001) were 46.5 and 78.0% respectively compared to 2.4 and 29.9% in the middle east and north africa (undp, unep, world bank & wri, 2005). food insecurity was high and prevalent in the region: labour (that is workers) per hectare of land in the region (1.02) compared to other regions (0.87 for the world); received the largest quantity of cereals as food aid (3,145,000 metric tonnes) compared to other regions in 2002. unemployment rates are likely to be the highest in the world in the region due to a combination of reasons including the low absorptive capacities of national economies, poor governance, prevalent injustice, poor employment information and management (including reporting) systems. although most sub-saharan african nations did not report unemployment rates for 2000 – 2002, the only three that did presented some of the highest rates worldwide; the unemployment rates of 29.5 in the region’s largest economy (south africa) and 33.8 for (namibia) were only equaled by macedonia, fyr (31.9) and algeria (one of the most prosperous north african nations) with 29.8. nowhere or no country elsewhere presented such alarming levels of unemployment in the world. (undp, unep, world bank and wri, 2005) the world bank’s classification in the early 2000s the region presents a disproportionately large percentage of the member -states of the rather unfortunate categories of nations classified as “low income” “least developed countries” (ldcs), “highly indebted poor countries” (hipc) but only a few to the “middle income” category and none is in the “high income” class (undp, unep, world bank and wri, 2005: 174 – 227). economic (growth) performance in africa has risen between 1995 and 2004: economic growth (indicated by purchasing power increment) was 5.8% compared to 4% in 2003 (geo data portal from world bank 2006). however, to meet the millennium development goals (mdgs), subsaharan african economies are expected to grow at the rate of seven percent so that poverty can be reduced by half by 2015 (adb, 2004). climate change, water availability and other environmental and socioeconomic challenges (currently and expected) have been observed to affect several parts of the region [west, central, north, east (most severe/prevalent) & southern africa]. these are described in detail in the literature (e.g. mafuta et al. in unep, 2007). climate and environmental challenges facing africa about five million square kilometers of land in africa was adversely affected by degradative forces in 1990 thereby causing loss of livelihoods and worsening existing poverty. serious and prevalent poverty in africa compels people to disregard sustainable management of land and resources on it when they are pursuing immediate survival and satisfaction of basic needs for food, shelter and clothing. this situation caused greater and more devastating land degradation. poverty and application of rudimentary agricultural techniques perpetuates poverty ingwe et al. 004 and land degradation under a vicious cycle of poverty. since 1981, food production per capita on the continent declined by as much as 12% (undp, unep, world bank and wri, 2005). although sub-saharan africa’s contribution to global ghg emissions were the lowest in the world (0.7 billion metric tonnes of co2 for 1990 – 2004), (un, 2007), climate change (extreme weather events: drought, flooding) have been reported to exert pressure on and exacerbate land degradation on the region. it is adversely affecting the region’s hydrography (changing river catchment), fuelling deforestation and desertification and reducing the quality of services offered by the ecosystem. responses to these challenges have included the policy of promoting integrated crop and land management programmes designed to also improve agricultural productivity. two major factors have been advanced to explain the dismal performance of policy in this regard: deficiency in the policy framework, and an unjust system agricultural subsidy practiced in advanced nations (mafuta et al., 2007: 195 – 197 in unep 2007). the article argues at the outset that the failure of subsaharan africa to rapidly and decisively respond to the opportunities being perceived by the obama administration in regard to green development/technologies represents an agreement by leaders (political) of the region to perpetuate poverty and underdevelopment, unemployment, among other maladies in the region. the problem despite the deployment of partnership and participatory development strategies in advanced countries of the north especially the usa and uk, developing countries including subsaharan africa are yet to realize the significance of policy-relevant civil society organizations or think-tanks in the making of evidence-based policy for achieving sustainable development. policy and decision making in sub-saharan africa seems to be restricted to the ideas, whims and caprices of the political or power elite. therefore, civil society in sub-saharan africa has, by and large, been excluded from the policy process. this has led to a situation whereby the benefits accruing from the creativity, versatility, flexibility of civil society’s approach to tackling most of the global challenges (climate change, poverty, violence, terrorism) to be forfeited by poor african countries. the consequence of this social exclusion, elitism is the perpetuation of poverty and underdevelopment, inequality, among other ills of the society, economy and environment. although john byrne and colleagues have solicited for “civil action to shrink the (increasing global) carbon footprint” as a means of “undoing atmospheric harm” resulting in dangerous and abrupt climate change, these have been directed at the us government and other western countries (byrne et al., 2008). calls for policy shifts from anthropocentrism towards ecocentrism in africa have been rather scanty and improperly directed. questions what recent political changes in the usa towards green development strategies provide prompts for (re)alignment of development directions in sub-saharan africa that promise to benefit the region? what success stories in green development in developing nations of the south promise to make this strategy profitable for sub-saharan africa? to what extent does a pan african civil society-led green development strategy promise to accelerate sustainable development in sub-saharan africa? the purpose of this article is to raise this development issue, the gap in the policy response among nations and regional economic and political blocs to the visibility of the global and regional development community. objectives 1. to show how various philosophical perspective (ecocentrism and anthropocentrism) have resulted in deleterious outcomes for both human kind and nature in form of climate change and global financial crisis and economic recession. 2. to highlight the need for increased support for and consideration of the contributions of think-tanks to africa’s sustainable development at regional (that is continental), and national policy levels. 3. to show how recent changes in approaches to socioeconomic and environmental management in the usa and elsewhere towards green development agenda not only provide an example for sub-saharan africa but also offer opportunities (better than hitherto) for the african region. 4. to show a pan-(sub-saharan) african strategy led by civil society promises to complement public sector policy that is capable of leveraging the rate of development. organization of this article this article is organized in sections: having used the first section to introduce the title and relevant preliminaries, the second section will present a theoretical-conceptual framework for guiding the discussion. two major concepts: ecocentrism and anthropocentrism are presented as key philosophical perspectives that describe the policy disposition or foundations of governments at national, sub-national and sometimes regional or international levels. the consequences of the foregoing policy perspectives on humankind and nature are presented in form of climate change and the global financial crisis. the third section shows how various approaches to national development policy (that is tendencies towards either ecocentrism or anthropocentrism, or both) have been 005 afr. j. environ. econ. manage. exhibited in the different recent political regimes in the usa especially during the administrations of williams (bill) j. clinton, george w. bush and the incumbent barack h. obama. in the fourth section, we argue that the rather dismal performance of policy globally and nationally has been amply indicated by climate change (which represents the failure of the goals of the ecocentrists) and the global financial crisis (indicating that the best offered by anthropocentric community failed to prove enough and costeffective) – for sustainable development. following this outcome, we conclude that the green policy being charted by the obama administration promises to resolve the multiple crises by addressing ecological, economic and social concerns/problems. however, we recommend the need for the global community to follow the serious promises of president obama that the us government will not only acknowledge climate change but lead in tackling the debacle. on this point, we recommend the resort to the first and clear warnings and recommendations of climate scientists from think-tanks at international and national levels regarding the targets for ghg emission reductions instead of the rather politically and anthropocentric agreements that have so far been reached especially involving eu concessions to canada, australia, japan and russia in the july, 2001 international meeting in bonn (germany). we conclude that think-tanks be supported to guide ecocentric policy at global, national and sub-national levels as a way of avoiding the widespread catastrophic consequences predicted to occur, should humankind perpetuate past and current lifestyles, especially the over-use of hydrocarbonbased fuels (fossil and nuclear energy sources). conceptual framework and literature review: ecocentrism vs. anthropocentrism some strands of political philosophy have developed suitable concepts for analyzing various policy choices of governments and/or administrations. for example, political philosophers among others have developed and used the concept of ecocentrism to refer to a nature-centred system of values for embedding public policy. ecocentrists justify their values for emphasizing nature protection, preservation and conservation on an ontological belief and consequently ethical claim. they debunk two claims promoted by anthropocentrists that: i) human beings are superior to non-humans and therefore constitute the sole bearers of intrinsic value in the ecological system within which man is only a part. ii) humans and human nature are in possession of a greater intrinsic value compared to their non-human counterparts and their own nature. therefore, ecocentrists advocate for the enthronement and/or practice of biospherical egalitarianism, a philosophy that promotes equality of the intrinsic value for both components or natures of the ecosystem: human and non-human. ecocen-trists have constituted a radical rejection of the human-centred development policy and practices called anthropocentrism, which is relatively older and more deeply entrenched in public policy systems, and attitudes of industrialized western culture including the scientific community. this paradigm of (anthropocentrism) hinges its value system in determining the need for protecting non-human nature on the extent to which the demands of human utility have been satisfied. in this regard, human welfare is the basis on which the greatest premium is placed as the primary challenge or interest of policy while nonhuman nature (and its conservation) is considered to be secondary. anthropocentrists and critics of ecocentrism claim that the placement of high premium on non-human nature protection is unnecessary, represents the promotion of an anti-humanist morality through which human well-being is ignored, downplayed in favour of the empty claim and poorly defined claim that non-human nature protection leads to the achievement of the “greater good” (humphrey, 2003 in mclean and mcmillan, 2003). the prolonged practice of human welfare-centred public policy generally in the usa and the western culture could be inferred to be a commitment to unbridled anthropocentrism. while the deliberate denial of climate science especially the several warnings about an increasingly warming globe (or global warming) represents an extreme form of political interest promotion, an issue beyond the scope of this paper. however, it deserves mention that it has taken centuries (the 19 th century) since arhenius published one of the pioneering reports about the warming of the earth (arhenius, 1896). this prolonged reluctance to consider the ecological consequences of anthropocentric and strictly economic growth-centred development policy generally and the associated attitude promoting public energy systems to over-rely on fossil fuel (petroleum oil, natural gas, coal among others) has led to the dangerous and abrupt climate change problem. there is an emergent and increasing advocacy for a rapid transition in public policy on energy to shift “from fossil fuels to renewable energy” (droege, 2008: 1 – 14) and energy efficiency systems (alliance to save energy, ase. 2007, 2008). this advocacy has been well documented and needs not detail us here. we turn to a brief elaboration of ecology and its relevance and application in government and public policy because of the enormity of the climate change challenge to the global and african environment, society and economy, and polity. ecology, green philosophy, politics/ government and sustainable development in sub-saharan africa the work of lincoln allison shows that the term “ecology” ingwe et al. 006 was originally used in its german form: “oekologie” to refer to “the science of relations between (living) organisms and their environment” (haeckel, 1866). this definition is believed to have remained useful since its formulation. the following three dimensions of the concept (ecology) have been distinguished: i) an academic and professional field concerned with studying and explaining the system of interactions among living organisms. ii) the study of the system of actual causal interrelationships among species of fauna and flora. iii) the way the existence and significance of a distinct ecological system is perceived, considered and incorporated into programmes of politics and morality of the society. in this sense, the emphasis on morality and politics deviates from the earlier conceptions of the subject thereby making this subfield or definition to fail to satisfy the views of some professional ecologists (that is, those who define and practice the discipline differently). moral and political ecologists question and reject the viability of the way most programmes are planned and implemented in ways that disregard the need to sustain the harmony between humankind and nature thereby allowing and causing non-human nature to suffer enormous degradation and destruction. therefore, political ecology emerged as a subfield concerned with: promoting efforts to achieve the above objectives; enhancing the coherence of the pursuit of morality and politics in development planning and management and ensuring that the relationship between scientific ecology and political-moral ecology is sustained and maintained. the emergence of increased environmental consciousness in the western world in the late 1960s and early 1970s led to the distinction between the political aspect of ecology and the scientific leanings of the subject. the implications of the idea of ecology also gained the interest of moral philosophers including arne naess, a norwegian who formulated the concept of “deep ecology” as a subfield that is devoid of “anthropocentrism”, which was perceived to be “shallow ecology” but concerned with promoting the principles of “biospherical egalitarianism”, “diversity and symbiosis” and “decentralization”. the shallowness of ecology practiced and advocated by anthropocentric environmentalism described the way its practitioners myopically concentrated on the conservation of fossil fuels and beautification schemes which were undertaken with the sole purposes of promoting human welfare or consumption of natural resources. moreover, proponents of “deep ecology” argued that the shift to their camp was necessary because achievement of its goals/objectives translated into the achievement of the objectives of shallow ecology. the creation of “green philosophy” resulted from this debate combined with increasing consciousness and consideration of ecological issues since the 1970s. allison claims that ecological political theory, a compo nent of the wider “green philosophy” presents a fundamental problem: neither a model of ecological stability nor a proposal or idea of a universally accepted role that humans should play within the ecological system has been provided. instead, ecological political theorists have resorted to the creation of the darwinian model of an unstable and evolving system based on the scientific ideas espoused by charles darwin (1809 – 1882). darwinists argue that humankind, (although other constituents of the ecosystem play their roles) is principally instrumental to the modification of life conditions of other species, thereby determining the living chances of all species either for the worse and more for the better. for example, john halliday suggested that darwinism concentrates on populations of no fixed or predetermined boundaries, contrasted to biologists’ concern with species types which individually possess fixed essence and form. survival of populations under darwinists’ conception depends on “natural selection” of favourable and heritable variants of populations (organisms) which better adapt to their environment or niche. unremitting pressure of the selection process causes organisms that fail to adapt to the environment to get rejected through either death or sterility (halliday in mclean and mclillan, 2003). lincoln allison suggested that collective and individual choices (the pursuit of improved living standards by man) are ecologically neutral: that is, can neither be said to be wrong or right per se! however, there has been increasing but incoherent advocacy for the consideration of rigorous analysis of the ecological consequences of human decisions and also the ecological or environmental aspects of policy (allison in mclean and mclillan, 2003: 161 – 162). the looseness in the advocacy for ecological considerations in policy has tended to be associated with the disposition of policy makers especially the us governments prior to the obama administration. therefore, we turn towards elaborating the concept of climate change and its recent acknowledgement by us president barack obama. climate change and global lack of leadership in the climate-environmental sector increasing emission of green house gases (ghg) comprising carbon dioxide (co2), methane (ch 4) among others over the years has led to the “ceiling” of the atomsphere thereby causing solar radiation entering the earth surface to get entrapped between the earth surface and the atmosphere (that is, below the “ceiling”) instead of getting reflected back upwards beyond the atmosphere. this phenomenon which is abnormal due to its contradiction of the condition of the global atmosphere prior to the formation of the atmospheric “ceiling” due to ghg concentration because of the steady and rapid increase in temperature of the global atmosphere since its 007 afr. j. environ. econ. manage. emergence is called “green house effect”, global warming and/or climate change. the phenomenon has been prolonged, caused changes in the mixture of gases constituting the earth’s atmosphere over the years and centuries and led to fluctuations in the average global temperatures all through its emergence. it has been characterized by the following: 1. created by the action/consumption habit of humankind especially over-use and over-reliance on fossil fuels and land-use change. 2. an unprecedented rate of occurrence. the consequences of climate change have been reported to range from uncertainty of models predicting increased deforestation, desertification, pole-ward shift of vegetation and animal populations, rising sea levels, decreased precipitation (humphrey, 2003 in mclean and mclillan 2003: 225). more recently, use of improved equipment and approaches in scientific studies undertaken by the intergovernmental panel on climate change (ipcc) led to projections that the continued build up of ghg emissions from human activity, especially in the 20 th century (during which temperatures rose between 0.6  0.2 o c), would lead to an increase in 200 average global temperatures between two and 4.5 o c by the year 2100 compared to 1900 levels (ipcc, 2007, 2001). this disastrous situation can only be avoided through prompt actions designed to promptly reduce the accumulation of atmospheric ghg. various researchers have shown that high end warming (or accumulation of ghg) of the range presented by the ipcc and colleagues would lead to widespread catastrophic consequences (schneider and lane, 2006, stern 2006, myers 2006). to avoid the widespread catastrophic consequences projected, some preventive and protective conservation measures have been proposed. one of the most popular of these proposals has pegged the threshold for carbon concentrations at no more than 450 parts per million (ppm) (oppenheimer and petsonk, 2005; hansen, 2004; parry et al., 2001). actions for curbing the carbon footprint owing to the recent agreement of the global scientific community that anthropocentric attitude (especially over use of fossil fuels) have triggered the change in climate, advocacy for prompt and considerable policy responses designed to avoid the predicted future catastrophic consequences have increased in intensity and frequency. one of the policy responses include the “stern review on the economics of climate change” which was prepared by sir nicholas stern, a former world bank executive, for the office of the prime minister and the chancellor of the exchequer of the united kingdom. the stern review recommended the necessity for all countries to reduce by 80% or higher the level of anthropocentric emissions (stern, 2006). national academies of sciences of the g8 nations (comprising the usa, uk, japan and others) and those of developing nations (india, brazil, and china) jointly issued a statement advocating for urgent, significant and prompt actions designed to respond to the climate debacle in june 2005 (the royal society, 2005) in byrne et al. 2008. political attention to global warming: the kyoto protocol mathew humphrey suggests that about 36 years ago, climate change started receiving increasing political attention due to the way it has become the crux of the emergent green politics of the period. a key milestone of global political response to climate change is the intergovernmental meeting of representatives of national governments and organizations in the japanese city, kyoto in 1997, during which the endorsement of a proposal by 38 industrialized nations led to the emergence of the kyoto protocol. under the kyoto protocol, the 38 industrialized nations (annex 1 countries) committed to reducing their co2 emissions at an average of 5.2 percent from 1990 levels by 2012. this measure was by far lower than the target of 60% reduction that climate scientists recommended as necessary for avoiding the widespread catastrophic consequences of climate change resulting from further global warming. however, the protocol represented a consolation to activists of green politics/development that adjudged it as a good and initial agreement that forms a basis for further work. it was heartwarming to environmental-climate campaigners in 2005 (february) when the protocol came into force through the achievement of the 55% endorsement by the signatory nations (ngls, 2005). variable approaches to national development policy rejection of the kyoto protocol by the us government led by george w. bush since its inception, series of intergovernmental meetings have been organized to mobilize greater political and legal forces, authority and power to transform the protocol into an enforceable treaty. in the first of these meetings held in november 2000 in the hague, the insistence of the usa that forests and vegetation must be counted as ‘carbon sinks’ thereby providing a favourable standard for enormous fossil fuel consumption and associated co2 emission could be offset, caused major disagreement from the european union (eu). the eu feared that this us proposal would constitute a loophole in the agreement due to the uncertainty, temporariness and instability of the carbon storage capacity of vegetation. the protocol suffered a major setback due to the unilateral withdrawal of the us government from the agreement following the election of george w. bush citing the chances of inflicting disproportionate damage on the economy of the us if adopted. the setback posed ingwe et al. 008 by the us led to the protocol arises from the fact that the us contributes one of the most enormous co2 emissions (24% of the global total) . therefore abdicating its responsibility to commit to the binding agreement represents a major obstacle in the quest for equity and justice in global and national response to the climate crisis. other negotiations of response mechanisms founded on the protocol have included: the recent global meeting held in: the indonesian city of bali in the fourth quarter of 2008; in bonn (germany) in july, 2001 – where 186 national representatives conferred and successfully upgraded the protocol into an international treaty. this success was realized through the european union’s (eu) concession to canada, australia, japan, and russia in form of: the magnate de of allowances granted to nations interested in using forest as “carbon sinks” and also the type of mechanisms that could be applied to enforce the agreement. the bali meeting successfully produced a road map for further negotiations. the eu concession to the four nations effectively lowered the size of emission reductions from earlier proposal of 5.2% in 1990 levels to between 1.8 and 3% (humphrey in mclean and mclillan, 2003). why green development has been attractive to governments in europe and elsewhere: their climate-environmental friendliness several reasons that have compelled governments in the european union and elsewhere to adopt green development policy includes the emergence of climate change, crisis in the energy sector of nations that have been using over -centralized national grids for supplying electricity and socialeconomic problems such as unemployment, collapse of centralized grids. therefore, the adoption of sustainable (renewable energy and energy efficiency) systems of powering economic, and social systems have become popular because of their environmental benignity, and also the experience that by their decentralized nature (that is, implementation in sub-national regional scales: states/provinces, local governments, towns and municipalities), they create new and more jobs than conventional energy stems (large hydro, nuclear power stations, coal-fired stations). these factors have led to rapid adoption of green energy policy in several nations of the world such as germany, denmark, india, brazil (droege, 2008). the immense benefits arising from green power has encouraged the rapid growth of implementation of various types of renewable energy and energy efficiency systems around the world. since 2000, the installed wind energy capacity from wind turbines for generating electricity more than quadrupled. output rose from 17,400mw to 74,220mw in 2006. while the order of global leadership in descending order in the wind energy capacity in 2006 was germany (28%), share), spain, usa and india (www.dbresearch.com, 25 o in africa: 22 – 3), the usa recently rose to global leadership in wind energy implementation. moreover, renewable energy sources are credited with specific avoidance of co2 or “carbon (emission) costs” in the following order (in tonnes): photovoltaic (pv) (500 – 600), wind (60 – 70), hydro (unspecified) (35 – 55), carbon separation (28 – 53), new coalfired power plants (14 -26) (euracoal cited in 25 o in africa, 2008: 23). the risk of climate change impacts on africa on november 15, 2006, at the 12 conference of parties to the un framework convention on climate change (unfccc) in nairobi (kenya), the un secretary-general: kofi annan said, “the impact of climate change will fall disproportionately on the world’s poorest coun-tries, many of them here in africa. poor people already live on the front lines of pollution, disaster, and the degra-dation of resources and land. for them, adaptation is a matter of sheer survival (annan /united nations 2006). the devastation wrought on africa by climate change expressed by (extreme weather events: drought, flood, increased temperature) have increasingly been documented in the literature. for example, the occurrence of flood in mozambique, food insecurity in ethiopia, diseases, for example, malaria in southern africa and drought in malawi and agriculture and food security have been reported (hellmuth, 2007). however, these reports seem to pertain only to the harbingers of climate change and do not cover the deleterious or more serious climate change impacts that will occur if policy ignores the warnings and recommendations for action by climate scientists. more devastating impacts might occur in future as indicated by past and current climate events. these beckon for the creation and use of research – derived information for policy and decision making. the official african union (au), (formerly organization of african union, oau) sources claim that some responses of the continental political-economic body to climate change have occurred. these include: the establishment of the new partnership for african development (nepad)’s environment initiative, which is supported by the au and the creation of a related action plan: all of which acknowledge the problem of climate change and variability and by implication the urgent need to address them. moreover, the recognition of the need to coordinate proactive programmes designed to prevent and respond to disasters and risks was demonstrated through the creation of the auc – supported nepad africa regional strategy for disaster risk reduction. it was proposed that the un economic commission for africa and the african development bank (afdb) would collaborate with the un to support the gcos – africa climate (change) for development – a new programme that was scheduled to also respond to climate change 009 afr. j. environ. econ. manage. and development issues from 2007. this programme has the objective of mainstreaming climate information into national development plans and programmes by initially concentrating on those sectors of national economies that are most sensitive to climate. the programme is also a component of the global climate observing system (gcos) designed to combine climate information and services with development plans as means of promoting the achievement of the millennium development goals (mdgs) babagana in: hellmuth et al. 2007. the foregoing responses to climate change and variability are restricted to continental institutional framework revolving around the au. the mitigation and adaptation to climate change and variability would not be cost-effective if pursued based solely on those mechanisms. it has long become the mantra that local action and solutions are appropriate responses to global issues and problems such as climate change. therefore, national institutions, structures, processes and attitudes for responding to climate change are as important as their subnational counterparts. so are those at the regional levels such as ecowas for economic community of west african states, south african development community (sadc) and so forth. sadly, responses to climate change at levels smaller than the african continental region seem to be poor if not virtually inexistent. the poor response of african universities to crisis in finance and economy climate change as indicator of weakness of policy the raising of climate change to global and national visibility of policy makers was achieved through the meritorious work of research derived information provided by universities, think-tanks, non-government and civil society organizations (ngos and csos). some of these organizations include: the intergovernmental panel on climate change (ipcc), the royal society (uk), centre for energy and environmental policy (usa), world council for renewable energy (wcre) (germany), world wind energy association, wwea (bonn, germany), among others. in africa, think -tanks of this nature are few. this poses a problem for the generation of information and knowledge as well as implementation of programmes concerning the mainstreaming of multi-sectoral programmes into national development programmes at national and regional levels (e.g. ecowas, sadc, and so forth) as obtains in the european union and elsewhere. moreover, recent research indicates that the response of national university systems in some african countries to climate change has been rather poor. for example, despite the emergence of over 100 universities in subsaharan africa’s second largest economy (nigeria), the offer of specialized courses for awarding degrees and diplomas and specific course streams dedicated or devo ted to climate change and variability issues, public enlightenment and awareness raising concerning climate change, among other academic and professional programmes are yet to be seriously undertaken by nigerian universities as obtains elsewhere in the world especially in north america and europe (ingwe, 2009). information on the au response to crisis in finance and economy was not available to the authors at the time of this research. poor response of national governments in africa to climate change, financial and economic crisis in context of poor systems of economic management, education, science, technology, and environment, the response of most governments of nation states to the crisis in climate, finance and economy to be compromised or ineffective. this situation is attributable to the underlying weaknesses in national university systems, poor funding systems and the virtual absence of thinktanks that specialized in generating research-derived information on the affected sectors (khor, 2001). the foregoing crisis portends impediments in the quest to achieve the mdgs, which before the global financial meltdown and economic recession were feared to be unachievable. the un report of the mdgs in 2007 revealed several bleak results. sub-saharan africa presented the worst levels (that is, did not show that the mdgs would be achieved by 2015). for example, it remained the poorest region with 41.1% off people living on less than us$1/day in 2004; poverty gap ratio was 17.5% in 2004 (the highest worldwide); 166 children under five years old died per 1000 live births in 2005 (the highest worldwide); only 26% of the land area were covered by forests in 2005 – indicating compromise in ensuring environmental sustainability. the region presents the highest proportion of slum dwellers (62% of the total population) in 2005. this implies the low level of access to electricity and energy worldwide. the proposed implementation of a global partnership for development was rather poor before the global financial meltdown and economic recession. there was little to show for donors’ pledge to double their aid to africa at the millennium declaration in 2000. the official development assistance from developed countries as a proportion of donors’ gross national income (gni), between 1990 – 2006 declined from 0.35% in 1992 to about 0.25% in 1997, about 0.27% in 2004 before rising to about 0.35% in 2006. access to markets was contrived to be preferential and favour developed countries (united nations, 2007). the global financial crisis (gfc) this economic phenomenon started in september 2008 and has persisted till today (march, 2009), and has been characterized by failure, of merger, or conservatorship of numerous large financial firms in usa. later it spread to ingwe et al. 010 the insolvency of other companies, most governments in europe, economic recession, and declining stock market prices around the world. before its manifestation, the likelihood of its occurrence had been reported by journals of business, which drew attention to the (in)stability of the major investment banks in the usa and europe as well as insurance companies. mortgage banks, which had shown signs of the occurrence of the mortgage crisis that was experienced during the crisis had been marked by: credit crisis, bank failures, and reduction in stock market indexes in europe and also largescale lowering of the value of equities and commodities. it has been reported that the section 128 of the emergency economic stabilization act of 2008 has worsened the situation through its allowance of the us federal reserve to reward reserve requirement balances held on deposit from banks through the payment of interest, removal of incentive for banks to give credit to rather than providing cash on deposit with the federal reserve, liquidity crisis ensued due to the de-leveraging of financial institutions and also the declining international trade. the crisis is continuing irrespective of the efforts of national ministers of finance, governors of national apex (central) banks to work in a coordinated manner to address this frightening phenomenon. moreover, it is changing its manifestation including the currency crisis which occurred in october 2008 in form of transfers of huge capital resources by investors in the stronger currencies (such as the chinese yen, the us dollars, swiss franc) and has caused several economies to search for or solicit aid from the imf (http://en.wikipedia.org/wiki/global_financial_financial_cr isi_of_2008). the response has included us government takeover of home mortgage lenders. major features included filing for bankruptcy by lehman brothers following the refusal of the federal reserve bank to offer support, the sale of merrill lynch to bank of america; all on 14 september, 2008 (http;//en.wikipedia.org/…). the “eu pledges fresh 75bn to fight crisis” was an addition to previous provision of other support to the imf (international monetary fund) (the punch, 2009: 21). emerging green development policy of the usa under the obama administration and china while renowned experts in climate change response such as joseph stiglitz and nicholas stern are still calling on president obama to take leadership of the global green recovery from the crises of climate change and the financial and economic recessions (stiglitz and stern, 2009), some have already credited the us president of being on the lead already (robbins et al., 2009). the financial bailout proposed by president barrack obama initially was $1.5trillion, and there was a compromise between the us senate$838bn and the us federal legislature $819bn – versions approved early february, 2009 receding us economy (by a 61-37 vote) to restore the……....(http://news.xinhuanet.com/english/2009-02/10/ content_10797232.htm) apart from the proposal that a substantial part of the bailout will be invested in developing and implementing sustainable (renewable and efficient) energy technologies and systems as a means of creating most of the three to four million jobs promised by the obama administration, president obama had acknowledged the manifestation of climate change as a global threat during his…month campaign and during and after his inauguration in and since january, 2009. he has further committed the us government to leading the global effort to mitigate and adapt to climate change. these actions and positions of the us government constitute an emerging green development policy promises a departure from previous global lack of leadership in the environmental sector. president obama has already issued several directives to us government departments and agencies showing how programmes should be formulated and implemented to use green development strategies to achieve sustainable development. china joins the green development philosophy recently, analysts have declared that “the colour of stimulus goes green” (robbins et al 2009). robbins et al. (2009) reveal that governments across the globe have allocated over usd43billion in fiscal stimulus focusing on key climate change reduction investment themes with china and the usa in the lead worldwide. they believe that this represents the beginning of a future green economy that is, carbon reduction economic growth strategy. the g20 recovery talks and the copenhagen climate negotiations are working / have worked towards this new direction of carbon reduction. with a total of us$2,796bn funding, the us has invested a total of $973.0, that is, us$186.0 (useesa) and us$787.0 for usarra, while china invested $586.1 (robbins, clover and singh 2009). conclusion the crisis in climate, finance, and economy, among other sectors at the global and national levels reflect the way policy has ignored ecocentric principles and limitation in the concept and operation of anthropocentrism. specifically, pursuing the objectives, goals and interests of human beings without considering ecological principles or the inter -relatedness of human and non-human natural systems is responsible for the climate-environmental crisis. while the corruption of anthropocentric institutions, processes, structures and attitudes by top functionaries of global and national financial and economic systems has led to the crisis in these subsectors. the climate crisis is also the consequence of the way policy has ignored research-derived scientifically based information 011 afr. j. environ. econ. manage. and knowledge provided by think-tanks, ngos/csos and universities. this point is also applicable to the causes of the crises in finance and economy at global and national levels. the mitigation and adaptation to climate change and resuscitation of financial and economic systems will be successful if policy hearkens promptly to the researchderived information produced by think-tanks, universities and civil society in directing development plans and programmes. unfortunately, despite the energy crisis in africa in the form of gross inadequacy of electricity and the attendant disability of social and economic systems in africa, the adoption of sustainable (renewable and efficient) energy has been rather negligible, slow, and by far below the level in nations that are in the front line of green power implementation. recommendations the individual nation states in the membership of the african union generally and in sub-saharan africa in particular are by the foregoing findings of this study advised to encourage the creation and development of think-tanks that undertake research to produce information concerning various disciplines in the nexus of the development of both human and non-human natural environmental systems. it means that think-tanks with visions and missions to support or strengthen evidence based policy in human development (including economic management at global and national levels) and natural environmental sustainability deserve the attention, support and patronage of african governments. by impli-cation, the previous attitude of animosity championed by african governments that are almost solely interested selfperpetuation against ngos and csos does not bode well for development of the society generally and the environment and economy in particular. references 25 o in africa (2008). “wind energy prospers globally”, 25 0 in africa, pretoria (south africa-based) (africa’s independent energy publication) 3(1). ase (alliance to save energy) (2008). energy efficiency global forum & exposition (ee global), 27 – 29 april, 2009, paris (palais des congres de paris), (conference brochure), washington, dc: ase (www.ase.org). annan k (2006). an address by the un secretary-general (kofi annan) at the 12 th conference of parties to the united nations framework convention on climate change, 15 november, 2006, nairobi, kenya. arhenius s (1896). on the influence of carbonic acid in the air upon the temperature of the ground, philos. mag. 41: 237 – 276. babagana a (2007). “foreword from the african union” in mary hellmuth et al. climate risk management in africa: learning from practice. new york: int. res. institute climate soc. (iri) p. 104 bradbury j (2003). “think-tanks” in: mclean, i. and mcmillan, a. (eds). oxford concise dictionary of policy, (oxford & new york: oxford university press) p. 605. brown o (2008). “the numbers game” (in: climate change and displacement). forced migration review, issue 31, october: 8 – 9. byrne j, kurdgelashvili l, hudges k (2008). undoing atmospheric harm: civil action to shrink the carbon footprint, in: peter droege (ed.) urban energy transition (amsterdam: elsevier): pp.27 – 53. droege p (2008). “urban energy transition: an introduction” in peter droege (ed.) urban energy transition, amsterdam: elsevier: pp.1 – 14. haeckel e (1866). generalle morphologie. halliday j (2003). “darwinism” in ian mclean and allistar mcmillan (eds.) oxford concise dictionary of politics, oxford: oxford university press 606p. hansen j (2004). defusing the global warming time bomb. http://www.dbresearch.com (report on wind energy worldwide). sci. am. 290: 68 – 77. humphrey m (2003). “ecocentrism” in iain mclean and alistair mcmillan, (ed.) oxford concise dictionary of politics, oxford and new york: oxford university press 606p. humphrey m (2003). “global warming” in iain mclean and allistair mcmillan (eds.) oxford concise dictionary of politics, oxford: oxford university press 606p. ingwe r (2009). the response of nigerian universities to climate change (an article accepted for publication in proceedings of an international conference on climate change in turkey, october). ingwe, r (2008). review of the book by peter droege (ed.) urban energy transition, 2008. (march), amsterdam and other global cities: elsevier p. 655. ipcc (intergovernmental panel on climate change) (2001). climate change: synthesis report (ed. r. t. watson), cambridge: cambridge university press (available at: http://www.grida.no/ climate/ipcc_tar/col4/english/index.htm ipcc (intergovernmental panel on climate change) (2007). climate change: physical science basic, (cambridge, cambridge university press (available online at: http://ipccwgl.ucar.edu/wg1/wg1report.html khor, martin (2002). globalization and the south: some critical issues, (owerri: spectrum books limited) p.109. ki-moon b (2007). “foreword” in: united nations environment programme (unep) global environment outlook geo4: environment for development, valletta (malta): progress press ltd. mafuta c, lal m, yi h, stanners d, fernandez-gonzalez a (2007). “sustaining a common future” (chapter 6) in: unep. global environment outlook geo4 (environment for development), valletta: unep: pp195 – 226. myers n (2008). “environmental refugees: an emergent security issue” 13 th economic forum, may 2005. prague. www.osce.org/ document/eea/2005/14488en.pdf ngls (non-governmental liaison service) (2005). “kyoto protocol comes into force”. go between, no…, april – june. obama bh (2009) “inauguration remarks prepared for delivery by barack obama on 20 january at the united states capitol, washington, d.c., usa” huffington post. oppenheimer m, petsonk a (2005). article 2 of unfccc; historical origins, recent interpretations. climate change 73: 195 – 226. parry m, arnell n, mcmichael t, (2001). millions at risk: defining critical climate change threats and targets. global environ. change 11: 181 – 183. robbins n, glover r, singh c (2009). a climate for recovery: the colour of stimulus goes green. london: hsbc climate change global research. available online at: http://www.research.hsbc.com since february, retrieved on 3 rd april p.48. schneider sh, lane j (2006). an overview of “dangerous” climate change, in: avoiding dangerous climate change. scientific symposium on stabilization of green-house gases. february 1 st to 3 rd , 2005. met. office, exeter, united kingdom. published by the department for environment, food and rural affairs. stern n (2006). the economics of climate change – the stern review. cambridge, cambridge university press. stiglitz j, stern n (2009). obama’s chance to lead the green recovery (a paper published: march 2 2009 19:16 | last updated: march 2 (http://www.ft.com/cms/s/0/7c51644a-075b-11de-9294-000077b0765 8.html?nclick_check=1, 19: 16 the punch (2009). “eu pledges fresh 75 (billion) to fight crisis” 23 march; 21. ingwe et al. 012 the royal society (2005). joint science academies’ statement: global response to climate change. available at: http://www.royalsoc. ac.uk/document.asp?latest=1&id=3222. undp, unep, world bank and wri. (2005). world resources 2005: the wealth of the poor; managing ecosystems to fight poverty. washington, d.c.: wri. p.253. united nations (2007). the millennium development goals report, 2007. new york; united nations. 36p + charts. wri (world resources institute) (2006). world’s ghg emissions flow chart. available on the internet at: http://cait.wri.org/figures/ worldflowchart.pdf. in ternationa l scholars journa ls african journal of environmental economics and management issn 2375-0707 vol. 3 (3), pp. 221-224, march, 2015. available online at www.internationalscholarsjournals.org © international scholars journals author(s) retain the copyright of this article. short communication a study of the degradation of feather and hair wastes in an eco-friendly way so as to make the waste dumping soils fertile ashok patel 1 , shri kohli 2 and prakash kohli 2 1 college of environmental engineering, sardarkrushinagar dantiwada agricultural university, palanpur, gujarat, india. 2 department of environmental studies, faculty of agriculture, navsari agricultural university, navsari, gujarat, india accepted 21 january, 2015 the current study was aimed at the degradation of feather and hair wastes in an eco-friendly way, which should further be helpful to make the waste dumping soils fertile. degradation of feathers and hair was assessed by a highly potent keratinophilic fungus namely chrysosporium tropicum. the 60 day experiment was set up with sterile defatted feather and hair as substrates in a mineral medium along with the inoculum of the organism. the culture filtrate was analyzed every 10 days, for the release of catabolic products such as protein and keratinase, along with the concomitant increase in ph. maximum degradation was found on the 40th day sample, where the protein released was 6.9mg/ml and the keratinolytic activity was 8.56 ku/ml. the increase in ph (from neutral), towards alkalinity up to 40days (9.0) of incubation and decline thereafter, indicates that the release of soluble protein into the medium is maximum for 40 days. among the two substrates used, chrysosporium tropicum had more effect on hair than that of feather. key words: feather waste, hair waste, keratinophilic fungi, chrysosporium tropicum. introduction environmental pollution and degradation of ecosystem have assumed significance owing to an increase in the accumulation of wastes from industries, agriculture and poultry. in india, poultry feather, animal hair and other keratin sources do not find suitable applications. surveys conducted at different feather dumping soils in various places (ali-shtayeh et al., 2001; hubalek et al., krysztof, ali-shtayeh et al., vidal et al., 2000; moallaei et al., 2006; vidyasagar et al., 2003) all over the world (aleer rose, 1980; ali-shtayeh, 1989; dominik et al., 1964; filipello marchisio et al., 1991; merkantini et al., 1983; abdelhafez et al., 1987) including at various places in india (deshmukh, 1998; anbu et al., deshmukh, 2004; ramesh et al., 2002) and in-and-around visakhapatnam, indicated that several tons of poultry feather go as waste every day. corresponding author email: ashok_patel@gmail.com on the other hand, as andhra pradesh is the home of many religious pilgrim centers and people believe that hair is a symbolic offering to the gods, representing a real sacrifice of beauty and in return, are given blessings in proportion to their sacrifice, hair is becoming a major keratin material being dumped around temples and pilgrimages which causes the occurrence of too many keratinophilic fungal population in those soils. in general keratinophilic fungi are a group of fungi that colonize various keratinous substrates and degrade them to components of low molecular weight (harish, 2000). poultry feathers and human hair contain the major component of keratin. keratins are scleroproteins composed of long polypeptide chains, which are insoluble in dilute acids, alkali solutions and also resistant to the action of pepsin, trypsin and other non-substrate specific proteases because of their high content of cystine. the higher the percentage of sulfur, the higher is the stability of keratin towards solubilization (malcom, 2000). the disruption of insoluble keratin is generally believed to be an enzymatic process (deshmukh, 2004). ashok et al. 221 keratinases are the key enzymes elaborated by keratinophilic fungi for the degradation of keratin (tawfik et al., 2001; vidal et al., 2000). the enzyme is inducible and extra-cellular in nature. therefore, an attempt has been made to suggest the possibility of degradation of waste feather and hair by enzyme production in association with saprophytes with higher keratinolytic potential. material and methods c tropicum, a keratinolytic saprophyte isolated and identified (in comparison with that of strain procured from imtech, chandigarh – code: mtcc2821) from soil was maintained on potato dextrose agar medium (pda) (scrubbed and diced potaoes-200.0g; dextrose-20.0g; agar-15.0g; distilled water1000ml; ph-5.6). mineral medium was used for assay for keratin degradation (dipotassium hydrogen o-phosphate-1.500g; magnesium sulfate0.050g; calcium chloride-0.025g; ferrous sulfate-0.015g; zinc sulfate-0.005g; distilled water-1000ml; sterile defatted feather or hair -10g; ph-7.5). feathers or hair were defatted by soaking them in methanol-chloroform mixture (1:1) for 24 hours, washed with water and air dried. biochemical changes during hydrolysis of hair and feathers 50 ml of the prepared mineral medium with hair and feather was distributed in 250 ml erlenmayer’s flasks and were sterilized at 120 o c for 20 minutes. the liquid media were inoculated with 1 ml of spore suspension from the test fungi and incubated at 28±1 o c in static condition for a period of 60 days. during the period of incubation, samples were drawn at regular intervals of 10 days and analyzed to study the progress of feather degradation. the culture filtrate was centrifuged at 4000 rpm fro 5 minute. and the collected supernatant was used to assess the: 1. changes in ph (systronics ph meter) 2. estimation of protein (bradford, 1976) 3. determination of keratinolytic activity 4. changes in ph changes in ph:na clear cut evidence to assess the progress of poultry feather degradation was obtained by observing the changes in hydrogen ion concentration of the mineral media. the changes towards alkalinity of culture filtrate were measured by using a ph meter (systronics ph meter) with glass electrode. estimation of protein (bradford, 1976): to 1 ml of sample, 2 ml of coomassie brilliant blue solution was added and the absorbance was taken at 595 nm after 2 to 30 min. of incubation. amount of protein released in the culture filtrate was calculated with the help of standard prepared by using bovine serum albumin (bsa) as the substrate. coomassie brilliant blue solution: in a volumetric flask, 100mg coomassie brilliant blue g-250 was dissolved in 50ml of 95% ethanol. later 100ml of 85% phopshoric acid was added and diluted up to 500 ml with distilled water. this solution was filtered through whatmann no.1 filter paper and stored in cold room at 4 o c. determination of keratinolytic activity: keratinolytic activity was assayed by a modified method, using hair/feather as substrate. 20 mg of hair/feather from different temples, pilgrim and tonsure centers were cut into 1-3 mm long bits and were suspended in 3.5ml of tris-hcl buffer (0.1m, ph7.8) to which 0.2 ml of culture filtrate was added. the mixture was kept in a water bath at 37 o c for 1 h after incubation, the assay mixture was dipped in ice cold water for 10 min. and the remaining feather was filtered out. the optical density of clear mixture was measured by uv-visiblespectrophotometer at 280nm against corresponding blank that was prepared in the same way, instead of enzyme solution, buffer was added. enzyme unit: one unit of keratinolytic activity (ku) was the amount of enzyme that could liberate products having an absorbance of 0.1 under the assay condition (1ku=0.100 corrected absorbance) (kavitha et al., 2000). results and discussion the amount of catabolic degradative products such as protein and keratinase production along with the simultaneous increase in ph was an indication of feather degradation. changes in ph: the changes in ph towards alkalinity were assessed during hydrolysis. in all setups with c tropicum, there was a gradual increase in ph of the medium up to 40 days of incubation followed by decline thereafter (figure 1). the medium, set up for feather hydrolysis showed the ph: 7.9, 8.6, 8.8, 9.0, 8.5 and 7.9 while the setup for hair degradation showed the ph: 8.0, 8.8, 8.9, 9.2, 8.7 and 8.2 for 10th, 20th, 30th, 40th, 50th and 60th days respectively. the set up with hair as substrate has shown maximum change in ph (7.5 to 9.2) than that of the feather (7.4 to 9.0). the tendency towards alkalization of the medium may be due to the hydrolysis of feather and hair and the decline in ph at the end of the experiment may have been caused by the accumulation of degraded products especially acidic sulfur compounds in the media. this change in ph was an indicator for as well as preconditioner for keratinolysis (kavitha et al., 2000). estimation of protein: as shown in the figure 2, the maximum amount of protein was released by c tropicum, in 40th day sample (6.9mg/ml) and is same in both the cases where the feather and hair are used as substrates. a remarkable amount of protein was released by the keratinolytic activity of the c tropicum, from all the samples: 4.9mg/ml, 5.4mg/ml, 6.1mg/ml, 6.9mg/ml, 4.8mg/ml, and 4.2mg/ml for 10th, 20th, 30th, 40th, 50th and 60th days respectively, when feather was used as substrate. in accordance with the report of kavitha et al., (2000), waste feathers and hair are valuable organic sources because of their high content protein. determination of keratinolytic activity: among all the setup samples, maximum keratinase production registered 222 afr. j. environ. econ. manage. 10 9 8 7 p h 6 5 4 3 2 1 0 10 20 30 40 50 60 time of degradation (days) test (feather) control (feather) test (hair) control (hair) figure 1. changes in ph of mineral medium after degradation by chrysosporium tropicum. (m g /m l) 8 7 6 5 4 p ro te in 3 2 1 0 10 20 30 40 50 60 time of degradation (days) test (feather) control (feather) test (hair) control (hair) figure 2. estimation of protein after degradation by chrysosporium tropicum (mg/ml) was 8.56 ku/ml on the 40th day when hair was used as substrate. it is evident from the results (figure 3) that gradual increase in the keratinolytic activity of the c tropicum up to 40 days and decline thereafter, on both the feather and hair as substrates, occurred. the keratinolytic activity values when feather was used as a substrate are the following: 5.12 ku/ml, 7.02 ku/ml, 7.93ku/ml, 8.35ku/ml, 6.52ku/ml and 6.18ku/ml when feather was used as substrate, the keratinolytic activity values are: 6.77 ku/ml, 7.37 ku/ml, 8.14ku/ml, 8.56ku/ml, 6.50ku/ml and 5.92ku/ml when hair was used as substrate, for 10th, 20th, 30th, 40th, 50th and 60th days respectively. the results of the present study are in accordance with the work of bohme et al., (1969) that, deamination was ashok et al. 223 (k u /m l) 9 8 a c ti v it y 7 6 5 4 k e ra ti n o ly ti c 3 2 1 0 10 20 30 40 50 60 time of degradation (days) test (feather) control (feather) test (hair) control (hair) figure 3. determination of keratinolytic activity by chrysosporium tropicum (ku/ml) the key reaction of keratinolysis. in adding support to the view of present study, ramesh and hilda (1998) reported that the use of fungal keratinase was an industrial tool in the conversion of waste hairs into resource. the decline in keratinase activity on the 50th day may possibly be due to the end product inhibition caused by different catabolic degradative products of organic sulfur which is originally combined in feather and hair or due to the loss of accessory protein required for keratinase to act on feather or hair effectively. such a conclusion was in accordance with the findings of ramesh and hilda (1998) and kavitha et al., (2000). hence, it is evident from the present investigation that the fungal strain of c tropicum was a potent keratinolytic fungus both on feather and hair as substrate. acknowledgements the authors are grateful to university grants commission, new delhi for providing financial assistance and department of environmental studies, gitam university, visakhapatnam for providing laboratory facilities. references abdel-hafez a, el-sharouny hmm (1987). seasonal fluctuations of fungi in egyptian soil receiving city sewage effluents. cryptogamia, 8: 235240. aleer rmc (1980). investigation of keratinophilic fungi from soils in western australia premilinary survey. mycopathologia, 72: 155-165. ali-shtayeh, ms (1989). ecology of dermatophytes and other keratinophilic fungi in swimming pools and polluted and unpolluted streams. mycopathologia 2001, 156: 193-200. ali-shtayeh ms (???) keratinophilic fungi on sheep hairs from the west bank of jordan. mycopathologia, 106: 96-101. anbu p, hilda a, gopinath sc (2004). keratinophilic fungi of poultry farm and feather dumping soil in tamil nadu, india. mycopathologia, 158(3): 301-309. bradford mm (1976). rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye binding. anal. biochem., 72: 248-254. deshmukh sk (2004). isolation of dermatophytes and other keratinophilic fungi from the vicinity of salt pan soils of mumbai, india. mycopathologia 157: 265-267. deshmukh sk (2004). keratinophilic fungi on feather of pigeon in maharastra, india. mycoses., 47: 213-215. deshmukh sk (2002). incidence of dermatophytes and other keratinophilic fungi in glacier bank soils of the kashmir valley, india. british mycological society-mycologist (elsevier), 16(4): 165-167. dominik t, majchrowicz i (1964). isolating keratinophilic fungi from the soils of the cemeteries and forests of szczecin. ekologia. polakaseria. a, 12: 79-105. filipello mv, curetti d, cassinelli c, bordese c (1991). keratinolytic fungi in the soils of papua new guinea. mycopathologia, 115: 113119. hannelore b, ziegler h (1969). the distribution of dermatophytes and other keratinophilic fungi in relation to the ph of the soil. mycopathologia, 38(3): 247-255. harish cg (2000). non-dermatophytic filamentius keratinophilic fungi and their role in human infection. in revista ibero americana de mycologia; kushawa, r.k.s., guarro, j., eds.; bilbao, spain: 109114. hubalek z (2000). keratinophilic fungi associated with free living mammals and birds. in revista ibero americana de mycologia; kushawa, r.k.s., guarro, j., eds.; bilbao, spain: 93-103. kavitha ns, hilda ae (2000). hydrolysis of feather from different poultry strains by two species of aspergillus. polution res., 19(3): 331-335. krysztof ulfig. the occurrence of keratinophilic fungi in waste contaminated habitats. in revista ibero americana de mycologia; kushawa, r.k.s., guarro, j., eds.; bilbao, spain, 2000; pp. 45-50. 224 afr. j. environ. econ. manage. malcom r, michael e (2000). model systems for the study of dermatophyte and non dermatophyte invasion of human keratin. in revista ibero americana de mycologia; kushawa, r.k.s., guarro, j., eds.; bilbao, spain: 115-121. merkantini r, marsella r, labiase l, fulvi f (1983). isolation of keratinophilic fungi from floors in roman primary schools. mycopathologia 82: 115-120. moallaei ??? provide names and initials of other authors. (2006). isolation of keratinophilic fungi from soil samples of forests and farm yards. iranian j. pub. health 35(4): 62-69. mohamed sa, rana mfj (2000). keratinophilic fungi and related dermatophytes in polluted soil and water habitats. in revista ibero americana de mycologia; kushawa, r.k.s., guarro, j., eds.; bilbao, spain: 51-59. ramesh vm, hilda a (1998). incidence of keratinophilic fungi in the soils of primary schools and public parks of madras city, india. mycopathologia, 143: 139-145. tawfik, m, mushin r, hadi b (2001). degradation of keratin substrates by fungi isolated from sewage sludge. mycopathologia, 154: 185189. vidal p, sanchez pjm, milan dg (2000). chrysosporium fluviale a new keratinophilic species from river sediments. mycol. res. 104: 244250. vidyasagar gm (2003). keratinophilic fungi isolated from hospital dust and soils of public places at gulbarga, india. mycopathologia, 159: 13-21. african journal of environmental economics and management vol. 1 (3), pp. 072-075, october, 2013. available online at www.internationalscholarsjournals.org © international scholars journals full length research paper environmental audit behaviour, decision pattern, and market performance of small and medium enterprises in nigeria eseroghene franklin udjo department of business administration, al-faisal university, prince sultan college of tourism and business, abha-saudi arabia. e-mail: udjo.ese@pscabha.edu.sa. tel: +9667231800 (ext.324), +966562088801. accepted 20 june, 2013 the environmental audit behaviour and decision making pattern of nigerian smes is obscure. given the fact that the nigerian business environment is turbulent, the study finds out whether the decision making process of nigerian smes is contingent upon information from the business environment. the study, utilizing correlation statistical procedure examines the subject of discourse. the results of the study suggest that the analysis of technological, customer and competitive factors have partial effect on the market share of nigerian smes. conversely, the analysis of socio-cultural factor of the nigerian business environment has inverse effect on the market share of the smes. the study concludes that the environmental audit behaviour of nigerian smes have partial effect on market performance. key words: business environment, economic factor, political factor, socio-cultural factor, technological factor. introduction small and medium enterprises (smes) are submerged in environments that are characterised by varying degree of uncertainty. environmental uncertainty represents changes in the political, socio-cultural, technological, economic, customer and competitive factors that constitute a business environment. the degree of environmental change of a business environment can be identified as mild or turbulent. changes in the nigerian business environment occur rapidly such that it can be described as turbulent. the turbulent changes occurring in the nigerian business environment have imposed economic pressure on the competitiveness of nigerian smes and have weakened their market performance. to remedy this situation, it is expected that smes put in place decisions that are effective. effective decisions are those that are capable of mitigating the impact of environmental uncertainty. a necessary condition required to put in place decisions that are effective is to thoroughly understand the dimensions of the environmental factors that are responsible for the turbulence. in light of this, nigerian smes must understand and anticipate the opportunities and threats the turbulent business environment presents. however, kotler (2001) remarked that the dynamics in most business environments fast out-pace the capability of smes to keep abreast with the changing trends. if this is the case, it becomes logical to get puzzled as to how nigerian smes make decisions. to put this research in perspective, the study poses the following questions: do the decision making process of nigerian smes contingent upon information from the business environment? or do they tend to use intuitive methods? in either choice, do the decisions mediate the effects of environmental uncertainty such that market performance is significantly improved? an attempt to provide answers to these questions gives the rationale for this study. environmental analysis and strategic fit of nigerian smes abbreviation: smes, small and medium enterprises. the analysis of the business environment is pre-requisite udjo 072 to making effective decisions (beale, 2000). environmental analysis is the internal communication of external information about issues that can have potential effect on the market positions of smes. albright (2004) noted that the process of environmental analysis comprised of five steps: identify the environmental information; gather the information; analyze the information; communicate the information and results; and make informed decisions. nigerian smes face plethora of challenges in carrying out these tasks. these challenges include poor managerial skills, poor technical skills and inadequate finance (ogunsiji, 2002; akande and laduna, 2010; olutunla and obamuyi, 2008). in analysing the business environment managerial skills are required to diagnose the threats and opportunities that lie therein, technical skills are required to synthesize the nature and complexity of the interaction of the threats and opportunities and capital is needed to finance the inputs associated with these arduous tasks. if nigerian smes lack these core capabilities, it will not be overemphasis to state that the spates of closure of smes in nigeria are adduced to a lack of these essential requirements. inputs from the business environment enable smes to create “strategic fit” with the environments in which they operate. to create a strategic fit, zhang and lado (2001) divided the tasks involved into two phases. according to these authors, the first phase entails scanning of information from the micro and macro environments. the analysis of the information yields intelligence which is utilized for strategic decisions. the second phase comprised of four activities namely: strategic formulation; corporate capability; real time strategic response and the implementation of the strategies. on the basis of environmental analysis, smes are likely to achieve higher sales growth, high market share, high returns on assets, and high margins on profit (carland and carland, 2003; gibson and casser, 2005). similarly, smes tend to be more innovative, employ new processes and achieve international growth if their decisions are contingent on a thorough understanding of the business environment (lucio et al., 2002; beaver and prince, 2002; jocumsen, 2004). it is evident from the foregoing that environmental analysis is critical to the survival of smes in today’s rapidly changing business environments. given the importance of environmental analysis, it is pertinent to examine the way nigerian smes create the so-called strategic fit. conceptual framework and hypotheses the conceptual framework considers two paths to decision making by nigerian smes (figure 1). the first path presumes that smes scan the turbulent business environment for the purpose of data collection. the data generated are analysed and transformed into useful information. on the basis of the information, smes make their decisions. this postulate leads to the six (6) hypotheses which states that: h1a: there is significant relationship between decisions made based on information about technological variables and market share of nigerian smes. h1b: there is significant relationship between decisions made based on information about socio-cultural variables and market share of nigerian smes. h1c: there is significant relationship between decisions made based on information about economic variables and market share of nigerian smes. h1d: there is significant relationship between decisions made based on information about political variables and market share of nigerian smes. h1e: there is significant relationship between decisions made based on information about customers’ and market share of nigerian smes. h1f: there is significant relationship between decisions made based on information about competitive variables and market share of nigerian smes. the framework asserts in the second path that smes are perplexed with the interconnectedness of the factors that constitute the nigerian business environment. for this reason, they are unable to discern the environmental factors that constitute threats and opportunities. in light of this assumption, smes chooses to intuitively make decisions which are guided by needs and values of decision makers. against this backdrop, the study hypothesizes that: h2: there is significant relationship between decisions made based on intuition and market share of nigerian smes. materials and methods the sampling frame for the study was collected from the corporate affairs commission, abuja. the frame contains list of registered companies on industry basis. from the frame, probability sampling technique was used to select the 129 smes that were studied. the 129 smes satisfy the european union (2003) definition of small and medium sized enterprises. although, a total of 147 smes were originally sampled, the responses from 129 smes were found useful. the questionnaire used to generate the research data examined environmental issues relating to technological, socio-cultural, economic, political, customer and competitive factors. these factors were measured on a five point likert scale ranging from 1 (strongly disagree) to 5 (strongly agree). these factors according to kotler (2001) constitute the effective ingredients of a business environment. market share, which is a prime measure of market performance was also measured on a five point likert scale ranging from 1 (strongly disagree) to 5 (strongly agree). decision making pattern was examined by asking if smes decision making activities are based on information from the business environment or not. in other words, decision making pattern was measured using udjo 11165 073 afr. j. environ. econ. manage. figure1. the conceptual model. dichotomous scale. the data generated was subjected to descriptive and correlation analyses. results the result of the descriptive analysis is shown in table 1. according to the table, the decision making pattern of 56 smes is based on information from the turbulent business environment. this accounts for 43.4% of the sampled smes. 73 smes based their decision making activities on intuition. this accounts for 56.6%. the result of the correlation analysis is presented in table 2. according to the table, one of the four items used to measure technological factor of the nigerian business environment shows positive correlation with market share (r = 0.463, p ≤ 0.01). similarly, one of the three items used to measure socio-cultural factor reveals statistical significance with market share (r = -0.186, p ≤ 0.05). there is no correlation found between market share and economic factor as well as between market share and political factor of the nigerian business environment. one of the five items used to measure customer factor correlated with market share (r = 0.411, p ≤ 0.01). the analysis of industry competition indicates that one of the four items used to measure this factor shows statistical association with market share (r= 0.378, p≤ 0.01). the examination of the relationship between decision making based solely on intuition and market share indicates inverse statistical association (r= -0.252, p≤ 0.01). discussion the results of the correlation analyses reveal that technological factor partially promotes the market position of nigerian smes. this is as a result of the correlation of one of the four items used in measuring this factor. the study therefore partially accepts h1a. the test of h1b reveals inverse relationship between market share and socio-cultural factor. this indicates that the market performance of nigerian smes decreases as they engage in the analysis of the socio attributes of the nigerian business environment. on the basis of this, h1b is partially accepted. the tests relating to h1c and h1d did not show statistical significance. these results indicate that the analyses of these two factors do not have impact on the market performance of nigerian smes. in light of this, the study refutes h1c, h1d and h1e is partially accepted because one of the five items used in measuring customer factor shows statistical significance with market share. udjo 074 table 1. decision based solely on environmental information. frequency percent valid percent cumulative percent yes 56 43.4 43.4 43.4 valid no 73 56.6 56.6 56.6 total 129 100.0 100.0 100.0 table 2. correlation. decision based on information from the business environment analysis of socio cultural factor market share we have a strong commitment to knowing the population size and distribution -.186* we have a strong commitment to knowing the age distribution of the population .095 we have a strong commitment to knowing the income distribution of the population -.088 analysis of technological factor market share we have a strong commitment to knowing new manufacturing processes -.162 we have a strong commitment to knowing new products and services of our competitors .057 we have a strong commitment to knowing new technology that could impact our enterprise .463** we have a strong commitment to knowing the costs and accessibility of electrical power .041 analysis of political factor market share we have a strong commitment to knowing the political stability and risks pertaining to our enterprise .002 we have a strong commitment to knowing the budget deficit or surplus .103 we have a strong commitment to knowing the copyright and patent laws -.084 we have a strong commitment to knowing the minimum wage laws -.072 analysis of economic factor market share we have a strong commitment to knowing the gdp and per capita -.053 we have a strong commitment to knowing the unemployment rate .041 we have a strong commitment to knowing the current exchange rates -.114 we have a strong commitment to knowing the consumers and investors confidence -.154 we have a strong commitment to knowing the economic growth -.098 we have a strong commitment to knowing the inflation rate .028 analysis of the customer market share the enterprise always look forward to finding new ways of creating customer value in our products -.013 the enterprise encourages customer feedback .054 the enterprise measures customer satisfaction on a regular basis -.077 the enterprise’s objectives are customer driven .102 the enterprise has a strong commitment to customers .411** analysis of industry competition market share the enterprise responds rapidly to competitors actions .378** the enterprise regularly collects data on competitors activities -.168 the enterprise regularly monitors competitors marketing activities -.066 the enterprise regularly collects data on industry competition .097 intuition -.252** ** correlation is significant at the 0.01 level (2-tailed). 075 afr. j. environ. econ. manage. the relationship indicates that the market performances of nigerian smes appreciate as a result of engaging in analyzing the customer. the study partially accepts h1f. this is due to the fact that one of the four items used to measure industry competition correlated with market share. this suggests that the analysis of industry competition have partial impact on the market performance of nigerian smes. the analysis further reveal that decision based on intuition have partial correlation with market share. in view of this, h2 is partially accepted. the nature of the partial correlation shows inverse relationship. this suggests that that the market performance of nigerian smes is negatively affected when decisions are based on intuition. the partial nature of the correlations corroborates the view that nigerian smes lack the managerial skills, technical skills and finance to carry out effective audit of the turbulent business environment (ogunsiji, 2002; olutunla and obamuyi, 2008; akande and ladanu, 2010). conclusion this paper examines the moderating effect of environmental audit on market performance of nigerian smes. the results reveal that the environmental audit of nigerian smes has partial effect on market performance. specifically, in quest to improve market performance, nigerian smes attempt to analyse the technological, customer and competitive factors of the business environment. udjo 11167 references akande oo, ojokuku rm (2008). the impact of entrepreneurial skills on small business performance in lagos-south-western nigeria. paper presented at international council for small business. 53 rd world conference, halifax, nova scotia, canada. albright k (2000). environmental scanning: radar for success. info manage. j., lemexa, may/june, pp. 38-45. beale r (2000). competing effectively: environmental scanning, competitive strategy, and organizational performance in small manufacturing firms. j. small bus. manage., 38: 27-48. beaver g, prince c (2002). innovation, entrepreneurship and competitive advantage in the entrepreneurial venture. j. small bus. entrep. dev., 9: 28-37. carland jc, carland jw (2003). pawn takes queen: the strategic gameboard in entrepreneurial firms. acad. strateg. manage. j., 2: 93-104. gibson b, casser g (2005). longitudinal analysis of relationships between planning and performance in small firms. small bus. econ., 25(3): 207-222. jocumsen g (2004). how do small business managers make strategic marketing decisions? a model of process. eur. j. mark., 38(5/6): 659-674. kotler p (2001). strategic marketing management. 3 rd edition. ingo leung. lucio w, hormozi, am, sutton gs, mcminn rd (2002). business plan for new or small businesses: paving the path to success. manage. decis,. 40(8): 755 -763. ogunsiji as (2002). agricultural credit strategies and productivity performance of small scale agro-based industries. res com. manage., 1(2): 42-50. olutunla gt, obamuyi tm (2008). an empirical analysis of factors associated with the profitability of small and mediumenterprises in nigeria. afr. j. bus. manage., 2(10): 195-200. zhang m, lado a (2001). information systems and competitive advantage: a competency –based view. technovation, 21:147-156. in ternationa l scholars journa ls african journal of environmental economics and management issn 2375-0707 vol. 3 (2), pp. 218-220, february, 2015. available online at www.internationalscholarsjournals.org © international scholars journals author(s) retain the copyright of this article. short communication an investigation on the income accruing to sorghumrice enterprise in response to the most profitable mixture combination for adoption by farmers *bayo paul1, bolanle akiolu2 and yemi philips2 1 department of crop science, faculty of agriculture, ajayi crowther university, oyo, oyo state, nigeria. 2 department of environmental management, faculty of agriculture, afe babalola university, ado-ekiti, ekiti state, nigeria. accepted 22 january 2015 multiple cropping offers farmers the opportunity to engage nature’s principles of diversity on farms. a field trial that was conducted in nigeria, investigated the yield and economic returns that accrued to sorghum and rice; in sorghum – rice intercrop as affected by rice inclusion in the proportions: 1:1, 1:2, 1:3 and 1:4, respectively for sorghum and rice. analysis of yield data for both cropping seasons revealed significant influence of sorghum – rice intercrop on grain yields of sorghum and rice in mixtures. observed average sorghum yield in sole plot was 1712.39 kg ha -1 , which was progressively significantly decreased with progressive inclusion of rice rows from 1050.58 kg ha -1 (38.65 % yield reduction) in 1:1 sorghum – rice mixture to 300.35 kg ha -1 (82.46% yield reduction) in 1:4 sorghum – rice mixture; while grain yields of sorghum decreased with progressive rice inclusion, grain yields of rice increased per hectare with progressive increase in rice rows from 1:1 to 1:4. considering the economic implication of intercropping sorghum with rice, income that accrued to sole crops was significantly reduced with intercropping. while all the crop combinations investigated performed better than sole cropped sorghum (in terms of revenue generation), sole rice performed better than all the intercrops. the implication of this observation is that while sorghum is better intercropped with rice to improve revenue generation, rice is best as sole crop. in conclusion, in sorghum – rice intercrop, intercropping at 1:4 is recommended as this mixture gave best intercrop result in respect to monetary return relative to other mixtures. key words: intercropping, monetary returns, multiple cropping. rice, sorghum, yield. introduction the deepening need for increasing productivity on farmers’ plots in the african continent will be met through better understanding of crop environment, particularly as it regards to multiple cropping systems, which offer farmers the opportunity to engage nature’s principles of diversity on farms. by combining crops of different growing periods, varying heights and varying uses, african farmers have evolved highly diversified cropping systems (okigbo and greenland, 1976; steiner, 1982). *corresponding author e-mail: bayopaul@yahoo.com however, spatial arrangements of crops, sowing rates and crop maturity date are important considerations when planning these multiple cropping systems (sulivan, 2010). generally, the rationale of intercropping lies in its beneficial effects. besides allowing the farmer to grow various crops on a piece of land without necessarily preparing another land, an insurance against total crop failure, helping in the control of erosion, pests and diseases, it provides the farmer a variety of crops, thus improving his dietary intake (kassam, 1972; steiner, 1982; langdale et al., 1992) and securing farmers income. besides combined yield advantage that may come with multiple cropping, farmers should also be interested in the economic implication of the system they bayo et al. 218 table 1. average yield implication of sorghum (sorghum bicolor) and rice (oryza sativa l) intercrop as influenced by varying mixture proportion. treatment intercrop effect on crop yield sorghum rice sorghum: average intercrop implication percentage yield average intercrop implication percentage yield rice grain yield relative to sole crop reduction relative to grain yield relative to sole crop reduction relative to (kg ha -1 ) (kg ha -1 ) sole crop (kg ha -1 ) (kg ha -1 ) sole crop sole 1712.39a 1405.39a 1:1 1050.58b 661.81 38.65% 760.67e 644.72 45.87 1:2 571.83c 1140.56 66.61% 933.82d 471.57 33.55 1:3 446.15d 1266.24 73.95% 994.67c 410.72 29.22 1:4 300.35e 1412.04 82.46% 1113.05b 292.34 20.80 se± 28.623 22.050 are engaged in what is the cost implication of such a system and the likely economic returns to the system. the food sub-sector of nigeria’s semi-arid agriculture parades a large array of cereal crops, made possible by the diversity of agro-ecological production systems (rowland, 1993). presently, rice is a common dietary staple in nigeria and individuals now consume 21 kg of rice annually, representing 9% of total caloric intake and 23% of the total cereal consumption, with an estimated 2.1 million tonnes of rice consumed annually by the populace (ukwungwu et al., 2004). an estimated 0.4 million tonnes of rice enters the country annually (ukwungwu et al., 2004). sorghum is no less important, a common staple among the poor (noting that more than 70 per cent of the populace fall below the poverty line of one dollar a day) and the drier part of the country. the importance of sorghum and rice in the diet of most nigerians justify a study on these crops. especially, considering that rice have risen to a position of preeminence. the fact that over 75 per cent of cultivated land in nigeria is, sown to more than one crop type, justifies a study on multiple cropping system. this research thus investigated the income that accrued to sorghum-rice enterprise in response to varying mixture combinations with the aim of finding the most profitable mixture combination for adoption by farmers. materials and methods on farm trials conducted in 2006 and 2007 wet seasons in loko, tudu uku local government areas of nasarawa state, nigeria; southern guinea savanna agro-ecological zone (latitude 8 0 00 1 19 0 n; longitude 7 0 50 1 39 0 e) investigated the response of sorghum and rice to varying levels of intercropping. the field was ploughed and harrowed without ridging. sorghum: samsorg 14 (ksv8), sourced from the institute for agricultural research (iar), zaria was sown 25 by 90 cm intra and inter row for sole crop plots. for intercropped plots, rice variety: ita 257 was dibbled between sorghum rows at 30 by 30 cm inter and intra row spacing at 1:1; 1:2; 1:3 and 1:4 rows, respectively for sorghum and rice, using row substitution method as reported by yahaya et al. (2005). one, two, three and four rows of sorghum stands were replaced with rice in the proportions of 1:1, 1:2, 1:3 and 1:4, respectively in line with yahaya et al. (2005). three and six seeds of sorghum and rice respectively, were sown and thinned to one plant/stand of sorghum and four plant/stand of rice two weeks after sowing. sorghum crop received fertilizer application: 64 kg n, 13.2 kg p and 26.4 kg k in two split doses at planting and 6 was to sorghum, while rice received 80 kg n as against the fertilizer rate given to sorghum with other nutrients maintained as in sorghum crop. data was collected on crop yield, yield implication of intercropping relative to sole cropping (kg ha -1 ), percentage, yield implication of intercropping relative to sole cropping, monetary implication of the cropping systems and monetary implication of intercropping relative to sole cropping. returns on sorghum enterprise was calculated based on an average of n50 kg -1 of grain sorghum as at october 2010 while rice enterprise was based on an average of n140 kg -1 of rice grains kg -1 within the same period. thus, economic returns to the enterprise were, derived as in the formulae: rs = ys x cs rr = yr x cr where rs = revenue that accrued to sorghum (n) ys = yield of sorghum per ha (kg) cs of sorghum per kg rr = revenue that accrued to rice (n) yr = yield of rice per ha (kg) cr = cost of rice per kg (n) results and discussion analysis of yield data for both cropping seasons revealed significant influence of sorghum – rice intercrop on grain yields of sorghum and rice in various mixtures. observed average sorghum yield in sole plot was 1712.39 kg ha -1 , which was progressively significantly decreased with progressive inclusion of rice rows from 1050.58 kg ha -1 (38.65% yield reduction) in 1:1 sorghum – rice mixture to 300.35 kg ha -1 (82.46% yield reduction) in 1:4 sorghum – rice mixture (table 1). while grain yields of sorghum decreased with progressive rice inclusion, grain yields of 219 afr. j. environ. econ. manage. table 2. monetary returns on sorghum (sorghum bicolor) rice (oryza sativa l) enterprise ($ ha -1 ) as influenced by varying mixture proportion treatment intercrop effect sorghum rice sorghum: average grain monetary intercrop implication average grain monetary intercrop implication rice yield (kg ha -1 ) implication ( n ) relative to sole crop ( n ) yield (kg ha -1 ) implication ( n ) relative to sole crop ( n ) sole 1712.39a 85,619.50 1405.39a 196,754.60 1:1 1050.58b 52,529.00 33,090.50 760.67e 106,493.80 -90,260.80 1:2 571.83c 28,591.50 -57,028.00 933.82d 130,734.80 -66,019.80 1:3 446.15d 22,307.50 -63,312.00 994.67c 139,253.80 -57,500.80 1:4 300.35e 15,017.50 70,602.00 1113.05b 155,827.00 -40,927.60 se± 28.623 22.050 *exchange rate: n150.6024 to $1 rice increased per hectare with progressive increase in rice rows from 1:1 through to 1:4. however, the highest grain yields for both sorghum and rice were, observed in sole plots, which significantly decreased with intercropping. the observed yield reduction in the intercrops were not necessarily the result of reduction in yield capacity of individual stands, but rather the effect of reduced individual component crop population with intercropping (oyewole, 2004). it should be noted that in crops that tiller, such as sorghum and rice, reduction in plant population, which accompanies intercropping, may actually boost yields of individual crop stands as a result, of profuse tiller formation with lowered population (oyewole et al., 2010). this fact is glaring when one observes the percentage yield reduction that accompanied progressive rice inclusion in the intercrop shown on table 1. with 1:1 row mixture, grain yield reduction was 38.65%, which almost doubled with 1:2 row mixtures (66.61% yield reduction). however, the differences in grain yields between 1:2 and 1:3 and between 1:3 and 1:4 row mixtures were less than 10%. an indication that reduction in sorghum population must have prompted a boost in stand yields in the intercrops, either as a result of profuse tiller formation or heavier seed weight. usually, the profitability of multiple cropping rests on the ability of the component crops to compensate for yield reduction through attainment of better combine yield. where this occurs, observed reduction in individual crop is often over-matched, by the combined yields of component crops in the mixture. the combined effect of individual crop yield is difficult to quantify except where expressed in monetary terms. thus, table 2 attempts an interpretation of what is contained on table 1 in monetary terms. this is to give a common scale of measurement to this different enterprise upon which to assess enterprise profitability. considering the economic implication of intercropping sorghum with rice, income that accrued to sole crops was n85, 619.50 and n196, 754.60, respectively for sorghum and rice, which were significantly reduced with intercropping (table 2). the least monetary return on sorghum enterprise was in 1:4 cropping ratios (n15, 017.50), n70, 602.00 less the return in sole plots, while the least monetary return on rice enterprise was in 1:1 crop combination (n106, 493.80), n 90,260.80 less the return on sole cropped rice. combined monetary return on sole crops was n282,374.10 which decreased by n123,351.30 in 1:1 cropping ratios, by 123,047.80 in 1:2 cropping ratios, by n120,812.80 in 1:3 crop combination while 1:4 cropping ratios recorded n111,529.60 reduction in income in comparison with sole crops (table 3). thus 1:1 cropping ratios recorded the highest revenue reduction in comparison with sole crops, while the least revenue reduction was in 1:4 crop combination. while all the crop combinations investigated performed better than sole cropped sorghum (in terms of revenue generation), sole rice performed better than all the intercrops (table 3). the implication of this observation is that while sorghum is better intercropped with rice to improve revenue generation, rice is best as sole crop. conclusion trial conducted in nasarawa state, nigeria, investigated yield and economic returns that accrued to sorghum and rice in sorghum – rice intercrop as affected by rice inclusion in the proportions of: 1:1, 1:2, 1:3 and 1:4, respectively for sorghum and rice. analysis of yield data for both cropping seasons revealed significant influence of sorghum – rice intercrop on grain yields of sorghum and rice. grain yield of sorghum decreased with progressive rice row inclusion, while grain yield of rice increased per hectare with progressive increase in rice rows. considering the economic implication of intercropping sorghum with rice, income that accrued to sole crops was bayo et al. 220 table 3. monetary returns on sorghum (sorghum bicolor) rice (oryza sativa l) enterprise (n ha -1 ) as influenced by varying mixture proportion. treatment monetary implication of the intercrop ( n ) sorghum rice total intercrop implication relative to sole crop sorghum: rice sole 85,619.50 196,754.60 282,374.10 1:1 52,529.00 106,493.8 159,022.80 -123,351.30 1:2 28,591.50 130,734.80 159326.30 -123,047.80 1:3 22,307.50 139,253.80 161,561.30 -120,812.80 1:4 15,017.50 155,827.00 170,844.50 -111,529.60 * exchange rate: n150.6024 to $1 significantly reduced with intercropping. while all the crop combinations investigated performed better than sole cropped sorghum (in terms of revenue generation), sole rice performed better than all the intercrops. the implication of this observation is that while sorghum is better intercropped with rice to improve revenue generation, rice is best as sole crop. in conclusion, in sorghum – rice intercrop, intercropping at 1:4 is recommended as this mixture gave best intercrop result in respect of monetary return relative to other mixtures. references kassam ah (1972). crops of west african semi-arid tropics. in: aliyu, u. (2001). varietal response to spacing and effects of applied phosphorus and manure on the growth and yield of groundnut (arachis hypogaea l.), m. sc dissertation presented to crop science dept. faculty of agriculture, usmanu danfodiyu university, sokoto, 106 pp langdale gw, clark rl, bruce rr (1992). the role of legumes in sustaining soil productivity and controlling soil erosion. in: biological nitrogen fixation and sustainability of tropical agriculture (mulongoy k. m.; gueye, m. and spencer, d. s. c. eds). proceedings of the fourth international conference of the african association for biological nitrogen fixation (aabnf), held at the international institute of tropical agriculture (iita), ibadan, nigeria, 24-28 sept. 1990. john wiley and son, united kingdom pp 361-365 okigbo bn, greenland dj (1976). inter cropping systems. in: multiple cropping special publication (papendrid, r. j.; p. a. sanchez and g. b. triplet ed) 27: 63-101 oyewole ci (2004). effect of cropping pattern, p and k fertilizers on the growth and yield of millet and groundnut in millet/groundnut mixture in the sudan savanna. ph. d thesis presented to post-graduate school, usmanu danfodiyo university, sokoto 117pp oyewole ci, ajayi o, ojuekaiye ro (2010). evaluation of seven upland rice (oryzae sativa) cultivars by three sowing methods in anyigba, kogi state, nigeria. afr. j.agric. res 5(16): 2089-2096 rowland jrj, whiteman p (1993). principles of dry land farming. in: dry land farming in africa (rowland, j.r.j ed ). macmillan london press ltd pp68 – 94 steiner kg (1982). intercropping in the tropical small -holder agriculture with special reference to west africa. german agency for technical cooperation (gtz) postfash 5180, d-eschborn / ts. 1. 303 pp sulivan p (2010). intercropping principles and production practices http://attra.ncat.org/attra-pub/intercrop.htm1 14pp ukwungwu mn, imolehin ed, olaniyan go, fademi ao, kehinde jk, bright eo, maji ea, gana mat, abo me, ojehomon vet, agboire l, lagoke sto, adagba ma, singh bn (2004). rice. in: cereal crops of nigeria: principles of production and utilization, xxii 337 (idem, n.u.a. and showemimo, f.a. eds): 115-188 yahaya ra, elemo ka, aliyu l, odion ec, babaji ba (2005). yield and yield components of sorghum (sorghum bicolor) and rice (oryza sativa l) intercrop as influenced by proportion and rice thinning of in samaru. j. trop. biosci. 5(2): 42-4 african journal of environmental economics and management vol. 1 (5), pp. 120-125, december, 2013. available online at www.internationalscholarsjournals.org © international scholars journals full length research paper willingness to pay for protecting natural environments in pulau redang marine park, malaysia mohd parid mamat 1 , mohd rusli yacob 2* , alias radam 2 , awang noor abdul ghani 3 and lim hin fui 1 1 forest research institute malaysia, 52109 kepong, selangor darul ehsan, malaysia. 2 faculty of economics and management, university putra malaysia, 43400 upm serdang, selangor, malaysia. 3 faculty of forestry, university putra malaysia, 43400 upm serdang, selangor, malaysia. *corresponding author. e-mail: mroy@econ.upm.edu.my. accepted 8 july, 2013 although marine parks, national parks, wildlife sanctuaries and reserves are established to conserve biodiversity and enhance ecotourism, some of the country’s protected areas are under threat whether at varying degree. the biggest threat arises from human encroachment. to rescue these resources, appropriate conservation strategy must be put in place. this requires proper valuation of the environment. taking pulau redang marine park (prmp) as a case, information on people’s willingness to pay (wtp) to protect the environment was gathered. using the dichotomous-choice contingentvaluation method (cvm), it was found that the recreationists are willing to protect the park. the study showed that the average wtp ranged between rm10.86 and rm28.69 that could contribute between rm1.65 million and rm4.36 million in aggregate for the year 2008. key words: contingent valuation method, ecotourism, marine park, sustainable development, conservation and economic valuation, malaysia. introduction the value of protected natural environments is important in decision-making in an increasingly natural-resourcescarce world. natural environment includes protected areas such as forest reserves and marine parks which are also potential ecotourism areas. the increasing demand for tourism has led to the development of infrastructure facilities, particularly the development for natural ecotourism areas. however, the economic benefits of natural ecotourism areas are not readily known because of unavailable market price. this is true for the marine resources where the potential and realized benefits for recreation purposes are not valued. if this is not done, the allocation of marine resources cannot be determined optimally and conversion for other purposes might be possible. quantifying the economic value of natural environment resources can show where goods and services are currently underpriced by the market. it can also indicate whether there is potential to develop new markets, to charge prices for the use of natural resources or to capture natural resource benefits as cash values. other than generating revenues, prices and market measures can provide an effective means of regulating the demand for resources and of providing incentives for sustainable management. demonstrating the economic value of natural resources can make a convincing case for the conservation of the ecosystem. higgins and turpie (1997), for example, valued south africa‟s mountain fybos ecosystems in order to argue for increasing funding and protection. spurgeon (1998) showed how valuation can be used to support ecosystem rehabilitation and protection in coastal and marine habitats. kumari (1995, 1996) calculated the mamat et al. 120 economic values of forest and wetlands in north selangor to make the case for increased international financing to secure global benefits. specifically, for the case of protected area, the valuation of economic benefits through willingness to pay (wtp) can be used to defend the gazetting of new locations or to argue against changes in their protected status. emerton et al. (1999), for example, calculated the economic value of ecosystem services and livelihood benefits from nakivubo wetland in kampala, uganda, at more than usd1.5 million a year, using the results to make a strong case for it to be protected as part of the city‟s green belt. pulau redang marine park (prmp), malaysia pulau redang marine park is located about 45 km (24.2 nautical miles) north-northeast of kuala terengganu. currently, the population on the island was about 1300 people from more than 200 families. they engage in traditional fishing related activities and supplement their income from petty trading, harvesting of natural resources such as edible birds‟ nest from the swiflet colonies or guarding of turtle nests and eggs for the department of fisheries malaysia. some of them are also involved in the tourism activities, as tour boat operators, tourist guides or tour boatmen and assistants. redang island offers crystal clear waters and numerous diving sites for enthusiasts. redang island and other several islands in the archipelago are recognized as having one of the best corals and marine ecosystems in malaysia. the waters surrounding these islands were gazetted as part of the pulau redang marine park, under the establishment of marine park malaysia order 1994 (fisheries act 1995). the boundary of the marine park is established by a line linking all points to nautical miles from the shores (low water mark) of pulau redang and several other smaller islands, that is, lima, ekor tebu and pinang. the largest island is pulau redang, which is about 25 km 2 (9.5 mile 2 ) in area, and is dominated by two imposing north-south ridges separated by a low-lying central valley. the coast on the eastern side of the island is blessed with sweeping, white sandy beaches, while the western side is wilder, rockier in nature. the vegetation on the island is lush, characterized by varied forest types. the goals of the pulau redang marine park are to protect, conserve and manage in perpetuity marine environment of significance and to encourage public understanding, appreciation and enjoyment of malaysia‟s natural heritage by present and future generations. this paradise island is perfect for snokerling, swimming, scuba diving, jungle trekking, boating and canoeing. materials and methods surveying visitors or recreationists is done by using a structured questionnaire, the source of primary data. before the questions were asked, the respondents were briefed on the objectives and the purpose of the survey. the questionnaire was administered in a single interview with every respondent. an interviewing session for a respondent took about 30 40 min. the approach of cvm for this study used the dichotomous choice – double bounded format. the format gives the respondent an apportunity to choose the amount of wtp. through this format, the response „yes‟ or „no‟ was needed for the wtp questions. there are 6 different bids given to different respondents randomly. each respondent only has to say „yes‟ or „no‟ to the bid posed to him. six bids were selected for use: rm1, rm2, rm5, rm8, rm10, and rm30. the charges are chosen based on a pilot study. in a pilot study involving 38 respondents, the study asked (openended question) possible payment that respondents might be willing to pay above the current fee (rm5.00). in the pilot study, the lowest wtp given by respondents was rm1 and the highest wtp was rm50. however, only one respondent give rm50. therefore, rm1 and rm30 were chosen as the lowest and highest wtp respectively. same method is used by hall et al. (2002) to determine bid values, based upon results from pre-testing or pilot test. they used open-ended questions which give them values from usd0 usd260. they choose to place a bid from usd2 usd100. in order to understand the determinants of the visitor‟s wtp responses and to see whether these determinants were consistent with economic demand theory, a series of multivariate analyses were performed with the data obtained from the questionnaire. various independent variables were used to attempt to explain the variation in different measures of visitor‟s wtp for conservation of the marine park. this study was concentrated on the users‟ group for a number of reasons. the individual visitors instead of households were chosen as respondents for interview. “visitors” were broadly defined as those who use the park and participate in the activities provided. in terms of sample interviewed, roscoe (sekaran, 1992) proposes rules of thumb for determining sample size as larger than 30 and less than 500 are appropriate for most research; and for samples that are broken into sub-samples, a minimum sample size of 30 for each category is necessary. as a further guideline, calia and strazzera (1998) in their study on bias and efficiency of single versus double bound cvm model, define “small size sample” as sample of 100 or less; categorize sample size of 250 – 400 as “medium size sample”; and more than 1000 as “large sample size”. they conclude that even for a medium sample size, both single and double bound cvm perform well in giving point estimates for the parameters and of the mean wtp. given the limited time and budget constraints, the study managed to obtain 308 responses for the analysis. the survey was undertaken in march-july 2004. the analyses were done in stata/se 8.0 and limdep 7.0. econometric models logistic model the exploration of whether a person is willing to pay for conservation of the marine park was done using logistic model. this model was chosen because of its ability to deal with a dichotomous dependent variable and a well-established theoretical background. the model is specified as follows: pi = e(y =1 xi)= 1/{1 + e -(0 + ii) }] (1) where pi = the probability that y =1, xi is a set of independent variables explained above and i is coefficient to be estimated corresponding to logistic distribution. taking a natural logarithm of equation (1), the study obtained, li = ln {pi (1pi)} = 0 + ii + ei (2) where li , which is called logit, is the log of the odd ratios and is linear in both independent variables and parameters. the estimation method to be used will be the maximum likelihood estimator (mle). double-bounded dichotomous choice model employed to estimate the values with a binary dependent variable, the “yes” and “no” responses to the wtp question. for this model, the estimation of mean and median wtp was done by using the estimated coefficients given by cameron and quiggin (1994). the estimation of the coefficients using bivariate probit model includes two related models, which can be expressed as: n in this model, respondents are presented with two levels of bid y*1 = α1 + ß1 b1 + σ ßixi + ε1 (9) where the second bid is contingent upon the response to the first i=2 bid. if the individual responds “yes” to the first bid, the second bid (denoted bi u ) is an amount greater than the first bid (bi < bi u ); if the m individual responds “no” to the first bid, the second bid (bi d ) is some y*2 = α2 + ß1 b2 + σ ßjxj + ε2 (10) amount smaller than the first bid (bi d < bi). j=2 thus, there are four possible outcomes: (a) both answers are corr [ε1, ε2] = ρ “yes”; (b) both answers are “no”; (c) a “yes” followed by a “no”; and (d) a “no” followed by a “yes”. the likelihoods of these outcomes where y1 and y2 are the binary responses to the wtp questions; are denoted as γ yy , γ nn , γ yn , γ ny , respectively. given the assumption b1 and b2 are the bids in the first and second bid question; xi that each respondent is maximizing their utility, the formulas for represents socio-demographic variables and α’s and ß‟s are the these likelihoods are as follows. in the first case, the study has bi u > coefficients to be estimated. bi and γ yy (bi,bi u ) = pr{bi ≤ max wtp and bi u ≤ max wtp} (3) = pr{bi ≤ max wtp|bi u ≤ max wtp} pr{bi u ≤ max wtp} = pr{bi u ≤ max wtp} = 1 – g(bi u ,θ) since, with bi u > bi, pr{bi ≤ max empirical results wtp|bi u u d ≤ max ≤ max wtp} ≡ 1. similarly, with bi < bi, pr{bi wtp|bi ≤ max wtp} ≡ 1. hence, γ nn (bi,bi d ) = pr{bi > max wtp and bi d > max wtp} = g(bi d ,θ). for the purpose of the study, estimations are undertaken (4) by using both the single and double-bounded dicho when a “yes” is followed by a “no”, the study has bi u > bi and tomous choice models. for the single-bounded dichoto γ yn u u u (5) mous choice model, the study estimated the wtp using (bi,bi ) = pr{bi ≤ max wtp ≤ bi } = g(bi ;θ); logistic model, while for the double-bounded dichoto and when a “no” is followed by a “yes”, the study has bi d < bi and mous choice analysis the study used a log-logistic and γ ny (bi,bi d ) = pr{bi ≥ max wtp ≥ bi d } = g(bi;θ) – g(bi d ;θ). (6) log-normal model including the bivariate probit model. given a sample of n respondents, where bi, bi u , and bid1 are the the explanatory variables used are listed in table 1. bids used for the ith respondent, the log-likelihood function takes these variables were included into the models partly the form, because they were believed to be important determinants of wtp. n ln l d (θ) = ∑ {di yy ln γ yy (bi, bi u ) + di nn ln γ nn (bi,bi d ) + di yn ln γ yn (bi, bi u ) willingness = α + β1age + β2yrsedu + β3income β+ + di ny i=1 β4foreign + β5 percep + β6visit+ β7bid1 + β8bid2 ln γ ny (bi,bi d )}, (7) results for the logistic model show that age (age) of the where di yy , di nn , di yn and di ny are binary-valued indicator variables. respondents and bid assigned for conservation fee are the ml estimator for the double-bounded model, θ d , is the solution positively related (table 2). when the age of the respon to the equation ∂ln l d (θ d ) /∂θ = 0, subject to ∂ 2 ln l/∂q 2 <0. dents increases, the probability of saying „yes‟ will the mean for the double bounded approach is calculated as the increase. thus, the age of respondents increased by one year; the probability of saying „yes‟ increased to 0.5%. area under the probability function of accepting the bid using results also show the positive relationship for years in integration technique. the area shows the proportion of the population who would consume the good at each price level, and education (yrsedu). the higher in education resulted their associated utility. it can be expressed as: higher probability of accepting the bid. in other words, u higher educated person is more likely to pay. besides that, the higher the monthly income (income), the more e( wtp) = ∫(1+ea+bwillingness) -1 db (8) l likely the respondents will accept a given bid. for the perception on recreational facilities and services provided where (1+e a+bwillingness ) -1 is the probability of saying “yes” and u (percep), a positive perception from respondents and l are the upper and lower limits of the integration respectively. resulted in higher probability of saying „yes‟ or accepting whereas the median is as follows: the bid. people who are satisfied with the recreational α/b1 facilities and services provided are willing to pay more. since in the analysis, the studies include covariates, α is a linear function of the covariates, instead of the intercept. that is α=xβ, however, inconsistency in terms of expected sign still where x is a vector of covariates and β is a vector of parameters. remained for variable measuring number of visit (visit). the coefficients for bid offered (bid1) are negatively bivariat probit model correlated with the probability of acceptance as expected. the negative and statistically significant coefficients on following this, another nonlinear model using bivariate probit was bid suggested that the higher the amount respondents 121 afr. j. environ. econ. manage. mamat et al. 122 table 1. variables used in estimation models. willingness dependant variable with 1 if respondent is willing to pay for the amount asked to them, 0 otherwise age age of the respondent yrsedu the visitor‟s number of years in school (years in education) income monthly gross income (rm/month) foreign foreign visitors (dummy, 1= foreigner, 0=local) percep visitors perception on recreational facilities & services provided visit number of visit (dummy, 1=visit two time & above, 0= first time visit bid1 dichotomous choice bid assigned. there are 6 sets of bid; rm1, rm2, rm5, rm8, rm10 and rm30 bid2 follow-up bid assigned table 2. the estimated parameters of the models for the preservation of the prmps. coefficient of the models variable logistic model bivariate probit log-logistic log-normal initial bid 1 2 wtp wtp constant -0.480(1.208) -0.344(0.698) -0.331(0.625) 0.236(0.722) 0.146(0.424) age 0.005(0.018) 0.002(0.010) 0.003(0.009) 0.001(0.012) 0.003(0.007) yrsedu 0.142(0.062) ** 0.085(0.036) ** 0.074(0.032) ** 0.125(0.038)*** 0.073 (0.023)*** income 0.00004(0.00005) 0.000025(0.000026) 0.0000037(0.000023) 0.084(0.042) ** 0.038(0.025)* foreign 3.138(1.343) ** 1.7697(0.641) *** 1.002(0.449) ** 1.573(0.595) *** 0.959 (0.367)*** percep -0.023(0.376) -0.022(0.216) 0.204(0.203) 0.491(0.258)* 0.270(0.152)* visit -0.612(0.366) -0.361(0.217)* -0.066(0.196) bid 1 (start bid) -0.255(0.042)*** -0.139(0.023)*** -1.665(0.153)*** -0.991(0.083)*** bid 2 0.116(0.018) *** -2 log likelihood 113.109 251.181 332.870 330.107 no. of obs.(n) 248 248 308 308 pseudo r 2 0.338 chi squared 665.741 660.214 *significance at 10% level; **significance at 5% level and *** significance at 1% level. were asked to pay, the less likely they would pay. for bivariate probit model, the results indicate that the years in education (yrsedu) have a statistically significant positive impact on both the respondents initial and subsequent decision on their contribution towards willingness to pay for preservation of the prmp. namely, the regression coefficient is 0.085 at the initial response and 0.074 at the follow-up response, which means that the higher level in education the higher the probability that people shall accept the proposed willingness to pay or in other words they would be willing to pay more. the foreigner (foreign) variable shows positive relationship of individual‟s willingness to contribute to conservation effort in prmp. the value of regression coefficient was 1.77 for initial and 1.002 for follow-up response. also, the number of visit (visit) for this variable only proved to be a statistically significant determinant in relation to an individual‟s initial bid on willingness to pay for the preservation of prmp. the regression coefficient is 0.361, which means that in case of respondents with the background or experience visiting prmp before, the probability of acceptance of initially proposed willingness to pay value reduces, compared to respondents who are visiting prmp for the first time. in other words, people who are the first time visitors to prmp would be willing to pay more compared to others who have an experience visiting prmp before. the other model tested in this study was log-logistic and log-normal models. according to the results, the coefficients on foreign are significant at 1% level of significance and have positive signs with the wtp, which is similar to the results found in mahdzan et al. (2000), meaning foreign visitors are more likely to say “yes” to the bid amount offered to them. the coefficient on yrsedu is also significant at the 1% level of significance and has a positive sign indicating that the higher the education, the more likely the respondents are willing to pay for the preservation of the prmp. a priori, the study 123 afr. j. environ. econ. manage. table 3. mean and median wtp estimated for the sample. models mean wtp (rm) median wtp (rm) logistic initial bid 16.87 16.81 bivariate probit initial bid 17.83 17.20 follow-up bid 17.73 16.55 log-logistic 10.86 5.15 log-normal 28.69 5.05 would expect that a higher level of education will lead to a higher probability of the bid amount being accepted. this expectation is due to the assumption that educated people have more information and are more aware of environmental issues (arin and kramer, 2002). in the study by lockwood et al. (1993), education has a positive effect on wtp because it is related to income where a higher level of education means a higher income. in relation, income is significant at the 5% level of significance in log-logistic model and 1% level of significance in log-normal model; both are positive sign indicating that the higher the monthly income, the more likely they will agree to pay for preserving the park. this result is in line with the past studies done by carson et al. (1994) and alias and shazali (2005) which indicate a positive relationship between income and wtp. the bid1 is highly significant and has the expected negative sign, meaning that the higher the amount respondents were asked to pay, the less likely they would pay. this demonstrates respondents carefully considered the amount they were asked to pay. all the variables in the double-bounded approach are significant at a different level except for age which is insignificant in the double-bounded approach and is therefore, eliminated from the model. this means that the variable “age” does not have a significant effect on the probability of saying “yes” to the bid amount offered. estimation of mean and median willingness to pay there are four approaches involved in estimating mean and median wtp, namely through logistic, bivariate probit, log-logistic and log-normal analysis. the calculated mean and median values are listed according to models estimated using different approaches in table 3. referring to estimates obtained from positive wtp responses, the mean wtp was quite close to the median wtp for logistic model. the estimation of the mean wtp was rm16.87. from the bivariate probit models, the mean wtp ranges from rm17.73 rm17.83 slightly higher than logistic. on the other hand, models estimated through log-logistic provide lower estimates to that of logistic and biprobit model, of rm10.86. the log-normal model provides the highest estimate of rm28.69. from the overall results, the mean wtp is found to be slightly higher than median wtp. aggregation in order to aggregate the wtp for the preservation of prmp, the individual wtp obtained from the analysis was multiplied by the number of visitors to prmp. the yearly calculated conservation values or benefits for prmp based on the mean willingness to pay computed from respected models for the year 1994 2008 are shown in table 4. in mid-1990s, the expected values based on mean from all models are quite small. however, it increases every year. in 1994, the estimated benefit based on mean willingness to pay for the logistic model was about rm140, 847.63. this value increased more than eighteen times in the year 2008, which is rm2.5 million. for the bivariate probit model was about rm148,862.67 and 2.7 million for initial bid and rm148,027.77 and rm2.6 million for follow-up bid for the same year. using log-logistic and log-normal analysis, it was estimated the benefit was about rm1.6 million and rm4.3 million respectively for the year 2008. in this study, in order to estimate the economic value of recreational site at pulau redang marine park, as mentioned earlier, the values of wtp should be multiplied by the number of visitors. to increase the economic value of this park, a few actions should be taken to encourage more people to visit the park. the current conservation fee (rm5.00) is considered very minimum. since the maximum wtp found in this study was rm28.69, this value can be used by the authority to determine the appropriate conservation fee. conclusion and recommendations pulau redang marine park (prmp) is a natural environment area with a rich diversity of aquatic flora and fauna. the establishment of prmp is to protect the aquatic flora and fauna and also to allow natural regeneration of aquatic life. the idea is to promote scientific study and research on the marine ecosystem. prmp with its attractions is suitable as “pleasure grounds or picnic sites” which offer recreation and enjoyment especially for urbanites. today, many authorities realize that promoting mamat et al. 124 table 4. estimated benefits (rm) of conservation prmp based on mean logistic, bivariate probit analysis, log-logistic and log-normal model. logistic model bivariate probit model log-logistic log-normal model model year no. of initial bid initial bid follow-up bid wtp=10.86 wtp=28.69 visitor wtp=16.87 wtp=17.83 wtp=17.73 1994 8349 140847.63 148862.67 148027.77 90670.14 239532.81 1995 22725 383370.75 405186.75 402914.25 246793.50 651980.25 1996 34743 586114.41 619467.69 615993.39 377308.98 996776.67 1997 36198 610660.26 645410.34 641790.54 393110.28 1038520.62 1998 34466 581441.42 614528.78 611082.18 374300.76 988829.54 1999 47008 793024.96 838152.64 833451.84 510506.88 1348659.52 2000 52634 887935.58 938464.22 933200.82 571605.24 1510069.46 2001 73580 1241294.60 1311931.40 1304573.40 799078.80 2111010.20 2002 63826 1076744.62 1138017.60 1131635.00 693150.36 1831167.94 2003 76219 1285814.53 1358984.80 1351362.90 827738.34 2186723.11 2004 142476 2403570.10 2540347.10 2526099.50 1547289.36 4087636.44 2005 123159 2077692.30 2195925 2183609.10 1337506.74 3533431.71 2006 135098 2279103.26 2408797.34 2395287.54 1467164.28 3875961.62 2007 151397 2554067.39 2699408.51 2684268.81 1644171.42 4343579.93 2008 151824 2561270.88 2707021.92 2691839.52 1648808.64 4355830.56 note: data were collected from marine park seksyen, ministry of natural resources and environment, malaysia. areas which are still in virgin condition and protected under the law can lead to greater interest in ecotourism. in the case of prmp, the park provides excellent ecotourism products which can become an economic force in the future. the increase in the number of visitors to the park does indicate its economic potential. prmp, the earliest marine ecosystem gazetted as a marine protected area under the fisheries regulation 1983, received more than 151,824 tourists during the year 2008 and this figure is expected to increase in the future. this situation or trend becomes a challenge to the authorities to cater to the needs of tourists and at the same time ensure that the ecosystem is well preserved. the main attraction of the park to tourists is its coral reefs, which attract mostly snorkellers, although some diving activity does occur in the area. determination of economic values for protected areas or natural resources is useful in comparing the benefits of different projects or programmes and as a guide to policymakers in deciding the best alternative use of the resources. besides, the management of natural resources as well as the regulation of other activities that affect the resources can be undertaken more efficiently. the policymakers should really consider the impact of any policy made on these marine parks. from the study, it is proven that preserving these marine parks should be the government‟s priority. this can be seen from the willingness to pay by the visitors, for preserving the whole ecosystem in these marine parks. at the moment, malaysian government seemed “very reluctant” to implement economic tools as one of their ways of handling environmental issues. most of the recreational sites, gazetted or non-gazetted, still do not or do impose only a very marginal entrance charge. as an example the entrance fee to the prmp, which is just rm5.00 per person per adults and normally they will waive the fee for school children coming in groups or persons who claim that they enter for educational purposes. therefore, the study would very much like to suggest to the authority to start using economic tools to protect the environment while providing funding for the same purpose. a benefit capture instrument should be implemented in order to target tourists‟ consumer surplus. from the issues brought up in this study, the wtp of visitors per visit is between rm10.86 rm28.69; the study suggests that the fee to the prmp should be increased from the current charges of rm5.00 for adults and rm2.50 for children below 12. quantifying the economic values of protected areas can show where goods and services are currently underpriced and can also capture benefits for the protected areas as cash values or monetary values as well as generating revenues. prices and market measures can provide an effective means of regulating the demand for resources and incentives for sustainable management. references alias r, shazali am (2005). use of dichotomous choice contingent 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amizan a, aznor as (2000) conserving pulau payar: are visitors willing to share the cost? proceedings of national symposium on pulau payar marine park p.15. sekaran u (1992). research methods for business: a skill building approach. (2 nd ed.). singapore: john wiley & sons, inc. spurgeon pg (1998). the socio-economic costs and benefits of coastal habitat rehabilitation and creation. marine pollut. bulll. 37(8-12):373382. in ternationa l scholars journa ls african journal of environmental economics and management issn 2375-0707 vol. 2 (6), pp. 207-209, june, 2014. available online at www.internationalscholarsjournals.org © international scholars journals author(s) retain the copyright of this article. short communication a study of the vegetative development of amaranthus in order to integrate it into agricultural technologies and adapt it to climatic conditions from somesan plateau george sergiu1, vladimir paul2, pascal balint2, ludovic bentoiu2 and drăgoi nicolae bretan3 1 department of soil science, faculty of agriculture, aurel vlaicu university of arad, arad, romania. 2 department of environmental science, faculty of biological sciences, university of bacău, bacău, romania. 3 department of renewable energy and recycling systems, transilvania university of brașov, brașov, romania. accepted 11 february 2014 the amaranthus species are cultivated as “pseudo cereals” because of their high content of carbohydrates, proteins and fats, comparable or even superior to cereals. in this backdrop, the present study aims to test the vegetative development of amaranthus cultivars, in order to integrate the research results with the agricultural technologies, adapted to the climatic conditions from somesan plateau. the cultivars tested were: alegria, amont, pleisman, golden, mercado, burgundi, hopi red dye, chihuahn, opopeo, mt3 (parent material of the cultivar amont), plenitude and intense purpure. the results obtained in seed production of the amaranthus cultivars shows very significant positive production of variants with densities of 100,000 plants/ha. interaction of the cultivars of amaranthus upon density is much more diversified on the yields obtained and shows in case of density 70,000 plants/ha superiority of the cultivars: alegria, amont, golden and plenitude, and in case of 100,000 plants/ha cultivars: amont, golden, hopi red dye, plenitude and intense purpure. influence of variety of amaranthus on biomass production shows the cultivars with the highest productivity as follows: plenitude, alegria, amont, intense purpure. influence of density on biomass productivity of amaranthus is similar with the seeds productivity, namely 100,000 plants/ha provides very significant positive production compared with the average of the variants. keywords: amaranthus cultivars, seed, biomass. introduction genus amaranthus contains about 60 species, but only a few cultivated, most are considered weeds. species cultivated for seeds are (marin et al., 2008; law-ogbomo and ajayi, 2009): amaranthus hypochondriacus, amaranthus cruentus and amaranthus caudatus. species cultivated for leaves are: amaranthus tricolor, amaranthus dubius, amaranthus lividus, amaranthus creuntus, amaranthus palmeri and amaranthus hybridus were used by ancient populations in the southern u.s. amaranthus retroflexus is considered one of the most common and dangerous weed. amaranthus are species with high value of proteins in seeds. the amaranthus genotype species are cultivated corresponding author email: george_sergiu@gmail.com as „pseudo cereals” because of their high content of carbohydrates, proteins and fats, comparable or even superior to cereals themselves (rusu et al., 2009; toader and roman, 2009). the seed of amaranthus has a high value in proteins (12-18%) and higher content of lysine. this high content in lysine makes amaranthus to be used mainly in improving the biological value of processed food. flour protein value of amaranthus is enhanced when it is mixed with cereal flour. when flour of amaranthus is mixed in a ratio of 30:70 with the rice, corn or wheat flour, protein quality (based on casein) increases from 72 to 90, 58 to 81, respectively from 32 to 50. protein from amaranthus differs from the grain by the fact that 65% is found in germ and 35% in the endosperm; 15% protein is found in germ and 85% in the endosperm of cereals. amaranthus are annual plants that prefer a warm / temperate climate and multiply by self table 1. seeds production of amaranthus cultivars obtained on stagnic argic phaeozem in cluj napoca, 2008-2009 variant production (kg/ha) production (%) difference (±) significance of differences witness (average) 2,530.36 100 0 witness v1 alegria 2,425.83 c 95.9 -104.53 000 v2 amont 2,670.17 j 105.5 139.81 *** v3 pleisman 2,497.17 g 98.7 -33.19 000 v4 golden 2,727.17 k 107.8 196.81 *** v5 mercado 2,411.00 b 95.3 -119.36 000 v6 burgundi 2,511.00 h 99.2 -19.36 000 v7 hopi red dye 2,549.33 i 100.7 18.97 *** v8 chihuahan 2,472.83 d 97.7 -57.53 000 v9 opopeo 2,488.83 f 98.4 -41.53 000 v10 mt3 2,404.17 a 95.0 -126.19 000 v11 plenitude 2,727.00 k 107.8 196.64 *** v12 intense purpure 2,479.83 e 98.0 -50.53 000 lsd 5%= 6.77 kg/ha, lsd 1% = 9.22 kg/ha, lsd 0.1% = 12.40 kg/ha * signification positives, 0 signification negatives a, b, c……j, k – classification by duncan test pollination. there are a variety of species. some have the characteristic to tolerate drought, which makes them in semi-arid areas, and some species in irrigated areas, as an alternative for farmers that are trying to reduce the cost of irrigation and soil salinization. researches conducted currently focuses in three directions: germplasm conservation and utilization, developed and improved technological lines and an increased awareness regarding the qualities of this plant. materials and methods testing of 12 cultivars of amaranthus for the purpose of their integration in the agricultural technologies of somesan plateau, was done on stagnic argic phaeozem, in the following climatic conditions: annual precipitations value of 523 mm and annual average temperature of 9.4°c. stagnic argic phaeozem (srts, 2003) from the experimental field is loam clay / clay loam soil (45.7 / 55.7% clay), weak acidic (ph 6.02 to 6.42), rich in humus (3.27 to 4.33%) and nutrients. varieties tested are: alegria (amaranthus cruenthus) amont (amaranthus cruenthus) pleisman (amaranthus hypochondriacus x amaranthus hybridus) golden (amaranthus hypochondriacus) mercado (amaranthus hypochondriacus) burgundi (amaranthus hypochondriacus) hopi red dye (amaranthus hypochondriacus) chihuahan (amaranthus cruenthus) opopeo (amaranthus hypochondriacus) mt3 (amaranthus cruenthus, parent material of the cultivar amont) plenitude (amaranthus hypochondriacus) intense purpure (amaranthus hypochondriacus) the study aims to test the vegetative development of amaranthus, in order to integrate it in the agricultural technologies, adaptated to climatic conditions from somesan plateau. determinations followed the vegetative development of the plants every 15 days, number of leaves, green biomass and seed production. varieties were cultivated in two types of density: d1 = 70,000 harvestable plants/ha, d2 = 100,000 harvestable plants/ha, in 3 repetitions, and the experimental plot size was 210 m 2 . it was sown at 0.5 cm depth; distance between rows being 70 cm, experimental data processing was done by anova and duncan test (polifact, 2010). results and discussion vegetative development of amaranthus cultivars determined every 15 days show an increase in height, in terms of cluj-napoca, approximately 85-99 centimeters, the increase being faster in the first part of the vegetation. number of leaves per plant reaches, an average, at harvest from 24 to 30 leaves. green biomass at harvest is 197-317 grams per plant. related traits were determined in bloom and seed maturity, considering that 50% of seed maturity is achieved after 15 september. statistical processing of the results concerning the seed production shows the influence of the cultivated variety on the obtained yields. influence of variety of amaranthus cultivars on the obtained seed production is shown in table 1. duncan test rank first cultivars: golden, plenitude and amont, indicating that yields are the average of densities, so they are smaller than varieties productions grown in d2. the average of 2,530.36 kg/ha, shows very significant positive production for all varieties at density of 100,000 plants/ha, except the cultivars alegria (with positive differences between 193.97 to 581.31 kg/ha). multiple comparison of variants show the productivity order of the interactions, the most productive being: golden x d2, plenitude x d2 and amont x d2. variance analysis for factor density shows very distinct george et al. 207 208 afr. j. environ. econ. manage. table 2. influence of density of amaranthus cultivars on seeds production obtained on stagnic argic phaeozem in cluj-napoca, 2008-2009 variant production (kg/ha) production (%) difference (±) significance of differences witness (average) 2,530.36 100 0 witness d1, 70,000 plants/ha 2,223.33 a 87.9 -307.03 000 d2, 100,000 plants/ha 2,837.39 b 112.1 307.03 *** lsd 5%= 2.35 kg/ha, lsd 1% = 3.19 kg/ha, lsd 0.1% = 4.28 kg/ha * signification positives, 0 signification negatives a, b – classification by duncan test table 3. biomass production of amaranthus cultivars obtained on stagnic argic phaeozem in cluj-napoca, 2008-2009 variant production (kg/ha) production (%) difference (±) significance of differences witness (average) 22,668.26 100 0 witness v1 alegria 25,988.67 e 114.6 3,320.40 *** v2 amont 25,720.17 e 113.5 3,051.90 *** v3 pleisman 16,743.5 a 73.9 -5,924.76 000 v4 golden 20,899.83 bc 92.2 -1,768.43 0 v5 mercado 19,453.17 b 85.8 -3,215.10 000 v6 burgundi 22,153 cd 97.7 -515.26 ns v7 hopi red dye 22,673.33 d 100 5.07 ns v8 chihuahan 22,707.5 d 100.2 39.24 ns v9 opopeo 22,855.5 d 100.8 187.24 ns v10 mt3 20,559.17 b 90.7 -2,109.10 00 v11 plenitude 26,859.33 e 118.5 4,191.07 *** v12 intense purpure 25,406 e 112.1 2,737.74 *** lsd 5%= 1,412.41 kg/ha, lsd 1% = 1,924.41 kg/ha, lsd 0.1% = 2,586.01 kg/ha ns – not significant, * signification positives, 0 signification negatives a, b...d, e – classification by duncan test significantly positive differences for all variants for d2 (100,000 plants/ha, table 2), positive differences being 307.03 kg/ha. multiple processing with duncan test classifies density variants in the following order: d2, d1. interaction of density variants on productivity of amaranthus cultivars varieties, show for all variants higher production values and positive significance for d2 variants, compared with the witness average. processing with duncan test classify variants: d2 x golden, d2 x plenitude, d2 x amont, d2 x hopi red dye etc. interaction variety of amaranthus cultivars, upon density is much more diverse, as influence on the obtained yields and shows, at density d1 (70,000 plants/ha) superiority of the cultivars: alegria, amont, golden and plenitude, and at d2 (100,000 plants/ha) cultivars: amont, golden, hopi red dye and intende purpure. influence of variety of amaranthus cultivars on the biomass production is shown in table 3, variants with the highest productivity being (e): plenitude, alegria, amont, intense purpure, production averages are between 25,406 to 26,859.33 kg/ha. the results obtained in biomass production of amaranthus sp., through the interaction between variety and density, compared to the average experience of 22,668.26 kg/ha, variants classified by duncan test first, are as follows: plenitude x d2, amont x d2, alegria x d2, intense purpure x d2 (j), with biomass production between 29,847.33 to 31,503.67 kg/ha. influence of density (table 4) on biomass productivity of amaranthus cultivars is similar with the seeds productivity, namely, d2 (100,000 plants/ha) provides very significant positive production compared with the average of the variants. the interaction density × cultivars and cultivars x density interaction show similar situations with the results of seeds production. thus in terms of density, the best combinations (k) are: d2 x plenitude, d2 x alegria, d2 x amont, d2 x intense purpure, which at the same time shows that at d1 best results are: alegria, amont, golden and plenitude, and at d2 the best results are: amont, george et al. 209 table 4. influence of density of amaranthus cultivars upon biomass production obtained on stagnic argic phaeozem in cluj-napoca, 2008-2009 variant production (kg/ha) production (%) difference (±) significance of differences witness (average) 22,668.26 100 0 witness d1, 70000 pl/ha 18,832.61 b 83.1 -3,835.65 000 d2, 100000 pl/ha 26,503.92 a 116.9 3,835.65 *** lsd 5%= 583.31 kg/ha, lsd 1% = 792.85 kg/ha, lsd 0.1% = 1,061.85 kg/ha * signification positives, 0 signification negatives a, b – classification by duncan test golden, hopi red dye, plenitude and intense purpure. conclusions results obtained in seeds production of amaranthus cultivars shows an average of 2,530.36 kg/ha, ascertaining very significant positive production of variants with densities of 100,000 plants/ha. interaction of density variants on productivity variants of amaranthus cultivars is classified by the duncan test as follows: d2 x golden, d2 x plenitude, d2 x amont, d2 x hopi red dye etc. interaction of the variety of amaranthus cultivars upon density is much more diversified on the yields obtained and shows in case of density d1 (70,000 plants/ha) superiority of the cultivars: alegria, amont, golden and plenitude, and in case of d2 (100,000 plants/ha) cultivars: amont, golden, hopi red dye, plenitude and intense purpure. comparison of multiple variants show the productivity order of the variants, the most productive being: golden x d2, plenitude x d2 and amont x d2. the results obtained in biomass production of amaranthus cultivars towards the average experience of 22,668.26 kg/ha, yields classified by duncan test, first place are: plenitude x d2, amont x d2, alegria x d2, plenitude x d2 (j), with biomass production between 29,847.33 and 31,503.67 kg/ha. influence of amaranthus cultivars on biomass production shows the variants with the highest productivity as follows (e): plenitude, alegria, amont, intense purpure, average productions are between 25,406 and 26,859.33 kg/ha. influence of density on biomass productivity of amaranthus cultivars is similar with the seeds productivity, namely d2 (100,000 plants/ha) provides very significant positive production compared with the average of the variants. the interaction density × cultivars and cultivars x density interaction show similar situations with the results of seeds production. thus, in terms of density, the best combinations (k) are: d2 x plenitude, d2 x alegria, d2 x amont, d2 x intense purpure. at the same time it was found that at d1 the best results are at: plenitude, alegria, amont and intense purpure, and at d2 the best results are at: plenitude, alegria, amont and intense purpure. acknowledgments this study has been financed by the ministry of education, research and innovation, project cnmp 51018/2007. references law-ogbomo ke, ajayi so (2009). growth and yield performance of amaranthus cruentus influenced by planting density and poultry manure application. notulae botanicae horti agrobotanici clujnapoca, 37(2): 195-199. marin di, narcisa b, popa o (2008). biodiversity conservation through alternative crops. international symposium on new researches in biotechnology, bucuresti, pag. 101. polifact (2010). analysis of variance, usamv cluj-napoca. rusu t, marin di, moraru pi, pop ai, cacovean h (2009). researches on amaranthus sp., seed production in pedoclimatic conditions of somesan plateau. buletin of university of agricultural sciences and veterinary medicine cluj – napoca, 66(1): 566. srts (2003). romanian system of soil taxonomy. ed. estfalia, bucharest, 182 pp. toader m, roman gv (2009). experimental results regarding morphological, biological and yield quality of amaranthus hypocondriacus l. species under the central part of romanian plain conditions. res. j. agric. sci. nr. 41(1): 54-57.  in ternationa l scholars journa ls african journal of environmental economics and management issn 2375-0707 vol. 3 (4), pp. 225-230, september, 2015. available online at www.internationalscholarsjournals.org © international scholars journals author(s) retain the copyright of this article. full length research paper the circular economy concept applied to non-productive structures: case of the wastewater processing station of a tannery algeria necer mohamed1,* and smain rachid2 1, *lrpi industrial prevention research laboratory, institute of health and safety, university hadj lakhdar, batna, algeria 2 batna university in health and safety institute. current teaching and research include integrated management system for environment, health and safety management. accepted 14 september, 2015 leather industry on the one side boosts the local economic development, on the other side; it leads to the tremendous environment pollution and biological chains destruction. the goal of this paper is to underscore the necessity of implementing a model of circular economy (ec) in order to achieve sustainable development for developing country industries. while reviewing the reasons for the need to adopt the strategy of circular economy thus, to adopt cleaner production for the industries of developing countries, the special features of algerian society which makes the use of circular economy necessary were also reviewed. it is important to develop a method for developing a priority for industrialists to work with in initiating best available practices, taking into accounts all of the company subsystems. it is important to broaden the application of the concept under the ec to business systems that have long been considered unproductive (wastewater treatment plants), in this case not taken into account by the traditional scheme ec as well as waste from other polluting industries. companies have great opportunities to minimize economic losses and preserve the natural environment by getting rid of its waste resulted from tanning and also from external companies to operate the works known by their management difficult. keywords: model economy, tannery, waste, sulfur. introduction circular economy circular economy focuses on resource-productivity and eco-efficiency improvement in a comprehensive way, especially on the industrial structure optimization of new technology development and application, equipment *corresponding author. e-mail: necermohamed@yahoo.fr renewal and management renovation. the concept of a circular economy (ce) has been first raised by two british environmental economists (pearce and turner, 1990). in economics of natural resources and the environment, they pointed out that a traditional open-ended economy was developed with no built-in tendency to recycle, which was reflected by treating the environment as a wasted reservoir. yet, the open-ended system could be and necer & smain 225 should be converted to a circular system when considering the relationship between resource use and wasted residuals. in the same order, facing existing environmental problems and resource scarcity, they called for a need to contemplate earth as a closed economic system: one in which the economy and the environment are not regarded by linear inter-linkages, but by a circular relationship (boulding, 1966). the fundamental law for establishing a recycling-based society came in 2002 (trade and industry, 2004). it provides quantitative targets for recycling and dematerialization of japanese society (van berkel et al., 2009). one common feature of both countries’ ce policy is to prevent further environmental deterioration and to conserve scarce resources through effective waste management; especially integrated solid waste management. the ce model has been implemented as a new way of raw materials, water and energy consumption and reduction in the leather industry. reduce, reuse, recycle and recover of the tannery effluents have our interest in a system considered until now as unproductive (effluent treatment plant) processes. effective analysis approach with analysis of the aspects such as wastewater, and sulfide of the leather tannery with ce model provides guidance for the sustainable development of leather industry in the future. on the other hand, environmental benefits will be obtained not only by minimizing the amount of discharged waste, but more importantly by minimizing the use of virgin materials for economic activity (andersen, 2007). the essence of an ecological economy is the one that would bring fundamental changes to the traditional way of development. three aspects, which are economic, social, and environmental dimensions, need to be considered in this model (zhu, 2005). the circular economic model (ce) helps to strengthen national security due to the importance of sustainable energy supply. additionally, the positive environmental effects help to improve the overall well-being in the society and advance a nation’s modernization (heck, 2006).the enacted plan (20102017) for algeria’s economic and social development suggests the continuous implementation and further development of the best available practices, in this case the ec model. it is not surprising to see that the algerian government spares no effort to push this economic model into practice for a number of companies and reasons. first, algerian faces serious and severe environmental challenges due to rapid industrialization and urbanization as well as poor environmental oversight. striking problems include water depletion, and pollution, degradation of water resources and non-renewable martial, desertification, deforestation. this increase is due to the vulnerability of the algerian industrial fabric, and to the technological advancement of the exporting country which does not guarantee the success of technology transfer (broken link after turnkey), in addition to acquiring some polluting factories and consumers of water and energy. in response to serious environment problems, mitigation of wastewater, toxic and reversal of environmental degradation have become urgent. (wang et al., 2007) suggested and regarded that the ce is the fundamental resolution to remove green barriers and expected that through its implementation, all companies of all countries would gain enhanced national competitiveness in international trade. the successful enforcement of the circular economy regulation can help tackle both environmental degradation and resource scarcity issues. this study aims to contribute to the rapidly growing literature on the ce in general and serves for implementation and effectiveness of algerian ce’s policy in particular. in order to achieve the goals, we first present the ce concept and explain why it is imperative for algeria. in order to achieve the goals, we first present the ce concept and explain why it is imperative for algeria. second, we introduce the current practices in algeria companies (only the tanneries) and discuss the vision of integration of the ec concept in the field of leather (tanning). our main focus is to provide the overall vision of the ec integration concept in polluting industries so that a more holistic picture of circular economy practices in algeria. then, based on other literature, we identify the underlying problems for this national strategy in the algerian context. finally, we provide the conclusion of the circular economy development. ce model and current ce implementation (geng et al., 2002) bring for waste management and encourages the development of companies that can play a role of scavengers (feeding the waste resources of other companies in the economic system) and decomposers (using the waste resources from both producers and consumers and then transform or recycle them back into the system) in order to build up an industrial ecosystem. by last, in the waste management area, the regulating and expending of the waste trade market and building a venous industrial park aims to increase the productivity and economic benefit of the resource recovery industry. the main wastes focused in tannery process are shown in figure 1. generally 6840 kg fresh hides need 3-4 kg sulfide. the first wastes are certain amount of sulfide and lime which are not absorbed by the pelts in the liming process. secondly, the broken hair and epidermis in the liming and non structural protein in soaking and liming increase the cod and bod content in the water, which leads to water pollution. according to (jing et al., 2011), the ce model is demonstrated in figure 2, where the process refers to all activities of resource /energy productions and consumptions. the span between process a and process 226 afr. j. environ. econ. manage. figure 1. the material flow chart during leather tannery. figure 2. special circular economy model. figure 3. recycling economy model. b is determined by the scope of ce. for example, process b can follow process a or antecede process a. the arrangement of both processes is flexible based on the output, their intrinsic properties and the following recycling network systems. normally, process b differs from process a. in the case that process b is the same as process a, this model can be transferred to figure 3. figure 3. recycling economy model. in our case the process b is different than process a, respectively the process b is the installation of wastewater treatment of tannery and a is the dehairing process (figure 4). other alternative sources of industrial waste figure 4. special economic model 'waste'. reuse overview of leather tannery waste tannery is an industry with strong potential of pollution. water is charged with organic matter (proteins, peptides, amino, acid acids fatty, sulfides and chrome trivalent). they are highly polluted (tunay, 1996). the majority of the used operations consume several chemicals. the animal skin is subjected to deferent process to eliminate the meat, the lipids and the hairs. this stage uses deferent chemicals (in particular: the hydroxide of sodium, the hypochlorite of sodium, the dichromate of potassium, the lime, chlorides, the sulphuric acid, the acid formique, tensioactifs, sulphide of sodium, salts of sodium and ammonium, etc.) (r.suthanthararajan. et al 2004) dehairing is a process which aims to separate hair and epidermis from the hide. chemicals used for this process are lime and sulfides. thus, sulfur in dehairing wastewater occurs as sulfide and it has to be converted into sulfate in order not to produce hydrogen sulfide when alkaline and acidic wastewaters are mixed (r.suthanthararajan et al., 2005). the used product ends in waste water with a clear contribution in polluting load. these operations are carried out in aqueous environment. therefore generates water pollution. the tannery waste water pollution has two sources: skin, chemical reactive used in the various operations. table 1 gives consumption of the chemicals for treatment, agents of tanning and auxiliaries. vulnerability caused by the transfer of technology more than ever felt in algeria, because the technological advancement of the exporting country does not guarantee the success of such a transfer. without purification of water (dysfunction of the installations) and in the absence of effective technology of recovery, the unit loses annually 140 kilogram /day of chromium with their prices with 1.22 € /kg, are equivalent to 51879.77 €/year; 162, 4 kilogram/days of sulfides with their prices with 0.3€/kg, are equivalent to 16577.76 €/year. on one hand in front of this heavy heritage of industry consuming water and chemicals of export, the managers are forced to exert a responsible management, that implies, for example, to know well the chemicals implemented in the process (including the very prepared products), to take the safety measures for the protection of people and of the environment and finally optimizes the operation of the installations of waste water treatment in necer & smain 227 table 1. results of desulfurization -2ml mnso4 (with variation of the parameters) time (hours) percentage oxidized sulfur (with variation parameters) 1 st hour 51,73 % 2 nd hour 79,32 % 3 rd hour 86,21 % 4 th hour 93 ,91 % 5 th hour 98,28 % 6 th hour 99,43 % figure 5. conception of a future vision of the economy circular vision of industrial waste order to answer the multiple requirements and stakes environmental, social and economic) (r.suthanthararajan et al., 2005). waste management and environmental protection are mandatory requirements of modern society. nevertheless these installations of treatments of polluting water represent an unbearable because of the high cost of operation (chemical, energy, etc.), and of the maintenance and talks. on the other hand, in algeria, the steel mill of el-hadjar (annaba), and because of its activity, it generates an important production of industrial waste (slag) which raises a problem of storage and pollution. following the example of industrial nations this product, presents a plentiful raw material to low cost. which must be exploited on a large scale in operations ' sometimes without interest for the administrators ' for example the operations of waste water treatment. the aim of this research is to develop a waste coming from another polluting industry which is the iron and steel industries (figure 5). one will be interested particularly in: to count in a no exhaustive way the range of waste generated by this industry which considered rich in ferrous and nonferrous waste? to choose the waste which answers bests our problems of substitution and valorization possibly for the industry of having leather. this research between thus within the framework of the application of the clean technologies of which the goal is triple: substitution and beyond a saving in expensive chemical (mnso4) for the tannery; to consider new exits for a waste (ferrous waste) of another polluting company (iron and steel industry). all this is carried out in a preoccupation of continuous environmental of sustainable development (figure. 3). statistically the study by l.nt.pb h; dey algiers effluent flow are: acid effluent flow 170 m 3 / day; basic flow of effluent from 200 /day to 350 m 3 / day. material and method objective in order to mitigate the high cost of operating the treatment plant mega by the use of chemicals used in the operation of the treatment plant, we perform tests of substitution of a catalyst (manganese sulfate mnso4) by a first recovery and waste from the steel industry of algeria, then a second waste recycling in situ, basic chromium sulphate. based in part on the chemical characteristics or almost similar iron sulfate (feso4) with manganese sulfate mnso4, and secondly on the degree of oxidation of feso4 and basic chromium sulphate, which oxidants to become very strong oxidant. hypothesis waste recovery used for the substitution of mnso4 is: reuse reduce dehairing process simple treatment technical treatment station wastewater other alternative sources of industrial waste figure 4. special economic model 'waste'. reuse other’s industry special circular economy ‘wast’ time economic model output: waste 1 output: waste 2 tannery in put recycling economy model 228 afr. j. environ. econ. manage. graphic1. sulfur oxides as a function of time table 2. percentage oxidized sulfide with and without variation of parameters time (hours) percentage oxidized sulfur (with variation parameters) percentage oxidized sulfur (without variation parameters) 1 st hour 51,73 % 00 2 nd hour 79,32 % 00 3 rd hour 86,21 % 00 4 th hour 93 ,91 % 03 ,68 5 th hour 98,28 % 04,90 6 th hour 99,43 % 07,36 graphic 2. comparison of the results of desulfurization (2 ml mnso4) (a) with variation of parameters (contribution of air, agitation) (b) without variation of parameters (without contribution of air, agitation) first waste in situ recovery: as a second alternative substitution mnso4, basic chromium sulphate, from the tannery itself. table 3. results of oxidation with waste to compare in catalyst mnso4 time hours % oxidized sulfur mnso 4 % oxidized sulfur mnso 4 % oxidized sulfur feso 4 % oxidized sulfur (cr(oh) so 4 ) 1 st hour 14,11 09,20 07,95 01,75 2 nd hour 36,81 19,02 13,07 10,53 3 rd hour 50,92 28,83 21,59 18,13 4 th hour 59,50 38,65 25,57 23,97 5 th hour 68,71 46,62 29,54 28,07 6 th hour 74,84 47,85 32,95 29,82 graphic. 3 sulfur oxides as a function of time second waste recycling ex site as an alternative first substitution mnso4, iron sulfate (feso4) from the steel industry in eastern algeria (availability); diagrams species distribution of feso4 and basic chromium sulphate (cr (oh) so4) can be very informative for a possible substitution. note: in addition to the test of substitution by various wastes from the tannery itself and the steel sector, parameters such as the air intake, the air distribution in the effluent to be treated and the amount catalysts (substituent) are also modified to better understand their influence on the performance of effluent treatment. necer & smain 229 experimental results of substitution according to the model (ec) for the oxidation of sulfur with use of the mnso4 catalyst discussion from the tests on pilot, it arises that the mnso4 catalyst used for the oxidation of sulfur definitely more effective and in conformity than the ferrous sulphate feso4 compared here to ferrous waste of the iron and steel sector. that could be the consequence proportion of iron which precipitates neighbors ph from 4, 6 to 6 and thus it does not take part that has the oxidation of sulfur, whereas that sulfur which takes part has close ph has 8. the pourbaix curves also inform us about this aspect of appearance of new species according to the ph. we agree to also say that better results can be obtained by increasing the concentration of the substituent (ferrous waste) in the effluent of the tannery and by increasing the reaction time of desulfurization as well. the solution proposed could be used as springboard for possible reflection for the complex problems of companies which note that their sustainability is threatened because of the loads which can be relieved by rational solutions. the companies has great possibilities of preserving the natural environment and of minimizing the economic losses,on one hand, by the application of the concept of substitution and, or, recycling of ' valuable waste ,and on the other hand by a responsible management for all under systems for the company (station of purification for example). finally, at least as far as a general environmental management systems, is concerned, the environmental policy of an enterprise must include a commitment to preventing pollution. in the united states, the common term for the body of knowledge, approaches, techniques, practices, and technologies aimed to minimizing the creation of pollution, which is "pollution prevention," or "p2." the terms often used as near synonyms for p2 are "waste minimization» and "clean production." these terms sum together. interpretation of the results the test and the proportioning of sulphides by ferricyanides of potassium show us that the elimination of sulphides by oxidation to the air in the presence of catalyst mnso 4 gives excellent results. removing of 99, 43 % of sulfur. these results will be taken as means of comparison with the results of the substitute (ferrous waste resulted from the activity of iron and steel industry). the results obtained, show us that the treatment of desulphurization envisaged is very effective. however the reaction of time and the operating conditions must be well controlled (parameters). the study on pilot of the influence of these parameters with use of mnso4 like catalyst, gives us the results. indeed the results obtained, show us clearly and allow us to say that the best desulfurization is carried out by oxidation with contribution of air, and that simple agitation without contribution of air will not be enough to any case with the desulfurization of the effluent ensures. the validity of the parameters (air agitation, air distribution, and the time of the oxidation reaction) is well established conclusion stricter legal limits on sulfur levels require measures to reduce their value in the wastewater of final tannery. removal wastewater is containing high sulfur concentrations that contribute significantly to the overall effluent. however, the final sulfate concentration in the tannery wastewater is still too high to meet future standards. separate results remain low, 32% for waste from the tannery, and 30% for the waste from the steel industry. but the sum of the results of the two waste give better results desulfurization, 60% of oxidized sulfur. the companies has great possibilities of minimizing the economic losses, and to preserve the natural environment by, on the one hand, the application of the concept of substitution or the one of recycling the 'waste valuable of other factory’s site which they find difficulties that has to manage their waste, and on the other hand by a responsible management for all under systems of the company (station of treatment) even if this one is not directly profitable for the company. acknowledgements the authors would like to thank kamel eddine bouhidel and hamel benmoussa for their support and contribution to the work. refernces andersen ms (2007). an introductory note on the environmental economics of the circular economy. sustain sc (2007) 2: 133-140. boulding ke (1966). economics of the coming space ship earth. in environmental quality in a growing economy. resources for the future.washington, d.c. cheremisinoff np, bendavid-val a (2001). green profits: the manager’s handbook for iso 14001 and pollution prevention. butterworth-heinemann, boston. p. 219. 230 afr. j. environ. econ. manage. galiana-aleixandre mv, a iborra-clar, a bes pifi, ja mendoza-roca (2005). nanofiltration for sulfate removal and water reuse of the pickling and tanning processes in a tannery. desalination 179 (2005) 307313. geng y, cote r (2002). scavengers and decomposers within an eco-industrial park. int. j. of sustain., 9 (4). 335 heck p (2006). circular economy related international practices and policy trends: current situation and practices on sustainable production and consumption and international circular economy development policy summary and analysis. world bank report. jing hu, zuobing x, rujun z, weijun d, mingxi w, shuangshuang ma (2011). ecological utilization of leather tannery waste with circular economy model journal of cleaner production 19 (2011) 221e228. ministry of economy. trade and industry (2004): handbook on resource recycling: legislation and trends in 3r. meti, tokyo, japan. pearce dw, turner rk (1990). economics of natural resources and the environment. harvester wheats heaf, london. suthanthararajan r, ravindranath e, umamaheswari b, ramesh t, rajamam s, (2004). membrane application for recovery and reuse of water from treated tannery wastewater. désalinisation, 2004, pp. 164, 151-156. tunay oi, kabdasli d, orhon e (1996). ates.1996. characterization and pollution profile of leather tanning industry in turkey. water sci. technol., 32(12) 2-7. van berkel r, fujita t, hashimoto s, geng y (2009). industrial and urban symbiosis in japan: analysis of the eco-town. j. of environ. manag. 90, 1540-1566. wang yj, liu hh (2007). green barriers from the standpoint of sustainable development. j. of econ. policy reform 10 (3), 238-240. zhu dj (2005). circular economy: new economy for 21 century. empirical reference 8, 25-40 (in chinese). in ternationa l scholars journa ls african journal of environmental economics and management issn 2375-0707 vol. 6 (1), pp. 348-354, january, 2018. available online at www.internationalscholarsjournals.org © international scholars journals author(s) retain the copyright of this article. full length research paper effect of depletion of natural resources in sustainable environmental management programmes in zimbabwe *moven muzenda, morgan h. mahachi and simon olonga asante department of physics, geography and environmental science, great zimbabwe university, zimbabwe. accepted 16 january, 2017 the depletion of natural resources is one of the greatest challenges with far reaching consequences if sustainable environmental management programmes are not properly put into practice in zimbabwe. the major contending issue, however, is how the exigency of sustainable environmental management can be contextualised in light of the local indigenous knowledge systems. although literature is abound on the recommended environmental conservation models, it is heavily influenced by western scientific discourses whose perspectives are far removed from the existential realities of local populations. in our observations, africans were and still conscious of the devastating consequences of the unsustainable utilisation of natural resources, which the shona people call, zvisikwa. this concept of zvisikwa is constitutive of a deep-seated symbolism whose interpretations and meanings are rooted in the religio-cultural milieu of the locals. specifically, this study is carried out among the ndau, a shona linguistic group in south-eastern zimbabwe. the traditional utilisation of natural resources is systematic and rational as people acknowledge the ability of land to continue to regenerate itself. it is this perceived paradigm of indigenous knowledge systems that the study embraces as it guarantees the continuity and harmony of the socio-cultural networks that ensure the survival of rural societies. key words: traditional religion, natural resources, indigenous knowledge systems, utilisation and environment. introduction the subject of the interrelatedness between traditional religion and ecology or environment continues to grow in contemporary african scholarship. this study is part of the surging debate concerning the link between traditional religion and natural resources. the article discusses the critical issues on the symbolism and utilisation of natural resources among the shona people, with special reference to the ndau linguistic group in south-eastern zimbabwe. the justification for choosing this distinctive linguistic group is that there are very few ethnographical studies that were carried out among these people as compared with the rest of the shona peoples (karanga, zezuru and korekore).the ndau share a common *corresponding author. e-mail: moven.mozenda@gmail.com heritage which tries to explore the vitality of indigenous knowledge systems in ecological management, yet they have been neglected. the focus is on exploring the significance of the indigenous knowledge systems concerning the utility of natural resources. dorahoppers (2001) as cited in maila and loubser (2003) defines indigenous knowledge systems as ‘knowledge that is characterised by its embeddedness in the cultural web and history of a people including their civilisation and which forms the backbone of the social, economic, scientific and technological identity of such people.’ in a traditional african context, according to sibanda (1997; 2000) natural resource use, management and conservation are products of people’s spirituality, culture, practices, taboo systems and knowledge accumulated over centuries. the major contention of this study is that the shona people, as represented by the south-eastern ndau linguistic group, moven et al. 349 view themselves as symbiotically related to the physical environment since nature is intimately and ultimately correlated to the spiritual world. this spiritual world manifests itself in the landscape through phenomena such as rocks, caves, pools, trees and animals, especially lions and eagles (fontein, 2006). in most african societies, as ranger (1999) has observed, nature and culture carry a symbiotic relationship with traditional religion. in concrete terms, it is this traditional religion that forms the core of a particularistic culture of local people in their situatedness. thus, the utilisation of natural resources is more than satisfying the immediate needs; but also a part of the conservation and celebration of human life (sibanda, 1997; 2000). it must be pointed out that the indigenous people utilise natural resources in quite systematic ways and with deep observance of a ‘rich tradition’ of norms, taboo systems and assorted practices that are grounded in the religio-cultural milieu. this body of belief system shapes local people’s interpretation of their perception of the accessibility and utility of the available natural resources. on the onset, it must be pointed out that the colonial assumptions that prejudiced the shona people as reckless and irresponsible with regard to the use and conservation of natural resources were very superficial. in our analysis, the colonial assumption was unfortunate because it merely expressed an egoistic conviction of the settler administration. moreover, the ontological perspective grounded in the western discourse places the african humanity in some sort of philosophically informed symbiotic context (light, 1997). it therefore suffices to assert that the colonial assumptions, as highlighted below, were just a way of alienating africans from their land than an attempt to offer alternative but more viable environmental management strategies. such adherence to western perceptions is seen in how the significance of indigenous knowledge systems has long been, until recently, virtually ignored and maligned by the government and international organisations (warren 1992; www.ciesin.org/docs/004-173.html). the post colonial government in zimbabwe adopted and extended the colonial pieces of legislation which were resented by the local communities as destructive to their livelihoods. wolmer (2007) asserts that the danger is that these initiatives will deepen antagonism over land and lead to further coercive regulations on natural resource use to be at odds with people’s livelihood strategies. the perception of scarcity of natural resources is virtually distorted as local people view themselves as invisible on the landscape they have lived in and identified themselves with over centuries. in a related study done around nyanga district, in the eastern highlands of zimbabwe, moore (2005) showed that the local women at kaerezi area complained and expressed scarcity of one natural resource, huni (firewood). the scarcity of huni was perceived to be as a result of mbawu (human greediness) that was impacted by the encroachment and extension of nyanga national park into the local people’s neighbourhoods. as such, the term and concept of zvisikwa (things created or rather, natural phenomena) occupies a central position in the interpretation of the symbols and utility of natural resource use and conservation among the ndau people. moore (2005) contends that zvisikwa are imbued with use-values and take on meaning through people’s daily livelihood struggles. there is a sense of collective responsibility on meaning that each and every member of the community is bound to ensure that he or she extracts resources from the physical environment without compromising the ability of present and future generations to meet their natural needs in a sustainable way. thus, zvisikwa does not posit an historical essence of natural resource use but it accommodates a range of cosmologies and religious idioms: a supreme being known as mwari, guardian spirits known as mhondoro and a plethora of wandering spirits known as mashavi. all these spiritual entities are perceived to hold responsibility in the process of creation. in light of the study findings, therefore, the old colonial hypothesis that africans are reckless and irresponsible in managing their ecology or environment is not justified anymore. rather, it must be asserted that the ndau people were and still conscious of the importance of conserving natural environment. this is how a paradox of conflicting realities about interpreting the environmental crisis comes to the forefront. the adoption by africans of such strategies such as poaching, deliberate burning of forests or woodlands and wanton killing of straying animals for meat must be understood in a wider context. this context ultimately points to an expression of resentment on part of the local people. in addition, as mcgregor (1991) (cited in alexander, 2006) has claimed, resistance is not so much of ‘misunderstanding’ the science of technical development but of seeing it as ‘irrationality involved in ruling africans and robbing them of resources.’ methodology and study delineation two interlinked methods, the phenomenological and participantobservation approaches were used in this study. both paradigms are relevant for field research. the phenomenological method was very handy because it is concerned with seeing a phenomenon or behaviour or religion as the adherents see them, rather that imposing any sort of external value judgement. in fact, the phenomeno-logical approach provided a means for investigating the way people come to know reality (cox, 1992). through the principle and process of epoche, that is, we were able to gather data after ‘bracketing’ any of the value judgements that outsiders can hold. accordingly, the ndau cultural beliefs and practices on the utilisation and management of natural resources were studied as pure categories, sui generis. the strength in the application of the phenomenological approach was the ability to differentiate between noumena (things as they are) from phenomena (things as we perceive them). by doing so, the first hand information was generated from the local people particularly when juxtaposed with the participant observation method. this methodological paradigm is located in ethnography as it grapples with the people’s belief systems, customs, taboos, fears, interests and cultural practices. 350 afr. j. envir. econ. manage. other districts of manicaland province study districts where the ndau are located figure 1. map showing the location of ndau people in chimanimani and chipinge districts of southeastern zimbabwe and an insert of southern africa region. source: adapted from alois mandondo (1997), institute of environmental studies, university of zimbabwe. in the application of the participant observation approach, we undertook a face-to-face interaction with the local people in their natural existential settings. we also undertook intensive interviewing and critical observation to what the people did when expressing their culture and religion vis -à-vis natural resource utility and conservation strategies. through the participant observation technique, the research was positively shaped in three ways, which are: 1. field investigation was done in situ, that is, in local people’s situatedness and culturedness. 2. our interaction with the people was direct and this yielded first hand data. 3. we gained understanding of the socio-cultural milieu that helped us to draw findings about their perspectives on natural resource use and ecological management. in light of these two methods, we were able to get deep into the ‘insider’s point of view’ and decode meaning of cultural beliefs, customs, taboos and traditions which govern the way locals use and conserve natural resources within their environment. these methods were very fruitful when corroborated by integral interviewing. literally, we got ‘our hands dirty’ during the six weeks, inbetween march and april 2010, when we conducted fieldwork among the ndau people in south-eastern zimbabwe. this south eastern geographical belt shares a ‘hard international border’ with mozambique in the east (figure 1). it is a hard border because the ndau people are found on either side of it, on account of colonial imposition despite their cultural homogeneity. the ndau people have lived in this area at least since the 15 th century and thus have a long-standing relationship with the land and its resources (anstey and de sousa, 2001). nevertheless, the study focussed on those local peoples found on the zimbabwean side only. two districts were chosen to carry out the study; these are chipinge and chimanimani districts. besides participant obser-vation, information was also collected through semi-structured interviews in chindau dialect. in chimanimani, interviews were conducted in a number of selected villages in muusha, chikukwa, mutambara and ngorima chieftaincies. in chipinge district interviews were also carried out in some selected villages in musikavanhu, mutema, mapungwana and garahwa chieftaincies. those interviews were targeted at the elderly people whom we consider are the credible custodians of ndau history, culture and traditions. result the paradox of competing perceptions different cultures hold divergent worldviews about the place of humanity within the universe. the major contention moven et al. 351 is on the place of humanity in the context of their environment. this raises questions about how humans may interact with nature especially vis-à-vis the utilisation of natural resources. two competing notions can be identified. on one hand, there is the dominance of the western worldview about natural resource conservation generated debate because of its failure to address environmental concerns and dilemmas especially in african communities. the shortcomings, according to schoffeleers (1978), rest on its failure to distinguish what is being said and the way it is being said by the africans themselves. on the other hand, there is an african perspective and does a call for a radical departure from the current understand. this latter perspective gives indigenous knowledge systems the importance they deserve with regard to natural resources utilisation and conservation. but, in as much as we have observed, both notions are conscious about the conservation of natural environment, the divergence is much on the extent humans dominates nature. both notions somehow converge at the anthropocentric idea that humans have the right to exploit natural resources, zvisikwa, as this is the order of nature that life forms depend on each other for survival. let us start by highlighting the western perspectives. some western notions the western notions about the relationship between people and environment construct humans as fundamentally isolated from the rest of nature. it perceives humanity as quite superior and in charge of the rest of creation (devall and sessions, 2000). as stated by wolmer (2007), the technocratic-industrial worldview constructs a wilderness image in which nature is seen as a potentially productive landscape or must be preserved in its pristine state. the wilderness is seen as a refuge or sanctuary in which those in need of consolation can find respite from the pressures of civilisation and modernity. to legitimise this kind of thinking, the colonial settlers introduced alien territorial paradigms such as private ownership and physical boundaries that subsequently resulted in land enclosures by way of fencing. as shall be highlighted later, this is in sharp contrast with the african worldview because this wilderness is also a place of human habitation since there were no discrete boundaries between people’s communities and natural environment. some african notions in describing african perspective, croll and parkin (1992) (wolmer, 2007) have stated that ‘humans and their changing environments are reciprocally inscribed in cosmological ideas and cultural understanding, they are part of each other: the forest is the people, in thesame way that ancestors can be, in a sense, extensions of the living’. like the rest of shona linguistic speakers, the ndau people regard nature and society as inseparable. the ndau have a spiritual veneration of the natural landscape as it has a symbol of ancestral (vadzimu) and other guardian spirits (mhondoro). they not only live on land but also off land since this land is symbolically viewed as serving social, economic, religious and ecological roles. in other words, the success in managing nature is inextricably linked to proper management and control of society. information gathered from fieldwork in chipinge and chimanimani districts does confirm that the ndau people were sent by their chiefs to perform rituals whilst nude, spirit-possessed and where they sat down became the boundary of the village. as such, this space is a socially and religiously constructed landscape that does not need ‘hard-hedged’ boundaries to separate humans from nature. symbolism and utility of natural resources the ndau people have a holistic understanding of nature that manifests itself in the symbolism and the way they utilise natural resources. like other shona groups, the ndau people take into account the interests of not only sentiment beings but the whole of nature in general (masaka, 2009). the preference of species not only depends on the utility of species but also on the symbolic meanings and interpretations that are rooted in their cosmic vision. as anstey and de sousa (2001) have claimed, the rules and regulations relating to the use of natural resources and the allocation of land are mediated through a combination of spiritual considerations and the unwritten customary law. as a number of our informants for the study have affirmed, the ndau strongly believe that continuity of social, religious and economic aspects of life can be sustained by living in harmony with the environment itself. therefore, the ndau show their gesture of veneration by making some forests, animals and other parts of the natural landscape sacred. the value the ndau place on the regeneration of the environment is inextricably linked to the centrality of descendants in their tradition. in other words, the continuity of the society rests on the concept of descendants and regeneration of the environment. the complexity of this relationship always makes the ndau to jealously restrict access to resources by lineage and kinship ties in order to regulate competition from foreigners. competition is interpreted as a source of mbawu (human greediness). as much as we have found out, mbawu is always perceived by the ndau people as very inimical to sustainable utilisation of natural resources in their environment. accordingly, mbawu has no place in the proper utilisation of natural resources among the traditional ndau people. the guiding principle is that present generations are customarily obliged to even reserve some land resources for future generations. the ndau have a positive attitude towards non-human animals. their dislike of cruelty to non-humans, animals and the environment itself is reflected through taboos (masaka, 2009). taboos are designed to enforce positive societal attitudes towards the environment (duri and mapara, 2007) . the ndau, through the observance of taboos, were and still are able to control the indiscriminate harvesting of forest products, protect water sources and species of spiritual, nutritional and medicinal value and even rare species. for instance, ordinary people do not kill an animal called haka, a pangolin that carries special status in shona communities. its shells are used by n’angas, that is, traditional diviners when engaged in divination to get spiritual knowledge on behalf of their consultants. due to its special status, therefore, the pangolin is only reserved for chiefs to be eaten on special ritual occasions (anstey and de sousa, 2001). what must be emphasised is that most of the taboos were designed in a way that people fear even to make negative comments or ridicule anything they see in the forests or mountains. such a view symbolically means that the ndau possess a critical concern for conservation of natural resources. this critical concern is part and parcel of a venerable attitude that is more or less sacral in nature. as we have seen, some animals are given honorific titles that are similar to those given to respect the elderly members of the society. for instance, baboons are given honorific titles such as ‘sekuru’ (grandfather) (pfukwa, 2001) meaning wisdom. elders are viewed as sources of wisdom among shona groups. for a traveller, an early morning bark of baboon was taken as a sign that all was well (pfukwa, 2001). in addition, when one came across a troop of baboons whilst on a journey, the ndau people interpreted it as a good omen. like the rest of the other shona groups, the ndau people have a culture of giving themselves mitupo, that is, totems. these totems are usually derived from the names of animals or from natural phenomenon such as a landscape or a pool. from the sociological perspective, the system of totemism is functional. firstly, it helps to protect the environment as well as controlling personal behaviour and social arrangements. secondly, totemism fosters the concept of ‘unhuism’. this concept of ‘unhuism’ is anchored around human notions of virtue. in light of our findings, unhuism occupies a central place in influencing how people behave and interact with nature since the members of the society are socialised to act in moderation in all aspects of life. for instance, the use of totems helps to control the problem of incest since such deviant behaviour is believed to have some linkages with incidences of catastrophic events such as drought. thirdly, totemism helps to maintain a sense of identity, that is, a feeling of belongingness and which is linked to a conviction of collective responsibility in society. it therefore symbolically means that the utilisation of natural resources is not only a matter of technology but also of 353 afr. j. envir. econ. manage. an ordered social life (schoffeleers, 1978) . it must also be mentioned that natural resources have both tangible and intangible utilities that range from serving the physical needs to their significance in the religious lives of the people. as nhira et al. (1998) have observed, trees and forests play key roles in household production in the rural communities of zimbabwe. of particular note is the fact that natural environment provides timber and nontimber forest products, wildlife and water resources, among others. the non-timber forest products include grazing and browsing, traditional medicines, wild fruits, fuel wood, litter leaf, craft materials and construction materials. of great note is the fact that the pattern of natural resource utility among the ndau is centred around the emphasis they place on the multipurpose of species and the sacredness of selected species. in other words, this pattern is a by-product of the veneration of socially selected sacred species and places as well as the role of species to human health as sources of food and medicines and their importance in household production and reproduction. for instance, as our informant has claimed, mutarara (gardenia globiflora) tree is not used for construction purposes because it is placed on top of graves protect the corpses of the dead people against witches’. such selective use of species is deeply rooted in the religious worldview of the ndau people and posits an intimate relationship between the social life and environmental management. it must be highlighted that much of the south-eastern region where the ndau people are located, is dotted with several sacred places and whereto ancestors are regarded with high esteem in the causal life of the people. people are ‘educated’ from cradle to death not to cut trees or do any activity that is destructive to the natural landscape. however, people are allowed to gather fruits and dead wood. suffice to state that the ndau people through religious prescriptions and prohi-bitions are able to regulate patterns of forest products utilization. from our observation, such areas are still endowed with forests and are abundant with diversity in tree species including the common miombo woodland species such as mnondo (julbernadia globifora), musasa (brachystegia spiciformis) and mupfuti (brachystegia boehmii). as in many parts of zimbabwe, the ndau people have a complex system that fuses environmental manage-ment into social life. there are traditional arrangements that promote sustainable utilization of natural resources. one informant summarized that the community ensures that everyone has a place to stay and farm. even when people go hunting they share the parts of the killed animal regardless of how small it is and how many hunters there are. social life emphasizes collective responsibility that is extended to environmental conservation. people have a selfless conviction to conserve and safeguard the environment because they acknowledge moven et al. 354 that the community is the custodian of natural resources while the individual belongs to the community. newcomers, for instance, do not apportion themselves land but have to consult the ‘indigenous’ people in the locality. as one informant said, ‘a person cannot just come and peg where to stay because he has to respect zvibarirwe zvemwo (those born in the area)’. such a gesture constitutes two implications that are relevant for the study. firstly, it is a gesture of immeasurable respect to zvibarirwe zvemwo. secondly, it regulates and stifles the practice of mbawu (human greediness). in ndau cosmic vision, vadzimu, the ancestral spirits, are viewed as having a more or less equal role as the living with regard to both the utilization of natural resources and their conservation. these ancestors are many times consulted by people to give advice and guidelines on how to share and distribute zvisikwa in ways that reflect human values of equity, fairness and justice. when there is a lack or an infringement of these values ancestors can cause mishaps to befall the malcontents. several mysterious incidents encountered by people who break ancestral rules and regulations are awash in ndau society and traditions. our informant narrated a tradition in which a calamity occurred to a wayward person. the tradition says that a man bathed in a sacred pool in matsika river with a bar of soap but all his belongings mysteriously disappeared, and he shamelessly went home in the nude. in evaluating this tradition, among others, we see that it acts as a deterrent to other would-be ‘lawbreakers’ so that no one would never ever attempt to bath in the same sacred pool. in functional terms the tradition discourages wayward people not to pollute or destroy the environment. this is one practical way the ndau come to conserve their environment each time every person is conscious to respect the traditions of the people as a collective group and as a cultural unit. in our analysis, this is how traditions of a people in any cultural milieu are part of a rich indigenous knowledge system and when linked to natural resources conservation, become an effective strategy. conclusion the significance of indigenous knowledge systems in environmental management programmes is neglected yet it is vital if local communities have to fully participate in environmental conservation. as the study has indicated, the neglect is not due to irrelevance of the indigenous knowledge system in environmental management but it is rather the failure to understand environmental concerns and dilemmas of the africans. it was noted that the ndau people have a rich tradition of norms and taboo systems that are grounded in the religio-cultural milieu. their relevance and vibrancy in the utilization and conservation of natural resources, zvisikwa, should not be underestimated. the indigenous knowledge systems should be an integral part of local community participation in environmental management strategies from the foundation of the formulation phase to implementation. references alexander j (2006). the unsettled land: state making & the politics of land in zimbabwe 1893 – 2003, harare: weaver press. anstey s, de-sousa c (2001). 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1 (5), pp. 126-143, december, 2013. available online at www.internationalscholarsjournals.org © international scholars journals review economics and environmental impact of bioethanol production technologies: an appraisal anuj kumar chandel 1,2 , chan es 3 , ravinder rudravaram 1 , m. lakshmi narasu 2 , l. venkateswar rao 1 and pogaku ravindra 3 * 1 department of microbiology, osmania university, hyderabad-500 007, india. 2 department of biotechnology, jawaharlal nehru technological university, hyderabad-500 007, india. 3 school of engineering and information technology, universiti malaysia sabah,kotakinabalu, 88999, malaysia. accepted 25 may, 2013 contemporary industrial developments and rapid pace of urbanization have called for an environmentally sustainable energy sources. ethanol made from biomass provides unique environmental, economic strategic benefits and can be considered as a safe and cleanest liquid fuel alternative to fossil fuels. there is a copious amount of lignocellulosic biomass worldwide that can be exploited for fuel ethanol production. significant advances have been made at bench scale towards the fuel ethanol generation from lignocellulosics. however there are still technical and economical hurdles, which make the bioethanol program unsuccessful at commercial scale. this review provides a broad overview on current status of bioethanol production technologies in terms of their economic and environmental viability. these technologies include pretreatment of biomass, the use of cellulolytic enzymes for depolymerisation of carbohydrate polymers into fermentable constituents and the use of robust fermentative microorganisms for ethanol production. among all the available technologies, dilute acid hydrolysis followed by enzymatic hydrolysis by less expensive and more efficient cellulases has been found more promising towards the potential economics and environmental impact. key words: bioethanol, lignocellulosic feedstock, ethanol fermentation, economics, environmental impact. table of contents 1. introduction 2. lignocellulosic biomass 2.1. composition 3. ethanol production technologies 3.1. pretreatment 3.1.1. hydrolysis 3.2.1. acid hydrolysis 3.2.1.1 dilute acid hydrolysis 3.2.1.1.1 first-stage dilute acid hydrolysis 3.2.1.1.2 two-stage dilute acid hydrolysis 3.2.1.2. concentrated acid hydrolysis 3.2.2 enzymatic hydrolysis 3.2.2.1 separate hydrolysis and fermentation (shf) 3.2.2.2 simultaneous saccharification and fermentation (ssf) 3.3. direct microbial conversion (dmc) 3.4 fermentation 3.4.1. batch fermentation 3.4.2 fed batch fermentation 3.4.3. continuous fermentation 3.4.3.1. immobilized cells 3.4.3.2 recycling of process stream 4. economics of ethanol production technologies 5.1. ethanol and environment 5.2. environmental impact of bioethanol production technologies and their life-cycle assessment (lca) chandel et al. 126 6. conclusion 7. references introduction in 1925, henry ford had quoted ethyl alcohol, ethanol, as "the fuel of the future.” he furthermore stated, "the fuel of the future is going to come from apples, weeds, sawdust – almost anything. there is fuel in every bit of vegetable matter that can be fermented." today henry ford’s futuristic vision significance can be easily understood. in the current time, the importance of alternative energy source has become even more necessary not only due to the continuous depletion of limited fossil fuel stock but also for the safe and better environment, with an inevitable depletion of the world’s energy supply, there has been an increasing worldwide interest in alternative sources of energy (wyman, 1999; lynd, 2004; herrera, 2004; herrera, 2006; lin and tanaka, 2006, schubert, 2006; chandel et al., 2006a; vertes et al., 2006, dien et al., 2006). keeping in view all the above said advantages, biomass based fuel development technologies should rapidly gain momentum and the barriers imposed earlier should be removed for successfully attempting the production of bioethanol at the commercial level. it is welcome to understand that the use of bioethanol as a source of energy would be more than just complementting for solar, wind and other intermittent renewable energy sources in the long run (lin and tanaka, 2006). during the last two decades, advances in technology for ethanol production from biomass have been developed to the point that large-scale production will be a reality in next few years (yu and zhang, 2004; moiser et al., 2006). ethanol production from biomass can be summarized briefly into following steps: depolymerization of holocellulose polymer into monomeric fermentable substrate, fermentation of depolymerized substrates, and the distillation of the fermentation broth to obtain dehydrated ethanol. the ethanol yields and processes economics along with the technical maturity and environmental benefits of using ethanol blend fuel are the key parameters that determine the feasibility of bioethanol production (nguyen and saddler, 1991). the burning fossil fuel at the current rate is likely to create an environmental crisis globally. use of fossil fuel generates carbon dioxide, methane and a significant quantity of nitrous oxide. most of these harmful gases are formed due to incomplete combustion of fossil fuel; since ethanol contains 35% oxygen that may result in a more complete combustion of fuel and thus reduces tailpipe emissions. *corresponding author. e-mail: dr_ravindra@hotmail.com. phone: 006 088 320000 ext 3048. mobile: 006 013 87666634. fax: 006 088 320348. moreover, biomass energy can play an important role in reducing green house gas emissions. ethanol production process only uses energy from renewable energy sources. hence no net carbon dioxide is added to the atmosphere, making ethanol an environmentally beneficial energy source (bull et al., 1992; kheshgi et al., 2000). furthermore, fuel ethanol from lignocelluloses may also open new employment opportunities in rural areas, and thus make a positive socio-economic impact (wyman, 2003; bevan and franssen, 2006). developing ethanol as fuel, beyond its current role as fuel oxygenates will require developing lignocellulosic biomass as a feedstock because of its abundantly available and low cost. the world ethanol production in 2004 was estimated to be 40 giga litres (gl) (berg, 2004; kim and dale, 2004). brazil and the us are the world leaders, which together accounted for about 60% of the world ethanol production exploiting sugarcane and corn respectively. in india, lignocellulosic biomass (crop residues, forestry and fruit and vegetable waste and weeds) is available in plenty. renewable fuels particularly ethanol should get more and more attention all over the world. the important issue that we wish to address affirmatively here is that the bioethanol production, without doubt, needs an economical approach to address the global fuel needs. research efforts are needed to design and improve the process, which would produce sustainable and economically feasible transportation fuel. improvement in process economics using new designed cellulases enzyme cocktail are important factors in establishing a cost effective technology, besides the low cost of feedstock (mojovic et al., 2006; gray et al., 2006). for the long haul, it is very important to understand bioethanol production technologies in terms of their economic viability, environmental feasibility and empowering employment opportunities before implementing a fuel ethanol policy. the choice of the best technology for lignocellulose to bioethanol conversion should be decided on the basis of overall economics (lowest cost), environmental (lowest pollutants) and energy (higher efficiencies)that is, comprehensive process development and optimization are still required to make the process economically viable. in reality, environmental considerations, energy and tax policies will determine the extent of fuel ethanol utilization in the future (keim and venkatasubramanian, 1989) and therefore the role of one and all is very crucial to identify the gravity of the situation associated with bioethanol production and use of it as an alternative fuel. the focus of this review is on the current status of available ethanol production technologies in terms of their 127 afr. j. environ. econ. manage. practical cost economics and the desirable environmental impact they have for a whole generation of commuters across the globe. lignocellulosic biomass composition basically, the lignocellulosic biomass comprises of cellulose, hemicellulose and lignin (hayn et al., 1993). cellulose is a linear, crystalline homopolymer with a repeating unit of glucose strung together beta-glucosidic linkages. the structure is rigid and harsh treatment is required to break it down (gray et al., 2006). hemi-cellulose consists of short, linear and highly branched chains of sugars. in contrast to cellulose, which is a polymer of only glucose, a hemicellulose is a hetero-polymer of d-xylose, dglucose, d-galactose, d-man-nose and l-arabinose (saha et al., 2003). the composi-tion of holocellulose (cellulose + hemicellulose) varies with the origin of the lignocellulosic material. table 1 shows the composition of the selected crop residues, woody materials, vegetable and fruit waste and municipal solid waste and their simulated ethanol production. ethanol production has been taken into estimation depending upon the ratio of hexosans (glucan, galactan and mannan) and pentosans (xylan, arabinan) in each biomass source. the ethanol production from each bio-mass sources was calculated / ascertained from us department of energy website, which provide “theoretical ethanol yield calculator” at http://www.eere.ene-rgy.gov/biomass/ethanol_yield_calculator.html. ethanol production technologies bioconversion of lignocellulosics to ethanol consists of four major unit operations: pretreatment, hydrolysis, fermentation and product separation/ distillation. pretreatment pretreatment is required to alter the biomass macroscopic and microscopic size and structure as well as its submicroscopic chemical composition and structure so that hydrolysis of carbohydrate fraction to monomeric sugars can be achieved more rapidly and with greater yields (sun and cheng, 2002; moiser et al., 2005). pretreatment affects the structure of biomass by solubilizing hemicellulose, reducing crystallinity and increase the available surface area and pore volume of the substrate. pretreatment has been considered as one of the most expensive processing step in biomass to fermentable sugar conversion with cost as high as 30 cents/gallon ethanol produced (moiser et al., 2005). to asses the cost and performance of pretreatment methods, technoeconomic analysis have been made recently (eggerman and elander, 2005). there is huge scope in lowering the cost of pretreatment process through extensive r&d approaches. pretreatment of cellulosic biomass in cost effective manner is a major challenge of cellulose to ethanol technology research and development. native lignocellulosic biomass is extremely recalcitrant to enzymatic digestion. therefore, a number of thermochemical pretreatment methods have been developed to improve digestibility (wyman et al., 2005). recent studies have clearly proved that there is a direct correlation between the removal of lignin and hemi-cellulose on cellulose digestibility (kim and holtzapple, 2006). thermochemical processing options appear more promising than biological options for the conversion of lignin fraction of cellulosic biomass, which can have a detrimental effect on enzyme hydrolysis. it can also serve as a source of process energy and potential co-products that have important benefits in a life cycle context (sheehan et al., 2003). pretreatment can be carried out in different ways such as mechanical combination (cadoche and lopez, 1989), steam explosion (gregg and saddler, 1996), ammonia fiber explosion (kim et al., 2003), acid or alkaline pretreatment (damaso et al., 2004; kuhad et al., 1997) and biological treatment (keller, et al., 2003). hydrolysis after pretreatment there are two types of processes to hydrolyze the feed stocks into monomeric sugar constituents required for fermentation into ethanol. the hydrolysis methods most commonly used are acid (dilute and concentrated) and enzymatic. to improve the enzymatic hydrolytic efficiency, the ligninhemicellulose net work has to be loosened for the better amenability of cellulases to residual carbohydrate fraction for sugar recovery. dilute acid treatment is employed for the degradation of hemicellulose leaving lignin and cellulose network in the substrate. other treatments are alkaline hydrolysis or microbial pretreatment with white-rot fungi (phaenerochate chrysosporium, cyathus stercoreus, cythus bulleri and pycnoporous cinnabarinus etc.) preferably act upon lignin leaving cellulose and hemicellulose network in the residual portion. however during both treatment processes, a considerable amount of carbohydrates are also degraded, hence the carbohydrate recovery is not satisfactory for ethanol production. acid hydrolysis there are two types of acid hydrolysis process commonly used dilute and concentrated acid hydrolysis. the dilute acid process is conducted under high temperature and pressure and has reaction time in the range of seconds or minutes. the concentrated acid process uses relatively mild temperatures, but at high concentration of sulfuric acid and a minimum pressure involved, which only creates by pumping the materials from vessel to vessel. reaction times are typically much longer than for dilute acid table 1. chemical composition of raw materials and simulated ethanol production raw material cellulose/ hemicellulose / lignin ethanol yield reference hexosans (h) pentosans (p) /kg dry mass sugarcane baggase 33 (h) 30 (p) 29 0.279 kuhad and singh, 1993 wheat straw 30 (h) 24 (p) 18 0.239 kuhad and singh, 1993 sorghum straw 33 (h) 18 (p) 15 0.240 kuhad and singh, 1993 rice straw 32 (h) 24 (p) 13 0.248 kuhad and singh, 1993 oat straw 41 (h) 16 (p) 11 0.252 kuhad and singh, 1993 corn cob 42 (h) 39 (p) 14 0.358 kuhad and singh, 1993 corn stalks 35 (h) 15 (p) 19 0.221 kuhad and singh, 1993 barley straw 40 (h) 20 (p) 15 0.265 kuhad and singh, 1993 ground nut shell 38 (h) 36 (p) 16 0.327 kuhad and singh, 1993 alfalfa stalks 48.5 6.5 16.6 0.209 shleser, 1994 rice hulls 36 (h) 15 (p) 19 0.265 kuhad and singh, 1993 eucalyptus grandis 38 13 37 0.225 shleser, 1994 eucalyptus saligna 45 12.0 25.0 0.252 shleser, 1994 pine 44.0 26.0 29.0 0.310 olsson and hagerdal, 1996 poplar 47.6 27.4 19.2 0.332 olsson and hagerdal, 1996 saw dust 55.0 14.0 21.0 0.305 olsson and hagerdal, 1996 willow 37.0 23.0 21.0 0.265 olsson and hagerdal, 1996 aspen 51 29.0 16.0 0.354 olsson and hagerdal, 1996 spruce 43.0 26.0 29.0 olsson and hagerdal, 1996 birch 40.0 23.0 21.0 0.305 olsson and hagerdal, 1996 lantana camara 42.50 22.70 22.88 0.288 chandel (unpublished work) prosopis juliflora 45.5 20.38 24.65 0.291 chandel (unpublished work) saccharum spontaneum 45.10 22.70 24.56 0.300 gupta, 2006 eicchornia crassipis 18.2 48.7 3.50 0.296 nigam, 2002 paja brava 32.2 28.1 24.0 0.267 sanchez et al., 2004 news paper 61 16 21 0.341 olsson and hagerdal, 1996 processed paper 47 25 12 0.318 olsson and hagerdal, 1996 paper-based municipal 43 13 6 0.248 olsson and hagerdal, 1996 solid waste process dilute acid hydrolysis in dilute acid hydrolysis, the hemicellulose fraction is depolymerized at lower temperature than the cellulosic fraction. dilute sulfuric acid is mixed with biomass to hydrolyse hemicellulose to xylose and other sugars. dilute acid is interacted with the biomass and the slurry is held at temperature ranging from120 220°c for a short period of time. thus hemicellulosic fraction of plant cell wall is depolymerised and will lead to the enhancement of cellulose digestibility in the residual solids (nigam, 2002; sun and cheng, 2002; dien et al., 2006; saha et al., 2005). dilute acid hydrolysis has some limitations. if higher temperatures (or longer residence time) are applied, the hemicelluosic derived monosaccharides will degrade and give rise to fermentation inhibitors like furan compounds, weak carboxylic acids and phenolic compounds (olsson and hahnhagerdal, 1996; klinke et al., 2004; larsson et al., 1999). these fermentation inhibitors are known to affect the ethanol production performance of fermenting microorganisms (chandel et al., 2006b). in order to remove the inhibitors and increase the hydrolysate fermentability, several chemicals and biological methods have been used. these methods include overliming (martinez et al., 2000), charcoal adsorption (chandel et al., 2006b), ion exchange (nilvebrant, 2001), detoxification with laccase (martin et al., 2002; chandel et al., 2006b), and biological detoxification (lopez et al., 2004). the detoxification of acid hydrolysates has been shown to improve their fermentability; however, the cost is often higher than the benefits achieved (palmqvist and hahnhagerdal, 2000; von sivers and zacchi, 1996). dilute acid hydrolysis is carried out in two stagesfirst-stage and two-stage. first-stage dilute acid hydrolysis the lignocellulosic material is first contacted with dilute chandel et al. 128 129 afr. j. environ. econ. manage. sulfuric acid (0.75%) and heated to approximately 50°c followed by transferring to the first stage acid impregnator where the temperature is raised to 190°c. approximately, 80% of the hemicellulose and 29% of cellulose are hydrolyzed in the first reactor. the hydrolysate is further incubated at a lower temperature for a residence time of 2 h to hydrolyse most of the oligosaccharides into monosaccharides followed by the separation of solid and liquid fractions. the solid material again washed with plentiful of water to maximize sugar recovery. the separated solid material is sent to second stage acid hydrolysis reactor (figure 1). two-stage dilute acid hydrolysis in two-stage dilute acid hydrolysis process, first, biomass is treated with dilute acid at relatively mild conditions during which the hemicelluose fraction is hydrolyzed and the second stage is normally carried out at higher temperature for depolymerisation of cellulose into glucose. the liquid phase, containing the monomeric sugars is removed between the treatments, thereby avoiding degradation of monosaccharides formed (figure 1). it is very important to avoid monosaccharide degradation products for improving the ethanol yield. sanchez et al. (2004) carried out the two-stage dilute acid hydrolysis using bolivian straw material, paja brava. in first stage, p. brava material was pretreated with steam followed by dilute sulfuric acid (0.5 or 1.0% by wt) hydrolysis at temperatures between 170 and 230°c for a residence time between 3 and 10 min. the highest yield of hemicellulose derived sugars were found at a temperature of 190°c, and a reaction time of 5 – 10 min, whereas in second stage hydrolysis considerably higher temperature (230 °c) was found for hydrolysis of remaining fraction of cellulose. concentrated acid hydrolysis this method uses concentrated sulfuric acid followed by a dilution with water to dissolve and hydrolyse the substrate into sugar constituents. this process provides complete and rapid conversion of celluose to glucose and hemicellulose to xylose with a little degradation. the concentrated acid process uses 70% sulfuric acid at 40 50°c for 2 to 4 h in a reactor. the low temperatures and pressure will lead to minimize the sugar degradation. the hydrolyzed material is then washed to recover the sugars. in the next step, the cellulosic fraction has to be deploymerized. the solid residue from first stage is de-watered and soaked in 30 40% sulfuric acid for 50 min. at 100°c for further cellulose hydrolysis. the resulting slurry mixture is pressed to obtain second acid–sugar stream (approximately 18% sugar and 30% acid). both the sugar steams from two hydrolysis steps are combined and may be used for subsequent ethanol production. iranmahboob et al. (2002) performed the concentrated acid hydrolysis of mixed wood chips and found that maximum sugar recovery (78 82% of theoretical yields) was achieved at sulfuric acid concentration (26%) for 2 h of residence time. the primary advantage of the concentrated acid process is the potential for high sugar recovery efficiency, about 90% of both hemicellulose and cellulose fraction gets depolymerized into their monomeric fractions. the acid and sugar syrup are separated via ion exchange and then acid is reconcentrated through multiple effect evaporators. the remaining lignin rich solids are collected and optionally palletized for fuel generation (figure 2). enzymatic hydrolysis the acid, alkaline or fungal pretreated lignocellulosics can be saccharified enzymatically to get fermentable sugars (ghose and bisaria, 1979; kuhad et al., 1997; itoh et al., 2003; tucker et al., 2003). bacteria and fungi are the good sources of cellulases, hemicellulases that could be used for the hydrolysis of pretreated lignocellulosics. the enzymatic cocktails are usually mixtures of several hydrolytic enzymes comprising of cellulases, xylanases, hemicellulases and mannanases. in the last decade, new cellulases and hemicellulases from bacterial and fungal sources have continued been isolated and regular efforts have been made for the improved production of enzymetic titers (aro et al., 2005; foreman et al., 2003). however, the cellulases were produced at a concentration too low to be useful. there is a group of microorganisms (clostridium, cellulomonas, tricho-derma, penicillium, neurospora, fusarium, aspergillus etc.) showing a high cellulolytic and hemicellulolytic activity, which are also highly capable of fermenting monosaccharides. genetic engineering is used to produce super strains, which are capable of hydrolysing cellulose and xylan along with fermentation of glucose and xylose to ethanol (aristidou and penttila, 2000; lin and tanaka, 2006). the utilization of cellulose by microorganisms involves a substantial set of fundamental phenomena beyond those associated with enzymatic hydrolysis of cellulose (lynd et al., 2002). separate hydrolysis and fermentation (shf) enzymatic hydrolysis performed separately from fermentation step is known as separate hydrolysis and fermentation (shf) (sreenath et al., 2001; wingren et al., 2003). the separation of hydrolysis and fermentation offers various processing advantage and opportunities. it enables enzymes to operate at higher temperature for increased performance and fermentation organisms to operate at moderate temperatures, optimizing the utilization of sugars (figure 3). chandel et al. 130 figure 1. dilute acid hydrolysis (first-stage and two-stages) and separate fermentation of pentose and hexose sugars. simultaneous saccharification and fermentation (ssf) the most important process improvement made for the enzymatic hydrolysis of biomass is the introduction of simultaneous saccharification and fermentation (ssf), which has been improved to include the co-fermentation of multiple sugar substrates (figure 4) (sreenath et al., 2001; wingren et al., 2003). this approach combined the cellulase enzymes and fermenting microbes in one vessel. this enabled a one-step process of sugar production and fermentation into ethanol. simultaneous saccharification of both carbon polymer, cellulose to glucose; and hemicellulose to xylose and arabinose; and, fermentation will be carried out by recombinant yeast or the organism which has the ability to utilize both c5 and c6 sugars. according to alkasrawi et al. (2006) the mode of preparation of yeast must be carefully considered in ssf designing. a more robust strain will give substantial process advantages in terms of higher solid loading and possibility to recirculate the process stream, which results in increased energy demand and reduced fresh water utilization demand in process. adaptation of yeast to the inhibitors present in the medium is an important factor for consideration in the design of ssf process. more recently, kroumov et al. (2006) demonstrated an unstructured model of ssf of starch to ethanol by genetically modified strain saccharomyces cereviseae ypb-g, using two hierarchic levels of concept. in first concept, a mechanism of enzymatic hydrolysis of starch to glucose by combined action of two enzymes (alphaamylase and glucoamylase) secreted by recombinant yeast and the second concept was the enzymatic degradation of starch to glucose and simultaneous utilization of glucose to ethanol by microorganisms. ssf combines enzymatic hydrolysis with ethanol fermentation to keep the concentration of glucose low. the accumulation of ethanol in the fermenter does not inhibit cellulase action as much as high concentration of glucose; so, ssf is good strategy for increasing the overall rate of cellulose to ethanol conversion (lin and tanaka, 2006) . ssf gives higher ethanol yield while requiring lower amounts of enzyme because endproduct inhibition from cellobiose and glucose formed during enzymatic hydrolysis is relieved by the yeast fermentation (banat et al., 1998). however, it is not feasible for ssf to 131 afr. j. environ. econ. manage. figure 2. concentrated acid hydrolysis and separate pentose and hexose sugars fermentation. meet all the challenges at industrial level due to its low rate of cellulose hydrolysis and most microorganisms employed for ethanol fermentation can not utilize all sugars derived after hydrolysis. to overcome of this problem, the cellulolytic enzyme cocktail should be more stable in wide range of ph and temperature. also the fermenting microorganisms (yeasts or bacteria) should be able to ferment a wide range of c5 and c6 sugars. recently matthew et al. (2005) has found some promising ethanol producing bacteria viz. recombinant e. coli k011, klebsiella oxytoca, and zymomonas mobilis for industrial exploitation. ssf process has now improved after including the co-fermentation of multiple sugar subs trates present in the hydrolysate. this new variant of ssf is known as simultaneous saccharification and cofermentation (sscf) (wilke et al., 1976; patel et al., 2005; wyman et al., 2005). ssf and sscf are preferred over shf, since both operations can be performed in the same tank resulting in lower cost, higher ethanol yield and shorter processing time (wright et al., 1988). the most upgraded form of biomass to ethanol conversion is consolidated bioprocessing (cbp) featuring cellulose production, cellulose hydrolysis and fermentation in one step-is a highly integrated approach with outstanding potential (lynd et al., 2005). it has the potential to provide the lowest cost route for biological conversion of cellulo figure 3. shf with separate pentose and hexose sugars and combined sugar fermentation. figure 4. ssf with combined sugars (pentoses and hexoses) fermentation. chandel et al. 132 133 afr. j. environ. econ. manage. losic biomass to ethanol with high rate and desired yields. direct microbial conversion (dmc) dmc is a method of converting cellulosic biomass to ethanol in which both ethanol and all required enzymes are produced by a single microorganism. the potential advantage of dmc is that a dedicated process step for the production of cellulase enzyme is not necessary. cellulase enzyme production (or procurement) contributes significantly to the cost involved in enzymatic hydrolysis process. however, dmc is not considered the leading process alternative. this is because there is no robust organism available that can produce cellulases or other cell wall degrading enzymes in conjunction with ethanol with a high yield. singh and kumar (1991) found that several strains of fusarium oxysporum have the potential for converting not only d-xylose, but also cellulose to ethanol in a one-step process. distinguishing features of f. oxysporum for ethanol production in comparison to other organisms are identified. these include the advantage of in situ cellulase production and cellulose fermentation, pentose fermentation, and the tolerance of sugars and ethanol. the main disadvantage of f. oxysporum is its slow conversion rate of sugars to ethanol as compared to yeast. fermentation bioconversion of various biomass sources into ethanol by different microorganisms has been summarized in table 2. the sugar syrup obtained after cellulosic hydrolysis is used for ethanol fermentation. the ability to ferment pentoses along with hexoses is not widespread among microorganisms (toivolla et al., 1984), s. cereviseae is capable of converting only hexose sugars to ethanol. the most promising yeasts that have the ability to use both c5 and c6 sugars are pichia stipitis, candida shehatae and pachysolan tannophilus. however, ethanol production from sugars derived from starch and sucrose has been commercially dominated by the yeast s. cereviseae (lin and tanaka, 2006). thermotolerant yeast could be more suitable for ethanol production at industrial level. in high temperature process energy savings can be achieved through a reduction in cooling costs. considering this approach, sree et al. (1999) developed solid state fermentation system for ethanol production from sweet sorghum and potato employing a thermotolerant s. cereviseae strain (vs3). researches are now focusing on developing recombinant yeast, which can greatly improve the ethanol production yield by metabolizing all form of sugars, and reduce the cost of operation. in this contention the researchers have made efforts by following two approaches. the first approach has been to genetically modify the yeast and other natural ethanologens additional pentose metabolic pathways. the second approach is to improve ethanol yields by genetic engineering in microorganisms that have the ability to ferment both hexoses and pentoses (jeffries and jin, 2000; dien et al., 2003; katharia et al., 2006). jeffries and jin (2004) compiled the recent developments happened towards the genetic engineering of yeast metabolism and concluded that strain selection through mutagenesis, adaptive evolution using quantitative metabolism models may help to further improve their ethanol production rates with increased productivities. piskur et al., (2006) showed the recent developments in comparative genomics and bioinformatics to elucidate the high ethanol production mechanism from saccharomyces sp. though new technologies have greatly improved bioethanol production yet there are still a lot of problems that have to be solved. the major problems include maintaining a stable performance of genetically engineered yeast in commercial scale fermentation operation (ho et al., 1998, 1999), developing more efficient pre-treatment technologies for lignocellulosic biomass, and integrating optimal component into economic ethanol production system (dien et al., 2000). sridhar and co-workers (2002) made an effort to improve the thermo tolerance of yeast isolates by treating them with uv radiation. fermentation can be performed as a batch, fed batch or continuous process. the choice of most suitable process will depend upon the kinetic properties of microorganisms and type of lignocellulosic hydrolysate in addition to process economics aspects. batch fermentation traditionally, ethanol has been produced batch wise. at present, nearly, all of the fermentation ethanol industry uses the batch mode. in batch fermentation, the microorganism works in high substrate concentration initially and a high product concentration finally (olsson and hanhagerdal, 1996). the batch process is a multi-vessel process, allows flexible operation and easy control over the process. generally batch fermentation is characterized by low productivity with an intensive labour (shama, 1988). for batch fermentation, elaborate preparatory procedures are needed; and because of the discontinuous start up and shut down operations, high labour costs are incurred. this inherent disadvantage and the low productivity offered by the batch process have led many commercial operators to consider the other fermentation methods. fed batch fermentation in fed batch fermentation the microorganism works at low substrate concentration with an increasing ethanol concentration during the course of fermentation process. fed batch cultures often provide better yield and productivities than batch cultures for the production of microbial metabolites. for practical reasons, therefore, some continuous operations have been replaced by fed batch process chandel et al. 134 table 2. various raw materials for ethanol production. raw material pretreatment and fermentation microorganism reference saccharification conditions sugarcane baggase dilute acid hydrolysis batch c. shehatae ncim3501 chandel et al., 2006b wheat straw dilute acid, enzymatic ssf, shf e. coli fbr5 saha et al., 2005 hydrolysis rice straw auto hydrolysis batch c. shehatae ncim3501 abbi et al., 1996 sorghum straw steam explosion, ssf kluyveromyces marxianus ballesteros et al., 2004 enzymatic cect10875 corn stover steam, enzymatic fedbatch s. cereviseae tmb3400 ohgren et al., 2006 barley husk steam, enzymatic ssf s. cereviseae palmarola et al, 2005 sun flower stalk steam, enzymatic batch s. cereviseae var ellipsoideus sharma et al., 2002 sugarcane leaves alkaline h2o2 ssf s. cereviseae nrrl-y-132 krishna et al., 2001 wheat bran dilute acid, enzymatic batch s. cereviseae palmarola et al, 2005 hydrolysis ground nut shell acid hydrolysis batch s. cereviseae akpan et al., 2005 alfalfa fibers liquid hot water ssf, shf c. shehatae fpl-702 sreenath et al., 2001 aspen acid hydrolysis continuous, immobilized p. stipitis r parekh et al., 1987 cells saw dust acid hydrolysis batch, continuous upclostridium liu et al., 1988 flow reactors thermosaccharolyticum atcc 31925 pine acid hydrolysis continuous stirred tank p. stipitis nrrl-1724 qureshi et al., 1991 reactor, immobilized cells poplar steam explosion, ssf, shf s. cerevisiae cantarella et al., 2004 enzymatic birch acid hydrolysate batch s. cerevisiae johanssen et al., 2001 spruce dilute acid hydrolysis fed batch s. cerevisiae taherzadeh., 1999 willow steam batch e. coli k011 olsson et al., 1995 paja brava dilute acid hydrolysis, batch c. shehatae, p. stipitis, sanchez et al., 2004 two stage pachysolen tannophilus eicchornia crassipes dilute acid hydrolysis batch p. stipitis nigam, 2002 saccharum dilute acid hydrolysis, batch, fed batch p. stipitis ncim 3498 gupta, 2006 spontaneum enzymatic cassava starch starch liquifaction batch, continuous cos. diastaticus zymomonas mobilis amutha and immobilized cells gunashekhran, 2001 apple pomace ssf s. cerevisiae atcc 24702 ngadi and correial, 1992 pine apple canary juice extraction continuous, immobilized s. cereviseae atcc 24553 nigam, 2000 waste cells banana pulp waste juice extraction continuous, s. uvarum ncim culture 3528 joshi et al., 2001 cell recycles. finger millet high gravity fermentation s. cerevisiae reddy and reddy, 2006 (eleusine corcana flour ) municipal solid acid pretraetment batch s. cerevisiae mtui and nakamura, waste (msw) 2005 news print acid hydrolysate batch e. coli b (ploi297) lawford and rousseau, 1993 industrial waste ssf k. marxianus, s. cereviseae kadar et al., 2004 (schugerl, 1987). keeping the low feed rate of substrate solution containing high concentration of fermentation inhibitors such as furfural, hydroxymethyl furfural and phenolics, the inhibitory effect of these compounds to yeast can be reduced. complete fermentation of an acid hydrolysate of spruce, which was strongly inhibiting in batch fermentation, has been achieved without any detoxification treatment (taherzadeh, 1999). the productivity 135 afr. j. environ. econ. manage. in fed batch fermentation is limited by the feed rate which, in turn, is limited by the cell mass concentration. the specific ethanol productivity has also been reported to decrease with increasing cell mass concentration (lee and chang, 1987; palmqvist et al., 1996). ideally, the cell density should be kept at a level providing maximum ethanol productivity and yield. continuous fermentation continuous fermentation can be performed in different kind of bioreactors – stirred tank reactors (single or series) or plug flow reactors. continuous fermentation often gives a higher productivity than batch fermentation, but at low dilution rates which offers the highest productivities. alexender et al., (1989) studied the effect of shift in temperature and aeration in steady state continuous culture of c. shehatae to determine the effects of ethanol on xylose metabolism. the accu-mulation of ethanol exerted a delayed inhibitory effect on the specific rate of substrate utilization. continuous operation offers ease of control and is less labor intensive than batch operation. however contamination is more serious in this operation. since the process must be interrupted, all the equipments must be cleaned, and the operation started again with the growth of new inoculum. the continuous process eliminates much of the unproductive time associated with cleaning, recharging, adjustment of media and sterilization. a high cell density of microbes in the continuous fermenter is locked in the exponential phase, which allows high productivity and overall short processsing of 4 6 h as compared to the conventional batch fermentation (24 60 h). this results in substantial savings in labour and minimizes investment costs by achieving a given production level with a much smaller plant. immobilized cells a limitation to continuous fermentation is the difficulty of maintaining high cell concentration in the fermenter. the use of immobilized cells circumvents this difficulty. immobilization by adhesion to a surface (electrostatic or covalent), entrapment in polymeric matrices or retention by membranes has been successful for ethanol production from hexoses (godia et al., 1987). the applications of immobilized cells have made a significant advance in fuel ethanol production technology. immobilized cells offer rapid fermentation rates with high productivity that is, large fermenter volumes of mash put through per day, without risk of cell washout. in continuous fermentation, the direct immobilization of intact cells helps to retain cells during transfer of broth into collecting vessel. moreover, the loss of intracellular enzyme activity can be kept to a minimum level by avoiding the removal of cells from downstream products (najafpour, 1990). immobilization of microbial cells for fermentation has been developed to eliminate inhibition caused by high concentration of substrate and product and also to enhance ethanol productivity and yield. abbi et al., (1996) observed that the rate of sugar consumption by immobilized cells of c. shehatae ncl-3501 was slightly lower than that of free cells, thus leading to higher ethanol production. when microorganisms are attached to solid supports, fluid viscosity is lower which contributes to better mixing and mass transfer in the system. the work on ethanol production in an immobilized cell reactor (icr) showed that ethanol production using z. mobilis was doubled. amutha and gunasekaran (2001) reported ethanol production, 46.7 g/l from 150 g/l liquefied cassava starch from co-immobilized cells of saccharomyces diastaticus and z. mobilis. yamada et al. (2002) successfully used recombinant z. mobilis with high sugar concentration (12-15%) and further observed the significant role of increased biomass concentration in bioreactor performance for the improved ethanol production. a repeated batch fermentation system was used to produce ethanol using an immobilized osmotolerant s. cereviseae, in which ethanol concentration as high as 93 g/l was recorded at 200 g/l glucose concentration (sree et al., 2000). nigam (2000) has reported that the ethanol production rate as high as 42.8 g/l/h was achieved from the fermentation of pineapple canary derived sugars by s. cereviseae atcc 24553. recycling of process stream in an environmentally sustainable process, the use of fresh water, the amount of wastewater and the energy consumption must be minimized. the water consumption is decreased by recirculating process streams for use in the washing and hydrolysis steps (palmqvist and hahnhagerdal, 2000). recirculating part of the dilute ethanol stream from the fermenter can increase the ethanol concentration in the feed to the distillation stage. however, computer simulations have shown that recirculation of streams leads to the accumulation of nonvolatile inhibitory compounds (galbe and zacchi, 1992; palmqvist et al., 1996). to increase the ethanol productivity, cell recycling has been employed by several workers (fein et al., 1984; maleszka et al., 1981), while retaining the simplicity of the batch process. cell recycling generally does not increase the sugar consumption or ethanol production but the time required for the fermentation can be reduced by 60 70%. schneider (1989) observed a reduction in ethanol production after third cell cycle and suggested the decrease in ethanol production was due to the limitations of oxygen and sugar as a result of an increase in cell density. economics of ethanol production technologies to be competitive, and find economic acceptance, the cost for bioconversion of biomass to liquid fuel must be chandel et al. 136 lower than the current gasoline prices (wayman and parekh, 1990; subramanian et al., 2005). it seems how-ever; now much more attainable because of increasing efforts of researchers working towards improvisation in the efficiency of biomass conversion technologies (vertes et al., 2006). however there is still huge scope to bring down the cost of biomass-to-ethanol conversion. the cost of feedstock and cellulolytic enzymes are two important parameters for low cost ethanol production. biomass feedstock cost represents around 40% of the ethanol production cost (hamelinck et al., 2005). an analysis of the potential of bioethanol in short and long term (2030) in terms of performance, key technologies and economic aspects such as cost per kilometer driven has been conducted recently by hamelinck and faaij (2006). in this analysis, the production cost of bioethanol was found to be within the range of 16-22 /gjhhv (euro/giga joules high heating value) at present and down to 13 /gjhhv in future (2030). the feedstock cost is major parameter influencing the ethanol production cost at a rate of 2-3 /gj fuel. employing integrated approaches using the larger industrial facilities by integrated action plan along with cheap feedstock and potent cellulases could make the process more economically viable (sun and cheng, 2002; dien et al., 2006) securing long supply of energy sources requires not only that existing fuel resources be utilized as economically as possible along with their diversification uses. keeping this point of view, bioethanol is identified and portrayed as the entity for ensuring energy security in future fuel interests and global requirements. the choice of feedstock for ethanol production depends upon its availability and the ongoing uses. for example, agroresidues such as wheat straw, sorghum and barley straw are not preferable for bioethanol production due to their use as animal fodder. on the contrary, agroresidues like sugarcane bagasse, rice straw, rice bran, groundnut shell, corn stover, brassica carniata stalks and soyabean stalks etc can be used directly because these sources are not preferably used as fodder for livestock. some dedicated energy sources like damaged rice and sorghum grains (suresh et al., 1999), sunflower stalks and hulls (sharma et al., 2000), eicchornia crassipies (nigam, 2003), p. brava (sanchez et al., 2004), alfalfa fibers (sreenath et al., 2001), residual starch and crushed wheat grains (davis et al., 2006), agro waste (campo et al., 2006) and saccharum spontaneum (gupta, 2006) are more feasible sources for bioethanol production. also, organic waste and municipal solid waste (msw), which contain significant amount of cellulose could be cost economic friendly and solve the problem of solid waste storage and management. in india, department of biotechnology, govt. of india funded a nationwide research project towards the use of selective weeds like lantana camara, prosopis juliflora and fruit or vegetable waste into ethanol conversion due to their vast abundance, low cost and rich in fermentable carbohydrates. an important factor for reducing the cost of bioethanol production is to use larger industrial facilities rather than smaller ones. ward and singh (2002) also suggested the integrated approach (process engineering, fermentation and enzyme and metabolic engineering) could improve the ethanol production economics. by increasing the plant size, the investment per unit output of product falls off, a ten-fold increase in size reducing the unit cost to less than one-half and thereby reducing unit capital cost charges and conversion cost reducing profitability (wayman and parekh, 1990; henke et al., 2006). to further improve the economy of ethanol production, energy integration of the ethanol production, to already existing plants such as pulp and paper plants is necessary. o’ o’boyle et al. (1991) reported that the cost of producing ethanol from pine with a diluted acid hydrolysate process, was estimated to be 3.22 sek l -1 in a stand alone plant in comparison to 2.54 sek l -1 with an integrated plant. they projected that the cost of bioethanol can be reduced from us$ 1.22 per liter to about us $ 0.31 per liter on the basis of continuous improvement in pretreatment of biomass, enzyme application and fermentation. aristidou and penttila (2000) reported that the total cost of ethanol will be dropped from more than $1.0 per litre to ~ $0.3-0.5 per litre, with a projected cost of less than $0.25 per litre in the near future. wilke et al. (1981) has made the first effort to analyse the cost of the conversion of biomass to ethanol process based on a shf operation and concluded that neat ethanol could compete with gasoline at the oil prices at $20 to $30 per barrel. foody (1988) has emphasized the importance of improvement in cost effective cellulases production and outlined the potential for bringing down the price of bioethanol from 25-55 cents to 10-28 cents per liter. subsequently, wright (1988) and hinman et al. (1992) evaluated the benefits of ssf process over to shf technology and reported the cost based on economic evaluation of bioethanol keeping view the ssf mode of operation. wooly et al. (1999) explained the further economic analysis of bioethanol ( $ 0.78 per gallon) and suggested a projected cost of as low as $ 0.20 per liter by 2015 if enzymatic processing and biomass improvement targets are met. the projected cost of ethanol production from cellulosic biomass as per the earlier estimates ($4.63/gallon in 1980) has been reduced by almost a factor of four ($1.22/gallon) over the last 20 years (wyman, 1999; wyman, 2001). however, kadam et al. (2000) reported that ethanol production cost can be achieved at $ 1.20 per liter by using two-stage dilute acid hydrolysis process. krishnan et al. (2000) worked out on economics of ethanol production from dry-milled corn starch in fluidized–bed reactors using immobilized z. mobilis cells. they analysed the cost of ethanol for 15 million gal/year production plant 137 afr. j. environ. econ. manage. using aspen plus (aspen technology, cambridge; ma) process simulation software and concluded that the operating cost savings of ethanol production in the range of 1.1 3.1 cents/gallon. kwaiatkowski and coworkers (2006) developed a model for cost evaluation of ethanol production from 40 million gal/year ethanol producing facility using corn dry-grind process technology. the model was developed using super pro designer r software and data collected from ethanol producers, technology suppliers, equipment manufactures and engineers working in the different industries. the cost of ethanol was found to be increased from us$ 0.235/l to us$ 0.365/l as the price of corn increased from us$ 0.071 to us$ 0.125 /kg. the bioconversion of pentosans and hexosans from lignocellulosic biomass to ethanol need to be achieved with the maximum efficiencies in terms of higher yield and improved productivity to make the biomass-to-etha-nol process economical. the economics of the ethanol process is determined by the cost of sugar. the average biomass cost amounts to ~$0.06 per kg of sugar, or a contribution to the feedstock costs for ethanol production of as low as $0.10 per liter (aristidou and penttila, 2000). wingren et al. (2003) evaluated the shf and ssf economic using cellulase enzymes in both configurations with ssf being less expensive by about 10%; and estimated the ethanol production cost of 0.56 – 0.67 $/l. later, wingren et al., 2004 studied the effect of reduction in yeast and enzyme concentration in ssf process and concluded final ethanol production cost 4.80 sek/l (2.34 us$/gal). according to the national renewable energy laboratory (nrel, colarado, usa) estimations, ethanol production cost of 20 cents per litre is possible in another 15 years from lignocellulose biomass employing designer cellulases and sscf (simultaneous saccharification and co-fermentation) process (ghose and ghose, 2003). however, in both the process, the use of cellulase makes the process cost effective (mielenz, 2001; alzate et al., 2005; gray et al., 2006). according to the analysis of us doe (us department of energy), if the enzyme cost can be brought for less than 10 cents per gallon of ethanol the cost of making ethanol could drop as low as 75 cents / gallon (griffith and atlas, 2005). apart from focusing the economics of cellulase production cost, several studies are being carried out to improve the ethanol production by improving acid hydrolysis process. luong and tseng (1984) evaluated the technoeconomics of ethanol production under continuous culture using immobilized cells of z. mobilis using plug-flow reactor. they found this technology economically attractive and finally concluded that at least 4 cents/gal of ethanol could be saved using immobilized cells rather than the conventional batch system. they further suggested that by switching from batch to immobilized processing; the fixed capital investment is substantially reduced, thus increasing the profitability of ethanol production by fermentation. von sivers et al. (1994) analysed the cost economics of ethanol producti on (48 cents/gallon) from detoxified willow hemicellulosic hydrolysate using recombinant e. coli k011. zacchi and axelsson (1989) suggested preconcentrating dilute sugar solution using reverse osmosis is economically feasible to getting high ethanol concentration in fermented broth. cysewki and wilke (1976) described cell recycle and vacuum fermentation processes for continuous ethanol production on a production capacity of 78,000 gal ethanol / day employing molasses as the fermentation substrate and estimated ethanol production cost 82.3 and 80.6 cent/gal, for the cell recycle and vacuum processes, respectively. more recently zhang (2006) analyzed the cost economics of ethanol production from a smallsize lignocellulose refinery with a capacity of 100 tones per day producing approximately 3 million gallons of ethanol plus coproducts. he estimated the cost of ethanol production ~$1.00-1.20 per gallon. the distillation cost of per unit amount of ethanol produced is substantially higher at low ethanol concentrations, the researchers have dealt with the idea of concentrating sugar solutions prior to fermentation (cyweski et al., 1976; oh et al., 2000; iraj et al., 2002). ethanol distillation cost can be further improved by using membrane distillation process. it has the lowest operational cost, flexible, simple to use and is easy to maintain. it is most efficient and cost effective option among the available distillation processes (gonsalves, 2006). ethanol and environment ethanol represents closed carbon dioxide cycle because after burning of ethanol, the released carbon dioxide is recycled back into plant material because plants use co2 to synthesize cellulose during photosynthesis cycle (wyman, 1999; chandel et al., 2006a). ethanol production process only uses energy from renewable energy sources; no net carbon dioxide is added to the atmosphere, making ethanol an environmentally beneficial energy source (figure 5). in addition, the toxicity of the exhaust emissions from ethanol is lower than that of petroleum sources (wyman and hinman, 1990). ethanol derived from biomass is the only liquid transportation fuel that does not contribute to the green house gas effect (foody, 1988). as energy demand increases the global supply of fossil fuels cause harm to human health and contributes to the green house gas (ghg) emission. hahn-hagerdal (2006) alarmed to the society by seeing the security of oil supply and the negative impact of the fossil fuel on the environment, particularly on ghg emissions. the reduction of ghg pollution is the main advantage of utilizing biomass conversion into ethanol (demirbas, 2007). ethanol contains 35% oxygen that helps complete combustion of fuel and thus reduces particulate emission that pose health hazard to living beings. a study conducted by bang-quan et al. (2003) on the ethanol blended diesel (e10 and e30) figure 5. ethanol represents closed co2 cycle. combustion at different loads found that addition of ethanol to diesel fuel simultaneously decreases cetane number, high heating value, aromatics fractions and kinematic viscosity of ethanol blended diesel fuels and changes distillation temperatures. these factors lead to the complete burning of ethanol and less emissions. with its ability to reduce ozone precursors by 20 30%, bioethanol can play a significant role in reducing the harmful gasses in metro cities worldwide. ethanol blended diesel (e-15) causes the 41% reduction in particulate matter and 5% nox emission (subramanian et al., 2005; chan-del et al., 2006a). one of the disadvantage in using ethanol as fuel is that aldehyde predominantly acetalde-hydes emissions are higher than those of gasoline. how-ever acetaldehydes emissions generate less adverse health effects in comparison to formaldehydes emitted from gasoline engines (gonsalves, 2006). environmental impact of bioethanol production technologies and their life-cycle assessment (lca) life-cycle assessment (lca) is a conceptual framework and methodology for the assessment of environmental impacts of product systems on a cradle-to-grave basis (graedel, 1999; tan et al., 2002). analysis of a system under lca encompasses the extraction of raw materials and energy resources from the environment, the conversion of these resources into the desired products, the utilization of the product by the consumer, and finally the disposal, reuse, or recycle of the product after its service life (tan et al., 2002). the lca approach is an effective way to introduce environmental considerations in process and product design or selection (azapagic, 1999). based on life cycle assessment (lca) studies, ethanol production technologies can be compared. energy production and utilization cycles based on cellulosic biomass have nearzero green house gas emissions on a life cycle basis (lynd et al., 1991). biomass utilization into ethanol production offer environmental benefits in terms of nonrenewable energy consumption and global warming impact. kim and dale (2005) studied lca emphasizing corn and soyabean production and their utilization into bioethanol and biodiesel production and concluded that both the biofuels have environmental benefits in terms of nonrenewable energy consumption and global warming impact. however biomass utilization into ethanol also tends to increase acidification and eutrophication, primarily because large nitrogen, phosphorus are released after cultivation of crops. lechon et al. (2005) studied the lca of ethanol production from wheat and barley grain and found that barley is a better option than wheat in terms of fulfillment of the green house gas emissions. chandel et al. 138 139 afr. j. environ. econ. manage. figure 6. coordinated action for improvement of biomass to ethanol and its long term benefits. in an extensive study by kadam (2000), lca of acid and enzymatic hydrolysis was compared. all environmental flows were examined from the product life cycle, its production and extraction from raw materials through intermediate conversion process, transportation, distribution and use. dilute acid process was found better than the enzyme process in terms of greenhouse gas potential, natural resource depletion, acidification potential and eutrophication potential (kadam, 2002). the reason is dilute acid process sends a much higher proportion of biomass to the boiler for electricity production, which in turn offsets large amounts of emissions (kadam, 2000). conversely the concentrated acid process is a net consumer of energy in terms of high acid load and reaction temperature, results in very high values for green house gas (ghg) effect and other impact parameters (kadam, 1999). kemppainen and shonnard (2005) compared the energy consumption and environmental impact for ethanol production using timber wood and recycled news print. the news print conversion into ethanol has a slightly lower overall composite environmental index compared to the timber process. however ethanol production from timber takes less energy, electricity and produces fewer emissions. a study conducted by hu et al. (2004) revealed that the e-85 fueled vehicle is better vehicle than the gasoline fueled car by balancing of all the 3e”s the energy, environmental and economic aspects. e-85 fuelled ffv (fossil fuelled vehicle) is about 15% higher efficient when compared to gasoline fuelled car. it also lowers the pollutant emission viz. particulate matter, co2, co, nox emission than gasoline fuelled car. e-85 fuelled vehicle is higher in total energy consumption and a good combined energy indicator. this was also in agreement with the recent life cycle-based (well to wheel) studies of fuel / propulsion alternatives for light–duty vehicles with a focus on lignocelluloses derived fuel ethanol by reducing 86% lower life cycle green house gas emissions as compared to the gasoline (fleming et al., 2006). tonan et al. (2006) has discussed the integrated assessment of energy conversion processes by evaluating the thermodynamic, economic and environmental parameters and found that water and air emissions of the plant producing ethanol are relatively low. the tansformity of chandel et al. 140 ethanol (1.32 x 10 5 sej/j) is quite high if compared to that of fossil fuel (5.4 x 10 4 sej/j). this is even when bioethanol production is driven by a large amount of nonrenewable inputs (fertilizer, fuel, machinery). conclusion in spite of laboratory based bioethanol success stories, the production of fuel ethanol at plant scale still remains a challenging issue. a positive solution to this issue could bring economic advantage not only for fuel and power industry, but also benefit the environmental rehabilitation and balance issues and cause. worldwide, there is only one company, iogen corporation, canada (http://www.iogen.ca), produce bioethanol at commercial scale using wheat straw and corn stover. in india, despite plentiful availability of biomass, there is no commercial ethanol production plant from lingocelluloses. the key to the establishment of a commercial bioethanol production facility and the reduction in capital thereof, resulting in lessening of operating costs from each of the units of operations will be an achievement par standards of excellence and utility! industry attention, not just the accolades is required for searching the answers to the fast paced fuel drain phenomena threatening to takeover into as a major crisis or even worse an economic depression by the end of 21 st century! for a flourishing bioethanol industry, government support is critical in correcting tax anomalies, exemption from excise and sales tax, deregulation of feedstock and its pricing and encouraging pilot projects and r&d work on bioethanol. advances in pretreatment by acid catalyzed hemicellulose hydrolysis or employing an integrated approach in the form of consolidated bioprocessing with application of novel, tailored cocktails of enzymes for the cellulose breakdown coupled with the recent development of genetically engineered microorganism those ferment all possible sugars in biomass to ethanol at high productivity are the major key factors to make bioethanol program successful at commercial scale (figure 6). the other important aspect by deploying the bioethanol option is its benefit to the environment. ethanol is one of the best tools to fight vehicular pollution; its clean burning reduces the harmful gasses and particulate emissions that pose health hazard. the implementation of bioethanol policy can be helpful in improving in envi-ronment and rural economic development with sustainable agricultural practices and enhancement of biomass feedstock conscious usage towards the bioethanol industry will bring up the new age farmer into the limelight and horizon of activities and threshold of business to become renewed with options to deal better in life! 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ecological, political and technological issues into economic development programs: key to sustainable development of human society rajiv k. sinha 1 *, brijalkumar soni 1 and binod shankar 2 1 school of engineering (environment), griffith university, nathan campus, brisbane, qld-4116, australia. 2 department of environment and water management, a.n. college, patna, india. accepted 6 may, 2013 we need to plan for ‘development without destruction’ and manage our environment based on the ethical principle of social equality, economic prosperity with ecological security to achieve the goals of sustainable development. environmental management and economic development programs should go hand in hand for achieving sustainability in global human society. changes in the way we develop our economy, eat and drink, live and move, use and discard (as waste) the earth’s resources, enjoy our lifestyle are needed to be changed quickly to bring us back into balance with our life support systems on earth. we have also to overcome the ‘greed’ of having more and be ‘contented’ after our ‘needs’ are fulfilled. greed based society can never be sustainable. the key to growing sustainably is not to produce less but to produce differently, in a way which is environmentally friendly and compatible, that is, by embracing the philosophy of ‘cleaner production’; not to consume less but to consume judiciously and efficiently within the regenerative capacity of the earth ecosystems and with minimum waste generation. key words: technological, social, economic, ecological and political considerations, good health, social equity, eradication of poverty. introduction major environmental issues affecting human future and sustainability on earth environmental problems of major concern are local, regional/national and global. the local concerns are air, water and noise pollution, declining groundwater table and increasing shortage of potable water, chemical spills and contaminated sites (land), acid sulfate soil, indoor air pollution and household hazardous wastes, urban sprawl and congestion, increasing health risks of urban residents, waste landfills and toxic emissions, solid waste (specially plastic waste) and sewage, green-land clearing and threatened species. the regional concerns are rural *corresponding author. e-mail: rajiv.sinha@griffith.edu.au. decline, declining rain and depleting natural water resources, increasing soil salinity, increasing natural and man-made disasters, disposal of chemical and radioactive wastes, ocean oil spills and marine pollution, degrading coastal ecosystems, acid rains etc. the global environmental concerns are threat of global warming and climate change, stratospheric ozone depletion, deforestation and biodiversity erosion, overpopulation and resource depletion especially in poor developing countries (sinha, 2006). vanishing water resources on earth: destroying the elixir of life out of the total water on earth, only 2.5% are freshwater, 97.5% are seawater and only less than 1% is useful for sinha et al. 033 human use and consumption which are also being destroyed by human wastes and chemicals. underground water table is rapidly falling throughout the world. within 25 years, half of the world’s population could face hardship in finding enough freshwater for drinking, sanitation and food production. about 3 million litres of water is needed to produce 1 ha of corn; about 12 to 20 million litres to produce 1 ha of rice; about 250 l to produce 1 kg of wheat; about 25,000 l to produce 1 kg of meat; about 50 l to produce 1 l of whisky; about 250 l to produce 1 kg of steel and about 18,000 l to refine 1 ton of petroleum. about 45 industrial chemicals have been found in surface water. they are ‘endocrine distruptors’ in very low-parts-per billion. the cost of providing safe drinking water and sanitation to everyone in the world by 2025 will be us $ 180 billion per year. chemicals in the breathing air: destroying the source of life on earth several millions tones of gases, carbon monoxide (about 106 million tonnes), carbon dioxide (4550 mt), sulfur dioxide (90 mt), oxides of nitrogen (60 mt), methane (84 mt), hydrocarbons (47 mt), cfc and halons (1 mt) and suspended particulate matter (30 mt) enter into our atmosphere every year from our industries and automobiles. diesel vehicles emit over 100 microparticles several of which are carcinogenic. some 189 hazardous air pollutants (haps) have been identified in the atmosphere. unep estimates that over 3 million people in world die every year from air pollution related diseases and the non-cigarette smoker lung cancer rate due to outdoor air pollution in world today is estimated to about 2000 cases per year. according to who, coal power plants in the u.s. cuts short nearly 24,000 lives, including 2,800 from lung cancer and nearly 38,200 from heart attacks each year. degrading and eroding soil mantle: destroying the food base on earth billions of tones of top soil (the fertile layer) are eroded away every year, being washed away into the sea or carried away with wind converting into wasteland. every year, nearly 27 million hectares or say, 47 ha min -1 , of valuable fertile land are lost by desertification. every minute a chunk of ‘fertile agricultural land’ of the size of tennis court is being converted into wasteland. over the last two decades, the world has lost some 500 million metric tons of topsoil. only the ‘top thin layer’ of the soil with humus is vital to grow food and is sustaining the entire civilization. formation of just 1 cm of soil from parent rock take from 100 to 1,000 years and 2.5 cm of topsoil can take from 100 to 2,500 years. fao has warned that the world's soil was degrading so fast that in little more than 30 years it might no longer be able to feed its growing population. depleting forest and biodiversity: destroying the protector of life on earth each year, around 17 to 18 million hectares of tropical forests rich in species diversity are cleared for timber, paper and fuel wood, and for fodder growing to export to meat producing industries in europe and america. every day a minimum of 3 (some put it 30) species of life is permanently disappearing from the face of earth and at current rate of habitat destruction it can become 3 species every hour in coming years. disappearance of 1 plant species may eventually lead to the extinction of up to 30 insect and animal species in the food chain as they depend upon plants for survival. meat eating society is taking heavy toll on our biodiversity. the same amount of plant food that would feed 1.5 billion pure vegetarians would only feed 210 million meat eating people. each time we take a medicine; there is one chance in two that our purchases owe its origin from wild species. a number of them are ‘life-saving’ medicine. besides green plants are the main ‘source of life sustaining oxygen in air’ and ‘sink of greenhouse gas co2’ on earth. piling toxic chemicals on earth: the demons of development and inducer of deadly human diseases worldwide about 80 to 100,000 chemicals are in use every day in our industries and other developmental activities and some 1000 new chemicals are added each year. there are some 861 neuro-toxic chemicals in use in our cosmetics, perfumes and toiletries. the deadly chemicals ddt and pcbs have reached even up to the poles. a relationship between ‘chemicals and cancer’ is scientifically proved and women are more vulnerable. according to unep and who, some 25 million farmers and agricultural workers are poisoned by chemical pesticides every year and nearly 3 million people suffer from ‘acute pesticide poisoning’ and some 10 to 20 thousand people die every year from it in both the developed and the developing countries. studies indicate that there is significant amount of ‘residual pesticides’ contaminating our food stuff long after they are taken away from farms for human consumption. vegetable samples were contaminated 100% with hch and 50% with ddt. us scientists predict that up to 20,000 americans may die of cancer, each year, due to the low levels of ‘residual pesticides’ in the chemically grown food (unep report, 1992). exposures to chemical pesticides are linked with serious diseases and developmental disorders like ‘nervous system disorders’, ‘immune system suppression’, breast and other cancers’ ‘reproductive damages’, ‘impairment of brain development in children’ 034 afr. j. environ. econ. manage. and ‘disruption of hormonal systems’ rising greenhouse gases inducing global warming and climate change: invitation to severe natural disasters co2, the major greenhouse gas inducing global warming was 280 ppm in the pre-industrial times and now stands at 370 ppm, 30% higher. it is currently rising by 0.5% every year. powerful greenhouse gases e.g. methane and nitrous oxide are emitted from solid waste management programs by composting or more from waste landfills. molecule to molecule, ch4 is 20 to 25 times more powerful and n2o is 296 to 310 times more powerful ghg than carbon dioxide (co2). every 24 h, human activity on earth generates some 16 million tons of greenhouse gas co2 and release into the atmosphere. coal power plant gives out about 800 to 1000 g of co2 for every unit (kwh) of electricity produced. in one year, an average car emits 4.3 tons of co2. agriculture has also been responsible for huge emissions of greenhouse gases and induction of global warming. of the increase of atmospheric carbon over the last 150 years, about a third (33.3%) is thought to have come from agriculture. over the last century, the world has warmed between 0.3 and 0.6°c. if emission of all the ghg are not arrested the world will on average be 1.3°c warmer by 2020. global warming disturb rainfall patterns, ‘suppress human immune system’ and induce natural disasters. mounting human wastes on earth: poisoning the soil, air and water msw is mounting on earth everywhere. in u.s., each sunset sees a new mountain of nearly 410,000 tons of garbage. the european union throws away an estimated 2 billion tones of msw each year. the character and composition of msw are changing in modern technological society with the non-biodegradable ‘synthetic material’ coming into existence. biomedical waste constitute considerable portion of msw, 10% is ‘infectious’ and 5% is non-infectious but potentially toxic and radioactive. several toxic chemicals are used in modern homes, resulting into generation of household hazardous waste, which are mixed and disposed with the msw ending up in landfills with serious consequences for environment and society. the ‘electronic waste’ has become serious problem. it is like ‘tsunami’ of ‘e-waste’ in world. it is virtually a chemical waste mixed with general msw ending up in landfills. waste landfills emit more powerful greenhouse gases (methane and nitrous oxides) and toxic trace gases like ‘xylene’ and ‘toluene’ and toxic leachate that can contaminate groundwater. in 2005 waste landfills in australia emitted some 17 million tons co2-e (equivalent) of greenhouse gas equivalent to the emissions from 4 million cars. every 1 kg of solid waste diverted from landfills prevents 1 kg of greenhouse gas emission equivalent to co2. depleting stratospheric ozone shield: exposing mankind to radiation hazards hole in the ozone shield in the stratosphere over the antarctica is growing larger and deeper, exposing man and other species to increased levels of harmful ub-v radiation. some 66,000 tones of ozone depleting chemicals are released into the environment every year due to human activity. increased ub-v radiation can cause suppression of human immune system making people vulnerable to infectious diseases. it can cause non-melanoma skin cancers and blindness from juvenile cataracts worldwide; vulnerability of the human society on earth – how sustainable is our future? n-nitrosodimethylamine (ndma), a principal ingredient in rocket fuel and methyl tertiary butyl ether (mtbe), a gasoline additive were discovered in surface and ground water sources; thousands of kilometers away from where they were used. ddt and pcbs were found on poles, thousands of kilometers away from where they were produced; radioactive isotopes strontium-90 (sr 90 ) and cesium-137 (cs 137 ) which are routine emissions from all nuclear power plants were found in the bone marrow of children in india far away from the sources of their emissions. all these chemical and radioactive contaminants followed the air routes to reach those distant destinations. from the atmosphere they precipitated down to earth and entered into the human ecosystem. this shows how vulnerable we have become in the wake of material development and also pose a major question on how much sustainable is our future on earth (meadows et al., 1992). global movement for sustainability first un conference on human environment, stockholm, sweden, 1972 the first ever world conference on human environment was held in stockholm in june 1972 where representatives from more than 70 countries participated and pledged to save the environment. this may be regarded as the ‘1 st earth summit’. the conference was chaired by mrs. gro harlem bruntdland the then prime minister of norway who was later entrusted with the task of forming the ‘world commission on environment and development’ (wced) in 1987 where she conceived the sinha et al. 035 term ‘sustainable development’. at stockholm, the world leaders declared – “man is both creature and moulder of his environment, which gives him physical sustenance and affords him the opportunity for intellectual, moral, social and spiritual growth. both aspects of man’s environment, the natural and the man-made, are essential to his well-being and to the enjoyment of basic human rights, the right to life itself”. bruntdland commission report on sustainable development (1987) the report of the ‘world commission on environment and development’ (wced) was published as ‘our common future’ (wced, 1987). it redefined the concept of development which should encompass three components: 1. a systems of socio-economic development to meet the ‘needs’ (but not the ‘greed’) of the present generation without compromising with the abilities of the future generations to meet their own needs. 2. a system of stable socio-economic and ecological development that should improve the total quality of all life (human beings, plants and animals) on earth now and in the future too, while maintaining the social and ecological integrity (natural and man-made ecosystems) of the earth upon which all life depends. 3. a system of socio-economic development which can provide good quality of life to all the people (rich and poor, men and women, adults and children) born on earth, while protecting their basic life-support systems (air, water, soil, flora and fauna) and also safely disposing all the wastes (domestic, commercial and industrial) generated by them (label et al., 1987, goodland and serafy, 1991). un conference on environment and development, rio de janeiro, brazil, 1992 the un conference on environment and development was held at rio de janeiro, brazil, in 1992. this was the ‘2 nd earth summit’ organized 20 years after stockholm and was participated by 172 countries (more than twice that participated at stockholm). ‘environment and sustainability’ and ‘sustainable development’ was the focus of discussion. the world leaders declared – “human beings are the center of concerns for sustainable development. they are entitled to a healthy and productive life in harmony with nature”. the agenda 21 (agenda for the 21 st century) was adopted at unced. it was the blueprint for global sustainable development. agenda 21, pronounced that “humanity stands at defining moment in history. we are confronted with a perpetuation of disparities between and within nations, a worsening of poverty, ill health and illiteracy, and the continuing deterioration of natural ecosystems on which we depend for our well-being”. however, integration of environment and development concerns and greater attention to them will lead to the fulfillment of basic needs, improved living standards for all, better protected and managed ecosystems and a safer more prosperous future. no nation can achieve this on its own but together we can in a global partnership for sustainable development’. agenda 21 cautioned that the growing population and poverty in the developing countries and the unsustainable pattern of consumption in the developed industrialized countries would thwart the spirit and pace of sustainable development throughout the world. for ‘environmental sustainability’, ‘socio-economic prosperity’ and ‘environmental literacy’ of the global human society, and ‘political stability’ throughout the world should be a precondition. poor and the deprived people, and the politically discriminated would violate all economic and ecological imperatives in order to survive (because survival is more important than sustainability) thus leading to unsustainability. highly educated can be ‘environmentally illiterate’ and fail to realize the importance of sustainability. 3 rd world summit on sustainable development (wssd), johannesburg, s.a., 2002 the wssd (2002) was held at johannesburg, south africa to take stock of the situation about the achievements made towards attaining sustainability in the field of human development during the last 10 years since the 2 nd earth summit in 1992. the task at johannesburg was to recapture the momentum of the movement for sustainability begun at stockholm (1972) and rio (1992). in the 10 years between rio (1992) and johannesburg (2002), critical environmental problems such as greenhouse gas emission (global warming), loss of old growth and primary forests (biodiversity erosion), ocean plunder and waste of resources (piling waste), lurched from bad to worse. on the socio-economic front, the rich and the powerful got richer and more powerful, while the poor became poorer and weaker. the concept of ‘sustainable development’ and the much lauded movement for sustainability remained on paper. these are some of the disheartening episodes of the efforts made towards achieving global human sustainability: 1. two billion people currently do not have access to modern energy services; 2. about than 1.1 billion people globally do not have access to safe drinking water. it is predicted that water supply will be the major constraints on sustainable development in the 21 st century. 3. about 2.4 billion people lack adequate and improved sanitation; 4. more than 1.2 billion people still live on less than 1 dollar (ir 40.0) a day, that is, much below the poverty line; 5. more than 3 million people die of air pollution, and the same number dies from diseases caused by unsafe and polluted water. the target of ‘health for all by the year 2000’ never became a reality. 6. new highly toxic chemicals’ e.g. nnitrosodimethylamine (a principal ingredient in rocket fuel), methyl tertiary butyl ether (a gasoline additive), and ‘acrylonitrile’ (used in textile industry) have appeared in surface and ground water; 7. half of the tropical rainforests and mangroves (treasure of pristine biodiversity) have already been lost; 8. about 75% of the marine fisheries have been fished to capacity; 9. in september 2000, the ozone hole over antarctica covered more than 28 million square kilometers; 10. some 75 billion tones of ‘top soil’ are eroding every year. around 2 billion hectares of soil, 15% of earth’s land is now classed as degraded (who, 1997; undp, 2004; steffen et al., 2004). report of the global environmental outlook (geo)-3 on sustainability the planet is at ‘critical crossroads’ concluded the unep’s ‘global environmental outlook 3’ report (geo-3). the study, collaboration between unep and some 1,000 individuals and 40 institutions around the world is the most authoritative assessment to date of where we (the homo sapiens) have been, where we have reached, and where we are likely to go. geo-3 shows how far the world has gone on the road to sustainable development since the rio earth summit 1992. it said that though the world has made great strides in placing environment on the global developmental agenda, the twin evils of ‘poverty’ (in the developing world) and the ‘excessive consumption’ (in the developed world) due to too much of ‘prosperity’ continue to put enormous pressure upon it. dire poverty and environmental degradation feed on each other. ironically, growing poverty all over world is the main stumbling block on the road to environmental protection and sustainable development (unep-geo, 2004-05). people’s mandate on sustainable development several opinion polls were conducted on the eve of johannesburg summit (wssd, 2002) by international agencies to know the views of people across world and assess their awareness on the question of environmental sustainability built up since the rio earth summit in 1992. market and opinion international (mori) polled in 30 countries containing two third of world’s population and found that 91% people in greece, above 60% in the u.s., germany, russia, france, italy, spain, japan, mexico, brazil, chile, the republic of korea and china, and about 54% in india wanted legal protection for the environment through legislative actions. some 69% people in u.k. agreed that environmental degradation especially waste and pollution is affecting their daily life. opinion poll by roper worldwide found that 39% people in these 30 countries were of the view that environmental protection and sustainable development was of paramount importance today. the percentage of people expressing this view was significantly higher in india, argentina, the philippines and germany. gallup polls made in the u.s. found that 57% americans were more concerned about pollution of rivers, lakes and streams while 29% cited fears about global warming. (yet the u.s. has not signed the kyoto protocol). in another poll, 65% americans saw erosion of biodiversity as the most serious problem facing the humanity. the mori millennium poll wanted to know from people which section of the society was mainly responsible for the environmental degradation and the responsibility for its repair and restoration. almost 6 in every 10 asserted that the ‘corporate sectors’ were mainly damaging the environment to make profit even at the cost of environment, and hence protection of environment was their moral responsibility. indians also said that the company’s and industries must bear responsibility of environmental repair. but in the u.s., a majority of people asserted that environmental protection was government’s core responsibility and 90% of them wanted information on companies environmental and social records. 49% of the europeans surveyed said that they would not buy a product made in a country with poor environmental and social standards (undp, 2003, 2004). opinion polls clearly show that people worldwide realize the importance of environmental protection and sustainable development for their existence and put the blame mainly on the corporate sectors specially the transnational corporations (tncs) for all the environmental evils. the strategies for sustainable development planning for sustainable development is like ‘preventing’ a disease to occur in the first place. as prevention reduces the chances of individual suffering from the disease, so does, environmental planning and management for the whole society. it would significantly reduce, if not completely prevent, the risk of environmental damage and the sufferings of the society caused due to it. at least, it will prevent any major ‘environmental disaster’ which struck the human society in the past (sinha, 1994). 036 afr. j. environ. econ. manage. sinha et al. 037 sustainable development will deliver social, economic and ecological benefits, for it will conserve resources, reduce waste, prevent loss of energy and protect human health. the world business council for sustainable development (wbcsd) was formed in 1995. it is a coalition of 120 international companies that have a shared commitment to protect the environment through cleaner production and waste minimization in industries (schmidheiny et al., 1997). seven pillars of sustainable development the new paradigm of development is not the game of economics alone. all issueseconomic, ecological, social (health), cultural (educational), legal (legislative), political and technological have to be merged into a collective decision making for sustainable development. they are mutually reinforcing. technology plays greater role as they drive development (axinn, 1996). earlier economy was at the center of decision-making. this assumed that all environmental problems could be solved if economy was sound. this has now become an obsolete theory. now ecology has to be at the center. we have to integrate ecological thinking into social and economic planning. the developmental activities have to be ‘economically viable’, ‘ecologically compatible’, ‘socially equitable’, ‘culturally acceptable’ and ‘politically justifiable’. then only it can be environmentally sustainable. this will require giving up the ‘culture of consumerism’, ‘producing fewer consumers that the earth can sustain and also achieving ‘equity in resource use and consumption’ across the world. over-consumerism and too much of prosperity in one part of the world, or overpopulation and poverty in other part, would thwart the spirit of sustainable development. the most important sustainability issue today is to save and protect the very life-support systems (air, water, food and soil) and the biodiversity, protect human health, arrest global warming and depletion of stratospheric ozone shield, arrest desertification, augment clean energy and material resources to continue and maintain the pace of development, and to safely dispose all the wastes generated by the society. what we need to sustain 1. the ecosystems and the accompanying biodiversity with the variety of species and their habitats; 2. the natural capital of earth e.g. the stock of productive soils, forest and the fresh water and all the nonrenewable resources by preventing their unsustainable use; 3. the ecological integrity of earth and the resilience of natural life-support systems by maintaining an adequate number of primary producers; 4. the social integrity of earth by maintaining an acceptable level of non-consumerist population (secondary consumers) within the ecological limits and the ‘carrying capacity’ of earth (iucn, wwf, unep, 1991). the technological perspectives for sustainable development: development of environmental technologies science and technology came as a ‘mixed blessing’ for mankind. it brought peace and prosperity, comfort and facility, health and wealth for mankind through rapid utilization of the natural resources. it provided all the basic amenities of life and fulfilled all the human aspirations – copious amount of energy to drive all developmental activities and provides comforts of life, a good and secured dwellings to live and durable clothes to wear, a rapid means of transport and quick means of communication, nutritious foods to eat, clean water to drink, prompt healthcare and sanitation facilities, a system of weather forecast and advance warning system for coping with natural disasters and genetic engineering for improving the economic value of useful plants and animal species. when used judiciously and legitimately for human development, science saved life and property, but when ‘misused’, it spelt disaster. technology practically transformed the ‘traditional human society’ which was more vulnerable to the vagaries of nature, more dependent for survival on nature, less adapted to survive against odds, to ‘modern human society’ which is less vulnerable to the vagaries of nature, more fit to survive in difficult situations, less dependent on nature for survival and more competent to manage their affairs. technology is the backbone and driving force of sustainable development. however, unfortunately some of the technologies of the early 20 th century proved to be a ‘curse in disguise’. they triggered the pace of economic development by indiscriminately using the scarce resources, and generated huge amount of waste and pollution undermining the very resource base upon which development was to be made. towards the end of the last century when human environment specially the lifesupport systems air, water, soil and the natural ecosystems started showing signs of degradation that the scientific community realized that something wrong was going with the existing technologies used in the development process. this necessitated the development of more ‘appropriate technologies’ for human development which has been termed as ‘green technologies’ or ‘sustainable technologies’ (adams, 2001). technological developments (environmental technologies) in the past decades and especially after the1980s have delivered spectacular improvements in the environmental quality, cleaner air and water, low 038 afr. j. environ. econ. manage. emission automobiles, less toxic and hazardous wastes, water and energy efficient homes and appliances etc. some of the remarkable technological achievements of the 20 th and 21 st century marching towards sustainability are: 1. a significant reduction in the air borne lead (pb) has been achieved by developing ‘lead free petrol’ and use of natural gas and ethanol as auto-fuel. 2. a considerable reduction in the emission of co, hc and nox by modification in the ic engines, by installation of ‘catalytic converters’, and introduction of direct fuel injection and ‘lean-burn combustion technologies’. 3. more fuel efficient, quieter and less polluting automobiles driven on environmentally benign auto-fuels like compressed natural gas (cng), liquidified petroleum gas (lpg) and ethanol, less body and wheel weight and aerodynamic bodies to induce less resistance to wind. hybrid-vehicles are also quiet and much less polluting. hydrogen fuel which is 4.5 times powerful than petrol with ‘zero emission’ (only water vapor) makes a big promise for a sustainable future. u.s., germany and china are ahead. bmw, germany has several fleets operated on hydrogen. iceland also has buses running on hydrogen fuel. 4. development of more energy efficient electrical appliances and instruments such as automatic lighting control system (alcs), compact fluorescent light bulbs, low voltage tungsten halogen and sodium lamps etc. they save electricity from 70 to 80%. modern acs, fridges, washing machines, dishwashers use 75% less energy than older models. reverse cycle ac (for cooling and heating) use 67% less electricity, rheem pump hot water system (using air to heat water) use only 60% energy. electric stove with fan forced oven are 30% more efficient than conventional electric stove. gas stoves are much more energy efficient and microwaves uses 55% less electricity. compact fluorescent lamps use 70 to 80% less electricity for same light with 8 times longer life and prevent emission of nearly a ton of ghg in its lifetime (energy efficient appliances and instruments have reduced the emission of greenhouse gas carbon dioxide (co2) in the same proportion). 5. development of eco-efficient water appliance. a significant reduction in the waste of potable water has been achieved by developing ‘automatic closing taps’, ‘water efficient showers’ and ‘dual-flushing cisterns’ in the bathrooms and toilets and development of ‘sprinkler and drip irrigation’ systems in agriculture. new bathing shower uses 9 to 16 l of water per minute as compared to 20 to 30 l used by inefficient showers. the dual-flush cistern saves 6 l of water each time in urinal flushing. new cloth washing machines and dishwashers are very efficient in water use. drip and sprinkler systems saves40 to 60% of fresh water in farming. 6. development of ‘clean coal technology’ by generation of clean coal seam gas (methane) through underground combustion on coal beds and reaction with hydrogen is a brilliant new idea to utilize the huge coal reserves of world. it is like ‘using coal without mining’. australia is pioneering in the technology. it also utilizes 90% of coal as compared to hazardous conventional mining which only utilize 60%. this has led to significant reduction in the emission of greenhouse gas carbon dioxide (co2) and other toxic pollutants. methane is piped out and supplied to power plants for electricity generation. the ‘flue-gas desulfurization technology’ in conventional coal power plants has also led to significant reduction in sulfur dioxide (so2) emission which causes acid rains. more efficient air pollution control equipment and devices such as ‘electrostatic precipitators’, ‘bag filters’ have also been developed for conventional coal power plants. 7. natural gas, micro-hydel, solar, wind, tidal and geothermal power projects for electricity generation has also come up successfully in world and significantly reduced pollution and greenhouse gas emission. more efficient wind turbines has been developed and they perform very high along the seashore of world. denmark is generating over 90% of its electricity need through seashore wind turbines. the ‘solar photo voltaic cell technology’ has brought a revolution and a new era in economic ‘lighting and heating’ devices and reduction in greenhouse gas (co2). pv system is now used on large scales in domestic, industrial and commercial sectors especially in both urban and rural areas. china is leading in solar power generation. australia is also coming up fast in a revolutionary way supported by govt. 8. development of technologies for recycling of metals, glasses, papers and cardboards, and tough plastics to get back those materials for reuse in society. it avoids mining of ores of metals and the associated environmental hazards, protects trees from cutting to make ‘pulp’ and saves huge amount of freshwater and energy in their production from virgin materials while also reducing emissions of greenhouse gases. production of plastics from ‘synthetic organic chemicals’ is also hazardous process. 9. partial plugging of the ‘ozone hole’ in the stratosphere has been achieved by developing lesser evil substitute hydrochloroflurocarbon (hcfc) which has 30% less odp than cfc, and large part of it is destroyed in the atmosphere before reaching the stratosphere. 10. in the polystyrene foam manufacturing industry ‘carbon dioxide’ is being used as the ‘blowing agent’ replacing cfc. the new technology has eliminated 3.5 million pounds of the dangerous ozone depleting and global warming chemical chlorofluorocarbon (cfc) every year. 11. in the paper pulp industry an environmentally benign oxidant ‘hydrogen peroxide’ is now being used as the bleaching agent replacing the dangerous ‘chlorine’. 12. an environmentally benign non-ionic and sinha et al. 039 biodegradable surfactants called ‘alkyl glycoside’ made from saccharide has been developed to replace the nonbiodegradable anionic ‘alkylaryl sulphonate’ used in shampoos. 13. ‘sodium silicate’ is now used as an environmentally benign alternative to the phosphorus-containing additives in washing powder. 14. hybridization technology and ‘agri-biotechnology’ (abt) has produced high yielding varieties (hyvs) of crops (miracle maize, miracle rice and miracle wheat) which tripled and even quadrupled food production on the same available land area thus increasing agricultural sustainability. 15. a new environmentally friendly technology called ‘catalytic dehydrogenation of diethanolamine’ has been developed in herbicide producing industries that avoids the use of toxic chemicals cyanide and formaldehyde. 16. biological control of pests and diseases in agriculture has become more effective after scientific improvement of the herbal pesticides like ‘azadirachtin’ and ‘pyrethrin’, and development of ‘transgenic crops’. use of earthworms vermicompost also repels and suppresses ‘pests’ and ‘diseases’ by over 80% in crops due to the presence of ‘chitin’ and cellulose degraders microbes. the fermented solution of vermi-compost called ‘vermicompost tea’ and the liquid filtered through the body of earthworms called ‘vermiwash’ is an effective biopesticides. 17. development of biodegradable ‘agro-plastic’. it carries great significance for the environment and society. it is the cheapest and most convenient material ever known to mankind. 18. the ‘membrane filtration technology’ by ‘reverse osmosis’ is most significant new development of water and wastewater treatment without the use of chemicals. it can produce ‘high-quality disinfected water’. it can remove several chemicals (vocs, mtbe, ndma, several endocrine disrupters) and endospores and cysts of pathogenic bacteria and protozoa not removed by conventional methods. 19. the ‘dematerialization technology’ is a significant new development. it leads to reduction in the use of materials (in weight) and energy (in mw) over in all industrial goods and products while fulfilling the same services. it has reduced the use of environmental resources (metals and glasses) and synthetic plastics by more than 20 to 25% in the manufacture of containers, cans and bottles and consequently the energy used and greenhouse gas emitted in their manufacture, and also the quantity of wastes generated after their use and discard. steel beverage cans have been downsized by 40% since 1970. it saves materials and reduce mining activities which has severe impact on environment. 20. development of eco-efficient non-mineral materials which can replace natural resources of earth in development and reduce mining. ceramics, carbon and glass fibres and alloys of aluminium and lithium are new materials with superior technical properties; ultra strong and light weight. automobile and aircraft industries are using carbon fibres instead of steel to reduce weight and improve fuel efficiency. use of steel is reduced by 25%. 21. eco-designing of products to reduce material use and improve efficiency. ferrocement technology’ was developed in india. it use much less cement and steel, has higher degree of toughness, durability, ductibility, tensile strength and crack resistance in less than 25 mm of thickness, which is found in 100 mm thick wall of conventional rcc technology. 22. development of sustainable environmental biotechnologies for municipal and industrial waste treatment, waste reduction, reuse and recycling (converting waste into resource), diverting huge volumes of solid wastes from going to the landfills every year and saving land, cost of transport and landfill construction, and emission of greenhouse gas methane (ch4) from landfills. the most significant development is the global revival of ‘vermiculture biotechnology’ with scientific use of some versatile waste eater and chemically tolerant earthworms species like eisenia fetida, perionyx excavatus and eudrillus euginae whom the great visionary scientist sir charles darwin called as ‘unheralded soldiers of mankind and friends of farmers’. they are ‘protective’, ‘productive’, ‘disinfecting’, ‘detoxifying’ and ‘neutralizing’ (sinha and greenway, 2004). the sustainable vermiculture biotechnology globally six (6) environmental biotechnologies have been identified for sustainable development by scientific use of earthworms: (1) the vermi-composting technology for efficient management of most municipal and industrial organic wastes including sewage sludge by biodegradation and stabilization and converting them into vermicompost (nutritive organic fertilizer). earthworm participation enhances natural biodegradation and decomposition of organic waste from 60 to 80% given the optimum conditions of temperature (20 to 30°c) and moisture (60 to 70%). it takes nearly half the time to convert waste into compost and the process becomes faster with time as the army of degrader worms grows. (2) the vermi-filtration technology for treatment of municipal and industrial wastewater, purification, detoxification and disinfection for their reuse. earthworms body work as a ‘bio-filter’. they can remove the bod5 by over 90%, cod by 80 to 90%, tds by 90 to 92%, the tss by 90 to 95% and the total coliforms by over 99% from wastewater. there is no sludge formation which plagues all the conventional treatment plants. worms also remove the dangerous ‘endocrine disrupting chemicals’ from sewage which cannot be done in the 040 afr. j. environ. econ. manage. conventional systems. all the end-products (detoxified and disinfected nutritive water, vermicomposted sludge and huge earthworm biomass) are useful in agriculture. (3) the vermi-remediation technology for land remediation by removing chemical contaminants from soils and reducing soil salinity while also improving the total physical, chemical and biological properties of soil and its nutritive value. earthworms have been found to bio-accumulate heavy metals, pesticides and lipophilic organic micro-pollutants like the polycyclic aromatic hydrocarbons (pah) from the soil. significantly, vermiremediation leads to total improvement in the quality of soil and land where the worms inhabit and make them highly productive. they swallow large amount of soil every day, grind them in their gizzard and digest them in their intestine with aid of enzymes. only 5 to 10% of the digested and ingested material is absorbed into the body and the rest is excreted out in soil in the form of fine mucus coated granular aggregates called ‘vermicastings’ which are rich in nkp (nitrates, phosphates and potash), micronutrients and beneficial soil microbes including the ‘nitrogen fixers’, ‘phosphate solubilizers’ and ‘mycorrhizal fungus’. hence the polluted land is not only ‘cleaned-up’ but also ‘improved in quality and fertility’. the soil becomes lighter and porous biochemically active and the productivity is increased to several times. during the vermi-remediation process of soil, the population of earthworms increases significantly benefiting the soil in several ways. a ‘wasteland’ is transformed into ‘wonderland’. (4) the vermi-agro-production technology for restoring and improving soil fertility and significantly boosting crop productivity. vermicompost is a highly nutritive ‘miracle growth promoter’. growths and yield of crop plants are enhanced by 30 to 40% higher over chemical fertilizers by worms and its vermicast. studies at csiro australia found that the earthworms and vermicompost can increase growth of wheat crops by 39%, grain yield by 35%, lift protein value of the grain by 12% and fight crop diseases. vermicompost also increases ‘biological resistance’ in plants and protect them against pest and diseases either by repelling or by suppressing them. organically grown fruits and vegetables on vermicompost have also been found to be highly nutritious, rich in ‘antioxidants’ and can be highly beneficial for human health even for protecting against ‘cancers’ and ‘cardiovascular’ diseases. (5) ‘the vermi-health protection technology’ by the use of ‘bioactive compounds’ from earthworms to develop ‘potential modern medicines’ to combat some chronic and deadly diseases like ‘cancers’, cure ‘heart diseases’ and protect human health. the earthworm’s ‘anti-oxidant’, ‘anti-microbial’, ‘anti-cancerous’, ‘immune-boosting’ and ‘clot dissolving’ medicine chest is so powerful as that of any plant and even many pharmaceuticals. (6) ‘the vermi industrial production technology’ for use of earthworms to produce some valuable industrial raw materials. all species earthworms are potential source of ‘biological raw materials’ for production of useful ‘biodegradable’ industrial products in rubber, lubricant, soaps, detergent and cosmetics industries and also as valuable source of ‘proteins’ for production of ‘nutritive feeds’ for promoting allied ‘food industries’ like fishery, dairy, poultry and piggery for meat and milk production. we have successfully experimented on vermicomposting, vermi-filtration, vermi-remediation and vermiagro-production technologies at griffith university, australia with excellent results. they are proving to be most cost-effective and cheap environmental biotechnologies for ‘environmental management and sustainable development’. huge earthworm biomass which is finding new uses in industries and agriculture comes as byproduct in all above technologies. they all have significant contribution towards ‘sustainable agriculture’. vermifiltration of wastewater was our innovative studies done in 2005 and the technology has now been commercialized in india by transchem agritech in gujarat. they are treating 400 kl of sewage everyday and the treated water is being supplied to farmers for use in agriculture saving huge amount of potable water. nearly 80% water is used in global agriculture. several vermifiltration plants are also operating in chile, mexico and venezuela for treatment of municipal and industrial wastewater (this was based on the works done by prof. toha and dr. soto of university of chile).(masoto@cec.uchile.cl). . telecommunication and information technology contributes to sustainability telecommuting is a new concept of working from home using pcs and electronic links. it reduces the need to drive to work preventing emissions and congestion in cities, the need to heat or cool and light big offices which again saves energy and cuts emissions. more than half of the managers of at & t telecom company in the u.s. telecommute one day a week, reducing 80,000 tons of carbon dioxide annually due to reduced travel and transport (unep report, 2002). several official works/business including banking and money transfers can now be done over telephone or through the internet saving travel distance, time and resources. similarly live ‘videoconferencing’ instead of face-to-face talk in official meetings is another emerging environmentally friendly idea. it reduces the need of transport, often long travel distances and times (even visit to overseas) and significantly cuts pollution and carbon emissions while saving resources. however, the boom is communication and information technology has also brought in large amount of electronic products whose generation (version) is fast changing, resulting into their rapid use and discard as electronic wastes. sinha et al. 041 development of more green technologies for sustainable development environmental technologies have to find solutions for both ‘preventive’ as well as ‘curative’ actions for the environmental degradation. it has to protect the vital life support systems of the planet earth – the air, water, soil and the ecosystems, and also manage all the wastes generated by the civilization. it must promise to deliver clean air, safe food, safe water, clean energy, sustainable dwelling and a sustainable transport system for the civilization. more appropriate and sustainable green technologies need to be developed in future for environmental protection and conservation, restoration and repair in the following priority areas of human development to achieve complete sustainability for the human society: 1. commercialization of clean hydrogen fuel for automobiles, and solar, wind, geothermal and oceanic energy for utility power generation. 2. making the conventional energy (fossil fuels and hydropower) sources more clean and green and thus more sustainable. 3. more efficient energy use and conservation in homes, institutions and industries. 4. cost-effective technology for water and wastewater (both municipal and industrial) treatment. 5. more efficient water use and conservation in homes, industries and agriculture. 6. cleaner production in all mining, manufacturing and consumer industries to reduce and even prevent the use of toxic chemicals in production process and eliminate their emissions in wastes. 7. more recycling technologies for all municipal and industrial wastes, for their safe disposal and conversion into valuable resources. 8. methods for ‘safe disposal’ of existing nonbiodegradable plastic wastes, and development and commercialization of ‘biodegradable plastics’. 9. more dematerialization technology to increase the efficiency of natural resource (metals and glasses) use and plastic use and reduce their waste. 10. environmental biotechnology and bioremediation technologies. they are emerging as most cost-effective technologies for environmental managementsolid waste and wastewater treatment, conversion of organic wastes into resource (biofertilizers and biopolymers), stabilization of mined wasteland, decontamination of chemically contaminated sites, safe disposal of hazardous wastes, and soil conservation and erosion prevention etc. the social perspectives for sustainable development the social components of the environmental management and sustainable development is as important as the economic and technological (lovins et al., 1999). technology has provided efficient low-emission vehicles, but what if people continue to drive unjudiciously and unethically; technology has provided energy efficient bulbs, air-conditioners and appliances, but what if people do not buy them as they are more costly or carelessly leave them switched on even during day time and when not needed; technology has provided water efficient taps and showers, but what if people carelessly take longer shower than actually needed, fails to close the tap in-between brushing or shaving, or leave the leaking taps unattended; technology has provided solution to complete waste treatment, waste reduction, reuse and recycling, but what if the industries choose to dump the untreated wastes because treatment or recycling may be more costly than disposal? similarly what if the society does not cooperate in separating the recyclable wastes from the non-recyclables at source? technological process and products that promote sustainability are often costly than the contemporary articles that serve the same purpose and provide the same service. energy efficient fluorescent lights are much more costly than the ordinary filament bulbs; the fuel efficient and reduced emission hybrid cars are more costly than several other models with same facilities. general human nature is to buy cheaper products even if it is harmful to the environment and as long as it meets the social and cultural objectives nicely. hence not only the green technologies have to be cost-effective, their products have to be cheaper too, so that everyone can afford easily and reasonably. guarantee for human rights economic development and environmental protection require social development – efforts to promote and protect internationally guaranteed civil, political, economic, social and cultural human rights. neither economic development nor environmental protection can be fully assured in the absence of respect for fundamental rights and freedoms. certain human rightssuch as access to health and environmental information about the diverse consumer products being used in day to day living (especially about the chemicals used in their production process), information about the environmentally safe quality of land, air and water being used by the society, raising voice against any form of environmental degradation (e.g. tree logging, air, water and noise pollution) in the locality, public participation in governance and redress for any environmental harmmay be very important in achieving sustainable development. sustainability education for the modern technological society environmental education for sustainability is fundamental 042 afr. j. environ. econ. manage. to the success of sustainable development programs (fien, 2001). societal response to environmental issues is often slow as compared to the responses to economic issues such as price rise or health issues such as spread of disease. the society has to be educated to ‘demand’ and also ‘accept’ a particular technology and the technological product which is ‘environmentally friendly’, or ‘reject’ all those products which are ‘environmentally unfriendly’, and then only the industries will be encouraged or even compelled to produce environmentally friendly products. society has to be educated about the judicious and sustainable use of the 5 ps (paper, petrol, potable water, power (electricity) and plastics) in their dailylife. these are the most commonly and most frequently used resources by the society everyday and their production and use has considerable environmental impact. society has also to be made aware about the hidden dangers of environmentally unfriendly products and the adverse impact of their use on human health. they must know their ‘environmental rights and responsibilities’, what is good or bad about environment, which sustain their life on earth. educating for environmental responsibilities of society: sustainable consumption by rich society can lead to universal sustainable development at the root of the entire environmental problem is the unethical increase in the ‘culture of consumerism’ in the developed nations, while the unethical increase in the ‘number of consumers’ (population) in the developing nations. there is also a growing tendency for increasing consumerism in the handful of elitist societies in the developing nations. the environmental impact of both of this cultures, are exceeding the ‘ecological limits’ and the ‘carrying capacity’ (regeneration of renewable resources and assimilation of all wastes) of the earth ecosystems with severe consequences for the future. global consumption expenditure, private and public, has increased at an unprecedented rate worldwide but more in the rich developed nations, since the 1970s reaching some us $ 24 trillion in 1998 (unep-dtie, 2002). this unprecedented growth in consumption (rather over-consumption) in affluent societies of developed nations (and handful of elitist people in the developing nations) has had positive impact as it promoted the growth of consumer industries, but highly negative impact on the environment as more consumption meant more extraction of environmental resources leading to more deforestation, soil degradation, waste and pollution, biodiversity erosion and social inequality. the adverse impacts were felt more in the developing nations where a vast majority cannot afford and suffers from ‘underconsumption’ and inequality. they provided some of their precious developmental resources (geological and biological for dollar earnings) and were also made the ‘dumping grounds’ of the by-products (often hazardous wastes) of over consumption in developed nations. governments in developing nations nurse serious misgivings that the developed nations having followed the culture of ‘over-consumerism’ for several decades, and now wants to deprive the developing nations from their legitimate right to develop and consume in the name of environmental protection and sustainable development. in 1998, unep’s division of technology, industry and economics (dtie) launched a ‘sustainable consumption program’ and tried to dispel the misgivings about reducing consumption worldwide. it emphasized “sustainable consumption is not about consuming less but it is about consuming differently, consuming efficiently, consuming judiciously, and having an improved quality of life for all, (not for handful of few) both in the developed and the developing countries. it also means sharing between the rich and the poor” (unepcdg, 2000). awareness for green consumerism in society: a sign of hope for sustainability companies in developed nations are also beginning to take notice of the growing numbers of ‘green consumers’ in society as awareness about environmental health grew worldwide (eklington and hailes, 1989). global consumer opinion seems heavily weighted towards a growing interest in what lies behind today’s product and services that they buy. apart from price and quality, they want to know how, where and who has produced the product. they want to know what chemicals are there in the product, which can have even a suspected impact on health. this increasing awareness about environment and health in human society is a sign of hope for a sustainable future. government and industry must build on that. social equity, reduction of population and eradication of poverty: a necessary condition for sustainability sustainability refers not only to the natural environment but also to the social environment because social and environmental issues are necessarily inter-wined. some societies have benefited most by new technological development and unsustainable use of resources while others have suffered. there is a nexus between ‘poverty and pollution’, between ‘population and poverty’ and between ‘population and pollution’. nearly 930 millions of people (consumers) are being added every year to the earth demanding more of all resources, more forest to produce food and fuel, and more land to live. if this consuming population is affluent it would further aggravate the problem of unsustainability. hence we must have a sustainable level of population sinha et al. 043 that the earth ecosystem can reasonably support. technology used to harness the resources from the biosphere plays a critical role in resource use and sustainable development. more appropriate and efficient a technology, more efficiently the resource will be used, lesser will be the waste and pollution generation and greater will be the sustainability. the goals of sustainable development cannot be achieved unless we have a new world order with equity at all levels; social, economic, political and cultural. till the evils of ‘poverty and hunger’, ‘inequities and ‘deficiencies’ exist in any part of world, there can be no sustainability in development. social and economic equity is a necessary condition for sustainable human development. if the rich get richer and the poor becomes more in number, that development will not be sustainable over time. if development discriminates against the women and children, that development will also not be sustainable. there is mounting evidence that environmental degradation and economic decline (aggravating poverty) feed on each other, and the fate of the poor and the fate of the planet (earth) have become tightly entwined “the poor are both the victims and the agents of environmental damage. they are forced to consume the environmental resources (even from the very fragile ecosystems) in order to survive, and the impoverishment of the environment leads to worsening poverty and unsustainablity”. economic deprivation and environmental degradation have thus come to reinforce each other in a vicious cycle that perpetuates poverty and destitution in many developing countries and thwarts all efforts towards sustainable development (undp, 2003, 2004). good health: a necessary condition for human sustainability there can be no sustainable development without ensuring basic health services for all in the society. the world health organization (who) reports that 25% of all preventable illness are directly caused by environmental factors. modern health hazards, caused by development that lacks environmental safeguards, such as urban air and water pollution, exposure to ago-industrial chemicals and toxic wastes is becoming common. communicable diseases, especially hiv/aids, cholera and other water borne diseases, tuberculosis and malaria, pose serious obstacle on the road to sustainable development. it is estimated that in this modern technological world 3 million people die every year of water borne diseases or from use of unsafe water. more than 1 billion people globally breathe unhealthy air, and 3 million people die each year from air pollution; two thirds of them poor people, mostly women and children. two million people die every year as a result of slow exposure to indoor pollution caused by burning of wood and dung cake. around 90% of malaria cases in the world are attributable to environmental factors; piling waste and poor sanitary conditions (who, 1997). the economic perspectives for sustainable development the classical economics has failed to guide true human development. current gnp (gross national product) of nations is a false indicator of true economic prosperity. it does not distinguish between resource uses that sustain development and those that undermine it. it is like a ‘malfunctioning strand’ of our ‘cultural dna code’ – carrying erroneous information and signaling to the bodypolitic a form of economic growth analogous to that of cancers cells that consume the host body. all basic biological and physical systems of earth (the true capital resources e.g. soil, water and biodiversity) that sustains life are under severe stress and in fact ‘exhausting’, as ecological destruction continues unabated, yet the key economic indicators shows that the world is prospering (ekins, 1992). conventional economists and the ignorant politicians are not bothering to deduct the cost of environmental destruction (e.g. waste and pollution creation and their health impact, loss of forest and species, degradation of land and soil etc.) and the cost of environmental repair and restoration (e.g. afforestation, waste management and pollution control, soil regeneration and wasteland management, waste water recycling etc.) from the gnp or the rate of economic growth. all economic development programs are implemented through political decisions. the developers and decision makers have to understand that all economic development programs involves the systematic transformation of the world of ‘living things’ (the biosphere – or the natural world which is a product of centuries of evolutionary process) into a world of ‘human artifacts’ (the technosphere or the surrogate world). this means all human development process is necessarily ‘anti-evolutionary’, and therefore, ‘anti-nature’ and it amounts to gross interference into the nature to achieve the goals of economic development. it is imperative that we have to change the strategies of development in order to minimize our interference into the nature. the new economic theory is ‘environmental economics’ which advocates for judicious balance between ‘economy and ecology’ and amalgamation of ‘economic development’ programs with ‘ecological conservation’ strategies to usher in the era of sustainable development. the new economic philosophy of development also stresses mankind to switch over from the ‘fossil fuel based economy’ to ‘renewable and clean energy based economy’. economic planners have to understand that every natural resource, commodity, goods and services that we use from the environment has an ‘environmental cost’ (the hidden cost of environmental damage and repair 044 afr. j. environ. econ. manage. while the raw material is procured from the earthly resources) other than its ‘economic cost’ (the cost of processing, manufacturing and trading) and only after adding the two costs, we arrive at the true cost of the product. there may be ‘social cost’ as well in the form of impaired human health and quality of life. environmental damage can occur at both ends of the cycle the ‘production cycle’ as well as at the ‘consumption cycle’. in the production cycle environmental damage is caused by way of deforestation, earth cutting, soil erosion and pollution etc. to obtain the raw materials by mining the earth and process it in the industries, while in the consumption cycle, the damage is caused because of waste generation once the product is consumed and discarded after use. fossil fuels, nuclear fuels, several metals, papers and plastics and even procurement of human food and drinking water from the nature cause environmental damage at both ends of the cycle. we only pay for the economic cost of the water (cost of harnessing and supply) when we use it in our homes. we do not pay for the treatment of the wastewater when we have used it and converted into sewage. we only pay for the cost of food grown in farms and its processing and transport. we never pay for the damage done to the environment due to production and use of chemical fertilizers and pesticides. we pay for the electricity we consume, but not for the environmental damage that occur by operation of coal power or nuclear power plants and by the construction of huge dams for hydro-power. classical economics only accounts for the electricity generation and irrigation potential of any hydro-power project but never takes into account the losses which incur by way of land submergence and destruction of trees, forest and biodiversity by constructing huge dams. they are not bothered to add the value of the life sustaining oxygen produced, carbon dioxide (greenhouse gas) absorbed, and biodiversity protected by the trees and forest, if they were alive? environmental economics would account for all these. in classical economics a tree has a value only when it is dead and become a ‘timber’, while in environmental economics a live tree has more value as it do more services to mankind by providing food, fodder, fuel and the vital oxygen. it is important that the cost of ‘environmental damage’ and the cost of ‘environmental repair’ must be included in the economic calculations for gnp of every nation (tietenberg, 1988). in a pilot study in mexico, the planners tried to measure the cost of environmental damage and resource depletion due to development. when an adjustment was made for the depletion of oil, forests, and groundwater, mexico’s net national product was almost 7% lower. a further adjustment for the costs of avoiding environmental degradation, particularly air and water pollution and soil erosion, brought the national product down to another 7%. in the agriculture and animal husbandry sector adjustment for the cost of soil erosion sharply reduced the net value added (goodland and serafy,1991). the concept of circular economy: recycling and reuse of waste and resources the new economic philosophy is to cut the use of basic (virgin) materials from the environment dramatically, by boosting ‘recycling and re-use’ the waste including water, energy and materials from one facility/industries/organizations becoming an input in another facility. in circular economy, all economic activities pursue low resource exploitation, maximum efficiency in using materials and energy, and low waste generation. china, the largest growing economy in world has adopted the concept of ‘circular economy’. it has set the following targets for 2010 using 2003 as baseline (unep-dtie, 2002): 1. resource productivity per ton of energy, iron and other resources increased by 25%; 2. energy consumption per unit of gdp decreased by 18%; 3. average water use efficiency for agricultural irrigation improved by up to 50%; 4. reuse rate of industrial solid waste (isw) raised above 60%; 5. recycle and reuse rate for major renewable resources increased by 65% 6. final industrial solid waste (isw) disposal limited to about 4,500 million tones. if all nations both developed and the developing, follows the philosophy of ‘circular economy’ with some set targets for 2010 or 2015 it will great leap forward for the global sustainable development. environmental auditing and accounting of developmental activities there has to be eaa and environmental cost-benefit analysis (ecba) of all those developmental activities and their associated technologies which sustains growth and developmentsuch as management of domestic and industrial wastes; tree planting and afforestation activities; soil conservation, remediation and wasteland development. eaa and ecba are needed for those developmental activities and technologies, too, which otherwise undermine growth and sustainable developmentsuch as deforestation for timber mining and agriculture; encroachment of farmlands and old growth forest for urban development; extraction and processing of ores and minerals from the earth crust in mining and metallurgical industries; production and use of fossil fuels and nuclear fuels; construction of huge dams for hydropower generation; and production and use of agro sinha et al. 045 chemicals for agriculture etc., so as to make these developmental activities environmentally more sustainable making the profit making companies more accountable for sustainable development opinion polls made on the eve of johannesburg summit (2002) clearly show that people worldwide want the companies in both private and public sectors to bear the responsibility of environmental degradation and act with greater responsibility towards its repair and restoration. the behavior of big companies and corporate sectors, and the need to make them more responsible and accountable, has captured public attention and interest in all discussions relating to environmental protection and sustainable development. maximizing ‘short-term profit’ even at the cost of environment and society had been the key principle of operation of almost all companies in world whether in the developed or in the developing countries. burning examples are the ‘petrochemical and agrochemical industries’ of world. one has deliberately thwarted the development of ‘hydrogen fuel technology’ and the other has been conspiring against the development of ‘sustainable alternatives’ to the ‘deadly agrochemicals’ for their own vested interest. unep report says 3 republican senators were seen secretly attending a meeting of oil producing nations in saudi arabia. recently the prince of saudi arabia has realized it and has requested u.s. to give them the technology for development of ‘hydrogen fuel’ in the interest of humanity. in the u.s. farmers practicing ‘vermiculture’ in agriculture had to face problems with the usepa. we have also faced problems in india, while educating farmers about use of vermicompost in farming. agents of agrochemical industries operate in every country misleading the farmers about adverse effects of earthworms on farm soil. the recent trend of ‘deregulation and liberalization’ in all countries (even in nations with communist philosophy) have increasingly allowed companies to do much as they like: 1. their activities generate more than half the greenhouse gases emitted by industrial sectors. 2. they dominate in both mining and trade of natural resources and commodities, thus affecting forests, soils, water and marine ecosystems. 3. they control about four fifths of the land cultivated worldwide for export of crops. 4. they dominate global and national industry and transport, and these developmental activities are major sources of waste and pollution, including toxic and hazardous wastes, unsafe consumer products and occupational health hazards. 6. they are major transmitters of environmentally unsound technologies and production systems and hazardous materials like chemical pesticides (in the name of pest and disease control and crop protection) and hazardous wastes (in the name of recyclables) to the developing countries in the south. 7. they deliberately promote ‘unsustainable consumption patterns’ in both north and south nations through electronic and print media. perhaps the biggest error of the rio earth summit (1992) was its decision not to create a mechanism to regulate the economic activities of ‘big companies and corporations’. although, the ngos like greenpeace and the third world network who dominated at the rio summit had identified the primary role of the transnational corporations (tncs) in damaging the environment. the economic record of the last decades show that the cause sustainable development loses when governments give up their task of regulating companies. tncs should also be made liable for economic compensation for the harmful effects of their operation on the environment, safety of workers and ill effects on the health of workers and the residents in the area. in the u.s., louisiana’s lower mississippi river industrial corridor has been dubbed by the environmentalists and the local residents as ‘cancer alley’. it has over 125 companies manufacturing a range of products including fertilizers, paints, plastics and gasoline. these polluting industries were given a ‘tax break’ of u.s. $ 111 million and the louisiana government wiped out $ 3.1 billion off the books in property taxes. it was an economic incentive given to the industries to create more jobs even at the cost of human health and the environment. ecology was sacrificed at the altar of economy. it was an incentive to pollute more. sustainability for all’ was compromised with ‘prosperity for few’ (wb, 2004). the political perspectives for sustainable development all economic development plans and projects are executed and implemented through some political decision at local, regional or federal level and political decisions are often made to meet the societal goals. in democracy ‘eco-vote’ plays critical role in planning for development. sometimes a political decision is taken to fulfill the election promises to a particular section of the society even at the cost of environment. when it comes to setting prioritieswhether society is to be benefited or the environment, or both, obviously societal needs come first. the fact remains that if environment suffer, society can never remain apart and is bound to suffer. political maturity requires a perfect planning for striking a judicious balance between the two. at the rio earth summit, brazil, 1992, the whole world 046 afr. j. environ. econ. manage. was seen to be divided into two eco-political blocks of north and south on the issues of ‘carbon emission’ and over the ‘rights and access to the genetic resources of the tropical forests’. the ‘arrogance and ignorance’ of the politicians of some developed nations refused to meet the obligations of rio convention and which still continues today. the arrogant statement of the then u.s. president george bush in 1992, that“conventions like these are not going to compel the u.s. citizens to give up their current life-style” expose the political immaturity of a head of state in planning for sustainable development. greening of politics is an urgent requirement today and it must be incorporated in the national and international agenda of every nation for appropriate planning and decision making on vital issues of development and environment. wrong political decisions made for rapid resource exploitation and economic development in some asian and african nations e.g. for construction of huge dams for hydro-power, clearing of ‘tropical forest’ for fodder plantation and export earnings, installation of nuclear power plants and dumping of nuclear and toxic wastes has adversely affected the ecology of the country, irreversibly damaged the ecosystems and biodiversity, displaced and uprooted large sections of human societies from their homes as ‘ecological refugees’ for narrow socio-political and socio-economic gains. damages done to the human environment due to the political conflicts and tensions, terrorist activities, wars and battles resulting from international politics unleashed by arrogant political decisions is also of great concern. environmental policy decisions would require imposition of some new ‘environmental taxes’ like pollution tax, waste tax, tree tax and logging tax etc. and reduction in the regular income taxes. it will require to enhance the prices of environmental goods and services (such as water and energy sources) in order to force the society for their judicious use and consumption. economic incentives have to be given to recycling industries and those saving water and energy in industrial operations by way of reduction in taxation and reduced cost of inputs (raw materials, water and electricity). some pragmatic policy decision has to be taken by the government of all nations with regard to water and energy pricing in society and production of consumer goods by the industries. the short-term objectives of reducing the water and power prices may give fillip to high water and energy consumption with severe environmental consequences, waste and pollution. developed nations are paying high environmental cost (by way of greenhouse gas emission) for the cheap auto fuel, which is in fact at the cost of the whole society. ‘polluter-payprinciple’ has to be enforced in the matters of water and energy pricing and in the matters of waste generation. there has to be a ‘waste and pollution tax’ added up with the consumer products, water and the auto fuel at source. even the government of nations may have to take a hard decision over cutting in the production of ‘private cars’ and ‘subsidize’ the cost of public transport instead of the petrol. government should force the industries to produce and manufacture ‘durable’ goods and not ‘disposable ’ones. all planning and policies for development of appropriate environmental technologies for sustainable development have to be economically viable and socially acceptable. it is also the responsibility of the academia to educate the politicians and decision makers about the benefits of sustainable development technologies. they have to be educated about the ‘hidden cost’ of a particular developmental activity and product such as the ‘fossil fuels’ and ‘plastic bags’ which is apparently cheap at its face value, but are proving very costly in terms of human sustainability. the convenient but ‘non-biodegradable’ plastic bags used in the groceries, cause health hazard during manufacture and also recycling. they have to be ‘banned’ all over the world. conclusion it is impossible to separate economic development issues from environmental issues. almost all forms of development for human welfare erode the environmental resources upon which they must be based, and environmental degradation would necessarily undermine economic development. it is a vicious circle. in the end, the solution to the problem is sustainable development, a process of change in which the exploitation of environmental resources, the direction of economic investments, the orientation of technological innovations and institutional changes are made consistent with the present and well as future needs. sustainability in human society with good quality of life for all can be achieved in two ways: 1. by persuading the people to ‘behave ethically’ towards environment, ‘reduce consumption’, and have a ‘simpler life-style’; 2. by embracing the philosophy of ‘sustainable development’ with appropriate technologies that allow people to enjoy the same good quality of life with high standard of living, but at a significantly lower ‘environmental cost’ (schumacher, 1973). given the difficulty of changing people, the second option appears to be more pragmatic. however, technology should never be seen as a ‘silver bullet’ solving all the world’s environmental ills. environmental education for sustainability can definitely change people in course of time and correct human behavior. technology has provided environmentally sound alternatives for sustainable development in many cases but there is a sad lack of necessary ‘political will’ to implement it because there is fear of resistance from the sinha et al. 047 mighty industrial lobby and their political friends who want to continue with the obsolete and destructive technologies for their own political and economic gains. is it not ironic that man stepped on moon in 1969, but has not been able to commercialize the use of solar, wind and hydrogen power as a viable alternative to destructive oil, and manufacture automobiles run on hydrogen fuels? it is perhaps not favorable to the oil rich nations of world and their ‘purchased politicians’ in the decision making bodies of west. the ‘addiction’ to the ‘cheap oil’ stopped the technologically capable western world to go for sustainable alternative. in the words of gerald durrel (1984), ‘at the present rate of progress and unless something is done quickly, disaster stares us in the face. erosion, desertification and pollution have become our lot. it is a weird form of suicide, for we are bleeding our planet to death. we are led by’ sabrerattling politicians’ who are ignorant of biology, beset by sectarian groups noted for their narrowmindness and intolerance, surrounded by powerful commercial interests whose only interest in nature is often to rape it’ (myers, 1994). there is sufficient evidence to indicate that the world is going on the wrong path of development. it is leading to economic, ecological, social and political deterioration and the worst ‘moral degradation’ in the name of development. it has given birth to violent societies, violence against both man and nature. there are more accidents, crime, delinquency, drugs, alcoholism and deadly diseases than ever before. mankind will perish if the protection of the environment does not become an integral part of all technological development, planning and management. we must seek lessons from history. the flourishing civilizations of the past perished not at the hands of any cruel enemy, but due to human’s own activity, clearing of forest, overuse of soil and lack of awareness for development compatible with the environment (meadows et al., 1992). making economic development programs less dependent upon the ‘fossil fuels’ and more dependent on renewable energy sources, less energy and material intensive and more equitable in its social and economic impact on global level is the need of the hour. a ‘sustainable hydrogen fuel economy’ in place of ‘fossil fuel economy’ must be established if an environmentally and economically sustainable world is to be left to our children and grandchildren. a sustainable future for the human society will be determined: 1. not by the megawatt of energy which will be produced, but by the fact that how they will be produced and from what source? 2. not by the quantity of food that will be produced, but by the quality of the food, and that how they will be produced? 3. by how soon we get rid of those developmental materials and technologies whose production, application and utilization entails heavy environmental damage from beginning to end of the cycle; 4. by how soon we are able to ‘reduce’ and ‘recycle’ all those ‘human wastes’ successfully and develop safe and benign alternatives to those thousands of ‘toxic chemicals’ used in various developmental activities; 5. by how soon we are able to commercialize the ‘hydrogen fuel technology’ for our automobiles and all other renewable sources of energy for power generation; 6. by how soon we switch over completely to ‘organic farming’ to produce ‘chemical-free and health protective organic foods’ for civilization; 7. by how soon we are able to arrest the dangerously growing menace of soil and biodiversity erosion, desertification and land degradation; 8. by how soon we are able to arrest the exploding ‘human population’ (consumers on earth) and the ‘culture of consumerism’ and learn to live a ‘sustainable life-style’ by embracing the philosophy of 5 p’s (judicious use of paper, petrol, power, potable water and plastics) and 5 r’s (refuse, reduce, reuse, recycle and responsibility about waste) in daily life (seymour and girardet, 1987; milbrath, 1989). references adams w (2001). green development; 2 nd edition, routledge pub., london, u.k. axinn gh (1996). philosophy of sustainable development; in rajiv k. sinha (ed.) environmental crisis and human’s at risk; ina shree publications, jaipur, india. pp. 137-142. eklington j, julia h (1989). the green consumer guide – from shampoo to champagne: high street shopping for better environment; victor gollancz ltd. london. ekins p (1992). the gaia atlas of green economics; doubleday / anchor pubublication. fien j (2001): education for sustainability; tela series, australian conservation foundation; centre for innovation and research in environmental education, griffith eco-centre, griffith university, nathan campus, brisbane. goodland d, serafy d (1991). environmentally sustainable economic development: building on brundtland, unesco, geneva. iucn wwf, unep (1991): caring for the earth: a strategy for sustainable living; earthscan, u.k. lovins a, brown l, flavin c, postal s (1999). picturing a sustainable society; in l. starke (ed.) ‘state of the world (1999)’, world 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(1994). the gaia atlas of planet management; gaia books, ltd., london. p. 272. meadows dh, meadows dl, randers j (1992). beyond the limits: confronting global collapse: envisioning a sustainable future; chelsea green publication; post mills., vt. milbrath lw (1989). envisioning a sustainable society; state university of new york press. sinha rk (1994). development without destruction; environmentalist publishers, jaipur, india. sinha rk, greenway m (2004). green technologies for environmental management and sustainable development: giving better quality of life at lower environmental cost: pointer publishers, india. p. 432. isbn 81-7132-375-8. 048 afr. j. environ. econ. manage. better quality of life at lower environmental cost: pointer publishers, india. p. 432. sinha rk (2006). development, environment, human health and sustainability: vol. i :the price of unsustainable development: (p.324) isbn 81-7132-480-0; vol. ii :the wisdom of sustainable development: (p.342) isbn 81-7132-481-9. pointer publishers, jaipur, india steffen w, sanderson a,tyson pd,jäger j, matson pa, moore iii b, oldfield f, richardson k, schellnhuber hj, turner ii bl, wasson rj, (2004). global change and the earth system: a planet under pressure; igbp global change series; berlin-ny, springer-verlag. seymour j, girardet h (1987). blueprint for green planet; dorling kindersley, london. schumacher ef (1973). small is beautiful. harper and row; uk. schmidheiny s, chase r desimone l (1997): signals of change: business progress towards sustainable development; the world business council for sustainable development (wbcsd); tietenberg t (1988). environment and natural resource economics; glenview, iii; scott, forseman & company. undp (2003). human development report 2003: millennium development goals; united nation development program; oxford university press. undp (2004). human development report 2004; united nation development program; ny. unep-cdg (2000). sustainable consumption and production: creating opportunities in a changing world; report of the 4 th international business forum, berlin, 1999. unep-dtie (2002). sustainable consumption and cleaner production: global status 2002; united nation environment program & division of technology, industry and economics, paris, cedex, france. unep-geo (2004-05): global environment outlook (geo) year book 2004-05; unep publication, nairobi, kenya. wced (1987): our common future; world commission on environment and development; oxford university press. wb (2004). world development indicators; world bank report, washington, d.c. who (1997). health and environment in sustainable development; five years after the rio earth summit; world health organization publication, geneva. p. 242. in ternationa l scholars journa ls african journal of environmental economics and management vol. 1 (4), pp. 097-105, november, 2013. available online at www.internationalscholarsjournals.org © international scholars journals author(s) retain the copyright of this article. full length research paper synergies among different parts of sustainable development art kovacic institute for economic research, kardeljeva pl. 17, 1109 ljubljana – slovenia. e-mail: kovacica@ier.si. tel: 386 1 5303 868. fax: 386 1 5303 874. accepted 19 april, 2013 sustainable development became an important paradigm in new eu countries. in new member countries can be seen the development of tools for measuring sustainable development. sustainable development can be measured on many ways. in the paper we will show the evaluation of main determinants of sustainable development. normally more developed countries have a higher sustainability readiness. in the paper the next hypothesis will be tested: first hypothesis: we need a wider set of sustainable development indicators, if we want to measure synergies among different parts of sustainable development. second hypothesis: land used policies have an important influence on sustainable development. third hypothesis: by analysing the indexes of sustainable development we can find the main development steps for improving our position. in the paper it will be shown why we must analyse different parts of sustainable development. sustainable development is usually measured by the system of indicators. we must take into account also the paradigm of the knowledge based economy. the creation of a knowledge-based economy and society, and the preparation of respective action plans presuppose that the situation of the developed economies be analysed and give deeper insights into the current basis of economic development gained. only this basis can serve the planning of future in a way that would guarantee rapid economic development and the harmonisation of the average wage level with that of the european union. this entails both economic and social objectives, according to which europe seeks to become the most competitive and dynamic knowledgebased economy in the world, capable of sustainable economic growth with more and better jobs, and a better social cohesion. key words: economic development, benchmarking, development strategy, environmental economics. introduction sustainable development means integrating the economic, social and environmental objectives of the society, in order to maximize the people’s well-being in the present without compromising the ability of future generations to meet their needs. the management evaluation of sustainability determinants will have an important new value compared to the existing studies about sustainable development on the european level. some companies are not taking the sustainability concept in their programmes and policies. many businesses are realizing benefits from corporate social responsibility initiatives with quantified improvements in revenue and market access, productivity, and risk-management. while emerging-market companies tend to focus more on the short-term cost savings and revenue gains, intangibles, such as brand value and reputation issues, are more significant for the companies that try to increase the sustainable readiness. companies create external effects through their operations or actions. these effects can be positive for example spill over effects from research and income multiplier effects in local communities or negative, a classical example being pollution. it is expected that governments or other entities that are external to the market relevant costs if the impact of the externalities is not acceptable to important stakeholders, for example the investment and the operational costs of pollution, control equipment (steger, 2004). on the business level, we can see the balance between investors, suppliers, consumers, local community, and competitors. being socially responsible is not only fulfilling legal expectations, but also going beyond compliance and investing more into human capital, the environment, and the relations with stake-holders. the experience with kovacic 097 investment in environmentally responsible technologies and business practice suggests that going beyond legal compliance can contribute to a company's competitiveness. going beyond basic legal obligations in the social area, for example, training, working conditions, or management-employee relations, can also have a direct impact on productivity. it opens a way of managing change and of reconciling social development with improved competitiveness. the effects of corporate sustainability management are of great interest to both companies and society. in particular, its micro level economic effects are often the subject of debates and studies discussing the importance and robustness of a business case for corporate sustainability. in the paper the next hypothesis will be tested: first hypothesis: we need a wider set of sustainable development indicators and indexes, if we want to measure synergies among different parts of sustainable development. second hypothesis: land used policies have an important influence on sustainable development. third hypothesis: by analysing main determinants of sustainable development we can find the main development steps for improving our position. the business sustainability is an important challenge of sustainability research. through their operations and actions, companies create external effects, which can be positive (e.g. spill over effects from research and income multiplier effects in local communities) or negative, a classical example of which being pollution. it is expected that governments or other entities that are external to the market relevant costs if the impact of the externalities is not acceptable to important stake-holders, for example the investment and operational costs of pollution control equipment (steger, 2004). it can be seen that the most competitive countries in the eu also have a good position in sustainable development. we cannot achieve a high sustainable position without favourable conditions for the business sector. the correlation between competitiveness and sustainable development is strong. the scandinavian countries rank high by the imd and wef's competitiveness index and by the esi sustainability index. observing the oecd countries only, it is obvious that the high performance of environmental quality, gdp per capita, and competitiveness, as defined by the wef are connected. porter and esty state that, ―the countries that have had the most aggressive environmental policies also seem to be the most competitive and economically successful‖. needless to say, the economists starting from general equilibrium models do not agree with porter’s hypothesis. in a general equilibrium model, there is no such thing as a free lunch, and jaffe et al. (1995) conclude, ―just as we have found little consistent empirical evidence for the conventional hypothesis regarding environmental regulation and competitiveness, there is also little or no evidence supporting the revisionist hypothesis that environmental regulation stimulates innovation and improved international competitiveness.‖ we believe that a more so phisticated use of the environmental indicators and statistical tools to develop systematic and objective ways to gauge results offers a constructive way out of the current stasis. this essay is built on our previous effort to statistically investigate the underpinnings of environmental performance, and on using the findings to rank countries in terms of environmental outcomes and policies. in particular, we seek to explain differences in national environmental results—as measured by the levels of air pollution (particulates and so2 and energy use—based on nationnal policy choices in environmental regulation as well as in broader economic, political, and legal structures). we also empirically explore the question of whether strong environmental performance must come at the expense of competitiveness and economic development, as traditional economic theory has suggested (jaffe et al., 1995). more broadly, we aim to put the environmental decisionmaking on a firmer analytic grounding, and to encourage further efforts to generate better data and improve statistical methods. although hampered by imperfect data, a lack of time series data that would permit more definitive tests of causality, and the need to use relatively crude methods, we find substantial evidence that environmental performance varies systematically with both the quality of a country's environmental regulatory regime and its broader economic and legal context. we use our model to create a framework for measuring the quality of national environmental regulation, and to rank countries on both the quality of regulation and environmental performance. we find a significant correlation between income and environmental performance, suggesting that alleviating poverty should be seen as a priority for environmental policymakers. however, dramatic differences in environmental performance occur even between the countries with similar economic levels. this finding implies that environmental improvement is not merely a function of economic development, but benefits from carefully constructed policy choices. our analysis also suggests that a country's broader economic, legal, and other institutional underpinnings are also important determinants of environmental performance. on the trade-off between being green and being competitive, we have found no evidence that improving environmental quality compromises economic strength. in fact, higher levels of environmental performance appear to be correlated positively with competitiveness. sustainable development stands for meeting the needs of present generations without jeopardizing the ability of futures generations to meet their own needs – in other words, a better quality of life for everyone, now and for generations to come. it offers a vision of progress that integrates immediate and longer-term objectives, local and global action, and regards social, economic and environmental issues as inseparable and interdependent components of human progress. sustainable development will not be brought about by policies only: it must be taken up by society at large as a principle guiding the many choices each citizen makes every day, as well as the big political and economic decisions that have. this requires profound changes in thinking, in economic and social structures and in consumption and production patterns. the european council of june 2006 adopted an ambitious and comprehensive renewed sds for an enlarged eu. it builds on the gothenburg strategy of 2001 and is the result of an extensive review process that started in 2004. the renewed eu sds sets out a single, coherent strategy on how the eu will more effectively live up to its long-standing commitment to meet the challenges of sustainable development. it recognises the need to gradually change our current unsustainable consum-ption and production patterns and move towards a better integrated approach to policy-making. it reaffirms the need for global solidarity and recognises the importance of strengthening our work with partners outside the eu, including those rapidly developing countries which will have a significant impact on global sustainable development. land used policies land used policies (housing, agriculture, forests and urbanization) are becoming more important by implementation of sustainable development concept. before implementation of sustainable development the land used policies were created on their own. now they have to put into account the social and also the environmental development. they are created from the long term perspective. european integration process has fostered the privatization process of stated owned companies. privatization process of stated owned companies has changed the land responsibility in new member countries. development process is different in urban areas than in rural areas. without efficient use of land we cannot reach the sustainable development. one goal of sustainable development is to balance the competing demands for the finite quantity of land available. we have to minimize the loss of rural land to development and to maintain the vitality and viability of towns’ centres with people living close to work place. the sustainable development assessment could be the basis for land used policies. land used policies are taking the sustainable development concept hardly into account. as a source of sustenance, resources and wealth, land is the basis upon which all human societies are built (caldwell and shrader -frechette, 1993). most of the profound changes in the physical and social conditions of human existence have had important land-use dimensions, including, over a long time span, the shift to sedentary agriculture, large scale urbanization (strongly associated with the rise of formal, public, land-use planning) and the globalising influence of information technology. land has been the subject of persistent political struggle, and we might expect the governance of land use change to present a challenging set of issues for the practice of sustainable development. land 098 afr. j. environ. econ. manage. used policies are becoming an important part of sustainable development in recent years. development must take into account the qualitative view of improvement. it is a process of human improvement. it deals with the quality of life. quality of life is becoming the important ob-jective of each country. assessing the development posi-tion of countries takes more in the view the quality of life, because the people needs are the motor of development process. there are many possibilities to measure quality of life, especially in the last years. so, it is not just the environment-economy relationship, but also the social development. sustainable development means integrating the economic, social and environmental objectives of society, in order to maximize human well being in the present without compromising the ability of future generations to meet their needs. our sensibility is that we need a more encompassing definition of sustainable development. it would include programs and policies that promote a more equitable distribution of new jobs and income while boosting a national capacity to innovate. it would foster economic stability and increase the economic and political empowerment of the citizenry. it includes more equal roles for women and minorities, improved health and raised levels of educational attainment, access to better housing, a more effective public transport system, safer workplaces, greater energy and minerals efficiency, and decreased toxics usage among producers (pyle and forrant, 2002). if we observe the national competitiveness from a wide perspective, the most important weights have management and government, because they have an influence on other determinants. with a higher weight of sustainable development the theory concept of national competitiveness is observed from the long term view. we can explain this by analysing competitiveness by main groups as domestic economy, internationalization, government, financial markets, infrastructure, management, science and technology, human capital and environment conservation. all groups have the same weight. from a long term perspective, qualities of government and management have a stronger weight, because they influence on other determinants. policies and strategies on governmental and enterprise level are becoming more important. in the independence research among determinants of sustainable development we have created and own system of indicators. in the research we found the biggest development gaps of slovenia to eu average. in the slovenian, system of indicators has an important share. land presents problems for the more sanguine, ecomodernist interpretations of sustainability, which see salvation in improving eco-efficiency, or »doing more with less«. while it is demonstrably possible to reduce the energy or materials intensity of the economy, relationships between economic activity, land and environmental change make analogous assertions about land-use intensity much more problematic (owens and cowell, 1994). one aspect of the growing interest in land use pla kovacic 099 nning as an instrument of sustainable development has been the expanding range of social, ecological and political objectives that planning systems are deemed capable of promoting. seen collectively, these aspirations amount to a potentially overwhelming brief for institutions with something of a mixed record in meeting public and political desires (cullingwirth, 1997) . land-use policies can sometimes provide a reassuring institutional alternative to measures with more immediate effect, such as green taxes; and when they do bite, local authorities, rather than central government, face the political repercussions. in such circumstances, it is convenient that advocates of sustainable development call for greater local autonomy. planning undoubtedly has been, and continues to be, used in such ways, as we show in relation to environmental assessment, transport and other issues. measuring sustainability benchmark selected countries by economic, social, environmental and institutional indicators show us where we have to act in the way of improving competitive position. by acting as if all regions and countries must follow basically the same stages on their route towards perfection, policy makers do, for instance, sometimes try to enhance the economic development of an area by producing an imitation of the local capabilities, not of the laggards, but of what they believe to be the economically most advanced regions or countries, thereby hoping to become attractive themselves to more lucrative and rewarding industries. productivity growth will be further enhanced by the transition of new member states to a knowledgebased economy, which is at the centre of the eu lisbon strategy. also, the european initiative for growth underlines the importance of investments in networks and in research as crucial steps to boost growth, better integrate an enlarged europe and improve productivity and competitiveness. for the new member states, r and d diffusion and technology transfers are as important as r and d investment as a tool for accelerating the transition towards higher value-added activities. sustaining a high level of foreign direct investment is essential in this endeavour, as is an increased responsiveness of the education and training systems to the changing needs of the labour market. reforms of the education and training systems would also help to encourage the move to more innovative and knowledge intensive activities. in our paper we will made an impact assessment of land used policies (housing, agriculture, forests and urbanization) on sustainable development. the evaluation of sustainable development is the basic approach to the assessment of the development path of the particular country. the selected indicators serve the government/society as the framework for long term policy making. environmental, social, institutional and economic developments are strongly linked. they are crucially important for the well being of the current as well as future generations. but environmental and social policies are sometimes formulated without due regard to their economic consequences. the term sustainability evokes the image of an economic system able to evolve without deterioration from its current state into the long term future, being in balance with nature. this balance may be as much psychological as material and energetic (o'connor, 1998). lee (1991) has remarked: sustainable development has become the watchword for international aid agencies, the jargon of development planners, the theme of crowded conferences, the topic of learned papers, and the slogan of developmental and environmental activists. it appears to have gained the broad-based support that earlier development concepts such as ecodevelopment lacked, and is poised to become the developmental paradigm for the 90s. one of the main theories is that we must be first competitive if we want to reach sustainable development. european union has made its view on sustainability. measuring sustainability reduces to the problems of measur-ing quality of life or human welfare and of measuring environmental impact. we can also plan the sustainable position in the future. a planning and control system is essential for the diffusion of the principles of sustainability. the majority of those systems, today, do not seem to have fully embraced the philosophy of sustainable development. for some, it is because they are limited by measurement systems that were developed to gauge economic/financial performance, and are not equipped to measure social and environmental performance like the balanced sco other frameworks, while accepting all three dimensions as equal, continue to favour the economic/financial performance dimension over the environmental and social dimensions. over the last years the modelling approach is very common. but we cannot measure the sustainable development with modelling approach. we can plan some development years in the energy sector. we have to recognize that the relationships between different parts of development process (figure 1). if the countries can go in the step with productivity of main competitors, some results can be seen in incomes level. the modern countries are oriented on the new development paradigm. concept of sustainable development brings the long term view on development determinants. measuring csr (corporate social responsibility) implementation by questionnaires is from the view of future expects very understandable. the combination of statistical and questionnaire indicators give us the best evaluation of sustainable readiness. measuring sustainability reduces to the problems of measuring quality of life or human welfare and of measuring environmental impact. we can also plan the sustainable position in the future. a planning and control system is essential for the diffusion of the principles of sustainability. the wellbeing of a community or nation can be measured in many kovacic 005 100 afr. j. environ. econ. manage. structure of economy internacionalization management science and technology infrastructure human capital environmental government protection environmental policies sustainable readiness figure 1. model of the influence of government and management on long term sustainable development determinants. source: own model. ways. traditional measurements often analyze a single issue by itself, such as the number of new jobs in a particular com-munity. but such an approach is onedimensional, and does not reveal the quality of those jobs or their impact on the local economy. more meaningful than simply new jobs, measuring the number of children living in poverty indicates the relationship of social health to local econo-mic performance. as staher (1995) has pointed out, when we speak of sustainable development, we have to not only consider the material and economic aspects, but the multidimensional and multifaceted conjunct that com-poses the development phenomenon: its political, social, cultural, and physical aspects. the sustainability of the whole can lean only upon the combined sustainability of its parts. these factors and their respective balances rely on qualitative factors, as the degree of social and political polarization, the values of society and the level of system entropy. based on experimentation and lessons from the field, the sd approach has been operationalized in some interactive steps: 1) identification of the risks, assets, entitlements, livelyhood activities, and knowledge bases of communities and individuals through the use participatory research techniques. 2) analysis of macro, micro and sectorial policies which impinge on people's society. 3) assessment and determination of key technology contributions to sd. 4) identification of existing investment (e.g., micro-finance) opportunities. 5) making sure that the lisbon strategy and the national development strategy are implemented. a framework is needed; one which brings together sd's various elements: coping and adaptive strategies, poverty reduction, sustainability and issues of process. the framework which emerges can then be treated as a heuristic tool or template (by the actors involved in implemen kovacic 101 ting the sd approach) for identifying the linkages between the different elements, developing indicators for them, and evaluating outcomes. a possible option for a conceptual framework within which to place sd concept is the building the own system of indicators. such a framework integrates the concepts of sustainable development and sustainable society. it is best conceptualized as a diagram merging two interactive triangles, one representing the cornerstones of sustainable development (economic efficiency, environmental integrity, and human well being) and the other showing those of sustainable livelihoods (local knowledge, science and technology, and policy structures). it is opined that elements and issues that make for sustainable society lie at the critical interface of human-environment interactions. political, cultural, religious, social, economic, biological and geo-physical factors simultaneously interact with and in combination with each other to produce a variety of functions, processes and products, which shape the way a community makes a living in a given ecozone. analysis of these factors allows policy-makers and practitioners to formulate appropriate and context-specific programmes and projects that aim to promote the sustainable development. having made the case that one way for devising an sd programme or creating indicators for sustainable livelyhoods is by outlining vulnerable livelihoods, we need some kind of theory to ground the variability and dynamism of livelihood systems and adaptive strategies. the identification of human well being as the goal of sustainable development requires indicators which point to how well policies in the economic, environmental, social fields are performing in relation to the main goal. the first step of summarising existing information that focuses on well being is to select a core set of indicators addressing key issues of sustainable development. this core set approach has the benefit of using indicators that are common to different countries, that respond to different uses, and that be meaningfully compared across countries. despite the fact that the choice of indicators may be somewhat subjective, this approach does allow key aspect of sustainable development to be considered in a simple way. however, aggregating a variety of indicators from the various dimensions, it becomes difficult to characterise whether overall economic developments are sustainable or not. the criteria of sustainability suggest that unique advantages of location, which have a characteristic of a public good for local firms but are scarce from the perspective of firms located in other systems, can provide a sustained competitive advantage for local firms. such hard work imitate framework conditions may involve any parts of competitiveness and growth framework; productive resources (unique education system), technologies (national innovative system), organizational arrangements (national networks or organising principles), product market structures (unique demand or supply conditions), international business activities (historical network of foreign contracts), institutional framework (unique re gulatory framework and culture) and the government policies (special support and policies) and the land used policies (housing, agriculture, forests and urbanization) . despite many of its failings, conventional poverty lines conti-nue to be the conceptual and operational foundations for current anti-poverty policies. this being said, however, there are a number of alternative measures of poverty that are gaining momentum. these methods look more at the social and human dimensions of poverty as opposed to economic imperatives. at the heart of this process is the recognition that people go in and out of poverty and it is essential to look at the causes of poverty in addition to its measurement. human development is defined by the expansion of capabilities. unlike income, capabilities are ends, and they are not reflected in inputs, but in human outcomes-in the quality of people's lives. human depriva-tion should not be defined in terms of all capabilities, but only essential or "foundational" capabilities. capability po-verty occurs when people are unable to reach a certain level of essential human achievement or functioning (that is, malnourishment, illiteracy, poor health). examples of ba-sic capabilities are leading a life free of avoidable morbid-dity, being informed and educated, well nourished and having access to satisfactory levels of resource and asset bases. being able to function on the basis of these es-sential capabilities is an objective, observable phenol-menon; it is not a matter of subjective perception, nor is it culture specific. measures of capability should be used to complement an income measure of poverty, but should not be aggregated as conventional poverty lines because of the dimensions of deprivation (i.e., different levels of deprivation between different individuals). a potential so-lution is to use the percentage of the population below an expenditure-based poverty line as a point of reference, and compare this to the percentages of the population deprived in other non-income dimensions. for example, the percentage of people who are illiterate could be con-siderably higher than the percentage of those below the poverty line. sustainablity indexes the eu countries have accepted concept of sustainable development in their documents and also in programme directions (strategy of sustainable development). for accession some countries means the eu accession also the implementing the strategy of competitiveness and sustainable development. new members have implemented the all acquis communautaire. the most developed part of eu finances now the development process of the other one. new member countries are forced to implement the higher cultural and ecological standards. eu is mounting pressure on new members in many ways. building new infrastructure and improving the quality of business development are the basic elements for economic growth. market must be integrated with some elements of regulation, which takes into account the human, kovacic 007 102 afr. j. environ. econ. manage. 2 1,5 1 0,5 0 e c o n o m ic a c ti v it y in d e x o f it e n tr e p re n e u rs h ip in d e x o f h e a lt h e d u c a ti o n in d e x o f la b o u r e n v ir o n m e n ta l e n v ir o n m e n ta l e n v ir o n e m n ta l -0,5 in d e x o f in d e x o f in fr a s tr u c tu re in d e x o f a n d t e c h n o lo g y in d e x o f fo rc e in d e x o f p o s it io n in d e x o f d e v e lo p m e n t in d e x o f p o lic ie s -1 -1,5 -2 finland irland netherland portugal greece slovenia figure 2. position of countries by indexes. source: own calculation. cultural and environmental field. eco-social model of economy is the most important element of sustainability. slovenia has implemented not only the european legal system, but also the eco-social model of economy. enlargement of the eu has bought the current priorities and future direction of eu environmental policy sharply into focus. achieving enlargement while ensuring high standards of environmental protection and social development is the ultimate objective and failure is not an option. significant environmental investments are necessary and the new members need to speed up their preparation to implementing the gothenburg strategy "sustainable strategy". future index is calculated by standard method of deviation. it measures the relative difference between the economies' performances; therefore, each country's relative position in the final rankings is more accurately assessed. first, for each criterion, the average value for each population group is being computed. then the standard deviation is calculated using the following formula: s  (x  x) 2 n the std is calculated by subtracting the average value of each population group from the economy’s original value and then dividing the result by the standard deviation. the std value for criteria is calculated as follows: (std value)i  x  x s where: x = original value x = average value of population group n = number of economies s = standard deviation future index is calculated as an average of ten subindexes: (1) index of economic activity, (2) index of infrastructure, (3) index of information society, (4) index of entrepreneurship and technology (5) index of health, (6) index of education, (7) index of labour force, (8) index of environmental condition, (9) index of environmental development and (10) index of environmental policies (figure 2). index of economic activity this is calculated by aggregation of three indicators: gdp per capita, gdp per capita and share of investment in gdp. the higher gdp per capita level shows that economy has better starting point for reaching the sustainability. this also brings the higher level of consumption behaviour. investments in buildings, machines and in equipment are very important for maintaining the wealth. if the managers of companies are optimistic about a future than the share of investments is higher. index of infrastructure this is calculated by aggregation of three indicators: density of railroad network (survey), maintenance and development of infrastructure (survey) and efficiency of infrastructure (survey). sustainable infrastructure is the efficient infrastructure which takes into account the environmental problems. from this point of view we must put more weight on qualitative than on quantitative part of infrastructure development process. index of information technology this is calculated by aggregation of four indicators: number of hosts per 100 inhabitants, user of internet per 100 kovacic 103 inhabitants, users of mobile phones per 100 inhabitants and availability of it experts (survey) . companies that want to have high prosperity in near future needs an internet strategy. information technology allows us to use human knowledge more usefully. by exploitation of information technology possibilities we can increase the value added in companies. availability of it experts in some countries shows the qualitative progress to sustainable community. index of entrepreneurial activity and technology level this is calculated by aggregation of four indicators: number of patents in force per 100.000 inhabitants, management ant the entrepreneurial orientation (survey), availability of venture capital (survey) and expenditure on r and d as percentage in gdp. if we want to reach the sustainable development then we must change the structure of economy. index of health this is calculated by aggregation of four indicators: expenditure for health as percentage of gdp, quality of health infrastructure (survey), number of physician per 100.000 inhabitants and life expectancy at birth. by ageing of population we need a higher level of health system. so the health system can provide the balance between generations. index of educational level this is calculated by aggregation of four indicators: educational system and the needs of the competitive economy (survey), university education and the needs of economy (survey), higher education achievement and public expenditure on education as a percentage in gdp. today is the really challenge to bring the educational system closer to economy. index of labour force this is calculated by aggregation of four indicators: share of employment in service sector, youth and older persons unemployment. the sustainable economy needs a higher share of services. so the labour market must transform to satisfy the needs of modern economy. index of environmental position this is calculated by aggregation of four indicators: the industrial pollution of water, emission of so2, emission of co2, emission of nox and communal waste. the environmental degradation is the threat for future generations. so we must preserve the environment from nega tive damage from economic and human activity. index of environmental development this is calculated by aggregation of three indicators: production of energy from renewed sources, iso 14001 certifications, share of agriculture land under the organic use). by this indicator we can measure the environmental capita that is important for development process. index of environmental policies this is calculated by aggregation of three indicators: share of protected land, collaboration with economy (survey) and transparency of environmental policy (survey). environmental policies must do more for the competitive economy. environmental regulation can increase the competitiveness of business. benchmarking the slovenian sustainable level is done with five countries: finland, ireland, netherland, portugal and greece. these countries have the size that is close to slovenia. it can be thought that slovenia can reach the higher sustainable level than portugal and greece. finland and ireland economies have reached the higher sustainable progress in last ten years. netherland is close to eu average. finland is the most sustainable country under calculations, with higher ranges in the index of information technology, by index of entrepreneurship and technology and by index of environmental development. finland ranks low by index of health, by index of labour force and by index of infrastructure. ireland ranks the highest by index of education and by index of economic activity. the ireland ranks low by index of infrastructure, by index of health and by index of environmental policies. slovenian readiness for the future in comparism by 19 eu states is not satisfactory. slovenia ranks well by in-dex of entrepreneurship and technology, by index of infrastructure and by index of environmental position. from the view of future readiness is slovenian position low by index of economic activity (-0, 94) by index of labour force (-0, 79), by index of information technology (-0,81) by index of health (-0,79) and by index of environmental policies (-0,68) (figure 3). the calculation of indexes has shown that finland is the best prepared for the future (index 0, 97). after finland are denmark (index 0, 57) and sweden (index 0, 54) the finish position on the first place can be explained as a well developed system of information technology, high entrepreneurship and technological level and a high level of environmental capital. on the other side are poland (index -0, 70), slovenia (index -0, 50) and czech r. (index -0,46) states that are not well prepared for the future. slovenia has some problems on the sustainable way that are connected with low level of economic activity, slow development of information society, low functioning of environmental policies and low balancing of the environmental capital with economic and social development 1.2 1 0.8 0.6 0.4 0.2 0 p o la n d s lo v e n ia c z e c h r p o rt u g a l h u n g a ry g re e c e g re a t b ri ta in it a ly s p a in ir la n d f ra n c e g e rm a n y b e lg iu m a u s tr ia n e th e rl a n d d e n m a rk f in la n d -0.2 s w e d e n -0.4 -0.6 -0.8 -1 figure 3. index of future readiness. source: own calculation. conclusions in the next years the system of indicators will improve. questionnaire will be more common tool for sustainability evaluation. questionnaire indicators give a more qualitative view on competitiveness. the modern way of measuring national competitiveness by using questionnaires allows us to evaluate the dynamic evolution of one economy, the qualitative competitiveness and the expectations of the business managers. managers often evaluate the quality of business environment in which they operate. they also try to forecast the economic situation of the country in the near future. the concept of sustainable development is hardly integrated in national development policy. the implementation of the lisbon's strategy will also improve some parts of sustainable development. slovenian system of indicator has shown the most important development steps in the future. from the system of indicators can be seen that our progress is not integrated enough. indicators serve as valuable tools for sustainability benchmark. an indicator is something that helps you understand where you are, which way you are going and how far you are from where you want to be. this is the main reason why we are going to select indicators for five years period. indicators allow you to see where the problem areas are and help show the way to fix those problems. sectors of the economy generate wealth and welfare for households. enterprises, government and other actors, economic activity, and indeed households themselves, can however create pressure on the environment, through consumption of resources and output of pollutants. the quality of the environment in turn can impact on the welfare households and individuals and other actors. the actors respond to changes in the state of the economy and of the environment, through behavioural and policy changes which either directly affect the environment, or alter the pressures on it from the economic sectors. rather than developing a single index of sustainability, for which important measurement difficultties exist, the identification of a confined set of indicatorsfocusing on each of the three pillars of sustainable development and linked through an organising framework appears as a more useful approach. references baker s (2006). sustainable development, routledge london. bartzokas a, demandt i, ruijters y (1997). environmental legislation on pollution controlin the european union, unu/intech maastricht blowers a (2000). ecological and political modernisation: the challenge for planning, town plann. rev. 71(4): 371-391 caldwell l, schrader-frechette k (1993). policy for land: law and ethics, lanham, maryland: rowman&littlefield clarkson mbe (1995). a stakeholder framework for analysing and evaluationg corporate social performance, acad. manag. rev. 20:92117 cullingworth b (1997). british land use planning: a failure to cope and change? urban stud. 34:945-60 daly h, cobb j (1989). for the common good, green print: london ec (2006) european sustainable strategy, ec brussels faucheux s, nicholai i (1998). environmental technological change and governance in sustainable development policy, ecol. econ. 3(27):243-256 fischer k, scot j (1993). journal of environmental economics and management, 2(37):165-182 jenkins r, barton j, bartzokas a, hesselberg j, knutsen hm (2002). environmental regulation in the new economy, edward elgar, cheltenham kova i a slabe-erker r (2004). the independance among indicators of sustainable development, ier ljubljana lee s (1991). sustainable development: a critical review, world development, 6(19):607-621 o'connor m (1997). "environmental valuation from the point of view of sustainability" in dragun, a., jacobbson, k. sustainability and global environmental policy, edward elgar: cheltenham, pp 149-80 oecd (2001). the dac guidelines, strategies for sustainable development, oecd paris oecd (2002). overview of sustainable development indicators used by 104 afr. j. environ. econ. manage. national and international agencies, oecd statistics working paper steger u (2004). the business of sustainability, palgrave macmillan 2002/1, paris new york owens s, cowell r (2002). land and limits, interpreting sustainability xepapadeas a, zeeuw a (1999). environmental policy and in the planning process, routledge london competitiveness: the porter hypothesis and the composition of pyle l, forrant r (2002). globalization, universities and issues of capital, j. environ. econ. manag. 2(37):165-182 sustainable human development, edward elgar cheltenham schmidheiny s (1992). changing course, cambridge, mit press kovacic 105 african journal of environmental economics and management vol. 1 (2), pp. 049-058, september, 2013. available online at www.internationalscholarsjournals.org © international scholars journals full length research paper environmental management in brazil: a survey evaluating current practice and performance in the industrial sector wagner cezar lucato*, rosângela maria vanalle, milton vieira júnior and josé carlos da silva santos industrial engineering post graduation program, universidadenove de julho – são paulo, brazil. accepted 24 april, 2013 the rapid urban development observed in major cities and the resulting environmental impacts have made the lessening of these impacts a key objective in sustainable development and companies have been required to consider economic, environmental and social consequences in their cultures, strategies and decision-making processes. the goal of this paper was to evaluate to what extent manufacturing companies have been responding to these challenges. the study was performed with a survey that considered 63 manufacturing firms of different sizes and from a variety of sectors located in brazil. the results of the research and the statistical analysis performed on these results suggested that the actions taken by industries to face their environmental challenges have generally been effective and surpassed the environmental demands enforced by the law in multiple ways. the hypotheses tested as part of this experiment allowed the researchers to verify that companies with iso 14001 certification had better environmental performance than those without it, as expected. it was also possible to verify that the discipline imposed by forms of certification other than iso 14001 have had positive influence on the environmental performance. the research results confirmed that multinational companies had better environmental performance than brazilian national firms. on the other hand, firm size did matter in terms of environmental performance, but no significant difference was perceived among manufacturing companies in different industrial sectors. key words: environmental performance, industrial pollution, sustainable development, survey, brazil. introduction the environmental impacts of urban expansion have been extensively analysed, illustrating the adverse effects this expansion has had on air, water, and soil (brehemy, 1992; camagni et al., 2002; pare´s-franzi et al., 2006; wu et al., 2010). in fact, environmental degradation has intensified as production and consumption have expanded (jabbour and santos, 2008), which has made the reduction of the environmental impacts resulting from *corresponding author. e-mail: wlucato@uninove.br. tel/ fax: + 55 11 3665-9355. accelerated urban expansion a key objective in sustainable development (pare´s-franzi et al., 2006). as a result, businesses have generally been pushed to incurporate economic, environmental and social performance measures into their cultures, strategies and decisionmaking processes (brent and visser, 2005). environmental issues can usually be expected as a result of urban human concentrations and dense economic activity. for instance, emissions in the são paulo metropolitan area (the most industrialised region in brazil) amounted to 1.6 million tons of carbon monoxide, 382 thousand tons of hydrocarbons, 376 thousand tons of nitrogen oxides, 63 thousand tons of particulate lucato et al. 049 material and 26 thousand tons of sulphur oxides in 2009 (cetesb, 2010). it is true that most of those emissions have arisen from motor vehicle (tavares et al., 2011). however, public authorities have also put pressure on the industrial sector to minimise pollution problems in the area. with these issues in mind, the main purpose of this paper was to analyse to what extent the brazilian industries have been responding to current environmental challenges. this goal was realised through a survey that considered63 national and multinational industries of different sizes and from different sectors, located predominantly in the são paulo state. the results allowed the researchers to understand the current environmentrelated practices actually employed by the industries under study and how these practices have contributed to their current environmental performance. sustainable development can be defined as meeting the needs of current generations without impeding future generations from meeting theirs (smith and rees, 1998). sustainable development cannot be achieved without the effective implementation of environmental management in companies, and it has become critical to their survival in a competitive globalised world (preston, 2001). thus, business sustainability requires the integration of the three pillars of sustainable development (social justice, economic efficiency and environmental performance) into a company's operational practices. firms have been increasingly required by external stakeholders to commit to and report on the respective sustainability performance of their operational initiatives (labuschagne et al., 2005) as a way to enhance to the goal of becoming high performance or “world-class” organisations (molefe et al., 2011). according to srebotnjak (2007), many different definitions of environmental performance exist. however, the iso 14001 standard – environmental management system specification and use – defines environmental performance as “measurable results of an organization’s management of its environmental aspects” (iso, 2004, p.3). iso 14001 is also the international standard that permits organisations to obtain an environmental management system certification. as a specification standard, it is part of the iso 14000 family, a full set of iso environmental procedures. iso 14001 enables firms to pursue continuous environmental improvements using the pdca (plan-do-check-act) model (angell and klassen, 1999) and also illustrates how an environmental policy simplifies environmental planning, implementation and operation by continuously checking company’s environmental performance and taking corrective actions when required. the central assumption of this approach is that by improving its manufacturing processes, a firm can provide better environmental practices, improving its financial and operational performance as a result (gavronski et al., 2013; nawrocka and parker, 2009; silva and medeiros, 2004). according to may et al. (2002), companies should understand their respective environmental performance to formulate proper environmental policies, plans, and programs for their activities. some scholars have developed research on the correlation between environmental and business performance. for instance, results from klassen et al. (1996), king and lenox (2001) and koner and cohen (2001) have indicated that businesses with better environmental performance and less pollution show a higher financial performance. to help organisations measure their environmental performance, the international organisation for standardisation (iso) has developed the iso 14031 standard – environmental management and environmental performance evaluation and guidelines (iso, 1999). according to iso, the environmental performance evaluation is “an internal process and management tool designed to provide management with reliable and verifiable information on an on-going basis to determine whether an organisation’s environmental performance is meeting the criteria set by the management of the organisation”. therefore, environmental performance evaluation is considered a process or a tool dealing with the utilisation of indicators (jasch, 2000; tsoulfas and pappis, 2008). iso 14031 also proposes a methodology to measure the environmental performance of companies in terms of definitions, working structures, and different types of quantitative indicators such as environmental, management and operational performance indicators. note that indicators are the main tools used in this standard, and are defined as the “specific expression that provides information about an organization’s environmental performance” (iso, 1999, p.7). despite an increasing focus on various environmental performance indices at the national, sectorial and company levels (srebotnjak, 2007; mayer, 2008), the environmental performance measurement remains one of the greatest challenges to organisations (johnston et al., 2001) because the uncertainty of measurements in relation to the indicators used is often neglected. on the other hand, the uncertainty of raw data is a critical issue, because an indicator can reveal a true picture of environmental performance only if it is based on goodquality data (perotto et al., 2008). in addition, the basic objective of environmental performance evaluation through the use of indicators is to assure that industrial activities evolve in line with sustainable principles that are acceptable to society and the environment. in practice, environmental performance indicators can be used in several decision situations by internal and external stakeholders to assure a continuous process of environmental impact reduction in products or processes. internal stakeholders require detailed indicators to monitor and control the environmental performance of their products and activities as part of their business processes. conversely, external stakeholders need broader indicators that can enable them to pressure the company for continuous improvement of its environmental performance (thoresen, 1999). the main purpose of this paper was to investigate to what extent the industries located in brazil have been responding to current environmental challenges. to that end, the authors decided to identify the key environmental practices being executed by industries in the area and how those practices could express the environmental performance of each. the following hypotheses (h) were also posed to investigate the relationships between a firm’s environmental performance and some of its key characteristics: h1: companies with iso 14001 certification have better environmental performance than those without it. gavronski et al. (2013) have indicated that iso 14001certified brazilian companies have created a more integrated approach to environmental management by adopting practices that favour their environmental performance. therefore this paper tested the selected research sample by confirming through hypothesis h1 that iso 14001 certification had a positive impact on environmental measurement. h2: the discipline imposed by certifications other than iso 14001 positively influences environmental performance. oliveira and pinheiro (2009) have confirmed the importance of minimising the resistance to change caused by iso 14001 certification in brazilian companies. this paper verified that the adoption of other types of certification (like iso 9001, for instance) could positively impact the implementation of environmental practices that result in better environmental performances. h3: multinational companies have a better environmental performance than brazilian national firms. many managerial practices used by multinational companies are progressively being emulated by the local manufacturing community in developing countries (cruz and pedrozo, 2009; melnyk et al., 2003). therefore this study investigated whether this statement applied to the environmental practices lead to environmental performance. h4: firm size matters to environmental performance. it has been postulated that larger companies have higher environmental awareness than smaller firms (jabbour et al., 2010). this paper verified if the environmental performance of larger companies was significantly better than that observed in medium and small firms. h5: companies belonging to the auto industry have better environmental performance when compared to other industrial segments. there is a conceivable expectation in brazil that environmental performance in the auto industry is far better than that observed in other manufacturing sectors as a result of the stringent requirements imposed by multinational auto assemblers on their entire supply chains (vanalle et al., 2011). to see if this fact could be confirmed, this study tested whether the auto industry’s environmental performance was significantly different from that identified in other manufacturing segments. research methodology a survey was conducted as per forza (2002) to evaluate the environmental practices employed by industries in brazil and the listed research hypotheses. for that purpose a population frame was composed by all the industrial companies associated with the são paulo industrial federation. among them 150 industrial firms were randomly chosen by means of a systematic sampling where one firm was selected for every 10 existing in the population frame. a questionnaire with closed questions was then sent by e-mail to the person in charge of environmental management in industrial firms forming the research sample. the researchers subsequently contacted these persons by phone to encourage completion of the questionnaire. of the questionnaires sent, 63 or 42% were fully and adequately answered and used to support the analysis and findings in this paper. the questionnaire was comprised 11 questions that covered: a) current environmental licence status (1 question); b) solid and liquid waste disposal methods (4 questions); c) environmental consideration in product design, manufacturing processes and purchasing (3 questions); d) potential pollution problems affecting the firm’s neighbourhood (1 question) and e) environment as a key strategic factor (2 questions). each question posed five statements describing different approaches to each of the subjects being considered. those statements described typical practices ranging from those with a high level of environmental awareness and commitment (that is, best practices) to those involving no environmental concern at all (that is, worst practices). however, as a result of the questionnaire testing, the sequence of practices presented to the interviewees changed from question to question to avoid answering bias. as an example, one of the questions posed to the interviewees is shown in figure 1. note that letters (a) to (c) added to this example indicate best environmental practice (a) and worst environmental practice (e).(b), (c) and (d) were used to show the 3 intermediate alternatives. these letters were not included in the questionnaire sent to the firms. the returned questionnaires were analysed to verify the adequacy and consistency of the answers provided by the interviewees. from the 72 questionnaires received, 9 were discarded due to apparent inconsistencies. the remaining 63 were tabulated and their data were processed using spss – statistical package for social science for windows version 13 (spss inc., chicago, il, usa). although the literature provides several alternatives to measuring the environmental performance of a company (verfaillie and bidwell, 2000; oecd, 2002, 2005; huppes and ishikawa, 2005; styles et al., 2009a, 2009b), this study proposes an environmental performance evaluation method based on the best environmental practices actually used by organisations. this approach identified the environmental practices being utilised by a given company in predefined areas and granted a certain number of points to each 050 afr. j. environ. econ. manage. lucato et al. 051 in relation to the sanitary sewer and other liquid wastes not used in the manufacturing floor: (c) ( ) the company disposes them in the public sewage system but the effluents are disposed with no treatment in a body of water; (d) ( ) the company disposes them in the public sewage system but doesn’t know the final destination of its effluents; (a) ( ) the company has its own sewer treatment plant and totally reuses the water resulting from this treatment process; (e) ( ) the company disposes them with no treatment into cesspit, into a nearby body of water or other places. figure 1. one example of a question posed to the interviewees. letters (a) to (e) added to this example to indicate best (a) and worst (e) environmental practices. (b), (c) and (d) represent statements with intermediary environmental concerns. these letters were not included in the questionnaire sent to the firms. practice. a maximum number of points was given to those practices reflecting high environmental commitment and a minimum number of points was granted to those practices reflecting no environmental concerns at all. proportional points were given to different situations in-between those two extremes. by adding all of the points obtained by a particular company, it was possible to calculate a score that could serve as a measure of that company’s environmental performance. hence, to measure a company’s environmental performance, 5 points were granted to each question for which a best practice was selected by the interviewee. on the other hand, 1 point was granted whenever the answer indicated a nonenvironmental practice. 4, 3 or 2 points were granted for the 3 intermediate alternatives depending on the statement chosen. the overall environmental performance of a given company was measured by adding the points obtained from the 11 questions, ranging from a minimum of 11 possible points to a maximum of 55. comparisons of environmental performances of different sets of firms were required to test the 5 hypotheses proposed by this study. those evaluations required, where appropriate, descriptive statistics and hypotheses testing using two samples mean comparisons through an independent t-test and several sample mean comparisons using a one-way anova. significant coefficients were identified at p<.05 as per dancey and reidy (2007). 17 belonged to the automotive sector, 5 to the electrical component manufacturing sector, 25 to the metalmechanical sector and 16 to 12 other industrial sectors; and d) certifications: 25 of the researched companies had both iso 9001 and iso 14001 certifications, 30 were only iso 9001 certified, 2 were only iso 14001 certified and 6 had no iso certifications. the survey results were initially evaluated on a question-by-question basis with the objective to identifying the most common environmental practices used by the companies under study and those practices’ influence on a company’s environmental performance. statistical analyses were then developed to evaluate if variables such as ownership, size, industrial sector or quality and environmental certification could induce differrent environmental performance in the researched companies, a practice called the performance comparison. question-by-question analysis results and discussion as alluded to already, the survey was answered by 63 companies with the following characteristics: a) ownership: 23 were subsidiaries of multinational companies operating in brazil and 40 were national firms; b) size: 15 were small (less than 100 employees), 26 were medium (between 100 and 499 employees), 13 were large (between 500 and 1,999 employees) and 9 were very large (more than 2,000 employees); c) industrial sector: after analysing the returned questionnaires it was possible to group the results as shown in figure 1, where a represents the statement reflecting the best environmental practices and e the worst. b, c and d signify statements with intermediary environmental concerns. the numbers shown in each column indicate the number of companies that reported the use of each environmental practice presented on the left (a, b, c, d or e). for instance, in terms of the first environmental aspect analysed (adequate licensing), 53 of the 63 researched companies indicated that they had all the required environmental permits (statement a), 3 stated that they did not have any environmental licences at all (statement e) and 1 noted that it was still in the process of obtaining the appropriate licences(statement d). the first question posed to the interviewees asked about the current status of their companies’ environmental licences. 59(94%) of the companies indicated that their licences were in full compliance with local legislation, indicating that being legally accountable was a major concern among industries in the research area. of the remaining 4 companies, 1 affirmed that it was in process of fixing licensing issues and only 3 small companies stated that they did not have the necessary documentation. in terms of dangerous solid wastes, 15 firms (24%) indicated that they did not generate any such waste. of the remaining 48, 47(98%) said they provided adequate waste disposal in accordance with local regulations and under direct supervision of environmental authorities. the other company stated that it disposed of dangerous solid wastes according to the legal requirements, but with no previous authorisation from environmental authorities. no other environmental issues were reported in this section of the questionnaire. 19 companies (30%) mentioned that they did not generate any industrial effluents in addition to conventional sewage material. of the other 44, 24(55%) indicated that they performed an adequate treatment prior to returning effluents to the environment because they did not reutilise them in the manufacturing process. 6 firms (14%) performed some reutilisation and the remaining 14 (32%) reutilised all effluents for further use. note that all of the researched companies performed an adequate effluent disposal and only the degree of effluent reutilisation varied. the results on sewage disposal were not as positive. 43 companies (68%) either had their own treatment plant with which to reutilise water (13 firms or 20%) or dispose of sewage effluent into the public system where proper treatment could be performed (30 companies or 48%). 10 (16%) said they disposed sewage effluents into the public system, but the sewage ended up in a nearby river with no treatment at all. the remaining 10(16%) indicated they disposed of sewage materials into a cesspit or directly into a nearby river. as far as non-dangerous solid waste are concerned (manufacturing, general garbage and organic materials), 42 companies (67%) reported that they performed waste separation and send it for recycling. 61(97%) had their scrap and inorganic garbage removed by third parties for adequate disposal in authorised landfills, while organic wastes were removed by the municipal garbage collection services. only two firms stated that they sent both organic and inorganic wastes to an unauthorized location (table 1). in terms of product design, 56 companies (89%) indicated that they accounted for environmental aspects when designing their products. however, only 31(49%) considered the environmental impacts of disposing of a product after its useful lifespan. the remaining 24(38%) assumed that the product’s destination was the final consumer’s responsibility. only 6 firms (10%) did not consider environmental issues when designing their products. on the other hand, manufacturing process design is fared much better. 57 companies (90%) considered raw material and energy conservation along with toxic material elimination, reduction (of both quantity and toxicity) of wastes and gaseous emissions when designning their manufacturing processes. only 6 firms (10%) stated that they considered environmental constraints in their manufacturing process as long as these constraints did not adversely affect their manufacturing costs. purchasing processes were also questioned in the survey. 58 firms (92%) considered environmental aspects to some extent during their purchasing process. of these, 12 companies (19%) indicated they purchase materials and services exclusively from vendors with some type of environmental certification, while other 15(24%) adopted the same approach but only for items with high pollution potential. the remaining 31(49%) stated that they had a preference for environmental certified vendors, provided that the vendors had the same commercial conditions as the non-certified sources. only 5 (8%) firms declared that they did not consider environmental aspects in their purchasing processes. the next question was about the relationship a company had with its community in terms of its pollution potential. 48 firms (76%) reported not having any type of problem. the other 15(24%) indicated that minor complaints from neighbours had been reported, but the situation had been settled with no adverse impact on community relationships. in terms of the environmental practices used by the companies under study, 59 firms(93%) confirmed that these practices were the result of the company’s own initiative, inspired by the understanding that: a) environment protection is one of the pillars of sustainability (41 companies or 65%); b) modern companies should be concerned with protecting the environment (16 or 25%) and c) this is a concept already adopted by most of a company’s competitors (2 or 3%). 3 firms (5%) indicated that environmental practices had been imposed by their clients and only one company stated that it was not concerned with environmental issues. 42 companies (77%) confirmed that environment protection was one of their key strategic elements as perceived by both internal and external stakeholders. 20 (32%) declared that they were concerned with environmental aspects but that these aspects were not part of their strategic thinking. only one company stated that it was not concerned with environmental issues. as stated earlier, a given company’s environmental 052 afr. j. environ. econ. manage. lucato et al. 053 table 1. number of companies indicating environmental practices currently in use (a represents a statement reflecting the best environmental practices and e the worst. b, c and d represent statements with intermediary environmental concerns). a de qu at e en vi ro nm en ta lli ce ns in g a d e q u a te s o li d w a s te d is p o s a l a d e q u a te e ff lu e n t d is p o s a l a d e q u a te s e w a g e d is p o s a l a d eq u at e n o n -i n d u st ri al g ar b ag ed is p o sa l e nv ir on m en ta l c on si de ra tio ns in pr od uc td es ig n en vi ro nm en ta l c on si de ra tio ns in m fg .p ro ce ss de si gn e nv ir on m en ta l c on si de ra tio ns in pu rc ha si ng r el at io ns hi p w ith ne ig hb ou rin gc om m un iti es en vi ro nm en ta l p ro te ct io n as its ow ni ni tia tiv e en vi ro nm en ta l p ro te ct io n as ak ey st ra te gi cd ire ct io n best environmental practice a 59 15 19 13 42 32 53 12 48 41 27 b 0 47 14 30 14 12 4 15 15 16 15 intermediary environmental c 0 1 6 4 2 12 0 11 0 2 0 practice d 1 0 24 6 3 1 6 20 0 3 20 worst environmental practice e 3 0 0 10 2 6 0 5 0 1 1 total 63 63 63 63 63 63 63 63 63 63 63 performance was measured by granting 5 points to each question for which a best practice was cited by the interviewee and 1 point whenever a non-environmental practice was selected. 4, 3 or 2 points were granted as the other 3 possible alternatives depending on the statement selected. a company’s environmental performance was measured by adding the points obtained from the 11 questions. applying those assumptions to the 11 questions answered by each of the 63 companies included in the survey, it was possible to calculate each company’s environmental performance. the following descriptive statistics on the 63 firms’ environmental performance were calculated using spss for windows 13.0 software: a) a performance range with a: minimum of 29 (compared to a possible minimum of 11) and a maximum of 53 (against a possible maximum of 55); b) a sample distribution mean of 45.1; c) a sample distribution median of 46.0; d) a sample distribution standard deviation of 5.04; e) a 95% confidence level interval for the a mean of 43.8 < µ < 46.4. the statistical analysis also indicated that the environmental performance was normally distributed about the mean. the environmental performance of the industrial companies located in the research area showed that the environmental concerns represented a great deal more than conventional corporate speech. environmentallyfriendly practices have been actually used to a great extent by the majority of industrial firms in the area, regardless of their size, ownership or industrial sector they belong. these statistics were not the result of law enforcement, because many of the practices described in the questionnaire were not imposed by environmental laws. some examples of these practices are described as follows a) there is no legal obligation for companies to select and recycle non-industrial garbage, but 42 out of the 63 researched companies (67%) selected and recycled the garbage anyway, b) there is no provision in the law requiring environmental considerations when defining manufacturing processes. however, 53 firms (84%) indicated that they were concerned with the conservation of materials and energy, elimination of toxic wastes and reduction of toxicity and quantity of wastes and emissions when they developed the fabrication processes for their products, c) environmental legislation does not impose rules on a company relationship with the community in the vicinity of its plants. however, 48 firms (76%) expressed deep concern about maintaining the neighbouring public’s immunity to pollution problems caused by their manufacturing operations. therefore, it seems that increased environmental awareness could be considered a possible source for several of the environmental initiatives taken by local industries. performance comparisons h1: the data collected in the survey enable some interesting comparisons. initially, it would be reasonable to expect that companies with iso 14001 certification would display better environmental performance than table 2. spss output for the independent t-test on the equality of the means in h1. levene´s test for t test for equality of means equality of variances f sig. t df sig. (2-tailed) mean std. error 95% confidence difference difference interval performance equal variances assumed 9.61 .003 -2.472 61 .016 -3.0463 1.23224 -5.5103 -0.5822 equal variances not assumed -2.688 55.03 .009 -3.0463 1.13311 -5.3170 -0.7755 those without it (fortunski, 2007). this statement was tested as a research hypothesis to verify if it could be accepted with a significant level of confidence. in fact, calculating the environmental performance of the iso-certified companies they yielded a 46.9 mean and a 3.0 standard deviation. the mean and standard deviation of the other firms were 43.8 and 5.8 respectively. to verify if there was an actual significant difference between the two means, an independent t-test was conducted to compare the environmental performance means of the 27 iso 14001 certified companies and the other 36 firms. using spss for windows 13.0 it was possible to obtain the results shown in table 2. table 2 shows that the independent t-test for 61 degrees of freedom demonstrated that if the null hypo-thesis was true the result would be improbable because t(61) = 2.47; p < .016. in conclusion, the research hypothesis was accepted because there was actually a difference between the environmental performance of the iso 14001certified companies and the non-certified firms, as initially expected. h2: does the discipline imposed by certifications other than iso 14001 influence environmental performance? to test this hypothesis the companies with no environmental certification were grouped together, and a comparison between the environmental performances of the 30 iso 900certified and the other 6 non-certified firms was performed within this set. the following results were obtained: a) the environmental performance mean of the iso 9001-certified companies was 44.8, with a 4.2 standard deviation; b) the other firms had a 38.7 mean and a 9.8 standard deviation. to verify if a significant difference between the two means existed, an independent t-test was also conducted as shown in table 3. the independent t-test for 34 degrees of freedom could demonstrated that if the null hypothesis was true, the results would be improbable because t(34) = 2.54; p < .016. in conclusion, the research hypothesis was accepted. in the absence of iso 14001 certification, there was a difference in the environmental performance of the iso 9001-certified companies and the other firms. h3: another research hypothesis was related to ownership: do multinational companies have better environmental performance than brazilian national firms? the results of testing this hypothesis are as follows: a) the environmental performance mean of the 23 multinational companies was 47.6, with a 2.6 standard deviation, b) the 40 national firms had a 43.7 mean and a 5.5 standard deviation. the significant difference between the two means was also verified through an independent t-test as shown in table 4. the independent t-test for 61 degrees of freedom demonstrated that if the null hypothesis was true, the results would be very improbable because t(61) = 3.27; p < .002. in conclusion, the research hypothesis was accepted because there was a statistically significant difference in the environmental performances of the multinational and national companies. h4: does size matter when considering environmental performance? to test this hypothesis, the companies under study were divided into four groups: 9 very large, 13 large, 26 medium and 15 small. the descriptive statistics for those groups were: a) very large mean 47.4 and standard deviation 4.0; b) large mean 47.1 and standard deviation 2.6; c) medium mean 45.6 and standard deviation 4.6; and d) small mean 41.1 and standard deviation 5.2. to verify if a significant difference existed among those means, a one-way anova test was performed using spss for windows 13.0. the results are shown in table 5. the f test for 3 (between the groups) and 59 (within the groups) degrees of freedom verified that if the null hypothesis was true, the result would be very improbable because f(3;59) = 5.49; p < .002. in conclusion, the research hypothesis was accepted because there was a statistically 054 afr. j. environ. econ. manage. lucato et al. 055 table 3. spss output for the independent t-test on the equality of the means in h2. levene´s test for t test for equality of means equality of variances f sig. t df sig. (2mean std. error 95% confidence tailed) difference difference interval performance equal variances assumed 12.338 .001 -2.54 34 .016 6.16667 2.42717 1.23405 11.0993 equal variances not assumed 1.518 5.384 .185 6.16667 4.06369 -4.0589 16.39230 table 4. spss output for the independent t-test on the equality of the means in h3. levene´s test for equality of t test for equality of means variances f sig. t df sig. (2mean std. error 95% confidence tailed) difference difference interval performance equal variances assumed 9.375 .003 3.265 61 .002 4,00217 1.22572 1.55120 6.45315 equal variances not assumed 3.893 59.284 .000 4.00217 1.02817 1.94501 6.05934 significant difference in environmental perfor-mance depending on the size of the company under consideration. however, post hoc analysis considering multiple comparisons as per tuckey’s hsd (honestly significant differences) test, indicated that significant differences existed at the .05 level only between the small companies and all the other firms. no differences were significant between the very large, large and medium size firms. h5: this research also investigated a widespread idea in the literature indicating that companies belonging to the auto industry have had better environmental performance compared to other industrial segments due to the stringent environmental requirements imposed by auto assemblers on their entire supply chains. to test this hypothesis the firms under study were divided into four segments: 17 belonging to the automotive sector, 5 to the electrical component manufacturing sector, 25 to the metal-mechanical sector and 16 to 12 other industrial sectors. the descriptive statistics for those groups were: a) automotive – mean 44.2 and standard deviation 5.9; b) electrical component manufacturing – mean 46.4 and standard deviation 3.16; c) metalmechanical – mean 44.7 and standard deviation 4.4; and d) all others – mean 46.4 and standard deviation 5.2. to test if a significant difference existed among those means, a one-way anova test was once again conducted, which produced the results shown in table 6. the f-test for 3 (between the groups) and 59 (within the groups) degrees of freedom demonstrated that the null hypothesis could not be rejected because f(3;59) = .69; p < .561. in conclusion, the research hypothesis was rejected because there was not a statistically significant difference in environmental performance according to sector. table 7 shows the 5 hypotheses considered in this research and the results from the statistical tests performed on them. in summary, this research suggested that the industries in the research area with iso 14001 certification had a better environmental performance than those without it, as expected. the same conclusion was extended to those companies with iso 9001certified quality systems even in the absence of iso 14001. it was possible to conclude that multinational firms implemented more environmental friendly practices compared to brazilian national companies. size mattered to environmental table 5. spss output for a one-way anova test on h4. sum of square df mean square f sig. between groups 343.190 3 114.397 5,492 .002 performance within groups 1,229.032 59 20.831 total 1,572.222 62 table 6. spss output for a one-way anova test on h5. sum of square df mean square f sig. between groups 53.361 3 17.787 .691 .561 performance within groups 1,518.861 59 25.743 total 1,572.222 62 table 7. summary of the tested hypotheses and their respective results. hypotheses status reason h1 h2 h3 h4 h5 companies with iso 14001 certification have better environmental performance than those without it. the discipline imposed by certifications other than iso 14001 positively influences environmental performance. multinational companies have better environmental performance than brazilian national firms. firm size matters. companies belonging to the auto industry have better environmental performance than those in other industrial segments. accepted accepted accepted accepted rejected the independent t-test demonstrated that if the null hypothesis was true, the results were improbable because t(61) = 2.47; p < .016. the independent t-test verified that if the null hypothesis was true, the results were improbable because t(34) = 2.54; p < .016. the independent t-test established that if the null hypothesis was true, the results were very improbable because t(61) = 3.27; p < .002. the f test (anova) corroborated that if the null hypothesis was true, the results were very improbable because f(3;59) = 5.49; p < .002. the f test (anova) proved that the null hypothesis could not be rejected because f(3;59) = .69; p < .561. performance, but only when comparing small companies to the other sizes considered. finally, no significant environmental performance differences could be perceived among different sectors of industry. conclusion the accelerated urban expansion observed in the research area has made the reduction of the resulting environmental impacts a crucial objective to sustainable development. the industrial sector has been challenged by environmental authorities to make a significant contribution to efforts to reduce pollution in the area, by imposing stringent environmental requirements. however, the results of the survey presented in this study suggested that general actions taken by industries to combat the environmental challenges have been effective and surpassed the mere shallow environmental wording. companies have shown more environmental concern than the “must do” requirements imposed by legislation, as the actual practices observed transcend legal demands in several aspects. in fact, the results indicated that the environmental performance of the companies considered in this research reached a 46point mean (against a maximum of 55). furthermore, several of the environmental practices reported by the firms were broader and more environmentally friendly than those required by local environmental authorities. the research also highlighted the general characteristics of the companies most committed to the utilisation of best environmental practices. these companies are iso 056 afr. j. environ. econ. manage. lucato et al. 057 14001certified or had at least an iso 9001 certification and were usually multinational firms that were not small in size and belonged to no specific industrial sector. the findings presented here are also subject to some limitations. the validity of the proposed environmental performance measures should be verified by further research comparing it with similar indices that are already being used. this step was not performed here because proposing a new method to measure environmental performance was not the central focus of this work. second, the initial questionnaire answered by the researched firms should be followed by a more in-depth interview, in which much more detailed information could be obtained to shed light on specific points not covered by the present survey and create a more meaningful analysis. future research will consider this approach to report on amore detailed analysis. acknowledgement the authors are grateful to the research backing fund from uninove – universidadenove de julho. references angell lc, klassen rd (1999). integrating environmental issues into the mainstream: an agenda for research in operations management. 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environmental economics and management issn 2375-0707 vol. 6 (1), pp. 355-366, january, 2018. available online at www.internationalscholarsjournals.org © international scholars journals author(s) retain the copyright of this article. full length research paper approach to resolving pollution of river water associated with human activities in tanzania bomani saida sumari institute of resource assessment, university of dar es salaam, p. o. box 35097, dar es salaam, tanzania. e-mail:bomani.sumari@hotmail.com accepted 17 march, 2017 lack of coordination among sectors and institutions is among factors that results in ineffective management of natural resources in most basins in east africa including tanzania. in many cases, this has reported to be the most factor contributing natural resources degradation and conflicts between societies. this paper presents findings on different factors affecting the sustainability of the mara river basin (mrb) and proposes a management framework that will bring about sustainable resources use in the basin. the study was limited to the mrb part of tanzania and multiple approaches were used in data collection. the mrb is experiencing a number of management problems including deforestation, land degradation and pollution of the river water associated with human activities. institutional framework for natural resource management (nrm) is rather sectoral thus lacking integration and sometimes results into conflicting efforts to conserve natural resources. it is evident that some cultural attitudes including gender have positive impact on natural resources management such as the customary land tenure system. for sustainability of the mrb resources, a well coordination of natural resources and livelihoods projects, programs and stakeholders’ participation is a key factor without neglecting cultural aspects. furthermore, different policies need to be considered by linking them together to achieve sustainability. key words: mara river basin, natural resources, sustainable, water resource management. introduction the mara river (mr) is an international river, shared between kenya and tanzania and the river is very potential in supporting community livelihoods in particular through agricultural production (majule, 2008). natural resources (including water, soils, forest, wildlife, macrophytes and others) in most river basins including the mr have been managed in unsustainable manner, thus leading to their depletion and degradation with negative impact to community livelihoods (majule et al., 2009). likewise in other basins, climate change and variability coupled with land use change in the basin affects agricultural production in a number of ways including declining crops and livestock production (salinger, 1992; frederic, 1997; majule, 2008; lema and majule, 2009; kangalawe and lyimo, 2010). main reasons for resource depletion have been mentioned to be due to population increase, high poverty incidences, lack of coordination in managing resources between sectors and also due to poor technology and lack of incentives (kangalawe and lyimo, 2010). stakeholders in the basin are increasingly facing problems with poor water quality and environmental degradation in particular soil erosion and compaction (reij et al., 1996) leading to declining crop productivity and thus limiting efforts to achieving poverty alleviation, improving health and food security. in this case, economic development and protection goals of the natural resources are negatively affected and this requires an understating on both social and biophysical characteristics of the basin in order to formulate appropriate interventions (salinger, 1992; yanda et al,. 2005; kangalawe and lyimo, 2010). main issues include the loss of forest cover in the upper catchments and along rivers, unsustainable agricultural expansion and intensification (including small scale irrigation), population growth, poorly planned water abstraction, pollutions from mining, agriculture and inappropriate fishing methods. a review indicates that different projects have been initiated in the mrb to address socio-economic economic, cultural and environmental concerns. for example, the mrb project was developed to serve as a catalytic agent for bringing various stakeholders within and outside the basin to the discussion table to exchange ideas and bomani 356 figure 1. location of mara river basin (source, ira cartographic unit). information for planning and implementing shared sustainable management and conservation initiatives. it has been realized that there is a growing need for generating baseline data prior implementing different development programs in order to make sure that development activities does not really compromise with natural ecosystems (yanda et al., 2007; majule and kalonga, 2008; majule et al., 2009).for sustainable management and development of re-sources of the mrb, there must be political commitments from the governments of tanzania and kenya and sup-port stakeholders’ dialogue to develop a shared vision, mission and objectives. this means that tanzania and kenya needs to develop a management framework that will supervise the implementation of social economic activities taking into account that what ever activity is implemented in the upstream part has no significant impacts socially and environmentally downstream. for example how do you manage agricultural production and livestock keeping in the upper catchment to minimize water pollution and siltation downstream? this requires a compromise between the two countries that share the basin. a baseline study on socio economic and cultural aspects on the mrb was therefore intended to provide different stakeholders and scientific community information that can be used in the planning of different development activities such as mining, expansion of irrigation, sustainable livestock keeping and other investments on wildlife management. mrb is endowed with a number of natural resources which are undergoing degradation due to several factors. a coordinated planning in managing such resources was therefore revealed to be necessary and thus a need for such study. the paper presents facts about socio-economic, cultural and environmental concerns on the sustainability of the mrb and used such information to emphasize a need to developing a well coordinated framework for managing natural resources in a sustainable way (mcdonald and kay, 1988). this paper also provides a comprehensive analysis of best and poor practices that enhance sustainable planning of the management of the mrb natural resources in particular water. this paper also discusses and proposed the institutional framework for managing natural resources in a sustainable way in mrb and ascertained how socioeconomic activities, cultural aspects contributes to resource management. the environmental implications associated with resource management and policy interventions that could be adopted in other basins have also been highlighted for policy implementation. description of the study area geographical locations the mr is an international river, shared between kenya and tanzania in east africa. the size of the mrb is about 13,750 km 2 , of which about 65% is located in kenya and 35% in tanzania. the basin is located in the northern part of the country and is shared with kenya on the upper stream part (figure 1). the mara river drains its water into lake victoria and the basin covers musoma, tarime and serengeti districts in tanzania. climate and soils the mara region is divided into three major climatic zones namely; i) the northern zone which falls within the mrb in highland area covering tarime and part of serengeti districts. this zone receives an average rainfall of between 1250 and 2000 mm per year and it has two rainy seasons; a short one from september to january, and a long rainy season from february to june. this zone favors he growth of different annual and permanent crops including beans, maize and coffee respectively; ii) the central zone which covers much of musoma district and eastern parts of serengeti districts. the zone receives between 900 and 1300 mm of rainfall per year and it favors the growth of different crops including rice, maize, sorghum and many others; iii) the last zone is lowland area which includes much part of the bunda district that does not fall in the mrb. the region’s soils have been formed by weathering of granite rocks resulting into a wide range of soil types. generally, soils vary from course and light to heavy and fine textured soil. other soil inclusions include light sandy loams, grey clays particularly in the valley bottoms and in wetlands and black calcareous soils referred to as mbuga soils. the later are located in the lower part of the basin and are naturally very fertile supporting the growth of different crops. geology according to de pauw (1984), geologically the mrb is a flat sheet of dark grey basalt associated with metavolcanic rocks. the rocks belong to pre-cambrian age forming a base for the formation of younger rocks. mara region has been classified into three portions on geological basis. 1. northern highland: this occupies the whole of tarime, parts of serengeti and musoma and it consists of granite granodiorite foliated gneisses and magnetite. 2. southern highlands: this occupies the western parts of serengeti and large parts of bunda district. it consists of mainly volcanic rocks of alkaline nature 3. central lowland: mainly in serengeti and parts of bunda and musoma. it is of meta-volcanic nature having conglomerates. they also dominate in southern side of the mara river. topography and drainage mara region lie between the low granite hills rising at about 100 m above the gently sloping foothills, which lead down to rather narrow flooded areas of musoma point, and makoko foothills (urt, 2003). other parts of 357 afr. j. envir. econ. manage. the region are the areas in which plateau surface is broken up by long narrow hill ranges, which rise above rather flat low lands. there are several hills, which are within the region’s area including the ryamakongo hills, which rise up to 1259 m.s.l, kibayo hills 1254 m.a.s.l, and nyabisonga hills. generally, the topography of the region is undulating to rolling with wide valleys and occasional steep sided hills and this allows for different livelihood systems to interact within and across ecological gradients (majule et al., 2009). the mr is the only perennial river in the basin and it forms the major drainage pattern in the region with its tributaries flowing to lake victoria. other streams flow to the lowlands forming flood plains which are potential for livestock grazing as they provides water and favors pasture growth for livestock grazing (figure 2). study methodology this study used both secondary and primary data. secondary data collection involved review of existing reports (unpublished, gray and published reports) from libraries and documentation centers in various institutions in dar es salaam and mara region. some reports were also made available through internet search. secondary information were supplemented by primary data at district level whereby small meeting were made with district commissions, district executive directors, district planning officers, district agricultural and livestock development officers, district natural resource officers and community development officers for musoma, tarime and serengeti districts. in this case at total of 18 stakeholders were consulted in total for all three districts. since the study had to be conducted in a limited period of time, the parti-cipatory rural appraisal was employed where by a checklist with few key questions was used to collect required information. the method’s cornerstone was interactive learning, knowledge sharing and assurance of high local people’s participation. the participatory research approach methods were applied to quickly generate additional information through transects walk (chambers, 1992; kangalawe et al., 2005; majule and mwalyosi, 2005). the interviews with leaders at district level took place in an informal way where only some of the questions were predetermined and the rest arose during the interview. the study also involved visiting of some specific areas for physical observation on how natural resources are being managed and implications on the ecosystem. such areas include a number of hotspot areas such as a gold mine at nyamongo, farmlands and selected forestry patches in the mr flood plain and villages situated nearby. in the village a total of 15 community members attended at focus group discussion including a village executive officer (veo) and a village chair person. on the other hand, at the nyamongo mining, a total of 5 people were involved in the discussion including company manager, an administrative officer, 2 geologists and a waste management expert. the information collected consolidated this paper about mrb. due to the scope of this study, data collection was limited to tanzania part of the mrb. results and discussion socio-economic characteristics the findings reported under this section are purely based bomani 358 figure 2. part of the degraded simoni riverline forest in ikongo area (photo by majule, 2008). on review and consultations made between a researcher and district leaders and few other stakeholders consulted at community level. administrative issues it is estimated that about 65% of the mrb is in the kenyan side and 35% in the tanzanian side. in tanzania, the basin falls under mara administrative region which is divided into four districts namely musoma, tarime, bunda and serengeti. bunda is the only district which does not fall in the mrb. the mrb has a total of 16 divisions, 97 wards and 336 villages by the time of this study. according to the consultations made, currently there is no coordination in the planning and management of common resources found in the mrb. for example, planned activities on water resource use by abstracting water from the mr for hydropower development on the kenya side is likely to have large impacts on the ecology of the mara river and consequently on lake victoria. this or any other development initiatives in the upper part that will entail water use from mr are also likely to have implications on community livelihoods downstream. under such a situation a cross border integrated planning on resources use and management is very important for sustainability of the mrb ecosystem and community livelihoods. the proposed amala weir water diversion project and the shelved ewaso_ngiro hydropower project will significantly reduce water quantity and completely drying of the mara river under severe drought. implications of this development on the kenyan side would have severely affected the serengeti ecosystem and the livelihood of the people on the tanzanian side. other initiatives that can be seen as opportunities include the involvement of east african community and the nile basin initiative (nbi) in particular the mara river basin project under nbi. moreover, there is lake victoria basin water office at the national level that deals with management of water resources in the basin part of tanzania. figure 4 proposed a best implementation framework for sustainability of natural resources in the basin. although there are policy frameworks governing integrated approach in managing natural resources in the basin, it is evident that in practice there is lack of coordination in planning and management of natural resources in the mrb. a common practice is that each of the three districts is fully mandated in the planning and management of various natural resources found in their respective territories. it is often the case that most of the ecological units are cross border resources and are managed differently and management plans therefore do not complement each other. for examples, the river itself and pockets of forests located in ikongo area are shared by more than one district but managed using different approaches. under such situation, it has been found that lack of integrated approach in natural resource management among the three districts has contributed to the on going degradation of natural resources in the basin ecosystems. typical examples of problems observed to be associated with lack of integration in resource management include; 1. the serengeti district council is currently implementing a strict by-law, which restricts large scale charcoal burning while the neighboring districts of tarime and musoma are not implementing such by-law. as a result, charcoal business is mushrooming in the tarime and musoma districts leading to further forestry degradation. 2. the remaining part of the simoni riverline forest at ikongo area (figure 2) is only found on the serengeti side while on the tarime district side has been completely cleared and converted into grazing and cultivation. integrated planning must be extended to lower administrative units such as wards and villages. for example, more than one village located in the kisaka ward shares the ikongo forest within serengeti district. apparently, it is buchanchari and nyansurumunti villages in only that have taken strong initiatives to conserve resources in the mrb. the strategy used includes prohibit tree cutting for various uses, use of forest for recreation purposes, and set of a fine of $10 (tshs 10,000) for offenders violating these by laws. ethnicity, cultural characteristics in the mrb, there is diversity of ethnicity that is associated with different cultural attitudes with various impacts on natural resource management. the dominant ethnic groups in the mrb are wakurya, wajaluo and wajita (urt, 2003). in tarime and serengeti districts, the dominant ethnic group is wakurya. they occupy the major fertile land in the districts manly in highlands. wajaluo are also found in parts of tarime district. wajita are dominant in musoma district and other small tribes such as wazanaki, wasuba, waikizu, waisenye, waikoma, wangoreme, wakwaya, waluli and washashi also characterize the region’s ethnicity picture. wakurya is a native tribe and has maintained its culture over decades and this has strong impact on management of land resources. for example, this study revealed that land is owned by clans thus it is difficult for the village government to plan on how land can be used. on the other hand, such land tenure system seems to be effective in that they the owners have security over land resources and they can therefore manage it appropriately. in such a situation it is hard to find deforestation taking place by outsiders. they have regulations and rules on how land resources can be managed. this practice should be seen as an opportunity in natural resources management perspectives. on the other hand, the clan system has large impact on population size in tarime district. this is because clans are confined in defined geographical areas, densely 359 afr. j. envir. econ. manage. populated and thus restricting movement of people from one area to another area occupied by a different clan. the only interaction (outlet) is through marriages. under circumstance that the population in a clan is large enough, resource degradation is likely to occur. in this regard, people are forced to move to the neighboring districts such as serengeti searching for agricultural land and pastureland. this is a threat to mrb management. culturally, most ethnic groups in the mara region are agro-pastoralists and they value the number of livestock as a sign of wealth and a symbol of status in the society. as a result, large herds of livestock particularly cattle are found in the basin. the survival of livestock depends largely on mara river resources particularly water and pasture. excessive livestock keeping is a threat to the basin ecosystem. in terms of gender, there is also a significant division of labor and resource ownership based on gender. for example most of the land is owned by male while female undertake most of the farming and household activities including for example firewood collection. it was also noted that most of the fishing, miming, hunting and charcoal business, livestock keeping are done by young and middle aged male. male are in most cases the head of households but there also very few females who head households (less than 5%) and there are those who tends to own another female to work for them through “nyumba nyitu” arrangements. within the basin there are pockets of forests on water sources, which are used as sacred sites. such cultural believe environmentally friendly because water and forest resources are protected. such areas may also be of biodiversity importance similarly to what has been reported elsewhere (yanda et al., 2005; kangalawe et al., 2005; majule and mwalyosi, 2005). population characteristics the 2002 census report provides population data of mara region (urt, 2003). the region had a total population of 1,368,602 people of which 715,153 were females and 653,449 males (table 1). average household size is 5.5 members and the annual average population growth 1988-2002 was 2.5% (urt, 2003). the 1988 population census placed mara as the seventh most densely populated region after dar es salaam, mwanza, kilimanjaro, mtwara and kagera at 43.7 persons per square kilometer. however when we exclude the serengeti national park area, the population density of mara region increases to 76 people per square km making mara region the fourth most populated region in mainland tanzania. due to high population density, competition for land between cultivators and herdsmen is escalating and deforestation marches on at an alarming rate (urt, 2003). competition for land resources eventually contribute to land degradation and consequently bomani 360 table 1. population structure at district level in the mrb. district total populations growth rates 1967 1978 1988 2002 1967/78 1978/88 1988/2002 musoma 196,625 263,129 316,632 330,953 2.7 1.8 2.4 tarime 188,536 253,010 333,888 492,798 2.7 2.8 2.8 serengeti 158,984 207,688 111,710 176,609 2.4 7.5 3.3 source: urt (2003). table 2. major livestock distribution in the mara river basin. type of livestock district musoma serengeti tarime cattle 272,635 199,533 307,694 goats 90,606 307,694 150,300 sheep 40,257 150,300 69,265 donkey 1,698 432 2,738 source: urt (2003). change the catchment’s hydrology such as infiltration characteristics which brings about soils and river bank erosion which was observed during field visit during this study (table 4) . major economic activities major economic activities in the mara region and particularly the mrb are agriculture, livestock production, fishing, mining and business and trade. mara region communities rely on livestock production and ownership predominantly cattle, goats and sheep to fulfill social as well as economic needs. livestock sector is the second most important contributor to the region’s economy. it is estimated that 51% of total agricultural households in mara region keep cattle and the size of herd per household ranges from 50 to 1000 cattle. animals represent a bank stock, to be purchased when there is good harvest and sold during distress times in order to buy food. cattle and donkeys are widely used for transportation of crops and other domestic goods and for ploughing. however, over the past decade, the occurrence of erratic rains and livestock distress, sales have tremendously reduced the quantity of livestock in mara region to the extent that very few households now own cattle. cattle ownership is more widespread in the midlands agropastoral communities. table 2 shows livestock population in the three districts. most of the livestock kept in the area is grazed in the mrb, particularly in the flood plain during the dry season due to water and pasture availability and grazed in the uplands during the rainy season. there is no proper land allocated for grazing which is one of the major setbacks in pasture and water management in the basin. in tanzania the agricultural sector contributed 48% of the countries gross domestic product (gdp) and about 65% of the total foreign exchange earnings in 2000 (urt, 2000). food crops grown in the region include: cassava, maize, sorghum, finger millet, paddy, sweat potatoes and beans. production trend of food crops is shown in table 3. cash crops grown in the basin include: cotton, coffee, sunflower, tobacco and groundnuts. production trend of cash crops is shown in table 3 fluctuating yields are probably due to the fluctuation of weather conditions in the region. average individual annual income (per capita gdp) in mara region had improved from us$ 142 in 1995 to us$ 226 in 2000. irrigated farming in mara region is not common although it is feasible considering the existence of lake victoria and mara river. currently, individual households, growing mainly vegetables, do irrigated farming on a very small scale. fishing provides employment for people along the lakeshore generating good incomes and sustains the fish trade within and outside the country. however, fishing contributes little to the region’s economy compared to crop production and livestock keeping. trade and industry do not have much significant importance to the region’s economy. there is no reliable status on the catch volume and income generated from fishing in the river. most of the available information refers to the catch volume from the lake. this is because fishing in the river is not considered to contribute significantly to the economy of the region. mining research conducted in the region has revealed that the region is rich in minerals, mainly gold, kaolin, limestone and gemstones. currently, both artisanal and 361 afr. j. envir. econ. manage. table 3. production of major food crops in mara region. crop/year 1996/97 1997/98 1998/99 1999/00 2000/01 2001/02 year average cotton 21852 22846 5580 3003 22433 19095 17559 coffee 1651 2011 2009 4077 2344 36 2585 tobacco 65 75 600 190 n.a n.a 233 sunflower 40 149 68 18 240 100 134 groundnuts 1450 154 848 512 1738 490 960 total 25058 25235 9105 7800 26755 19721 21471 source: urt (2003). large-scale miners are operating in mara region (buhemba in musoma and nyamongo in tarime districts). artisanal mining is operated in areas around the largescale mining at a small scale and is operated illegally. large-scale mining operations are conducted by afrika mashariki co. ltd in nyamongo and meremeta co. ltd in buhemba. data on incomes generated by private companies from gold were not made accessible. the only available data is of early 1990s when gold was purchased by the bank of tanzania from small-scale miners. existing institutional framework for managing natural resources it should be pointed out that mrb is shared between tanzania and kenya; hence an effective management approach should consider the entire basin. management of the tanzanian part of the basin will not be effective because it is the lower end of the river system, since mismanagement on the kenyan side will have pronounced effect on the tanzanian side. similarly, the tanzanian part of the basin should also be managed in an integrated manner. the current local government reform has given district councils full mandates to plan and implement various development activities including management of natural resources. figure 3 illustrates the existing institutional framework at district level. the existing framework has both strength and weaknesses. major strength includes the coordinated ability the structure has in that all the sectoral directives from various ministries converge into district executive director’s (ded) office. various technical personnel representing key sectors support the ded thus ensuring integrated approach in the planning process. the existing institutional framework (figure 3) is intended to facilitate effective planning and implementation of various activities on the ground by ensuring that there is both top down and bottom up communication. however, lack of extension officers for some key sectors at the grass-root level is one of the limitations associated with this framework. for example, there is no extension staff on water resources, land and other natural resources at the village level. there are some management efforts in place such as serengeti national park though it covers only a segment of the basin. lake victoria environment management project is another regional management initiative. however, this management initiative is project oriented in that its activities will be implemented within a given time frame. a summary of key issues affecting resource management in the mrb this study has revealed that most of socio-economic activities (table 4) undertaken in the area have a large impact on mrb ecosystem. the study identified a number of natural resources management practices undertaken within the mrb. in general, human activities have been identified through consultations to have significant implications on natural resource sustainability and productivity as indicated in table 4. this cause effects relation enabled a researcher to propose appropriate interventions which can also be applied elsewhere with similar conditions. community involvement in resource conservation and management the land tenure system of kurya ethnic group provides a good footing for community involvement in natural resources conservation and management. the clan regulates management of land resources. in this regard, these ethnic groups need to be facilitated by advocating for appropriate management approaches. it should also be pointed out that the initiative taken to ban charcoal making in the district is a lesson to learn and can be applied to all the districts. however, a caution is that such decisions should be effective only if alternative source of energy is given. also, the initiative of buchanchari village to conserve the forest at ikongo area is a testimony that if the villagers are coordinated they can come up with effective management plan for their own resources. there are several initiatives taken by district authorities that aim at resource conservation and management. for bomani 362 figure 3. institutional framework for managing natural resources at district level. table 4. key issues that need solution for sustainable mrb management and development. practices responsible actors in established impacts/threats proposed interventions addressing the problem -excessive water abstraction from the mrb river -deforestation along mara river -cultivation and grazing along the river bank -illegal fishing practices -use of chemicals -fishing in breeding points -mining companies -crop irrigators -livestock keepers -local communities, local governments, ngos, cbo, forest departments -local communities, river basin offices, agricultural research institutions, local governments (daldos) -fisheries and livestock -departments, fish traders, local communities, ngos, cbo -water disposal mechanisms is questionable -water pollution -this is a threat to environment in particular soil erosion, loss of carbon and global warming, loss of species and diversity -enhancing river bank erosion and river siltation -raises great concern to human health and water quality -destroy breeding sites -develop integrated water resource management (iwrm) plans -abide to water allocation schemes conservation of water sources -provide education to the communities on tree conservation -introduce tree planting schemes encourage agroforestry practices -develop village land use plans -undertake research on appropriate practices -develop by laws on river bank use -establish by laws on illegal fishing -education on better fishing practices -poor agronomic local communities practices -illegal wildlife hunting in forestry patches (ikongo local communities, hunters area) and game reserves -threats to the land and river -train communities on better siltation, soil fertility loss agronomic practices -introduce alternative sources of income -threats to both large (buffaloes) -training in wildlife resource and small mammals management -involve communities in managing wildlife table 4. contd. -un controlled fire -local communities -loss of species of ecological -education on impacts of fire (hunters, cultivators, significance and loss of soil fertility -establish by laws on fire livestock keepers) -small scale gold local communities -threats to water quality, land -control small scale mining activities mining particularly degradation (development of bad by providing appropriate guidelines in mara lands) and technologies source: fieldwork and consultations with stakeholders. example, a number of bunds to trap water in the subcatchments for irrigation are being constructed in all the districts through funding from the central government. this effort is a result of the mara farmers initiative project (marafip) concluded in 2002 (urt, 2003) and it aimed at enhancing food production, particularly rice as food and cash crop using the available water resource. similarly, a number of watering points for livestock and dips are being developed in the various districts. also, more watering points and dips are planned for future development. such efforts aim at promoting livestock production, as it is the major activity in the basin. furthermore, appropriate distribution of livestock watering points and dips is necessary to ensure even distribution of livestock, thus reducing effects of degradation in concentration areas due to trampling and overgrazing. furthermore, village governments in tarime and serengeti districts are implementing wildlife management areas (wma) on pilot basis. this is seen to be a sustainable way of managing resources in parts of the mrb. the economic gains from such program support development activities and needs to be sustained. management of water resources in the mrb there are three major sources of water in the mrb. these include water from the river mara, water harvested in micro catchments draining into the main river water systems and borehole systems. water from the main river systems is used for mining activities in africa mashariki gold mine whereby water license permit allowable abstraction rate of 4200 m 3 /day, and current average daily usage is about 3200 m 3 /day. out of that, nearly 60% is recycled into the production system. this is the only large water abstraction activity in the basin. other uses of water from the river include livestock and wildlife, domestic use and small-scale irrigation. all these activities use small amount of water. water collected in micro-catchments is used for irrigation (mara bands), livestock and domestic use. for example, in serengeti alone there are 2 dams (iseresere and nyamandicha) constructed by marafip and about 27 chaco dams constructed by different stakeholders. the responsibility of water resource management currently rests under the power of the ded (figure 3). however, the relevant technical personnel will do technical undertakings. for example, agricultural experts are involved if water is to be used for irrigation while livestock experts are involved if water is collected in dams for livestock drinking. one of the major problems is lack of technology to abstract significant amounts of water for various uses. for example, watering cans, small furrow canals and small powered water pumps are used to draw water from the river. presently, local communities do not realize water quality to be a problem. however, there is a growing concern from the regional and districts authorities that water is being polluted from different sources mainly gold mining and fishing by using illegal chemicals. with regards to the gold mining, the effectiveness of the waste disposal dam has not yet been monitored. what is more worrying is the artisan type of mining involving the use of mercury in gold extraction since the process is undertaken in streams draining into the main river system. impacts of socio -economic activities on the hydrology and other resources of mrb a link between major economic activities and hydrology in the mrb is that the landscape characteristics determine the hydrology of the river system. on the other hand, socio economic activities can modify natural landscape characteristics and thus altering the river hydrology. for example, land degraded due to intensive crop cultivation and overgrazing enhances surface run off, less water infiltration, accelerates evaporation in a way reported by scwab et al. (1993). in such a situation the river experiences less flow during the dry season, deforestation of riverline forest encourages riverbank erosion, desiccation of the wetlands, which are important habitats for flora and fauna, and wetland degradation also reduces buffering and water storage capacity of the wetlands. wetland degradation due to poor farming practices has also been reported by majule and mwalyosi (2005) in the rufiji river basin. the impact of socioeconomic activities on the basin hydrology as pointed out above is presently visible in the area. for example, high 363 afr. j. envir. econ. manage. bomani 364 table 5. pair wise ranking of different impacts on hydrology and natural resources due to human activities. number impacts identified total score rank (position) 1 deforestation and degradation of forest 8 1 2 drying of wetlands and other water sources 6 2 3 declining of soil fertility 5 3 4 siltation of the mara river 3 4 5 pollution of the mara due to chemicals 2 5 6 soil erosion 2 5 7 conversion to bad land due to mining 1 6 8 soil compaction 1 6 source: field pair wise ranking (2008). concentration along the river system has contributed to the degradation of immediate catchment areas through overgrazing and trampling. such practices could lead to severe degradation if measures to control livestock movement are not taken. a study conducted by yanda et al. (2005) in the bahi basin revealed a need for controlling livestock numbers to meet the carrying capacity in wetlands and this also apply in the management of mb resources. furthermore, livestock water drinking directly to the river system is causing riverbank soil erosion. cultivation very close to the riverbank was also found to be common thus enhancing riverbank erosion. on the other hand, the ongoing bush fires and deforestation (for charcoal, fuel wood and building materials) reduces vegetation cover thus impacting the river system hydrology as pointed out above. a focus group discussion using pair wise ranking approach at ikongo village provided information on how different socio economic activities have negatively affected the hydrology and other resources in the basin. the analysis (table 5) revealed 8 major impacts on hydrology and natural resources of the mrb that is associated with social economic activities. deforestation and forest degradation scored the highest and this was followed by drying of wetlands and declining of soil fertility. siltation of mr scored fourth and this was described to be associated with removal of vegetation cover in particular deforestation and cultivation near river banks. siltation is common in most great rivers and has also been reported by majule and mwalyosi (2005). other impacts reported were pollution of mr water due use of agricultural chemicals in particularly fertilizers and chemicals for fishing as well as use of chemicals by both small and large scale miners. interventions in addressing such problems should be part of the management issues for mrb indicated in figure 4. proposed framework for sustainable natural resources management in the mrb to ensure that water resource is properly managed at basin level, the government of tanzania has developed a structure on which river basins under the ministry of water has a mandate of managing water resources effectively (figure 4). the foundation for the implementation of the new guidelines in the water sector in tanzania is the water sector development plan (wsdp) (urt, 2007) and its implementation manual in its updated version of 2007. in this case, the development of the program for the three elements of the sector is explicitly considered. the framework shown in figure 4 is also applicable in the mrb and this also need to be applied to the upper catchment areas in kenya part but should not compromise with the existing structure. policy implications on mrb management environmental conservation has to be analyzed in the context of the relevant policies governing management of natural resources and sustainable livelihoods. table 5 presents a summary of key policy issues in terms of opportunities and constrains that need to be taken on board in addressing legal aspects to the planning for conservation of mrb. conclusions agriculture and livestock keeping are the major socioeconomic activities in the basin. it is these activities that have adverse impact on the ecosystem. mrb is experiencing a number of natural resource management problems including deforestation, land degradation and pollution of the river water due to mining and illegal fishing using poison. the management approaches seem to be sectoral, thus lacking integration. local community involvement in natural resources management is also not properly co-coordinated and therefore less effective and conflicting. it is evident that some cultural attitudes have positive impact on natural resources management such as the customary land tenure system in the kurya 365 afr. j. envir. econ. manage. ministry responsible for water national water board regional secretariat basin water boards basin water offices district councils catchments water committees catchments water offices sub-catchments water legend committees ppeals delegated authority wrm responsibility sub-catchments water offices planning process representation water users’ associations statutory/autonomous bodies wat users figure 4. relationship between different institutions in water resource management in tanzania (source urt, 2007). community. despite of promising efforts both in terms of policies and strategies for managing natural resource in the mrb, knowledge sharing across basins is still needed to manage shared resources in particular water effectively. other factors including climate change impacts, vulnerabilities and adaptation strategies needs to be considered and then integrated into the basin management framework. acknowledgments author wishes to thank wwf-tanzania for providing financial assistance to undertake this important study. mara region authority is thanked for allowing this study to be conducted in their region that involved discussion with various stakeholders on key issues. districts authorities in particular musoma, tarime and serengeti are thanked for availing information in the form of reports, spending their time to discuss various issues with study team during the field visit. finally, the author wishes to thank all village leaders and local communities and individuals who participated in the field visit to identify various issues. references chambers r (1992). rapid appraisal: rapid, relaxed and participatory. discussion paper no. 311, ids publication, university of sussex, brighton, england. de p (1984). soils, physiography and agro ecological zones of tanzania. a consultant report submitted to united republic of tanzania. frederic k (1997). “water resource and climate change”. climate issues brief 3. resource for future. washington dc, usa. kangalawe rm, lyimo j (2010). population dynamics, rural livelihoods and environmental degradation: some experiences from tanzania. environment and sustainable development. doi 10.1007/s10668010-9235-y. kangalawe rm, majule ae, shishira ek (2005). an analysis of land use dynamics and land degradation processes in the great rift valley, central tanzania: a case of iramba district”. book published by ossrea. isbn 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presidents office, dar es salaam, tanzania. united republic of tanzania (urt) (2003). mara region farmers initiative project (mara-fip). final project completion report. bsf grant no. bg 017 tz. united republic of tanzania (urt) (2003). mara region socioeconomic profile. published jointly between the national bureau of statistics and mara regional commissioner. united republic of tanzania (urt) (2007). water sector development plan (wsdp) final version. ministry of water and irrigation. yanda pz, mung’ong’o, c, majule ae (2007). integrated management plan for the malagarasi-muyowozi ramsar site. final consultant report submitted to ministry of natural resources and tourisms, wildlife division, tanzania. in ternationa l scholars journa ls african journal of environmental economics and management issn 2375-0707 vol. 6 (2), pp. 406-412, february, 2018. available online at www.internationalscholarsjournals.org © international scholars journals author(s) retain the copyright of this article. full length research paper prevalence of environmental degradation in natural resource management philémon mafany george department of geography, university of yaounde i, e.n.s. annex bambili, p.o. bamenda, north west province, cameroon. e-mail: mafany.george@gmail.com accepted 04 december, 2017 the predominance of environmental degradation in africa has generated waves of concern from international and national non-governmental organizations (ngos). since the 1990s there has been a remarkable increase in the number of ngos with environmental protection interest in the south. the paper appraises the involvement of ngos and stakeholder community in environmental protection projects in terms of resource mobilization, organizational strengthening and the institutional development of civil society. the paper which is a product of field investigations concludes that these ngos are having a significant impact on the social, political and economic life of their populations. however there is the question of their sustainability as local ngos derive most of their inspiration and resources from ngos in the north. there is need to appreciate the issues surrounding capacity building beyond technical and sectoral aims. capacity building must contribute to the long-term organizational strengthening and institutional development of civil society as a whole. key words: ngos, civil society, sustainability, environmental protection, participation, appraisal. introduction the past decades have seen steady growth of nongovernmental organization (ngo) at the local, national and international level along with an increasing interest from both donors and the ngos themselves in seeking ways to make ngos more effective. the profile of ngos has grown among policy-makers, activists, and researchers in both north and south (abongwa, 1999). ngos now feature prominently in discussion of service delivery, advocacy and lobbying, social movements, philanthropy and charity giving, building civil society, and social entrepreneurship. this rich diversity of ngos in both the north and the south is widely celebrated, with a growing number of publications devoted to them. although there are voices challenging the claims which are made for ngos, these are generally restricted to the context of humanitarian assistance in emergency situations and ngos continue to be “flavour of the month” in development circles (ired, 1998a). there has been a general and rising interest among countries on environmental issues, most especially environmental protection, since the united nations conference on environment and development (unced) or the earth summit, held in rio de janeiro, brazil in jane 1992. theoretically, this conference expected countries to recognize the rather complementary relationship that exists between development and the environment. the challenge of environmental protection was made formal by the cameroon government’s recognition of ngos as partners in natural resource management and rural development (ndenecho, 2003). the challenge is that ngos must perform efficiently in realizing local, regional, national and global environment plans, which means they must have adequate capacity and resources (acho-chi and ndenecho, 1994). this requires an appraisal of the financial means, sustainability of ngos, cooperation between ngos and gos (governmental organization) in tackling natural resource management, the focus on the grassroots resource users, the degree of participation (empowerment) and the global dimension of the reflection /activities of ngos. this paper seeks to identify ngos involved in development work and to appraise the input in the natural resource management process by ngos in order to establish a base for cooperation between local and international ngos and to elaborate strategies in philémon 407 figure 1. core problem identification and strategies employed by ngos in partnership with stakeholder communities (zimmermann, 1996). achieving sustainability through local resource mobilization, organizational strengthening and the institutional development of civil society. study area and core problem the study area is the bamenda highlands. it is characterrized by soaring mountain peaks, plateaux, upland watersheds and intermontane basins. there is a high lava plateau with elevations between 2000 and 2800 m, an intermediate plateau between 1000 and 1900 m, and a low plateau between 900 and 300 m above sea level. the montane forests of the area are unique in that they have one of the highest levels of endemism (macleod, 1986; stuart, 1986). their scientific importance has received both international and local conservation attention from non-governmental organizations (ngos). the up land or hilly watersheds have combinations of forests, farmlands and grazing lands and are densely populated by farmers (96 inhabitants / km 2 ) with and annual growth rate of 2.3% (minpat/undp, 1999) since the early 1990s, road improvements have increased the agricultural value of the area. the increasing population combined with the increased market access has resulted in a much more intensive system of farming without the traditional fallow periods that were used to restore soil productivity. the end result is that crop yields are poor and natural forest is being rapidly cleared to augment impoverished farmland. the new lands are on steep and highly erodible slopes. these scenarios are analyzed in figure 1. the decrease in fallow and encroachment of agriculture on to grassland has led to a reduction in land available for grazing. consequently livestock range freely within montane forest preventing regeneration and threatening some of the best remaining areas. overgrazing and trampling have caused the complete loss of vegetation in some places. serious erosion is now occurring, aggravated by deliberate burning. over the past two decades there has been a noticeable decrease in the dry season water flow and many water catchments are being endangered by the destructtion of the forest (ndenecho, 2006). intensive conservation measures are needed in the area. since the early 1990s there has been a remarkable increase in the number of non-governmental organizations involved in environmental protection in the area. these organizations design and implement land management measures based on the strategies are summarized in figure 1. there is the tendency for these organizations to seek for additional assistance, most often in the form of finances from international donor organizations in the north. research methodology data for this study were obtained from the snv sponsored project by marion wiendels (1994) and a study by ndenecho (2oo3). complementary information was gathered by interviewing one representative of each relevant organization. to be of interest in the framework of this research, an organization had to meet five criteria.  the organization is active in the region at the moment, which implies that co-workers are either established on a permanent base, or are playing an important role in enabling organizations which are physically present to execute their activities. to be included, an organization has to have at least an office based in cameroon.   the organization is not a base organization. a base organization is defined here as an organization existing due to the initiative of the target population.  the organization is either in direct contact with the target population, or works directly with organizations which are in direct contact with the target population.  the organization aims at the development of the area.  the organization is apolitical and non-commercial. these criteria include governmental and non-governmental organizations. an inventory of organizations operating in the domain of rural development and environmental protection in the region was made using an established list of ngos telephone directory and know-ledge of organizations which are active in the region acquired through interviews and field surveys. the study set out to achieve the following research outputs:  an inventory of organizations operating in environmental protecttion and rural development in the region.  the geographical location of ngos in the region  the degree of spatial concentration of ngos in the region  typology and roles of ngos  weakness/limitations of ngos  scope for achieving greater efficiency in sustainable environmental management and protection. a case was made of the involvement of an international ngo (helvetas) in watershed management in collaboration with local stakeholders and beneficiaries at local level. this is the case of the 408 afr. j. environ. econ. manage. tubah watershed protection project (table 1). typology and viability of ngos the field survey established the following typology of development organizations involved in environmental protection issues. this typology will enable us to evaluate the contribution of ngos (figure 2): membership organizations (mo): these are farmers’ organizations and are involved in agricultural development and marketing of produce. the main mos are the cameroon cooperative credit union league (camccul) and north west cooperative association (nwca). mos mainly serve the interest of their members. the problem with some of these organizations is that for a long time they were organized by government officers rather than by farmers themselves and work for farmers but implement government policies. donor organizations targeting communities (dos): these organizations are active in poverty reduction programmes at the grassroots. they started by giving aid to people in distress. unfortunately, most of these have been more successful in instilling a dependency attitude among local people by making them to expect free inputs, tools and credit at favourable rates rather than in emphasizing the importance of improving managerial capacity. the main dos include the north west development authority (mideno) and church organizations. in order to raise finances, they sometimes try to create the image that their target group is in a very difficult situation that will not improve without external support. unfortunately, their target groups include poor people in complex, diverse and risk -prone environments where the agro-ecological and socio-economic situation is very difficult. they evidently lack the capacity to handle environmental and resource management issues under these circumstances. most of them are isolated while others may assign projects to other organizations. community based organizations (cbos): these are very active in the region and include: farmer groups, forest user groups, bee keeping groups, tree nursery groups, common initiative groups, villages development associations, and socio-cultural and development organizations involved in rural road construction projects, rural water supply schemes, community forest management, watershed protection, provision of basic village socio-economic infrastructure and rational use of village natural resources. unfortunately, they face the same limitations experienced by grassroots support organizations because they are championed by local and external elites. international ngos and public service organizations: these are international support organizations. they help membership organizations, cbos and local ngos through financial and material support, training and expertise. these are based in the developed countries but are represented in the study area to provide training and expertise. they also act as a channel to transfer donor assistance to local ngos, cbos and membership organizations. those active in the region include afvp (association française de volontaires du progrès). bird life international, food and agricultural organisation, swiss association for development and cooperation (helvetas), german agency for technical cooperation (gtz), heifer project international (hp!), inades (institut africain pour le développement economique et social), netherlands development organization (snv), and plan international. although operating under different legal statuses these organizations have the common characteristic of possessing high technical capacity and the financial means to implement its policies. local ngos: these are local organizations receiving direct funding from international and northern ngos in order to reinforce local civil society through the development of new partnerships. several proliferate in the study area as there has been an emergence of a new generation of local ngo “contractors” since philémon 409 table 1. inventory of organizations involved in rural development. code abbreviation full name (see figure 2) 1 acsd association camerounaise pour la santé et le dévéloppement. 2 act association for creative teaching 3 adeid action pour un dévéloppement equitable, intègre et durable 4 africa 2000 network 5 afvp association française de volontaires de progrès 6 apica association pour la promotion des initiatives communautaires africaines 7 bird life 8 bvcp bafut village community project 9 camccul cameroon cooperative credit union league 10 catholic church 11 cbc cameroon baptist convention 12 cipcre circle international pour la promotion de la création 13 codidsc comite diocésain de développement et d’activités socio caritatives 14 ded german development service 15 detmac associates 16 eec eglise evangélique du cameroun 17 fao-pam food and agriculture organisation programme alimentaire mondial 18 fimac financement d’investissement de micro-realisation agricoles et communautaires 19 gtz gesellschft fur technische zusammenarbeit 20 helvetas swiss association for development cooperation 21 hpi heifer project international 22 inades institut africain pour le développement economique et social 23 living earth 24 mideno mission de développement de la province du nord-ouest 25 minagri ministère d’agriculture 26 m1nascof ministère d’affaires sociales et de la condition féminines 27 minepia ministère d’elevage des pêches et d’industries animales 28 nwca north west cooperative association 29 oderreb organisation pour le développement rural et reboisement 30 oricaa organisation for rural infrastructure, community animation & afforestation 31 pafsat permanent farming systems and animal traction project 32 pcc presbyterian church in cameroon 33 peace corps 34 prodec programme de dévéloppement communautaires 35 psmp provincial social marketing programme 36 saild service d’appui aux initiative locales de dévéloppement 37 sash sustainable agriculture and self-help 38 setrahac 39 slf sustainable livestock foundation 40 snv netherlands development organization 41 unv-dds united nations volunteers-domestic development services. see figure 2 for the geographical location of the ngos by their corresponding serial numbers. the 1990s. international ngos have more financial resources than local ngos, donor organizations (dos) and membership organizations (mos). they promote a great deal of rhetoric about partnership and enhancing civil society as they channel the majority of their funds to local ngos through semi -contractual arrangements for service delivery projects. there is an exaggerated emphasis on specific sectors and services to the detriment of a wider strategy of funding long-term goals, which cut across sectors, such as poverty reduction and strengthening civil society. unfortunately, these funds are channeled to a very small number of local ngos, thus several local ngos present misshapen organizational profiles. the lack of financial means implies a threatened continuity, poor cooperation among the ngo community, poor integrative approach, and participation. the local ngos have no international dimension. membership organizations such as camccul, nwca and bamenda vega 410 afr. j. environ. econ. manage. figure 2. geographical distribution of ngos involved in rural development (see table 1 for the legend). table cooperation (bvc) dispose of large amount of means and reach many persons in their areas of operation. camccul is limited only to the rural finance sector and isolated in its organizational network. however, its influence in rural savings and credit generation is enormous. nwca used to have a large impact in the development process for it had the monopoly in coffee trade during the period world prices were high. at this moment, nwca faces severe problems in meeting its obligations. the impact of nwca has decreased considerably. local ngos are limited in their sphere of activities as a consequence of the limited organizational profiles. on the contrary international ngos are very active in the area as a result of their high organizational profiles. membership organizations except bvc cover the entire region. the bvc is based mainly in mezam. the spatial influence of international ngos is a result of their policy of support to local ngos through financial assistance and adoption of local ngos and cbos as co-workers. a model of collaboration between ngos and stakeholders the international ngo, helvetas (swiss association for development and cooperation), together with the community development department (cdd) in the ministry of agriculture and a few local ngos, in 30 years have constructed about 350 rural water schemes and 150 water points in the north west, south west and west provinces serving about 1.2 million rural people (zimmermann, 1996). the cdd and ngos as partners of helvetas at execution level design, plan, implement and monitor the performance of village-based water maintenance committees, which operate and maintain the schemes. helvetas and its partners started a comprehensive process of information and sensitization on improved water resource management for water maintenance committees, traditional councils and regional authorities. the villages are the project stakeholders and through their management committees (wmc) and caretakers mobilize local peoples to contribute in kind and cash for construction, maintenance and operation. bigger villages require river intakes and water treatment for which sedimentation tanks and slow sand filters (ssf) are designed and constructed. water intakes are classified as land of common interest and are controlled by local authorities like village and traditional councils. however, with increased agriculture activity in most intake areas and watersheds, water contamination in small streams becomes serious (zimmermann, 1995a, 1995b, 1994a, 1994b, 1994c). the tubah project (figure 3) demonstrates 30 years of experiences in watershed protection by helevetas. some 10 years after initiation the benefits are already being harvested from this project (tah and zimmermann, 1994). philémon 411 figure 3. layout of the tubah watershed management project: model of a holistic approach involving the following sectors: institution building, forest management and conservation, pasture improvement, agroforestry and soil conservation, income generating activities, and a potable water supply scheme. the physical and economic benefits, which will result from watershed improvement or improvement in land use practices, are forest conservation, forest management, afforestation, grazing controls, agroforestry and soil conservation. the ngo’s strategies for watershed management derived from this study include:  development of local institutions: formation of farmers’ groups and federations in programme area, the formation of project and programme committees and training.  ensuring active participation by target population: definition of roles of various population groups, participatory approach for planing decision-making, sharing responsibilities, promotion and communication. this also applies to equal access to benefits for all programme participants and active participation of all in the learning process. women are empowered in land use management and production. this is accompanied by the development of self-help potential for the target population (formation of common initiative groups and creation of alternative income generation).  conflict management: creation of forums and mechanisms of negotiation.  this requires the setting up of a comprehensive and permanent monitoring system to allow proper control of activities in target areas. the role of ngos, local communities and civil society is crucial in achieving sustainable watershed resource management. the strengths of ngos in this direction are impressive but can be exaggerated. local institution building has proved difficult and it is common for projects to fail when ngo staff has departed. a key issue is how to build on local successes in providing services nationally. the danger is that northern ngos will be used even more actively as channels for donor assistance, which would threaten to suffocate the flexibility, independence, and low bureaucratic costs that have made local ngos effective. helvetas is working alongside the government to develop the capacity of national ngos. training, technical assistance, networking to disseminate technical information among local ngos and other activities are being pursued. however, it is difficult for local ngos to know when financial support will be extended to them by northern ngos like helvetas (ndenecho, 2000):  too early and it may weaken the self-help motivation.  too late and it frustrates attempts to move ahead with schemes for water supply. the issue of sustainability and independence of local ngo therefore needs to be addressed. partnership and participation are important in the relation between ngos and the beneficiary communities as they are to those between the ngo and the government. if projects are to be sustainable and yield long-term benefits, communities must be more explicitly involved in design and implementtation and in defining their own contribution. most local ngos operating in the region have sometimes unwillingly incorporated olderstyle management ideas such as strategic planning now dismissed by development workers as having failed to live up to its promise when it was developed in the 1970s rather than heading for the most up-to-date ideas. the most up-to-date mainstreams management theory and practice is now concerned with areas which ngos themselves should be on the top of flexible work teams, reduce hierarchies, building on organizational values and cultures. this should improve their effectiveness and generate new ideas and approaches-once rooted in different cultures and values, and in a genuinely developmental approach to overcoming obstacles to positive social change. discussion and conclusion the community of ngos and civil society organizations is now far larger than they were a decade ago as it is increasingly being felt that they have more advantages than disadvantages compared with government agencies, which perform similar tasks. donors and national governments therefore direct an increasing part of their funds through ngos, which increase the likelihood of dependency on external funding with the risk of being more responsive to donor agenda than the need of their constituencies. the issue of the long-term sustainability of ngos is real. there is the fear that agencies funding ngos in resource poor societies, where there is no evidence of medium-term capacity to absorb these costs, are simply reinforcing what some have termed the “global soup kitchen” or globalization of social welfare. there is therefore a need to focus attention towards the goal of sustainability through local resource mobilization. as of now there is no evidence in the country of such resource mobilization through tax-based state funding, local philanthropic action or income-generating schemes. under such circumstances sustainability is simply a myth. on the contrary local ngos are noted for their dependence on diplomatic services and perpetual support from international donor organizations (ired, 1998b). with globalization and international trade, ngos have become increasingly influential in world affairs and are consulted by both governments and international organizations. these organizations are having a significant impact on the social, political and economic life of their target populations. however there is the question of sustainability as local ngos in cameroon derive most of their inspiration and resources from foreign ngos. in this way both foreign and local ngos serve as agents of recolonisation rather than as liberators as they pose as new missionaries. ngos encounter a number of problems. some local ngos that gain access to official funds through related government projects geared at rural poverty alleviation report encountering confronting bureaucratic bottle-necks in their functioning which creates room for masquerading to gain access to official funds. the majority of local organizations suffer from a weak organizational network. there is need to appreciate the issues surrounding capacity building beyond technical and sectoral aims. capacity building must contribute to the long-term organizational strengthening, or the institutional development of civil society as a whole. local ngos also suffer from management problems. ngo leaders and staff are sometimes too reluctant to think about organizational questions because it might interfere with their primary task of using almost all funds 412 afr. j. environ. econ. manage. for working with poor people and should not spend money on administrative questions. a second set of problems revolves around the view that many ngos are established by people searching for alternatives to mainstream thinking and there is sometimes the feeling that management issues could be dealt with on an ad hoc informal basis may grow in size and develop more complex, multi-dimensional programmes, and suddenly find that they need new ideas, systems and procedures to cope. finally, as local ngos have grown closer to official donors they have been required to develop new systems of accountability and their effectiveness has been questioned and challenged. this has led to the feeling that some of the impetus for the new interest in ngo management has come from the north, and has taken the form of an imposed “marginalization” rather than being part of a local ngo’s own agenda. as a result of the above factors, there is need for ngos to confront the issue of their sustainability and to elaborate new management models. references abongwa jf (1999). modern project proposal writing. maryland printers, bamenda. pp. 50-58. acho-chi c, ndenecho en (1994). rural development survey of west cameroon: north west regional consultative study for the netherlands development association (snv), yaoundé: snv p. 305. ired (1998a). direct funding from a southern perspective: streng thening civil society. ired forum geneva. 68: 27-29. ired (1998b) ngo good policy and practice: a straining kit. red forum geneva 68: 29. macleod h (1986). the conservation of oku mountain forest, cameroon. icbp, cambridge pp. 1-2. minpat/undp (1999). regional socio-economic study on cameroon: the north west province. minpat/yaounde, pp. 5-27. ndenecho en (2000). appraisal of ngo intervention in natural resource management: tubah upland watershed, helvetas sponsored nrm formative evaluation. 10 th – 17 th january 2000. bamenda: helvetas p. 31. ndenecho en (2003). a landscape ecological study of the bamenda highlands. unpublished ph.d. thesis, university of buea. ndenecho en (2006). sustaining mountain environments and rural livelihoods in bamenda highlands, unique printers, bamenda. pp. 44 -60. stuart sn (1986). conservation of cameroon, mountain forests. report of the icbp cameroon mountain survey: november 1983 – april 1984. icbp, cambridge pp. 7-21. tah h, zimmermann t (1994). report on the evaluation meeting of the bambui watershed project. bamenda: helvetas, p. 5. wiendels m (1993). region north west/west: institutional infrastruc ture. yaoundé: snv. pp. 17-34. zimmermann t (1995a). project proposal for guzang watershed. helvetas, bamenda. p. 5. zimmermann t (1995a). project proposal for mbiame watershed. helvetas, bamenda p. 6. zimmermann t (1994a). project proposal for the conservation of the bambui watershed bamenda: helvetas p. 7. zimmermann t (1994b). project proposal for rehabilitation of bambili, rca bambili, irz bambui watershed project. bamenda: helvetas. p. 5. zimmermann t (1994c). an introduction to watershed management for intake areas of rural water supplies in cameroon. yebit, g. et al. proceedings of agroforestry harmonization workshop, 4-7 may 1994 organised by rca bambili, usaid. zimmermann t (1996). watershed resource management in the western highlands. bamenda, helvetas, p.76. african journal of environmental economics and management vol. 1 (4), pp. 086-096, november, 2013. available online at www.internationalscholarsjournals.org © international scholars journals review role of participatory research on natural resource management: a case of karnali watershed area, nepal kabi prasad pokhrel geography, research division, tu, kirtipur, tribhuvan university, nepal. e-mail: drkabipokhrel@gmail.com tel: +977 9849301741. accepted 21 july, 2013 this paper discusses the development trends of participatory research in nepal with reference to natural resource management, taking example from karnali watershed area. the issues discussed in this paper clearly indicate that there is urgent need to promote the participatory action research on environment and development for the proper links between population, development, technological implication and institutional strengths, using a micro level conservation and development model that suits local environments. the author opines that both government organizations and academic institutions have to join hands with an effort to promote the participatory research culture in karnali watershed area for sustainable natural resource management. key words: scientific research, relaxed rapport, extractive survey, eco-development, integrated conservation and development planning, village level model. introduction over the decades, there have been drastic changes in modes of research and learning. shifts from logicalpositivism paradigms (quantitative) to phenomenological paradigms (qualitative) have been witnessed in research and development practices since 1980s. these shifts move now from top-down to bottom-up and from extractive survey questionnaires to participatory appraisal, in which more and more activities for innovation, management and development of available resources are done by local people rather than outsiders. it is seen that various methods and approaches of participatory research evolved from here, with local people learning these methods themselves in order to map out their conditions in planning and action. an important method of participatory research is rapid rural appraisal (rra), which had a widespread in the 1980s. its further evolution, which was met in the 1990s, into participatory rural appraisal (pra) has grew fast and promoted participatory action research (par), participatory learning action, focus group discussion and perception study for development dialogue with a view to enable local people share, enhance and analyze their knowledge of life and conditions to plan and to act. thus, the participatory research in natural resource management and development appeared since 1990s with several sources, reasons and traditions; however, the term activist participatory research was introduced in the 1970s by the work and inspiration of paulo freire in his book pedagogy of the oppressed (rhoades, 1990; chambers, 1995). historically, it evolves continuously quicker and closer communication, transfers and sharing of activist participatory research, agroecosystem analysis, applied anthropology, field research and rapid rural appraisal. particularly, field research on farming systems and conservation of natural and environmental resources by geographers, agricultural economics or biological scientists have contributed in shaping the present form of the participatory research in a complex structure. location of the karnali watershed area the karnaliwatershed basin (kwb) lies in the western part of the mid western development region of nepal, which is about 500 km west from the capital city, katmandu, of the country. it is located between 27°42' n pokhrel 086 figure 1. map of karnali watershed area. to 30°27' north latitude and 81°e to 83°45' east longitude, extending from dhaulagiri himal in the east to bayas-rishi himal in the west. the total spatial cover of the area is 42,559 sq km, which is about 29.02% of the country. its average length is 176.59 km from the east to west with non-uniform width of 240 km from the north to south (mofsc, 2010). hence, the north-south extension of the basin makes great variations between ecological regions namely: mountain, hill and tarai in regard to relief features, climatic characteristics, and distribution pattern of resources. however, about 80% of the land is covered by rugged terrain. the elevation ranges from 129 m in the southern plain area to 7,000 m height in the northern mountain (cbs, 2007). it borders the western development region in the east, far-western development region in the west, uttar pradesh of india in the south, and the tibetan region of china in the north (figure 1). review of participatory research activities researchers and scientists believe that participatory research is a legitimate and useful method of scientific research in natural and social sciences by rapid assessment procedures like conversation, observation, informal interviews and focus group discussion of realities. chamber (1989) pointed out many reasons to the origin of the rapid rural appraisal that further evolved into participatory rural appraisal and participatory action research. among them, the first reason was dissatisfaction with anti-poverty biases of rural development by urban-based professionals. these biases were spatial (visit to nearby cities, on roadsides, and to the villages’ centers with neglected peripheries), a project that gave special attention to the donor desires rather than people’s demands, a person meeting men more than women, and elites more than the poor and disadvantaged groups, seasonal visits to sites in favorable weather, and diplomacy, that is, where the outsiders do not wish to cause offence by asking to meet poor people in bad conditions. the next one is disillusionment with the normal processes of the questionnaire survey and their results. this is as a result of the fact that the conventional approach to research tended to be long drawn-out, tedious, difficult to administer, a nightmare to process and write up, inaccurate and unreliable data obtained, and difficult to use in wider perspectives. another important preseason was more positive and was in favor of this study to make it a more cost-effective method of learning. it was 087 afr. j. environ. econ. manage. developed by the growing recognition of the development professional to discern the fact that rural people are knowledgeable on many issues which touched their lives and which are recognized as the indigenous technical knowledge (itk) to tap it more effectively, as a source of information for analysis and use by outsiders. in the mid of the 1990s, it became a more popular model of research and development in asia, africa and south america in both the gos and ngos sectors. it also became the main theme of field research for academic institutions and it spread internationally. many international ngos contributed to shape its present form, which is important for need based development activities. among them, international institute for environment and development (iied) london, institute of development studies (ids) uk, world bank, action aid and win rock international have played significant role to promote the participatory research. therefore, it is a simple method, with set of approaches for scientific inquiry that enable local people conduct their own analysis and often plan and take action. principles of participatory research to carry out a good and practicable participatory research, some important performances are required by the practitioners, and they are briefly discussed here. a reversal of learning: to learn from rural people directly, on site and face-to-face, thereby gaining from local physical, technical and social knowledge. learning rapidly and progressively: with conscious exploration, the flexible use of the methods of opportunism, improvisation, iteration and cross checking do not follow a blueprint program, but the ability to adapt in any learning process. offsetting biases: rural development is all about relaxing and not rushing, listening and not lecturing, probing instead of passing on to the next issues, being unimposing instead of important, and seeking out the deprived people and learning their concerns and priorities. optimizing trade-off: relating the cost of learning to the useful truth of information, with trade-off between quantity, relevance, accuracy and timeliness. this includes the principles of optimal ignorance knowing what is not worth knowing, and of appropriate imprecision not measuring more than needed. as keynes is reputed to have said; it is better to be approximately right than to be precisely wrong. triangulating: using a range of methods, types of information, investigators and disciplines to cross-check. seeking diversity: this has been expressed in terms of seeking variability rather than average and has been described as the principle of maximum diversity or maximizing the diversity and richness of information. this can involve sampling in a non-statistical sense. it goes beyond the cross checking of triangulation. defined broadly, it deliberately looks for notices and investigates contradictions, anomalies and differences. facilitating: rural people are allowed to facilitate investigation, analysis, presentation and learning by themselves, so that they present and own the outcomes, and as well learn from it. this has been expressed as ‘handing over the stick’. this often entails an outsider starting a process and then sitting back or walking away, and not interviewing or interrupting. self-critical awareness and responsibility: facilitators continuously examine their behavior, and try to do better. this includes embracing error-welcoming error as an opportunity to learn to do better and using one’s own best judgment at all times, that is, accepting personal responsibility rather than vesting it in a manual or a rigid set of rules. all these principles are behavioral, since they are applied in practice by people doing things. thus, the quality and accuracy of participatory research in environment and development area depend on the moral responsibility and technical efficiency of researchers. in the new millennium, it is more applicable in integrated conservation and development planning with respect to climate change adaptation and humanitarian issues. thus, it requires picking up an appropriate theme and area of research that has in the priority of the country issues that suite the interdisciplinary research. however, funding institutions do not provide grants to such research in general due to the tradition of providing grant based on donor desires rather than local needs and demands. it further demands that the old concept of research and fund granting traditions should be modified to make it more applicable for use in research outputs into socio-economic development with due consideration of natural resources conservation and development policies of the country, which could be carried out with indepth investigation, critical inquiry and exact assessment in seeking facts through collective efforts. conducting such research in an environment with natural resource appraisal and development, self searching methods of inquiry that promote the culture of self-research with participatory mapping and modeling of what is on ground are used. it also requires that trend analysis, livelihood analysis, analysis of difference and participatory planning and budgeting should be done. innovation of participatory research participatory research has broken new ground of research pokhrel 088 and methods of rediscoveries that encourage people to improvise the spirit of play. various discoveries and innovations of participatory research have existed since the last three decades, and are briefly reviewed. villagers’ knowledge and capabilities: the first discovery is that villagers have a greater capacity to map, model, estimate, rank and score their surrounding resources than outsiders. findings of the participatory research show that rural people have more extensive and detailed mental maps than urban people and that when given the right conditions and materials, they can express this visibly on ground or on paper as three dimensional models (that is, watersheds). rural people have now noticed social details using local materials such as seeds, manure, vegetables; land resource, water resource, market and other information. it evinces that having the right methods and materials, villagers can show themselves capable of generating and analyzing information far beyond normal professional expectations. it is evident that rural people are able to use largely independent culture of literacy to reflect and rank the problems and opportunities as they perceive them, and express their preferences for improving their farming system, managing and using common property resources for better livelihoods and for development actions in their communities. relaxed rapport: the second discovery (the relaxed rapport between outsiders and rural people) can be established early in the process, which is the key to facilitating participation. to measure trust and minimize predisposing conditions for inquiry, it promotes the culture of honest and accurate sharing of detailed knowledge and values between outsiders and villagers. diagramming and visual sharing: the discovery is the power of diagramming and visual sharing information. it helps to transfer the world of the person interviewed into paper and to change the information into public goods from personal to unverified. with visual sharing of map, the model, diagram or unit can be used for ranking, scoring, counting, or quantification, and all who are present can see, point, discuss, manipulate and alter physical objects or representation. triangulation takes place with people crosschecking and correcting each other. learning becomes more progressive and information is visible by the public, checked, verified, amended, added to and owned by the participants. through participatory mapping and modeling, villagers can draw and model their resources with location, deciding what to include, debate, add and modify in the details. in shared diagramming information, seasonal changes dimensions, such as rainfall, agricultural production, labor, income, indebtedness, food security and migration trends can be shown in paper or other local materials. in the media, villagers commend and alter the fact of whether they are literate or not with confidence. sequences: the next popular discovery is the sequences of participatory methods like participatory mapping, social mapping and matrix scoring or ranking, which have more striking combinations and sequences that present new and complementary information on socio-cultural, natural resources and livelihood improvement aspects. in many areas, participatory resource map leads to transect planning, in which villagers made the map act as guides for outsiders. it further leads to the identification and discussion of problems and opportunities and then leads to listing and ranking options. a village social map provides up-to-date household information which leads to discussion, negotiation and reconciliation of priorities. thus, the power of such sequences is four fold. first, the commitment of participation increases, before it further makes the action more likely, spontaneous and sustainable. secondly, sequences triangulate and reveal errors of omissions in earlier presentations. thirdly, the different activities interact cumulatively, and each activity add a dimension to the quality of details and enrich others, so that when taken together the whole become more than the sum of the parts. fourthly, all concerned learn through the process, through people sharing what they know, through observation and through analysis. therefore, participatory methods fit well with flexible learning process approach which is even more openended and adaptable to the villagers. thus, it enables them use their own categories and criteria to generate their own agenda, and to assess and indicate their own priorities. training and reorientation for outsiders: the fifth innovation of participatory mapping, which is the initial training and orientation given to outsiders, can be conducted in practice in a short span of time. face-toface field experience is the main thrust of participatory research. hence, the principles of optimal unpreparedness are applied. usually, it is best to start sooner; as such, it seems safe or sensible for newcomers not to wait, but to start, stumble, self-correct and then share. through participatory methods, villagers are encouraged to map, participate and plan for the training of outsiders to facilitate changes in perceptions and action, listening and not lecturing, learning progressively, embracing error and being critically self-aware of participation. thus, the reversing role is taught to villagers in order for them to perform village tasks. for some outsiders, especially those who have had a strictly formal professional training, this can threaten trauma. they deserve sympathetic understanding, and no significant change may take place. for some though, a new range of possibilities and sense of freedom to experiment and innovation opens up. thus, there is no need for the villagers to be trained in all methods. the methods can be tried, improvised and adopted subsequently, and new ones can be invented. 089 afr. j. environ. econ. manage. sharing and spread: the last and most important discovery is sharing the culture and spread of technologies through participatory research. participatory research is recognized now to have three foundations: methods, behavior and attitudes, and sharing. previously, methods appeared to be the most important than behavior and attitudes of the outsiders, but now sharing is the most important for spreading of experience and mutual learning. to share and exchange methods and experience, interchanges of staff are efficient; as such, staff of one organization spending time with staff of other organizations can enhance the creativity and inventiveness of villagers to come into play. in such ways, innovations can be continuously stimulated. thus, all forms of sharing-trainings, trainers, ideas, experiences, methods and innovations take place. practical application of participatory research participatory research methods, approaches and techniques have been widely used for appraisal, analysis and research in many subject areas such as agro ecosystems, natural resources, environment, technology and innovation, health and nutrition, family system research and extension, pastoralism marketing, disaster risk reduction, organizational assessment, socio-cultural and economic conditions. participatory appraisal and planning, participatory implementation, monitoring and evaluation, and training and orientation for outsiders and villagers are the major processes that have been used in development and resource management areas. however, most of the application of the participatory research can be listed out in four categories. natural resources management: participatory research is more popular and it uses widely acceptable techniques for watershed planning and management including: rapid catchment assessment, soil and water conservation, degraded forest assessment, nurseries and planting, identification of trees’ uses, rural energy assessment, green enterprise development, wildlife reservation, and village resource management plans. agriculture: the next application is farmer participatory farming system research done by farmers in addressing crop farming, livestock farming, irrigation system, and market network for their products. equity and inclusive development: another application focuses on a research on policy level to sustain the growth momentum in order to ensure inclusive development, where benefits of economic development are to percolate to the poor and under privileged with an objective to boot economic growth along with augmenting employment opportunities, alleviating poverty and ensuring regional equity and prosperity. health and nutrition: health and nutrition monitoring is the fourth important application of participatory research which focuses on reproductive health, disease problem ranking, healthcare providers and costs, planning health projects, food security, nutrition assessment and monitoring, and water and sanitation assessment, planning and location. all these applications are positive evidences that are scaled and used by various organizations and individuals, who have been engaged in training and appraisal, to respond to demand and their own sense of priorities and experiences. the use of monitoring and evaluation was found to be limited and academic researchers have been slow to recognize what was happening in practical application of participatory research. these methods have usually proved more reliable in information flow arguments and discussions taking place among the villagers, outsiders and between both villagers and outsiders. however, the success and failure much depend on the behaviors and attitudes of the outsiders whether or not they have the time, patience and will to get closer to reality. any way, reversals of modes like from closed to open, from verbal to visual, from counting to comparing, and reversals of dominance as from extracting to empowering, reserve to rapport and from tedium to fun are some important changes in the research that was brought out by participatory research. in nepal and other developing countries, like india and the middle east countries, it proved more useful to carry out the research and development activities for conservation of environmental and natural resources and livelihood improvement of rural communities. besides these, policy research and change, personal behavior, attitudes and learning, farming system research, quality assurance, inclusive growth and empowerment, and substituting for survey are potential fields to participatory research in nepal for achieving flexibility by empowering people, learning to love change, becoming obsessed with listening, deferring to the front line, and building system for a world turned upside down. therefore, we have challenged the locals to further develop and disseminate approaches and methods to promote their own analysis and make their own needs and priorities known to scientists. usage of participatory methods in karnali watershed area since 1990s, participatory approaches and methods of research and development have been widely used in many parts of the country. particularly, this has been done in rural resources development and management practices through community based organizations and users’ groups at community level, and it has become more popular in the world as the model of participatory development, such as community forestry and water pokhrel 090 table 1. perceived challenges for ensuring people’s participation. challenges key informants no. % lack of ownership feeling 12 19.57 low level of public awareness 9 14.28 unclear policy 7 11.11 growing unemployment 9 14.28 lack of technical assistance 7 11.11 lack of social mobilization 7 11.11 lack of need basis plan 11 17.46 total 63 100 source: field survey (2010). resource management through users’ groups. many gainful evidences indicate that rural communities have benefited from using participatory methods to development for improving their farming system, conserving their available resources and preparing their own plan based on their own choices. however, it has little effects in karnali watershed area. there are many reasons behind this which are discussed here with resolutions in brief. low level of people’s participation the onward fifth five year plan (1975 to 1980) was initiated with the central objective of institutionalization of people’s initiative in all development plans. the decentralization act of 1982 was enacted in the mid 1980s. however, in practice, particularly, in the karnali watershed area, it is often seen that both the government and nongovernmental organizations, involved in the local resource development, did not promote people’s participation, rather the local people were kept away from taking active part in development. in the most cases, local people had not been given the choice to take decision for their development. even though the financial authority was kept by the central government, the role of government was still found as the body in-charge of development and welfare of the local people. further, there is growing number of middlemen who have bred corruption and mismanagement of available resources. thus, only a small number of elite people are the beneficiaries of the development activities. the local people (real beneficiaries) are always kept far from the mainstream of development. it is evinced that the drawbacks of top-down development approach have largely been attributed to promote the people’s participation in local level development. sundaram (1997) has nicely noted that the government mechanism in asian countries, like nepal and india, hardly want to enhance the people’s participation in the real term. it may be seen from table 1 that the unclear government policy towards the participatory development, owing to the lack of strong sense of ownership feeling of local people on the ongoing development programs, was observed as the main challenges for increasing people’s participation in the area. the skewed distribution of resources has also been hampering people’s participation and the major bulk of resources are to be occupied by a small number of elites. about 11% of key informants have noticed the lack of appropriate social mobilization policies where people are educated, organized, motivated and enabled to undertake social enquiry and analysis for understanding their life situation and taking decisions and actions to change it for their well-being. as a result, 14% of the key informants further noted the dominant role of resource rich family on community-based organizations, which is further responsible for mass unemployment, and low level of local participation. moreover, people’s involvement has been considered to volunteer a form in the implementation stage of local development in the region. thus, it is the central government authority that takes almost all development decisions. consequently, the local needs have not been taken seriously at the time of programming. all these make the people to be less willing to participate in development activities in karnali watershed area. among the various issues, the most remarkable was observed to be technological drawbacks. the present use of technology for local resource mobilization is not appropriate and adequate. the level of participation has also been observed to vary among the ethnic groups based on resource base and priorities. therefore, an appropriate need-based and time specific strategic intervention in various stages is of utmost importance for the mobilization of local resources. on the whole, the imposition development from the top level without due consultancy from the village level failed to activate people’s participation in local resource mobilization. so, there is a need to look at the opinion and idea of the local people in utilizing the local resources effectively at the local level. it shows that people’s participation is found as the most effective social measure for empowerment of local communities and the only way by which backwardness of the area can be eradicated (pokhrel, 2004). it further permits to note that genuine public participation of people at the centre of development is the hallmark of eco-development. this is so, because it is an endogenous development process in which local people themselves assume the responsibility to manage their resources, define their needs, goals and aspiration, and to make decision affecting their well being and sustainable development. people’s participation is the process by which the rural poor would be able to identify their needs, share in design, implementation and evaluation of the participatory action for resource development (fao, 1990). some important activities that have been conducted by local communities for the conservation and management of natural and livelihood resources in karnali watershed area are presented in the following photographs (figures 1, 2a, 2b, 2c and 2d). figure 2a. briefing of project activities with authors at the field office of the local ngo. figure 2d. discussion with beneficiary women of organic farming. figure 2b. meeting with beneficiary farmers of jumla. figure 2c. discussion with inrm user groups in surkhet valley. under such circumstances, the collective efforts of locals become self -organizing and self-sustaining in unleashing the potential of the local community and in meeting their inner urges and preferences with regard to development through self-reliance. the gravity of such development is to be self -generated, selforganized and self-sustained at the local level (gultung, 1980; charles, 1987; bajpai, 1998). thus, the insight development of the locals is most important. in doing so, there is an immediate need of resource knowledge to the local people which is further possible through people’s resource right (joshi, 2002). of course, to ensure people’s involvement in ecodevelopment activities of the concerned communities, they must have a sense of belonging to the local and natural resources that is the main process of gaining power by real actors. therefore, efforts are needed to promote the capabilities of local and indigenous institutions for making their functions more productive. this is possible only by strengthening such community institutions through providing sufficient autonomy as part of the organization involved in resource development. so, if local communities are to become principal actors in promoting their social well-being, they must be able to give vision and focus to their endeavors. it is indicative that devolution of power from the top to bottom (that is, grassroots) for capacity building with generation, application and diffusion of knowledge through a unified approach social change at the grassroots level could be achieved, and the resource poor could participate directly in efforts to improve their own well being. furthermore, their participation must be substantive and creative in order to enhance the development of material resources and technologies with regard to serving and matching its real needs. it is clear that ecodevelopment can only change the potential beneficiaries into functional groups. thus, government authority should be given a priority for ushering in people’s involvement. moreover, it needs to be a strong support of finance, policy and technical inputs from the government to local institutions for enabling their capacity with regard to resource mobilization. most importantly, government authorities need to establish broad eco-technological strategies in partnership with key stakeholders. evidences suggest that in the national 091 afr. j. environ. econ. manage. pokhrel 092 table 2. need of people’s participation for eco-development. perceived needs key informants no. % need basis/bottom up planning 19 30.15 ownership feeling 10 15.87 coordination between outsider and insiders 6 9.52 verification of implementing program 5 7.93 development of indigenous knowledge 6 9.52 organized/collective efforts 8 12.60 institutionalization 9 14.28 total 63 100 source: field survey (2010). level, local resources user groups and self-managed enterprises are emerging and functioning successfully. it proves that such grassroots organizations have great potential in those regions like the karnali watershed area where environmental, as well as development challenges are immense. for this purpose, local people (that is, primary beneficiaries) need to form their own organization different from that of the primary local unit for mobilizing resources to acquire ownership of resource utilization and management overtime and assume full responsibility on decision making and implementation of community based resource development activities (bavuskar, 1999; sethi, 2003; world bank, 2003). to achieve this, first, efforts need to be made to access the attitudes, behaviors and priorities of the locals with deep understanding of the group dynamics and heterogeneous characters of the society. secondly, steps should be taken to identify and support formal and informal groups and institution. so, special attention must be given to explore the resource and resource rights. it is necessary thus to ensure ecoeducation of people to make them able to understand their needs and problems. thirdly, investment has to be made in institutional capacity development which will further enhance the internal capabilities of local units. such institutions should be considered as the form of public services. therefore, local authorities must be strengthened to secure common benefits through accepting mutual obligation on resource mobilization. it shows that people’s involvement in resource development is necessarily desirable for a need base bottom-up planning, strong feeling of ownership on local resources, development of indigenous technology and promotion of collective action of the grassroots people in the region. it can further be noted that coordination among and between the line agencies who are involved in community based resource development, correction and verification of their implementation procedures, and institutionalization of such community based organization are also possible at the micro level by adopting eco-development strategy (table 2). thus, people’s participation is essential to replace a relationship based on dominance and competition with that based on reciprocity and collaboration, and to promote solidarity and unity of purpose among all members of the community. however, several challenges are ahead in ensuring people’s participation in the study region. in most cases, the mechanisms involved for this purpose have failed to reach the grassroots level. the possible reasons might be over dependence on foreign aid and central controlled programs. therefore, need base and resource base planning with right advocacy skill development and technical dissemination should be emphasized on government policy. at the moment, local efforts should be institutionalized to empower themselves with regard to income generation, social change, environment management and ecological balance of community life in the region. emphasis should also be given to human resource development in order to promote the indigenous resource management system. such indigenous systems have significant role on conservation of forest and other natural resources. for example, community forest user groups have proved themselves to be more responsible and reliable than the government officials. so, the participation of user groups and others who have rights in decision-making process about utilization and conservation of local and natural resources is what is needed now with respect to the region’s sustainable development. therefore, cultural, social and ecological dimensions should be prioritized in the implication process of integrated eco-development strategies in karnali watershed area, because the gravity of cultural values, social norms and people’s perception is much more on the control mechanism that acts for resource utilization and management. in short, the current emphasis should be on policies for strengthening indigenous resource management systems and institutionalizing such systems in order to succeed in the integrated eco-development model at the village level. eco-development practices it is true that in karnali region, the traditional farming system might have some little effect on ecological stability, so long as the population of man and his animals do not exceed the carrying capacity of the environment, but when they do, there has been consequent pressure on land, less suitable for farming, depletion of forest resources, erosion, and environmental destruction particularly of the marginal and sensitive areas. lack of ecological consideration in development activities has also been intensified by environmental assaults and the life support systems have undergone diminishment. thus, there is need to modify current land use policies that can make the region available for ecologically sound and sustainable agro-farming with man-environment kinship needs to be restored in order to link the socio-economic interests of the local people with the sustainable management of natural resources for environmental stability and ecological security. therefore, shift in priorities, change in implementation methods, modification in the planning process, and examination in resource allocation patterns are needed for maximizing the economic returns of development without ecological destruction. due to the wide range of topography, climatic elements, soil characteristics, and socio-economic condition, the karnali watershed area presents very special ecological features having more than 75% of terrain rugged and steep, and the unit cost of infrastructure development is high, while returns are relatively low. the ever growing human demands, faulty method of cultivation, and development patterns have brought considerable damage to fragile eco-systems in the area. in this regard, an integrated approach of development and conservation by involving local people in all processes and steppes could be effective to promote the quality of life of the people in the area, because eco-development refers to sustainable development in which all development activities are performed in such a way that regional ecological balance can be maintained. practically, environmental planning is done for regional (meso) and rural (micro) level development with a rational use of the resources and application of technological styles (bhati, 1985; guleria, 1987; peet, 1989). through the principal objectives of the development strategies, protection of the available resources, regeneration of resources and development of human knowledge could enhance the quality of environment and the economy of the area. furthermore, through social development with respect to maximizing the productivity of both the natural and human resources, and through preventive planning and development policy, many adverse ecological consequences could be avoided and the interest of the local people to environment management could be enhanced. finally, people will feel comfortable with their environment and process of development. therefore, such development approach would make people adopt the integrated conservation and development in which people can decide their real goals and objectives for the proper utilization of local and natural resources. at present, it is shaping into people’s movement, and the active people’s participation is envisaged from the grassroots rather than from the remote control exercised by the corporate executives. consequently, a fair hope that people can decide what their priorities of work are for conservation and development is expected. thus, it is necessary to give top priority to the livelihood of the locals for designing such development strategies. this can be achieved through social planning norms that promote an organized collective effort of local people at the community level. all these are possible on a resourcebase planning unit which may be a watershed unit, be it macro or micro, but more than the political boundary. it also enables the integration of environment management and socio-economic development by adopting watershed management approach at the village level. it shows that the holistic vision of the proposed development strategy is essential for the integration of the environment into development practice with regards to rational utilization of local resources and minimization of the environmental hazards. watershed management it is clear that the plans of the administrative units and central government failed to address the real needs of the area and the utilization of regional resources in karnali watershed area. this is mainly due to topdown planning for local development and less interest of local people towards the government launched program. further selection of the planning unit which is based on political boundary is also the factor responsible for ignoring the ecological bases of development. thus, a socially desirable, economically viable and ecologically sound development approach is required to promote harmonious relationship between development and ecology. it is possible, to adopt only the watershed management strategy that prove to be an appropriate development path for the area. pokhrel (2009) has noted that watershed management strategy should be the core for development activities, and there is need to popularize it in himalayan region. some other case studies have also shown that the integrated watershed development approach is more practicable and it evolves a compact technical, economical, ecological and geographical unit of planning for resource utilization and conservation (goi, 1988; grewel et al., 2001; narayan, 1993). thus, in karnali watershed area, watershed management approach could play a significant role in increasing the productivity of the total resources. watershed is a very appropriate spatial unit for examining the physical aspects of karnali and its tributary rivers with 093 afr. j. environ. econ. manage. pokhrel 094 table 3. number and area of watersheds. catchment watersheds sub watersheds micro watersheds basins area (km 2 ) per area (km 2 ) no. no. area (km 2 ) no. area (km 2 ) watershed karnali 42,890 7 6,127 15 2,859 90 476.55 babai 3,270 2 1,635 6 545 27 121.11 rapti 6,500 5 1,300 10 1,083 42 240.71 total 43,260 14 3,090 31 1,395 159 272 source: sharma (1977); field survey (2010). their size, which may vary from small to some large catchment areas. so, watershed is a logical planning unit for evaluating the biophysical linkages of upstream and downstream activities of the basin. it is only the sixth fiveyear plan introduced as an integrated development approach in nepal as the synonymous of soil and water conservation, but the failure of large scale development programs and the realization of the importance of interlink ages between resource productivity and sustained increase in rural income have led to the shift in watershed management approach with the prime focus of integrating environment and development in regional level. in operational level, it made efforts to bring all concerned institutions into single window system through interdisciplinary approach. recently, it is more anthropoeco-centric and community based rather than technology based, thereby leading empowerment and self-reliance of the primary stakeholders as an entry point for outsiders to understand local environment, and for making development plan in a comprehensive way. however, evidences show that macro watershed management programs in nepal have some remarkable failures, in that many watersheds are still being degraded. particularly, in the karnali watershed area, large scale programs have rarely been successful in conservation and utilization of local and natural resources with people’s participation. the degraded watersheds are further worsening due to over intervention of outside technical teams (shah, 2000). thus, social mobilization is needed to enhance the success of watershed development approach for the strong feeling of belongingness of local people towards the ongoing development and conservation programs. this is possible only by adopting micro-watershed development approach that can provide an appropriate path way for eco-development. further, it would also be helpful in devising location specific solutions that may emerge by resolving activities that are conflicting (head reach-tail end beneficiaries), and build-on complementary activities (forestation and soil conservation in hill and mountain regions enables better productivity in the tarai region). thus, emphasis should be shifted from large to small watershed areas in which both management of environment and socio-economic development can be integrated (agarwal, 2003). therefore, an effort is made here to delineate estimated watersheds, sub watersheds, and micro watersheds in the region. based on the drainage pattern, transport network, population statistics and relief features, the whole karnali-west rapti basin (43,260 km 2 ) was divided into four hierarchical orders: resource regions, macro watersheds, sub watersheds and micro watershed. so, 14 macro watersheds, 31 sub watersheds and 159 micro watersheds were identified as the unit of eco-development planning in the area (table 3). these micro watershed units can further be subdivided into small and mini watershed units varying in size (50 km 2 ) for different land use purposes. therefore, it is the micro watershed development strategy that could solve the problem of the five ‘es’: employment, economy, ecology, expert and equity, and would then be ushered in eco-development with a sharp focus on resource conservation and poverty alleviation in the region. furthermore, the institutional and technical co-ordination amongst the involved agencies would also be strengthened in the region (figure 3). as the concept of integrated eco-development refers to sustainable resource development, it requires local initiations for integrating the environmental issues into socio-economic development. this development approach can make a substantial contribution to resource management at the micro level incorporating biophysical, technological, social, political and other variables which account for resource utilization and conservation. further, such type of development approach maps the complex connection, direct-indirect effects, feedback loops, and reciprocal relations and effects of environmental and human resources to each other. experiences have shown that local institutions in essence, community resource user groups are so effective in conservation and development of natural resources at regional and national levels in the country. even in many parts of the karnali watershed area, especially in the hills, such user groups have also exhibited extra-talents in forest resource protection, utilization and management. thus, it is strongly felt that a micro level resource utilization and conservation model is necessary in the precise and synthetic form that would increase the productivity of environmental resources in a sustainable manner. such grassroots model can as an aspect of bottom-up strategy call for mass action at the micro level (that is, village level). so, the kingpin of the natural resource pokhrel 247 figure 3. watershed management in karnali watershed area. development strategy of karnali watershed area is selfreliance on resource mobilization by using indigenous knowledge and experiences. thus, the right mix of traditional knowledge would be a winning combination of resource development. the central thrust of participatory development has to integrate development and conservation, government authorities and local beneficiaries, and coordination of the involved institutions between the decision making and implementation level and that of the micro watershed level. further, such adaptive model of resource management focuses on environmental feedback to shape policy. thus, the model explicitly considers social learning and institutional development. under such provision, large numbers of community based organizations would have evolved out of the region, and would be able to develop locally suitable technology, appropriate policy feedback and strategic clarity for resource development and conservation. better information system, participatory monitoring and systematic implementation of resource mobilization will also evolve through local initiations. finally, a specific technique would be modeled against the top-down tendencies for resource based regional development planning in karnali watershed area and in nepal in general. for this purpose, it is necessary to build-up local capacity for the total reforms of institutions in order to change the environmental policies in different orders. the principal concepts and components of this grassroots development model are: (i) formulating policy, strategy and programming the project based on the resource knowledge of the local people and an application of a suitable technology. thus, it has to have a local base including people, traditions and indigenous institutions. (ii) implementation of resource development activities through people’s involvement to strengthen local organizations and to bring about positive change in the local environment. (iii) participatory monitoring system with a view to avoid previous drawbacks of resource development planning at the micro level. thus, such innovative model can eventually lead to a district, as well as village level conservation and development plans. further, such model could successively imply that the local organizations have to control the local and natural resources, adopt a sustainable pattern of development and avail appropriate technologies in subsequently distributing local resources 095 afr. j. environ. econ. manage. pokhrel 096 amongst beneficiaries on an equitable basis. therefore, government authorities need to develop suitable methodology and guideline in order to ensure people’s participation and facilitate local organizations for the process of institutionalization in the proper way. similarly, to provide some financial support in the form of seed money is also needed. to build up local capabilities by imparting training and techniques at the local level is also essential from the government side. hence, it should be emphasized that the catalytic role of government is to galvanize the people to initiate resource development actions according to their priorities at self reliance. in this regard, district development committee (ddc) and village development committee (vdc) as the authority of government need to make a framework, in which this model may function and evolve. to achieve this, there is need to modify outside intervention for the dynamics of local institutions. actors, like non-government organizations, should collaborate with resource owned communities to develop the integrated micro level model, and explore and exhibit relevant alternatives that would stimulate the development of new resource management institutions (saravanan, 2001). conclusion it is evident that such participatory resource-based research and development model enables both the local people and collaborating authorities to learn about each other (their goals, knowledge and techniques) and finally make development efforts that are socially desirable and ecologically suitable. all these imply far-reaching changes and cooperation among and between the beneficiaries with respect to up-grading of skills and adaptation of new technologies for community based resource utilization and management in karnali watershed area. references agarwal sk (2003). integrated watershed development: technology based model for rural development, kurukshetra. 51(12): 49-57. bajpai pk (1998). people’s participation in development: a critical analysis, in s.p. srivastava (ed).the development debate: critical perspectives. rawat publishers, jaipur. baviskar a (1999). participating in eco-development: the case of the great himalayan national park. in jeffery r, sundar n (eds.). a new moral economy for india’s forests? discourses of community participation, sage publication, new delhi. bhati jp, swarup r (1985). why eco-development planning fails in the himalayas: some 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integrated watershed development for hill regions, rain fed farming system, government of india, vigyan bhawan, n delhi. grewel as, jai tc (2001). poverty alleviation and resource conservation through integrated watershed management in a fragile foot-hill ecosystem. in stott de,. mohtar rh, steinhardit gc (eds) sustaining the global farm. usda-ars national soil erosion research laboratory, purdue. guleria as (1987). a strategy for eco-development in himalayan region: watershed approach in pangtey yps (ed) western himalaya: environment, problems and development, gyanodaya prakashan, nainital. joshi ap (2002). resource rights – community domain, kurukshetra, 50(7): 12-14. narayan vd (1993). watershed management: concept and framework in soil and water conservation research, indian council of agricultural research, new delhi. peet r (1989). new models of environment and resources. in peet r, thrift n (ed) new models in geography, unwin hyman ltd., london. pokhrel kp (2009b). climate 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farmer first-rural people’s knowledge, agricultural research and extension practice, intermediate technology publications ltd., london. sundaram kv (1997). development from within: rethinking on an alternative development path, in george kk, nair vs, jacob j (ed.) economics development and the quest for alternatives, concept publishing company, new delhi. world bank (2003). world development report, sustainable development in a dynamic world, transforming institutions, growth, and quality of life, the world bank and oxford university press, new york. in ternationa l scholars journa ls african journal of environmental economics and management issn 2375-0707 vol. 5 (6), pp. 341-347, november, 2017. available online at www.internationalscholarsjournals.org © international scholars journals author(s) retain the copyright of this article. full length research paper willingness to pay (wtp) for pipe-water connection in makululu compound of kabwe, zambia yordanos gebremeskel1, nyambe mubita2, bupe simuchimba1, james mulenga1 1 mulungushi university. school of social sciences. department of economics. box 80415. 2 university of barotseland. school of natural resources. accepted 05 october, 2017 the availability of safe drinking water is dependent on better and improved water sources for households. access to safe drinking water especially piped water is one of the challenges faced by households in zambia. this study aims to understand the factors that determine the willingness to pay for pipe water connection on low income peri-urban settlements in zambia. double bounded questions which have the advantage of including a follow up dichotomous question after the first dichotomous choice question are used. an interval regression model is used to analyze the collected data. the variables of interest are purification, family size, water quality, education and income. the results obtained show that most of these variables have the expected signs. further, the results suggests that an increase in income will lead to an increase in the willingness to pay to have access to safe drinking water sources. the results also suggest that the distance travelled to fetch water from a community tap and level of household education play a role in the willingness to pay for access to pipe water connection. we estimated that the sample household mean wtp is k283.77 ($38.14) which is roughly 33% of the commercial connection charge. keywords: contingent valuation, double-bounded, interval regression, wtp, zambia. introduction water is essential for human survival. it is for this reason that in 2010, the united nations general assembly declared safe and clean drinking water and sanitation a human right essential to the full enjoyment of life and all other human rights (unicef, 2014). notwithstanding its importance, access to improved water still remains a challenge to access safe drinking water. as a result, most people continue to be exposed to waterborne diseases such as cholera, diarrhoea, dysentery, typhoid fever among others. according to the world health organisation (who), water borne diseases are among the major causes of morbidity and mortality in most developing countries particularly among children under five years old. contaminated drinking water is estimated to cause 502, 000 diarrhoea death each year (who, 2016). corresponding author e-mail: yorsink@yahoo.com; yordanosge@gmail.com zambia has made progress in increasing access to improved drinking water. the proportion of the population with access to an improved source of drinking water increased from 24 percent in 2007 to 65 percent in 2014 (zdhs, 2015). table 1 below shows that, the percentage of total population piped into dwelling/yard/plot stands at 16 percent in 2014. the progress has been necessitated by the various programmes that the government together with its cooperating partners have implemented such as the national rural water supply and sanitation program (nrwssp) and national urban water supply and sanitation program (nuwssp). despite this progress, access to improved drinking water in general and piped water in particular continues to be a challenge in zambia. in comparison to its neighbouring countries, as is shown in table 2 (annex), zambia has among the lowest levels of access to drinking water. the health and time saving benefits of access to clean water, as private or communal, by households in developing gebremeskel et al. 342 countries have been widely documented. our main objective in this study is to assess their willingness to pay for private pipe-water connection. this is because of the fact that households in our study site already had access to clean water from communal taps supplied by the water utility company. thus study sought to estimate willingness to pay for improved water supply through pipe water connection in bwacha constituency, kabwe, and to determine the factors (variables) that influence households’ wtp for improved water supply. makululu is an unplanned settlement characterised by lack of social amenities such as piped water among others. the contingent valuation method (cvm) is used to estimate monetary measure of preference by directly asking respondents’ willingness to pay for changes in quantity or quality of a good or service ((haab & mcconnell, 2002)). the dichotomous choice contingent valuation method (dc–cvm) can be presented in different forms. the single bounded dc–cvm asks respondents for a predetermined bid amount for their vote or rejection. alternatively in double bounded format we offer a follow-up price (bid) for the respondent after getting a response for the initial bid. the follow-up bid in double bounded take a higher value if the respondent’s answer for the first bid was yes and a lower value if the answer was no. estimation of household’s demand for water usually conducted by capturing key indicators of household characteristics. nauges and whittington (2010) well documented the various empirical researches made on water demand in various countries. recent notable studies in african countries, using various methodologies, have established that income, family size, time spent to fetch water from existing sources, level of education, age of respondent, bid value, perceived quality of current water supply are the main factors influencing households wtp for improved water supply services (gulyani et al. 2005; tarfasa and brouwer, 2013, 2015; genius et al 2008.) despite the fact that various studies have been undertaken to determine the willingness to pay and the factors that determine the willingness to pay (wtp) for quality water in developing countries around the world, we didn’t find enough literature relating to wtp for improved water in zambia particularly employing the cvm. one particular study done in the north western province of zambia by aymar (2004) using descriptive analysis concluded that willingness to pay depends to a large extent on income level. the higher the income, the higher willingness to pay. the paper proceeds as follows. in the next section we present the model of willingness to pay. section 3 discusses study site and sampling technique. sections 4, 5 and 6 are for results, discussion and conclusion respectively. methodology willingness to pay model an application of a contingent valuation questionnaire using the dichotomous choice model renders two answers. these are dichotomous answer ( if the individual answers yes and if the answer is no) given a question about paying a predetermined amount of . the wtp can be estimated by modelling as the following linear function: (1) where is a vector of explanatory variables, is a vector of parameters to be estimated and is the error term. the respondent will answer yes when his wtp is greater than the suggested amount that is when . wtp and double-bounded contingent valuation we can assume that an individual is asked if he is willing to pay an amount for a given change in the provision of a given good or service. if the individual answers no then we can infer that , if he answers yes then . but hanemann et al. (1991) suggested that the follow-up dichotomous question can be asked after the first dichotomous question. this approach, called doublebounded models, is assumed to generate more efficient estimation than a single question or a single question followed by an open ended question. in the case of double bounded model, a follow-up dichotomous question is asked after the first dichotomous choice question. if the individual answers yes to the first question then he/she is asked about his wtp for a higher amount. if he answers no to the first question then a lower amount is offered. the second questions is endogenous in the sense that the amount asked depends on the answer obtained for the first question which is exogenous. the method renders with two answers for each respondent. if we call the first bid amount and the second one , where then i. the individual that answers yes to the first question and no to the second, then . this implies . ii. if the answers are yes for both questions, then . iii. if the individual’s answer are no to the first question and yes to the second, then . iv. finally, if the individual’s responses are no for both questions, then we will have econometric estimation of double-bounded or interval data model let’s define and as the dichotomous variables that capture the response to the first and second closed questions, then the probability that an individual answers yes to the first question and no to the second can be 343 afr. j. environ. econ. manage. table 1. use of drinking water sources (percentage of population) as of 2015: selected countries. country urban rural total total improved piped on premises total improved piped on premises total improved piped on premises botswana 99 96 92 45 96 74 south africa 100 92 81 38 93 73 namibia 98 69 85 34 91 51 malawi 96 33 89 3 90 8 zimbabwe 97 74 67 5 77 28 swaziland 94 75 69 27 74 37 zambia 86 36 51 2 65 16 congo, dem. rep. 81 17 31 1 52 8 mozambique 81 25 37 1 51 9 source: unicef and who, 2015. table 2. socio-economic characteristics of surveyed households. variable name description frequency percent gender gender of the respondent female 63 42 male 87 58 education educational level of the respondent no formal education 8 5.3 primary 46 30.7 secondary 68 45.3 tertiary 28 18.7 family size number of family members living in the household less than 5 84 56 5 up to 10 62 41.3 more than 10 4 2.7 income average monthly income less than k100 9 6 k100 – k150 30 20 k150 – k200 30 20 more than k200 80 53 expressed as .given this and under the assumption that and , the probability of each one of the cases is given by: using symmetry of the normal distribution: the other three probabilities, the probability that an individual answers are also captured in a similar fashion. then, a log-likelihood function can be used to estimate 𝛽 and σ using maximum likelihood estimation. where , , and, are the dummy variables 1 and 0 denoting the group to which the i th respondent gebremeskel et al. 344 belongs. a given respondent contributes to the logarithm of the likelihood function in only one of its four parts. description of study area our study is conducted in kabwe, one of the 11 districts of the central province of zambia. the specific locality, makululu compound in bwacha constituency, is an unplanned settlement located in kabwe district of lying between latitude 14° 27' s and longitude of 28° 27'e. it is along the great north road, 139 kilometers north east of lusaka. kabwe was established as a lead and zinc mining town around 1902 and almost all of the mines were closed in mid 1990s that created high unemployment and poverty level on sizable residents. the total population of bwacha constituency in 2010 was85, 397that belongs to 17,185 households (cso, 2011:25). the settlement can be described as poor housing units made of mud, with poor sanitation and safe drinking water supply. poor sanitary practices, like disposal of human excreta usually leads to contamination of water and therefore water-borne diseases phiri (2016). majority of the population are not in the formal employment sector with low levels of professional skills and education. we have applied a stratified and systemic sampling techniques for the primary data collection. there are five wards in makululu compound and three wards were considered to reach 150 respondents. these were makululu ward, chililalila and moomba ward. a pre-test was conducted on 5 households to confirm the applicability of the questionnaire in general and the contingent valuation technique in particular. it was found that all the questions including the wtp bids were easily understood by the respondents. for the final data collection, proportionate stratified sampling was applied and each ward had fifty households sampled. results descriptive statistics this section discusses both the descriptive statistics and the regression estimation. it also includes explanations of the variables which are used for describing and estimating the willingness to pay for pipe water connection in bwacha. furthermore, the section discusses the relevant variables used for the wtp estimation. the respondents were given a brief introduction of the benefits from connecting to a commercial water pipe line. a total of 150 respondents were asked double bounded questions with k200 being the initial bid and k100 and k500 were the follow-up bids. we did not find anyone opposed the proposed project of private pipe water connection. table 3 (see annex)shows frequency and percent of selected variables to describe the sample respondents. the sample respondents are more male, educated, and moderate family size & income. table 4 (see annex) shows that majority, 70%, of the respondents are fetching drinking water from communal taps built by the utility company lukanga water and sewerage. the responses on the assessment of water quality shows that 65(43.3%) and 83(55.4%) of the respondents feel that the water quality is good and very good respectively. this perception of the quality of drinking water also reflected by high percentage, 86.7%, of respondents who are not using any water purification method. for three quarter (75%) of the respondents it takes more than 7 minutes to fetch water from the nearest communal tap. out of this percentage, 20% of the respondents need to walk for more than 30 minutes to access the communal tap. a more than 10 minutes walking is usually estimated as more than 1 kilometre (0.6 miles) with a normal walking style of an adult person. majority of our respondents have access to communal taps (70%) as their primary source of drinking water and they perceived the quality as good and very good (98%). the high rating of the water quality correlate with less tendency to use water purification techniques (13%). though the majority of the households have access to communal tap water, they need to walk more than a kilometre. given most of them need to fetch water more than once per day, the time cost of fetching water is high. table 5 below shows frequency and percentage of the double bounded responses as ‘yes-yes’, ‘yes-no’, ‘noyes’ and ‘yes-yes’. the bids were preceded by wtp question stated as: ‘it is difficult to state the actual cost of connecting your household to the nearest water network. the prices stated below are chosen simply for the purpose of our study. if you are willing to be connected to the water system, are you willing to pay a one-off out of pocket payment?’ table 6 shows summary statistics of each independent variable used in the interval regression model which is presented in table 7. these variables are expected to affect the wtp for safe drinking water. water quality, family size, education level and income are expected to have a positive sign in the regression model. regression estimation table 7 presents results from a double bounded intervalregression estimation. we made the estimation using stata’s intreg censored regression command. the table presents the coefficient (marginal wtp), standard error, significance level, and confidence interval. we found that the overall model is statistically significant as measured by log likelihood and wald chi square. most of the estimated coefficients have the expected signs. according to the estimation result, education level and income level of the household are positive in sign and statistically significant at 5% and 1% respectively. 345 afr. j. environ. econ. manage. table 3. water source, perceived quality, purification and estimated time to fetch. variable name description frequency percent source source of drinking water hand dug well 2 1.3 borehole 43 28.7 communal tap 105 70 water quality respondent’s perception of current water quality poor 2 1.3 good 65 43.3 very good 83 55.4 purification water purification method used chlorination 11 7.3 boiling 7 4.7 filtration 2 1.3 no purification 130 86.7 time time taken to fetch water from the nearest source less than 7 minutes 38 25.3 15 – 20 minutes 51 34 20 – 30 minutes 30 20 30 – 40 minutes 19 12.7 more than 40 minutes 12 8 table 4. distribution of double bounded responses for initial amount of k200 and follow-up k500. responses number of responses percentage yes –yes 33 22.0 yes – no 46 30.7 no – yes 33 22.0 no-no 38 25.3 table 5. variables used in the regression and their expected signs. variable type description mean std. dev sign educational level ordered categorical 0 if primary; 1 if basic; 2 if secondary; 3 if tertiary 1.782 .066 + income per month ordered categorical 0 if <k100; 1 if k100-k150; 2 if k150-k200; 3 if >k200 2.217 .079 + family size ordered categorical 0 if 1 – 5; 1 if 5 – 10; 2 if >10 0.60 .057 -/+ distance from the nearest community tap (in minutes) ordered categorical 0 if <7 ; 1 if 15-20; 2 if 20-30; 3 if 30-40; 5 if >40 1.414 .098 + purification nominal 0 = no purification; 1=purification .92 .021 + whereas distance has a negative sign and is statistically significant at 5% mean wtp estimation the estimation of mean wtp is made using the mean values and the marginal wtp values of the variables used in the regression estimation. the estimated mean wtp for the 147 sampled households is k283.7748 ($38.14). the estimate of the mean wtp for the pipe water connection can be used to estimate the total benefits in the specific locality. consequently, we attempted to expand the sample wtp estimate for the population of bwacha. according to the central statistics of zambia (cso, 2011), there were 17,185 gebremeskel et al. 346 table 6. interval regression estimation. interval regression number of obs = 147 wald chi2(5) = 47.31 log pseudolikelihood = -218.0028 prob> chi2 = 0.0000 coef. robust std. err. z p>|z| [95% conf. interval] educ 50.81731 22.35321 2.27 0.023* 7.00583494.62879 income 78.70924 14.73437 5.34 0.000** 49.83042107.5881 famsize 29.74863 23.38308 1.27 0.203 -16.0813775.57863 distance -98.20083 41.97465 -2.34 0.019* -180.4696-15.93202 purify -73.84673 79.13106 -0.93 0.351 -228.940881.2473 _cons 143.1545 97.65233 1.47 0.143 -48.2405 334.5496 /lnsigma 5.220299 .0648312 80.52 0.000 5.093232 5.347365 observation summary: 0 left-censored observations 0 uncensored observations 32 right-censored observations 115 interval observations *significant at 5%, ** significant at 1%. table 7. estimated mean willingness to pay (wtp). mean wtp [95% conf. interval] 283.7748 (usd 38.14) 248.7927 318.7568 table 8. aggregate willingness to pay (wtp) of tap water connection in bwacha, zambia. bwacha residents household mean wtp [95% conf. interval] 4, 876, 669 (usd 655, 466) 92308.54 93210.62 households in bwacha in 2010. multiplying the 810 households by the mean wtp and it yields a total of approximately k4, 876,669 ($655,466), as shown in the following table. discussion of results interval regression model was used to investigate factors determine household’s wtp for tap-water connection. the analysis result also includes the estimation of wtp for sample households and the population. the interval regression model shows that education level and household’s monthly income are the significant explanatory variables at 5% and 1% respectively. this is consistent with other studies (jianjun et al. 2016; parveen et al 2016; twerefou, et al. 2015; mezgebo and ewnetu, 2015; coster and otufale 2014; kwak et al. 2013; khan et al. 2010; mbata 2007) which showed that education and income are significant determinants of wtp. education enlightens people about the importance clean water while income provides the households with ability to pay for the water. the type of purification technique used, the assessment of current water quality and family size found to be statistically insignificant to wtp for private water pipe-line connection. it is found that the mean wtp for sample households is k283.77. this amount is a little higher than the estimated average households’ income that falls in the range k150 – k200. this confirm that the household’s expression of willingness to pay is within their capability to pay. depending on the sign and magnitude of the coefficient of the variable, it is possible to forecast the change in wtp for a unit change of the variable concerned. for instance, the income variable is measured as ordered category between 0 and 3, as one unit change represent a change in income of k50. therefore, based on the mean wtp estimation, a oneunit increase in income category adds k78.70 to wtp. the major contribution of this research is that it adds to the literature on willingness to pay estimation for zambia where there remain evidences of wtp are scarce. to the best of the authors’, this study is the first of its type to 347 afr. j. environ. econ. manage. apply double bounded discrete choice model with interval regression to pipe water connection in zambia. conclusion and policy implications in this study we examine to what extent characteristics of the respondents (the household head) determine the likelihood that they are willing to pay a given amount of money for pipe water connection. the study used a double bounded contingent valuation method to estimate willingness to pay (wtp) for pipe water connection in bwacha constituency, zambia. the main objective of this study was to understand the factors that determine the willingness to pay for safe drinking water in a low income urban settlement in zambia. an interval regression model is used to estimate coefficients of the variable and the wtp. the regression estimation result shows that most of the variables found to have expected signs. among the five variables considered, two variable, namely income and education level of the respondents are statistically significant in determining the wtp for safe drinking water connection. the mean wtp of income is estimated to be k283.77 for a household. the lukanga water company, the sole utility company in kabwe, has a fixed pipe water connection rate based on the distance between a house and the nearest main pipe-line. those houses within 10 meters distance from the main pipe-line are charged k852 and the rate increases as the house located more than the 10 meters distance. our estimation of mean wtp is roughly 33% of the connection charge. the findings of the study are vital for utility company, development partners and local government authorities. the connection charge for most households is ‘expensive.’ nevertheless, our research found that, with some financial or reduced connection charge, it is possible to provide access to safe drinking water to many urban dwellers who are deprived of these essential life sustaining resource for many years. attainment of more years of formal education plays a paramount role in creating awareness about the many advantages of living a healthy life by committing resources by acquiring utilities like water. the study demonstrated the applicability of contingent valuation method to assess the demand and willingness to pay for access to safe drinking water in developing country like zambia. future research works should attempt to use other wtp estimation techniques to extend our findings. disclosure the authors declare no conflict of interest. references aymar, m. (2004). ability and willingness to pay study nwwssc, commercialisation of water supply and sewerage utilities in the north-western and southern provinces. zambia: gtz. celine nauges, d. w. (2010). estimation of water demand in developing countries. world bank. central statistical office. (2011). zambia 2010 census of population and housing. lusaka, zambia. central statistical office. (2015). demographic and health survey . lusaka, zambia: cso. genius, m., hatzaki, e., kouromichelaki, e. m., kouvakis, g., nikiforaki, s., & tsagarakis, k. p. (2008). evaluation consumers' willingness to pay for improved potable water quality and quantity. water resources management, 22(12), 1825 1834. guha, s. (2007). valuation of clean water supply by willingness to pay method in a developing nation: a case study in calcutta, india. journal of young investigators,17. gulyani, s., talukdar, d., & kariuki, r. m. (2005, july). universal (non)service? water markets, household demand and the poor in urban kenya. urban studies, 42(8), 1247 1274. haab & mcconnell. (2002). valuing environment and natural resources. massachusetts, usa: edward elgar publishing, inc. hanemann, w. m., loomis, j., & kanninen, b. j. (1991). statistical efficiency of double bounded dichotomous choice conitngent valuation. american journal of agricultural economics, 73, 1255 1263. lopez-feldman, a. (2012). introduction to contingent valuation using stata. mpra. toluca, mexico: centro de investigacion docenicia economicas (cide0. phiri, a. (2016). risks of domestic underground water sourses in informal settlment in kabwe. environmental and pollution, 5(2). solomon, t., & roy brouwer. (2013). estimation of the public benefits of urban water supply improvements in ethioia: a choice experiment. applied economics, 45, 1099-1108. twerefou, d. t. (2015). willingness-to-pay for potable water in the accra-tema metropolitan area of ghana. modern economy, 6, 1285-1296. unicef. (2014). the rights to safe water and sanitation: current issues. no 3. usa. world health organization. (2016). world health statistics. france. zambia demographic and health survey (zdhs). (2015). demographic and health survey. lusaka, zambia. . in ternationa l scholars journa ls african journal of environmental economics and management issn 2375-0707 vol. 2 (4), pp. 195-197, april, 2014. available online at www.internationalscholarsjournals.org © international scholars journals author(s) retain the copyright of this article. short communication a study of synthetic lignin decolorization ability of p. chrysosporium, t. hirsuta and marine fungi basavapunnaiah naidu1, ranga reddy1, rao koratala satyanarayana2 and venkayya prakasam2 1 department of environmental sciences, faculty of agricultural sciences, delhi technological university, new delhi, india. 2 department of environmental studies, faculty of biological sciences, taleigão, goa, india, goa university. accepted 23 february, 2014 lignin is an organic compound abundantly found in wood. degradation of lignin poses major problems for paper mill industries all over the world with regard to the darkbrown color of lignin in wastewater, which is also a major problem facing the environment today. the decolourization capability was tested with species like phanerocheate chrysosporium, trametes hirsuta and an isolated native marine fungi – m1 using synthetic lignin. the result showed that, isolated strain decreased the lignin color by up to 20% after cultivation for 7 days. where the decolourisation ability of the fungi phanerocheate chrysosporium and trametes hirsuta was observed to 80 and 70% respectively. key words: lignin, decolourisation, phanerocheate chrysosporium, trametes hirsuta. introduction bioremediation is defined as the application of biological processes to the treatment of pollution. most research within the field of bioremediation has focused on bacteria, with fungal bioremediation (mycoremediation) attracting interest just within the past two decades. white rot fungi can withstand toxic levels of most organopollutants (aust et al., 2003). white rot fungi is a physiological grouping of fungi that can degrade lignin (and lignin – like substances). four main genera of white rot fungi have shown potential for bioremediation: phanerocheate sp, trametes sp, bjerkandera sp and pleurotussp (hestbjerg et al., 2003). the main mechanism of biodegradation employed by this group of fungi, however, is the lignin degradation system of enzymes. these extracellular lignin – modifying enzymes have very low substrate specificity so they are able to mineralize a wide range of high recalcitrant organo pollutants that are structurally similar to lignin (cajthaml et al., 2002; mansur et al., 2003; pointing, 2001; veignie, 2004). the fact that these fungal enzymes work extracellularly allows them to access many of the non-polar, non-soluble toxic compounds that intracellular processes cannot (reddy and mathew, 2001; levin et al., 2003). the three main lignin – modifying enzymes are lignin peroxidases, corresponding author email: basavapunnaiah123@gmail.com mn-dependent peroxidase and laccase. all three of these enzyme groups are stimulated by nutrient limitation (mansur et al., 2003; aust et al., 2003). they are most effective at degrading lignin and lignin-like substances when certain nutrient levels, primarily nitrogen are low. conversely, activities of these enzymes are completely suppressed in media containing high levels of nitrogen. this characteristic is advantageous for the fungi inhabiting highly contaminated sites with very low productivity due to toxic levels of organo pollutants (reddy and mathew, 2001). in recent years, many researches indicated that white rot fungus is a promising microbe in wastewater treatment. the basidiomycete phanerochaete chrysosporium in white rot fungi is the most extensively studied and discussed (tien, m. and kirk, t. k, 1983). the extracellular ligninolytic enzymes of white rot fungi have the ability to degrade a wide spectrum of recalcitrant organo-pollutants such as chlorinated phenols and various types of synthetic dyes because of their nonspecific characteristics (heinfling, a et al., 1997; novotny, c., et al., 2001). and some significant mineralization (20%&48%) was observed during degradation of azo dyes (spadaro, j. t et al., 1992). the study of biodegradation of lignin by wood-rotting fungi is limited not only by lack of taxonomy in referring to genetic variety, but also in their potential for industrial use. the studies have mainly focused on basavapunnaiah et al. 195 (before decolorization) (after decolorization) (a) decolorization by phanerochaete chrysosporium in 5 gm/l concentration (before decolorization) (after decolorization) (b) decolorization by phanerochaete chrysosporium in 10gm/l concentration (before decolorization) (after decolorization) (c) decolorization by phanerochaete chrysosporium in 15gm/l concentration figure 1. decolorization by phanerochaete chrysosporium phanerochaetechrysosporium (boominathan and reddy, 1992). until now, selectively few species of basidiomycetes have been used in lignin degradation studies, such as bjerkandera, pleurotus, polyporus, pycnoporus and trametes (addleman and archibald, 1993; paice et al., 1993; eggert et al., 1996). species of marine fungi that may have potential capacity for use in the pulp and paper industry can possibly be used effectively, since these are available in great number along the coastal zones. studies are therefore required in order to determine not only variations in fungal species and lignin degradation capabilities, but also to establish species or strains that may be suitable for biotechnological applications. the purpose of this work was to study the ability of white rot fungi phanerochaete chrysosporium, trametes hirsute and a marine fungus to decolorize synthetic lignin. methodology chemicals all the chemicals used were procured from himedia laboratories pvt.ltd, mumbai, india. microorganisms commercial strains of phanerocheate chrysosporium (mtcc 787), trametes hirsuta (mtcc 136) were procured from imtech, chandigarh, india. a native marine fungal species (here by named as m1) was isolated from the coastal waters of visakhapatnam. culture conditions all the cultures were cultured on pda. the cultures were maintained at 27 0 c and were sub-cultured periodically. decolorization studies comparative decolorization ability of the three fungi was studied by adding commercial lignin. the experimental procedure was as follows. the 7 days, 10 days and 7 days old cultures of phanerochaete chrysosporium and trametes hirsuta and m1 respectively, were inoculated in the medium containing synthetic lignin under sterile conditions. the concentration of synthetic lignin in the culture medium was 2 mg·l -1 , 4 mg·l -1 , 6 mg·l -1 . the decolorization potential of the fungi was observed after 7 days. results the main colored substances of general kraft pulp bleaching effluent were lignin and its related compounds. decolorizing activity by the test fungal species toward a commercial lignin on plate assay is obvious, as shown in figures. in this solid state decolorization, the mycelial growth of the microorganisms and the decolorization patterns were observed to be as follows: phanerochaete chrysosporium: ligninocellulosic materials were able to induce ligninolytic enzyme production in many fungi. the increase in lignin concentration is correlated with the decolorization capacity of extracellular medium. the growth of the fungus started on the third day in the concentrations 5 g·l -1 , 10g·l -1 , where as no growth was observed in 15g·l -1 till seventh day, which may be attributed to higher concentration of the lignin. the growth was observed to be less in comparison with the other two fungi. the decolorization of synthetic lignin by p. chrysosporium was observed to be faster than the decolorization by t. hirsuta and the marine fungi. the decolorization by p. chrysosporium was observed to be more than the other two fungi on the 21 st day of incubation in the concentrations 5 g·l -1 , 10g·l -1 , however the ability decreased at higher concentration. (figure 1). many workers have reported that lignin peroxidase has been shown to be involved in dye decolorization, mainly in p. chrysosporium cultures (bumpus and brock, 1988; cripps et.al., 1990; ollikka et.al.,1993; paszczynski and crawford 1991 and young and yu, 1997). trametes hirsuta: the growth of the fungus started on the eighth day in the concentrations 5g·l -1 , 10g·l -1 , (before decolorization) (after decolorization) (a) decolorization by trametes hirsuta in 5gm/l concentration (before decolorization) (after decolorization) (b) decolorization by trametes hirsuta in 10gm/l concentration (before decolorization) (after decolorization) (c) decolorization by trametes hirsuta in 15gm/l concentration figure 2. decolorization by trametes hirsute where as no growth was observed in 15g·l -1 till eleventh day, which may be attributed to higher concentration of the lignin. the growth was observed to be luxurious when compared with other two fungi. the decolorization of synthetic lignin by t. irsute was observed to be slower than the decolorization by p chrysosporium and the marine fungi. the decolorization by t. irsute was observed to be lesser than p.chrysosporium on the 21 st day of incubation in all the three concentrations. even though the growth was observed to be luxurious the ability to decolorize has reduced with the increase in concentrations of 10g·l -1 and 15g·l -1 (figure 2). sathiya moorthi et.al., 2007 has studied the decolorization capability of t.hirsuta and proved the laccase activity from this fungus through a dark brown color that indicated laccase activity of culture filtrate (well1 glass distilled water; well-2 20 µl of crude enzyme and well-3 30 µl crude enzyme). marine fungi: the growth of the fungus started on the second day in the concentrations 5g·l -1 , 10g·l -1 , and in 15g·l -1 . the growth was observed to be luxurious when compared with p. chrysosporium and less when compared to t.hirsuta. the decolorization of synthetic lignin by marine fungi was observed to be slower than the (before decolorization) (after decolorization) (a) decolorization by marine fungi in 5gm/l concentration (before decolorization) (after decolorization) (b) decolorization by marine fungi in 10gm/l concentration (before decolorization) (after decolorization) (c) decolorization by marine fungi in 15gm/l concentration figure 3. decolorization by marine fungi decolorization by p. chrysosporium. the decolorization by marine fungi was observed to be lesser than the other two fungi on the 21 st day of incubation in all the three concentrations. (figure 3). discussion pointing (1999) showed that qualitative assays are powerful tools used in screening fungi for lignocellulose degrading enzyme production. such tests give a positive or negative indication of enzyme production. they are particularly useful in screening large numbers of fungal isolates for several classes of enzyme, where definitive quantitative data are not required. all fungal isolates were screened for the presence of laccase, lignin-peroxidase and manganese dependent peroxidase activities by using an agar plate assay as a qualitative method for the determination of lignocellulolytic enzyme production (atalla et.al., 2010). with the aim of finding decolorization activity at higher concentrations and because extracellular ligninolytic enzymes have been shown to be induced by growth on natural lignin substrates, the three fungal species were grown in media containing different concentrations of synthetic lignin substrates. in the present study the synthetic lignin decolorization ability of p. chrysosporium, 196 afr. j. environ. econ. manage. basavapunnaiah et al. 197 t. hirsuta and marine fungi were studied. compared with t. hirsuta and marine fungi, p. chrysosporium have shown the highest ability to decolorize. however, the extent of color removal decreased with increase in concentration. decolorization depends upon on the laccase production, media and dyes. similar observation regarding dye degradation by the white rot fungus p. chrysosporium has been observed by spardaro et al. (1992). these results also show that in conclusion, several industrial dyes were decolorized by extra cellular enzymes from different strains of fungi. this appears to be a good application for immobilization and use as a bioreactor for effluent treatment from the dye and printing industries. conclusion lignin, which is widespread in nature, especially in allhigher plants, is a hydrocarbon aromatic compound. its complex structure makes lignin very difficult to degrade and therefore it can be persistent in the environment. lignin degradation is important in the pulp and paper industry worldwide, which uses chemical substances to breakdown lignins in pulp processing. the process releases hazardous lignin-compound effluents into the environment that are toxic and carcinogenic (harazono et al., 1996; elizabeth rodrý´guez, 1999). p. chrysosporium showed the highest ability to decolorize synthetic lignin, the study indicated that the lignin decolorization by marine fungus was competent with the standard species and can provide a cost-effectivess in using native organisms. but further studies are required to prove the ability of the fungi to degrade such very high concentrations of lignin, so that it can be adopted and applied for lignin degradation in paper and pulp mill effluents. references addleman k, archibald f (1993). kraft pulp and delignification by dikaryons and monokaryons of trametes versicolor. appl. environ. microbiol 59: 266-273. atalla m, mabrouk z, kheiralla h, eman r, hamed a, youssry a, abeer aa (2010). screening of some marine-derived fungal isolates for lignin degrading enzymes (ldes) production. agric. biol. j. north amer., 1(4): 591-599. aust sd, swaner pr, stahl jd (2003).detoxification and metabolism of chemicals by white-rot fungi. pesticide decontamiantionand detoxification j.j.p.c zhu s.d.asut a.t.lemley gan, washington, d.c.: oxford university press. 3 – 14. boominathan k, reddy ca (1992). fungal biodegradation of lignin: biotechnological 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human resource management – a review n munu, pa owusu, r kizza, n banadda and i kabenge* department of agricultural and biosystems engineering, makerere university, p. o. box 7062, kampala, uganda. accepted 14 march, 2017 rural-urban migration has put a lot of pressure on governments and private sector actors to provide decent infrastructure in many developing parts of the world. buildings for example, are hastily put up to meet ever growing demand for housing and in so doing raise the risk of accidents at construction sites. the occurrence and widely publicized construction site accidents has attracted a lot of international and local concern. although the challenges are multi-faceted, the role of human resource management (hrm) play a pivotal role in this dynamic industry. as such, the aim of this paper is to review construction accidents with a bias towards better hrm to reduce them in the industry. it can be concluded that proactive hrm in the form of tier ii workforce management strategy significantly solves the construction site accident problems. keywords: construction accident, construction industry, human resource management. introduction the construction industry is one key sector in the economic growth of both developed and developing economies. advancement in commerce, transport, communication, and education is inevitably affected by the level of national construction industry progress. there is ―a highly positive correlation between the growth in construction sector and the overall growth measuring in terms of gross domestic product or gdp‖ (kokkaew and koompai, 2012). this relationship is reported in research carried out in developed economies (citb, 2002; loosemore et al., 2003), emerging economies (kokkaew and koompai, 2012; gürcanli, 2009) and developing economies (jimoh et al., 2017; ogiriki et al., 2017; basheka and tumutegyereize, 2013; okpala and aniekwu, 1988). according to loosemore et al. (2003), construction industry also plays a significant contribution to the world gross gdp. this is easily explained by the fact that major sectors such as chemical process, food *corresponding author e-mail: isakabenge@gmail.com processing, manufacturing, petrochemical, and power generation and transmission are all part of industrial construction (brandenburg, 2006). the construction industry research has seen global interest. the interest is largely attributed to the challenges, potential opportunities, and the import of this industry. construction industry research has been carried out in many countries including but not limited to; us (chini and valdez, 2003; derr et al., 2001; arditi and mochtar, 2000), uk (mccabe, 2007; murray and langford, 2003; construction industry task force, 1998), spain (lópez et al., 2008), new zealand (tran and tookey, 2011), australia (richardson, 2014), turkey (ugur and gürcanli, 2005; gürcanli, 2009), thailand (kokkaew and koompai, 2012; aksorn and hadikusumok, 2008), india (thomas and sudhakumar, 2014), kuwait (kartam et al., 2000), trinidad and tobago (hickson and ellis, 2014), nigeria (jimoh et al., 2017; nkem, 2015), and uganda (alinaitwe, 2006). construction industry research has also been done at international level (du et al., 2007). notwithstanding, the construction industry faces several challenges (ogunde et munu et al. 329 al., 2017; lubega et al., 2000). high frequency of accident occurrence and poor nature of human resource management are two serious challenges in the industry. the rate of accidents in the construction sector is unacceptably high both in developing as well as developed economies. risk of a fatality in the construction industry is five times more likely than in a manufacturing based industry, while it is two and a half times higher in cases of major injury (maraqa and mohamed, 2013; cidc, 2006; davis and tomasin, 1990). according to international labor organization, as cited by aneziris et al. (2012), construction sector contributes about 17% to total world workplace fatalities. in addition to human cost of suffering, the economic effect of an accident can be devastating (mthalane et al., 2008; sawacha et al., 1999). many labor days and hours are lost due to injuries leading to an absence from work. by 2001 in europe, annual direct insurance costs of workplace accidents alone was estimated to be €20 billion and 149 million working days were lost (konkolewsky, 2001). in their research haslam et al. (2005) found that problems arising from workers or the work team and work place issues contributed to 70% and 49% of construction accidents respectively. inadequacy of safety provisions often make individual workers prone to accidents (charehzehi and ahankoob, 2012; lubega et al., 2000; carasco, 1993). these factors are all related to human resource management (hrm) and thus indicate that more studies should be done to understand the cause-effect relationship between hrm and construction accidents. dainty and loosemore (2012) defined hrm as the way people are employed and managed. people management practices remains poorly understood in the construction industry (dainty and loosemore, 2012). management of people within the construction sector has been labeled as complex and problematic given that the applicability of much mainstream human resource management (hrm) theory to this industry is limited (dainty and loosemore, 2012). human resource management in the construction industry is not widely researched and unfortunately the known strategic human resource management has little application in the construction industry either (brandenburg, 2006). in other industries the implementation of strategic hrm practices with other business strategies have been associated with reduced employee turnover (van dierendonck et al., 2016; hashim et al., 2016;sheppeck and militello, 2000; arthur 1994), and higher productivity (wright et al., 1996). but in construction firms hrm has typically been an emergent rather than a strategic or deliberate process (brandenburg, 2006) with hrm activities often regarded as marginal activities (dainty and loosemore, 2012). this is rather unexpected given that construction labor form 7.5% of the world labor force (kulkarni, 2007) and is one of the most people-reliant industrial sectors (dainty et al., 2007). hrm has been previously labeled a vital factor to the aspiration of longterm improvement for the construction industry (kilby and mccabe, 2008; construction industry task force, 1998) and there is a strong connection between hrm performance and project performance (dainty and loosemore, 2012). this is because proper use of human resource management brings about an optimum utilization of other resources (raheem and bankole, 2014). construction industry accidents have significant ongoing cost to employers, workers and society (haslam et al., 2005). construction accidents are unplanned for costs and in addition to human costs involved it may lead to bad publicity that could even make a company uncompetitive in the industry (asanka and ranasinghe, 2016). many have said that effective use of hrm can increase the competitive advantage and help improve the overall performance of construction industry (paauwe, 2004; paauwe and boselie, 2003) currently characterized as a labor-intensive and low-tech sector (kokkaew and koompai, 2012). it is time the construction industry wakes up and solves the hrm problem that potentially will (as discussed later in this paper) significantly address accidents in the industry. there is still a gap in literature to examine the connection between construction hrm and construction accidents. this paper reviews independent literatures on construction accidents with a bias towards better construction hrm. the special aim of this paper is to fill the knowledge gap in the understanding of how effective hrm can be used to minimize construction accidents and hence improve the construction industry especially in developing countries like uganda. sections of the review paper the paper is organized as follows: section 3 is a detailed review of accidents in construction industry. it discusses construction accident global situation and also the factors that lead to immediate accident circumstances. section 4 reviews hrm in construction industry and expounds on hrm practices, policies and processes in the construction industry. section 5 discusses the connection between construction hrm and construction accidents. connections of hrm practices, policies and processes with accidents are discussed separately into detail and suggestions are made on how each can be aligned to ensure minimization of accidents at construction sites. accidents in the construction industry the construction industry is very hazardous worldwide, because of the ―unique dynamic nature, poor conditions and tough environment‖ (aneziris et al., 2012). the industry is often characterized as very diverse, complex and risky (fang et al., 2015; kokkaew and koompai, 330 afr. j. environ. econ. manage. 2012). in 2003, 60,000 fatalities out of a world total of 355,000 workplace deaths, (nearly 17%), were reported in construction section (aneziris et al., 2012). construction accounted for 31% of all deaths when collated with all other uk industries in the year 2002/03 (haslam et al., 2005). a statistical portrait released in 2010 by the european union showed that in 2007 about 4.8% of construction workers in the eu-27 reported having experienced at least one or more accidental injuries at work or in the course of work (silva and šteinbuka, 2010). in 2007 the u.s. construction industry experienced more fatalities than any other industry in the private sector (bls, 2007). japan also reported in 2008 that out of 1,268 fatal workplace injuries, nearly 34% (430 cases) were from construction sector (toyosawa and katsutoshi, 2011), while in india the likelihood to be injured is 16.5% for any of the four million construction workers (goswami and rana, 2011). however the situation looks more alarming given that these published statistics seems to be the tip of an iceberg. in some countries like the uk injuries reported by employers have been stated to be as low as 40% (hsc, 2003). fall from height contributes to majority of construction fatalities (goswami and rana, 2011). haslam et al. (2005) said that in 2002/03 fall from height contributed as high as 46% of construction accidents followed by struck by a moving vehicle 15%. in order to solve the construction accident problem the root causes for it must be identified and analyzed. factors such as failure to ensure safe systems of work, poor maintenance of equipment, use of defective materials, and poor supervision and training have been identified as causes for fatal accidents in great britain hse (1988; 1978). other workplace risks that have been reported to lead to accidents include time pressure, long/irregular hours, poor communication, job insecurity, and discrimination (hse, 2016). research shows that headquarter/managerial, site, and individual factors contribute to accidents in approximate ratio of 1:2:1 respectively (gibb, 2014; whittington et al., 1992) and unsafe behaviour is the root cause of accidents at construction sites (whittington et al., 1992). this is similar to other researchers‘ work that has revealed that individual factors contribute to about 70% level (haslam et al., 2005) and in some cases up to about 80% level (rasmussen, 1997) to accident causation. haslam et al. (2005) believes that in addition to those factors mentioned above, project design also contributes to accident causation. project phase and project progress compared to schedule affect performance expectation from management and hence can lead to dangerous undertakings resulting into accidents. construction accidents do not occur haphazardly. there seems to be a model of causal influences that lead to immediate accident situations. a model for hierarchy of causal influences in construction accidents was developed by haslam et al. (2005). it describes how accidents arise from a failure in the interaction between the work team, workplace, equipment and materials, giving rise to the ‗immediate accident circumstances‘. accident causation starts from distal ‗originating influences‘ such as permanent works design, project management, construction processes, safety culture, risk management, client requirements, economic climate and education provision. these factors influence the development of accident ‗shaping factors‘ of workers, sites and material/equipment that affect the operation of workers, sites and material/equipment. the attitudes, motivations, knowledge, skills, supervision, health and fatigue affect the actions, behavior, capabilities and communication of the work team that may lead in to accident. site constraints, work scheduling and housekeeping of the workplace shape the site layout, noise, lighting, space, temperature and local hazards that may lead to accidents. similarly, the suitability, usability, condition and, therefore, safety of materials and equipment depend on their design, specification and supply/availability. there is a poor safety culture in the construction industry that promotes or fails to inhibit ‗unsafe behavior‘ among the construction workers leading to site accidents (agwu and olele, 2014; dester and blockley, 1995). the three major reasons given for construction workers engaging in unsafe acts, as pointed out by haslam et al. (2005), are; (1) overlooking safety in the context of heavy workloads and other priorities, (2) taking shortcuts to save effort and time, (3) inaccurate perception of risks, with the feelings of invulnerability and ‗it won‘t happen to me‘. it is clear that underlying all of these is inadequate safety knowledge. pointing to deficiencies in safety training among the construction workers. safety knowledge is also needing among construction supervisors at global level (fang et al., 2015). great britain is doing relatively well at international construction accident levels but interviews among construction supervisors revealed that they frequently have little safety awareness and poor understanding of accident causation and prevention (haslam et al., 2005). the diversity, complexity and risky nature of the industry makes it less attractive for young people to enter into the construction workforce. this aggravates the problem of lack of skilled workers (kokkaew and koompai, 2012; tressell, 1914/1957). to maximize effectiveness of human resource management in the heavily peoplereliant construction industry, kokkaew and koompai (2012) suggested that there should be consideration of safety and health. essentially, human factors are involved in most safety failures thus the need for proper understanding of the hrm in the construction section. hrm in the construction industry raheem and bankole (2014) defined human resource management (hrm) as ―the planning, organizing, munu et al. 331 directing and controlling of the recruitment, compensation, integration, sustenance, and separation of man power resources to an end best suited to the achievement of organization, and individual objectives.‖ construction human resource is therefore the managerial and technical workforce required for construction (raheem and bankole, 2014). in order to effectively manage the human resource, hrm utilizes different practices, policies, and processes depending on the organization‘s tastes and interests. hrm is important in all organizations including construction (kilby and mccabe, 2008). it contributes to organizational success (huselid, 1995) and creates competitive advantage for the organization (amit and belcourt, 1999). armstrong (2006) said that people are the most valued asset for an organization. people contribute to the achievements of organization‘s objectives both individually and collectively and deserve to be treated in a way that reflects so. hrm helps to create this environment by changing the attitude and behavior of employees toward the organization hence better organization‘s performance is often realized (kokkaew and koompai, 2012). for an industry such as construction with productivity studies revealing below average performance (zhang and liu, 2006; liu et al., 2006), the proper understanding and application of hrm is very vital. project-based culture, temporary teams and fragmentation that are commonly mentioned as major causes for the poor performance are just indicators of the poor human resource management and understanding within the industry. hrm is understood and discussed largely in large, stable organizations that are classically managed. however, in organizations that rely principally on projects such as construction, hrm is often marginalized in discussions about what it is and how it should be practiced (huemann et al., 2007). this is because much of mainstream human resource management (hrm) theory is not applicable to this industry (dainty and loosemore, 2012). huemann et al. (2007) stated that certain specific features of project-oriented companies make hrm in such organizations different from the traditional hrm processes and practices for the classically-managed organization. the specific features of project-oriented companies include; (1) ―managing by projects‖ as a strategy of project-oriented companies, (2) temporary nature of projects, (3) dynamism, (4) project-portfolio resource and multirole demands and (5) specific management paradigm. in ―managing by projects‖ the hrm policies, processes and practices must somehow be supportive of project orientation and therefore it is different from traditional hrm for classically-managed organizations where the emphasis is not on projects but instead on routine products and services with welldefined and stable job requirements (huemann et al. 2007). due to the temporary nature of projects when a new project is introduced or an existing project is stopped, there is a change in human resource requirement and hence change in overall human resource configuration of the company. this is quite different from the classically managed organizations where the human resource configuration is relatively stable. the following sections will expound on this difference by discussing in detail hrm practices, policies and processes in the construction industry. hrm practices in construction industry human resource management practice is a management process of an organization's human resources. it aims to establish a more open, flexible and caring management style so that staff will be motivated, developed and managed in order to maximize their contributions to organizations‘ objectives. consistent planning, monitoring and evaluation are key for the progress of hrm (raj and kothai, 2014). successful implementation guarantees that all employees know their roles and responsibilities, and also feel part of the organization which is able to meet their expectations as well as the objectives of the organization. construction working conditions became terrible during the industrial revolution in which building projects soared and workers were forced to work beyond their capacity. however they were paid relatively well though insufficient. following the two centuries after industrial revolution, construction rate reduced. hence pay, conditions and the prospects of workers through training and development fell to the smaller organization (kilby and mccabe, 2008). construction industry became unattractive and characterized as a labor-intensive and low-tech sector dominated by unskilled labor force. the employee turnover became high and there is a general need to develop good understanding of the hrm practices to improve this. many current hrm practices can be traced to the needs of companies in the 1950s to develop and retain talent (cappelli, 2015; grattonet al., 1999). employee motivation through workers participation, team belonging, recognition, management and commitment, and effective training schemes in the construction industry have brought about an increase in efficiency and effectiveness of the workers (raheem and bankole, 2014; yankov and kleiner, 2001). and it is the theory that is widely accepted in the u.s. construction industry. motivation being the inner power in the process of human resource enhancement is of much interest to construction managers as a tool to achieve an organization‘s goal (kokkaew and koompai, 2012). in europe, financial matters and also psychosocial factors affect the work rate of the workforce in the construction industry (arashpour and arashpour, 2011). dainty et al. (2007) said that the hr practices in construction industry are still informal. the industry is described as a craft labor market. to shift 332 afr. j. environ. econ. manage. the industry to an occupational labor market clarke and herrmann (2004) suggested a package of formal hr practices for directly employed staff coupled to an industry-wide training and obligatory skills certification scheme. in this way, the hrm provides good training and development opportunities for employees to enhance individual skills and flexibility of roles (mullins, 1999). this will improve the confidence and work standard among the construction workers. hrm policies in construction industry human resource policies are strategies on the approach the organization aims to adopt in managing its people (armstrong, 2001). it states the intent of the organization about aspects of human resource such as recruitment, promotion, compensation, training, and selection (durai, 2010). in construction there is a mindset in which workers are seen as ‗commodity‘ that can, at best, be effectively managed using personnel policies and procedures; at worst they are simply ‗hired and fired‘ and it is difficult to confront such a culture (kilby and mccabe, 2008). employees are the most precious resources in the construction industry (kilby and mccabe, 2008) so policies and guidelines that an organization intend to adopt should be able to address the welfare of the workforce. however, in most construction industries, employees are not considered as the greatest assets and are not being treated as such. this can be witnessed in the general industry policy on employee hiring and payment. there is common use of casualized employees who are usually employed and paid based on output but without any deduction for tax, insurance and pension contributions that are left as the responsibilities of the worker (kilby and mccabe, 2008). this was the cause of the national building strike of 1972 in britain in which such a policy was fought to be abolished. in the construction sector, the needs of the people are subjugated by performance concern (dainty and loosemore, 2012). thus employee interests are not of primary concern. this has potentially dire consequences for those who work in the industry, for the organizations that employ them and eventually, on the prosperity and productivity of the industry as a whole (dainty and loosemore, 2012). for the construction industry to be successful, there must be a fine line between companies‘ interests and employee well-being. in the dynamic environment in which the human resource configuration is constantly changing, the challenges of ensuring employee‘s well-being and proper treatment of workers is important (huemann et al., 2007). it is therefore necessary to consult, discuss and agree with the employee representatives before implementing any human resource policy. the casual nature of recruitment in the construction industry is encouraged by decentralized system of recruitment common in most construction firms. in decentralized recruitment system, recruitment is done at both the head office and the site office (raheem and bankole, 2014). in such a recruitment system formalization of the process is very difficult (brandenburg et al., 2006; maloney, 1997) and application of strategic planning is hard. maloney (1997) defined strategic planning as a process whereby the objectives of an organization are developed and the actions required to meet those objectives are identified. with a strategic policy in place to ensure meeting clearly defined company objectives, there is little room for informal and workforce casualisation. strategic human resource planning is possible in construction firms and leads to higher organizational performance, including higher productivity, greater cost effectiveness, and greater overall efficiency (ferris et al., 1990). hrm processes in construction industry hrm processes are the courses through which workers are subjected by an organization in order to better contribute to organizational objectives. it starts with the way that the employees are obtained, then their development through trainings and all the other organizational aspects of improvement that are available. it also ensures that there is career structure to keep them in the organization (kilby and mccabe, 2008). in the construction industry, non-standard employment is common accounting for around half of the industry‘s total employment (loosemore et al., 2003). recruitment is done both at the head office and at the site. however, recruitment at head office seems to be focused on construction management and technical staff while site workers are mainly recruited at sites (raheem and bankole, 2014). on the job training is the most practiced method by construction firms for training and development of human resources especially for site workers (raheem and bankole, 2014). full-time well educated highly skilled permanent workers are more likely to receive training (including long-term) than their insecure and unskilled colleagues (forde et al., 2005; cully et al., 1999). this can be attributed to the hefty reliance on self-employment in the industry. casualization of the recruitment process makes employers reluctant on training employees since their stay at the company is deemed only temporary and may not last long enough for the training investment to be realized (dainty and loosemore, 2012; dainty et al., 2007). according to kokkaew and koompai, (2012), in order to maximize the effectiveness of human resource management in construction industry, strategic human resource management, job analysis, training and development as well as performance management are key. these require detail planning by an organization especially before an employee is recruited. munu et al. 333 the organization should be clear on the skill requirements, roles, possible future trainings and how performance measurement will be conducted well before an employee is recruited. through this, employee quality can be ascertained which will ensure longevity in the organization. this form of strategic planning answers the three key r-aspects (respect, recruitment and retention) that were called for in ‗respect for people‘ (mccabe, 2007). this is also in line with the recommendation of raheem and bankole (2014) who pointed that to foster quality production and ensure excellent professionalism in construction, workers should be recruited through the human resource department after satisfying all criteria for selection of workers for that particular work. good trainings and development to improve construction techniques can be achieved through frequently organized seminars and trainings by the human resource department. the two-tier approach for construction hrm a two-tier approach has been developed and proposed to improve hrm in construction section. the approach consists of two workforce management strategies; tier i which was developed by construction industry institute (cii) and tier ii which was developed by center for construction industry studies (ccis) at the university of texas at austin. tier i tier i is a hrm approach designed to efficiently manage standing workforce, irrespective of its skill level. the focus is on organization, communication, and utilization of field management (brandenburg, 2004). tier i strategy improves the effectiveness and productivity of the construction workforce through effective supervision and project management (brandenburg, 2006). supervisors (including general foremen, foremen and super intendants) must have strong management abilities to effectively coordinate and manage their team. management, communication, and technology utilization are emphasized at all levels of the project. characteristics of tier i were summarized by brandenburg (2006) as shown in table i. tier ii tier ii is a revolutionary and future-oriented hrm approach designed to enhance workers‘ value by increasing their skills and productivity (borcherding et al., 2001). the goal of this increased value is increased wages and longer careers in the industry (brandenburg, 2006). this approach also ensures formalization of recruitment processes which is key in solving hrm issues in an industry that has a tendency to transfer power away from centralized personnel departments to site managers. it promotes the need to train, develop, and retain workers because of their increased value. tier ii solves the widespread problem of ‗hiring to fire‘ in which many workers are hired as casual laborers. casual laborers are poorly skilled and with little or no idea of the standards and working practices. tier ii provides effective training and development opportunities for all employees. this enhances personal skills and multi-skill capability (du et al., 2007) and develops not only the company but the industry in the long run (ramlall, 2003). in the present construction industry, the cost of labor accounts for a significant portion of the total construction cost (loosemore et al., 2003) but tier ii lowers labor costs because fewer workers are required on site (tucker, 2001). a higher productivity is realized through more effective human resource management without compromise or sacrifice of the construction work (kokkaew and koompai, 2012). characteristics of tier ii were also summarized by brandenburg (2006) as shown in table i. hrm and construction accidents hrm and accidents in construction industry are strongly linked because accidents involve human aspects in one way or the other. lubega et al. (2000) said that accidents in construction include not only direct physical injury to persons or damage to property but also short and long term effects or incidents due to other exposures on sites that affect the worker‘s health and physical well-being. the profession of construction became common place to death and injury during the industrial revolution. there was a lot of work to do and profit became more valued than workers‘ conditions and safety (mccabe, 2007). during this period subcontracting became common. there was little training given to employees who were in demand. subcontractors were under pressure and would press supervisors/gangers to force their men to work faster and take risks and injuries increased (mccabe, 2007). nevertheless a research done by coleman (1991) revealed that nearly 90% of all construction accidents leading to death can be prevented of which positive management can contribute up to 70%. sawacha et al. (1999) named top five important issues that are associated with site safety. interestingly all these are related to hrm in one way or the other. they are (1) management talk on safety, (2) provision of safety booklets, (3) provision of safety equipment, (4) providing safety environment and (5) appointing a trained safety representative on the site. in addition to these we add the aspect of (6) personality/individuality that contributes to 70% or more cases of accidents (haslam et al. 2005). hrm practices and construction accidents management talk on safety is a measure of top management commitment to workers‘ safety. previous 334 afr. j. environ. econ. manage. table 1. tier and tier ii characteristics. tier i tier ii highly skilled front-line supervisors in all crafts highly skilled journey-level workers in key crafts single-craft journey-level workers multi-craft journey-level workers no pay differential to workers for skill workers are paid a higher wage for their higher skill level traditional top-down management structure proactive, horizontal management structure strong communication between supervisors and managers strong communication between journey-level workers and project managers information technology used extensively at supervisor and project management level information technology used extensively at all levels large labor pool available (possibly unskilled) skilled labor pool available management, computer, planning training available to supervisors only management, computer, planning training available to journey-level workers task training available to all workers craft training available to workers traditional hierarchical work environment at crew level in all crafts high performance work teams utilized at crew level (for key crafts) source: (brandenburg, 2006). research has shown that avoiding engaging in risk-taking behaviors was related to enhanced feelings of workers‘ responsibility for safety and more positve assessment of senior management commitment (yule et al., 2007). frequent communications about safety by top management make the workforce feel that they are valued by the management and hence risk-taking becomes minimal. having a clinic/first aid rooms at the site can also depict the level of management commitment to safety. supervisors or front-line managers are key individuals in accident prevention. in their daily contact with staff they have the opportunity to control unsafe conditions and acts leading to accidents (simard and marchand, 1994; chew, 1988). in other words they set the tone for the work atmosphere and hence safety climate for their operatives (flin et al., 2000). personal involvement and participatory involvement by supervisors with their workforce in safety activities rather than a centralized bureaucratic relationship also seems to promote safety (simard and marchand, 1994). in their research, shannon et al. (1997) found that good relations between management and workers was consistent with lower injury rates. appointment of a safety manager (simard and marchand, 1994) and a safety committee (flin et al., 2000) help in creating a safety system in the company. the hrm department‘s role is to ensure and enforce safety by recruiting safety manager(s) and establishing a safety committee. supervisor evaluation for performance and rewards should also include assessment of level of participatory involvement and safety talks given to workers and also the number of injuries registered among his/her crew members. haslam et al. (2005) pointed out that economic climate is an originating influence to construction accidents. timely payments and rewards show the level of commitment to, and value placed on, the workers and are crucial for productivity (kilby and mccabe, 2008). it creates an environment where workers are less stressed, happier and focused on fulfilling company goals. on the contrary poor and untimely payments tend to increase the risk of injury. workers should frequently be monitored and assessed based on their attitudes towards work. unsafe and unscrupulous behaviors that can lead to accidents (personal or workmates) shouldn‘t be tolerated with possible dismissal. we discuss other practices such as employee motivation and training under hrm policies and processes in relation to construction accidents respectively. hrm policies and construction accidents in their research, sawacha et al. (1999) found that safety performance in the united kingdom construction industry was most dominantly influenced by organizational policy. poor hrm policies in construction can be traced back to during the industrial revolution. during this period the culture of the emerging industry was shaped into one in which speed, agility, and fearlessness became the prized attributes (kilby and mccabe, 2008). casualization of employment process became common. workers were hired to be fired at the end of projects. this is still the status quo in today‘s construction section (kilby and mccabe, 2008). with this type of mindset, employee perception of the value the organization places on them is reduced and this can in some cases increase the chance of risk-taking (yule et al., 2007). high employee turnover is also associated with such a culture and with it increased injury rates (shannon et al., 1997). employee turnover and injury rates are associated by the learning curves, new experiences and mastering of a new job. strong hrm policies that ensure centralization and formalization of the recruitment process for longer retention can contribute to solving this. employees should also be insured against accidents. munu et al. 335 hinze and gordon (1979) found that supervisor-worker relationship affects injury rate. the hrm department must constantly nurture, monitor and reward this relationship to create a better working environment. incentives for safe operation should also be given at personal and team levels (konkolewsky, 2001). outsourcing and subcontracting do not guarantee skills and performance and may impair organization‘s ability to control some processes making it difficult to implement coherent hrm strategies (dainty and loosemore, 2012). construction firms (including large firms) should focus on creating and developing their own human resource base. policies on working conditions must be clear. compromised safety is linked to tiredness and fatigue leading to reduced concentration (haslam et al., 2005). bonus pay and overtime works should be discouraged. bonus payments can lead operatives to achieve higher production through performing unsafely (sawacha et al., 1999). it is a motivation to work faster and thus encourages the use of unsafe methods like risk-takings. leather (1983) found that 67% of foremen and 43% of housing managers in the public sector group did consider bonus targets to be a major contributing cause of risk-taking and corner-cutting by the direct labor operatives. hrm can indirectly reduce the rate of accidents that occur from overtime works and productivity bonus pay by assigning moderate amounts to overtime works and productivity to discourage such activity from happening in the organization. assigning high overtime payment may have negative implication on project schedule and accidents as the workers may intentionally slow their work during the norm time in order to be caught behind schedule and hence earn overtime and productivity bonus payments. when it is deemed necessary to assign productivity bonus, a safety bonus is advised instead as it combines productivity and safety performance as a goal for reward (sawacha et al., 1999). hrm processes and construction accidents many of the accidents in the construction industry arise from workers‘ negligence, ignorance, and carelessness (lubega et al., 2000). understanding employee personality, capability and talent is vital for accident prevention in construction industry. it should guide the hrm department to decide acceptance for recruitment based on possibility of required future trainings to ensure required safety climate in the organization. where coordination is required, poor command of local language can impair safety and productivity (haslam et al., 2005). sawacha et al. (1999) found that a strong correlation between care for personal safety and safety performance exists and employees who are concerned about personal safety in their work approach have better safety record. hrm department should include safety among the factors evaluated during interviews and tests for the selection into the organization and also during assignment to a given project. language and personal safety history should also be considered. there is a strong relationship between age and experience and level of safety performance of workers. younger workers register more non-fatal accidents than older ones (sawacha et al., 1999; salminen, 2004). the trend falls steadily to reach a low point in mid-forties. this is because the older the operative gets the more experience and safety requirement awareness gained. however older persons seem to be more subject to fatalities than younger ones. jeong (1998) found that workers aged 45 and above have highest number of injuries. this could be because of lack of mental agility, sensory deficiencies, and the longer time required by the older worker to learn when put into a new situation (pratt et al., 1996). seniority of workforce is consistently related to lower injury rates (shannon et al. 1997). employees are more prone to accidents in the first years of their work with an employer. jeong (1998) found that 95.6% of nonfatal injuries and 92.5% of deaths occurred during the first year of employment. experience and age should be factors of consideration during selection for recruitment into the company and assignment of workers to construction projects depending on project type. preemployment screening/health surveillance should also be done to take only healthy and capable workers. tasks that are considered ‗dangerous‘ should have only experienced and aged workers controlling or supervising it or even working on them. it may require an extra effort from the hrm department to secure such a service by searching for the required expertise or outsourcing. this can seem expensive or waste of time from a layman‘s point of view. but may prove more economical in the long run taking into account the direct and indirect costs the organization would incur in event of probable accidents when working with inexperienced employees. factors such as loss of company‘s image due to frequency in accidents, fatalities of employees and legal cases can prove more expensive in the long run. on the other hand the accumulation of loss of working hours and days and poor publicity due to accidents is more costly to the organization. when deciding whether to work with a relatively cheap inexperienced organization employee or employ and/or outsource experts for the particular task, the hrm department should consider all the risks involved. safety trainings amongst workers was reported to be important in preventing accidents in the work of hale (1984). however most construction firms have not adopted safety trainings. in a research done by (sawacha et al., 1999), ninety-two percent of operatives reported that they have been asked to operate machinery without adequate training. the use of both short-term and long-term training at places like training centers, rather than on-the-job training is more beneficial (tabassi and 336 afr. j. environ. econ. manage. bakar, 2008). effective training is an important factor for implementation of hrm in construction projects (tabassi and bakar, 2008). lópez et al. (2008) concluded that workers in different work age group may require different specific trainings. during the separation phase, the hrm department should come out with a strong way forward that reflects the company‘s commitment and love towards the worker for his service. this may include financial help and frequent communication. when a worker is fatally injured or injured to the level that he can no longer serve the company, special benefits can be conferred on the family depending on the service he/she has offered to the company. hrm and ohs in construction industry occupational health and safety (ohs) is a component of hrm (zanko and dawson, 2012). successful management of ohs is crucial to the construction industry because of the direct and indirect costs of mobilizing human resources. a number of disciplines have helped to further the knowledge of ohs. despite the many developments, a challenge still remains to improve the skills of managers and make them aware of their responsibilities on the subject of preventive and corrective measures to improve occupational health and safety. gravel et al. (2013) revealed that ohs problems are related to difficulties with work organization, management, wearing of protective equipment, harmonization of work methods and physical or psychological overwork. recruiting and retaining a competent workforce, poor work relations, increased absenteeism and staff turnover, and lack of work/family balance are the problems associated with hrm (gravel et al., 2013). the impact of increased workload on employees‘ mental health can be measured from the angle of imbalance: (1) job demands-control imbalance (karasek model) and (2) effort-reward imbalance (siegrist model). vézina et al. (2006) said these imbalances are indicators of perceived poor health. it is vital that managers in the construction industry understand the economic and organizational issues associated with ohs and that they master the associated problem-solving processes. in addition, managers must be able to critically analyze risks and mobilize human and material resources to overcome them in a lasting way. some workers believe that the failure to wear/use safety clothing and equipment ought to be punishable offense through sanctions imposed on the offender. they suggested that such a sanction should be written into the contracts of employment (sawacha et al., 1999). in another study, (shannon et al., 1997) also found that good housekeeping was consistent with lower injury rate among workers and konkolewsky (2001) pointed to the importance of highlighting danger spots. tier ii and construction accidents a quick summary of the discussions of the hrm practices, policies and processes in relation to construction industry accidents points out the following among others: (1) recruitment of safety manager(s) and establishing a safety committee, (2) timely payments and rewards, (3) assessment of rewards to include supervisor participatory involvement, safety talks given and number of injuries among crew members, (4) centralization and formalization of the recruitment process for all workers with employee retention focus, (5) insurance of employees against accidents, (6) standardized salary scale where employees are paid on guaranteed monthly basis not based on work load performed, (7) encouragement of standard working hours (for example eight hours per day), (8) discouragement of bonus pay and overtime works by lowering rates, (9) consideration of employee personality, capability, talent and injury history during recruitment, (10) creation and development of a company‘s own human resource base through frequent trainings and talks, (11) promoting seniority of workforce, and (12) avoiding on-the-job training but upholding regular safety trainings at places like training centers. considering all these factors and the characteristics of tier ii workforce management strategy, it therefore follows that tier ii workforce management strategy if properly implemented is better suited and positioned to significantly reduce accidents in the construction sector. it has few multi-craft highly skilled journey-level workers who are satisfied because they are highly paid. they are better trained and are not under pressure of job insecurity and they feel that they are valued by the organization/company. workers under tier ii approach are therefore well placed to avoid accidents during construction. conclusion this paper reviewed accident situation and hrm literatures in construction industry. it also examined how hrm can be used to mitigate construction accidents. proactive hrm is the way to go for construction industry for efficiency, effectiveness and safety. the impact of proactive hrm has already been felt and contributing towards making british construction more effective and efficient (kilby and mccabe, 2008). the concept of hiring to fire promotes unsafe behaviours and should be fought in the construction industry. prioritization of employee retention will help in fighting accidents. employees should only be recruited in a formal process under the hrm department after passing all selection procedures and requirements of which safety concern should be highly weighted. project managers shouldn‘t be allowed to employ without the consent of the hrm. munu et al. 337 there is a strong need for policies on continuous human resource development (hrd) programmes to be put in place by construction companies and also ensured through government policies. on-the-job trainings should be discouraged as it is a form of experimentation on human beings with possible dire consequences. appointment of safety managers and participatory involvement of supervisors is 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http://construction-institute.org/scriptcontent/cpi2001slides/tucker_cpi.ppt http://construction-institute.org/scriptcontent/cpi2001slides/tucker_cpi.ppt http://dx.doi.org/10.3390/admsci6040018 african journal of environmental economics and management vol. 1 (1), pp. 013-021, august, 2013. available online at www.internationalscholarsjournals.org © international scholars journals full length research paper land use pattern and sustainability of food crop production in the fadama of southern guinea savanna of nigeria a. f. lawal 1 *, o. a. omotesho 2 , and m. o. adewumi 2 1 department of agricultural extension and management, college of agriculture, mokwa niger state, nigeria. 2 department of agricultural economics and farm management, university of ilorin, kwara state, nigeria. accepted 2 april, 2013 an assessment of the sustainability of food crop production in the fadamas of southern guinea savanna of niger state, nigeria was carried out within the framework of small-scale farming households utilizing fadama for the cultivation of food crops. the study determined profitability of food crop production in the fadama and identified the pattern of land use and management and its effects on sustainability of fadama. a twostage simple random sampling technique was used to obtain 149 food crop farming households interviewed for the study. the data were analyzed by using descriptive statistics such as frequency distribution, mean, standard deviation, in addition estimates of crop diversification index (cdi), nutrient intake index (nii), ruthberg index, farm budgeting model was made. a typical household hectared seventeen persons and planted an average of 3.44 ha scattered in three plots. the major enterprises were sole crop rice and maize – based mixtures in about 0.70 and 2.59 ha respectively. estimated mean cdi was 0.651 implying stability of income and sustainability of mixed crop enterprises while mean nii was 1.89 showing that combined crops hectareve low tendency to deplete soil nutrient. the ruthberg index value of 0.393 implied that a six years fallow period alone may not be adequate to restore natural fertility. the farm budget analysis showed thectaret the sampled fadama food crop farming household hectared positive net return for all enterprises. maize/cowpea enterprise hectared the highest gross margin of n25, 663/ ha while leafy vegetables (for example spinach) hectared the highest return on investment (2.39). the average return on investment for all the farms studied was 1.89. mixed cropping the dominant cropping system generally adopted by the fadama farming households gave higher gross margin per hectare. the study concluded that production of food crop in the fadama of the guinea savanna of niger state, nigeria is sustainable. mixed cropping, consolidation of household resources, increased use of animal traction and organic fertilizer as well as integrated pest management is recommended. in order for the foregoing to be effective, they must be accompanied by improved extension service delivery, aggressive adult education programme, regulated use of agro-chemical, improved access to credit and availability of subsidized inputs. keywords: fadama, sustainability, mixed cropping, land use and management introduction background to the study fadama are seasonally flooded plains along major rivers or depressions on adjacent low terraces. they are fertile, *corresponding author. e-mail: funsolawal@yahoo.co.uk reduce the risk of crop failure and hectareve potentials for longer period of agricultural activities in a year. they pre-sent a unique opportunity towards reversing the declining per capita food production in nigeria. however, develop-ment intervention, changing land tenureship and population pressure have been identified as threats to this valuable but delicate land resource the fadama size of nigeria is estimated at about 4.6 million ha. out of this, niger state hectares an estimated 495,000 ha. this is second to adamawa state with 625,000 ha, the largest in lawal et al. 013 the country (ingawa, 1998). if the potential of the inland valleys for intensive crop production could be realized, they might serve as a kind of safety valve for relieving pressure in other agro ecosystem particularly the humid forest and moist savanna (world bank, 1992). research problem the quest for harnessing the benefit of fadama land hectares ushered in technological innovations such as development of small irrigation pumps, small earthen dams and shallow tube wells. these hectares led to intensification in the use and management of fadama for agricultural activities. by and large, the inland valleys are cultivated by small holders whose land utilization and management with limited resources are aimed at achieving farm level objectives in terms of food security and economic viability. their land use practices have a short term planning horizon with little attention to the status and management of agricultural land (krusemen et al., 1996; pannell and glenn, 2000; adewumi and omotesho, 2002). production objectives of short term food security and income that guarantees economic production by the farmer might be achieved. however, the achievement may hectareve come at the expense of long-term sustainability of land resources and development. sustainable development is consistent with increasing environmental assets or development without destroying the future of natural capital stock. the most critical issue that this paper addresses is whether fadama land utilization is consistent with sustainable development in view of some factors threatening sustainability around the fadama of northern nigeria. kolawole (1991) reported that development intervention, changing land tenureship and population pressure were among the factors threatening sustainability of fadama in nigeria. lawal (2001) also reported that the construction of hydroelectricity dams at jebba and shiroro hectareve hectared adverse effect on socio-economic lives of the riparian communities. this hectare led to the loss of crop and farm land to flooding as a result of flash-flood occasioned by opening of the dams. the potential of fadama area will remain elusive until the sustainability of this agro-ecosystem can be assessed which is the focus of this study. therefore, some questions become fundamental in the assessment of fadama land use; are the farming practices adequate to improve soil fertility, nutrient recycling and enhance sustainable production? (2) can the present cropping practices enhance economic benefits? (3) is food crop production in the fadama sustainable? a work that assesses sustainability of food crop production in fadama at the small holder farm level is relevant in determining the extent to which the low external input agriculture (leia) farming households in the fadama allocate, use and manage this delicate land resource. the work is necessary to provide information to policy makers in assessing the economic rationale of different land management options in order to maintain the bio-physical condition of the land. it is against this background that the study on which this paper is based was undertaken. objective of the study the objective of the study is to determine costs and return to food crop production in the fadama, identify the patterns of land use and evaluate its effects on the sustainability of fadama in food crop production in the southern guinea savanna of nigeria. economic concept of sustainability the unpriced outputs of agricultural system both positive and negative have become of increased importance as compared with conventional marketed outputs. there is concern that, while technical changes have brought major benefits to consumers in terms of reduced food prices, some developments hectareve taken us into unsheltered waters. nix (1990) pointed out that the idea of sustainability is central to attempts to define farm income. he quoted hicks (1946) who defined income as that which could be consumed in a given period leaving the consumer as well off at the end of the period as at start. recent theories of economic growth have built upon neoclassical foundation (solow, 1992) and recognize that aggregate capital (k) consists of man made capital (km), natural capital (kn), human capital (kh) and social capital (ks), such that; k = km + kn + kh + ks (1) the quantity and quality of this capital determines the level of provision of utility for mankind on a year by year basis (pearce, 1999). the notion of sustainability arises when it is required that the capacity of k to produce utility from one period to the next does not decline. important modifiers to k include technological change, which may be regarded as endogenous or exogenous and population growth, which may hectareve positive or negative impacts on the component of capital (webster, 1999). the distinction between weak sustainability and strong sustainability hinges upon whether substitution is permitted between the components of k. weak sustainability implies that substitution may take place in order to maintain k. in other words, rates of substitution or elasticity’s are assumed to exist. in contrast, strong sustainability does not permit substitution between components of k and the emphasis is placed on conserving kn (and each of its separate sub-components) at all costs. arguments for such an approach include irreversi 014 afr. j. environ. econ. manage. bility of some changes in natural capital for example species extinction (tversky and kahneman, 1981). it is further argued that natural capital is impossible to value by whatever means and that no trade-offs could be made within kn or any level of subdivision of kn. however, vander hectaremsfort and latacz-lohnman (1998) have argued for strong sustainability on the basis of the second law of thermodynamics (the entropy law), which implies a limit to the stock of energy available to mankind for transforming low entropy natural capital through manufactured capital to high entropy waste products. it is argued that that km and kn should be complements rather than substitutes. methodology area of study the study was carried out in the fadama areas of niger state, in the southern guinea savanna of nigeria. the fadama along river niger and river kaduna and other minor rivers and floodable plains in niger state were used for the study. niger state lies between longitude 8°11’ and 11°20’ north of the equator and between 4°30’ east of the equator. it covers an estimated land area of 4240 km sq. the vegetation of the state is mainly southern guinea savanna. the mean annual rainfall ranges between 1110 mm in the north and 1600 mm in the south. the average annual number of raining days ranges between 187 and 220 days. the rain starts in late april and ends in october with the peak being in july. the average minimum temperature is about 26°c while the average maximum temperature is about 36°c. the mean humidity ranges between 60 (january to february) and 80% (june to september). the vege-tation supports the cultivation of root crops and grains. the predominant crops are; rice, sorghum, millet, yam, groundnut and cotton. method of data collection data used for this study were from both primary and secondary sources. the relevant primary data were obtained through a farm management survey of fadama food crops farming households conducted between august 2004 and september 2005. the main instrument for data collection was structured interview schedule. these were administered on head of fadama food crop farming households by trained enumerators under the supervision of the researcher. the data covers farming activities for the 2004 cropping season. data collected covers information on fadama food crop farming households head characteristics (age, level of education, family size etc), land use and management practices, input and output data, as well as their prices, crop combination and diversification etc. sampling procedure the target population for this study is the fadama food crops farming households in niger state, southern guinea savanna, nigeria. a two stage simple random sampling technique was used to select sample for the study. the first stage involved the random selection of fadama farming villages in the three adp zones of the state. the 1991 fadama village and households listing of niger state agricultural development project (nsadp) served as the sampling frame for the selections. about five percent of the total fadama farming villages were randomly selected for the study. the second stage of sampling involved the random selection of fadama farming households. about 10% of the fadama farming households in each of the selected villages were sampled for the study. the villages and households selection was based on the proportion of fadama food crop farming households in the nsadp zones and the villages respectively. a cross sectional data from 149 fadama food crop farming households were collected for study. analytical techniques combinations of analytical techniques were employed in this study. descriptive statistics such as mean, standard deviation, frequency distribution were used to capture the socio economics characteristics and pattern of land use management. in addition to descriptive statistics the following indices were calculated to further investigate the influence of pattern of land use and management on sustainability of fadama land. crop diversification index (cdi) stability of yield and revenue from crop planted are indicators of sustainable farm practice, this was captured with crop diversification index. the crop diversification variable was measured in this study by the herfidahl index given as; n 2 cdij = (1) pi j i 1 where; cd1j is the crop diversification index for the j th household. pij = proportion of total income from each crop in a particular enterprise. a value approaching 1.0 indicates specialization whereas smaller values reflect increasing diversification, stability of income and sustainability of land use pattern (spio, 1996; udoh, 2000). nutrient intake index (nii). following udoh (2000) the nii was estimated to reflect how crop diversity pattern can affect nutrient depletion and sustainability of farmland. this was measured as a ratio of crop configuration to number of crops in combination. crop configuration was derived by assigning different weights to different classes of crop in combination and summing the weighted value for each farm and then dividing the value by the number of crops in such combination. the assigned weights to the respective classes were based on nutrient depletion ability of crops in an environment where nutrient augmenting input like fertilizer is inadequate (fageria and baligar, 1993). it is expected that the yield of crops in combination would be affected if the combined crops were mostly of the same class of crops. for instance, a combination of melon/maize/yam would not deplete soil nutrient as the case of cassava/yam/cocoyam mixture. therefore, combining crops that would deplete soil nutrients heavily do not show sustainable land use practice. the nutrient intake index is given as niij = σwi i = (2 ----, n) n i = (2 ----, n) (2) where; niij = nutrient intake index for j th households. n = number of crop in combination wi = particular weight attached to type of class of crop planted (legume = 1, vegetable/cereal = 2, root tuber = 3, stem tuber = 4) lawal et al. 015 nutrient intake index is meant to capture the vulnerability of farm total output to different crop combination. the index value ranges between 1 and 4. the higher the nii the more the likelihood that crop combinations can affect nutrient depletion, land degradation and sustainability of farmland (fageria and baligar, 1993; ali, 1996; udoh, 2000). ruthenberg -value the ruthberg -value shows the land use intensity for an area. it shows if the length of fallow may be adequate for soils to restore natural fertility. it is given as; r – value = c c+f (3) where; c = number of cropping years. this was obtained as the average number of years a land was used before fallow. f = number of fallow years. this was obtained as average number of years a land was allowed to fallow before further cultivation. r – value = 1 for permanent cultivation. the further the value is from one the more the likelihood that fallow would be adequate to restore natural fertility and improve sustainability (udoh, 2000). degrees of soil erosion, flooding and drainage were also part of variables used to measure extent of likely land degradation, the level of nutrient depletion and fadama sustainability. farm budget model olukosi et al. (2006) stated that farm budget is a detailed physical and financial plan for operation of a farm for a certain period. farm budget model enables the estimation of the total expenses (costs) as well as various receipts (revenue or returns) within a production period. musa et al. (2006) stated that thectaret farm budget model gives a measure of profitability. following olukosi and erhectarebor (1988), farm budget was estimated on per hectare basis in this study and specified as nfi = gi tvc tf (4) gm = gi vc (5) where; nfi= net farm income, gm= gross margin per hectare. the fixed inputs used during the survey consist of inputs such as baskets, hoes, cutlasses and rain boot. the depreciated values of these assets were negligible, therefore gm/ha was used for profitability analysis. gm/ha was calculated for all the enterprises that the fadama farming households were engaged in during the survey period. gm allowed for comparison of the profit of the different enterprises cropped by the sampled households during the survey. return on a naira investment (rni) which provides a measure of economic performance of each enterprise in terms of revenue accruing to the households and cost of inputs employed was determined as; return on a naira investment (rni) = gi tvc (6) rni > 1 for enterprise to be sustainable (alamu and coker, 2005). return on a naira investment was used to rank the enterprises of the sampled fadama food crop farming household. results and discussion this section presents the results of the analysis of data collected and discussion on it. socio-economic characteristics of fadama food crops farm household heads table 1 shows the summary of farm inputs and socioeconomics characteristics of fadama food crop farming households during the 2004 cropping season. on the average the farm size cultivated was 3.44 ha in about 3 plots. hired labour was about 32% of total labour used for production. one of the probable reasons for hiring little labour could be the fact that an average fadama farming household head is still young (about 44 years), active and married with about 17 family members who provided the needed manpower for farm operations. on the average, the cost of labour used constitutes about 73.17% of total expenditure on farm inputs. this phenomenon clearly demonstrates the dominance of labour in food crop production in the fadama area. labour is the most important factor of production because farming activities in the area are mostly labour intensive. table 2 reveals that an average household head was about 44 years, males (97.32) and married (98%) with a household size of 17 persons. an appreciable high level of literacy was recorded among household heads (54%). they are likely to hectare good potentials to acquire and interpret messages relating to their farming operation. the mean fadama farming experience was about 17.5 years. about 59.06% of the sampled farming households hectared no extensions contact. the mean extension contact was 1.5 visits per household per annum. analysis of cropping pattern and index of diversity land use pattern the study reveals that the fadama farming household adopted different agricultural diversification strategies to fully utilize the fadama land and cope with risks and uncertainties. the strategies include: (i) an act of cultivating flood tolerant crop such as rice and sugarcane during the early wet season (ii) cultivation of drought resistant crops: millet, cowpea, sorghum, cassava later in the season at the drier part of fadama area. (iii) cultivation of crops with short gestation period: okra, leafy vegetable, late sorghum and cowpea to utilize moist land during the early part of dry season. these strategies assure adequate utilization of the fadama land, which satisfy the food security and income generation objectives of the households. tables 3 and 4 reveals that mixed cropping was the 016 afr. j. environ. econ. manage. table 1. summary statistics of farm inputs and socio-economic characteristics of average fadama food crop farming household. description sample mean standard deviation minimum value maximum value farm size (hectare) 3.44 2.68 0.10 6.30 number of plots 3.00 9.56 1.00 6.00 family labour (man-days) 118.74 38.99 7.00 220.00 hired labour (man-day) 55.71 11.63 2.00 70.00 family labour (n) 32,524.00 43.68 37.00 290.00 hired labour (n) 15,320.00 37.80 1750.00 55,000.00 total labour 47,845.00 218.54 50.00 17,500.00 pesticide (litres) 1.84 1.57 0.00 7.00 pesticide (n) 2,870.00 53.43 9250.00 72,500.00 capital (n) 2,275.00 9.53 0.00 12,000.00 fertilizer (kg) 78.00 2.76 0.00 8.00 fertilizer (n) 3,978.00 2.76 850.00 9,000.00 other operating cost (n) 6,624.00 204.30 0.00 38,500.00 age(years) 44..50 11.52 21.00 68.00 household size(no of people) 17.00 9.65 1.00 32.00 fadama farming experience(yrs) 17..50 8.65 6.00 45.00 extension contact (no of visits/yrs) 1.50 1.35 0.00 12.00 credit ( n) 3,250.00 192.40 0.00 35,500.00 * hired labour cost average n275 per man-day during the survey. source: field survey, (2004/2005) table 2. demographic characteristics of the fadama food crops farming household. characteristics frequency percentage (i) gender male 145 97.32 female 4 2.68 total 149 100.00 (ii) age group 20 50 125 83.89 >51 total 24 16.11 (iii) highest educational level 149 100.00 no formal education 17 11.41 quranic 54 34.89 adult 24 16.11 primary 43 28.86 secondary 9 6.04 tertiary 3 2.01 total 149 100.00 (iv) household size 1 5 15 10.07 6 10 27 18.12 11 15 42 28.18 16 20 51 34.23 21 25 9 6.04 > 26 5 3.36 table 2. contd. total 149 100.00 source of seed personal stock 88 59.06 local market 33 22.15 adp and other agencies. 28 18.79 total 149 100.00 (vi) experience in years 0 5 11 7.38 6 10 23 15.44 11 15 51 14.22 16 20 33 22.15 21 25 13 18.13 26 30 9 6.04 > 31 9 6.04 total 149 100.00 source of credit no credit 99 66.44 family and friend 30 20.13 money lenders 9 6.05 cooperative society 7 4.70 community bank 4 2.68 total 149 100.00 ii) no of extension visits. 0 88 59.06 1 2 22 14.76 3 5 18 12.08 6 8 16 10.74 9 11 > 12 5 3.36 total 149 100.00 source: field survey, (2004/2005) most common farming system. the sampled households cultivated thirteen (13) types of crops as sole enterprises and eleven (11) types of mixed crops enterprises during the survey. 209. 11 ha (36.70%) and 360.72 ha (63.30%) of the cultivated land area during the survey were used for sole crop enterprises and mixed crops enterprises respectively. results show that farming households use more of their own stock of local varieties, which inherently possess low yield potentials as planting material. rice is the dominant and most preferred crop planted as sole crop, it was the only crop planted by all the sampled households. it was planted in 17.14% (104.3 ha) of the land area utilized for crops production during the survey. maize/cowpea mixture was the most preferred enterprises among the mixed crop farms accounting for 10.36% (63.05 ha) of the total area cultivated by sampled households. the cropping pattern clearly reveals preference for rice, maize, sorghum, yam and cowpea as the most important food crops grown by the households. under crops combination, cowpea is the predominant second crop grown in association with cereal crop such as maize and sorghum. this result is similar to that of amaza (2000) which reported mixed cropping as the dominant cropping system of farmers in gombe state of nigeria. index of crop diversification the pattern of land use as regards stability of yield and revenue from crops planted are indicators of sustainable farm practice (webster, 1999). this is measured with the lawal et al. 017 018 afr. j. environ. econ. manage. table 3. distribution of area cultivated (ha) to sole crop enterprises. no of area cultivated % of area cultivated mean area minimum area maximu households (ha) cultivated (ha) cultivated (ha) cultivate cowpea 8 6.4 1.12 0.80 0.20 3.0 groundnut 8 16.00 2.81 2.00 0.50 2.5 maize 10 22.30 3.91 2.23 0.80 3.5 okra 12 7.20 1.26 0.60 0.20 2.0 onion 2 1.50 0.26 0.75 0.50 1.0 pepper 6 4.80 0.84 0.80 0.20 3.5 rice 149 104.3 18.32 0.70 0.30 4.5 sugarcane 7 5.6 0.98 0.80 0.30 3.0 sorghum 5 8.25 1.45 1.65 0.60 2.8 soybean 3 3.00 0.53 1.00 0.50 1.5 tomato 14 11.90 2.09 0.85 0.30 1.7 vegetables 14 12.46 2.19 0.89 0.25 1.0 yam 6 5.40 0.95 0.90 0.50 1.5 244 209.11 36. 70 0.86 source: field survey, (2004/2005). table 4. distribution of area cultivated (ha) to mixed crop enterprises. enterprise no of households area of land %of area of mean area minimum area ma cultivated (ha) land cultivated cropped(ha) cropped (ha) cr maize/sorghum 29 30.72 5. 39 1.28 0.20 mellon/maize/sorghum 28 46.94 8.24 1.68 1.0 maize/sorghum/cowpea 36 66.96 11.75 1.86 1.0 g/nut/sorghum/cowpea 12 16.80 2. 95 1.40 0.5 sorghum/cowpea 29 43.84 7. 69 1.56 0.2 sorghum/bambara 1 1.30 0. 23 1.30 1.30 maize/cowpea 58 71.34 12. 52 1.23 0.5 maize/cassava 10 8.64 1. 52 0.86 0.4 maize/yam 32 27.52 4.83 0.86 0.3 millet/groundnut 20 28.20 4. 95 1.41 1.0 millet/cowpea 13 18.46 3. 24 1.42 0.6 263 360.72 63.30 1.37 source: field survey, (2004/2005). table 5. herfidahl index of crop diversification description of cropping pattern mean herfidahl index sd minimum value maximum value cv % sole 1 1 1 1 100 two-crops combination 0.625 0.189 0.384 0.946 30 three-crops combination 0.462 0.106 0.264 0.753 23 whole farm 0.651 0.302 0.264 1 47 source: field survey, (2004/2005). indices of crop diversification. the index used in this study is herfidahl index. this is modeled in terms of proportion of net income from the various crops in each combination (see equation 1). table 5 shows that the estimated mean diversification index was 0.651. this implies increasing diversification among majority of fadama food crops farming households which could ensure stability of yield, income and sustainability of fadama land. these crop combinations could be regarded as environmentally and economically sound practice. it is environmentally friendly because when two or more crops are planted under low use of land augmenting material like fertilizers as observed during the survey, the negative effect of such material on the environment is reduced. the cultivated crop depended mostly on the available soil nutrient for their growth and development. each crop uses the fertility of the soil in its own peculiar way especially when the rooting systems of the crops differ. mixed cropping planted this way during the survey generally gives more revenue and higher gross margin per hectare than mono cropping. this finding is similar to the work of spio (1996); alamu and coker (2005) who reported thectaret mixed cropping in ghana and nigeria gave higher yields and revenue per hectare respectively. index of soil nutrient intake to achieve the maximum advantage of inter cropping or mixed cropping, combined crops must be grown in such a way that each crop in mixture uses the nutrient of the soil in different ways as to eliminate the risk of competition for the available soil nutrients. table 6 shows the distribution of the fadama farming households based on how their crop diversity pattern can affect nutrient depletion and sustainability of farmland. this was calculated using equation 2. the mean nutrient intake index (nii) was 1.89. this index measured the intensity of likely nutrient depletion by the combined crop. this result implies that the combined crops hectareve very low tendency to deplete soil nutrient. these may not be unconnected to the fact that eight (8) of the crop combinations hectared a leguminous crop in addition to the cereal in the combination. so the cropping pattern is such thectaret could not adversely affect soil nutrient and crop nutrition. these could trans table 6. distribution of nutrient intake index among sampled households. nutrient intake index frequency percentage 1 1.5 23 15.44 1.6 2.0 99 66.44 2.1 2.5 27 18.12 total 149 100 source: field survey, (2004/2005). these could translate to consistently good yield of fadama farm land which is an indication of sustainability of the cropping pattern of the fadama food crops farming households. udoh (2000) reported nii of 3.25 among farmers in eastern nigeria, most of these farmers planted root/tuber crops in combination with other crops. ruthbergvalue the ruthberg-value shows the land use intensity for the sampled households. it was estimated as 0.983 during the survey. this implies thectaret cultivation is nearly on a continuous basis in the fadama. these may not be unconnected with the high value attached to the fertility of fadama and probably the difficulty in land clearing. depending on the agronomic practices adopted by the households, the land use may be unsustainable. about 65% of the farms sampled hectared different levels of soil erosion symptoms indicating incidence of soil degradation and subsequent nutrient loss. the farmlands were not adequately covered with crop canopies. in the long run, without adequate remedial and preventive measures, soil fertility may be affected which could affect the sustainability of fadama land of niger state in nigerian southern guinea savanna. cost and returns in food crop production in fadama of southern guinea savanna of niger state, nigeria. from the results in table 7, the production cost and revenue per hectare varies across the households and it did not necessarily depend on the type of crop planted in the enterprises. gross margin analysis shows thectaret maize/cowpea enterprise with n25, 663/ha hectares the lawal et al. 019 020 afr. j. environ. econ. manage. table 7. gross margin per hectare by enterprises for food crops planted by sampled fadama farming households. enterprises mean farm mean variable gross margin ranked based return on revenue/ha cost per hectare per hectare on gm//ha naira investment r maize/cowpea 57,500 31,837 25,663 1st 1.81 sorghum/cowpea 40,100. 17,886 22,214 2nd 2.25 maize//sorghum/cowpea 42,700 22,122 20,578 3rd 1.85 maize / yam 56,250 36,684 19,566 4th 1.53 sugarcane 41,250 27,550 18,700 5th 1.68 sorghum / bambara 35,600 17,850 17,550 6th 1.89 millet /cowpea 36,400 19,750 16,650 7th 1.84 soybean 41,593 24,946 16,627 8th 1.57 g/nut / sorghum cowpea 39,700 23,283 16,417 9th 1.71 okra 28,850 12,502 15,950 10 th 2..30 mellon / maize /cowpea 36,585 20,670 15,915 11 th 1.73 maize / cassava 39,600 23,755 15,845 12 th 1.68 maize / sorghum 38,631 22,2716 15,684 13 th 1.61 rice 50,600 25,650 14,950 14 th 1.42 yam 34,200 19,461 14,739 15 th 1.76 pepper 32,487 18,195 14,292 16 th 1.79 sorghum 31,767 17,413 14,267 17 th 1..82 tomatoes 28,850 14,650 13,850 18 th 1..95 cowpea 31,500 17,685 13,815 19 th 1.78 millet /g/nut 28,300 14,595 13,705 20 th 1.94 vegetables 23,500 9,850 13,650 21 st 2.39 maize 29,592 16.250 13,342 22 nd 1.70 onion 21,600 14,000 7,660 23 rd 1.54 bambara 14412 8,461 5,951 24 th 1.70 whole farm 33, 623 18, 486 15, 137 1.89 source: field survey, (2004/2006). highest gm/ha during the survey. based on the profitability ratio leafy vegetable (spinach), okra and sorghum/cowpea ranked first, second and third respectively. these enterprises returns n2.39k, n2.30k and n2.25k on every n1 invested in the enterprises respectively. the average gross margin per hectare for a representative farm was n 15,137 while average net farm-income was conclusion n 52, 071. the average return on a naira invest ment ratio for all farms was 1.89 showing thecthe general co taret on financial consideration the farm operation that production of food crop farming households in the fadama of niger state, ni southern guinea savanna, niger state, nigeria crop enterprises was profitable and therefore sustainable. farm income, pr lawal et al. 021 investment ratio than is greater than one. the levels of diversification of the enterprises do not impact negatively on the nutrient intake index (nii) of the crops. the ruthberg index value, erosion and drainage situation shows thectaret remedial and preventive measure is required to ensure sustainability of fadama land in the southern guinea savanna of niger state, nigeria. recommendations government should provide adequate and assessable inputs such as work oxen, improve seeds, herbicides and fertilizers to fadama food crop farming households. the inputs should be provided at subsidized rate to encourage their usage. vigorous effort should also be made to encourage the farm households to employ animal traction involving oxen or camel with appropriate implements. the use of improved seeds varieties with high yield potentials together with packages of required crop husbandry is also recommended. extension workers should be properly motivated through provision of appropriate vehicle for their movement and prompt payment of their salary and allowances. the activities of the extension agents should also be monitored to ensure that they carried out their duty diligently. mixed cropping is recommended for food crop production in the fadama of southern guinea savanna niger state, nigeria. this would ensure stability of output and income. references adewumi mo, omotesho ao (2002). “an analysis of production objectives of small scale rural farming households in kwara state, nigeria” j. rural dev., 25: 201-211 alamu jf, coker aa (2005). “sustainability of fadama farming in northern nigeria. the case of kaduna state” samaru j. of agric. res., 21: 42-50. ali m (1996): “quantifying the socio-economic determinants of sustainable crop production an application to wheat cultivation in 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indicators” report prepared to oecd on agric. environmental indicator plenary session york street solow r (1992). “an almost practical step towards sustainability”. resour. policy 19: 162-172. spio kc (1996). “inter-cropping-the hidden revolution: a solution to land scarcity and household food security” in conference issue: paper presented at the 3 rd annual conference of the agricultural economic association of south africa, agrekon 35(4): 266 – 270 turner rk (1993). sustainable environment economics and management: principle and practice. london bell hectareven press tversky a, kahneman d (1981). “the framing of decision and psychology of choice” science 211: 453 458 udoh ej (2000). “land management and resource use efficiency among farmers in south eastern nigeria: ph.d thesis dept. of agricultural economics, university of ibadan. nigeria. vander hectaremsfort cpm, latacz-iohnman u (1998). “sustaina-bility. a review of the debate and an extension” int. j. sustain. dev. world ecol. 5: 1 12 webster p (1999). “the chectarellenge of sustainability at the farm level” j. agric. econ. 50: 371 – 387 world bank (1992). a survey of development of agriculture in subsahectareran africa and focus for world bank. the world bank, washington d.c usa. in ternationa l scholars journa ls african journal of environmental economics and management issn 2375-0707 vol. 4 (1), pp. 249-254, january, 2016. available online at www.internationalscholarsjournals.org © international scholars journals author(s) retain the copyright of this article. full length research paper eco-impacts evaluation in the greening approach adopted by the romanian public university andrew walker dunarea de jos university, domneasca, 47, 800008 galati, romania. email: andrew_walker@yahoo.com. accepted 04 october, 2015 the present paper compared the results generated from 2 eco-indicators (ecological footprint and carbon footprint) as important markers in future greening strategy evaluation that will be adopted for the first time by a romanian eastern public university (ugal). the calculated amount of ef value per students is 0.818 gha and per capita is 0.760 gha. the eco-indicators values are more reasonable in compare with the recommended amount by the wwf (the average is 1.9 gha per capita) and also with the values which are reported by the other universities. energy, transportation systems and foods are the most important portions of the total ef value. keywords: eco-indicators, ecological footprint , carbon footprint, higher education. introduction the real world is moving towards a severe limitation of resources. energies resource, essential resources for human well-being, which are approaching to their peak point. human demand on ecosystem services continues to increase without a correlation with the regenerative and absorptive capacity of the biosphere. the natural capital may increasingly become a limiting factor for the future human demand. humanity is posed in front of a major nature transformation and to face serious environmental challenges at global and local scales. the ecological attitude and sustainable behaviour has become a necessity in the recent decades (chambers et al, 2000). the ecological footprint measure the natural capital demand of human activities (wackernagel and rees, 1996) and reveal the sustainability of consumption patterns on individual, local, national and global scales (arrow et al, 2002). ecological footprint model assumes that all types of energy, material consumption and waste discharge require productive or absorptive capacity of a finite area. six types of ecological biologically productive area (arable land, pasture, forest, sea space, built-up land and fossil energy land) are used to calculate the ecological footprint and ecological capacity (wackernagel et al, 2002). the ecological footprint estimates the „„minimum land necessary to provide the basic energy and material flows required by the economy‟‟ (wackernagel and rees, 1996). the consumption elements are converted into a single index: the land area to sustain the life living among human consummation groups. the area of land or sea available to serve a particular use is called biological capacity (bio-capacity) and represents the biosphere‟s ability to meet human demand for material consumption and waste disposal. the degree of non-sustainability is calculated as the difference between actual available and required land. in the original ecological footprints model created by wackernagel and rees (1996) and reformulated by chambers et al. (2000), the land areas included were mainly those directly required by households with self-consummation life style. in the original ecological footprint model, land categories are weighted with equivalence and local yield factors, in order to express appropriated bio-productivity in world-average terms (wackernagel et al, 2002). in the original ecological footprint method, only emissions of co2 from energy use were considered without the influence of greenhouse gases, land clearing, and enteric fermentation in livestock, industrial processes, waste, coal seams, venting and leakage walker 250 table 1. general inputs for the ugal eco-indicators assessment element value ugal total students 18000 full time students 10000 part-time students 8000 ugal total employees 1358 in-campus students 3400 average total menus served per day 400 active weeks per academic year 45 total menus served per academic year 82000 snack menus served per academic year 4100 lunch semi-complete menus served per 41000 academic year lunch complete menus served per academic year 4100 dinner menus served per academic year 32800 of natural gas. since the formulation of the ecological footprint, a number of researchers have criticized the method as originally proposed (arrow, et al 2002; costanza, 2000). in nowadays, the eu caterers are concerned about the environmental and sustainability issues, including the provenance and production methods of procured food, waste management, energy and water consumption (dawe et al, 2004). universities are public institutions that move to become more sustainable. new ways to measure progress are being sought such as carbon footprint analysis (cfa) and ecological footprint analysis (efa). many universities have adopted broad environmental responsibility and/or sustainability policies (van den bergh and grazi, 2010). all the public universities have a particular social responsibility in encouraging best environmental practice, due to their considerable influence on societal development (wackernagel, 1991). a number of campuses have published efa assessment results (burgess and lai, 2006; conway et al, 2008; dawe et al, 2004; flint, 2001; li et al, 2008; venetoulis, 2001; wright, 2002) but only two studies regarding a large public university (janis, 2007; kleinbanai et al, 2010). a comprehensive and consistent comparative study of efa versus cfa results for a eastern public university is not available in the scientific literature. the objective of the present research is to evaluate the actual eco-impact of ugal activities by using the efa and cfa methodology. in the medium term, ugal intention is to promote a sustainable green policy with the following major objectives: 1. decreasing the material (foods, packages, utilities etc.) and energetic waves as daily activities inputs; 2. improvement of the air quality; 3. improvement of the energetic quality performance and green energy production; 4. improvement of the water management system; 5 . improvement of the green facilities management. the present research compare the results generated by 2 eco-indicators (ecological footprint and carbon footprint) as important markers in the evaluation of future greening strategy that will be adopted for the first time by a eastern public university from romania (ugal). materials and methods the data involved in the eco-indicators assessment were obtained directly from the ugal campus and general administrative management office. the ugal campus population in 2010 consisted of 10.000 full-time students, 8000 part-time students and 1358 employed staff. the total ugal facilities area is in average 11gha and the building area is about 5.4 gha. the efa methodology was based on wackernagel and rees procedure (1996). in the calculation of specific ef we take into account all the quality-controlled life cycle information including energy, materials, transportation and wastes. in order to calculate ef, the inputs of different kinds are first converted to the corresponding actual area of land/water ecosystems needed to produce the resources or assimilate the emissions. the efa results were expressed as units of ef in global hectare with world average biological productivity, for the purposes of adding areas together and comparing results across land types. the cfa is based on the calculation of cf for materials and processes with known quantity of fuel, energy or raw material multiplied by a conversion factor, which is a rate of tons of co2e emitted per quantity of the material consumed (defra, 2009). greenhouse gases emitted through transport and the production of food, energy, utilities (electricity, gas, coal, water) for university activities and services are expressed in terms of the amount of co2e emitted, in tonnes units. the methodology is highly compatible with iso 14042 requirements. both methodologies generate the information and data necessary for the eco-indicators assessment by analyzing and quantifying the flows of all resources (inputs) and produced waste (outputs) on the campus (canteen and student‟s residence) and in all ugal facilities. the input data for the eco-indicators assessment were presented in table1, table 2.1, table 2.2 and table 3. results and discussions the results of efa include the basic lifecycle data for food consummation, energy demand, food wastes and transportation (table 4). the results of cfa include the basic lifecycle data for food consummation, energy demand, food wastes and transportation (table 5). table 2 .1. utilities consummation in ugal table 3.commodities consummation in ugal canteen utility item consummation no,the units are commodities item consummation, specified in the utility line (t/year) electricity, mwh 1423 gas, m3 175313 water, m3 72808.76 coal, gcal 5557.08 car traffic, km 29588 table 2 .2. wastes collected in ugal beef meat 0.626 pork meat 2.906 poultry 5.337 fish 0.089 vegetables 19.568 pulses, flavourings 0.436 eggs 0.602 wastes categories total quantities (kg/year) domestic waste 5291.81 food wastes 419.26 garden wastes 2439.76 paper ,packages waste 636.84 plastic waste 538.52 glass waste 646.18 total 9972.37 total per employee 7.34 table 5. ugal carbon footprint assessment component cf, tco2eq energy 1358.451 electricity 1148.361 gas 143.406 coal 66.684 water 0.80 wastes 3.3 transport 5177.9 small traffic (175 g/km) 5177.9 commodities 43.722 beef meat 8.951 pork meat 11.04 poultry 5.870 fish 0.039 vegetables 4.500 pulses 0,109 eggs 6.000 milk 0.272 cream 0.846 cheese 0.521 pasta 0.599 rice 0.103 sugar 0.081 vegetable oils 3.601 flours 0.317 cereals 0.873 total cf, ugal 2010 6584.173 cf per students 0.365 cf per capita 0.340 milk 1.362 cream 0.423 cheese 0.372 pasta 0.403 rice 0.648 sugar 0.090 vegetable oils 3.274 flours 0.357 cereals 1.468 total 35.862 table 4. ugal ecological footprint assessment component ef, gha energy 12301.674 electricity 1302.045 gas 5953.629 coal 5046 water 380.425 wastes 3.025 transport 1479.4 traffic car 1479.4 commodities (foodprint) 559.565 beef meat 76.24 pork meat 123.79 poultry 217.216 fish 1.424 vegetables 82.186 pulses, flavourings 2.341 eggs 9.933 milk 2.64 cream 8.164 cheese 5.743 pasta 10.075 rice 1.944 sugar 4.869 vegetable oils 130.96 flours 7.854 cereals 15.854 ef ugal 2010 14724.089 ef per student 0.818 ef per capita 0.760 ecological foodprint per in campus 0.016 students ecological foodprint per student which 1.39 serve the meal in the campus area 251 afr. j. environ. econ. manage. the calculated ef value per students is 0.818 gha and per capita 0.760 gha. the eco-indicators values are reasonable in compare with the wwf recommendation (average of 1.9 gha per capita) and the values reported by the other universities (table 6). energy, transports and foods are the most important parts of the total ef value. in the food processing department, vegetables, poultry, beef and vegetable oils have the greatest ratio in the total ef due to the greatest amount in the daily canteen use. in fact, only beef induce the leading impact on the total agro-foods ef and cf, respectively. vegetables, milk, fruits and cereals have the lower value of ef and the ratio proposed in the optimized eco-menus must be the increased in order to generate a significant reducing of the total ef. the poultry items present the lowest ecological and emissive impact, in average with 3 times less than beef items. regular use of low-carbon fish (mackerel, herring) could reduce substantially the meal‟s average carbon footprint. the food commodities created by an intensive processing such refining (oils, sugar), dry substance concentration (cream, cheese, pasta, cans) or extraction (flour) multiply the ef value of the raw material with the number of concentration /extraction degree. this is a strong reason for avoid the large quantities of industrialized foods, herbs, eggs and red meats and valorise the raw, unprocessed and fresh local/traditional products as input in the canteen production. in terms of gas emissive effect, the ec per student is calculated at 0.365 tco2eq/ year and ec per capita is 0.340 tco2eq/ year. the electricity represent 84.5% from total emission generated by all forms of energy used in ugal facilities and the transportation system cover 78.64% from total cf. food commodities have a minor impact on the total cf (0.066%) and the undercollected wastes (7.34 kg/year, employees) represent an insignifiant part (0.005%, 3.025 ef units per year). in the food processing department the pork items are environmentally more favourable than chicken and the chicken items are more environmentally favourable than lamb and beef. beef is found to be around four times more co2emissions intense than pork meat. the comparative results of the present research and the prior studies conducted in other campuses and universities are presented in table 6. the results are very much similar with the others presented in the previsious works, in terms of ef per capita and ratio of the principal ugal ef elements (energy 83%, transport 10%, water 2.5%, food 3.8%, wastes 0.02%) from the total ef value. the proportion of the energy module is overload because of the traditional technologies involved in the general management and the ratio of food is underload because only 11.7% of the total ugal in-campus students eat in the canteen facilities every day. conclusions both ef and cf represent efficient and consistent tools to measure sustainable development by comparing communities‟ consumption of natural resources and the corresponding bio-capacity. the principal conclusions of the eco-indicators assessment are as followings: -the energy consummation for food processing is in average 3.967mwh/t, 10% from total energy consumed in ugal; -meats commodities are the greatest emissive items involved in the daily menus and the potential environmental damage is estimated at 74.56% from the total foods ef (foodprint value); -the primary agricultural products present the lowest ef value; in contrast, a greater industrialisation food degree due to a proportionally increasing of foodprint value (in case of refined foods as oils, sugar or food derivates such as cream butter or cheese); -as a general rule, the degree of the principal compound from the dry substance concentrated in the industrialisation process represent the factor of multiplying the ef value of the raw food; -the average wastes generated in a day is 0.036t and in average the ratio food/food wastes is 3.59/1; -the smallest impact on both gas emissive effect (cf) an ef value is generated by the wastes 0,02% from total ef, followed by water 2.5% and food 3.8%. as a general rule, the choice of raw materials has a considerable impact on greenhouse emissions. walker 252 . table 6. comparison of ef for colleges and universities university dunarea de university university of holme lacy college, northeastern university of colorado kwantlen ohio state jos university of illinois at toronto at university university newcastle uk university, china college galati (ugal) chicago mississauga college columbus year 2010 2008 1999 2001 2003 2005 2006 2006 2007 ef ,gha 14724.08 97601 3592 296 24787 8744 5603 3039 650,666 ratio ef to 897.81 1005 26 1.23 50 97 154 81 916 land area ef per 0.76 2.66 0.19 0.57 1.06 1.07 2.24 0.33 8.66 capita energy,% 83 72.66 47 19 67.97 69.40 87 28.90 23.30 transport,% 10 12.60 46 23 0.08 16.10 1.40 53 72.24 materials and 0.02 11.83 2 32 5.74 4 na na 4.46 waste,% paper,% na na na na 2 na na 7.20 na food,% 3.8 2.60 2 25 21.80 9.20 10 9.60 na built-up na 0.18 2 1% 0.44 1.20 na 1.10 w/transport land,% water,% 0.02 0.14% 1 w/built-up land 2 0.20 1 0.16 na source: vintila, 2011: venetoulis,2001: flint, 2001: dawe et al.,2004: li et al.,2008: conway et al.,2004: wright 2002: burgess and lai,2006: janis,2007 different food ingredients such as low-carbon fish and meats can reduce substantially a meal‟s average foodprint recommandations the future ugal greening strategy include following recommendation based on the present research results: 1.reducing under 50% in the next 5 years the amount of food items with greatest energetically metabolism: meats, especially beef and refined foods as sugar, spices, coffee, oils, butter, cream, cheese. 2. replacing animal origin protein commodities with vegetable protein sources once or twice in a week in the next 5 years; 3. increase with 30% the number of meals served in ugal canteen in the next 5 years; 4. replacing 50% of the actual imported commodities with local sources of fresh and brute, unprocessed agro-foods in ugal canteen in the next 5 years; 5. moderate the thermal treatments of food products in order to reduce the energy involved in food processing; 6. selected food equipments with optimal energy consummation related with the productivity and reduce the surface of the foodservice area in order to reduce the utilities consummation; 7. increase the amount of collected wastes and the recycled wastes ratio, especially in case of glass, plastic and paper ; 8. gradually replacing the actual car park used for internal transport with less emissive eco car model ( emission under 120g/km); 9. replacing 5% of the actual conventional fuels with agro-carburant in the next 3 years and with 10% in the future 5 years; 10.increase the amount of renewable energy resources and energy saving equipments; 11.promote a eco-conscience for all university 253 afr. j. environ. econ. manage. walker 254 staff (eco behaviour courses included in the general curricula), important part of the eco-citizen attitude in nowadaysworld. perspectives actual statistics discuss about the resources limitation in the near future in which the eco-management became a necessity in order to respect the regional biocapacity. the sustainable green policy is based on the direct relation existing between the quality of the environment and the health status of the students, professors as well as administrative &technical university staff. “greening” the public universities is a social responsibility which must be imposed by the academic media and involve the development of a more sustainable resources using, transportation systems as well as the reduction of on-campus consumption. the model for the eco-indicators assessment of ugal in 2010 will be proposed as a base of an eco-strategy constructed in order to reduce the actual ef on the individual, institutional and national scale. acknowledgement the author would like to thank the ugal rector prof.minzu viorel, ugal general administration head ms.narcisa condrea,ugal canteen administration head mr.bichescu cezar and his collaborator ms.onofrei nicoleta.further,the author would to extend a special thank you to all the collaborators from agrobio 35 mr.jaffre, conseil regional de bretagne ms. rouger, manger bio35 mr.gabillard, association solidarite 35 mr.venien and ms.sinequin, scarabee biocoop mr.chevalier, frcivam mr.marechal, inter bio 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online at www.internationalscholarsjournals.org © international scholars journals author(s) retain the copyright of this article. full length research paper a study of the heavy metals and their level in the solid and liquid waste in uttarakhand state of india sanjeev ajit1, mishra naqvi1 and vinay maneka2 1 college of renewable energy & environmental engineering, sardarkrushinagar dantiwada agricultural university, palanpur, gujarat, india. 2 centre for environmental planning and technology university, ahmedabad, gujarat, india. accepted 12 november, 2016 the aim of this study was to estimate the heavy metals and their level in the solid and liquid (municipality waste and industrial effluent) waste in uttarakhand state of india. it is the part of my research on in situ bioremediation. 62 samples from 32 cities of uttarakhand were collected according to standard method of apha in triplicate. the heavy metals viz. zinc (zn), manganese (mn), nickel (ni), copper (cu), chromium (cr), cadmium (cd), lead (pb) and cobalt (co) were reported in the waste samples. mercury and arsenic were not detected in any set of sample. the metal zinc was measured in maximum extent in all the samples. the metals zn, mg, ni, cu, cr, cd, pb and co were measured minimum 0.45mg/l, 0.28mg/l, 0.021mg/l, 0.005mg/l, 0.018mg/l, 0.001mg/l and 0.002mg/l and maximum 11.9mg/l, 55.5 mg/l, 7.6 mg/l, 6.503 mg/l, 8.56 mg/l, 8.56 mg/l, 8.56 mg/l and 0.905 mg/l respectively. the heavy metals in waste can pose serious health problems in human also. it is recommended that periodic analytical testing of heavy metal should be carried out for maximum permissible level. primary treatment is required for the quality of the waste/effluent. keywords: heavy metal toxicity, icp-ms, e-waste, effluents, permissible limit. introduction the waste contaminates the soil. the solid waste includes garbage, domestic refuse and discarded solid materials such as those from commercial, industrial and agricultural operations. they contain increasing amounts of paper, cardboards, plastics, glass, old construction material, packaging material and toxic or otherwise hazardous substances (knaebel et al., 1994). the ewaste contains some very serious contaminants such as lead, cadmium, beryllium and brominates flame retardants (dogbevi, 2007; pinto 2009). liquid waste, wastewater, fats, oils or grease or used oil have various contaminants including soil particles and other sediment, heavy metals, organic compounds, animal waste. it may be originated from various sites and by different uses (massoud and ahmad 2005). industrial wastes will be as varied as the industries that generate the wastes. municipal waste-water also contains a variety of inorganic substances from domestic and industrial sources, including a number of potentially toxic elements such as arsenic, cadmium, chromium, copper, lead, mercury, zinc etc (ferrari et al., 1999). some human activities have resulted in the accumulation of metals in the environment. both soil and aqueous effluents have been contaminated with heavy metals as the result of numerous industrial activities, including mining, smelting, jewellery, automobile battery production, vehicle emission and landfilling of industrial waste and fly ash from incineration process. this contamination of the environment poses serious health threats to humans and animals, as these heavy metals tend to persist in the environment indefinitely. this kind of contamination presents a challenge, as the presence of heavy metals in soils and aqueous effluents leads to serious problems because they cannot be biodegraded. in this case, the metal ion can only be converted to the base metal, methylated, precipitated, corresponding author. email: sanjeev.ajit@yahoo.com ajit et al. 278 figure 1. location of uttarakhand volatilized or complexed with an organic ligand. the development of technologies involving many of the processes listed above has been the subject of a host of basic and more applied projects. the more common heavy metals (hms) associated with anthropogenic activities include lead, cadmium, copper, chromium, nickel, iron, mercury and zinc. methods of treating the contaminated effluents currently consist of chemical precipitation, solvent extraction, dialysis, electrolytic extraction, cementation, reverse osmosis, evaporative methods, ion-exchange resins, carbon adsorption and dilution (european union, 2002). several metals are essential for biological systems and must be present in a certain concentration range. too low concentrations lead to a decrease in metabolic activity. at too high concentrations these metals lead to toxicity. nonessential metals are tolerated at very low concentrations and inhibit metabolic activity at higher concentrations. the many uses of heavy metals in several applications lead to their wide distribution in soil, silt, waste and waste water. such pollution of the environment by toxic metals and radionuclide arises as a result of many human activities, largely industrial, although such sources as agriculture and sewage disposal also contribute. heavy metal contamination can be a consequence of industrial activities that eliminate residues in the soil that in long term promote their accumulation. the majority of the sources are originated by human actions like metal manufacture and mining industries with storage, disposal and transportation problems (glick, 2003). among the metals found more frequently there are cd, pb, co, cu, hg, ni, si and zn. for cd, pb, cu and zn, their toxicity increases as follows: pb < zn < cu < cd, depending on countless abiotic and biotic factors (zenker et al., 2005). the discharge of wastewater containing high concentrations of heavy metals to receiving water bodies has serious adverse environmental effects. their occurrence and accumulation in the environment is a result of direct or indirect human activities, such as rapid industrialization, urbanization and anthropogenic sources (epa, 1998; 2000; hussein et al., 2005; gardea et al., 2005). metals when present in our body are capable of causing serious health problems, by interfering with, our normal body functions. some of these metals are useful to the body in low concentrations like arsenic, copper, iron and nickel but are toxic at high concentrations. other metals like aluminum, beryllium, cadmium, lead and mercury have no biological functions and are highly toxic disrupting bodily functions to a large extent. they disrupt bodily functions by accumulating in vital organs and glands in the human body such as in the heart, brain, kidney, bone and liver. they also displace vital nutritional minerals from their proper place in the body to provide biological functions e.g., lead or cadmium displaces calcium in an enzyme reaction disrupting the enzyme reaction to a large extent (european union, 2002). cr (vi) is toxic, carcinogenic and mutagenic to animals as well as humans and is associated with decreased plant growth and changes in plant morphology. they cause physical discomforts, diseases and disorders and sometimes life threatening illness including irreversible damage to vital body system (malik, 2004; ozer and pirincci, 2006). materials and methods sampling sites and sample collection the solid and liquid wastes were collected from 32 different sites of uttarakhand (figure 1) especially from municipality and industrial area. the sites were identified for sample collection and given a definite code (table 1). the method of sample (solid and liquid waste) collection was followed of apha 1998. the solid waste samples were collected in polythene bags of capacity 1 kg and carried to laboratory in well packed box sealed in ice to avoid the contamination. the area covered 1 m 2 in depth of 25 cm. the liquid wastes was collected in pre-rinsed table 1. name of sampling site with code. s.no. sampling site code s.no. sampling site code 1 pauri pa 17 joshimath jm 2 lansdown ld 18 ukhimath um 3 kotdwara kd 19 srinagar sn 4 rudraprayag rg 20 uttarkhashi uk 5 devprayag dp 21 purola pl 6 almora am 22 mussorie mr 7 lohaghat lg 23 dhanolti dn 8 ranikhet rt 24 chamba cb 9 nainital nl 25 new tehri nt 10 haldwani hd 26 badshahithaul bt 11 pantnagar pn 27 chakrata cr 12 rudrapur rp 28 dakpathar dk 13 tanakpur tp 29 dehradun dd 14 kashipur kr 30 haridwar hr 15 corbett national park cp 31 rishikesh rk 16 roorkee rr 32 lakshar ls clean one liter polythene bottle having double stopper facility to its full capacity without entrapping air bubbles inside it. preparation of leachate the leachate from solid waste was prepared according to the method described by french standard method (ferrari et al., 1999, srivastava et al., 2005 and savitha et al., 2010). for leachate preparation; 100 g of solid waste was added to 1000 ml of distilled water, which was kept on a rotary shaker at 180 rpm at 30 ±1 0 c for 24 hr for continuous shaking. the suspension was first course filtered muslin cloth and then by whatman filters paper no. 42. to remove the fine suspended particles, it was centrifuged at 3000 rpm for 15 min and the supernatant was used for heavy metal analysis. heavy metal analysis the filtrate of solid and liquid waste was used to analyze the heavy metal concentrations by inductive coupled plasma-mass spectroscopy (icp-ms) using ar grade chemicals and high grade reference (ashok et al., 2010). analysis of data the data (tables 2,3,4,6) were statistically analyzed by using one way analysis of variance (anova) at p = 0.05 (snedecor and cochran 1982; sas 2001). all statistical analyses were performed with statistical analysis system programs spss 10.0 for windows 2003 xp. results the eight metals viz. zinc (zn), manganese (mn), nickel (ni), copper (cu), chromium (cr), cadmium (cd), lead (pb) and cobalt (co) were measured in the solid and liquid waste. mercury (hg) and arsenic (as) were not detected in any set of sample. zinc found in high extent among the samples analyzed although it was nil in 19 samples i.e. 15 solid samples pa, rg, nl, pn, rp, cp, um, sn, uk, pl, dn, cb, nt, bt, ls and 4 liquid samples lg, jm, pl and cr. zinc was recorded minimum (0.45mg/l) at almora (solid) and maximum (11.9mg/l) at roorkee (liquid). manganese was nil in 25 samples i.e. 11 solid samples rg, am, rt, pn, rp, tp, cp, um, sn, dn, ls and 14 liquid samplesld, am, lg, rt, hd, pn, rp, cp, jm, um, uk, pl, dn and cr. manganese was minimum (0.28mg/l) at purola (solid) and maximum (55.5 mg/l) at kashipur (liquid). nickel found nil in 33 samples i.e. 5 solid samples of am, tp, jm, cr, rr and 26 liquid samples of pa, ld, kd, rg, dp, am, rt, nl, rp, cp, jm, um, sn, uk, pl, mr, cb, nt, bt, cr, dk, dd, hr, rk and ls. ni was minimum (0.021mg/l) at danolti (solid) and maximum (7.6 mg/l) at musoorie (solid). the copper was not detected in the 32 samples (26 solid samples of pa, ld, kd, rg, dp, nl, hd, pn, tp, kr, cp, jm, um, sn, uk, pl, mr, cb, nt, bt, dk, dd, hr, rh, ls and rr and 6 liquid samples of lg, rp, tp, kr, cp and dk). copper was minimum (0.005mg/l) at dhanolti (liquid) and maximum (6.503 mg/l) lansdwon (liquid). chromium found nil in 26 samples i.e. 12 solid samples of ld, rt, nl, tp, cp, jm, sn, uk, pl, cb, nt, bt and 14 liquid samples of ld, rg, dp, am, lg, nl, rp, um, uk, pl, dn, nt, dk and rr. chromium was minimum (0.018mg/l) at lakshar (solid) and maximum (8.56 mg/l) at haridwar (liquid). 279 afr. j. environ. econ. manage. table 2. total metals analysis in solid and liquid wastes (mg/l) s. no city waste zn mn ni cu cr cd pb hg co as 1 pa solid nil 12.50 0.85 nil 0.09 nil nil nil 0.230 nil liquid 4.560 15.90 nil 1.09 0.03 0.007 0.830 nil nil nil 2 ld solid 4.905 3.678 0.875 nil nil 0.215 nil nil 0.35 nil liquid 5.680 nil nil 6.503 nil 2.380 nil nil nil nil 3 kd solid 6.458 11.90 5.95 nil 0.45 nil nil nil 0.430 nil liquid 5.435 12.40 nil 3.78 0.76 0.100 0.322 nil nil nil 4 rg solid nil nil 6.50 nil 0.32 nil nil nil 0.450 nil liquid 4.550 9.87 nil 1.65 nil 0.012 0.025 nil nil nil 5 dp solid 3.455 4.58 3.30 nil 0.05 nil nil nil 0.230 nil liquid 4.350 8.90 nil 0.79 nil 0.015 0.054 nil nil nil 6 am solid 4.567 nil nil 0.452 3.456 0.005 nil nil nil nil liquid 0.45 nil nil 0.580 nil 0.086 0.02 nil nil nil 7 lg solid 2.505 1.560 2.456 0.580 0.450 nil nil nil nil nil liquid nil nil 2.350 nil nil nil 0.568 nil nil nil 8 rt solid 5.89 nil 0.785 3.568 nil nil 0.05 nil nil nil liquid 2.36 nil nil 1.456 0.067 0.043 nil nil nil nil 9 nl solid nil 9.50 1.29 nil nil nil nil nil 0.089 nil liquid 2.320 4.60 nil 0.110 nil 0.008 0.010 nil nil nil 10 hd solid 2.305 5.45 1.95 nil 0.560 nil nil nil 0.087 nil liquid 4.550 nil nil 0.320 0.870 0.010 0.120 nil nil nil 11 pn solid nil nil 0.345 nil 2.650 nil 0.785 nil nil nil liquid 8.905 nil 0.125 0.645 0.128 0.760 nil nil 0.50 nil 12 rp solid nil nil 2.872 0.325 0.785 nil 0.896 nil nil nil liquid 4.680 nil nil nil nil nil 0.325 nil nil nil 13 tp solid 4.580 nil nil nil nil 0.234 0.456 nil nil nil liquid 2.456 3.245 3.456 nil 0.981 0.680 nil nil nil nil 14 kr solid 5.860 35.50 6.50 nil 3.12 nil nil nil 0.205 nil liquid 8.780 55.50 1.35 nil 2.15 0.605 0.564 nil 0.260 nil 15 cp solid nil nil 0.654 nil nil nil 0.765 nil 0.25 nil liquid 4.891 nil nil nil 6.40 0.505 nil nil nil nil 16 jm solid 6.780 2.543 nil nil nil nil nil nil nil nil liquid nil nil nil 0.783 0.532 0.543 0.543 nil nil nil 17 um solid nil nil 4.50 nil 0.32 nil nil nil nil nil liquid 4.550 nil nil 1.05 nil 0.015 0.035 nil 0.350 nil 18 sn solid nil nil 0.78 nil nil nil nil nil 0.120 nil liquid 6.980 10.65 nil 0.45 0.07 0.002 0.230 nil nil nil 19 uk solid nil 0.980 0.03 nil nil nil nil nil 0.002 nil liquid 3.120 nil nil 0.065 nil 0.003 0.013 nil nil nil 20 pl solid nil 0.280 0.033 nil nil nil nil nil 0.002 nil liquid nil nil nil 0.065 nil 0.003 nil nil nil nil 21 mr solid 8.455 12.97 7.60 nil 0.56 nil nil nil 0.905 nil liquid 8.120 34.80 nil 5.95 1.05 0.210 0.202 nil nil nil 22 dn solid nil nil 0.021 0.052 0.050 nil 0.003 nil nil nil liquid 1.68 nil 0.022 0.005 nil nil nil nil nil nil 23 cb solid nil 3.60 0.40 nil nil nil nil nil 0.079 nil liquid 6.840 6.50 nil 0.89 0.098 0.003 0.101 nil nil nil 24 nt solid nil 1.50 0.06 nil nil nil nil nil 0.045 nil liquid 5.989 7.80 nil 0.015 nil 0.001 0.010 nil nil nil 25 bt solid nil 8.95 0.76 nil nil nil nil nil 0.040 nil liquid 0.760 4.76 nil 2.08 0.054 0.004 0.150 nil nil nil 26 cr solid 0.890 5.560 nil 1.65 1.98 nil nil nil nil nil liquid nil nil nil 2.087 0.98 2.56 nil nil nil nil 27 dk solid 3.257 11.85 2.58 nil 0.605 nil nil nil nil nil liquid 5.505 8.85 nil nil nil 0.012 0.025 nil nil nil 28 dd solid 7.908 30.20 5.50 nil 3.34 nil nil nil 0.605 nil liquid 9.980 45.75 nil 4.78 1.85 0.405 0.560 nil nil nil 29 hr solid 7.830 10.90 5.30 nil 2.09 nil nil nil 0.550 nil liquid 8.227 20.50 nil 3.90 8.56 0.523 0.858 nil nil nil 30 rk solid 7.980 11.45 2.60 nil 0.96 nil nil nil 0.420 nil liquid 8.500 13.67 nil 1.80 1.45 0.020 0.865 nil nil nil ajit et al. 280 table 2. cont. 31 ls solid nil nil 0.65 nil 0.018 nil nil nil 0.076 nil liquid 3.450 3.07 nil 0.078 0.020 0.005 0.011 nil nil nil 32 rr solid 8.90 20.55 nil nil 3.45 nil nil nil nil nil liquid 11.9 45.75 5.30 4.78 nil 0.405 0.56 nil 0.15 nil *leachate was used to test. #data depicted in the table is the average of three samples. cadmium found not measured in 32 samples i.e. 29 solid samples of pa, kd, rg, dp, lg, rt, nl, hd, pn, rp, kr, cp, jm, sn, uk, pl, mr, dn, cb, nt, bt, cr, dk, dd, hr, rh, ls, rr cities and 3 liquid samples of lg, rp and dn. cadmium was minimum (0.001mg/l) at new tehri (liquid) and maximum (8.56 mg/l) at chakrata (liquid). lead was found nil in 35 samples (26 solid samples of pa, ld, kd, rg, dp, am, lg, nl, hd, kr, jm, um, sn, uk, pl, mr, cb, nt, bt, cr, dk, dd, hr, rh, ls, rr and 9 liquid samples of ld, rt, pn, tp, cp, pl, dn, cr). lead was recorded minimum (0.003mg/l) at dhanolti (solid) and maximum (8.56 mg/l) at rudrapur (solid). cobalt was nil in 40 samples i.e. 12 solid and 28 liquid out of 64 samples. cobalt was measured minimum (0.002mg/l) uk (solid) and maximum (0.905 mg/l) mr (solid). the total metal analysis was done for river water and it was found that water sample of yy had no metals although zn was found in all water samples except bg, mr and yy. copper (cu) was detected in alaknanda at rudraprayag (0.52mg/l) and yamuna at dakpathar (0.004mg/l) only. cadmium (cd) was found in ganga at hardwar (0.012mg/l) and yamuna at dakpathar (0.011mg/l), nickel (ni) in ganga at hardwar (0.01mg/l) and lead (pb) in ganga at hardwar (0.08mg/l) and yamuna at dakpathar (0.53mg/l). mn, hg, co and as were not detected in any sample (table 2). discussion the elements viz. zn, mn, ni, cu, cr, cd, pb and co were observed in the waste samples. according to icmr (1996) the zinc is an essential element in human metabolism. it changes the verge taste at about 5 mg/l and imparts caustic taste to water. manganese is essential as a cofactor in enzyme systems and metabolism processes. it is reported (icmr, 1996; who, 2001) that the excess of mn causes change in appetite and reduction in metabolism of iron to form hemoglobin. it imparts undesirable taste and stains plumbing fixtures and laundry. the nickel observed 0.021 mg/l to 7.6 mg/l in the waste samples, whereas the desirable limit is 0.20 mg/l for crop production, it reduced toxicity at neutral or alkaline ph (pratt, 1972). the short-term overexposure to nickel (usepa, 2000) is not known to cause any health problems, but long-term exposure can cause decreased body weight, heart and liver damage and skin irritation. the epa does not currently regulate nickel levels in drinking water. nickel can accumulate in aquatic life, but its presence is not magnified along food chains (usepa, 2000). the copper was observed 0.005mg/l 6.503 mg/l which exceeded the permissible limit for crop production and is toxic to a number of plants (pratt, 1972). copper in the natural water also results in higher concentration due to pollution. according to icmr, (1996) it imparts biting taste but essential element in human metabolism. the deficiency of cu results in nutritional anemia in infants and large amount of cu may result in liver damage, cause cns irritation and depression. the chromium was found 0.018 mg/l 8.56 mg/l in the waste samples, which showed beyond the limit (0.10 mg/l). it is not generally recognized as an essential growth element. pratt, (1972) reported that the conservative limits recommended due to lack of knowledge on its toxicity to plants. according to bandyopadhyay and biswas, (1998) the chromium is one of the toxic heavy metals and because of its wide application; there is urgent need to remove the chromium compounds from various polluting streams. sharma and forster, (1993) observed two forms of chromium; trivalent and hexavalent, which are found in industrial wastewater. the hexavalent form cr (iv) is more toxic to human than the trivalent form. baisakh and patnaik, (2002) observed in the animal experiments that acutely toxic doses of cr (iii) fall in range of g/kg of body weight. dietary intake of cr (iv) in mg/l levels produces chronic toxicity causing erosion of gastrointestinal tract and kidney lesions. the cadmium was recorded 0.001mg/l 8.56 mg/l in the waste samples. in the environments, cadmium is reported toxic to animals and microorganisms. according to national academy of sciences (1972), the cadmium is toxic to beans, beets and turnips at concentrations as low as 0.1 mg/l in nutrient solutions. conservative limits recommended due to its potential for accumulation in plants and soils to concentrations that may be harmful to humans. usepa, (2000) reported that cadmium accumulates especially in the kidneys leading to dysfunction of the kidney with increased secretion of proteins in urine. intake of cadmium is generally based on diet, particular vegetables and corn products. the lead was recorded 0.003mg/l 8.56 mg/l in the samples. the permissible limit of lead is 5 mg/l. according to pratt and nas, (1972) lead can inhibit plant cell growth at very high concentrations. usepa, (2000) reported that lead influences the nervous system, 281 afr. j. environ. econ. manage. ajit et al. 282 table 3.: limits of heavy metals in drinking water as bis specification and apha guidelines s. no. parameter/ unit standard limit characteristics desirable permissible limit limit 1. arsenic mg/l 0.05 nr* 2. aluminium mg/l 0.03 0.2 3. calcium mg/l 75 200 4. cadmium mg/l 0.01 nr 5. chromium mg/l 0.05 nr 6. copper mg/l 0.05 1.5 7. iron mg/l 0.3 1.0 8. magnesium mg/l 30 100 9. manganese mg/l 0.10 0.30 10. lead mg/l 0.05 nr 11. zinc mg/l 5 15 *nr: no relaxation table 4. maximum conc. level for heavy metal conc. in air, soil and water (unepa) heavy metal max conc. in air max conc. in sludge max conc. in drinking water max conc. in aquatic life (mg/m 3 ) soil (mg/kg) (mg/l) (mg/l) cd 0.1-0.2 85 0.005 0.008 pb __ 420 0.001 0.0058 zn 1.5 7500 5.00 0.0766 hg __ <1 0.002 0.05 ca .5 tolerable 50 tolerable>50 ag 0.01 __ 00 0.1 as __ __ 0.01 __ (adapted from usepa, 1992; washington code, 1992) slowing down the nerve response and also influences learning abilities and behavior. children are exposed to lead right form their birth, as children in the embryonic stage receive lead from the mothers through the blood (who, 2004). the cobalt was observed 0.002mg/l 0.905 mg/l in the samples. the threshold limit of cobalt is 0.05 mg/l. pratt, (1972) observed that cobalt is toxic to the plant especially tomato at 0.1 mg/l in nutrient solution, it tends to be inactivated by neutral and alkaline soils. according to glick (2003), heavy metal contamination can be a consequence of industrial activities that eliminate residues in the soil that in long terms, promote their accumulation. zenker et al., (2005) reported that the majority of the sources are originated by human actions like metal manufacture and mining industries with storage, disposal and transportation problems. analysis of a polluted environment with heavy metals from other sources such as cu and zn in animal manures (christie and beattie, 1989), run-off from timber treatment plants (bardgett et al., 1994), past applications of cucontaining fungicides (zelles et al., 1994) and analysis of soils in the vicinity of metal-contaminated army disposal sites (kuperman and carreiro, 1997) confirm that a decrease in the microbial biomass occurs at a relatively modest, and sometimes even at a low (dehlin et al., 1997) metal loading (ghorbani et al., 2002). metals when present in our body are capable of causing serious health problems, by interfering with, our normal body functions (ray and ray, 2009). some of these metals are useful to the body in low concentrations like arsenic, copper, iron and nickel but are toxic at high concentrations. other metals like aluminum, beryllium, cadmium, lead and mercury have no biological functions and are highly toxic disrupting bodily functions to a large extent. they disrupt bodily functions by accumulating in table 5: effluent discharge standards (bis) aluminium mg/l 5 arsenic mg/l 0.1 beryllium mg/l 0.1 boron mg/l 0.75 cadmium mg/l 0.01 cobalt mg/l 0.05 copper mg/l 0.5 iron mg/l 2.0 lead mg/l 0.05 lithium mg/l 2.5 manganese mg/l 0.2 mercury mg/l 0.005 molybdenum mg/l 0.01 nickel mg/l 0.1 selenium mg/l 0.02 sodium mg/l 200 total chromium mg/l 0.05 vanadium mg/l 0.1 zinc mg/l 2 table 6: threshold levels of trace elements for crop production (mg/l) s. no. element symbol limit remarks 1 arsenic as 0.10 toxicity to plants varies widely, ranging from 12 mg/l for sudan grass to less than 0.05 mg/l for rice. 2 cadmium cd 0.01 toxic to beans, beets and turnips at concentrations as low as 0.1 mg/l in nutrient solutions. conservative limits recommended due to its potential for accumulation in plants and soils to concentrations that may be harmful to humans. 3 cobalt co 0.05 toxic to tomato plants at 0.1 mg/l in nutrient solution. tends to be inactivated by neutral and alkaline soils. 4 chromium cr 0.10 not generally recognized as an essential growth element. conservative limits recommended due to lack of knowledge on its toxicity to plants. 5 copper cu 0.20 toxic to a number of plants at 0.1 to 1.0 mg/l in nutrient solutions. 6 fluoride f 1.0 inactivated by neutral and alkaline soils. 7 manganese mn 0.20 toxic to a number of crops at few-tenths to a few mg/l, but usually only in acid soils. 8 nickel ni 0.20 toxic to a number of plants at 0.5 mg/l to 1.0 mg/l; reduced toxicity at neutral or alkaline ph. 9 lead pb 5.0 can inhibit plant cell growth at very high concentrations. 10 zinc zn 2.0 toxic to many plants at widely varying concentrations; reduced toxicity at ph > 6.0 and in fine textured or organic soils. source: adapted from national academy of sciences (1972) and pratt (1972). vital organs and glands in the human body such as in the liver, bone, kidney, heart, brain. they also displace vital nutritional minerals from their proper place in the body to provide biological functions e.g. lead or cadmium displaces calcium in an enzyme reaction disrupting the enzyme reactions to a large extent. as their impact in the body, is at such basic levels that they are the casual factors in multiple health problems. leonard et al., (2004) reported that the metal causes genotoxicity as they affect the dna and immunotoxicity as they are major irritants to the body. the genomic instability by these metals induces cancer. heavy metals pollution such as copper, cadmium, lead, mercury, arsenic and chromium has been classified as a priority pollutant by the department of environment. continuous monitoring of heavy metals level in the environment is very important since it cannot be degraded and becoming public health problem when increased above acceptance level. health problem due to heavy metals pollution include nausea, vomiting, bone 283 afr. j. environ. econ. manage. ajit et al. 284 complications, nervous system impairments and even death become a major problem throughout many countries when metal ions concentration in the environment exceeded the admissible limits (mccluggage, 1991). due to that, various treatment technologies had been searched to reduce the concentration of heavy metals in the environment. sawyer and mccarty, (1979) reported that the heavy metal include lead (pb), cadmium (cd), zinc (zn), mercury (hg), arsenic (as), silver (ag) chromium (cr), copper (cu) iron (fe) and the platinum group elements. usepa, (2000) defined the pollutant that any substance in the environment, which causes objectionable effects, impairing the welfare of the environment, reducing the quality of life and may eventually cause death is known as pollutant. such a substance has to be present in the environment beyond a set or tolerance limit, which could be either a desirable or acceptable limit. living organisms require varying amounts of heavy metals. some metals viz. iron, cobalt, copper, manganese, molybdenum and zinc are required by humans. excessive levels can be damaging to the organism. other heavy metals such as mercury, plutonium and lead are toxic metals that have no known vital or beneficial effect on organisms and their accumulation over time in the bodies of animals can cause serious illness (leonard, 2004). nies (1999) observed that the metals may present in the earth’s crust only in very low amounts or the ion of the particular heavy metal may not be soluble. many investigators (garbarino et al., 1995; inecar, 2000; european union, 2002) observed that the metals are leached out and in sloppy areas and carried by acid water downstream or run-off to the sea. conclusion study reveals the heavy metals present above the permissible limit in the waste (solid and liquid). the minimum zinc content was recorded 0.45mg/l in solid waste of almora city and the maximum (11.9mg/l) in the liquid sample of roorkee city, which was beyond the limit.the waste having metal beyond maximum permissible level, should not dispose into the dustbins/gutters/municipality waste dumps. the heavy metals are toxic for crops; they reduce the crop yields and cause diseases in the plants. periodic analytical testing of heavy metal must be carried out for maximum permissible level to ensure that the pollutant removed is not introduced back. properly channeled drain with equalizing pipes to ensure regularized and monitored flow of liquid waste onto the dump sites will help keep the heavy metal free environment. there should be public education on the economic as well as the environmental importance of heavy metals and their toxic effects. there should be laws that will prevent the disposal of electronic waste. acknowledgement authors are thankful to prof. j.p. bhatt, hod biotechnology and zoology, hnbgu (a central university) srinagar garhwal (uttarakhand) india for his valuable suggestions and dr. gaurav gupta, director himachal institute of life sciences, paonta sahib (hp) india for providing the lab facility. the authors are also grateful to dr. a.k singh, scientist c, wadia institute of himalayan geology for technical support and k.p rathoure (mrs.) for valuable comments. references apha (1998). standard methods for the examination of water and wastewater, 18th ed. american public health association, washington, dc: 45-60. ashok k, bisht, bs joshi vd, indu b (2010b). estimation of heavy metals and metalloids from waste water of bindal river dehradun, jou.env. bios. 24 (2) 195-198. baisakh pc, patnaik sn (2002). removal of cr (iv) from aqueous solutions by adsorption, indian journal of environment and health 44:189. (in hindi with english abstract). bandyopadhyay a, biswas mn (1998). removal of hexavalent chromium by synergism modified adsorption.indianj.environ.pollut18, 662e671. bardgett rd, speir tw, ross dj, yeates gw, kettles ha (1994). impact of pasture contamination by copper, chromium, and arsenic timber preservative on soil microbial properties and nematodes. biology and fertility of soils 18, 71-79. christie p, beattie jam (1989). grassland soil microbial biomass and accumulation of potentially toxic metals from long-term slurry application. journal of applied ecology 26, 597-612. dehlin s, witter e, martensson am, turner a, bååth e (1997). where is the limit? changes in the microbiological properties of agricultural soils at low levels of metal contamination. soil biology and biochemistry 29, 1405-1415. dogbevi emmanuel k., e-waste is killing ghanaians slowly, august 27, 2007, http://ghananewsonline.blogspot.com/2007/08/e-waste-iskilling-ghanaians-slowly.html, retrieved on 3rd june 2008. epa (2000). wastewater technology sheet: chemical precipitation. united state environmental protection, epa 832-f-00-018. available on http://www.epa.gov/own/ mtb/chemical_precipitation.pdf. accessed 07/07/2010. european union (2002). heavy metals in wastes, european commission on environment. available on (http://ec.europa.eu/environment/waste/studies/pdf/ ferrari b, radetski cm, veber am, ferard jf (1999). ecotoxicological assessment of solid waste: a combined liquid and solid phase testing approach using a battery of bioassay and biomarkers. env toxic chem 18, 1195-1202. garbarino jr, hayes h, roth d, antweider r, brinton ti, taylor h (1995). contaminants in the mississippi river, u. s. geological survey circular 1133, virginia, u.s.a. (www.pubs.usgs.gov/circ/ circ1133/) gardea torresdey jl, peralta videa jr, rosa gd, parsons jg (2005). phytoremediation of heavy metals and study of the metal coordination by x-ray absorption spectroscopy. coord. chem. rev., 249(17-18): 1797-1810. ghorbani nr, salehrastin n, moeini a (2002). heavy metals affect the microbial populations and their activities. symposium 54, 2234-12234-11. glick br (2003). phytoremediation: synergistic use of plants and bacteria to clean up the environment. biotechnol adv; 21, 383-93. hussein h, farag s, kandil k, moawad h (2005). resistance and uptake of heavy metals by pseudomonas. process biochem. 40: 955-961. icmr (indian council of medical research), (1999); guideline for drinking water, new delhi. inecar (institute of environmental conservation and research) (2000); position paper against mining in rapu-rapu, published by inecar, ateneo de naga university, philippines knaebel db, federle tw, mcavoy dc, vestal jr (1994). effect of mineral and organic soil constituents on microbial mineralization of organic compounds in a natural soil, appl environ microbiol; 60: 4500-08. kupernam rg, carreiro mm (1997). soil heavy metal concentrations, microbial biomass and enzyme activities in a contaminated grassland ecosystem. soil biology and biochemistry 29, 179-190. nard s.s, marres g.k, shi xl (2004); metal-induced oxidative stress and signal transduction. free rad biol med 37:1921-1942. malik a (2004). metal bioremediation through growing cells. environ int., 30: 261–278 massoud tajrishy, ahmad abrishamchi (2005). integrated approach to water and wastewater management for tehran, iran, water conservation, reuse, and recycling: proceedings of the iranianamerican workshop, national academies press. mccluggage d (1991). heavy metal poisoning, ncs magazine, published by the bird hospital, co, u.s.a nies dh (1999). microbial heavy-metal resistance. appl. microbiol. biotechnol. 51:730–750. ozer a, pirincci hb (2006). the adsorption of cd (ii) ions on sulphuric acid-treated wheat bran. j. hazard. mater., 137 (2), 849-855. pinto violet n (2009). e-waste hazard-the impending challenge, http://medind.nic.in/iay/t08/i2/iayt08i2p65.pdf, retrieved on: 14th oct, 2009. pratt pf (1972). quality criteria for trace elements in irrigation watsrs. california agricultural exteriment station. 46 p. ray, suranja a, ray, manas kanti (2009). bioremediation of heavy metal toxicity with special refeece to chromium, al ameen j med sci., 2(2):57-63. savitha j, sahana n, praveen vk (2010). metal biosorption by helminthosporium solania simple microbiological technique to remove metal from e-waste, current science 98 (7); 903-904. sawyer cn, mccarty pl (1979). chemistry for environmental engineering 3 rd edi mcgraw hill inc., new york. snedecor gw , cochran w g. (1982). statistical methods. 7th ed. the iowa state university press. ames, ia. srivastava richa, kumar dinesh, gupta sk (2005). bioremediation of municipal sludge by vermitechnology and toxicity assessment by allium cepa, elsevier journal of bioremediation technology; doi: 10.1016/j.biortech.2005.01.029 statistical analysis systems. (2001), sas® user's guide: statistics, version 5 edition cary, nc. us epa (us environmental protection agency). (1982). an exposure and risk assessment for arsenic. epa 440/4-85-005. washington, dc, us environmental protection agency. who (1999); guidelines for drinking water quality, 2 nd ed.; geneva, pp. 97-100. who. (2001). arsenic and arsenic compounds. 2nd edition. environmental health criteria 224. united nations environment programme, the international labour organization, and the world health organization publishers. zelles l, bai qy, ma rx, racwitz r, winte k, beese f (1994). microbial biomass, metabolic activity a nutritional status determined from fatty acid pattern and poly-hydroxybutyate in agriculturallymanaged soil. soil biology and biochemistry 26, 439446. zenker mj, brubaker gr, shaw dj, knight sr (2005). passive bioventing pilot study at a former petroleum refinery. in: proceedings of the international symposiumin situ and on-site bioremediation 8th, baltimore, md, united states, june 6-9, 2005. 285 afr. j. environ. econ. manage. in ternationa l scholars journa ls african journal of environmental economics and management issn 2375-0707 vol. 7 (6), pp. 001-005, june, 2019. available online at www.internationalscholarsjournals.org © international scholars journals author(s) retain the copyright of this article. full length research paper nomograms for calculating the safety factor of homogeneous earth dams in long-term stability rida lakehal1*, lakhdar djemili1 and larbi houichi2 1 department of hydraulics, badji mokhtar university, annaba, 23000 annaba, algeria. 2 department of hydraulics, hadj lakhdar university, batna, 5000 batna, algeria. accepted 21 march, 2019 the slope stability analysis is routinely performed by engineers to evaluate the stability of embankment dams, road embankments, river training works, excavations and retaining walls. to ensure the geotechnical safety of the dam, the slope of embankment must be correctly designed and constructed. in this work, by applying the modified method of bishop, an attempt was made to construct sets of nomgrams for the calculation of the safety factor of homogeneous earth dams under long term stability, which allow the user to get the optimal safety factor of the dam, immediately, according the material classification and the parameters of design, height and slope. key words: nomograms, safety factor, homogeneous earth dams. introduction in the state of annaba, eastern algeria, the construction of homogeneous earth dams increased, especially in areas dominated by agriculture. by considering the questions of security, it is absolutely necessary to study their stability in the various cases of loading especially in long-term case. the most popular method for stability analysis of these structures is the limit equilibrium method (lem), this method is widely used by engineers and researchers and it is a traditional and well established method. although the (lem) does not consider the stress strain relation of soil, it can provide an estimate of the safety factor of a slope without the knowledge of the initial conditions, with the result that the (lem) is favored by many engineers. the lem is well known to be a statically indeterminate problem, and assumptions on the distributions of internal forces are required for the solution of the safety factor (cheng, 2006). a relatively large number of methods have been developed. among them, the slices method. in this method, the material above the slip surface being divided into a number of usually vertical slices. improvements in the methods have aimed on reducing the error due to oversimplifying the shape of the slip *corresponding author. e-mail: lakehal@hotmail.fr. tel: +213773-807526. surface and the resulting incorrect determination of the normal stress. the latter is potentially important for frictional materials where the shear strength will depend on the normal stress. the principal methods are described in the papers of fellenius (1936), bishop (1955), morgenstern (1965), janbu (1973), and sarma (1979). in this work, by applying the modified method of bishop, an attempt was made to construct sets of nomograms for calculating the safety factor (sf) which characterizes the stability of these homogeneous structures. as such, many calculations would be carried out starting from the structure of simplified cross of the dam. lastly, nomograms remain a contribution approach based on variations of the main properties in the long-term stability (lakehal, 2011). methodology data the data used ar e r elat ed to the geometrical properties of the works, mechanical properties of materials, and software employed (lakehal, 2008). geometrical properties of the works in figure 1, the simplified cross adapted for calculations, which represent the inclination (1/x, x in meter) for the upstream and mailto:lakehal@hotmail.fr figure 1. cross simplified adapted for calculations. downstream slope, are 1/3 and 1/2.5, respectively. a filter of two layers was seen for the upstream slope with a thickness of 0.2 m fine sand and 0.3 m coarse sand, while a drain with length fixed at 1/3 of the width of dam with a thickness of (1 m) constituted the three layers (0.3 m fine sand, 0.3 m coarse sand, 0.4 m gravel) (lakehal, 2008; alonso,1996; colomer, 2009). the geometrical characteristics of the embankment taken into account are: the width of the crest (b) corresponds roughly to the formula of knnapen, b=1.65 h (1) h: height of dam in meter, the unevenness {d = hp + r} (alonso,1996; lakehal, 2011). mechanical properties of materials the materials used in construction of these homogenous structures are intact or compacted fine materials, these materials have values of cohesion (c’) and friction angle (φ') seldom out of the following natural limits: (5 to 30 kpa for c’ and 15 to 40 for φ'), that is to say a fork of 25 kpa and 25°. we can obtain characteristics which are very poor (c' = 10 kpa and φ' = 20), excellent (c’ = 25 kpa and φ' = 35) or average (c' = 20 kpa and φ' = 25) (alonso, 1996; degoutte, 2002; duncan, 2005), the value of the density of these materials is chosen as the average value (usbr, 2001). in this case the density is taken as 20 kn/m 3 (alonso, 1996; colomer, 2009). software used the nomograms are results of several calculations by the geostab software (version 2004) based on limit equilibrium methods. the method of calculation is that of bishop modified (géostab, 2004; hammouri, 2008). methods in this work a series of nomograms for calculating the safety factor of the slope of an homogenous earth dam have been produced (colomer, 2009). the first set can be used for dams with height equal 10 m, 20 m and 30 m, with (1/2.5) value of inclination for downstream slope, the values of materials properties varied between: 10° to 35° for effective friction angle (φ’), and 10 kps ,20kps and 30 kps for effective cohesion (c’) (alonso, 1996; degoutte, 2002; lakehal, 2008). the second sets for height equal 10 to 30 m, with different inclinations for downstream slope were analyzed, their values being: 1/2 to1/4 (lakehal, 2008; colomer, 2009), with the type of materials very poor (c' = 10 kpa and φ' = 20) and average (c' = 20 kpa and φ' = 25) (degoutte, 2002; lakehal, 2008) . the nomograms developed in this study allow the user to know immediately the safety factor (sf) of dam with a known height, inclination and mechanical properties of materials.the value of safety factor sf =1.5 is set as a minimum value to ensure the stability of earth dam in long-term stability (alonso, 1996; degoutte, 2002). the stability of downstream slope should be analyzed (us army, 2003).the first nomograms are represented in figure 2 for downstream slope. figure 2 show results for embankments with a height of less than 30 m and inclination of (1/2.5), the nomograms have a decimal scale to interpolate values of sf in the case when the interpolation is required.the second nomograms are represented in figure 3 for downstream slope. figure 3 show the results for embankments with a height of less than 30 m with different values of inclination (1/2.5 to 1/4), in this case the user can determine the optimal safety factor from the height of the dam, type of materials and the inclination of slope. it can also determine the optimal inclination adopted for an optimal safety factor in the opposite sense. results and discussion practical implementation in figure 2, four different nomograms are shown, in which tow practical implementations have been applied: (i) the implementation of the nomograms on an earth dam with a height of 10 m, the inclination of downstream slope is (1/2.5) and the width of the crest is 5 m, the effective cohesion: c’ = 22 kps, effective friction angle: φ' = 15°, the result of sf is located between: 1.9 to 2.1 and by interpolation, the result of sf is 2.056. for the same dam, we can obtain the optimal safety factor sf =1,5 with the values of materials proprieties: c’ = 17 kps, φ' = 12°. (ii) the implementation of the nomograms an earth dam figure 2. set of nomograms for calculating the sf of earth dam between 10 to 30 m height. figure. 3. set of nomograms for calculating the sf of earth dam between 10 to 30 m height. with a height of 20 m, the inclination of downstream slope is (1/2.5) and the width of the crest is 7 m, the effective cohesion: c’ = 22 kps, effective friction angle: φ' = 15°, the result of sf is located between: 1.3 to 1,5, is lower than 1,5, to get a value of sf equal 1.5 or higher one needs to increase the inclination of downstream slope at (1/2.75). in figure 3, the implementation of the nomograms an earth dam with a height of 20 m, the inclination of downstream slope is (1/2.75) and the width of the crest is 7 m; with the type of materials is very poor (c' = 10 kpa, φ' = 20°), the result of sf is located between: 1.5 to 1.6 and, by interpolation, the result of sf is 1.575, the process is similar as in other nomograms. conclusion the nomograms shown in this paper are a suitable tool for quickly calculating the sf of homogenous earth dams (up to thirty meters high). they do not need complicated calculations or computer programs. it is only necessary to know its mechanical and geometrical properties (height and inclination of slope). every nomogram allows the inclination of the slope in a dam to be optimized. hence, for a given height of dam, and according to the type of material and optimal safety factor, the nomogram will give the optimum inclination of a slope that is stable. although, the nomograms remain a contribution approach based on variations of the main properties in the long-term stability. references alonso b (1996).the effect on the stability of earth dams consistent with the variation of key parameters. french mag. geotech., 63: 18-37. bishop aw (1955). the use of the slip circle in stability analysis of slopes. geotechnique, 1: 7-17. colomer m (2009). safety factor normograms for homogeneous earth dams less than ten meters high. j. eng. geol., 0013-7952, elsevier, pp. 65-73. cheng ym (2006). three dimensional slope failure analysis by the strength reduction and limit equilibrium methods. j. comput. geotech. elsevier, 36:65-73. degoutte g (2002). small dams. cemagref editions.179 p, isbn. 2 85362 551-6. duncan j (2005). soil strength and slope stability, library of congress cataloguing-in publication data. 450 p, issbn 0-471-69163-1. fellenius w (1936). calculation of the stability of earth dams, transaction. 2nd international congress on large dams. icld, washington, dc., pp. 445-459. janbu n (1973). slope stability computation. embaankment dam engennering-cassagrande volume. john wiley. hammouri n (2008). stability analysis of slope using the finite element method and limiting equilibrium approach. copyright springer-verlag. j. eng. geol. environ., pp. 80-88. géostab software (2004). manual de l’utilusateur.135 p. lakehal r (2008).study contribution to the influence of geometric, geotechnical and hydraulic stability of homogeneous earth dams. magister thesis badji mokhtar university. annaba. algerie, p. 100. lakehal r (2011). a study of long term effect of geotechnical factors on stability of homogenous earth dams. j. geogr. regional plann., 4(5): 279-286. morgenstern nr, price ve (1965). the analysis of the stability of general slip surfaces. geotechnique, 15(1): pp. 79-93. sarma sk (1979). stability analysis of embankments and slopes. j. geotech. eng. div. asce., 105.n°gt12. pp. 1511-1524. usbr (us. bureau of reclamation) (2001). us. bureau of reclamation. http://www.usbr.gov. us army (us army corps of engineering) (2003). engineering manual. engineering and design slope stability. us army corps of engineering, 205 p. african journal of environmental economics and management vol. 1 (5), pp. 167-176, december, 2013. available online at www.internationalscholarsjournals.org © international scholars journals full length research paper economic of biodiversity: the importance of studies aimed at assessing the economic value of biological diversity aynur demir aksaray university, turkey. accepted 15 september, 2013 biological diversity has constituted the focal point of environmental economics and public politics increasingly over recent years. ecological and economic approaches guide the determination of accurate policies for a sustainable future and in drawing an efficient roadmap. based on an extensive literature review, this study reveals both the importance and limitations of studies aimed at the economic value of biological diversity within the descriptive analysis and the method of group evaluation. in this study, it is shown directly that, studies which are based solely on biodiversity are seen to be insufficient. it is said that, the use values and non-use values of biodiversity to be determined as monetary and it is understood that, further policies can be developed on this subject. this study targeted an interpretation of the economic valuation concept by approaching key studies aimed at building bridges between a nation’s ecology and its economy. revealing the value of the biological diversity both quantitatively and qualitatively, these studies reflect the difficulty in not only assessing the accurate evaluation regarding species and genetic differences, but also the ecological and economic substitution of possible biological diversity losses. key words: biological diversity, economic valuation, species diversity, ecosystem diversity, bio-prospecting value introduction biodiversity had been included into the economic policies and the sustainable development model as a rising value in terms of economy and ecology during the 21st century. biodiversity plays an important role in the global economy and sustainable development due to two main reasons. “the first is that, it provides a wide range of direct or indirect benefits to mankind, which occur on both local and global scales. the second relates to how human activities have contributed to unprecedented rates of biodiversity loss, which threaten the stability and continuity of ecosystems as well as their provision of goods and services to mankind (nunes and van den bergh, 2001; nunes and nijkamp, 2011). complex biodiversity indicates a healthy environment and a process of life-support required for the welfare of people through the various goods and services. biodiversity, which is also an important part of economical development, is classified as scarce resources in the scope of economic goods, with a significant strategic power for both local and global economies (pearce and moran, 1994; tisdell and wilson, 2006). the common and sustainable utilization of this power may be possible with the transformation to an economical value providing all the components of biodiversity (species, genetic, and ecosystem diversity). therefore, attentions have shifted to the marketable demir 5377 demir 167 figure 1. methodological approach for valuation of biodiversity (adopted from de grood et al., 2002). goods and services directly provided from both local and global biodiversity together with the analysis and evaluation that highlights the negative economic value of biodiversity loss. the economic valuation studies which are based on an entirely human-centered approach take into account direct and indirect values of the production, consumption and unused values of biodiversity and they provide an opportunity to determine the monetary value on the basis of income to the mentioned values restricted (costanza et al., 1997; nunes et al., 2003; saunders et al., 2006; de groot et al., 2012). this economic valuation allows for a monetary evaluation of the value of biodiversity on the basis of revenue (freeman, 2003; l’opez, 2008). the determination of use and non-use values of biodiversity employs economical value techniques such as the market analysis, the production function, the hedonic pricing, travel cost and the conditional valuation (figure 1) (de groot et al., 2002; hoffman, 2011). research carried out on the determination of an economic value contribute to identifying the role of biodiversity on ecological and economic systems, providing a way to follow the negative impacts on species, ecosystems and related goods and service losses. within an ecosystem the extinction of a species has a direct affect on many other species and breaks down the previously existing balance (xepapadeas, 2010). as a result of this, it has been observed that, certain key functions within the ecosystem are not fulfilled both inside and outside the system, together with the arrival of new species. it is highly unlikely the incoming species will continue to fulfil the exact functions performed by the now extinct species, leading to a breakdown within the ecosystem and possible habitat loss (tisdell et al., 2006, 2007; nunes et al., 2006). in this way, gradually decreasing biodiversity that has material, moral and functional values will disrupt the balance of nature and at the same time causing economical losses and the further extinction of some sectors. furthermore, these economic valuation studies have a significant role in the conservation of biodiversity, through increased monitoring and the subsequent creation of necessary policies. historically, the bulk of research into biodiversity has been limited to species determination, identification and characterization, classification studies. only recently this research turned towards highlighting the potential economic value of biodiversity. in recent years, research focus has been directed towards the transformation to the economic value of biodiversity by biologists, environmentalists and economists. this research stresses that, to transform the natural world and its biodiversity with all its components to a purely economic value, it must be supported by a multidisciplinary 168 afr. j. environ. econ. manage. approach, while taken into consideration conservation and sustainable use. under these conditions, it is seen that, economic valuation studies have become increasingly important for developing countries which have a rich biodiversity. such approaches underline the relevance of policies all set to be transformed to the economical value of biological scarce resources. therefore, stricter implementation of both local and international economic policies must be maintained to ensure the sustainable use of biologically scarce resources and the conservation of a regions biodiversity for future generations. in this context, this research has analysed and displayed some key economic valuation studies emphasizing the importance of biodiversity with qualitative and quantitative sizes. it is clear that, the paucity of economic valuation studies plays a limited role in the determination of the direct and indirect using value of biodiversity, in the determination of the goods and services real value is offered by ecosystems and in the market analyses. it is important that, the expression of total economic value of biodiversity remains stable through the use of various economic valuation techniques and can thus, be employed in the development of applicable economic policies. this research is necessary in highlighting where there is a lack of relevant data and what manner of economic valuation studies have been done so far. it therefore targets which areas and in which sectors the valuation of biodiversity is significant. additionally, this research paper focuses on the analysis of biodiversity rather than merely natural resources, whilst looking into the use of experimental studies and the implementable evaluation methods and analysis the role played by recent biodiversity policy and the management of biodiversity indicators and the value information. in this sense, this research will help to resolve this relative dearth of valuations within biodiversity studies. it is noted that, certain measures be taken to allow for the understanding of the economic importance of biodiversity and overcoming of this limited situation. method this research is based on an extensive literature evaluation. some published data were collected through the internet from between 1992 to 2012. the compiled literature was evaluated systematically and analytically and classified according to several factors, namely goods and service functions of biodiversity, value categories, economic valuation methods, the author and year of study, species, etc. in the evaluation studies a systematic elimination between the similar and consecutive studies was performed. the data set obtained was interpreted using “group evaluation and descriptive analysis methods”. these value categories are used in the measurement of economic value of the provided benefit from biodiversity. (i) the studies that were evaluated according to ecosystem functions to the biodiversity; the studies were evaluated regarding ecosystem functions and services (ii) the studies relating to genetic diversity and bio-prospecting (iii) the sample research describing biodiversity and the species protection; research evaluated a single species in the fauna and flora diversity (iv) the sample studies that evaluated the protection of natural habitat and many species the identified value categories are shown in tables. these value categories are interpreted and discussed analytically and systematically in accordance with the results and conclusions subsequently reached. findings and discussion data related to the findings obtained from the group assessment and descriptive analyses, based on the literature review, are shown in tables under main titles. further results were obtained through discussion. measurement of economic value of the provided benefit from biodiversity studies and methodologies that were evaluated according to ecosystem functions within existing economic valuation studies, it is unclear whether the focus is towards ecosystems and natural sources, and if they refer to biodiversity subjects or not. this is primarily due to the fact that, biodiversity is often associated with complex ecosystem functions and processes and how these can be linked to human welfare. giving an economic valuation to biodiversity has proven to be a very difficult issue. modelling and economic analysis of biodiversity comprehends the information and indicators of relations between the dynamics of ecosystems and the human economic activities. therefore, there is a socio-economic relationship with the geographical differentiation of the economic valuation studies in biodiversity which further complicates implementation. as a result, “the source evaluation” and “the biodiversity evaluation” have been misused and this situation has led to paucity in research on the economic value of biodiversity. according to the data gleaned from the literature, biodiversity creates various value categories within the ecosystem, including the regulation and production of habitats and formation function (table 1). while the regulation and habitat value categories constitute indirect using values, the production and information function are direct use values. likewise, while such ecosystem functions as a gas regulation, climate regulation, water reserve, soil control, and biological control constitute indirect use values. value functions such as nutritional value, value for use as raw material, genetic and medical resource value and aesthetic value constitute the indirect using values. both direct and indirect using values of ecosystem functions are evaluated through various approaches, including abstention cost, production demir 5379 demir 169 table 1. relationship between value functions of biodiversity, value and valuation techniques (costanzabet al., 1997; white et al., 2004; nunes and schokkaert, 2003; de groot et al., 2002, 2010a,b, 2012). s/n ecosystem function economic analysis method values possible methods value $/ha/year that was used regulation function 1 gas regulation 7-265 ac indirect use rc/cv/gv/fi 2 climate regulation 88-223 ac indirect use rc/cv/gv/fi 3 disruption value 2-7240 ac/rc indirect use fi/hp/gv 4 water regulation 2-5445 pd /ac/ fi indirect use rc/hp/gv 5 water reserve 3-7600 pd/rc indirect use ac/fi/tc/hp/cv 6 soil conservation 29-243 ac/rc indirect use fi/hp/cv/gv 7 soil composition 1-10 ac indirect use rc/fi/cv/gv 8 nutritional cycle 87-21100 rc indirect use ac/fi/cv/gv 9 waste control 58-6696 rc/cv indirect use ac/fi/hp/gv 10 pollination 14-25 rc/fi indirect use dm/cv/gv 11 biological control 142-195 rc/fi indirect use ac/cv/gv habitat function 12 shelter function 3-1523 pd/cv indirect use, existence value rc/fi/hp/gv 13 breeding function 142-195 pd indirect use ac/rc/fi/hp/cv production function 14 nutritional value 6-2761 pd/ fi/cv direct consump./option value rc/gv 15 raw material value 6-1014 pd/ fi/cv direct consump/option value rc/gv 16 genetic resource value 6-112 pd/ fi direct consump/option value rc/cv/gv 17 medical value 203-3248 pd/ fi direct consump/option value ac/rc/cv/gv 18 decorative value 3-145 pd/ fi direct consumptive use rc/tc/cv/gv information function 19 aesthetic information 7-1760 hp direct non-consump use, rc/tc/cv/gv function existence value 20 recreation and 3-6000 pd/fi/tc/hp direct non-consump use, rc tourism value existence value 21 cultural and artistic +++ cv direct non-consump use dmp/fi/tc/hp/gv value 22 moral and historical 1-25 cv direct non-consump use, tc/hp/gv value existence value 23 value of use in +++ cv direct non-consump use fi/tc/cv/gv science/education dmp, direct market pricing; fi/pf, factor income/production function; ac, avoided cost; rc, replacement cost; hp, hedonic pricing, tc, travel cost; cv, contingent valuation; gv, group valuation. function, substitution function, travel cost, conditional valuation, and group assessment. as seen in table 1, the quality of the ecosystem, the goods and service function and whether ecosystem services have direct market value are important factors in determining the method to be used in valuation. one of the earliest studies to address biodiversity according to the value functions of the ecosystem is the study conducted by costanza et al. (1997). costanza et al. (1997) estimated the total value of 23 ecological functions to be $33 trillion/year for 17 ecosystems and 16 biomes through the use of various valuation techniques. it was estimated in the research conducted that, the value of the contribution of biodiversity to the nutritional cycle was $87 to 21,100/ha/year within the regulation function and it was foreseen the most important value element was medical resource value within the production function value category, which was 203 to $3,248/ha/year (table 1). this shows that, species and genetic diversity constitutes a significantly potential value in terms of biodiversity. in addition, the value of recreation and eco-tourism, which are important value 170 afr. j. environ. econ. manage. table 2. ecosystem functions and service valuation. author value category study value ($) crossman and bryan carbon regulation (2009) crossman et al. (2011) recreation and amenity value mullan and kontoleon multiple watershed (2008) services brander et al. (2007) reef recreation costello and ward (2006) bioprospecting value ricketts et al. (2004) pollination service kaiser and roumasset watershed conservation (2002) emerton (1999) water regulation/ watershed conservation laughland et al. (1996) water reserve value turner et al. (1995) life support value 15.8 million-ha study area agricultural areas of south australia. australia tropical forests for coffee production in costa rica mangroes and wetlands in malaysia and hawaii tropical forest in mount kenya milesburg pennsylvania well-watered ecosystems, swedish island $ 6–120/ha/year $ 1.5-10.2 /ha/year from $ 200/ ha/year to $ 1,000 /ha/year $ 184 per visit/year $ 14/ha -$ 65/ha $ 361/ha/year $ 845 ha /year-$ 1,022/ ha/year $ 273 ha /year from $ 14 households to $ 36 households from $ 0,4 million to $ 2 million pina (1994) ecotourism value mexico from $ 60/day to $ 100/ day elements of information function, was estimated to be $3 to 6,000/ha/year (table 1). the total of these values is defined as the maximization of social benefit obtained from biodiversity. the valuation studies in question allow for assessing and using biodiversity in an economically rational manner as well as better understanding the systematic relationships between the ecosystem functions. the diversity which in the goods and services mobility of ecosystem provides the life support systems needed for living beings and thus, occurs a critical interdependence. this essential interdependence is the phenomenon underlying the sustainable development approach. this situation plays a vital role in the sharing of benefit and to be maximized for social benefits that are provided from the goods and services mobility of ecosystem. mullan and kontoleon (2008) calculated the value of the benefit obtained from various watershed services to be $200 ha/year and $1,000 ha/year. costello and ward (2006) evaluated bio-chemicals, natural medicine and pharmaceutics ecosystem service flows in tropical forests. marginal value was estimated to range between 14/ha to $65/ha. ricketts et al. (2004), calculated the pollination value for coffee production in tropical forests as $361 ha/year (table 2). these figures indicate that, the transformation to the economic value of ecosystem services allows a clear link to the goods and service mobility of biological sources, and to the evaluation the ecological, the economic benefit and the benefit sharing processes. thus, the profit and loss analysis is done correctly in these subjects. in addition, this research gives an evaluation of ecological destruction which in turn may cause potential losses to ecosystem services. realization of this situation will create an awareness of the biological scarce resources which are providing positive added value and encouraging sustainable usage. evaluation of studies into genetic diversity and bioprospecting bio-prospecting is generally defined as research conducted into the genetic codes of living organisms demir 5381 demir 171 table 3. value of bioprospecting agreements (nunes and schokkaert, 2003; nunes and nijkamp, 2011). parties study value novartis and bioamazonia (2007) 10,000 samples of micro-organisms in brazil $ 4 million brazilian extracta and glaxo 30,000 samples from special area of brazil $ 3,2 million wellcome (1999) yellowstone national park and heat-resistant enzyme; taq polymerase and bacteria; $175, 000 diversa (1998) thermus aqyqticus inbio and merck (1991) 2,000 samples from genetic pool of costa rica $1 million (ding et al., 2007). genetic diversity which is the input of commercial products reflects the willingness of the drug industry to finance this research. marginal value of such an input where genetic information is transformed for medical purposes corresponds to the added value that it brings to the development of health services (ding et al., 2007; costello and ward, 2006). for instance, effective anti-cancer and anti-leukaemia drugs were discovered during research conducted on plants by the u.s. national cancer institute (craft and simpson 2001; nunes et al., 2003). bio-prospecting agreements concluded between governments and drug industries imply the importance of financial indicators for such biodiversity values (artuso, 2002). the most remarkable of these agreements was the incentive launched between merck and co. ltd., the biggest drug company of the world, and instituto national de biodiversidad (inbio) in costa rica. when the contract was signed in 1991, merck paid $1 000 000 and accepted to pay a royalty fee with the discovery of each new product. subsequently, inbio bristol-myers squibb signed contracts with other companies and nongovernmental organisations obtaining genetic resources (ten and laird, 1999; nunes et al., 2003; ding et al., 2007; costello and ward, 2006). a similar agreement was signed between diversa, a biotechnology company based in san dieago, and the u.s. based yellowstone national park. diversa accepted to pay $175,000 to yellowstone to conduct bio-technological studies within national park spas on heat-resistant micro-organisms (sonner, 1998; macilwain, 1998; nunes and nijkamp, 2011). likewise, brazilian extracta accepted to pay $3.2 000 000 to glaxo wellcome company annually for 30,000 samples consisting of bacteria, fungi, and plants (bonalume and dixon, 1999; nunes and nijkamp, 2011) (table 3). these agreements and the related studies indicate that, the economic value of genetic diversity is positive. in the last century, biological genetic resources have become extremely popular with research and development laboratories in biotechnology for life science and medical companies. companies, especially big multinational corporations are forced to sign up to bio prospecting agreements with many obvious benefits, such as the decrease of production process cost, the easy process of genetic material, the acceleration of production process, and buying power. particularly, modern bio-technology organisms are not evaluated as a whole, only being evaluated down to the level of gene. it is remarkable that the willingness of the individual to pay (wtp) rise of bio-technology and medical companies for each gene source and process. from this perspective, all living organisms have an economic value and will be turned into a commodity. in this respect, gene diversity has created the added value and benefit economically. however, the wtp values of these companies have ignored the potential effect of genetic diversity in the new medicine and product development, in the use of plant and animal materials. the ethical values and indirect values of genetic diversity are not included in the market value of contracts. it would therefore be more realistic to interpret as the minimum of economic value of genetic diversity changing. case studies on biodiversity and species conservation this study shows that, the economic value of species can be measured with all aspects. however, it is determined that, the study of species protection is perceived as a vital part of the forest ecosystems and wildlife ecosystems conservation and it is seen that, the economic valuation studies are limited solely to biodiversity. the limitation of these studies should be perceived as a big problem for the examination of biodiversity at the species level (single/multiple). this situation is made more difficult with the addition of value and indicator information, and understanding ecosystem processes and relationships with other species, the presentation of real economic value of biodiversity. this research has repeatedly stressed that, previous studies about this subject have been largely insufficient in their scope and conclusions. as research into the economic valuation of biodiversity goes into private biodiversity areas directly and looks at all factors and components 172 afr. j. environ. econ. manage. table 4. single species valuation in fauna diversity. author study average wtp calculations (household/year) stanley (2005) bandara and tisdell (2005, 2003) and bandara (2004) tisdell et al. (2005a, b) tisdell and wilson (2004) hsee and rottenstreich (2004), kontoleon and swanson (2003) horne and pet¨ajist¨o (2003) cicia et al. (2003) bosetti and pearce (2003) giraud et al. (2002) macmillan et al. (2002) white et al. (2001) bowker and stoll (1998) stevens et al. (1997) jakobsson and dragun (1996) bostedt and bomen (1996) loomis and larson (1994) loomis and helfand (1993) van kooten (1993) streptocephalus woottoni $24,85 elephas maximus $ 1,94 petaurus gracilis $29.88 dendrolagus bennettianus $53.10 ailuropoda melanoleuca $ 13.81 alces alces $145,49 equus caballus $33,89 halichoerus grypus $12,83 eumetopias jubatus $73,83 anser sp $11,91 sciurus vulgaris $2,87 whooping crane conservation from $ 21 to $141 atlantic salmon restoration in a river, from $14,38 to $21,40 massachusetts leadbeater’s possum, australia $ 29 wolf conservation in sweden from 700 sek to 900 sek gray whale conservation, us from $16 to $18 conservation of different single $ 13 for sea turtles to $ 25 species, us for bald eagle conservation of water bird’s habitat sometimes from $ 50 to $ in wetland, canada 60 (per ha) influencing this subject, this insufficiency problem will be overcome. as the economic valuation studies on plant and animal species are collated, it is seen that, the economic value studies are more focused on single animal species (table 4), whereas single plant species studies have been more limited (table 5). the studies listed with only one animal species evaluated are seen on table 4. the calculations were derived from the contingent valuation (cv) practices and wtp) was determined to avoid the loss of some special species (venkatachalam, 2004; stanley, 2005). for instance, while van kooten (1993) calculated the wtp of a water bird living in a wetland in canada to range between 50 and $60 per ha, stevens et al. (1997) determined the restoration value of the atlantic salmon living in a river in massachusetts to range between 14.38 and $21.40. in the same way, stanley (2005), calculated that for streptocephalus woottoni wtp value is $24.85/year, tisdell et al. (2005a, b), for petaurus gracilis wtp value is $29.88/year and tisdell and wilson (2004), for dendrolagus bennettianus wtp value is $53.10/year. it can be understood and seen from the given examples that, the protection value of single species as economical is very high in the fauna diversity. table 5 lists the economic valuation studies conducted on a single plant species. it is seen that, the economic valuation studies on single or multiple species of flora are limited both qualitatively and quantitatively in the flora diversity which form the first key stage of the ecological cycle. besides, it is evaluated with goods and services as a source of timber within the forest ecosystems. this is derived from the complex structure of gene sources. in studies where various analysis methods were employed, functional valuation of single species plant diversity was carried out. for instance, lee (2002) analysed the value of orchid production in production farms in taiwan through the method of production function and calculated a value of $112,615/year for each farmer. in turkey, demir (2009) calculated the total value for ecosystem functions of galanthus elwesii as $68/per unit/year. the methods of market value, production function and conservation prevention cost were used in the analysis. demir (2012) also calculated the medical resource value of summer snowflake in turkey through the methods of production function and market analysis and estimated medical resource value as $4.5/per unit/year for each summer snowflake. when the social benefit to gain from the end product to be obtained with demir 5383 demir 173 table 5. valuation of single species in flora diversity. author study value demir (2012) demir (2009) erdem (2006) lee (2002) medical value in summer snowflake, turkey total economic value of goods and services related to galanthus elwesii, turkey conservation value of orchid, turkey economic analysis of orchid production of taiwan production plants, taiwan $ 4,5/per unit/year $ 68 /per unit/year $ 7 /household/year $377,231 / per farm/year and $112,615 /per farmer/year table 6. studies on conservation of natural habitat and valuation of multiple species. author study average wtp calculations (per household/year) aruoba (2007) başak (2003) turpie (2003) nunes (2002) roosen et al. (2001), région wallonne (2001) wiestra (1996) jakobsson and dragun (1996b) richer (1995) brouwer (1995) carson et al. (1994) hoevenagel (1994) value of ecological services of yumurtalık wetland, turkey tuz lake specially protected area, central anatolia, turkey conservation of south african biodiversity, fynbos biome in the western cape, for national biodiversity conservation of natural parks and wilderness areas conservation value for rouge de belgique cattle breeds and 5 different sheep breeds, belgium conservation of ecological agricultural fields, the netherlands conservation of all endangered species in victoria desert conservation in california conservation of marshy pasture areas kakadu conservation region and natural park conservation, australia improving wild life habitat in marshy pasture areas in germany, the netherlands $ 738 /ha/year $ 678,33/ha/year (total value) $ 8,4 million /year, $ 3,3 million/year,$ 58 million/year from $ 40 to $ 51 € 120 /subsidy/animal/year and € 20 /subsidy/animal/year nlg 35 (single-limited) $118 $101 from nlg 28 to nlg 72 $ 52 (little influence scenario) $ 80 (big influence scenario) from nlg 16 to nlg 46 desvousges et al. (1993) whitehead (1993) duffield and patterson (1992) halstead et al. (1992) conservation of immigrant water birds in central flyway from $ 59 to $ 71 nongame wild life conservation program $ 15 fishery conservation in montana rivers from $ 2 to $ 4 (for the residents), from $ 12 to $17 (for nonresidents) conservation of bald eagle, jackal and wild turkey in $ 15 england the processing of these plants is included in these values, the resulting added value will be even higher. the increase in the quality and quantity of studies of this area will be a guide to a more holistic understanding of the roles of plant species within an ecosystem. case studies on conservation of natural habitat and on evaluation multiple species some studies prefer associating the value of biodiversity to the value of conservation of natural habitat. case studies conducted in this respect are given in table 6. for instance, nunes (2002) conducted the first national cv application in portugal, carried out a wtp evaluation for the conservation of natural parks and wilderness areas and obtained an average wtp ranging between 40 and $51. besides, a cv study was conducted by bateman et al. (1992) to evaluate the financial value of conserving the norfolk broads. the results showed that, the residents of the norfolk broads had a wtp value of 174 afr. j. environ. econ. manage. £12 while those living in different regions of uk had a wtp value of £4 (table 6). hoevenagl (1994) carried out a wtp research by telling 127 farmers in the pasture areas in germany that they would receive grants from the government on condition that they used their fields in a manner benefitting the habitat of wild animals. the assessment revealed an average wtp ranging between nlg 16 and nlg 45. kealy and turner (1993) calculated the wtp value of the benefit obtained from conserving adirondack aquatic system to range between 12 and $18. siberman et al. (1992) examined the current value of coast ecosystems for users and non-users of new jersey coasts. the average wtp was found as $15.1 for users while it was found as $9.26 for non-users. lastly, halstead et al. (1992) calculated the wtp value for conserving bald eagle, jackal and wild turkey in new england as $15. when comparing multi-species and single species research, multi-species wtp values are significantly higher. the problem in the value account interpretation of species or habitat conservation is the missing connection between a special species or habitat and habitats in need of conservation. this is the primary difficulty in the economic value analysis of species and habitats. conclusion in this study biodiversity was analyzed at different levels: the ecosystem and its functions, genetic diversity and bioprospecting, species and habitats showing that, biodiversity should be evaluated using an interdisciplinary approach. in this way, biodiversity has been formulated with the other different components and has been transformed to an economic value using the various valuation methodologies. in addition, the economic value of biodiversity is affected and changed according to the level of diversity in habitat, the type of value, the applied valuation method, the geographic location and socio-economic structure. the main question which needed answering through this research was ‘how can we use the present research to formulate an integrated and effective framework to determinate the value of biodiversity?’ the answer to this question requires that, a clear life diversity level be chosen, a concrete biodiversity changing scenario to be formulated, the biodiversity within certain boundaries, and at last, having a particular perspective on the value of biodiversity. it was shown that, most economical studies, using the monetary valuation have actually confused biodiversity with biological resources. this situation has lead to a dearth of studies focused principally on biodiversity. additionally, it seems clear that in our assessment of economic valuation studies, the evaluation of biodiversity values does not give a stable or clear monetary value for biodiversity. therefore, it should be accepted that, the economic valuation studies have an inadequate perspective for the unknown value of biodiversity changes and obtained economic values and indicators are considered as a lower limit. to reiterate, the economic valuation estimates should be regarded as providing a very incomplete perspective on, and at the best lower bounds to the unknown value of biodiversity changes. however, it should be given a place to “the integrated ecological and economic models”. the integrated models can bring out several biological and economic (possibly monetary) indicators which are collected via the multi-criteria analysis techniques. it is possible to provide for a closer, innovative connection between modelling and valuation, among other methods, by generating conditional values for specific environmental-economic scenarios; using scenariomodelling outcomes such as tables and graphs in valuation experiments (e.g., contingent valuation) and using spatial models to aggregate monetary values related to specific areas. to date, most studies lack a uniform and clear perspective on biodiversity as a distinct, univocal concept. this situation is explained by many reasons. first reason is that, insufficient information exists on the quantity of species and the genetic variations within species. secondly, it is not known exactly the population analysis and the genetic variation value of species in a population. thirdly, the numerous functions among ecosystems and the value of interrelation diversity that occurs in the different ecosystems have not been fully taken into account. finally, the significant differing degree in the similar assets on the global level, the biodiversity values because of the unequal international income distribution. in order to determine unequivocally the total economic value of biodiversity, we should remove these obstacles. in conclusion, the available economic valuation estimates should be considered, at best, as a lower bound to an unknown value of biodiversity, and are always contingent upon the available scientific information as well as their global socio-economic context. as we have seen, biodiversity can be dealt with at different levels: genetic, species, ecosystem, and functional diversity. for the analysis and valuation of biodiversity at the ecosystem and functional levels, which may be regarded as the cornerstone of the analysis and valuation of biodiversity, an active interdisciplinary dialogue is necessary, with emphasis on the complex interface between natural science and social science disciplines. a comprehensive assessment of ecosystem biodiversity characteristics, structure, and functioning requires the analyst to take various important steps. firstly, the socio-economic causes and consequences of biodiversity degradation or loss should be determined. secondly, the negative impacts on biodiversity caused by human activities should be assessed. the range and degree of biodiversity functioning should be estimated, demir 175 especially in terms of ecosystem-functional relationships. finally, alternative biodiversity management strategies should be ranked and a joint spatial and temporal systems analysis of each policy scenario should be undertaken. however, the physical assessment of the functions performed by biodiversity is an essential prerequisite to any ecological evaluation. thus, simply identifying functions will be insufficient if we want to present resource managers and policymakers with relevant policy response options. valuation criteria for the function evaluations of species such as computer modelling, geographical information systems (gis), red data species lists and the biological value indexes must be further developed. this in turn will lead to evaluations in terms of the value of biodiversity, providing input to the production process, the effects on the regulation of human welfare and ecological functions. this approach to ecological evaluation 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vegetation types have been investigated in the desiccated uyun layla lakes from october, 2007 till may, 2010, except during the summer months. the vegetation in and between the 23 dolines was very poor. twenty xerophytic species were recorded mainly zygophyllum coccineum, zygophyllum simplex, salsola spp., traganum nudatum, haloxylon salicornicum, zilla spinosa, rhanterium epapposum and gymnocarpos decandrum. the importance value (i.v.) of all the species has been calculated and their taxonomic position has been described. the soil was sandy, yellowish white and very poor in minerals. in spite of that, the total soluble salts, calcium and copper contents were considerably high. the results have been discussed and interpreted according to the environmental changes occured in this area. key words: al-aflag, uyun layla, soil characters, vegetation. introduction wetlands in saudi arabia have been subjected to high pressure from both human activities and global warming. the report of the iucn (1984) indicated the destruction of the wetlands and change in the habitats in saudi arabia. mackey (2007, cited in taylor and figiis) predicts an interaction between climate change and other drivers of biodiversity that will increase extinction risk from what occurred in periods of rapid climate change in the past. sambas and symens (1993) pointed to the great loss of the wetlands in the gulf area. frazier and stevenson (1999) described the middle east area as being largely semi-arid to arid and they pointed to the lack of information in these areas. this is the state of saudi arabia, but there are some coastal or lowland areas receiving great amount of rainfall leaving ponds or sometimes lakes behind. uyun laila was an example of these lakes which originated from severe rainfalls during the winter season. these lakes, located 10 km south layla town in al-riyadh province, are a series of small to medium sized limestone karst lakes, which were unique in the arabian peninsula (newton, 1995). the lakes were popular recreational area in the past, given its proximity to riyadh and al kharj. these lakes have been subjected to direct human pumping for cultivation, resulting in the current dryness situation. due to the change in water availability, the vegetation and the soil characters have been altered. al-ghanem (2011) described the vegetation in these lakes by being scarce, restricted to few halophytic species. accordingly, more works are needed to investigate the ecological change in this area. for this reason, the present study is one of the projects used to evaluate the amount of salts and minerals in the soils of the dry dolines and the effect it has on the vegetation. study area the site area is about 3,000 ha. it is with an altitude of 540 m and 330 km. it is located south of al-riyadh city, the capital of saudi arabia. it comprises a total of 23 doline and sinkhole subsidence craters, of which five are shaped irregularly, the largest at about 1,500 by 500 m, and the other four ranging in size down to 250 by 75 m. the remainders are circular in shape, of which four measure between 100 and 175 m in diameter, and four are less than 100 m in diameter. nearly all the craters are completely dry. over-abstraction has caused extreme desiccation of the shallower dolines and sediments forming the crater walls and surrounding terrain. materials and methods monthly visits were done to the studied area from october, 2007 to may, 2010, excluded the summer times, to record the different plant species grown in this area. no quadrates have been done, but the 1 2 3 4 5 6 photographs 1 to 6. the different dry dolines. plant species grown in each doline have been recorded throughout the time of study. the importance value (i.v.) for each species was calculated as follows: i.v.= relative frequency+ relative density+ relative cover. soil samples from the 10 selected dolines have been taken from 25 cm depth of the dolines for chemical analyses. soil chemical analyses were done using x-ray method. photographs of selected doline have been taken. the different species have been identified and put in its systematic position in the faculty herbarium for further investigation. results and discussion succulent perennial species mainly xerophytes are dominating in and around the desiccated lakes. twenty perennial species were recorded during the studied period. these species are zygophyllum coccineum, zygophyllum simplex, aeluropus lagopoides, cressa cretica, limonium axillare, pennisetum divisum, lasiurus scindicus, ochradenus baccatus and fagonia bruguieri scattered in these dolines. while salsola spp., traganum nudatum, haloxylon salicornicum and haloxylon persicum are widely distributed at the flat bottom of the lakes. meanwhile artemisia spp., zilla spinosa, rhanterium epapposum, astragalus spinosus, gymnocarpos decandrum, achillea fragrantissima, halothamnus bottae, tephrosia apollinea are found as scattered individuals at the sloping edges of the desiccated lakes (photographs 1 to 15). not all of these species were found during all the studied period, but they were recorded during the whole period. the abundant species were z. coccineum, z. simplex, salsola spp., t. nudatum, h. salicornicum, z. spinosa, r. epapposum and g. decandrum. the taxonomic position according to cronquist (1981) and the importance values (i.v.) of these species are listed in table 1. generally speaking the vegetation was poor during all the studied period, it was scarce and restricted to few xerophytic species. the soil at the bottom of the dolines was loose, sandy and yellowish white, while the wall was calcareous and grayish white (photographs 1 to 15). analysis of the chemical contents of the soil listed in table 2 and illustrated in figures 1 4 shows that the soil is alkaline with high amount of total salt and calcium ions (figures 1 and 2). the amount of the investigated cations and anions is very low in all the analyzed dolines (figure 2 and 3). the soil was poor in phosphorous as its maximum amount was 2.9. meanwhile the copper content was considerably high reaching up to 15.4 (table 2 and figures 1 and 3). this data coincide with that obtained by jackson (1958), daubenmire (1959), al-sheikh and yousef (1981) and al-ghanem (2002). they found that the soil in the deserts is poor, alkaline with high soluble salt contents due to the rarity in rainfall. while the amount of cl and s is in reverse proportion where the increase in cl and decrease in s is expected in the deserts as found by almoneyeri et al. (1986). the phosphorous content was very low due to the poor vegetation in this area as shown by al-homaid et al. (1990 b). the high contents of copper have its poisonous effect on plant growth (al-haish, 1985). this increase in copper contents may be due to the pollution from urbanization and human activities in the area. 7 8 9 10 11 12 13 14 15 photographs 7 to 15. the poor vegetation and the sandy calcareous soil. table 1. species recorded and their taxonomic position and i.v. species i.v. order family phylla zilla spinosa 38.9 capparales brassicaseae ochradenus baccatus 11.7 resedaceae zygophyllum coccineum 107.3 zygophyllum simplex 112.5 geraniales zygophyllaceae fagonia bruguieri 6.89 halothamnus bottae 7.4 haloxylon salicornicum 89.5 haloxylon persicum 11.7 caryophyllales amaranthaceae s.l. salsola spp. 109.4 magnolophyta traganum nudatum 84.2 gymnocarpos decandrum 20.4 caryophyllaceae astragalus spinosus 5.8 fabales fabaceae s.l. tephrosia apollinea 3.8 limonium axillare 5.7 plumbaginales plumbaginaceae cressa cretica 1.8 solanales convolvulaceae rhanterium epapposum 22.6 campanulales asteraceae achillea fragrantissima 8.2 aeluropus lagopoides 5.8 lasiurus scindicus 7.2 poales poaceae liliophyta pennisetum divisum 10.4 table 2. mineral contents of the soil from 25 cm depth of 10 dolines. dolines 1 2 3 4 5 6 7 8 9 10 used materials min. mg 4.9 7.0 8.8 7.8 4.4 3.3 8.5 5.9 3.4 5.2 mgo si 6.2 6.9 8.4 8.9 6.2 6.1 8.4 6.4 5.8 6.2 quartz p 2. 8 2.1 1.7 2.1 2.2 1.9 2.9 2.0 2.1 2.2 gap s 4.0 2.6 3.2 2.9 2.4 2.6 3.8 3.8 4.1 2.8 fes2 cl 9.4 10.4 9.5 9.2 8.1 7.5 10.2 9.2 10.4 10.1 kcl k+ 10.4 9.2 10.1 9.8 8.6 8.2 10.3 6.7 10.2 8.8 mad ca ++ 35.6 36.6 41,6 44.2 52.0 60.2 54.3 52.1 41.6 39.2 wollas cu 15.4 13.4 6.4 7.9 7.2 6.1 5.2 7.1 10.8 15.3 cu zn 11.3 11.8 10.3 7.2 8.9 4.1 7.3 6.8 11.6 10.2 zn sum 100 100 100 100 100 100 100 100 100 100 figure 1. show the element contents mg, si and p in 10 dolines. figure 2. show the element contents s, cl and k + in 10 dolines. figure 3. show the element contents of ca ++ , cu and zn + in 10 dolines. 800 600 esc(mlmos/ cm) 400 200 0 1 3 5 7 9 figure 4. the total soluble contents. the vegetation in and between these desiccated dolines is greatly affected by the soil characters and environmental changes that were happening in this area. according to kent and coker (1992) the main purpose of studying the vegetation is to know the dynamic and to develop strategies to protect the threaten species. in the studied area, we recorded twenty perennial xerophytic species only, with low i.v. this can be due to soil characters, dryness and climatic stress as found by shaltout et al. (1997). meanwhile the absence of annual species can be due to the sandy soil which cannot hold sufficient rain water in the surface area, in spite of the elevation of the sea level in najd plateau, where uyun layla located. from this study we can conclude that, pumping of water from uyun layla has led to a severe damage to the ecological conditions in this area. this change caused desertification, and alteration in soil characters and vegetation type. it is therefore an urgent task to develop plans to sustain the wild life in this area and improve the habitats in this area. references al-ayesh fm (1985). the effect of copper and cadmium pollution on the growth and productivity of zea mays. m.sc. thesis, king abdul aziz univ. fac. sci. biol. dept., jeddah, k.s.a. al-ghanem wm (2002). comparative ecological studies on the natural vegetation of three different transects within al-riyadh region. ph.d. thesis, girls college of education, al-riyadh, k.s.a. al-ghanem wm (2011). ecological 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saudi arabia. in a directory of wetlands in the middle east, ed da scott, iucn, gland, switzerland and iwrb, slimbridge, united kingdom. sambas a, symens p (1993). developing a conservation plan for wetlands in saudi arabia: the ncwcd system plan for protected areas. in wetland and waterfowl conservation in south and west asia, proceedings of an international symposium, karachi, pakistan 14–20 december 1991, eds moser m, van vessem j, iwrb special publication no. 25, awb publication no. 85, iwrb, slimbridge, united kingdom, and awb, kuala lumpur, malaysia, pp. 109–112. shaltout kh, al-halawany ef, al-garawany mm (1997). coastal lowland vegetation of eastern saudi arabia. biodiv. conserv., 6: 1027-1040. in ternationa l scholars journa ls african journal of environmental economics and management issn 2375-0707 vol. 7 (1), pp. 001-010, january, 2019. available online at www.internationalscholarsjournals.org © international scholars journals author(s) retain the copyright of this article. full length research paper the cost of environmental lead (pb) poisoning in nigeria oladele a. ogunseitan* and timothy r. smith program in public health, college of health sciences, university of california, irvine, ca 92697-7070 usa. accepted 17 october, 2018 the pervasiveness of human health impacts and ecosystem effects of lead (pb) is not controversial, but there are serious arguments about the pace at which pb should be eliminated from consumer products. presumably, these arguments can be resolved by converting costs and benefits of pb use to similar units, a notorious methodological challenge for health impacts in developing countries. to estimate the costs of pb poisoning attributable to petrochemicals in nigeria, we conducted a meta-analysis of measured blood lead levels (bll) and we used published relative risk values for disease categories to estimate the proportion of overall disease burden attributable to pb. we modeled the health costs of pb exposure and we compared this to the cost of banning pb. we estimate that pb exposure accounts for 7 25% of the disease burden among nigerian children, costing the health and education sectors $0.38 – 1.15 billion year -1 for every 1 mg/dl increase in bll. in comparison, we estimate that a pb abatement program in nigeria will cost $0.076 – 0.23 billion year -1 . if a pb phase-out program is instituted now to lower the national bll to 1 mg/dl by 2020, a savings of $2.7-8.0 billion would be realized. key words: lead (pb) poisoning, cost-benefit analysis, diseases, petrochemicals africa. introduction exposure to pb is widely recognized as a major risk factor for several human diseases, and the structure of industrial ecological systems have made exposure to pb unavoidable for most people alive today (needleman, 1999; pruss-ustun et al., 2004; who, 2000). in affluent countries, sizable investments in the implementation of environmental policies prohibiting the addition of pb to many consumer products have resulted in rapid decline of human exposures, demonstrable by observed reductions in the human blood content of pb (usepa, 1985; grosse et al., 2002). unfortunately, the public health gains from extensive research on the adverse effects of pb and the remarkable successes of effective policies in these industrialized countries have not yet enveloped developing countries, and the course of gasoline-fueled industrialization remains hazardous to public health (oecd, 1999). *corresponding author. e-mail: oladele.ogunseitan@uci.edu. phone: 949-824-6350 fax: 949-824-2056. children throughout africa are particularly vulnerable to pb exposure because of unabated use of leaded gasoline and leadacid batteries in automobiles (nriagu et al., 1996 and 1997; omokhodion, 1994), and recently, unregulated cottage industries associated electronic waste recycling (lincoln et al., 2007). particular socio ecological and climatic factors also contribute to high levels of inhalation and ingestion of pb-laden aerosol and dust (laidlaw et al., 2005; ogunfowokan et al., 2004; ogun-sola et al., 1994; rankin et al., 2005) . despite the initiation of phase-out programs in a few countries, the gasoline sold in most african countries contains 0.5 0.8 g/l lead, the highest levels in the world (thomas, 1995). in nigeria, gasoline with average pb content of 0.66 g l -1 remains in use (fakayode and olu-owolabi, 2003) . in nigeria’s largest city of lagos, specific emissions of lead exceed 164 kg km -2 representing approximately 20% of the 2.46 gg of lead emissions nationwide (obioh et al., 1988), and ambient air concentration of pb ranges up to 9.58 g m 3 , exceeding who recommended annual average of 0.5 g m 3 at all locations (obioh et al., 2005). furthermore, mean blood lead levels (bpb) measured at various times and urban locations in nigeria have ranged from 11.4 – 25 g dl -1 ; far exceeding the 10 g dl -1 action dose recommended for the u.s. population (adebamowo et al., 2006; ademuyiwa et al., 2005; nriagu et al., 1997). in addition to automotive and industrial sources, elevated blood lead levels in children have been attributed to paint, household dust, overcrowding and low parental income (charney, 1982; kapu et al., 1989; kristensen et al., 1993; landrigan et al., 1976; nriagu and pacnya, 1988). previous studies in africa have also shown that one of the strongest indicators of childhood bpb was the family either owning a car or living in a house located on a tarred road (nriagu et al., 1996). these factors are typically only encountered in urban centers. however, the geochemical behavior of pb and its association with suspended particulates suggests that children in remote suburban or rural regions may also suffer from pb exposure, in which case, the adverse affects of pb should be widespread. this hypothesis has not been rigorously tested within the african continent. also, it has been relatively simple to quantify the financial costs associated with pb-phase out programs, but the economic costs of health effects attributable to lead exposure are typically externalized. this has made it difficult for policymakers to comprehend cost-benefit scenarios used to justify lead abatement programs. the goal of this research is to provide cost-benefit information to environmental policy makers in nigeria by employing a quantitative comparison of the health cost of lead-related disease burden to the cost of a national lead abatement program. there are three research objectives: (1) the determination of the representative blood-lead content of nigerian children (ages 1 6 yrs.) and subsequent contribution of environmental lead exposure to the burden of disease in nigeria; (2) the estimation of the health costs of environmental lead exposure in nigeria; (3) and the estimation of the cost of a national leadabatement program. methods assessment of lead exposure children (ages 1 – 6 years; n = 306) were recruited for this study through the scheduled immunization clinic in the semi-rural region of otukpo, nigeria (total population of approximately 136,800 people, of which 45% are younger than 14 years for the study period (population reference bureau, 2006). blood lead concentrations were determined by means of an automatic blood lead analyzer with a sensitivity range of 1.4 65 µg dl -1 based on blood sample volume of 50 µl (leadcare, esa inc., chelmsford, ma and andcare inc., durham, nc. the equipment was kindly provided by the u.s. centers for disease control and prevention, atlanta, georgia). the necessary size of the population sample was estimated within the desired margin of error for predicting the population mean according to moore and mccabe (2005): n  z  s 2  2.96  3.8 2  300 m.65 where: z = z-score (2.96, 99% ci) ; s = standard deviation (3.8 µg dl -1 ; nriagu et al., 1996); m = desired margin of error (± 0.65 µg dl -1 ) informed consent was obtained for all human subjects according to standard research ethics, and as approved by the institutional review board. exclusion categories included those previously treated for pb poisoning, those who had not been living in the same residence for at least the past 6 months, those who are being treated for severe illness, and those not accompanied by a legal guardian. in addition to the determination of bpb concentrations, a questionnaire was completed by each child subject with the legal guardian to record demographic and socioeconomic statistics and to assess predictors of pb exposure and the predominant pathways for such exposures. the questionnaire survey was modified from the standard instrument used by u.s. center for disease control and prevention to better capture the social, economic, and cultural environment of nigeria. with written consent, the nurse/phlebotomist administered the survey and offered the subject a fact sheet containing health information on lead exposure in children. association of lead exposure and disease burden lead exposure is implicated in several disease burden categories including systemic effects such as hypertension, gastrointestinal effects, anemia, nephropathy, and nervous system effects such as intelligence quotient (iq) defects and encephalopathy (atsdr, 1999; schwartz, 1991, 1993, 1994; schwartz et al., 1986). we estimated the contribution of pb exposure to the following disease categories in nigeria: genito-urinary disease, prematurity, dental caries, nervous system cancers, congenital anomalies, hypertension, cerebrovascular disease, low birth weight, and mild mental retardation (mmr; iq levels 50-69) . nine of the 106 disease categories included in the world health organization’s global burden of disease study were included in this study (murray and lopez, 1996; but see cooper et al., 1998). a population-adjusted, disease burden for nigeria was estimated from the regional burdens for relative risk analysis. the numerical model dismod ® was used to estimate disease burden for two disease categories that were not included in the gbd, prematurity and mild mental retardation (http://www.hsph.harvard.edu/organizations/bdu/dismod.html). our estimate of pb-associated mmr presented a special challenge. pruss-ustun et al. (2004) estimated the prevalence of mental retardation and cognitive impairment from known, non-congenital causes (those mentioned above), compared values of developed and developing countries, and estimated a rate accounting for the increase of risk of mental retardation in developing countries, as follows: ar  p r  p baseline  p mr standard p mr standard where: mr = mental retardation; pr = region-specific prevalence of mr from known causes; pbaseline = prevalence of mr from known, non-congenital causes in developed countries; pmr standard = prevalence of mr according to the standard distribution of iq score; ar = adjustment ratio that lead exposure contributes to iq deficit is universally accepted, but there is no consensus on the dose response relationship (lanphear et al., 2000; moore et al., 1977; pocock et al., 1994; table 1. variables for the cost of lead abatement in nigeria. cost ($/liter) consumption unleaded 0.01 *6,837 gasoline non-pb 0.01 6,837 abatement additive refinery 0.006 1,408 factors retooling tetraethyl 0.002 6,837 lead (tel) domestic 0.16 1,408 gasoline gasoline foreign 0.16 5,429 source gasoline total 0.16 6,837 gasoline *(u.s. doe, 2000) lynn and vanhanen, 2002; stouthard et al., 1997). based on the meta-analysis conducted by popcock et al. (1994) and by schwartz (1994), we relied on the following categories defined by three levels of exposure to pb measured by blood pb content. children with relatively low blls (5 8 g/dl) suffer a 1.0 iq deficit; those with medium bll (9 15 g/dl) suffer 2.0 iq deficits, and children in the high pb exposure category (> 16 g/dl) suffer 3.0 iq deficit. pruss-ustun et al. (2004) estimated lead-induced mmr to be 0.385/1000 for sub-saharan africa (ssa) populations, compared to 0.256 per 100 people in europe. we judged this estimate to be inadequate for nigeria based on the assumption of global average iq score of 100. instead, we relied on the baseline iq estimates of lynn and vanhanen (2002) that are more localized in perspective, providing average iq scores for ssa and nigeria as 70 and 67, respectively. the present study also departs from the pruss-ustun et al. (2004) assessment in the following way. instead of extracting the fraction of lead-induced mmr from an overall mmr rate in nigeria, an estimation of the iq drop due exclusively to lead exposure was assessed on the basis of the range of measured blls and the iq decrements attributed to those ranges in the clinical literature. to estimate the burden attributable to mmr, we adopted the approach used in a dutch burden of disease study where a severity weight of 0.06 was assigned for deficits in iq between 1 4 points (stouthard et al., 1997). the proportion of disease cases attributable to pb exposure to an environmental risk factor (attributable faction) was based on miettenen’s approach (1974): afj  p(rr j  1) p(rr j  1)  1 where: af j  the fraction of burden from some cause j (lead exposure); rr j  the relative risk of disease for cause j in the exposed to unexposed group; p = prevalence of exposure. the attributable fraction was used to derive an estimate of the lead attributable burden (labd) for low, medium, and high pb exposures given relative risks (or odds ratios) for each cause of death and disability related to the exposure, levels of exposure (pre table 2. summary of blood lead levels in children, ages 1-6, otukpo. mean %>10 sex n [bpb] range sd ug/dl female 138 8.9 (2.1,23.8) 4.2 32.5 male 168 9.8 (2.2,31.8) 4.8 35.0 total 306 9.4 (2.1,31.8) 4.2 34.3 valence), and burden of disease due to each cause of death and disability in a given population: ab  afj b j where: ab = attributable burden for a risk factor; afj = fraction of burden from cause j bj = population level burden of cause j economic cost of lead exposure the u.s. epa estimated the cost of a lead abatement program to be approximately 500 million dollars per year in 1985 (usepa 1985). estimates for the cost of a lead additive (tetraethyl lead (tel), $0.002/liter), refinery overhaul ($0.006/liter), and non-lead additive (methy tert butyl ether (mtbe), $0.01/liter) were derived from thomas and kwong (2000). the average cost of gasoline in nigeria was estimated to be approximately $.16/liter (obioh et al., 2005). the annual consumption of domestic and imported gasoline in nigeria is 24,260 and 93,550 barrels per day, respectively (us doe, 2000). thus, the total consumption of leaded gasoline in nigeria is 117,810 barrels per day (table 1). schwartz (1993) estimated that $17.2 billion dollars per year would be saved by a 1  g/dl reduction in blood levels per year across the u.s. population. we used a similar approach to estimate the economic cost of lead exposure in nigeria, but with modifications that capture issues specific to nigeria and time differentials, including adjustments according to the consumer price index (cpi), and gross national income in purchasing power parity (gni-ppp) of 2.3% for the study period (population reference bureau, 2006). results and discussion blood lead levels blood lead levels measured in children of otukpo are summarized in table 2. the mean for all children was 9.4 g/dl (sd = 4.2, n = 306). the mean value for males (55% of the sample; table 3) was not significantly higher than for females. the highest bll measured was 31.8 g/dl, which is below the u.s. standard of 45 g/dl for lead poisoning treatment with chelation therapy. the proportion of children having bll above the usepa action level of 10 g/dl is more than one third. figure 1 shows a comparison of bll distribution among children residing in otukpo with previous reports of blood lead levels for children in the more urbanized city of kaduna and other distantly located cities (nriagu et al., 30 p o p u la ti o n 25 20 otukpo 15 kaduna 10 % 5 0 5 7 9 11 13 15 17 19 21 blood lead concentration (ug/dl) figure 1. blood lead levels measured in nigerian children. table 3. summary of demographic characteristics in children, ages 1 6, otukpo. characteristics percentage gender male 54.9 female 45.1 age of child 1 year 19.9 2 years 18.3 3 years 15.0 4 years 13.7 5 years 15.4 6 years 17.6 born in otukpo child 87.9 mother 42.8 father 34.6 average household size 6.8 people maternal literacy 64.7 education level mother father 0-4 years 61.5 55.6 5-8 years 17.9 21.6 9-12 years 18.2 15.0 >12 years 2.3 7.8 occupation mother father self-employed 54.6 30.9 professional 10.1 15.4 factory worker 1.0 4.9 homemaker 14.1 0.0 farmer 13.4 27.8 other 13.1 18.6 years child has lived in current residence 1 year 28.1 2 years 20.9 3 years 15.0 4 years 12.4 5 years 10.1 table 3. contd. 6 years 12.1 type of housing detached 21.2 attached 62.4 apartment 15.4 other 1.0 housing construction material brick/block 98.0 wood 0.7 other 0.7 unknown 0.7 source of drinking water pipes 29.7 public faucet 1.6 well 61.8 barrels 2.3 bottled 1.6 combination 3.0 time spent away from home by child 0 hours 84.3 1 hour 0.3 2 hours 0.7 3 hours 2.9 4 hours 2.6 >4 hours 9.4 children that wash hands 40.8 mothers that cook/store 36.0 food/water in clay pots 1997; adeniyi and anetor, 1999) . the population of kaduna is approximately 1.5 million people in 2002. the mean bll in kaduna children ages 1 6 years old is 10.6 µg dl -1 (± 3.8); with total atmospheric emissions of pb in the region being 150 tons annually, and 97% of that exposure coming from leaded gasoline (nriagu et al., 1996; obioh et al., 1988). table 3 shows a summary of the socio-demographic data that was collected through the epidemiological survey. almost 90% of the children were born in otukpo, but less than half of the parents were indigenous. the average household size was approximately 7 individuals and most lived in attached compound houses constructed of cement bricks with groundwater wells being the source of drinking water. mean bll was significantly associated with household size, maternal literacy, parental occupation, home floor type, time spent outside the home, residential proximity to a ceramics shop, and by parental employment in a print shop (p<.05), but not with age, parental education, housing construction type or detachment status, drinking water, and frequency of hand-to table 4. deaths (x1000) and dalys (x1000) from all pb-linked diseases for males and females, ages 0-14. deaths, 0-14 dalys, 0-14 pb-disease category male female male female genito-urinary disease 16 13 710 541 prematurity* 384 384 2,295 2,295 dental caries 0 0 129 127 nervous system cancers 7 6 270 210 congenital anomalies 32 33 2,455 2,628 hypertension** 2 2 66 69 cerebrovascular disease 9 9 313 298 pb-mild mental retardation (mmr) 0 0 2,463 2,414 low birth weight*** 262 234 9,827 8,873 sub-saharan africa (ssa) 712 681 18,528 17,455 ssa,m&f 1,393 35,983 nigeria 121 116 3,150 2,967 nigeria, m & f 237 6,117 *dalys calculated using dismod with incidence rates from (antilla et al., 1995). **daly data from type i diabetes, ***low birth weight is the largest category within perinatal conditions table 5. pb-linked burden of disease percentages (bdpb%). deaths dalys male female male female pbbd% of ssa 2.42 2.75 1.82 2.04 pbbd% of ssa, 0-14 4.57 5.31 2.97 3.34 pbbd% of ssa, 0-14, m/f 4.90 3.14 pbbd% of nigeria 14.25 16.18 10.71 11.99 pbbd% of nigeria, 0-14 26.86 31.25 17.48 19.67 pbbd% of nigeria, 0-14, m/f 29.06 18.58 mouth behavior (ogunseitan and smith, submitted). lead-associated burden of disease estimates table 4 shows the results for overall deaths and dalys by gender for children, ages 0-14, of sub-saharan africa (ssa) and nigeria. table 5 shows the results by gender for lead-linked disease burden for children in nigeria. the data are shown as a percentage of ssa burden, ssa childhood burden, nigerian burden, and nigerian childhood burden. table 6 shows the medium estimate for dalys of all nine disease burden categories by gender for children, ages 0-14, for both ssa and nigeria. also, the ors that were found in the literature are shown. the three exposure categories are classified as low exposure (5-8 g/dl), medium exposure (915 g/dl), and high exposure (>16 g/dl). there is no or for lead-attributed mild mental retardation (mmrpb) required, because by definition, 100% of mmrpb is due to lead exposure. table 7 shows the medium estimate of both the attributable risk and attributable burden for lead exposure across all three exposure categories for children, ages 0 14, in ssa and nigeria. also, the pb-attributed burden of disease (bdpb) is shown as a percentage of the total nigerian bd, and the total nigerian childhood bd. nigerian childhood blls of 5 8 g/dl account for approximately 2.18% of the total nigerian childhood burden, blls of 9 15 g/dl account for 7.50%, and blls >16 g/dl account for 5.07%. combined all lead exposure accounts for approximately 14.74% of the total nigerian childhood disease burden. health costs of lead (pb) exposure the estimates of childhood health costs of lead exposure are outlined in table 8. the total costs are presented in millions of dollars. while all of the sub-categories (medical, compensatory education, lost earnings, imr, and neonatal care) show significant health costs of pb expos table 6. dalys and odds ratios for 9 pb-linked diseases (medium estimate). pb-disease category dalys, 0-14 or @ 3 pbb levels* male female total 5-8 9-15 >16 genito-urinary disease 710 541 1251 1.0 1.9 3.8 1 prematurity 2295 2295 4590 2.2 4.3 8.6 2,3 dental caries 129 127 256 6.8 9.6 4 13.5 4 nervous system cancers 270 210 480 2 5.5 5 11.0 5 congenital anomalies 2455 2628 5083 1.0 1.6 3.2 6 hypertension 66 69 135 1.0 1.5 7 3 cerebrovascular disease 313 298 611 2.2 8 4.5 8 6.8 8 pb-mild mental retardation 2463 2414 4877 n/a n/a n/a low birth weight 9827 8873 18700 1.2 2.4 4.7 9 total ssa 18528 17455 35983 total nigeria 3150 2967 6117 *blls are presented in ug/dl. not all the odds ratios were available for all three blood lead levels in every disease category. estimates were used in those cases. 1 (antilla et al., 1995) 2 (asien et al., 2000); 3 (khera et al., 1980); 4 (gemmel et al., 2002); 5 (landrigan et al., 1976) 6 (kristensen et al., 1993) 7 (factor-litvak et al., 1996) 8 (gomaa et al., 2002) 9 (kristensen et al., 1993). table 7. attributable risks and attributable burden for 9 pb-linked diseases (medium estimate) ar for pbb levels *ab for pbb levels pb-disease category 5-8 9-15 >16 5-8 9-15 >16 genito-urinary disease 0.0 33.5 21.9 0 419 274 prematurity 29.0 64.9 43.2 1,330 2,978 1,982 dental caries 6.8 9.6 13.5 17 25 35 nervous system cancers 25.4 71.6 50.0 122 344 240 congenital anomalies 0.0 25.1 18.0 0 1,278 917 hypertension 0.0 21.9 16.7 0 30 23 cerebrovascular disease 29.0 66.2 36.7 177 405 224 pb-mild mental retardation 100.0 100.0 100.0 1,609 1,609 1,609 low birth weight 6.4 43.9 27.0 1,191 8,218 5,050 total ssa 4,446 15,306 10,353 total nigeria 756 2,602 1,760 % nigeria bod attributable to pb 1.40 4.80 3.25 % nigeria bod, attributable to pb (0-14) 2.18 7.50 5.07 *attributable burden is presented in dalys (x1000) ure, lost earnings and increased imr appear to have the largest impact on overall cost. the total childhood health cost was estimated to be $10.3 billion ($238 million gni ppp adjusted), or 29.8 billion naira annually for a 1 g/dl increase in bll. considering that the average bll in nigerian children is approximately 10 g/dl, the cost of lead exposure could be ten times higher than what is reported here. thus, if nigeria is able to decrease national bll average by 5 g/dl, the country could gain more than $1 billion in savings annually from childhood health costs. table 9 shows the results for the adult health costs of lead exposure. the total health costs are presented in millions of dollars. mortality costs of hypertension–related deaths provide the driving force behind the bulk of the adult health costs, accounting for $6.6 billion out of $7 billion (94%) estimated for total adult health costs. table 10 shows the estimates for the total health cost annually for the entire population. it also provides the annual per capita health cost of lead exposure, the annual health cost as a percentage of gni-ppp, and the annual health cost as a percentage of the average per capita health ex table 8. childhood health costs of lead exposure. children variable $(m) gni-ppp adjusted million naira average blood lead concentration 9.8 ug/dl number of children requiring 160,909 medical costs chelation therapy cost of chelation therapy 1,920 total medical costs 309 7 888 number of children who receive 162,231 compensatory education education cost of education 4,902 total compensatory education 795 18 2,286 cost number children, age 6 3,515,600 earnings increase in earnings of a 1 ug/dl 1,920 reduction in bll total earnings lost 6,750 155 19,406 imr 75/1000 1 ug/dl reduced maternal blood – 74.9/1000 imr infant mortality value of statistical life 4,429,840 number of live births in nigeria, 5,192,000 2002 number of reduced deaths 519 total imr cost 2,299.09 52.88 6,609.88 # of nicu admissions 1,752,300 reduced nicu admissions 1,749,960 neonatal care number of fewer nicu admissions 2,340 cost of nicu 86,661 total neonatal cost 202.79 4.66 583.01 total childhood cost 10,356.03 238.19 29,773.58 expenditure. all of these health cost figures are for a 1 g/dl change in bll. the total health cost is presented as a low, medium, and high value. the low value was calculated by subtracting the cost of compensatory education and nicu from the total. it is hypothesized that nigeria could have significantly less compensatory education than the united states for children who are academically challenged. likewise, the frequency of children admitted into nicu in nigeria could be much lower than the us. based upon these assumptions, the low estimate for the health costs due to lead exposure is estimated to be approximately $377 million. the high value for health costs due to lead exposure was taken from landrigan et al. (2002) who estimated that the health costs due to lead exposure for the cohort of children born in 2000 is approximately $43.4 billion (usd, 1997). this estimate was adjusted using both the consumer price index (cpi) and the gni-ppp ratio between the us and nigeria (2.3%). the resultant health cost estimate after allowing for these adjustments is approximately $1.15 billion. cost of lead abatement table 11 illustrates the cost of a lead abatement program in nigeria. the cost is a combination of four subcategories: the cost the refinery upgrades, the cost of a nonlead additive, the cost of unleaded gasoline, and the cost of tel. these sub-category costs are presented in $/liter. to calculate the overall cost of the abatement program, the cost of tel is subtracted from the summed costs of refinery upgrades, non-lead additive, and unleaded gasoline. using the national gasoline consumption provided by the department of energy (doe), the medium overall estimated cost of a lead abatement program for nigeria is approximately $194 million for the first year. this is approximately 48.5% of the health cost of a 1 g/dl increase in bll per year g/dl. the low estimate, using the low estimate cost of $0.01 /l reported by the organization for economic development (oced) for lead phase out is $76 million per year (11). the high estimate, using the high estimate cost of table 9. adult health costs of lead exposure. adults variable $(m) gni-ppp adjusted million naira medical costs number of cases of hypertension 288,712 hypertension annual medical costs 812 total medical cost 234.43 5.39 674.00 number of cases of heart attacks 1,454 heart attacks medical costs 33,960 total medical cost 49.38 1.14 141.96 number of cases of stroke 591 strokes annual medical costs 26,574 total medical cost 15.71 0.36 45.15 lost wages number of cases of hypertension 288,712 hypertension annual lost earnings 115.0 total earnings lost 33.20 0.76 95.46 number of cases of heart attacks 1,454 heart attacks annual lost earnings 31,000 total earnings lost 45.07 1.04 129.59 number of cases of stroke 591 strokes annual lost earnings 17,716 total earnings lost 10.47 0.24 30.10 number of deaths 1,500 mortality value of statistical life 4,429,840 total mortality cost 6,644.76 152.83 19,103.69 total adult cost 7,033.02 161.76 20,219.94 table 10. total health costs of lead exposure. $m gni-ppp † million low estimate (2003) adj. $m naira total annual health cost to nigeria of 1 g/dl bpb *16,391 377 47,124 annual per capita cost 126 2.90 362 annual cost as percentage of gni-ppp 0.36% 0.36% 0.38% annual cost as percentage of per capita health expenditures 14% 14% 14% medium estimate total annual health cost to nigeria of 1 g/dl bpb 17,389 400 49,993 annual per capita cost 134 3.08 385 annual cost as percentage of gni-ppp 0.38% 0.38% 0.38% annual cost as percentage of per capita health expenditures 15% 15% 15% high estimate total annual health cost to nigeria of 1 g/dl bpb **49,810 1,145 143,203 annual per capita cost 383 8.81 1,102 annual cost as percentage of gni-ppp 1.10% 1.10% 0.38% annual cost as percentage of per capita health expenditures 44% 44% 44% *low estimate = total health costs – cost of compensatory education and nicu. **high estimate = ($43.4 billion) (cpi, 2003), (49). † million naira. table 11. cost of lead abatement in nigeria. cost ($/liter) ‡ cons. (10 6 cost (m$/yr cost (m$/yr cost l/year) 1995) 2003) ( † mn/yr, 2003) unleaded gasoline 0.01 6,837 68 82 10,250 abatement factors non-pb additive 0.01 6,837 68 82 10,250 refinery retooling 0.006 6,495 39 47 5,875 tetraethyl lead (tel) 0.002 6,837 14 17 2,125 domestic gasoline 0.16 6,495 1,039 271 33,821 gasoline source foreign gasoline 0.16 342 55 66 8,250 total gasoline 0.16 6,837 1,094 1,313 164,148 low estimate total annual cost of abatement *75.6 24,250 pb abatement cost / pb health cost 0.189 0.189 abatement as % of health cost 18.9% 18.9% medium estimate total annual cost of abatement 194 24,250 pb abatement cost / pb health cost 0.485 0.485 abatement as % of health cost 48.5% 48.5% high estimate total annual cost of abatement *227 24,250 pb abatement cost / pb health cost 0.567 0.567 abatement as % of health cost 56.7% 56.7% *low estimate = ($.01/l) (liters consumed/year) (11). **high estimate = ($.03/l) (liters consumed/year) (11). ‡ consumption, † million naira. $0.03/l reported by oecd, is $227 million per year (oecd, 1999). in conclusion, we have shown that lead exposure remains a major health risk factor in all nigeria communities, both rural and urban. the most important – and controllable – source of exposure is leaded automobile fuels. arguments based on the enormous costs to society of switching to unleaded fuels are weak in the face of counterarguments based on the even more astounding health care and special educational costs associated with lead exposure. in the presence of alternative renewable fuels such as ethanol (thomas and kwong, 2000), the removal of lead from all fuels in nigeria – and all countries in sub-saharan africa – should not be delayed a single day further. acknowledgments this study was supported in part by funding and resources provided by the global forum for health research, switzerland; by the u.s. centers for disease control and prevention; and by the u.s. national science foundation (cms-0524903). additional support was provided by the program in industrial ecology at uc-irvine. we are grateful for the kind support provided by dr. sunday ochenjele at mount zion hospital, otukpo; and by shime-nenge imadu, secretary of the ethical committee of the ministry of health and human services, benue state, nigeria. references adebamowo eo, agbede oa, sridhar mkc, adebamowo ca (2006). an examination of knowledge, attitudes and practices related to lead exposure in south western nigeria. bmc public health 6 (82): 1–7. ademuyiwa o, ugbaja rn, idumebor f, adebawo o (2005). plasma lipid profiles and risk of cardiovascular disease in occupational lead exposure in abeokuta, nigeria. bmc lipids in health and disease, 4(19): 1–7. adeniyi faa, anetor ji (1999). lead poisoning in two distant states of nigeria: an indication of the real size of the problem. afr. j. med and med. sci. 28: 107-112. agency for toxic substances and disease registry (1999). toxicological profile for lead (update). us department of health and human services, atlanta, georgia. anttila a, heikkila p, pukkala e, nykyri e, kauppinen t, hernberg s, hemminki k (1995). excess lung cancer among workers exposed to lead. scan j wrk environ. health, 21(6): 460-469. asien ao, olarewaju rs, imade ge (2000). twins in jos, nigeria: a seven year retrospective study. med. sci. monit. 6(5): 945-950. charney, e. 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(1990) logarithmic relation can sufficiently describe wind profile over sea during adiabatic condition. however, when the sensible heat flux and latent heat flux are significantly different from zero, stability correction should be made. such stability correction can be calculated using the diabatic method to account for change in temperature and moisture associated with sensible and latent heat flux. we compare potential energy generation using power law relationship and diabatic evaluation method to determine the suitability of each method for nigerian coastal wind estimation. in this paper we demonstrate the suitability and potential of some coastal stations in nigeria for wind energy production. this is motivated by the fact that there is no wind farm presently in nigeria, at least, in table 1. power law exponent p value at various stability categories. stability category a b c d e f z0 = 1 0.17 0.17 0.20 0.27 0.38 0.61 commercial use. therefore there is need to evaluate the potential of some locations to determine their suitability for wind power generation. data and method monthly wind data over some coastal stations (lagos, calabar) constitute the major data for this study. 18 years data between 1991 and 2008 were obtained from the archives of the nigeria meteorological agency (nimet) oshodi lagos. the wind speeds measured at the reference height of 10 m were used to calculate the wind speed uz at heights between 15 and 70 m at the interval of 5 m. the power law relationship is given as; z 2 p u z [1]  u 1 z 1 the exponent p of the power law varies with stability categories according to irwin (1976b) as shown in table 1; further explanation is given in table 2 according to turner (1994). equation [1] was used to estimate wind speed from reference height of 10 to 70 m. on the other hand, to estimate wind speed using diabatic method, we start from the monin – obukhov (m-o) similarity theory which relates the mean gradient of wind speed, temperature and humidity to the universal function of dimensionless stability parameter z l . the gradient functions are, as given by large and pond (1982); kz u  m  z l [2] u* z kz   t  z l [3] * z kz q  q  z l [4] q* z where u ,  , q are the wind speed, the absolute temperature and absolute humidity respectively. the quantities u* , * and q* are friction velocity, temperature scale and humidity scale respectively. absolute temperature profile is approximated by   tair  0.01z and l is given by;   u*  2 tv l [5] kg *v where tv the absolute virtual temperature, g is the acceleration due to gravity and *v is the virtual temperature scale. integration of equations 2 to 4 gives the profile function for wind speed, temperature and humidity. for wind speed, the profile function can be written as; u * z z m u z  [6] ln k z 0 l von karman constant (k = 0.40), z and z0 are the height of wind speed and roughness length respectively. the costal of nigeria can be characterized as regularly covered with large obstacles with open spaces roughly equal to obstacle heights, sub – urban houses, village and mature forest. following the devenport – wieringa roughness classification (wieringa, 1981) z0 has been taken as 1.0 m. in the present case, it required to calculate the wind speed u 2 at a specific height z2 , given the wind speed u1 at the height z1 , thus equation 6 can be rewritten as; z2 z1 u u z2  z1  [7] ln ln 2 1 z 0 m l z 0 m l where  m is the stream function given as, for unstable condition (l<0); 1 x 2 1 m 1 x x  2 [8]  2ln  2tan  ln 2 2 where x  1 16z l1 4 for stable condition  m 5z l for simplicity, l values have been carefully chosen for unstable (l<-200) and stable (l>200) (van et al., 1990) atmospheric table 2. pasquill – gifford stability categories. stability category classification natural phenomena most likely occurrence extremely a unstable moderately b unstable c slightly unstable d neutral e slightly stable f moderately stable strongly thermal instability transitional periods, moderate mixing transitional periods, slight mixing strong winds, overcast day/night transitions transitional periods, night time, moderate winds clear night-time skies, very limited vertical mixing, plume planning and meandering late morning to mid afternoon in spring and summer dry time transitions, all year day time transitions, all year day time, cloudy; high winds; day time transitions, all year night-time transition, all year night, clear skies, light winds, all year conditions and then, equation 7 was used to construct while in august and september it is down to 75 mm (3 diabatic wind profile from 10 to 70 m at interval of 5 m. the inches) and in january as low as 35 mm (1.5 inches). the wind power relation was obtained as, (stull, 2000); main dry season is accompanied by harmattan winds from the sahara desert, which between december and early p  1 u 3 february can be quite strong. the average temperature in [9] january is 27°c (79°f) and for july it is 25°c (77° f). on 2 average the hottest month is march; with a mean temperature of 29°c (84°f); while july is the coole st month where p ,  and u are respectively wind power, air (bbc, 2010). calabar is similar to the lagos in terms of the climate, density and wind speed. wind energy potential was during the winter months of november to march, which are computed by integrating estimated power using trapezoidal usually referred to as the dry season in nigeria, there could method. be occurrence of harmattan dust haze in calabar but the frequency is very low. this means that winds over calabar climate of the study area are predominantly south – westerly. in summer, (wet season), the patterns of precipitation are typical of the lagos has a tropical savanna climate (köppen climat e equatorial zone (adefolalu, 1984). classification aw) that is similar to that of the rest of southern nigeria. there are two rainy seasons, with the results heaviest rains falling from april to july and a weaker rainy season in october and november. there is a brief wind speed – height structure relatively dry spell in august and september and a longer dry season from december to march. monthly rainfall it is important to state here that the focus of this between may and july averages over 300 mm (12 in), study is on the two extremes of stability category for easy comparison between the diabatic and power law methods; hence we will not duel on other stability categories that transit between the extremes (table 2). wind speeds with heights were estimated using the power law relationship for extremely unstable and moderately stable conditions as presented in figure 1. these two conditions were estimated from average monthly wind speeds between 1991 and 2008 at reference height of 10 m, thus the wind speed converges at this height. under the stability category f (moderately stable), estimated wind speeds over lagos increased up to 21 m/s at height 70 m whereas in the category a (extremely unstable) wind speeds at the same height was just about 8 m/s. greater wind speeds are best achieved under the category a stability criterion, this condition is prevalent in the night time. over calabar, greater wind speeds estimate was also 20 18 (m /s ) 16 14 s p e e d 12 10 w in d 8 6 4 2 0 jan fe b m ar apr m ay jun jul aug se p oct nov de c m onth 18 16 (m /s ) 14 12 sp ee d 10 w in d 8 6 4 2 0 jan feb mar apr may jun jul aug sep oct nov dec month unstable stable unstable stable figure 1. variation of calculated mean monthly wind speeds in lagos (upper panel) and calabar (lower panel) using power law relationship. achieved under the category f stability classification, however, the wind speeds estimated were lower than the values obtained over lagos. thus, lagos is generally windier than calabar based on the 18 years of data considered for this study. the diabatic estimation for both stable and unstable atmospheric condition over lagos shows that wind speeds increased with height up to 18 m/s for stable condition at height of 70 m and up to 15 m/s for unstable condition, which is similar to the wind – height structure obtained over calabar (figure 2), however, wind values over calabar are lower than values over lagos. the value for the stable condition using diabatic method is lower than the value obtained from power law. in diabatic method a number of parameters were included in the estimation of wind speeds such as the roughness length, which puts into consideration the actual features (obstacles, building) of the site that are capable of obstructing free flow of wind. since power law does not include this consideration, the estimation from power law is unrealistically high especially in stable conditions. thus for estimate of wind speed in stable conditions, diabatic 12 (m /s ) 10 stable 8 s p ee d 6 w in d 4 2 unstable 0 jan fe b m ar apr m ay jun jul aug se p oct nov dec m onth 10 9 (m /s ) 8 stable 7 s p ee d 6 5 w in d 4 3 2 1 0 unstable jan feb mar apr may jun jul aug sep oct nov dec month figure 2. variation of calculated mean monthly wind speeds in lagos (upper panel) and calabar (lower panel) using diabatic method. method provides a better approximation. seasonal characteristics of wind speed at height 70 m the most effective wind in terms of energy generation is the wind located at the height of the turbine blades. for this investigational purpose, the height 70 m is considered as this is the average height of turbine blade in most of commercial wind farms (icreed, 2006), 80 m is the current industry norm which is based on wind turbines at 70 m. in figure 3 the seasonal variation of wind at height 70 m is presented. over lagos, wind speeds estimated using the power law depict a wide difference between unstable and stable conditions. wind speeds are always higher in stable condition than unstable. the observation over calabar is similar to that obtained over lagos. however, using the diabatic method, the difference between wind speeds estimate under the stable and unstable conditions was not much. the wide difference in the case of power law may have been due to weakness inherent in the method (for example, it does not include the effect of building and other friction – causing obstacles). despite the shortcomings, the method has shown that there are stronger wind speeds during the stable condition than unstable condition. 18000 stable unstable 16000 14000 (j o u le s ) 12000 10000 e n e rg y 8000 6000 4000 2000 0 jan r y jul ep ov a ma m s n m onth 10000 stable unstable 9000 (j o u le ) 8000 7000 e n e rg y 6000 5000 4000 jan mar m l s p nov u y a j e m onth figure 3. variation of mean monthly energy for lagos (upper panel) and calabar (lower panel). maximum energy occurs in august and march in lagos and calabar respectively. diabatic method also revealed similar deduction. stronger wind speeds occur during the stable condition due to the thermal stratification of the atmosphere. a statically stable atmosphere will offer less friction and enhance wind speeds than unstable, mixed atmosphere. since stable condition often occur in the night, it is envisaged that more power will be generated from the wind turbine during the night. the seasonal variation of wind speed at 70 m over lagos using both methods shows a generally increasing speed from january to april. it decreases thereafter to december except in august when there was slight increase. this pattern was followed over calabar. the months of march and april, when wind speeds were highest are months of transition between the dry and the wet season over the coastal stations, which are usually characterised by strong winds. as soon as the wet season starts properly, weak winds take over. this explains the seasonal characteristics of the wind speeds as noted earlier. thus power generation will peak during the months of march and april. the august slight increase in wind speed may be due to the characteristic of ‘little dry season’ that (usually) occurs during the month. comparing seasonal wind estimation from both power law and diabatic methods, it is observed that power law method slightly overestimate wind speeds. this can be understood from the fact that power law does not consider the friction effects usually offer to wind table 3. power generation stations in nigeria showing the peak and off peak supply. note that there is no wind turbine. station turbine peak gen (mw) off peak gen (mw) kainji hydro 237 204 jebba hydro 435 368 shiroro hydro 408 egbin steam 850 785 trans amadi gas 20.1 a.e.s gas 250 249.3 sapele steam 138 144 ibom gas 81.6 4.3 okapi gas 425 380 afam 1-5 gas 59 60 afam vi gas 299 302 delta gas 200 205 geregu gas 387 260 omoku gas 40.2 12.1 omotosho gas 25.2 25.2 olorunsogo phase i gas 42.3 20.3 olorunsogo phase ii gas 121.6 total 3877.4 3160.9 source: national mirror, 13 april, 2011. speed by building and trees. for example, over lagos in august, power law estimated a wind speed of about 18 m/s where in the same month, using diabatic method, the wind speed was about 11 m/s. this can be misleading especially when deciding the specification of wind turbine needed at these sites. thus, correct estimation is better done using the diabatic method. monthly pattern of wind energy potential over the stations accurate estimation of wind speeds at the desired heights can help in forecasting the likelihood of power generation from a wind farm. using the estimated wind speed at 70 m, expected energy output for lagos and calabar are shown in figure 3. the energy outputs for both stations were calculated from the wind estimated using diabatic method only (for obvious reason). following the monthly gradual increase in wind speeds from january to april, the energy potential of the wind speeds also increases in both stations. however, the drop in energy potential in june / july was shaper over calabar than lagos, suggesting that within these months energy realisation in a potential wind farm located in lagos will be more than in calabar. the highest peak of energy generation from wind over lagos occurs in august at about 16000 joules under stable condition. the peak energy reduces to about 14000 joules under unstable condition. over calabar the peak energy occurs in february / march amounting to about 9000 and 8000 joules under stable and unstable conditions respectively. discussion the nation’s power generation hit 4,000 mega watts (mw) at the beginning of 2011 according to the data released by the power holding company of nigeria (phcn) in the first quarter of the year, power generation increased from 3,800 mw to 4,000 mw. the improvement according to the data was achieved as a result of increased water level of hydroelectric power stations located at kainji, jebba and shiroro (national mirror, 2011). the commencement of operation by the independent power plant (ipp) stations over some new locations contributed to the improvement recorded during the period (national mirror, 2011). despite this improvement, power supply in nigeria remains epileptic as there are no 24 h uninterrupted power supply, even to industrial areas. it is noted from table 3 that there is yet no wind power harnessed for the purpose of generating electricity in nigeria. a unit turbine will produce at least 191.11 kw of electricity per hour, in the coastal stations of lagos and calabar, the average wind speed is about 9.0 m/s at 70 m, which translate to 478 kw of electricity at 100 % efficiency, if power is cube of wind speed. assume the wind turbine is operating at 40% efficiency; a wind farm of 5,000 units will generate about 995 mw. having at least five wind farms will increase the supply by at least 4,775 mw, which is more than what all existing sources in nigeria are generating (table 3). it is important to consider another source of power generation to meet the demand for electricity supply. wind energy, which remains hitherto untapped, appears promising in solving the problem of electricity shortage. apparently, wind energy potential is exploitable in nigeria, along the costal towns where stronger wind speeds are sufficiently available throughout the year. analysis presented in this study showed that night time stable condition produces stronger wind speeds. at night time, or when the atmosphere becomes stable, wind speed close to the ground usually subsides whereas at turbine hub altitude it does not decrease that much or may even increase. as a result the wind speed is higher and a turbine will produce more power than expected from the 1/7th power law: doubling the altitude may increase wind speed by 20 to 60%. a stable atmosphere is caused by radiative cooling of the surface and is common in a temperate climate: it usually occurs when there is a (partly) clear sky at night. when the (high altitude) wind is strong (a 10 m (33 ft) wind speed higher than approximately 6 to 7 m/s (20 to 23 ft/s)) the stable atmosphere is disrupted because of friction turbulence and the atmosphere will turn neutral. a daytime atmosphere is either neutral (no net radiation; usually with strong winds and/or heavy clouding) or unstable (rising air because of ground heating — by the sun) . here again the 1/7th power law applies or is at least a good approximation of the wind profile. indiana (usa) had been rated as having a wind capacity of 30,000 mw, but by raising the expected turbine height from 50 m to 70 m, the wind capacity estimate was raised to 40,000 mw, and could be double that at 100 m. conclusion two methods (power law relationship and diabatic) have been used to determine the wind energy potential of two stations located along the coast of nigeria. the coastal areas are usually windy and they provide suitable location for wind farm. comparing the two methods, wind speeds estimated from diabatic method for both stable and unstable atmospheric conditions appear to be more accurate due to certain physical condition built into the method. for example, diabatic method which considered the effects of building and obstacles that offer resistance to wind is more realistic than power law which makes no assumption about physical appearance of potential wind farm locations. furthermore, power law relationship shows a wider deviation from reality under unstable atmospheric condition. these unavoidable weaknesses in power law may lead to erroneous energy calculations. thus, diabatic method of wind speed estimation is suitable when in situ measurements are not available at the desired heights. analysis in this study has shown that nigerian coastal stations are good potential areas for wind farms. the coastal stations have an average wind speed of 9 m/s are capable of generating about 995 mw of electricity in a single farm of 5,000 unit of wind turbine. five such farms will produce as much as the present power generation in nigeria with all source put together. this alone puts wind 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(2010). http://www.bbc.co.uk/weather/world/city_guides/city.shtml?tt=tt0005 10. retrieved 2010-06-02. weiringa j (1981). estimation of mesoscale and local scale roughness for atmospheric transport modeling. proceedings from the 11 th international conference on air pollution modeling and its application, november, 1980, amsterdam, netherlands, plenum press, new york, pp. 279–295. in ternationa l scholars journa ls african journal of environmental economics and management issn 2375-0707 vol. 6 (1), pp. 384-393, january, 2018. available online at www.internationalscholarsjournals.org © international scholars journals author(s) retain the copyright of this article. review an assessment of the effectiveness of water management in south africa *candice barnard, justin shuttleworth and mark c. verwoerd civil and chemical engineering department, university of south africa – unisa, corner christian de wet road and pioneer avenue, florida, private bag x6, 1710, florida campus, johannesburg, south africa. accepted 12 october, 2017 in south africa, there are many challenges regarding water management. inadequate rainfall, may contribute to mismanagement, hence political breakdowns and racial groups do also contribute to the problem. to list some of the major challenges for effective management are: limited physical resources, a long cycle of inadequate rainfall, a rapid growing population, and stagnant economies. water resource management is crucial for human security. in south africa, almost everyone is affected by mismanagement of water resource, hence those living in poor area are the most affected as they do not have access to potable water and proper sanitation. many policy-makers, researchers, and water managers advocate that water must be managed at the level of river basins, based on the argument that river basins are a ‘‘natural’’ unit and thus the logical unit for water management. although stakeholder participation in water management is advocated, actually including the poor and achieving substantive stakeholder representation has proven elusive in practice. more often than not, participation is little more than token consultation, with no decision-making power in the hands of the people concerned? too often, the participation discourse draws attention away from the very real social and economic differences between people and the need for the redistribution of resources, entitlements, and opportunities. this is typified by the definition of stakeholders as water. key words: water, management, resources, stakeholder, population, economy. introduction water may be everywhere, but its use has always been constrained in terms of availability, quantity and quality (biswas, 2004). the scarcity of water globally has lead to intense political pressures, often referred as “water stress”. furthermore, water problems not only involve political boundaries but, it also evades institutional classification and eludes legal generalization (wolf, 1999). many challenges regarding water management continue to face the world. some of the primary difficulties may include: limited physical resources, a long cycle of inadequate rainfall, a rapid growing population, and stagnant economies. complex challenges such as these dictate a critical need to manage and conserve water resources properly (christopher, 1988). *corresponding author. e-mail: barnard.cad@yahoo.co.uk in order to adapt to water shortages, some changes are needed that will maintain or improve the ability of a system such as the municipal water supply to continue to serve its function (ivey et al., 2004). hence, problems relating to water are neither homogenous, nor constant or consistent over time. they often vary from one region to another, even within a single country, from one season to another, and also from one year to another (biswas, 2004). solutions to water problems depend not only on water availability, but also on many other factors such as: the processes through which water is managed; competence and capacities of the institutions (private and government) that manage them; prevailing socio-political conditions that dictate water planning; development and management processes and practices (ivey et al., 2004; biswas, 2004); supply management (ivey et al., 2004) appropriateness and implementation status of the existing legal frameworks; availability of investment candice et al. 385 funds; social and environmental conditions of the countries concerned; levels of available and usable technology; national, regional and international perceptions; modes of governance including issues like political interferences, transparency, corruption, etc.; educational and development conditions and status; quality and relevance of research that are being conducted on the national, sub national and local water problems (biswas, 2004). the current trends indicate that water problems will continue become more and more complex conflicting or interfering with other developmental sectors such as energy, agriculture, mining, transportation and communications and with social sectors including education, environment, health, rural and regional development (biswas, 2004). in addition, water demands are increasingly due to population growth, groundwater levels are dropping down, surface water supplies are increasingly contaminated and becoming threats to living beings, delivery and treatment infrastructures are aging (wolf, 1999). according to the world bank, it was estimated that it would take about $600 million dollars to repair and improve the world’s existing water delivery systems. impact of climate chance on water availability access to potable water, sanitation and water for irrigation is already a serious problem in developing countries and is expected to even become more as population growth and climate change exacerbates existing inadequate delivery systems and dysfunctional management institutions. it stands to reason based on the predictions that water resources will be among the most affected sectors by change in the climate. when coupled with population growth and serious economic circumstances, climate change is an additional, highly uncertain and variable factor that exacerbates the difficulties in developing nations (stachiv and pietrowsky, 2009). climate change has many uncertainties, but generally, climate change can cause temperature increases, intensity of precipitation, storms, droughts and extreme events, change in average precipitation are less certain but will become more erratic and shifting season (heath et al., 2010). studies have shown that greenhouse warming will have major impacts on water resources and a s a results water scarcity is expected to become an ever-increasing problem in the future for various reasons. first, the distribution of precipitation in space and time is very uneven, leading to tremendous variability in water resources worldwide (oki et al., 2006). for example, the driest place on earth, the atacama desert in chile receives very slight annual quantities of rainfall each year while on the other hand; mawsynram, assam, india receives over 450 inches of rainfall annually. if all the freshwater on the planet were divided equally among the global population, there would be 5,000 to 6,000 m 3 of water available for everyone, every year (vorosmarty, 2000). second, the rate of evaporation varies depending on the temperature and relative humidity, which impact the amount of water available to replenish groundwater supplies. the combination of shorter duration but more intense rainfall combined with increased evapotranspiration and increased irrigation is expected to lead to groundwater depletion (konikow and kendy, 2005). possible impacts that may affect water planning and project evaluation include; change in precipitations and runoff patterns, sea level rise and land use and population shift may follow from the effects, warmer temperature will accelerate hydrologic cycles altering precipitation, the magnitude and timing of runoff, and the intensity and frequency of flood and droughts. higher temperature will also increase the evapotranspiration rates and alter soil moisture and infiltration rates (frederick and major, 1997; sullivan and huntingford, 2009). climate change will impact water quality by: 1) increasing extreme precipitation and flooding, which will increase erosion rates and washing soil based pollutants and toxins into waterways. 2) contaminating coastal surface and groundwater resources due to sea level rise, resulting in saltwater intrusion into rivers, deltas, and aquifers. 3) increasing water temperatures, leading to more algal and bacterial blooms that further contaminate water supplies. 4) contributing to environmental health risks associated with water. for instance, changes in precipitation patterns are likely to increase flooding, and as a result mobilize more pathogens and contaminants (pacific institute and united nation global impact, 2009). water management in south africa since 1994, the south african government has undertaken important reforms aiming to address rural poverty and inequalities inherited from the past apartheid regime. amongst other programs, it has adopted a new water legislation that promotes equity, sustainability, representatively and efficiency through water management decentralization, new local and regional institutions, water users’ registration and licensing, and the emergence of water rights’ markets (perret, 2002). the progressive south african water law (rsa, 1998) is expected to bring about fundamental changes in the way in which water is used and shared among different users. a major aim is to ensure a better balance between efficiency, sustainability and equity needs in water allocations (levite et al., 2003). water must be guaranteed for all, especially to meet the basic human 386 afr. j. envir. econ. manage. table 1. water access and usage among racial groups. groups poverty rate of individuals (%) percentage shares of population poor individuals blacks 54.8 80.1 93.3 coloured 34.2 8.7 6.3 indians 7.1 2.5 0.4 whites 0.4 8.6 0.1 all 47.1 100.0 100.0 needs of poor people in rural areas who have been disadvantaged for so long. furthermore, water cannot be simply allocated to meet the increased demand from agriculture, industry and other productive sectors but must also satisfy the requirements of aquatic ecosystems and the ecological reserve. finally, responsibility for decision-making in respect of water allocations will be decentralized to the level of the future catchment management agencies (cmas). a system of authorizations for water abstractions is foreseen with compulsory licensing when the basin is water stressed (levite et al., 2003). rural poverty the legacy of discrimination policies south africa is a lower middle-income country in which agriculture accounts for a particularly low share of gdp compared to most other countries of its category. although it has a well-performing commercial sector, agriculture represents less than 4% of gdp and 14% of the labor force (perret, 2002). moreover, irrigated agriculture and stock watering use about 52% of total water usage (table 1). the rural population of south africa is composed of approximately 1.5 million households living on commercial farms (mainly white) and 2.3 million households living in the former homelands. approximately half the country’s population lives in rural areas, and poverty rates are higher there than elsewhere. poverty is race-related (table 1). three out of five children in south africa live in poor households. households headed by women are more likely to live in poverty than households headed by men (perret, 2002). these persistent traits have several causes of which some are directly derives from the past apartheid policy. it excluded black people from owning or renting land outside the country that was delineated as reserves. moreover, today, land still remains mostly state-owned, and is granted to users through traditional authorities and regulations. these areas are typically poor rural areas, where many people live under conditions of deprivation as harsh as elsewhere in poorer african countries. apartheid involved incentives, laws and institutions that favored large farms and discriminated against smaller, labor intensive farming systems (perret, 2002). apartheid also gave large white farms privileged access to natural resources, financial and agribusiness facilities, and rural infrastructures. water resource scarce and unevenly distributed south africa is a water scarce country, due to its low average annual precipitation, and the unevenness of surface and groundwater distribution which is a result of climate and geography and only 8.6% of rainfall converts to useable runoff, the lowest proportion in the world. about 14 million rural and suburban black south africans still do not have access to running water in their homes. rural women have to walk long distances to collect domestic water from rivers or water points. water resource management is crucial for food and ecological security. despite the importance water assumes in overall human development, it is among them most mismanaged resources, especially in the context of developing countries including south africa. neglect of this important resource has resulted in severe food security problems at the household level and environmental degradation of enormous proportions (reddy, 2002). the recent national water policy document lacks substances, direction and seriousness in addressing the real issues pertaining to water. it is a sad reflection of the status of water resources in the country. it narrates only the issues or problem areas, which are widely known and acknowledged. but it is silent on the more important aspects of how to go about tackling the problems. moreover, it does not provide any new insights or approaches (reddy, 2002). role of institutions and policy making on water resource management in south africa resource management practice indicates a great diversity of ways in which individual choices and action are coordinated to balance needs and interests of users with the capacity of the resource system (maarleveld and dangb´egnon, 1999; veeman and politylo, 2002). candice et al. 387 institutional arrangements (government and private sectors) governing the water sector are undergoing remarkable changes and improving the current state of water management in south africa (saleth and dinar, 2000; veeman and politylo, 2002; wostl et al., 2007). strengthening institutions and policy makers for the use and management of natural capital such as water is vital in enhancing economic development and alleviating poverty in south africa (veeman and politylo, 2002; wohlwend, 2007). water legislation in south africa in south africa, water legislation draws on old standing traditions (water tribal), local customs and rules of conduct. water legislation is not an end in itself but it is one of the various instruments (enforcement on water use, policy making, and water regulation) of giving effect to the water policies which it should reflect (saleth and dinar, 2000). accordingly, legislation which is not preceded by, or does not explicitly involve the adoption of certain policies, is unlikely to be effective and non functional (le moigne et al., 1997). the policies may be adopted before the legislation and may even originate with another governmental body. to these two factors, namely, policies and legislation, a third policy should be added which can be: a water development plant for each country, and if necessary, specific planning for some river basins or ground water aquifers should also be included (le moigne et al., 1997). in south africa water legislation have been reviewed based on certain hazards, community conflicts or specific uses through the following stages: 1) legislation oriented towards certain hazards deriving from the existence use of water or water run-off (regulations on flood control, natural run-off of rain-water, and construction of wells. 2) legislation oriented towards particular uses of water (laws on the supply of potable water, irrigation, river navigation, energy, industry, fish breeding) 3) legislation oriented towards multiple uses of water and conservation of water as a resource, such legislation being concerned primarily with water and the coordination of its uses and secondarily with the particular uses themselves; 4) legislation oriented towards the joint management of various natural resources, which takes into account and regulates the interdependence of water and other natural resources (soils, forest, etc) 5) legislation oriented towards the environment and dealing with water and other natural resources. the department of water affairs has a division known as the national water resource strategy and its aim is to: 1) facilitate the proper management of the nation’s water resources; provide a framework for the protection, use, development, conservation, management and control of water resources for the country as a whole 2) provide a framework within which water will be managed at regional or catchment level in defined water management areas and 3) provide information about all aspects of water resource management, 4) identify water-related development opportunities and constraints (dwa, 1998; seward et al., 2006). table 1 indicates water accessibility and usage among radial group, advantage and disadvantage groups. the table shows that blacks are the leading group with high rate of poor individuals (54.8%) and is the most leading group in terms of population (93%). white individuals are the least group affected by poverty with only percentage of 0.4%. indian individuals are the less populated group in south africa with percentage of 2.5%. in figure 1, it can be shown that most of african countries are water stress. looking at south africa specifically, in 1990, water availability per human capita was about between 1000 and 2000 m 3 which shows that already south africa is in water stress situation. according to this figure, it is predicated that in 2025, almost all african countries will be vulnerable in terms of water availability. there are some many factors affecting water availability and these factors are different depending on the countries. population influx, agriculture, developments are the major factors relating to water scarcity. another factor that cannot be predicated and controlled and may negatively affect water availability is climate change. figure 2 indicates the allocation of water use in south africa. in this figure, 52% of water allocation is used for agricultural activities while only 10% is allocated for domestic use. this huge imbalance in terms of water allocation and use indicates that, here are no proper legislations on water resource management in south africa. it seems as if agricultural activities are being considered seriously than human activities. well, this may be due to economic benefit; hence it looks inappropriate as human lives should be the main concern. figure 3 indicates water usage in high income suburbs of south africa. as previously, it looks inappropriate to use more water on gardening and less for human consumption. when looking at the figure 50% of water is used for gardening and only 2% is used for drinking and cooking. this is inappropriate. south africa has serious problems when it comes to policy making on water resource management. there is a lot that need to be done in terms of implementation of new legislation on integrated water resources management. individuals living poor lives wish to have just a cup of clean water while other are using more that of that clean water to decorate their houses. is there any fairness in this? well, 388 afr. j. envir. econ. manage. figure 1. water situations in africa including south africa (fischer and heilig 1997). the answers lie in the hand of policy makers and politics. in figure 4, it can be seen that most of african countries are water stress. south africa is already in water scarcity (less that 1000m3 per capita per year). there are some many factors affecting water availability and these factors are different depending on the countries. in south africa, population influx, agriculture, developments (mining, industries) are the major factors relating to water scarcity. another factor that cannot be predicated and controlled and may negatively affect water availability is climate change. water use among racial groups water scarcity is becoming an increasing problem candice et al. 389 figure 2. water allocation and usage in south africa (jacobson, 2003) figure 3. domestic water usage in high income suburbs of south africa (www.capetown.gov.za). worldwide. over the next few years, an increasing population demand and increasing water use demand will put more pressure on global water resources. by 2025, million of people living in south africa (sa) will live in country with absolute water scarcity (figures 1 and 4). this means that they will not have sufficient water resources to maintain their current level of per capita for domestic purposes. this seems to be a global problem especially in african countries. it has been estimated that a population of nearly 200 million people is facing serious water shortages by the 2025 (figure 4). nearly 230 million africans including south africans will be facing water scarcity, and 460 million will live in water-stressed countries as indicated in figure 1. in south africa there is an imbalance in terms of water allocations and use among different racial groups. table 1 gives an overview on how water is used amongst racial groups, advantaged and disadvantaged people. looking at table 1 blacks are dominant populated group in south africa, having percentage of 80.1% while indians being the least populated (2.5%). in this 80; 54.8% of black individuals are faced with poverty and with no access to potable drinking water. white individuals are the least affected with only 0.4% are affected with poverty and have access to potable water. then, when it comes to percentage share of population and poor individuals; black individuals still lead the groups, having the highest percentage of 93% of poor individuals while white 390 afr. j. envir. econ. manage. figure 4. water stress and scarcity in africa including south africa by 2025 (fischer and heilig 1997). individuals only have 0.1% followed by indian group with percentage of 0.4% (table 1). water allocation and usage in south africa the percentage of water usage for agriculture and irrigation is 52% and only 10% is used for domestic use in south africa (figure 2). additionally, the water usage for gardening is 50% and only 2% is used for drinking and cooking in high income suburbs of south africa and those are the cities where many white individuals live (figure 3). with all these results in terms of water allocation and use in south africa; one could ask: why is there such a huge imbalance in terms of access to natural capitals such as water between racial, advantaged and disadvantaged groups in south africa? the answer lies within the political powers; the poorer you are, the lesser you get and the easier you are forgotten, but the richer and powerful you are the more you get and have access to good living. south africa still has a lot to do in term of implementation of new strategies on water resources management. implementation of new strategies to improve water resources management in south africa water scarcity has become a significant threat to human well-being; a danger of the water scarcity narrative is that, it obscures issues concerning unequal access to and control over water (mehta, 2000). while freshwater candice et al. 391 supplies are clearly limited, for most people water scarcity is caused by competition between water uses and by political, technological and economic barriers that limit their access to water (falkenmark and lundqvist, 1998). the serious inequality in access to and control over water and the conflicts between the different uses and users of water lie at the heart of the need for new approaches to water management. this need is widely recognized as is the belief that existing institutional arrangements for water management are inappropriate and a major constraint for achieving sustainable water management. to make the transition to more sustainable water management, most analysts recommend managing water based on river basins and increasing stakeholder participation in water management (wester et al, 2003). in south africa, poor people are typically deprived of the benefits of water. they are the only people who suffer from life-threatening water-scarcity. poor people are also more vulnerable for the adversities. poverty, defined as a state and process of multi-dimensional deprivation affecting economic, health-related, psychological, sociocultural, legal, and political facets of wellbeing (world bank, 2000/2001) is manifest in society development and management of water resources in at least three ways: first, poor people lack the technological assets to access water. the lack of efficient access to available water resources have lead them to drink water of low quality against excessive labor or cash costs, especially during periods of drought. the same holds true for productive water use, for example for cropping. ineffective water policies and inefficient water infrastructures seriously disrupt societies as well as the environment. for effective and adequately management of natural capitals in south africa, the following policies or legislations need to be revised: 1) legislation oriented towards particular uses of water (laws on the supply of potable water, irrigation, river navigation, energy, industry, and fish breeding). 2) legislation oriented towards multiple uses of water and conservation of water as a resource, such legislation being concerned primarily with water and the coordination of its uses and secondarily with the particular uses themselves; 3) legislation oriented towards the joint management (public, private, stakeholders) of water use and allocation. this is a serious problem in south africa as it has been seen in figures 2 and 3 that agriculture and gardening seem to be the priority with high demand of water use as opposes to human activities. legislation oriented towards the environment and dealing with water and other natural resources; 4) the involvement of communities during policy making can assist in understanding the demands (especially the basics) that the communities require. in addition empowering the communities on conservation management can aid in lessening mismanagement or misuse of natural resources (water). importance of financial management on adequate water resource management politics play major role during the implementation of policy making in south africa. hence, this affects the proper management of water resources due to debates on water allocation to south african individuals. it is the fact that the poor individuals do not benefit much in terms of access to natural resources such as water due to political activities. there is a subsidiary group called water allocation monitoring index in south africa assigned by the department of water affairs. the main role of this group is to ensure that every south african has access to potable water. however, this group seems not in existence, since some if not most south africans “mostly the poorer” still do not have access to potable water. is this group discriminating or could the inefficient operation of this group have to do with politics and money? the interaction between economics and the environment through institutions is important to resource and environmental economics because, in presiding over the establishment of economic institutions, governments or other responsible agencies implicitly direct behavior with respect to resource use (saleth and dinar, 2000; adler, 2005). thus, any discussion of sustainable development and the conservation of natural capital should provide explicit treatment of economic institutions and their role in creating the necessary incentives to achieve these objectives (wolf, 1999; veeman and politylo, 2002). the design and functioning of institutions will therefore determine the manner in which resources are allocated and how the income derived through resource management is distributed. the opportunity and transactions costs of institutional changes are not static but change continuously due to the effects of institutional inter-linkages as well as the impact of changes both in the endogenous (politics, racial groups, economy, population growth) and exogenous factors (impact of climate change on water availability) (wolf, 1999). since the magnitude of net benefits from institutional changes is a direct function of water scarcity, the economic urge for institutional change increases with each increase in water scarcity. thus, as water scarcity becomes acute due to economic development or population growth, the real economic costs of inappropriate water institutions tend to rise (saleth and dinar, 2000). self empowerment of poor individuals on water availability there is a saying that says “the poorer you are, the easily you are forgotten but the richer you are the most important you are in your community” this seems true, in south africa, the most populated individuals are blacks and are the highest in terms of poverty rating. most of this people have no proper housing, proper sanitation, no access to portable water; yes they are still sustaining themselves to live. they do not just sit back and say we are forgotten, they try hard to keep themselves alive, they even voice out to the government to remind them that they are forgotten. on the other hand, some sustain themselves by practicing indigenous knowledge when conditions are harsh for them. however, government and stakeholders in south africa should be willing and in a position to assist poor individuals in improving the quality of their lives by supplying relevant and useful resources or tools that will aid them improve their lives. impact of climate change to water availability: a world problem climate change is a major problem affecting water availability and other natural capitals. this is a global problem and difficult to handle as it’s not predictable. extensive research on the impact of climate change on natural capitals including water is ongoing. with the help of new technologies and satellites that give signals on change in climate, it is promising that climate change can be controlled. but till then, people should be taught on control measures during harsh conditions. hence, the questions are: are those who know on the impact of climate change on natural capitals send important information to those who do not know especially those in rural areas. do richer and poorer individuals work together on control measures during unfavorable conditions (water scarcity), or are poor individuals being discriminated, does the government makes sure that every individual in south africa? conclusion water is the commodity of life, without water many lives are being threatened. there are many challenges regarding water management in south africa. this is mainly due to inadequate rainfall, hence mismanagement of water resources due to political breakdowns and racial groups also contribute to the problem. some of the other challenges may include: limited physical resources, a rapid growing population, and stagnant economies. complex challenges such as these, dictate a critical need to manage and conserve water resources properly. a lot still need to be done in terms of implementation of new strategies to combat some of the challenges negatively affecting proper water resources management in south africa. in addition, legislations on water access and use need to be revised adequately to accommodate every 392 afr. j. envir. econ. manage. south african irrespective of race, poor or richer, educated or illiterate. the water allocation monitoring index in south africa could play a vital role by promoting programs that will ensure all south african get access to domestic and drinking water. however, this group sees not functioning accordingly; this may be due to financial instability and political activities. other institutions such as policy makers, legal boards should also strongly involve themselves during the implementation of strategies on integrated water resource management and adequately revising the existing policies on water usage and allocation in south africa. growth development and population increase are the major factors resulting in ineffective strategies on integrated water resource 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(http://www.bjwconsult.com). wolf at (1999). water and human security. issue no. 3. department of geosciences, oregon state university. world bank world resources institute (2000 – 2001). a guide to world resources: people and ecosystems. wostl cp, craps m, art-dewulf a, mostert e, tabara d, taillieu t (2007). social learning and water resources management. ecol. soc., 12(2): 5. in ternationa l scholars journa ls african journal of environmental economics and management issn 2375-0707 vol. 2 (5), pp. 198-206, may, 2014. available online at www.internationalscholarsjournals.org © international scholars journals author(s) retain the copyright of this article. full length research paper an investigation on the diet composition, seasonal variation in feeding intensity and ontogenetic dietary shifts of l. intermedius in lake koka godana bekere1, kumsa leqa,2 wako ogata2, zenawi asfaw isaias3 1 biology department, addis ababa university, addis ababa, ethiopia. 2 animal and range sciences department, adama science and technology university, adama and asella, ethiopia. 3 department of animal science, faculty of agriculture, admas university college–addis ababa. accepted 21 january, 2014 the food and feeding habits of the african big barb labeobarbus intermedius (rüpell, 1836) was studied based on 390 gut samples collected in aprilmay 2011 (dry months) and julyaugust 2011 (wet months) in lake koka, ethiopia. frequency of occurrence and volumetric methods of analysis were used in this study. macrophytes, detritus and insects were the most important food items occurring in 79.1%, 80.0% and 62.5% of the guts, and accounting for 46.3%, 27.5% and 18.2% of the total volume of food, respectively. the contributions of phytoplankton, zooplankton, fish scales and ostracods were relatively low. macrophytes and detritus were important food items during the wet months occurring in 96.2% and 60.9% of the guts, respectively and comprising 66.1% and 24.0% of the total volume of food items, respectively. the contribution of insects was low during the wet months. detritus, macrophytes and insects were found to be the dominant food items in all size classes, whereas the contributions of ostracods, fish scales, zooplankton and phytoplankton were low. based on the results it can be concluded that l. intermedius was omnivorous in its feeding habits in lake koka. keywords: l. intermedius, feeding habits, lake koka, ontogenetic diet shift. introduction the african big barb labeobarbus intermedius (rüppell, 1836) is widely distributed in northern kenya and in most parts of ethiopia. it is one of the commercially important fish species in ethiopian fisheries (lfdp, 1997; bjørkli, 2004; desta et al., 2006). according to lfdp (1997), the annual yield of l. intermedius was about 365 tons per year from the inland water bodies of ethiopia. however, recently the consumption of l. intermedius in some rift valley lakes (lakes hawassa and koka) declined because it was found to be not safe for human consumption due to high mercury concentration (mengesha, 2009). *corresponding authors: e-mail: godanabekere@yahoo.com. the diet composition of fish may vary with in wide ranges on temporal and spatial conditions and environmental factors (cabana et al., 1994). according to persson and crowder (1998), the major factors that influence fish diet are fish size, maturity, condition, season (water level), bottom, depth, latitude, longitude and habitat types. in aquatic systems where the water levels in lakes and reservoirs have been known to fluctuate, the quality and abundance of food items for fish vary significantly through time (cabana et al., 1994). a particular characteristic of fish is that individuals increase in size during their ontogeny and this increment in size is correlated with changes in food quality and quantity in aquatic systems and growth varies according to food availability in the environment (werner, 1988). various authors have studied the food and feeding habits godana et al. 198 of l. intermedius in ethiopia (admassu and dadebo, 1997; sibbing, 1998; de graaf, 2003; assaminew, 2005; desta et al., 2006; mengesha, 2009; deribe et al., 2011). admassu and dadebo (1997) studied the diet composition, length-weight relationship and condition factor of l. intermedius in lake hawassa and reported the diet composition of the species to be phytoplankton, insects, detritus, macrophytes, gastropods and fish. desta et al. (2006) have also studied the feeding habits of l. intermedius in lake hawassa in connection with its mercury concentration and have reported the food items of the species as gastropods, aquatic insects, macrophytes, detritus, fish fry and fish eggs. sibbing (1998) reported that the diet of l. intermedius in lake tana was composed of benthic invertebrates, mainly insect larvae and detritus. according to assaminew (2005), the diet of l. intermedius was composed of macrophytes, detritus, insects, nematodes, fish, fish eggs and fish scales in lake koka. information on the biology and ecology of l. intermedius from lake koka is scanty. assaminew (2005), mengesha (2009) and deribe et al. (2011) have studied the diet of l. intermedius in lake koka and reported the omnivorous feeding habits of the species. the type of food items consumed by l. intermedius depends on prey availability, season and habitat differences and size of the fish (admassu and dadebo, 1997; sibbing and nagelkerke, 2001; desta et al., 2006). the available information on the biology and ecology of this species from lake koka is not sufficient to guide the management of the lake. such area specific information is vital for proper management and utilization of the stock. the purpose of this study was therefore, to investigate the diet composition, seasonal variation in feeding intensity and ontogenetic dietary shifts of l. intermedius in lake koka. materials and methods the study area lake koka (latitude: 8 ° 19 ’ 8 ° 28 ’ n and longitude: 39 ° 01’ 39 ° 09’ e) is located in the northern part of the main ethiopian rift (mer) valley, in the awash basin about 100 km south east of the capital city, addis ababa. it is located at 1,590 m and has an area of 180 km 2 (figure 1). the region is characterized by a semi-arid to subhumid climate (peder, 2009). the main rainy season starts in june and extends to the end of august/september, while the short rainy season occurs from march to may. the phytoplankton biomass was measured to be 5.9 mm 3 l -1 and dominated by microcystis (mesfin, 1988). the zooplankton was low in diversity but abundant, and there were large populations of benthic invertebrates (peder, 2009). the mean annual maximum and minimum temperatures are 30.4 ° c and 14 ° c, respectively as well as the mean depth of 9 m (kibret, 2010). the dam is the first hydropower plant in ethiopia by generating electricity for addis ababa and other urban centers. in addition to electricity generation recently the dam is also used for downstream irrigation that is accounted for 6,000 ha wonji sugarcane project. the area is characterized by a wide and open plain suitable for cultivation of agricultural crops. vegetables are grown around the reservoir in the wetland created by the receding reservoir water and using diesel water pumps to extract the shallow ground water. sparsely distributed acacia trees are common in the area (kibret, 2010). main habitats are the surrounding farmland and partly protected woodland beside the dam site and hot springs below it. eichhornia crassies has invaded the lake and spreading very rapidly (mesfin, 1988). the main activity in the area is farming and the widely grown crop is eragrostis teff. the farmers using the alluvial soil around the lake also grow horticultural crops and pulses particularly haricot beans (mesfin, 1988). the fishery of lake koka is dominated by four fish species. these are the nile tilapia (oreochromis niloticus), the common carp (cyprinus carpio), the african catfish (clarias gariepinus), and l. intermedius. a tiny cyprinodont minnow (aplocheilichthyes antinorii) also exists in the lake. according to the ethiopian department of fisheries and aquaculture, the lake supports a fishing industry of 625 tons of fish each year. the dominant species is o. niloticus that contributes about 327 tons per year (59% of the total landings) (lfdp, 1997). the lake attracts people for work and new settlement to develop extensive farming in the catchment. the floriculture farms around the lake release their untreated effluents directly to the lake (mesfin, 1988). these effluents contain fertilizers and pesticides may cause pollution and contribute to eutrophication. recently the lake has suffered from severe green algae bloom and was referred to as “the green lake” (peder, 2009). the greatest threat to lake koka itself is sedimentation and recent studies show the rate of sedimentation 25 million m 3 annually. fish sample collection and measurements fish samples of adult l. intermedius were purchased from the local fish market. fishermen in lake koka use gillnets of 100-160 mm stretched mesh size. then they set their nets late in the afternoon and collect the catch early in the morning the following day. in addition to the 199 afr. j. environ. econ. manage. figure 1: map of ethiopia with the relative position of lake koka indicated (a) and map of lake koka with the sampling area indicated adult fish, fingerlings were sampled in the shallow littoral area using a beach seine of 6 mm mesh size. fish samples were collected twice during the dry season (april and may) and twice during the rainy season (july and august). after collection total length (tl) was measured to the nearest millimeter and total weight (tw) was weighed to the nearest 0.1gram. gut content analysis we preserved the contents of all non-empty guts in 5% formalin solution for further analysis in the laboratory. since l. intermedius is a stomachless fish we sampled the content up to the first bend of the intestine. visual examination was used to identify larger food items, but a dissecting microscope (leica ms5) and a compound microscope (leica dme) were used to identify microscopic food items. in order to investigate the relative importance of the different food items, we used the following methods of analysis. frequency of occurrence the number of examined guts in which one or more of a given category of food items was found was expressed as a percentage of the total number of non-empty guts (windel and bowen, 1978). this method gives information on the proportion of a particular population of fish that fed on that particular food item. volumetric analysis the food items that were found in the guts were categorized into different taxonomic groups and the volume of each group was measured (bowen, 1983). then the volume of a given category of food items was expressed as a percentage of all the categories of food items present in the samples. the importance of different food items for different size classes was determined by dividing the fish into four size classes (i< 20.0 cm tl, ii20.0-29.9 cm tl, iii30.0-39.9 cm tl and iv> 40.0 cm tl) and determining percentage mean volume of food in each size class. results diet composition out of the total number of 266 adult fish samples collected 250 (94.0%) were non-empty while the remaining 16 (6.0%) were completely empty. the length and weight range of the adult fish was 23.3 cm tl to 49.0 cm tl and 95.4 g to 1,200 g tw. in addition to the adult fish, 70 fingerlings collected from the shallow littoral area of the lake were included in the gut content analysis. the size range of the fingerlings was 5.9 cm to 11.4 cm tl godana et al. 200 figure 2: the relative proportions (%) of different food items in the diet of l. intermedius using frequency of occurrence and volumetric analysis methods from lake koka (macmacrophytes, det-detritus, ins-insects, phy-phytoplankton, ost-ostracods, sca-fish scales and zpk-zooplankton). table1: frequency of occurrence and volumetric contribution of different food items in the diet of 320 l. intermedius from lake koka. food items frequency percent volume(ml) percent phytoplankton 69 21.6 22.9 2.1 blue green algae 40 12.5 5.0 0.5 green algae 51 15.9 10.0 0.9 diatoms 62 19.3 8.0 0.7 zooplankton 31 9.7 25.4 2.3 rotifers 8 2.5 0.1 0.01 copepods 9 2.7 1.2 0.1 cladocerans 1 0.3 24.1 2.2 insects 200 62.5 198.5 18.2 diptera 155 46.1 135.2 12.4 ephemeroptera 36 11.3 12.3 1.1 coleoptera 49 14.6 32.6 3.0 hemiptera 31 19.2 14.6 1.3 plecoptera 14 4.4 3.7 0.4 detritus 256 80.0 300.3 27.5 macrophytes 253 79.1 506.8 46.3 fish scale 48 15.0 21.8 2.0 ostracods 61 19.1 17.9 1.6 and 1.6 g to 12.4 g tw. all the fingerlings were nonempty. the food items identified from the gut contents of l. intermedius were macrophytes, detritus, insects, phytoplankton, zooplankton, ostracods and fish scales (figure 2, table 1). from these food items macrophytes, detritus and insects occurred in high number of guts and constituted the bulk (92.0%) of the food consumed by volume (figure 2, table 1). the remaining food items accounted for only 8.0% of the total volume of food items. 201 afr. j. environ. econ. manage. figure 3: the relative proportion (%) of different food items in the diet of l. intermedius during dry month (a) and wet month (b) from lake koka (det-detritus, mac-macrophytes, ins-insects, phyphytoplankton, ost-ostracods, sca-fish scales and zpkzooplankton). macrophytes were the most important food items occurring in 79.1% of the guts and constituting 46.3% of the total volume of food items (figure 2, table 1). detritus occurred in 80.0% of the guts and accounted for diptera were by far the most important groups occurring in 46.1% of the guts and constituting 12.4% of the total volume (table 1). the contribution of other groups of insects was low (table 1). the frequency of occurrence of phytoplankton was relatively high (21.6%) but their total volumetric contribution was rather low (2.1%). blue green algae, green algae and diatoms were encountered during the present study, among which green algae had the highest contribution (table 1). zooplankton occurred in 9.7% of the guts and accounted for 2.3% of the total volume of food consumed (figure 2, table 1). fish scales occurred in 15.0% of the guts and accounted for 2.0% of the total 27.5% of the total volume of food items (figure 2, table 1). insects occurred in 62.5% of the guts and their volumetric contribution was 18.2% of the total volume of food items (figure 2, table 1). among the insect groups, volume (figure 2, table 1). ostracods occurred in 19.1% of the guts and constituted 1.6% of the total volume (figure 2, table 1). seasonal variation in the diet of l. intermedius there was notable variation in the type of diet and the proportions consumed by l. intermedius in lake koka during the dry and wet months. generally, the number of food items consumed during the dry month was much higher (seven) than the number of food items consumed during the wet month (three) (figure 3a, b). godana et al. 202 table 2: frequency of occurrence and volumetric contribution of different food items in the diet of 320 l. intermedius during dry and wet months from lake koka. frequency occurrence (%) volumetric contribution (%) food items dry months wet months dry months wet months phytoplankton 42.1 5.7 blue green algae 24.4 1.2 green algae 31.1 2.5 diatom 37.8 2.0 zooplankton 17.1 6.1 rotifers 2.4 0.02 copepods 5.5 0.3 cladocerans 15.4 5.8 ostracods 37.2 4.4 insects 81.7 41.0 32.5 9.8 diptera 76.2 19.2 25.4 4.7 hemiptera 18.9 3.6 ephemeroptera 20.7 1.3 2.5 0.4 coleoptera 0.6 30.8 0.2 4.7 plecoptera 7.9 0.6 0.7 0.1 detritus 98.8 60.9 34.0 24.0 macrophytes 62.8 96.2 12.7 66.1 fish scales 24.4 4.6 detritus was the most important food item during the dry month. it occurred in 98.8% of the stomachs and volumetrically its contribution was 34.0% of the total volume of food items (figure 3a, table 2). insects occurred in 81.7% of the stomachs and accounted for 32.5% of the total volume food consumed (figure 3a, table 2). diptera were the most important food items among the insect groups. they occurred in 76.2% of the stomachs and constituted 25.4% of the total volume of food items (figure 3a, table 2). the contribution of other groups of insects was low because of their low frequency and volumetric contributions (figure 3a, table 2). macrophytes and phytoplankton occurred in 62.8% and 42.1% of the stomachs, respectively and comprised 12.7% and 5.8% of the total volume food items, respectively. ostracods, fish scales and zooplankton occurred in 37.2%, 24.4% and 17.1% of the stomachs, respectively. their volumetric contributions were 4.4%, 4.6% and 6.1% of the total volume of food items, respectively (figure 3a, table 2). during the wet month, macrophytes were the most important food items occurring in 96.2% of the guts and accounting for 66.1% of the total volume food items (figure 3b, table 2). detritus occurred in 60.9% of the guts and comprised 24.0% of the total volume food consumed (figure 3b, table 2). the contribution of insects was relatively low. they occurred in 41.0% of the guts and constituted 9.8% of the total volume of food items (figure 3b, table 2). during the wet month the contributions of foods of plant origin was very high while the contributions of animal prey was low. ontogenetic dietary shift percent mean volume contribution of different food items with size of fish is given in (figure 4). detritus, macrophytes and insects were the dominant food items in all size classes, whereas the contribution of ostracods, fish scales, zooplankton and phytoplankton was low (figure 4). in size class < 20.0 cm tl the dominant food items were detritus 39.7% followed by insects 36.3% (figure 4). the contributions of macrophytes and zooplankton were 10.0% and 6.1%, respectively of the total volume of food items. the contributions of ostracods, fish scales and phytoplankton were 3.3%, 1.4% and 3.1% of the total volume of food items, respectively (figure 4). in this size class, the most important food items were detritus and insects. these two food items constituted 76.0% of the total volume of food consumed (figure 4). the remaining food items constituted 24% of the total volume of food items (figure 4). in size class 20.0-29.9 cm tl macrophytes, detritus and insects were important food items accounting for 45.0%, 34.7% and 12.8% of the total volume of food items, respectively (figure 4). these three food items constituted 92.5% of the total volume of food items within that size class (figure 4). the less important food items namely, ostracods 0.9%, fish scales 2.8%, zooplankton 1.0%, and phytoplankton 2.8% collectively constituted less than 10% of the volume of food consumed within the size class (figure 4). the dominant food items in size class 30.0-39.9 cm tl figure 4: the relative proportion (%) of different prey items in the diet of l. intermedius at different size classes from lake koka (det-detritus, mac-macrophytes, ins-insects, ost, ostracods, sca-fish scales, zpk-zooplankton and phy-phytoplankton). were macrophytes 48.6%, detritus 25.8%, and insects 19.6% and these three food items constituted 94% of the total volume of food items within the size class. the contributions of ostracods 1.5%, fish scales 1.4%, zooplankton 0.8% and phytoplankton 2.2% were relatively low, collectively constituted only 6% of the total volume of food consumed in that size class (figure 4). in size class >40 cm tl the order of the importance of dominant food items was similar. macrophytes, detritus and insects constituted the bulk of the food items consumed. these food items accounted for 45.0%, 33.0% and 12%, respectively of the total volume of food items consumed within the size class (figure 4). the less important food items were again ostracods 2.7%, fish scales 4.0%, zooplankton 0.3% and phytoplankton 2.9%. the dominant food items constituted about 90% of the total volume of food items while the minor food items constituted only about 10% of the total volume of food items within the size class (figure 4). discussion l. intermedius fed mainly on detritus, macrophytes and insects in lake koka. unlike the present study, the major food items of l. intermedius were mollusks, fish prey and aquatic insects in lake hawassa (desta et al., 2006). comparable with the present study the main food items of l. intermedius constituted macrophytes, detritus and aquatic insects in lake koka (assaminew, 2005). similarily, in lake tana the diet of l. intermedius was dominated by benthic prey organisms especially insect larvae and detritus (sibbing, 1998; de graaf, 2003). diet studies of big barbs from other inland waters of africa and asia have been shown to be omnivorous and the fish is able to change its diet depending on availability of prey, seasonal and spatial differences (admasu and dadebo, 1997; sibbing and nagelkerke, 2001). the high occurrence and volumetric contribution of detritus in guts of l. intermedius showed the significant contribution of this food item in their nutrition. detritus is reported as a dominant food item of b. bocagei, b. staeindachneri and b. cyclolepis and additional food for b. comiza in maritza river from bulgaria (losos et al., 1980). dietary studies on big barbs in different lakes showed that (corbet, 1961; cambray, 1983; admassu and dadebo, 1997) the ingestion of detritus, sand particles and benthic food items indicated the ability of the species to possess benthic habitats. detritus is considered low in nutritional value (bagenal and braum, 1978; bowen, 1979). several studies in lotic and lentic water systems have considered that an increased 203 afr. j. environ. econ. manage. godana et al. 204 consumption of detritus is a prime response to a decline of higher value primary food resources (bowen, 1979; king et al., 2003). the importance of insects mainly dipterans in the diet of different barbus species was reported by various authors (hyslop, 1980; losos et al., 1980; piet, 1998). this was probably due to the dense stand of aquatic weeds that support significant biofilm assemblage of benthic prey production noted by piet (1998). nagelkerke and sibbing (1993) reported the importance of macrophytes in the diets of b. sukris and b. truttiformis in lake tana, ethiopia. the results of the present study are in agreement with the findings of other investigators in different water bodies of africa where macrophytes, detritus and insects dominate the gut content of the species. unlike the present study, desta (2006) reported the dominance of gastropods in the diet of b. intermedius in lake hawassa the volumetric contributions of zooplankton, phytoplankton, ostracods and fish scales were relatively low in the diet of l. intermedius. these food items could probably be consumed accidentally when the fish searches other food items in the environment. according to losos et al. (1980) mollusks, beetles larvae and ants were incidentally consumed in the diet of b. cyclolepis because of their low volumetric contributions in maritza river, bulgaria. in many tropical freshwater ecosystems zooplanktivorous fishes were poorly distributed (piet, 1998). de graaf (2003) documented three zooplanktivorous barbs, two small barbs (b. tanapelagius and b. humalis) and one big barb b. brevicephalus in lake tana. zoopanktivory and the filter feeding habits on zooplankton are rare in tropical waters (de graaf, 2003). piscivory was not observed in the diet of l. intermedius during the present study. this is probably due to the presence of a top predator, c. gariepinus which feeds on c. carpio, o. niloticus, barbus sp. piscivory is not common in cyprinids due to the absence of oral teeth and the shortage of stomach acidity (sibbing, 1982; desta et al., 2006). however, piscivory is relatively common among the african cyprinids due to the presence of sufficient fish prey and the absence of other piscivorous fishes while in europe some cyprinids specialized on fish even in the presence other piscivorous fish (desta et al., 2006). nagelkerke (1997) noted that in lake tana, ethiopia five out of eight big barbs found to be specialized on fish and the nature of piscivory is due to the abundance of b. humilis in the littoral region and b. tanapelagius in the pelagic area. high level of piscivory was observed in the diet of b. intermedius in lake hawassa, ethiopia (admassu and dadebo, 1997; desta et al., 2006). seasonal variation was observed on the type of food and their proportion during the dry and wet periods of the year detritus and insects were the most important food items during the dry period. detritus was probably ingested with insects when the fish was trying to pick insects from the sediment assisted by their ventral mouth projection that is suited for benthic feeding (adeyemi, 2009). during the wet period of the year, macrophytes and detritus were the most important food items. the source of detritus could be probably floods that introduced fragments of plant materials in the lake. balcombe et al. (2004) suggested that barbus sp. consumed more detritus and fewer insects during high water level in a sri lankan reservoir. high water levels designated as resource rich while low water levels have poor resources in trophic dynamics in lentic systems (balcombe et al., 2004). the availability of food items changes throughout the year in tropical region due to seasonal changes and feeding habits of fish depend on seasonal variation (desta et al., 2006; peder, 2009). fingerlings mostly fed on detritus and insects in large amounts while in larger size classes macrophytes, detritus and insects were the most dominant food items. the remaining food items were of minor contribution in the diet of l. intermedius. an attempt was made to determine ontogenetic diet shift. there was slight ontogenetic variation in the diet of l. intermedius among the different size classes. the importance of macrophytes, detritus and insects was dominant in all size classes while the contributions of ostracods, phytoplankton, zooplankton and fish scales were low regardless of their size. the slight variation observed was that macrophytes were relatively unimportant in the diet of the smallest size class while they are dominant food items in larger size classes. moreover, insects that were dominant in the smallest size class were relatively unimportant in larger size classes. desta et al. (2006) studied the feeding habits of l. intermedius in lake hawassa and reported slight ontogenetic diet shift in l. intermedius from lake hawassa. they noted that insects were important food source for juvenile, but their importance declined with size of fish. the results of the present study agree well with the report of desta et al. (2006). desta et al. (2006) also reported that l. intermedius in lake hawassa shifted to piscivorous feeding habits as its size increases. however no fish prey was encountered in the present study. corbet (1961) studying b. altianalis in lake victoria and spataru and gophen (1987) working on b. altianalis in lake kinneret, (israel) pointed out lack of ontogenetic diet shift and therefore, small and large sized fish consumed similar food items. conclusion the most important food items of l. intermedius in lake koka were detritus, macrophytes and insects while 205 afr. j. environ. econ. manage. zooplankton, fish scales, phytoplankton and ostracods were low in their contribution. during the dry period the food items that were identified in the diet of l. intermedius were detritus, insects, macrophytes, zooplankton, fish scales, phytoplankton and ostracods. among these food items detritus, insects and macrophytes were the most important food items while the remaining food items were low in their contribution. during the wet period only three food items were identified. these were macrophytes, detritus and insects and all were important in the diet of l. intermedius. the dominant food items in all size classes were detritus, macrophytes and insects while the remaining food items were low in their contribution. detritus and insects were the dominant food items of juveniles, while macrophytes, detritus and insects were the dominant food sources of adults. generally, l. intermedius was found to be omnivorous in its feeding habits; macrophytes become more important in its diet as it grows older. acknowledgements we thank fishermen kecha fiche and abu geleta for their assistance during the fieldwork. yirgashewa bekele is acknowledged for assisting us during the laboratory work. thanks are also due to dr. andargachew gedebo, the norad project coordinator, for providing a vehicle for the field trips. biology department of hawassa university provided us the necessary facilities and laboratory space. ethiopian ministry of education provided financial assistance for the second author. references adeyemi so (2009). food and feeding habits of some commercially important fish species in gbedikere lake, bassa, kogi state, nigeria. int. j. lak. riv. 2(1): 31-36. admassu d, dadebo e (1997). diet composition, length-weight relationship and condition factor of barbus species (rüppell, 1836) (pisces: cyprinidae) in lake awassa, ethiopia. sinet: ethiop j. sci. 20: 13-30. assaminew k. 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feeding habits of barbus longiceps (cyprinidae) in lake kinneret (israel). hydrobiol., 110: 331-337. werner ee (1988). size, scaling and evolution of life cycles. pages 6081. in b. ebenman and l. persson, 2 nd eds. size structured populations: ecology and evolution. heidelberg, springer-verlag. windel jt and bowen sh (1978). methods for a study of fish diets based on analysis of stomach contents. pages 219226. in methods for the assessment of fish production in freshwaters, ibp handbook no. 3. black well scientific publications, london. 10 in ternationa l scholars journa ls african journal of environmental economics and management issn 2375-0707 vol. 6 (1), pp. 394-405, january, 2018. available online at www.internationalscholarsjournals.org © international scholars journals author(s) retain the copyright of this article. review an evaluation of the development trends of research on natural resource management in nepal mahamoudou traoré yonli geography, research division, tu, kirtipur, tribhuvan university, nepal. e-mail: mahamoudouyonli@gmail.com accepted 21 november, 2017 this paper discusses the development trends of participatory research in nepal with reference to natural resource management, taking example from karnali watershed area. the issues discussed in this paper clearly indicate that there is urgent need to promote the participatory action research on environment and development for the proper links between population, development, technological implication and institutional strengths, using a micro level conservation and development model that suits local environments. the author opines that both government organizations and academic institutions have to join hands with an effort to promote the participatory research culture in karnali watershed area for sustainable natural resource management. key words: scientific research, relaxed rapport, extractive survey, eco-development, integrated conservation and development planning, village level model. introduction over the decades, there have been drastic changes in modes of research and learning. shifts from logicalpositivism paradigms (quantitative) to phenomenological paradigms (qualitative) have been witnessed in research and development practices since 1980s. these shifts move now from top-down to bottom-up and from extractive survey questionnaires to participatory appraisal, in which more and more activities for innovation, management and development of available resources are done by local people rather than outsiders. it is seen that various methods and approaches of participatory research evolved from here, with local people learning these methods themselves in order to map out their conditions in planning and action. an important method of participatory research is rapid rural appraisal (rra), which had a widespread in the 1980s. its further evolution, which was met in the 1990s, into participatory rural appraisal (pra) has grew fast and promoted participatory action research (par), participatory learning action, focus group discussion and perception study for development dialogue with a view to enable local people share, enhance and analyze their knowledge of life and conditions to plan and to act. thus, the participatory research in natural resource management and development appeared since 1990s with several sources, reasons and traditions; however, the term activist participatory research was introduced in the 1970s by the work and inspiration of paulo freire in his book pedagogy of the oppressed (rhoades, 1990; chambers, 1995). historically, it evolves continuously quicker and closer communication, transfers and sharing of activist participatory research, agroecosystem analysis, applied anthropology, field research and rapid rural appraisal. particularly, field research on farming systems and conservation of natural and environmental resources by geographers, agricultural economics or biological scientists have contributed in shaping the present form of the participatory research in a complex structure. location of the karnali watershed area the karnaliwatershed basin (kwb) lies in the western part of the mid western development region of nepal, which is about 500 km west from the capital city, katmandu, of the country. it is located between 27°42' n mahamoudou 395 figure 1. map of karnali watershed area. to 30°27' north latitude and 81°e to 83°45' east longitude, extending from dhaulagiri himal in the east to bayas-rishi himal in the west. the total spatial cover of the area is 42,559 sq km, which is about 29.02% of the country. its average length is 176.59 km from the east to west with non-uniform width of 240 km from the north to south (mofsc, 2010). hence, the north-south extension of the basin makes great variations between ecological regions namely: mountain, hill and tarai in regard to relief features, climatic characteristics, and distribution pattern of resources. however, about 80% of the land is covered by rugged terrain. the elevation ranges from 129 m in the southern plain area to 7,000 m height in the northern mountain (cbs, 2007). it borders the western development region in the east, far-western development region in the west, uttar pradesh of india in the south, and the tibetan region of china in the north (figure 1). review of participatory research activities researchers and scientists believe that participatory research is a legitimate and useful method of scientific research in natural and social sciences by rapid assessment procedures like conversation, observation, informal interviews and focus group discussion of realities. chamber (1989) pointed out many reasons to the origin of the rapid rural appraisal that further evolved into participatory rural appraisal and participatory action research. among them, the first reason was dissatisfaction with anti-poverty biases of rural development by urban-based professionals. these biases were spatial (visit to nearby cities, on roadsides, and to the villages’ centers with neglected peripheries), a project that gave special attention to the donor desires rather than people’s demands, a person meeting men more than women, and elites more than the poor and disadvantaged groups, seasonal visits to sites in favorable weather, and diplomacy, that is, where the outsiders do not wish to cause offence by asking to meet poor people in bad conditions. the next one is disillusionment with the normal processes of the questionnaire survey and their results. this is as a result of the fact that the conventional approach to research tended to be long drawn-out, tedious, difficult to administer, a nightmare to process and write up, inaccurate and unreliable data obtained, and difficult to use in wider perspectives. another important preseason was more positive and was in favor of this study to make it a more cost-effective method of learning. it was developed by the growing recognition of the development professional to discern the fact that rural people are knowledgeable on many issues which touched their lives and which are recognized as the indigenous technical knowledge (itk) to tap it more effectively, as a source of information for analysis and use by outsiders. in the mid of the 1990s, it became a more popular model of research and development in asia, africa and south america in both the gos and ngos sectors. it also became the main theme of field research for academic institutions and it spread internationally. many international ngos contributed to shape its present form, which is important for need based development activities. among them, international institute for environment and development (iied) london, institute of development studies (ids) uk, world bank, action aid and win rock international have played significant role to promote the participatory research. therefore, it is a simple method, with set of approaches for scientific inquiry that enable local people conduct their own analysis and often plan and take action. principles of participatory research to carry out a good and practicable participatory research, some important performances are required by the practitioners, and they are briefly discussed here. a reversal of learning: to learn from rural people directly, on site and face-to-face, thereby gaining from local physical, technical and social knowledge. learning rapidly and progressively: with conscious exploration, the flexible use of the methods of opportunism, improvisation, iteration and cross checking do not follow a blueprint program, but the ability to adapt in any learning process. offsetting biases: rural development is all about relaxing and not rushing, listening and not lecturing, probing instead of passing on to the next issues, being unimposing instead of important, and seeking out the deprived people and learning their concerns and priorities. optimizing trade-off: relating the cost of learning to the useful truth of information, with trade-off between quantity, relevance, accuracy and timeliness. this includes the principles of optimal ignorance knowing what is not worth knowing, and of appropriate imprecision not measuring more than needed. as keynes is reputed to have said; it is better to be approximately right than to be precisely wrong. triangulating: using a range of methods, types of information, investigators and disciplines to cross-check. 396 afr. j. environ. econ. manage. seeking diversity: this has been expressed in terms of seeking variability rather than average and has been described as the principle of maximum diversity or maximizing the diversity and richness of information. this can involve sampling in a non-statistical sense. it goes beyond the cross checking of triangulation. defined broadly, it deliberately looks for notices and investigates contradictions, anomalies and differences. facilitating: rural people are allowed to facilitate investigation, analysis, presentation and learning by themselves, so that they present and own the outcomes, and as well learn from it. this has been expressed as ‘handing over the stick’. this often entails an outsider starting a process and then sitting back or walking away, and not interviewing or interrupting. self-critical awareness and responsibility: facilitators continuously examine their behavior, and try to do better. this includes embracing error-welcoming error as an opportunity to learn to do better and using one’s own best judgment at all times, that is, accepting personal responsibility rather than vesting it in a manual or a rigid set of rules. all these principles are behavioral, since they are applied in practice by people doing things. thus, the quality and accuracy of participatory research in environment and development area depend on the moral responsibility and technical efficiency of researchers. in the new millennium, it is more applicable in integrated conservation and development planning with respect to climate change adaptation and humanitarian issues. thus, it requires picking up an appropriate theme and area of research that has in the priority of the country issues that suite the interdisciplinary research. however, funding institutions do not provide grants to such research in general due to the tradition of providing grant based on donor desires rather than local needs and demands. it further demands that the old concept of research and fund granting traditions should be modified to make it more applicable for use in research outputs into socio-economic development with due consideration of natural resources conservation and development policies of the country, which could be carried out with indepth investigation, critical inquiry and exact assessment in seeking facts through collective efforts. conducting such research in an environment with natural resource appraisal and development, self searching methods of inquiry that promote the culture of self-research with participatory mapping and modeling of what is on ground are used. it also requires that trend analysis, livelihood analysis, analysis of difference and participatory planning and budgeting should be done. innovation of participatory research participatory research has broken new ground of research mahamoudou 397 and methods of rediscoveries that encourage people to improvise the spirit of play. various discoveries and innovations of participatory research have existed since the last three decades, and are briefly reviewed. villagers’ knowledge and capabilities: the first discovery is that villagers have a greater capacity to map, model, estimate, rank and score their surrounding resources than outsiders. findings of the participatory research show that rural people have more extensive and detailed mental maps than urban people and that when given the right conditions and materials, they can express this visibly on ground or on paper as three dimensional models (that is, watersheds). rural people have now noticed social details using local materials such as seeds, manure, vegetables; land resource, water resource, market and other information. it evinces that having the right methods and materials, villagers can show themselves capable of generating and analyzing information far beyond normal professional expectations. it is evident that rural people are able to use largely independent culture of literacy to reflect and rank the problems and opportunities as they perceive them, and express their preferences for improving their farming system, managing and using common property resources for better livelihoods and for development actions in their communities. relaxed rapport: the second discovery (the relaxed rapport between outsiders and rural people) can be established early in the process, which is the key to facilitating participation. to measure trust and minimize predisposing conditions for inquiry, it promotes the culture of honest and accurate sharing of detailed knowledge and values between outsiders and villagers. diagramming and visual sharing: the discovery is the power of diagramming and visual sharing information. it helps to transfer the world of the person interviewed into paper and to change the information into public goods from personal to unverified. with visual sharing of map, the model, diagram or unit can be used for ranking, scoring, counting, or quantification, and all who are present can see, point, discuss, manipulate and alter physical objects or representation. triangulation takes place with people crosschecking and correcting each other. learning becomes more progressive and information is visible by the public, checked, verified, amended, added to and owned by the participants. through participatory mapping and modeling, villagers can draw and model their resources with location, deciding what to include, debate, add and modify in the details. in shared diagramming information, seasonal changes dimensions, such as rainfall, agricultural production, labor, income, indebtedness, food security and migration trends can be shown in paper or other local materials. in the media, villagers commend and alter the fact of whether they are literate or not with confidence. sequences: the next popular discovery is the sequences of participatory methods like participatory mapping, social mapping and matrix scoring or ranking, which have more striking combinations and sequences that present new and complementary information on socio-cultural, natural resources and livelihood improvement aspects. in many areas, participatory resource map leads to transect planning, in which villagers made the map act as guides for outsiders. it further leads to the identification and discussion of problems and opportunities and then leads to listing and ranking options. a village social map provides up-to-date household information which leads to discussion, negotiation and reconciliation of priorities. thus, the power of such sequences is four fold. first, the commitment of participation increases, before it further makes the action more likely, spontaneous and sustainable. secondly, sequences triangulate and reveal errors of omissions in earlier presentations. thirdly, the different activities interact cumulatively, and each activity add a dimension to the quality of details and enrich others, so that when taken together the whole become more than the sum of the parts. fourthly, all concerned learn through the process, through people sharing what they know, through observation and through analysis. therefore, participatory methods fit well with flexible learning process approach which is even more openended and adaptable to the villagers. thus, it enables them use their own categories and criteria to generate their own agenda, and to assess and indicate their own priorities. training and reorientation for outsiders: the fifth innovation of participatory mapping, which is the initial training and orientation given to outsiders, can be conducted in practice in a short span of time. face-toface field experience is the main thrust of participatory research. hence, the principles of optimal unpreparedness are applied. usually, it is best to start sooner; as such, it seems safe or sensible for newcomers not to wait, but to start, stumble, self-correct and then share. through participatory methods, villagers are encouraged to map, participate and plan for the training of outsiders to facilitate changes in perceptions and action, listening and not lecturing, learning progressively, embracing error and being critically self-aware of participation. thus, the reversing role is taught to villagers in order for them to perform village tasks. for some outsiders, especially those who have had a strictly formal professional training, this can threaten trauma. they deserve sympathetic understanding, and no significant change may take place. for some though, a new range of possibilities and sense of freedom to experiment and innovation opens up. thus, there is no need for the villagers to be trained in all methods. the methods can be tried, improvised and adopted subsequently, and new ones can be invented. sharing and spread: the last and most important discovery is sharing the culture and spread of technologies through participatory research. participatory research is recognized now to have three foundations: methods, behavior and attitudes, and sharing. previously, methods appeared to be the most important than behavior and attitudes of the outsiders, but now sharing is the most important for spreading of experience and mutual learning. to share and exchange methods and experience, interchanges of staff are efficient; as such, staff of one organization spending time with staff of other organizations can enhance the creativity and inventiveness of villagers to come into play. in such ways, innovations can be continuously stimulated. thus, all forms of sharing-trainings, trainers, ideas, experiences, methods and innovations take place. practical application of participatory research participatory research methods, approaches and techniques have been widely used for appraisal, analysis and research in many subject areas such as agro ecosystems, natural resources, environment, technology and innovation, health and nutrition, family system research and extension, pastoralism marketing, disaster risk reduction, organizational assessment, socio-cultural and economic conditions. participatory appraisal and planning, participatory implementation, monitoring and evaluation, and training and orientation for outsiders and villagers are the major processes that have been used in development and resource management areas. however, most of the application of the participatory research can be listed out in four categories. natural resources management: participatory research is more popular and it uses widely acceptable techniques for watershed planning and management including: rapid catchment assessment, soil and water conservation, degraded forest assessment, nurseries and planting, identification of trees’ uses, rural energy assessment, green enterprise development, wildlife reservation, and village resource management plans. agriculture: the next application is farmer participatory farming system research done by farmers in addressing crop farming, livestock farming, irrigation system, and market network for their products. equity and inclusive development: another application focuses on a research on policy level to sustain the growth momentum in order to ensure inclusive development, where benefits of economic development are to percolate to the poor and under privileged with an objective to boot economic growth along with augmenting employment opportunities, alleviating poverty and ensuring regional equity and prosperity. 398 afr. j. environ. econ. manage. health and nutrition: health and nutrition monitoring is the fourth important application of participatory research which focuses on reproductive health, disease problem ranking, healthcare providers and costs, planning health projects, food security, nutrition assessment and monitoring, and water and sanitation assessment, planning and location. all these applications are positive evidences that are scaled and used by various organizations and individuals, who have been engaged in training and appraisal, to respond to demand and their own sense of priorities and experiences. the use of monitoring and evaluation was found to be limited and academic researchers have been slow to recognize what was happening in practical application of participatory research. these methods have usually proved more reliable in information flow arguments and discussions taking place among the villagers, outsiders and between both villagers and outsiders. however, the success and failure much depend on the behaviors and attitudes of the outsiders whether or not they have the time, patience and will to get closer to reality. any way, reversals of modes like from closed to open, from verbal to visual, from counting to comparing, and reversals of dominance as from extracting to empowering, reserve to rapport and from tedium to fun are some important changes in the research that was brought out by participatory research. in nepal and other developing countries, like india and the middle east countries, it proved more useful to carry out the research and development activities for conservation of environmental and natural resources and livelihood improvement of rural communities. besides these, policy research and change, personal behavior, attitudes and learning, farming system research, quality assurance, inclusive growth and empowerment, and substituting for survey are potential fields to participatory research in nepal for achieving flexibility by empowering people, learning to love change, becoming obsessed with listening, deferring to the front line, and building system for a world turned upside down. therefore, we have challenged the locals to further develop and disseminate approaches and methods to promote their own analysis and make their own needs and priorities known to scientists. usage of participatory methods in karnali watershed area since 1990s, participatory approaches and methods of research and development have been widely used in many parts of the country. particularly, this has been done in rural resources development and management practices through community based organizations and users’ groups at community level, and it has become more popular in the world as the model of participatory development, such as community forestry and water mahamoudou 399 table 1. perceived challenges for ensuring people’s participation. challenges key informants no. % lack of ownership feeling 12 19.57 low level of public awareness 9 14.28 unclear policy 7 11.11 growing unemployment 9 14.28 lack of technical assistance 7 11.11 lack of social mobilization 7 11.11 lack of need basis plan 11 17.46 total 63 100 source: field survey (2010). resource management through users’ groups. many gainful evidences indicate that rural communities have benefited from using participatory methods to development for improving their farming system, conserving their available resources and preparing their own plan based on their own choices. however, it has little effects in karnali watershed area. there are many reasons behind this which are discussed here with resolutions in brief. low level of people’s participation the onward fifth five year plan (1975 to 1980) was initiated with the central objective of institutionalization of people’s initiative in all development plans. the decentralization act of 1982 was enacted in the mid 1980s. however, in practice, particularly, in the karnali watershed area, it is often seen that both the government and nongovernmental organizations, involved in the local resource development, did not promote people’s participation, rather the local people were kept away from taking active part in development. in the most cases, local people had not been given the choice to take decision for their development. even though the financial authority was kept by the central government, the role of government was still found as the body in-charge of development and welfare of the local people. further, there is growing number of middlemen who have bred corruption and mismanagement of available resources. thus, only a small number of elite people are the beneficiaries of the development activities. the local people (real beneficiaries) are always kept far from the mainstream of development. it is evinced that the drawbacks of top-down development approach have largely been attributed to promote the people’s participation in local level development. sundaram (1997) has nicely noted that the government mechanism in asian countries, like nepal and india, hardly want to enhance the people’s participation in the real term. it may be seen from table 1 that the unclear government policy towards the participatory development, owing to the lack of strong sense of ownership feeling of local people on the ongoing development programs, was observed as the main challenges for increasing people’s participation in the area. the skewed distribution of resources has also been hampering people’s participation and the major bulk of resources are to be occupied by a small number of elites. about 11% of key informants have noticed the lack of appropriate social mobilization policies where people are educated, organized, motivated and enabled to undertake social enquiry and analysis for understanding their life situation and taking decisions and actions to change it for their well-being. as a result, 14% of the key informants further noted the dominant role of resource rich family on community-based organizations, which is further responsible for mass unemployment, and low level of local participation. moreover, people’s involvement has been considered to volunteer a form in the implementation stage of local development in the region. thus, it is the central government authority that takes almost all development decisions. consequently, the local needs have not been taken seriously at the time of programming. all these make the people to be less willing to participate in development activities in karnali watershed area. among the various issues, the most remarkable was observed to be technological drawbacks. the present use of technology for local resource mobilization is not appropriate and adequate. the level of participation has also been observed to vary among the ethnic groups based on resource base and priorities. therefore, an appropriate need-based and time specific strategic intervention in various stages is of utmost importance for the mobilization of local resources. on the whole, the imposition development from the top level without due consultancy from the village level failed to activate people’s participation in local resource mobilization. so, there is a need to look at the opinion and idea of the local people in utilizing the local resources effectively at the local level. it shows that people’s participation is found as the most effective social measure for empowerment of local communities and the only way by which backwardness of the area can be eradicated (pokhrel, 2004). it further permits to note that genuine public participation of people at the centre of development is the hallmark of eco-development. this is so, because it is an endogenous development process in which local people themselves assume the responsibility to manage their resources, define their needs, goals and aspiration, and to make decision affecting their well being and sustainable development. people’s participation is the process by which the rural poor would be able to identify their needs, share in design, implementation and evaluation of the participatory action for resource development (fao, 1990). some important activities that have been conducted by local communities for the conservation and management of natural and livelihood resources in karnali watershed area are presented in the following photographs (figures 1, 2a, 2b, 2c and 2d). 400 afr. j. environ. econ. manage. figure 2a. briefing of project activities with authors at the field office of the local ngo. figure 2d. discussion with beneficiary women of organic farming. figure 2b. meeting with beneficiary farmers of jumla. figure 2c. discussion with inrm user groups in surkhet valley. under such circumstances, the collective efforts of locals become self -organizing and self-sustaining in unleashing the potential of the local community and in meeting their inner urges and preferences with regard to development through self-reliance. the gravity of such development is to be self -generated, selforganized and self-sustained at the local level (gultung, 1980; charles, 1987; bajpai, 1998). thus, the insight development of the locals is most important. in doing so, there is an immediate need of resource knowledge to the local people which is further possible through people’s resource right (joshi, 2002). of course, to ensure people’s involvement in ecodevelopment activities of the concerned communities, they must have a sense of belonging to the local and natural resources that is the main process of gaining power by real actors. therefore, efforts are needed to promote the capabilities of local and indigenous institutions for making their functions more productive. this is possible only by strengthening such community institutions through providing sufficient autonomy as part of the organization involved in resource development. so, if local communities are to become principal actors in promoting their social well-being, they must be able to give vision and focus to their endeavors. it is indicative that devolution of power from the top to bottom (that is, grassroots) for capacity building with generation, application and diffusion of knowledge through a unified approach social change at the grassroots level could be achieved, and the resource poor could participate directly in efforts to improve their own well being. furthermore, their participation must be substantive and creative in order to enhance the development of material resources and technologies with regard to serving and matching its real needs. it is clear that ecodevelopment can only change the potential beneficiaries into functional groups. thus, government authority should be given a priority for ushering in people’s involvement. moreover, it needs to be a strong support of finance, policy and technical inputs from the government to local institutions for enabling their capacity with regard to resource mobilization. most importantly, government authorities need to establish broad eco-technological strategies in partnership with key stakeholders. evidences suggest that in the national mahamoudou 401 table 2. need of people’s participation for eco-development. perceived needs key informants no. % need basis/bottom up planning 19 30.15 ownership feeling 10 15.87 coordination between outsider and insiders 6 9.52 verification of implementing program 5 7.93 development of indigenous knowledge 6 9.52 organized/collective efforts 8 12.60 institutionalization 9 14.28 total 63 100 source: field survey (2010). level, local resources user groups and self-managed enterprises are emerging and functioning successfully. it proves that such grassroots organizations have great potential in those regions like the karnali watershed area where environmental, as well as development challenges are immense. for this purpose, local people (that is, primary beneficiaries) need to form their own organization different from that of the primary local unit for mobilizing resources to acquire ownership of resource utilization and management overtime and assume full responsibility on decision making and implementation of community based resource development activities (bavuskar, 1999; sethi, 2003; world bank, 2003). to achieve this, first, efforts need to be made to access the attitudes, behaviors and priorities of the locals with deep understanding of the group dynamics and heterogeneous characters of the society. secondly, steps should be taken to identify and support formal and informal groups and institution. so, special attention must be given to explore the resource and resource rights. it is necessary thus to ensure ecoeducation of people to make them able to understand their needs and problems. thirdly, investment has to be made in institutional capacity development which will further enhance the internal capabilities of local units. such institutions should be considered as the form of public services. therefore, local authorities must be strengthened to secure common benefits through accepting mutual obligation on resource mobilization. it shows that people’s involvement in resource development is necessarily desirable for a need base bottom-up planning, strong feeling of ownership on local resources, development of indigenous technology and promotion of collective action of the grassroots people in the region. it can further be noted that coordination among and between the line agencies who are involved in community based resource development, correction and verification of their implementation procedures, and institutionalization of such community based organization are also possible at the micro level by adopting eco-development strategy (table 2). thus, people’s participation is essential to replace a relationship based on dominance and competition with that based on reciprocity and collaboration, and to promote solidarity and unity of purpose among all members of the community. however, several challenges are ahead in ensuring people’s participation in the study region. in most cases, the mechanisms involved for this purpose have failed to reach the grassroots level. the possible reasons might be over dependence on foreign aid and central controlled programs. therefore, need base and resource base planning with right advocacy skill development and technical dissemination should be emphasized on government policy. at the moment, local efforts should be institutionalized to empower themselves with regard to income generation, social change, environment management and ecological balance of community life in the region. emphasis should also be given to human resource development in order to promote the indigenous resource management system. such indigenous systems have significant role on conservation of forest and other natural resources. for example, community forest user groups have proved themselves to be more responsible and reliable than the government officials. so, the participation of user groups and others who have rights in decision-making process about utilization and conservation of local and natural resources is what is needed now with respect to the region’s sustainable development. therefore, cultural, social and ecological dimensions should be prioritized in the implication process of integrated eco-development strategies in karnali watershed area, because the gravity of cultural values, social norms and people’s perception is much more on the control mechanism that acts for resource utilization and management. in short, the current emphasis should be on policies for strengthening indigenous resource management systems and institutionalizing such systems in order to succeed in the integrated eco-development model at the village level. eco-development practices it is true that in karnali region, the traditional farming system might have some little effect on ecological stability, so long as the population of man and his animals do not exceed the carrying capacity of the environment, but when they do, there has been consequent pressure on land, less suitable for farming, depletion of forest resources, erosion, and environmental destruction particularly of the marginal and sensitive areas. lack of ecological consideration in development activities has also been intensified by environmental assaults and the life support systems have undergone diminishment. thus, there is need to modify current land use policies that can make the region available for ecologically sound and sustainable agro-farming with man-environment kinship needs to be restored in order to link the socio-economic interests of the local people with the sustainable management of natural resources for environmental stability and ecological security. therefore, shift in priorities, change in implementation methods, modification in the planning process, and examination in resource allocation patterns are needed for maximizing the economic returns of development without ecological destruction. due to the wide range of topography, climatic elements, soil characteristics, and socio-economic condition, the karnali watershed area presents very special ecological features having more than 75% of terrain rugged and steep, and the unit cost of infrastructure development is high, while returns are relatively low. the ever growing human demands, faulty method of cultivation, and development patterns have brought considerable damage to fragile eco-systems in the area. in this regard, an integrated approach of development and conservation by involving local people in all processes and steppes could be effective to promote the quality of life of the people in the area, because eco-development refers to sustainable development in which all development activities are performed in such a way that regional ecological balance can be maintained. practically, environmental planning is done for regional (meso) and rural (micro) level development with a rational use of the resources and application of technological styles (bhati, 1985; guleria, 1987; peet, 1989). through the principal objectives of the development strategies, protection of the available resources, regeneration of resources and development of human knowledge could enhance the quality of environment and the economy of the area. furthermore, through social development with respect to maximizing the productivity of both the natural and human resources, and through preventive planning and development policy, many adverse ecological consequences could be avoided and the interest of the local people to environment management could be enhanced. finally, people will feel comfortable with their environment and process of development. therefore, such development 402 afr. j. environ. econ. manage. approach would make people adopt the integrated conservation and development in which people can decide their real goals and objectives for the proper utilization of local and natural resources. at present, it is shaping into people’s movement, and the active people’s participation is envisaged from the grassroots rather than from the remote control exercised by the corporate executives. consequently, a fair hope that people can decide what their priorities of work are for conservation and development is expected. thus, it is necessary to give top priority to the livelihood of the locals for designing such development strategies. this can be achieved through social planning norms that promote an organized collective effort of local people at the community level. all these are possible on a resourcebase planning unit which may be a watershed unit, be it macro or micro, but more than the political boundary. it also enables the integration of environment management and socio-economic development by adopting watershed management approach at the village level. it shows that the holistic vision of the proposed development strategy is essential for the integration of the environment into development practice with regards to rational utilization of local resources and minimization of the environmental hazards. watershed management it is clear that the plans of the administrative units and central government failed to address the real needs of the area and the utilization of regional resources in karnali watershed area. this is mainly due to topdown planning for local development and less interest of local people towards the government launched program. further selection of the planning unit which is based on political boundary is also the factor responsible for ignoring the ecological bases of development. thus, a socially desirable, economically viable and ecologically sound development approach is required to promote harmonious relationship between development and ecology. it is possible, to adopt only the watershed management strategy that prove to be an appropriate development path for the area. pokhrel (2009) has noted that watershed management strategy should be the core for development activities, and there is need to popularize it in himalayan region. some other case studies have also shown that the integrated watershed development approach is more practicable and it evolves a compact technical, economical, ecological and geographical unit of planning for resource utilization and conservation (goi, 1988; grewel et al., 2001; narayan, 1993). thus, in karnali watershed area, watershed management approach could play a significant role in increasing the productivity of the total resources. watershed is a very appropriate spatial unit for examining the physical aspects of karnali and its tributary rivers with mahamoudou 403 table 3. number and area of watersheds. catchment watersheds sub watersheds micro watersheds basins area (km 2 ) per area (km 2 ) no. no. area (km 2 ) no. area (km 2 ) watershed karnali 42,890 7 6,127 15 2,859 90 476.55 babai 3,270 2 1,635 6 545 27 121.11 rapti 6,500 5 1,300 10 1,083 42 240.71 total 43,260 14 3,090 31 1,395 159 272 source: sharma (1977); field survey (2010). their size, which may vary from small to some large catchment areas. so, watershed is a logical planning unit for evaluating the biophysical linkages of upstream and downstream activities of the basin. it is only the sixth fiveyear plan introduced as an integrated development approach in nepal as the synonymous of soil and water conservation, but the failure of large scale development programs and the realization of the importance of interlink ages between resource productivity and sustained increase in rural income have led to the shift in watershed management approach with the prime focus of integrating environment and development in regional level. in operational level, it made efforts to bring all concerned institutions into single window system through interdisciplinary approach. recently, it is more anthropoeco-centric and community based rather than technology based, thereby leading empowerment and self-reliance of the primary stakeholders as an entry point for outsiders to understand local environment, and for making development plan in a comprehensive way. however, evidences show that macro watershed management programs in nepal have some remarkable failures, in that many watersheds are still being degraded. particularly, in the karnali watershed area, large scale programs have rarely been successful in conservation and utilization of local and natural resources with people’s participation. the degraded watersheds are further worsening due to over intervention of outside technical teams (shah, 2000). thus, social mobilization is needed to enhance the success of watershed development approach for the strong feeling of belongingness of local people towards the ongoing development and conservation programs. this is possible only by adopting micro-watershed development approach that can provide an appropriate path way for eco-development. further, it would also be helpful in devising location specific solutions that may emerge by resolving activities that are conflicting (head reach-tail end beneficiaries), and build-on complementary activities (forestation and soil conservation in hill and mountain regions enables better productivity in the tarai region). thus, emphasis should be shifted from large to small watershed areas in which both management of environment and socio-economic development can be integrated (agarwal, 2003). therefore, an effort is made here to delineate estimated watersheds, sub watersheds, and micro watersheds in the region. based on the drainage pattern, transport network, population statistics and relief features, the whole karnali-west rapti basin (43,260 km 2 ) was divided into four hierarchical orders: resource regions, macro watersheds, sub watersheds and micro watershed. so, 14 macro watersheds, 31 sub watersheds and 159 micro watersheds were identified as the unit of eco-development planning in the area (table 3). these micro watershed units can further be subdivided into small and mini watershed units varying in size (50 km 2 ) for different land use purposes. therefore, it is the micro watershed development strategy that could solve the problem of the five ‘es’: employment, economy, ecology, expert and equity, and would then be ushered in eco-development with a sharp focus on resource conservation and poverty alleviation in the region. furthermore, the institutional and technical co-ordination amongst the involved agencies would also be strengthened in the region (figure 3). as the concept of integrated eco-development refers to sustainable resource development, it requires local initiations for integrating the environmental issues into socio-economic development. this development approach can make a substantial contribution to resource management at the micro level incorporating biophysical, technological, social, political and other variables which account for resource utilization and conservation. further, such type of development approach maps the complex connection, direct-indirect effects, feedback loops, and reciprocal relations and effects of environmental and human resources to each other. experiences have shown that local institutions in essence, community resource user groups are so effective in conservation and development of natural resources at regional and national levels in the country. even in many parts of the karnali watershed area, especially in the hills, such user groups have also exhibited extra-talents in forest resource protection, utilization and management. thus, it is strongly felt that a micro level resource utilization and conservation model is necessary in the precise and synthetic form that would increase the productivity of environmental resources in a sustainable manner. such grassroots model can as an aspect of bottom-up strategy call for mass action at the micro level (that is, village level). so, the kingpin of the natural resource 404 afr. j. environ. econ. manage. figure 3. watershed management in karnali watershed area. development strategy of karnali watershed area is selfreliance on resource mobilization by using indigenous knowledge and experiences. thus, the right mix of traditional knowledge would be a winning combination of resource development. the central thrust of participatory development has to integrate development and conservation, government authorities and local beneficiaries, and coordination of the involved institutions between the decision making and implementation level and that of the micro watershed level. further, such adaptive model of resource management focuses on environmental feedback to shape policy. thus, the model explicitly considers social learning and institutional development. under such provision, large numbers of community based organizations would have evolved out of the region, and would be able to develop locally suitable technology, appropriate policy feedback and strategic clarity for resource development and conservation. better information system, participatory monitoring and systematic implementation of resource mobilization will also evolve through local initiations. finally, a specific technique would be modeled against the top-down tendencies for resource based regional development planning in karnali watershed area and in nepal in general. for this purpose, it is necessary to build-up local capacity for the total reforms of institutions in order to change the environmental policies in different orders. the principal concepts and components of this grassroots development model are: (i) formulating policy, strategy and programming the project based on the resource knowledge of the local people and an application of a suitable technology. thus, it has to have a local base including people, traditions and indigenous institutions. (ii) implementation of resource development activities through people’s involvement to strengthen local organizations and to bring about positive change in the local environment. (iii) participatory monitoring system with a view to avoid previous drawbacks of resource development planning at the micro level. thus, such innovative model can eventually lead to a district, as well as village level conservation and development plans. further, such model could successively imply that the local organizations have to control the local and natural resources, adopt a sustainable pattern of development and avail appropriate technologies in subsequently distributing local resources mahamoudou 405 amongst beneficiaries on an equitable basis. therefore, government authorities need to develop suitable methodology and guideline in order to ensure people’s participation and facilitate local organizations for the process of institutionalization in the proper way. similarly, to provide some financial support in the form of seed money is also needed. to build up local capabilities by imparting training and techniques at the local level is also essential from the government side. hence, it should be emphasized that the catalytic role of government is to galvanize the people to initiate resource development actions according to their priorities at self reliance. in this regard, district development committee (ddc) and village development committee (vdc) as the authority of government need to make a framework, in which this model may function and evolve. to achieve this, there is need to modify outside intervention for the dynamics of local institutions. actors, like non-government organizations, should collaborate with resource owned communities to develop the integrated micro level model, and explore and exhibit relevant alternatives that would stimulate the development of new resource management institutions (saravanan, 2001). conclusion it is evident that such participatory resource-based research and development model enables both the local people and collaborating authorities to learn about each other (their goals, knowledge and techniques) and finally make development efforts that are socially desirable and ecologically suitable. all these imply far-reaching changes and cooperation among and between the beneficiaries with respect to up-grading of skills and adaptation of new technologies for community based resource utilization and management in karnali watershed area. references agarwal sk (2003). integrated watershed development: technology based model for rural development, kurukshetra. 51(12): 49-57. bajpai pk (1998). people’s participation in development: a critical analysis, in s.p. srivastava (ed).the development debate: critical perspectives. rawat publishers, jaipur. baviskar a (1999). participating in eco-development: the case of the great himalayan national park. in jeffery r, sundar n (eds.). a new moral economy for india’s forests? discourses of community participation, sage publication, new delhi. bhati jp, swarup r (1985). why eco-development planning fails in the himalayas: some problems and policy issues. in singh tv, kaur j (ed.) integrated mountain development, himalayan books, new delhi. chambers r (1995). rural appraisal: rapid relaxed and participatory. in amitava m (eds.) participatory rural appraisal methods and applications in rural planning, vikash publishing house, new delhi. chambers r (1989). farmer first: farmer innovation and agricultural research, intermediate technology publications, london. charles kj (1997). what is development? in george kk, nair vs jacob j (eds). economics, development and the quest for alternatives. concept publishing company, new delhi. fao (1990) farming systems development, food and agriculture organization of the united nations, rome. gultung j (1980). self-reliance – a strategy for development, bogle liovertune publications, london. goi (1988). integrated watershed development project (hills): an analytical overview and future strategies.national workshop on watershed approach to rain fed farming: strategies for integrated watershed development for hill regions, rain fed farming system, government of india, vigyan bhawan, n delhi. grewel as, jai tc (2001). poverty alleviation and resource conservation through integrated watershed management in a fragile foot-hill ecosystem. in stott de,. mohtar rh, steinhardit gc (eds) sustaining the global farm. usda-ars national soil erosion research laboratory, purdue. guleria as (1987). a strategy for eco-development in himalayan region: watershed approach in pangtey yps (ed) western himalaya: environment, problems and development, gyanodaya prakashan, nainital. joshi ap (2002). resource rights – community domain, kurukshetra, 50(7): 12-14. narayan vd (1993). watershed management: concept and framework in soil and water conservation research, indian council of agricultural research, new delhi. peet r (1989). new models of environment and resources. in peet r, thrift n (ed) new models in geography, unwin hyman ltd., london. pokhrel kp (2009b). climate change adaptation: strategy for ecological restoration and livelihood security, voice, 1(1): 5-12. pokhrel kp (2004). local efforts on resource conservation and ecodevelopment: a case study of mid western development region nepal, unpublished. ph.d. thesis, bhu, india. pokhrel kp (2009a). environment and development practice in nepal: a geographical analysis, edrc, banke, nepalgunj. rhoades re (1990). the coming revolution in methods for rural development research, users’ perspective network (upward), international potato centre (cip), manila. saravanan vs (2001). institutionalizing community based watershed management in india: institutional elements for sustainability national council of applied economic research (ncaer), new delhi. sethi s (2003). stakeholders’ participation in local level planning and development, kurushetra, 53(3): 26-30. shah p (2000). participatory watershed management in india: the experience of the aga khan rural support program. in ian s, john t (ed.) beyond farmer first-rural people’s knowledge, agricultural research and extension practice, intermediate technology publications ltd., london. sundaram kv (1997). development from within: rethinking on an alternative development path, in george kk, nair vs, jacob j (ed.) economics development and the quest for alternatives, concept publishing company, new delhi. world bank (2003). world development report, sustainable development in a dynamic world, transforming institutions, growth, and quality of life, the world bank and oxford university press, new york. 1 in ternationa l scholars journa ls african journal of environmental economics and management issn 2375-0707 vol. 10 (3), pp. 001-002, march, 2022. available online at www.internationalscholarsjournals.org © international scholars journals author(s) retain the copyright of this article. short communication adaptive success index: a criterion for identifying most important species diogo s. b. rocha*, leilton s. damascena and flávio frança *departamento de ciências biológicas, laboratório de taxonomia vegetal, universidade estadual de feira de santana (uefs), bahia, brasil. accepted 11 october, 2021 this article introduces the adaptive success index (asi) as a criterion for deciding which species are actually important in a given list of species either based on the importance value index (ivi) or on the cover value index (cvi). key words: adaptive success index (asi), importance value index (ivi), cover value index (cvi). introduction phytosociology is the analysis of co-inhabitance, structure and constitution of groups of plants as well as the processes that favor continuity or change within a group of plants in time-space (martins, 2004). description of communities through phytosociology has evolved along with ecology towards a quantitative approach. attributes such as dominance, frequency and covering are parameters used in order to describe communities in numbers (moreira, 2007). importance value index (ivi) and cover value index (cvi) only classify species according to their importance, failing to present useful criteria when it comes to assessing the importance of a group of species within a given community. in addressing this problem, this work aims at proposing criteria that can be used to classify species that present more significant adaptive success within a community. assuming that ivi is the result of adding three relative parameters – density, dominance and frequency, the result is inversely proportional to pielou’s j’ equability, which assesses heterogeneity. ivi is inversely proportional to j’ because if the first is very high it means vegetation is more homogeneous (müeller-dombois and ellemberg, 1974). adaptive success index is based on the premise that species within the most successful *corresponding author. e-mail: diogosbr@gmail.com. group are more adapted to the environment under study. enunciation adaptive success index (asiivi) is reached through the ratio between the importance value indexes (ivi) of each species and the triple of the equability (j’) in the sampled area. j’ is multiplied by three because the ivi is the result of the sum of the three relative values. asiivi = ivii/(3j’) where: ivii is the importance value index of the ‘ith’ species. species presenting an asi value equal or above the average asi were considered to be the most successful ones ecologically, which is the simple arithmetic average of the asi for each species in the sampled area. average asi ivi = σ asi ivi/n where n is the number of species. considering that the ivi uses the frequency of the sampled species in its construction, this fact is directly influenced by the size of the sample (moreira, 2007). we propose an alternative to use the adaptive success index (asi) based on the cover value index (cvi). 2 in this case the adaptive success index will be calculated through the ratio between the cvi and the double of the value of j’ since the cvi value is the sum of these two relative values. asic=ivci/(2j’) species presenting an asic above or equal to average asic were considered to be the most successful ones ecologically, which is the simple arithmetic average of the asic. average asi=σisac/n where n= number of species. conclusion and uses adaptive success indexes, particularly the one based on the vegetation cover, can provide the analyses of vegetation indexes with a quantitative approach on the contribution of vegetation structure to reflectance values. this analysis might prove fundamental to the classification of vegetation and to the understanding of ecological dynamics. since asi classifies the most important species based on their importance indexes (ivi and cvi), significant contribution of a species to the construction of local vegetation physiognomy can be accessed. asi can contribute to comparisons among different areas, hence helping classify vegetation through floristic composition. one can compare groups formed by species with more significant adaptive success among areas under study along with grouping analysis and infer on the similarity among certain areas. references martins fr (2004). o papel da fitossociologia na conservação e na bioprospecção. anais do 55º congresso nacional de botância: simpósios, palestras e mesas-redondas. sociedade botânica do brasil e universidade federal de viçosa, viçosa, edição em cd-r. moreira cm (2007). avaliação de métodos fitossociológicos através de simulações de amostragens numa parcela permanente de cerradão, na estação ecológica de assis, sp. msc. escola superior de agricultura luiz de queiroz, piracicaba, sp. müeller-dombois d, ellemberg h (1974). aims and methods of vegetation analysis. new york: wiley, p. 574. in ternationa l scholars journa ls african journal of environmental economics and management issn 2375-0707 vol. 3 (5), pp. 231-243, october, 2015. available online at www.internationalscholarsjournals.org © international scholars journals author(s) retain the copyright of this article. full length research paper assessment of factors influencing utilization and conservation of forest resources in kipini division of tana delta district, kenya olunga m.a1, kavoi m.m2and guthiga p.m3 1 land o lakes, peponi plaza, 2nd floor, block a, off peponi road, westlands, nairobi, kenya. 2 jomo kenyatta university of agriculture and technology, p.o. box 62000-00200, nairobi, kenya. 3 international livestock research institute, nairobi, kenya. accepted 28 june, 2015 forest resource utilization poses a challenge to the balance between fragile ecosystems and impoverished populations. as population increases, the demand for forest resources and the resultant degradation are expected to increase. many benefits can be derived from conservation initiatives. yet incidences of destruction by local communities are prevalent. this study examined the factors that influence utilization of forest products and attitudes of households towards conservation. the logit and negative binomial models were used for analysis. descriptive and factor analysis were used to assess the attitudes towards conservation. data was collected from 150 households in kipini division of tana delta district, kenya. logit model results showed that income, distance to the main road, management regime and occupation of the household head influence use of forest products. results from negative binomial regression showed that intensity of use of forest products is influenced by the management regime, occupation of household head, income and distance to the main road. the results of the descriptive and factor analysis indicated that the local community has negative attitude towards conservation of forests. these findings imply that conservation can be enhanced by creating awareness of forest benefits to the community and training them on energy saving charcoal burners. key words: forest use, intensity, attitudes, conservation, tana delta district. introduction natural resources form the bulk of resources that are important to many economies of the world in meeting economic and development needs. in these economies the majority of people are poor, they live in the rural areas, and are mainly dependent on agriculture or on natural resources and ecosystem services (world resources institute, 2005). the utilization of natural resources as a livelihood strategy is important especially to the communities residing adjacent to these resources *corresponding author. kavoi.muendo@gmail.com (sumati, 2006). such communities collect process and/or market various kinds of natural resources either as a predominant activity or as part of a diversified portfolio of livelihood strategies designed to spread and minimize specific risks (norfolk, 2004). forests, among the natural resources, have potentials and limitations for improving human welfare (angelsen and wunder, 2003). forests improve human welfare by providing a range of resources including timber, nontimber forest resources, and recreation. forests also supplement household income thus providing safety nets (neumann and hirsch 2000; pattanayak and sills, 2001). kavoi et al. 231 the poor however tend to destroy the environment by cutting down forests; overgrazing and cultivating marginal lands (world bank, 2012). the human activities affect soil nutrient content (peh et al., 2005) which in turn affect tree growth, forest cover, birds and invertebrates (peh et al., 2005; shahabuddin and kumar, 2006). further, grazing, removal of dead tree branches and dry leaves from the ground alter the nutrient dynamics while constant movement of cattle and humans erode the top soil layer (belsky and blumenthal, 2002) and browsing by goats and sheep affect re-growth, reduce perennial cover and increase exotic annual cover (yates et al., 2001). there are various management systems that can be used to conserve forests. these approaches take different organizational forms such as centralized management (command and control), where state agencies assume the lead role; decentralized management, where local communities are involved at varying levels; private management where private entities own and manage the resource; and co-management, where the state, local communities, and other actors share management functions, rights, and responsibilities (meinzen-dick and pradhan, 2002; mburu and birner, 2007). in kenya, the majority of the closed canopy forests (forest reserves) are managed by the kenya forest service (kfs) under the ministry of forestry and wildlife services. some closed canopy forests also known as national parks/ national reserves are managed by the kenya wildlife service (kws). on the other hand forests under the trust lands are managed by the local county councils in the ministry of local government holding the forests in trust for the local communities. lastly, there are some forests that are managed by private individuals or organizations under private ownership. these different management regimes have set rules governing forest resource extraction and forest use. in kipini division, the conservancy/private regime had the strictest rules governing access and extraction of resources. it did not allow neighbouring communities to extract any products from the forest. the kfs, on the other hand, allowed communities in the neighbourhood access to the forest and extraction of products. however, the extraction of products was limited to dead tree parts and other non-tree products. residents can also secure a licence to cut live trees for poles or timber. in the community management regime, however, extraction of forest products was allowed subject to permission from the administrative authorities who in turn usually consult with the community elders before allowing extraction. hence, in the first two regimes, a licence is required, while in the community regime consent from authorities was the main requirement. problem statement fao (2006) estimated the rate of forest destruction at 13 million hectares per year (for the period 1995-2005) with about 1.6 billion people relying on the forests, to some extent, for their livelihood. however, different forms of extraction may have different levels of impact (shaanker et al., 2004; shahabuddin and kumar, 2006). economies thus employ various resource management strategies in an attempt to address the challenge of balancing resource conservation and utilization. forests play many important roles in the ecosystem. they provide direct benefits to communities around them and act as habitat for various plant and animal species. tana delta forest is one of the most unique forests in kenya. the forest is home to numerous plants and animal species. it is host to 350 bird species; endangered marine turtles; two endangered primates namely the tana river red colobus and the crested mangabey monkey; hippopotamus; elephants and the nile crocodile. there are also various fish species in the coastal waters and fresh water river and ponds. the forest patches are endowed with mangrove and tropical forests especially along the tana river. the forests are therefore important to kenya because they comprise lowland evergreen riverine tropical forest types which are rare in kenya and even in africa, due to its biodiversity (karere et al, 2004 and owino et al., 2008). further, witu forest, in kipini division has a great potential for eco-tourism. the forest does not exist as one continuous forest block but as several blocks with one main block in kipini location and several other pocket forests of different sizes in kilelengwani and ozi locations. some of the tourist attractions offered by the forest include birdlife, mollusks, crustacea and crocodiles. despite its significance, the lower tana river forest (ltrf) complex currently faces serious threat. settlement into the forest has increased significantly in the last one decade owing to a number of factors (okello, 2011). new settlers clear the forest to make way for farming. at the same time the felling of trees for timber, building material, fuel wood and charcoal has increased with the increase in demand for these products (muoria et al., 2002; luke et al, 2005, owino et al., 2008). the problem is that the resultant conflicts in land use between agriculture and forestry, and the increased extraction and intensity of use of tree products have complicated the conservation of the ltrf complex. the level of forest use and the degree of reliance on forest products differ across households. the factors that condition a household’s reliance on a particular economic activity and on forest products in particular may vary. past studies (wells and mcshane, 2000; bawa et al., 2004 and volker and waibel, 2010) have pointed out that forest utilization is affected by factor resource endowment of the household, the household’s demographic and economic characteristics, and exogenous factors such as 232 afr. j. environ. econ. manage. markets, commodity prices and technologies. hence, understanding the factors that determine household’s activity choice and reliance on forest products is essential for both conservation and development-targeted policies. determining the attributes of a household that are related to dependence on the forest will help predict which households are likely targets for conservation. research methodology theoretical framework in the study area, markets for some of the forest products do not exist and/ or are imperfect; and if they exist, are characterized by high transaction costs. consider a farm household that makes production and consumption decisions jointly (de janvry et al., 1991), i.e., whose decisions are non-separable. this means that the household’s decisions about production (use of inputs, choice of activities and desired level of production) are affected by the consumption decisions/characteristics (consumer preferences, location and demographic composition). under these conditions, the household maximizes the utility from consumption of home produced, market and leisure goods subject to a production function and a set of constraints. thus, the household’s utilitymaximization problem can be expressed in a utility function as: hiqma h,mt,c,c(umaxu  (1) where; ca = consumption of home-produced goods, cm= consumption of market goods, tq = total time available to the household, mi = time spent on household production and off-farm wage earning (household labour supply) and hh = household characteristics subject to production constraint (equation 2), household’s income constraint (equation 3), household total time constraint (equation 4), market constraint (equation 5) and environment constraint (equation 6) expressed as: ),,( ajkfq  (2) ywmwjcajkfpcp iaamm  )),,(( (3) iha mlt  (4) 0ml ih  (5) 0qca  (6) where; q = the home output of both agricultural crops and forest products with f (.) being assumed to be increasing and concave in all its arguments j = labour k =capital a = other exogenous factors that affect production including property rights, local and national policy and technology among others pm = price of market goods, pa = market price of home-produced goods, w = wage rate and y= exogenous household income from non-wage and non-farm sources the lagrangian (l) equation for this optimization problem is given by: ][][])}),,({[);,,( iammia a hiama mjqccpiwmwjcajkfphmtccul   (7) the first order necessary conditions; 0)(        pp c l aaa (8) 0)(        ww t l j (9) 0     w l f pa (10) in equation 8, the first order necessary conditions shows that the price (pa) is a function of  while in equation 9 , the first order necessary conditions shows that wage rate (w) is dependent on . this implies that as long as the market environment constraints are binding, market prices (pa and w) cannot guide household decisionmaking because their market price is zero or very low in value. instead the household is guided by shadow prices (shown in parentheses in equations 8 and 9). equation 10 also shows that the value of the marginal product of labour is not equal to the market wage rate. shadow prices reflect the true opportunity cost and benefits. households will respond to them rather than market prices while making utility-maximizing choices (de janvry et al., 1991). it is the sign of γ/λ and θ/λ that determine the size of shadow prices and the relevant wage which would vary by household depending on whether a household is self-sufficient, net seller or net buyer of a produce or labour (sadouletandde janvry, 1995). these variations in prices and wages are caused by transaction costs in buying and selling, household preferences, production technology and access to employment oppor kavoi et al. 233 tunities. they are therefore included in the production function due to their influence on decision making in this case being maximizing utility of resource use. imperfections in the market here imply missing labor or credit markets. rural labor markets are not completely developed. although some labor transactions occur, the marginal value product of labor deviates from the market wage, implying that production and consumption decisions are non-separable. the marginal value product of labor is equated to a shadow wage that depends on household characteristics (household size and years of formal education of the household head) and other utilityrelated variables (collection time, distances to the forest and accessibility of the forest products). model specification: use of forest products use of forest products in this study refers to extraction of products from the forests e.g. fuel wood, medicinal herbs and thatching grass. to assess the use of products, respondents were asked whether they obtained any products from the forests in their neighborhoods or not. therefore the response variable in this case was binary choice that is a "yes" if the household collected products from the forest and "no" if it did not. the three most commonly used approaches to estimate such binary dependent variable regression models are (1) the linear probability model (lpm), (2) the logit, and (3) the probit. they are applicable in a wide variety of fields (gujarati, 2004). the lpm is not used in empirical research because it violates a major rule of probabilities that requires that the sum of the probabilities be equal to unity (wooldridge, 2002). the logit and probit models, however, guarantee that the estimated probabilities lie between the logical limit of 0 and 1 (wooldridge, 2002). hence, the logit and the probit models are the most frequently used models when the dependent variable is dichotomous (maddala, 2001; gujarati, 2004). gujarati (2004) argues that the probit and logit models are quite similar. they generate predicted probabilities that are almost identical. aldrich and nelson (1984) indicate that in practice these models yield estimated choice probabilities that differ by less than 0.02. the main difference between the logit and probit models is in the nature of their distribution which is captured by cumulative distribution function (cdf). probit has a normal distribution while logit has a logistic distribution which has slightly fatter tails than the normal distribution. the choice of probit versus logit regression therefore depends largely on the distribution assumption one makes. in practice many researchers choose the logit model because of its comparative mathematical simplicity (kirui, 2011). in this study, a logistic regression model is used to assess factors affecting the use of forest products by households. logistic regression following maddala (2001), the probability, p, that a household uses forest products is given by: e z e z p   1 (11) central to the use of logistic regression is the logit transformation of p given by z 2 1 ln        p p z (12) where;    adfzz ,, (13) z is a latent variable that takes the value of 1 if the household used forest products and 0 otherwise, f is a vector of farmer characteristics, d is a vector of farm level variables, a is a vector of asset endowment variables, and ε is the stochastic term assumed to have a logistic distribution. the empirical model estimated contains the following variables (letters in parenthesis indicate related category variables from the conceptual model): 1) farmer specific variables (f) = age, gender 2) farm specific variables (d) = distance to the forest from household, household size and distance to market 3) asset endowment variables (a): i. financial asset (income) ii. human capital (education) iii. social capital (group member) based on the above equation, the logistic regression model estimated in implicit functional form becomes; use of forest products (z) = f (lnage, distance from forest, farm size, household size, lnincome, market distance, occupation, education, group membership and regime) + e (14) intensity of use of forest products in order to assess the factors affecting the degree of use of forest products, this study specified the dependent variable as the number of head-loads harvested by a household in 2010/11. it therefore used the poisson and the negative binomial regression models to isolate the determinants of the degree of use because the dependent variable is a count data variable. these count variable models are suitable for dependent variables that are countably finite. count data are non-normal and hence are not well estimated by ols regression (maddala, 2001). the key models normally used to analyze count data include the poisson regression model (prm), the negative binomial regression model 234 afr. j. environ. econ. manage. (nbrm), the zero inflated poisson (zip) and the zero inflated negative binomial (zinb). poisson and negative binomial regression models are frequently used in estimating models with nonnegative integer dependent variables (greene, 2008). the zip and zinb regression models are specifically used to account for the frequency of zero counts (i.e. when there are more zeros than would be expected in either a poisson or negative binomial model). the study identified only few zero counts therefore never warranted the need for zip and zinb. the results of nbrm is discussed in this study since the response variables were nonnegative integers and the poisson regression model, which was the first stage in analyzing count data, displayed over-dispersion. pearson chi-square ratio test (pearson chi-square divided by degrees of freedom) was conducted to check whether poisson model fitted the data well. under this test, under-dispersion or over-dispersion occurs when the ratio is less than 0.8 or greater than 1.2 respectively. in that case, the negative binomial is recommended (greene, 2008). in this study, the test detected overdispersion hence negative binomial regression model (nbrm) was applied. nbrm model has the additional advantage in that it relaxes the poisson regression model’s assumption of equivalence of mean and variance. following greene (2008), the negative binomial model is written as: )'exp(),xy(e ii  (15) the model requires that;        xxxiyi  expexp1var (16) where x’ is a vector of explanatory variables similar to those included in the model, the β refers to the variable coefficients and α is the constant. hence the estimated nbrm is specified as: number of head-loads (z) = f (lnage, gender of household head, regime, distance from forest, household size, lnincome, occupation, lnfsize, education, group membership) + e (17) attitude towards forest conservation to analyse the peoples’attitude towards an issue, two main approaches used include descriptive statistics and inferential statistics. the descriptive statistics includes summing up of the responses and obtaining a scoreorusing the percentage of respondents in a given likert scale category (shibia, 2010)or scale averages for the particular question responses (dolisca et al., 2007 and rishi , 2007). the second method uses factor analysis (dolisca et al., 2007). some studies use a combination of descriptive statistics and inferential approaches (dolisca et al., 2007). in this study, a combination of descriptive and inferential statistics was used to examine household’s attitudes towards conservation. descriptive statistics (percentages and mean scores) were used to describe respondents’ attitude towards forest conservation. on the other hand, factor analysis was used to identify latent dimensions underlying the different variables that measured respondents’ attitudes towards conservation. responses to twelve five-point likert-type scale items were subjected to a principal component factor analysis with varimax rotation. the factors were subjected to the kaiser-meyer-oklin and bartlett’s test (kmo and bartlett’s test) to determine the sampling adequacy. according to the test, samples that score above 0.7 are considered reliable for policy-related decision-making while those below 0.7 are considered unreliable. the above procedures were adopted for this study and used to discuss the attitude towards forest conservation. data and variables this study used data collected from households in kipini division of tana delta district. the division has three locations namely kipini, ozi and kilelengwani. each location is further divided into two sub-locations. each sub-location has several villages of varying household populations. multi-stage sampling technique was used to select a representative sample from the population for interviews. first, the three locations were purposively selected. this was because each location represented a different forest management regime. a list of all villages in each location was then obtained with the help of the local administrators.the villages were clustered into two categories based on proximity to the forest. six of the villages selected were close to the forest (distance of 05km) while the other four villages were far from the forest (distance 6-10km). a total of ten villages out of seventy villages were selected. a list of all households in the selected villages was then drawn. the population sizes of each of the locationswereused to arrive at the number of households interviewed in each location. hence the study sampled the respondents from the locations using thepopulation proportions.the division statistics based on the 2009 census estimates showed that kipini location had approximately 4000 households while kilelengwani location had approximately 2500 households and ozi location had approximately 400 households. this procedure resulted in 72 households in kipini location, 48 households in kilelengwani location and 30 households in ozi location. overall 150 respondents/ households were interviewed. data was collected in each of the households through personal interviews using a pre-tested questionnaire. the household head or spouse was selected forinterviewin kavoi et al. 235 each case. the data collected included household/ respondent characteristics and location characteristics. from this data the following model variables were obtained: use of forest products: this was a binary choice variable (1=a household extracts products from the forest and0=otherwise) that established whether a household collected any products from the forest or not. it covered the period between june 2010 and july 2011. age: is a continuous variable and was measured in years. age was expected to have a negative effect on use of forests considering majority of respondents were in their youthful stage. distance from forest edge:this was a continuous variable measured in kilometers. the proximity to the forests makes households inherently dependent on them due to accessibility and availability of the resources. distance from forest affects access to the forest for getting forest products and also increases costs in terms of time spent to walk to the forest and to gather fuel wood and other products in the forest. this might result in a larger proportion of the population of a village using fuel wood from the forest. distance from the forest edge was expected to negatively influence respondents’ decision to use resources. land size: this was a continuous variable measured in acres. land holding is a form of physical capital that a household possesses. it is expected that the likelihood of resource use would be less for households with large tracks of land. households with more land are likely to have access to farm fuel in the form of crop residue or fallow/unutilized land areas/ area of land under trees or grow trees on their land and therefore they are likely to be less dependent on fuel wood from the forest. household size: refers to the number of members in a given household. household size was expected to positively influence use of forest products. households with many members are expected to need more fuel wood for cooking and for construction of houses. income: this variable forms part of the financial capital owned by a household from all possible income generation sources that they were engaged in including remittances. it was measured as total income earned by household from various sources in a year (june 2010 july 2011). households working in non-farm jobs such as business or salaried employment should depend less on the forest for their income and will consequently need to clear less forest to meet their needs. when households diversify their income generating activities other than depending on forest products their tendency to rely on forests are likely to decline. this can slow down economic pressure to extract products from forests for sale to support their families; or generate resources that can be used to purchase inputs such as fertilizers; labor saving technologies or investments in activities that promote sustainable practices in natural resources management. distance to market: was measured in kilometres. respondents in villages closer to market places are more likely to allocate labor to the extraction of forest products, such as medicinal herbs, seeds and nuts for sale in the local market. hence households living close to a market have greater incentives to extract and sell forest products as their income source. thus market distance was expected to negatively influence the use of forest products. education: was measured as the number of years a respondent spent in formal schooling. the number of years of education of a respondent influences their level of understanding and decision making ability. a respondent with more years of formal education is likely to have access to alternative employment opportunities hence reducing the level of dependency on forest due to possibility of access to alternative fuel sources. regime: was measured as a categorical variable as earlier defined. the regimes influence the level of resource use through lack of enforcement and ill-defined property rights and corrupt governance structures. therefore regime was expected to negatively influence use of forest products. empirical results and discussions descriptive statistics results the results of the descriptive statistics (table 4.1) show that age of the respondents ranged from 20 to 100 years, with the mean age being 44 years and the mean household size was 4 members (olunga, 2013). the overall mean of fuelwood head-loads collected was 178 per year and the regime with the largest mean of headloads was community regime (309 head-loads/year) while that with the lowest mean of head-loads was the kfs regime (112 head-loads). mean years of formal education was 6.8. of the interviewed households, 117 (78% percent) were males while 33 (22 percent) were females. mobile phones were owned by 78 respondents (52 percent). distance to the main road was on average, 23.8 kilometers indicating that most households were located in the interior. the mean number of forest benefits known to respondents was about 11. of the 150 respondents, 125 (83.3 percent) were practicing farming as their main occupation. results also showed that 72 (48 percent) of the respondents belonged to a group(s) that engage in conservation activities. household mean income per annum was ksh. 21814.06. the respondents in the kfs regime had the highest incomes compared to those from the community and private/ conservancy regime. there were significant differences between variable responses in the three regimes with respect to farmerspecific, farm-level and asset endowment characteristics (olunga, 2013). specifically, there were significant differ 236 afr. j. environ. econ. manage. table 4.1 summary statistics of variables used in the poisson regressions model. private kfs community overall variable mean std. dev mean std. dev mean std. dev mean std. dev gender of household head (1=male 0=female) 0.8 0.38 0.7 0.44 0.8 0.4 0.8 0.42 age of household head (years) 44 11.75 45.1 11.21 41.1 17.65 44 12.71 household size (count) 4.3 2.15 3.9 1.98 3.7 2.66 4 2.17 forest benefits known (count) 8.8 3 12.3 5 9.9 5 10.7 5 group membership (1=yes, 0=no) 0.6 0.5 0.4 0.5 0.3 0.49 0.5 0.5 group members with farm forest (count) 0.48 0.5 0.29 0.46 0.19 0.4 0.34 0.48 total income of household (‘000) 27.1 34.0 22.4 33.2 9.5 13.0 21.8 31.5 total land size (acres) 7.9 4.78 9.6 4.1 5.8 3.63 8.3 4.47 main occupation of household head 0.9 0.32 0.8 0.41 0.8 0.37 0.8 0.37 distance from forest (km) 3.3 2.06 4 2.37 1.9 0.58 3.4 2.17 use forest products (1=yes, 0=no) 0.5 0.5 0.4 0.49 1 0.2 0.5 0.5 distance to the market (km) 13.6 6.65 8.3 5.97 1.5 0.51 9 7.03 distance to main road (km) 28.7 5.18 18.9 5.05 27.3 1.51 23.8 6.62 education (years) 6.2 4.21 7.8 3.84 5.4 4.26 6.8 4.14 quantity of fuelwood headloads collected per annum (’00) 2.04 3.14 1.12 4.12 3.09 3.66 1.78 3.77 land under trees (acres) 1.1 1.38 1.4 1.51 1 1.21 1.2 1.42 own mobile phone (1=yes, 0=no) 0.5 0.5 0.6 0.49 0.3 0.49 0.5 0.5 source: authors’ computation, 2013. rences in number of forest benefits known to respondents,distance to the main roadand market and ownership of land. when comparisons were made between different regimes, significantdifferences were observed in farm sizes, distance to the main road, the forest and the market, years of education and land ownership among respondents in the conservancy/reserve regime and those from the kfs regime. significant differences were also observed when the respondents from the community regime and the conservancy regime were compared. these differences were significant in the case of incomes, farm sizes and distances to the market. factors affecting the use of forest products in order to assess the use of forest products by the households, respondents were asked whether they ever extracted products from the forest between june 2010 and july 2011 (figure 4.1). although forests were within the reach of most households (from .01km to 10 km distance) only 51% of the householdssurveyed extracted products from them (olunga, 2013). the mean number of years for formal education was six among those who extracted products and seven years among nonextractors of forest products. the use of the forest products differed among the different regimes. the community regime had the highest percent of extractors of forest products (96%) followed by private (48%) and the kfs regime (38%). the forest products used by the households were fuel wood, charcoal, poles, medicinal herbs and thatching grass (table 4.2). of all the users of forest products, 94% used fuel wood while other products were used by less than 40% of the households. the least extracted product was thatching grass which was used by 5% of the households. in order to examine factors explaining the use of forest products, a binary dependent variable that takes the value of 1 if the respondent extracted a product from the forest and 0 otherwise was used to fit a logit regression model. the results of the fitted regression model are kavoi et al. 237 figure 4.1. use (extraction) of forest products by households (n=77). source: authors’ computation, 2013. table 4.2. types of forest products extracted by households. products extracted number of users percent among product users fuelwood 72 93.5 charcoal 13 16.9 medicinal herbs 14 18.2 poles 27 35.1 grass 4 5.2 source: authors’ computation, 2013. shown in table 4.3. the likelihood ratio (lr) test statistic shows that the model fitted the data well (p-value = 0.0003). the results of this study indicate that the prevailing management regime influences use of forest products (olunga, 2013). results show that belonging in the private/ conservancy regime or kfs regime reduces the likelihood of using forest products other factors constant. the households that are close to the kfs or the conservancy/private forest regime are less likely to use forest products relative to the households in the community regime. these findings show that regime management plays a critical role in determining the decision to use forest products. indeed, the type of management regime determines the scope of monitoring and enforcement of rules. the study findings also reveal that there is a negative and significant relationship between distance to main road and likelihood of using forest products. this suggests that the further the distance to the main road, the less likely the use of forest products. infrastructure is expected to influence the ease of accessing places and facilities such as markets. therefore, if distances to such facilities are large, the likelihood of extracting forest products for sales may be less. the results further showed that the main occupation of the household head influences the use of forest products. the households practising farming as the main occupation were more likely to use the forest products than those whose main occupation was non-farm. in addition, the results showed that income influences the use of forest products. increase in income has positive influence on likelihood of forest product use. this finding is in line with the findings of hedge and enters (2000) that indicated that higher income groups utilize more forest resources than the lower income groups when no forest use restrictions are in place. however, it is in contrast with findings of most past studies (cavendish, 2000; sanders and zeller, 2004; shackleton and shackleton, 2006; wambua, 2008) which suggest that as incomes increase the likelihood of dependence on forests declines. the probable reason for the positive relationship is the lack of alternatives for fuel wood in the study area due to remoteness. households have to cover 238 afr. j. environ. econ. manage. table 4.3factors affecting the use of forest products: logistic regression model. dependent variable (1=use 0=non use) coefficient p-value marginal effects coefficient p-value gender 0.44 0.415 0.08 0.411 natural logarithm of household size 0.05 0.920 0.01 0.920 education (years of formal education) 0.01 0.834 0.00 0.834 natural logarithm of distance to forest 0.25 0.218 0.05 0.207 natural logarithm of income 0.09 0.049 b 0.02 0.043 natural log of farm size 0.15 0.708 0.03 0.707 natural log of distance to main road -1.57 0.084 c -0.29 0.075 regime private/ conservancy -4.07 0.000 a -0.46 0.000 kfs -5.16 0.000 a -0.67 0.000 occupation 1.30 0.032 b 0.24 0.022 constant 6.33 0.062 number of observations 150 wald chi2(9) 32.64 prob> chi2 0.0003 pseudo r2 0.2306 log pseudo-likelihood -79.9588 source: authors’ computation, 2013. note: p-value significance level a refers to 1%, b refers to 5% and crefers to 10% table 4.4. determinants of intensity of use of forest products: poisson and negative binomial regression results. dependent variable= quantity of fuelwood headloads collected poisson regression negative binomial regression coefficient p-value coefficient p-value log of age -0.45 0.106 -0.11 0.739 gender -0.28 0.152 -0.19 0.325 occupation 0.36 0.132 0.72 0.000 a household size -0.07 0.095 -0.06 0.348 log of income 0.03 0.044 0.05 0.018 b log of farm size 0.20 0.041 0.12 0.198 log of collection frequency 0.58 0.000 0.94 0.000 a log of distance to forest 0.27 0.006 0.25 0.089 c regime conservancy/private -0.20 0.395 -0.48 0.082 c kfs -0.75 0.003 -0.77 0.003 a constant 4.09 0.000 1.38 0.218 number of observations 150 508.58 mean -432.19 0.000 -0.387 wald chi2(10) dispersion log pseudo-likelihood prob> chi2 lnalpha source: authors’ computation, 2013. note: p-value significance level a refers to 1%, b refers to 5% and c refers to 10% kavoi et al. 239 table 4.5. attitude towards forest conservation. percent of households within the response attitudinal views/dimensions strongly disagree disagree neutral agree strongly agree importance of forest conservation 18 46 2 20 14 tree nursery mgt and farm forestry 6 20.7 6 54.7 12.7 methods of fuelwood conservation 5.3 26.7 8.7 50 9.3 honey production techniques 11.3 46 5.3 34 3.3 interaction with forest officers 4 38.7 12.7 36 8.7 community surveillance 7.3 28.7 6 52.7 5.3 consultations on forest related activities 3.3 34 6 45.3 11.3 partnerships with other stakeholders 11.3 36.7 9.3 41.3 1.3 confidence in future user rights 12.7 23.3 18.7 38 7.3 interest in knowledge acquisition 2.7 3.3 4 74.7 15.3 general support for conservation activities 1.3 9.3 8.7 66.7 14 labour and monetary contribution 8 28 10 50.7 3.3 source: authors’ computation, 2013. long distances to get kerosene or cooking gas, making use of firewood more attractive. intensity of use of forestproducts among households the factors that influence the extent to which households use forest products was assessed by estimating both poisson and negative binomial regression models (olunga, 2013). the dependent variable was the quantity of fuel wood collected (measured by the number of headloads). the results of both models are presented in table 4.4. the mean deviance and the pearson chi-square ratio (the pearson chi-square value divided by its degrees of freedom) were used to assess the degree of fit of the poisson model. the estimated deviance and pearson ratios are shown below: deviance/df = 4167.773/141= 29.56 chi-square/df =4382.065/141= 31.08 from these results, both ratios are significantly greater than 1 indicating that there is evidence of overdispersion. hence the poisson model does not fit the data well. consequently the discussion below is based on the results of negative binomial regression model. the likelihood ratio test of the model (nbrm) has a p-value of 0.000 showing that the model fits the data well. as hypothesized the management regime influences the intensity of use of forest products. the relationship between the regimes and the quantity of forest product used is not only negative but also statistically significant. this implies that the expected number of head-loads of fuel wood decreases by 0.48 and 0.77 for the private and the kfs regimes, respectively. the decrease in expected number of head-loads of fuel wood collected is lower in the private regime probably because of challenges of monitoring the expansive borders by an inadequate number of staff. the hypothesis that management regime does not influence the intensity of use of forest products was therefore rejected. results also show that household income influences the level of use of forest products. an increase in household income by ten percent increases the expected number of head loads by 5% holding other model variables constant. this result corroborates that of hedge and enters (2000) who found that the higher income groups utilize more forest resources than the lower income groups when no forest use restrictions are in place. however as in the case of the binary model results, the findings contradicts those of other studies (cavendish, 2000;shackleton and shackleton, 2006 and wambua, 2008) which reveal that as incomes increase the likelihood of dependence on forests declines. table 4.4 also shows that distance to the forest increases the expected number of head loads of fuel wood collected. hence, there is higher use of forest products among households that are further away from the forest edge. if the distance to the forest were to increase by a kilometre, the expected number of headloads would increase by 0.27, holding other factors constant. this finding however contradicts those of other studies on forest products extraction by households (thapa and chapman, 2010 and hedge and enters, 2000). their studies found that the closer households are to the forest the greater the probability of extracting products. fuel wood is a basic need for households and cannot be easily substituted with other sources of energy in remote villages due to distances and costs to access alternatives. thus households are willing to travel as far as it takes to collect fuel wood. another possible reason for going to further distances to collect forest resources is that people in that area may not easily identify the residence of people from far. although the reporting may be done, apprehending the person may not be as easy as a resident whose home is known. the main occupation of the household head also significantly influences the quantity of fuel wood collected. the expected number of head-loads of fuel 240 afr. j. environ. econ. manage. table 4.6. results of exploratory factor analysis. factor and item description factor loading factor 1:education and knowledge on conservation we have been educated on importance of forest conservation .792 we have received training on tree nursery development and farm forests use .808 we have been informed on use of fuel conservation methods to conserve forests .794 we are confident of land-use rights in the long term .639 factor 2:interaction and application of knowledge we have changed our honey production techniques to minimize tree species losses .982 there is consultation regarding forest related activities and forest conservation .981 factor 3:social and economic commitment there is surveillance between community and forest guards regarding forest use .629 there is partnership between the community and other stakeholders on forest conservation .879 am willing to invest my resources in terms of time and finances to protect forest destruction .540 factor 4:personal initiative am interested in knowing more about what to do regarding forest conservation .822 am willing to support conservation practices that will ensure forest protection .826 factor 5:consultation and goal achievement we have interaction with forest guards thus conservation is now achievable .902 source: authors’ computation, 2013. wood collected is higher by 0.72 for households whose main occupation is farming relative to those who have other activities as the main occupation. attitude towards forest conservation in order to assess households’ attitude towards forests conservation, respondents were asked a series of questions that cover different aspects relating to forest conservation. these were in likert scale format with the scale ranging from strongly disagree and strongly agree (i.e. on a scale of 1 for strongly disagree to 5 for strongly agree). points were added from each statement and divided by the highest sum to calculate a score in percentage terms. the mean score of all respondents was 54.07±10.30. if a respondent scored above the mean score then they were considered to have a positive attitude based on the stated scale range 1-5 with 5 being strongly agree (positive statement). for purposes of statistical analysis respondents with neutral and negative attitudes were grouped together. the finding wasthat only 10% of the respondents had a positive attitude and 56% were on the borderline. the results of the analysis of responses to the statement are as shown in table 4.5 (olunga, 2013). the results show that 20% of the respondents received some form of education and training on forest conservation and 50% had been educated on fuel wood conservation methods. the communities’ time value for conservation activitieswas low. results also show that 48% of the respondents attended meetings and were enrolled in groups focusing on environmental conservation as also indicated in table 4.1. regarding the stakeholder involvement in forest conservation initiatives and management 41% of the respondents knew about the existence of partnerships between the local communities, the kfs and the ngo’s working with farmers within the area while 53% were aware of existence of forest surveillance in the community. almost one-half (45%) of the respondents indicated that consultations among stakeholders on forest related activities was a positive contributor to forest conservation. however, studies conducted in other countries reveal that, where community members and other stakeholders are involved in environment management, the laid down strategies can be achieved given the local area conditions (rishi, 2007). the respondents’ personal commitment to forest conservation was also considered in the study. majority of respondents (75%) expressed their interest in learning about forests conservation. overall, 67% of the respondents were willing to support efforts to protect the forest and about one-half of the respondents (51%) indi kavoi et al. 241 cated that they would invest their time and finances in conservation efforts. factor analysis was used to identify latent dimensions underlying the different variables that measured respondents’ attitudes. responses to the 12 five-point likert-type scale items were subjected to principal component factor analysis. factor analysis was selected to create measurement scales. in order to develop these scales, exploratory factor analysis with varimax rotation was employed. the objective was to obtain fewer dimensions that reflected the relationships among these inter-related variables. an eigen-value greater than one rule was applied in identifying the number of factors. the variables that had large loadings on the same factors were grouped together. factor loadings value of 0.50 and above is normally considered good and significant. the analysis produced a solution with five factors that accounted for 75.2% of the total explained variance as shown in table 4.6. the kaiser's overall measure of sampling adequacy obtained was 0.68, which borders on the recommended threshold of 0.7 suggesting that the data is marginally appropriate for factor analysis. four attitude variables concerning education and knowledge of conservation were loaded on factor 1 with the cross-correlation coefficients of 0.792, 0.808, 0.794 and 0.639. this factor accounted for 28.7% of the total variance and was termed ‘education and knowledge of conservation’ because these variables involve awareness of conservation practices by local people. higher scores and positive responses on this factor revealed a general need for promoting education on conservation practices. factor 2 had cross-correlation coefficients of 0.982 and 0.981. because these variables imply application of acquired knowledge and interaction among stakeholders, factor 2 was then labeled ‘interaction and knowledge application and accounted for 15.7% of the total variance. three attributes (namely, surveillance, partnership and investment) were loaded on factor 3 with crosscorrelation coefficients of 0.629, 0.879 and 0.540. these attributes focused on social and economic issues. hence factor 3 was termed ‘social and economic commitment’. it accounted for 11.4% of the total variance. factor 4 had cross correlation coefficients of 0.822 and 0.826 and these variables were labeled ‘personal initiative’ and it accounted for 10.8% of the total variance and the fifth factor which represented the achievement of the goal on conservation had a cross correlation coefficient of 0.902. it was termed ‘consultation and goal achievement’ and it accounted for 8.4% of the total variance. the cumulative percent of variance for all the factors explained was 75.2. the findings on the attitude questions show that majority of the respondents had a negative attitude towards conservation (90%). the findings suggest the need for information on conservation; desire to know more (75%); willingness to support conservation activities (66%), and labour and financial contributions (51%). conclusions and recommendations the purpose for this study was to determine the factors influencing the decision to use forest products and the attitudes of farmers on forest conservation. regression techniques were used to examine decision to use and the degree of use of forest products. the logit regression model was used to assess the factors influencing the use of forest products whereas negative binomial model was used to examine the factors affecting the intensity of use of forest products.the studyalso used descriptive analysis and exploratory factor analysis to assess the attitudes of households on conservation.the data used was collected through personal interviews using pretested questionnaires from 150 households in kipini division of tana delta district. the area was purposively selected to represent the three existing regimes (i.e kfs, community and private management systems) that govern forest product utilization. the study found that the factors explaining the use of forest products include household income, distance from the household to the forest, regime and occupation of the households head. the study particularly found that the prevailing management regime had an inverse relationship with the decision to extract products from the forest. the farther a household was from the forest in the kfs or private regime the lower the likelihood of extraction of forest products. the null hypothesis that prevailing management regime does not influence use of forest products was rejected. the study concluded that prevailing management regime have a significant role in determining extraction of forest products. the study further found that occupation of the household head, household income, distance from household to the forest and prevailing regime explain the intensity of use of forest products. specifically, the study found that prevailing management regime had an inverse relationship with the expected number of fuel wood headloads collected by a household in the kfs and the private regimes compared to the community regime. it was concluded that the type of management system used in the conservation of forests affects the level of forest product utilization by the surrounding community. the attitude of the community members towards conservation was mostly negative. this finding was contrary to our expectations. it is probably because as results indicate, most household heads do not have education on importance of forest conservation and also did not regularly attend forest conservation meetings organized by local leaders, ngos and environmental agencies. the distance to the forest edge was found to be a significant contributor to the use of forest products indi 242 afr. j. environ. econ. manage. cating that households that extract forest products come from far and wide. this finding suggests the need for more effective monitoring and control of forest borders. the number of kfs and kws ground staff needs to be increased to effectively deal with illegal utilization of the forest. an alternative approach may include community policing and community forest associations using youths to assist with guarding the forest borders. the majority of households relied on farming as the main occupation which was found to have a significant effect on utilization of forest products. to minimize on the dependence on forests there is need to invest in sensitization and training on commodity value chains which could boost income. secondly, there is need for provision of accessible credit to households for crop intensification. this will ensure that households have increased food supply and also increased crop residue to use as fuel wood instead of relying on the forests allyear-round as well as reducing expansion of agricultural land into forest demarcated areas.the youth and women development enterprise fund created by the government is a positive approach toward development. however the access of these funds is limited in most cases by lack of awareness by households and bureaucracies. diversification of activities that can help generate income in the area would also act as an incentive to reduce reliance on forest products. references aldrich jh, fd nelson (1984). linear probability, logit and probit models. newbury park, 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african journal of environmental economics and management issn 2375-0707 vol. 8 (1), pp. 001-008, january, 2020. available online at www.internationalscholarsjournals.org © international scholars journals author(s) retain the copyright of this article. full length research paper the socio-economic impact of the lake chad resettlement scheme, nigeria e. d. oruonye department of geography, taraba state university, p. m. b. 1167, jalingo, taraba state, nigeria. e-mail: emmyodan@yahoo.uk. tel: 07039271480, 08025250182. accepted 21 october, 2019 this study was undertaken with the objective of assessing the socio-economic impacts that have taken place since the arrival of different batches of settlers following the resettlement scheme. these impacts include damages exerted on the natural environment, accessibility to sites, provision of infrastructural facilities and the overall success/failure of the resettlement programme. the study employed descriptive survey method including both quantitative and qualitative data collecting instruments. the checklist method of impact assessment was employed in this study. the high number of people who indicated that they did not observed any socio-economic impact of the resettlement scheme on the environment is a reflection of the low level of awareness of the people about environmental impacts of such projects. this study recommends the implementation of existing framework of seia in order to ensure that local people and other interests are effectively represented in the process of resettlement scheme. key words: lake chad, impact assessment, socio-economic, scheme and resettlement. introduction the prolonged drought in the sudan sahelian zone of west africa has resulted in the proliferation of permanent, semi-permanent and mobile settlements all over the floors of lake chad (ijere, 1997). increasing aridity has also resulted in herders of different nationalities moving to the lake floor in the dry season for pasture and water. migration to these areas has brought about interaction of people of different nationalities resulting in conflicts. conflict resulting from scramble over diminishing fishing grounds and emerging farmlands are now commonplace. the nigerian chad war of 1983 and current dispute over territory in the lake area between nigeria and chad and between nigeria and cameroon are all fallouts from the drying up of the lake. the current dispute between nigeria and cameroon led to the intervention of the international court of justice (icj) in 2002. the international court of justice (icj) ruling on the boundary dispute between nigeria and cameroon led to the ceding of 33 villages to cameroon in the lake chad region (omipidan, 2005; bolori, 2005) the decision of the federal government to resettle returnees affected by the international court of justice (icj) rulings on the boundary dispute between nigeria and cameroon in some selected communities along the lake chad area, (fragile environment) is bound to have a lasting impact on the environment (physically and socioeconomically). this study examines the socio-economic impact of the resettlement scheme on the fragile environment of the lake chad area of nigeria. the concept of socio-economic impact studies provides a general framework for the assessment of a development project in order to determine its likely ecological and socio-economic consequences and also determine any possible alternative (ibrahim, 1997). socio-economic impact involves analysis of potential impacts of new projects on local communities and wider society, and the development of strategies to manage these impacts. socio-economic impact studies can be carried out as a separate study, but often delivered through an integrated environmental and socio-economic impact studies. socioeconomic impact assessments are usually carried out to assist policy makers in making decisions that promote long-term sustainability, including economic prosperity, a healthy community, and social well-being. a socioeconomic impact examines how a proposed development will change the lives of current and future residents of a community. because socio-economic impact is designed to estimate the effects of a proposed development on a figure 1. map of lake chad basin showing resettlement area. community’s social and economic welfare, the process should rely heavily on involving community members who may be affected by the development. socio-economic impact provides a foundation for assessing the cumulative impacts of a development on community’s social and economic resources. unfortunately, socio-economic impact often takes a back seat to other types of impact assessment such as fiscal and environmental impact analysis because the impacts are often more difficult to measure, and the social impacts associated with a development are generally more subtle than impacts on a community’s fiscal balance sheet or local natural resources (burdge, 1995). this paper examines the socio-economic impact of the resettlement programme and project construction on the immediate environment. specifically, the study investigates how the people living in the host communities and the resettlers perceive the socio-economic impact of the resettlement scheme on the immediate environment. the distribution of the resettlement sites are as follows: dambore and sagir/kirta in ngala lga and ali sherifti in kukawa lga, both in borno state of nigeria (figure 1). materials and methods the effect of large regional project such as the lake chad resettlement scheme deserves environmental impact assessment (eia) yet this was not done either before or during the resettlement process. consequently, there is no previous eia with which thisstudy being carried out about 5 years after the completion of theproject can be compared with. since there were no eia before or during the resettlement process, the views of the people currently living in the resettlement areas were obtained using questionnaires and interview schedule. the checklist method of impact assessment was used in examining some of the changes that the resettlement scheme has made and will still make in the future on the resettlement areas. first, an exhaustive checklist of impacts that such project (resettlement scheme) can have on land and water resources as well as the checklist impacts that the projects or the exercise can have on human life and welfare was compiled. after developing the items in the checklist, they were carefully examined and a manageable number of important impacts were selected for detailed study. the rest of the impacts which could not be measured given our disposition, such as air and noise pollution were discarded, although, their impact could be measured indirectly through the views of the respondents living in the communities. judicious scoping enabled us to limit both the number of impacts, and the depth to which the impact was studied. after the corrections, the following major categories or topics were selected for the checklist of possible impacts of the resettlement scheme on the immediate environment. each category contains a number of relevant items. they are: 1. socio-economic impact of the resettlement on land and water resources (9 items). 2. services provided by the resettlement scheme’s projects (6 items) 3. socio-economic impact of the resettlement projects uses on the environment (6 items). 4. infrastructural facilities attracted to the communities by the resettlement scheme (9 items). this checklist designed on a 5point response continuum scale was based on the likert scale after modification by okoye (1996) as cited in onokala (1997). strong positive impacts are coded 5, positive impact is coded 4, while no impact observed, negative impact observed and strong negative impacts are coded 3, 2 and 1, respectively. the quantification of the impacts enabled the determination of the degree to which each item contributes to the impacts of the resettlement scheme on the environment. the resettlement areas include sagir and dambore in ngala local government area and ali sheriffti in kukawa local government area, both in borno state. sixty-five questionnaires were administered in each of the three resettlement communities previously mentioned and forty four questionnaires in kirta village (nearby village hosting the returnees). in all, 239 questionnaires were administered in the study areas. the administration of the questionnaires was randomly done to ensure that every adult has equal chance of being selected (ibe and oruonye, 1999). the pearson’s product moment correlation coefficient was used to analyze the relationship between the 4 categories of socioeconomic impact of the resettlement scheme on the environment. principal component analysis (pca) was later applied to the data to determine the loading of each of the variable on the component. tables were used in presentation of results. results and discussion the study examines the scores of the respondent on the socio-economic impact of the resettlement scheme project on the environment. these socio-economic impacts are in four categories, namely; category a socio-economic impact of the resettlement scheme on land and water resources is: 1. socio-economic impact on depletion of land for other uses (a1). 2. socio-economic impact on damage to agricultural land (a2). 3. socio-economic impact on damage to existing properties such as houses (a3). 4. socio-economic impact on damage to economic trees (a4). 5. socio-economic impact on destruction of hamlets (a5). 6. socio-economic impact on migration of communities (a6). 7. socio-economic impact on destruction of existing roads (a7). 8. socio-economic impact on pollution of sources of drinking water (a8). 9. socio-economic impact on access to sources of drinking water (a9). category b services provided by the resettlement scheme’s projects (6 items) 1. medical services (b1). 2. education service (provision of teachers) (b2). 3. extension services (b3). 4. security services (b4) 5. increase in volume of trading in the affected areas (b5). 6. increase in volume of traffic (transportation) (b6). category c socio-economic impact of the resettlement projects uses on the environment (6 items) are: 1. solid waste generation in the affected areas, as a result of the project (c1). 2. litter generation by workers and users of the project facilities (c2). 3. air pollution (c3). 4. noise pollution (c4). 5. water coloration (c5) 6. vegetation exploitation for fuel wood uses (c6). category d facilities attracted to the communities by the resettlement scheme (9 items). 1. provision of health facilities (d1). 2. provision of educational facilities (d2). 3. provision of marketing facilities (d3). 4. provision of security (d4). 5. provision of agricultural development facilities (d5). table 1. average percentage of response option. category a (strong b (positive c (no impact d (negative e (strong negative positive impact) impact) observed) impact observed) impact observed) factors resource-i 0.1 10.5 49.7 18.1 21.6 service ii 2.8 96.7 0.5 0.0 0.0 use iii 0.0 0.0 50.0 2.4 47.6 facilities-iv 8.3 69.5 21.0 1.2 0.0 source: fieldwork 2006. table 2. pearson correlation coefficient of the four factors. factors q1-resource q2service q3uses q2service 0.0693 q3uses 0.8990 -0.3340 q4facilities 0.0203 -0.9167 0.4556 source: statistic result. 6. provision of housing (d6). 7. provision of water supply (d7). 8. provision of transport network (d8). 9. provision of mass literacy facilities (d9). the average scores of each respondent/case on the 5point response scale was computed for each category on the checklist, this average score was then entered in the appropriate column of the response option (and is presented in table 1). the socio-economic impact of the resettlement scheme on land and natural resources (category a = resource) and the socio-economic impact of the resettlement project use on the environment (category c = use) have majority of the respondents under no impact observed, negative impact or strong negative impacts. on the other hand, services provided by the resettlement scheme (category b = service) and the facilities attracted to the resettlement areas (category d = facilities) have majority of the respondents under positive, strong positive and no impact observed. under category a, 39.7% of the respondents indicated that the impact of the resettlement scheme on the land and natural resources are either negative (18.1%) or strongly negative (21.6%) while 49.7% of the respondents indicated that no impact was observed. under category b, 2.8% indicated strong positive impact while the remaining 96.7% indicated strong positive impact and 0.5% are for no impact observed with nothing under the other columns. under category c, 50% of the respondents could not determine the impact of the resettlement project use on the environment while 50% of the respondents indicated that the impact of the resettlement project use is either negative (2.4%) or strongly negative (47.6%). category d indicates that facilities attracted to the resettlement areas show positive impact (69.5%) or strongly positive impact (8.3%) and no impact observed (21%) and negative impact observed (1.2%). after calculating the pearson’s product moment correlation coefficients between the 4 categories of socioeconomic impact of the resettlement scheme on the environment (table 2), principal component analysis (pca) was also applied to the data and the results of this analysis are presented in table 3. the result of the correlation of these four categories is shown in table 2. the result shows that there is a very weak relationship between category b (service) and category a (resource), r = 0.0693. there is a strong positive relationship between category a (resource) and category c (use), r = 0.8990, a weak negative relationship between category b (service) and category c (use), r = -0.3340. the result also shows that there is a very weak relationship between category a (resource) and category d (facilities), r = 0.0203. the relationship between category b (service) and category d (facilities) is strong negative, r = -0.9167. the relationship between category c (use) and category d (facilities) is weak, r = 0.4556. hence categories a and c (resource and use) are grouped as factor i, while categories b and d (service and facilities) are grouped as factor ii. table 3 shows the principal component analysis (pca) of the socioeconomic impact of the resettlement scheme on the immediate environment and indicates that there are three major factors, which altogether explains 100% of the variation. factor 1, which loads highly on category a (resource) and category c (uses) explain 60% of the variation. the component-defining variable is category a (resource) and it has the highest loading of 58% on this factor. these two categories had 49.7% for a and 50% for c under the impact could not be deter-mined column of table 1. therefore, factor 1 indicates that the socio-economic impact of the resettlement scheme and project use on the environment could not be determined by majority of the respondents most of whom are returnees who were resettled in the areas (plates 2 and 3). factor ii that loads highly on category b (service) and category d (facilities) explains 40% of the variation, the component defining variable is category b (service) which has the absolute loading of table 3. result of the principal component analysis. factor eigen values percentage of variance cumulative percentage of variance 1 2.32319 58.1 58.1 2 1.59431 39.9 97.9 3 0.08235 2.1 100.0 4 1.441e-04 0.0 100.0 source: statistic result. plate 1. nature of ali sheriffti before the resettlement scheme. 39.9% on this factor. the pattern of distribution of these scores on the 5-point likert scale, show that majority of the respondents are convinced of the obvious advantages of the services provided by the resettlement scheme (service) and the facilities attracted to the resettlement areas (facilities). therefore, factor ii reflect the socio-economic benefit and factor i, the socioeconomic cost of the resettlement scheme on the immediate environment. these results of the analysis are further discussed following the socio-economic impact of the resettlement scheme on land and water resources in (category a = resources) and the socio-economic impact of the infrastructural project use on the environment (category c = use) have negative impacts. on the other hand, services provided by the resettlement scheme (b = service) and the facilities attracted to the resettlement sites (d = facilities) have majority of the respondents under the strong positive impact or positive impact. the implications of these are now discussed in details starting with the negative impact. under category a = resources, one item access to source of drinking water (a9) has the highest mean value of 3.7 (table 4). this is explained by the fact that resettlement exercise involves the drilling of boreholes and cement wells to supply water to the people (plate 1) and as such they see the resettlement as having a positive impact on the environment rather than negative. this is followed by the pollution of source of drinking water (a8), destruction of hamlet (a5), damage to economic trees (a4) and damage to existing properties such as house (a3), which have mean values of 2.97, 2.96 and 2.91 respectively, showing no impact observed. destruction of existing access roads and footpaths (a7), effects on migration (a6), depletion of land for other uses (a1) and damage to agricultural land (a2) all have negative impacts or strong negative impacts (mean values between 2.3, 2.143 and 1.143). the people plate 2. dambore resettlement camp. plate 3. ali sheriffti camp showing planted trees. believed that the resettlement exercise have had negative impact on migration because many of the returnees could not cope with the situation on ground and as such have to migrate in search of better fishing grounds or farming areas. they also believed that the resettlement exercise have strong negative impact on damage to agricultural lands and depletion of land for other uses because many of them lost their land to the construction work and others (especially the returnees) could not even have access to land to build house or cultivate. under category c = use, most of the respondents (50%) could not observe the socio-economic impact of table 4. mean distribution of respondent response. category impact type mean of respondent response resources a a (1) 1.14 a (2) 1.14 a (3) 2.91 a (4) 2.91 a (5) 2.96 a (6) 2.14 a (7) 2.30 a (8) 2.97 a (9) 3.70 services b b (1) 4.50 b (2) 4.81 b (3) 3.99 b (4) 3.80 b (5) 3.90 b (6) 3.43 project uses c c (1) 1.04 c (2) 1.11 c (3) 2.99 c (4) 3.0 c (5) 2.99 c (6) 2.99 facilities – (d) d (1) 5.00 d (2) 4.68 d (3) 4.38 d (4) 3.36 d (5) 2.98 d (6) 3.28 d (7) 4.89 d (8) 3.43 d (9) 4.36 the resettlement scheme project use on the environment and for all the items on this category positive impact is non existent. evidence of noise pollution (c4), water pollution (coloration) (c5) and air pollution (c3) from the projects with means of 3.0 and 2.986 show strong emphasis on no impact observed which reflect the nonexistence of pollution resulting from the resettlement scheme. solid wastes from the various projects (c1), litter from workers and users of the projects (c2) and pressure on vegetation (c6) with the least means of 1.043, 1.114 and 1.0, show strong negative impacts on the environment. therefore the mean value of 2.024 (with a standard deviation of 1.0649 and variance of 1.1339) places the socio-economic impact of the resettlement scheme project use on the environment (category c = use) as negative. services provided by the resettlement scheme (category b = service) is seen as positive by over 96% of the respondent and strongly positive by 3.4% and no impact observed by 0.5% of the remaining respondents. it has no score at all on the two other columns. all the items each have a mean value of 3.986 to 4.114. therefore all the respondents acknowledge the over-whelming positive impact of the services provided by the resettlement scheme (medical services, adequacy of teachers, extension services, security services, increase in volume of trading in the affected areas, transport service). facilities attracted to the resettlement areas (category d = facilities) also indicate fairly positive impact on the environment. the mean value for all the items in this category ranges from 2.87 to 4.57. the strong positive impact (8.25%) and positive impact (69.5%) are explained by the fact that all the respondents could easily experience or observe this. generally, the resettlement scheme attracted many facilities, which are by far, better than some of the ones in the local government headquarter (especially the well equipped modern health centers). others include a modern primary and secondary schools with standard classrooms, hostels and staff quarters, an agricultural development center, boreholes with overhead tanks, viewing centers, police outpost and immigration office with quarters. conclusion this study has investigated the socio-economic impact of the resettlement scheme project construction and its uses on the immediate environment. the study shows that very little attention has been devoted to the degree of involvement and participation of the returnees and the host communities compared with the comparative focus upon physical infrastructures. the findings from the study also show that even though infrastructures such as schools, health centres, market stores, viewing centres and boreholes were provided in each of the resettlement sites, they were not the immediate needs of the resettled people. the resettled people would have preferred a canal on the lake chad to enhance their means of livelihood and transportation, shelter to accommodate them and land for farming. the resettlement therefore has increased pressure on the already fragile environment of the lake chad region. thus, contrary to the expected benefits, enhanced income, higher standard of living, increased employment opportunities through general enhancement of farmers and fishermen’s welfare by way of government support, most of the returnees have experienced the worst hardships in their life resulting from poor land fertility, displacement, deception and land deprivation. recommendation this study recommends the need to implement existing framework of seia in order to ensure that local and other interests are effectively represented in the process. also there should be a monitoring body which could oversee the conduct of seias and or a special environmental tribunal which could have as part of its jurisdiction, the power to investigate and review governmental environmental decision on proposed projects. there is need for an seia framework which incorporates a defined role for the members of the public, so that their views and opinions are considered by the decision making agency and further strengthened by the provision of a monitoring body or tribunal. references bolori s (2005). aspects of the political challenges of the lake chad basin commission. al-mahram j. trans-saharan studies. 1&2(1):29-49. burdge rj (1995). a community guide to social impact assessment. university of illinois: urbana. p. 235. ibe ba, oruonye ed (1999). effectiveness of the agricultural development programme (adp) on the quality of life of the people in the rural areas. sahel analyst. 4(1):47-59. ibrahim a (1997). law and policy for environmental protection and sustainable development in nigeria with special reference to water resource development project. unpublished ph.d. thesis, department of law, university of london. ijere ja (1997). man-water relationships: the case of lake chad. pp. 191-198. in. daura,m.m. (1997)(ed.) issues in environmental monitoring in nigeria. nigerian geographical assoc. maiduguri. okoye ro (1996). psychometric properties of likert type attitude scale under varying positions and score values of neutral response. unpublished ph.d. thesis, department of education, university of nigeria, nsukka. omipidan i (2005) echoes of lake chad ceding. daily sun newspaper (lagos, nigeria), 9 th feb., p.16. onokala pc (1997). impact of the enugu-onitsha express way in southeastern nigeria on the socio-economic aspects of its immediate environment. in daura m.m. (ed.) issues in environmental monitoring in nigeria. nigerian geographical association, pp. 203-209. 1 in ternationa l scholars journa ls african journal of environmental economics and management issn 2375-0707 vol. 9 (3), pp. 001-007, march, 2021. available online at www.internationalscholarsjournals.org © international scholars journals author(s) retain the copyright of this article. full length research paper molecular diversity analysis of planctomycetelike bacteria in inosine fermentation and municipal wastewater treatment systems hao zhang, ying xu, yifeng ding, qingxiang yang*, siwei ren, xueling li, xuanyu chen, yuanyuan xu and hongxin hao college of life sciences, henan normal university, xinxiang 453007, china. accepted 11 september, 2020 in this study, the diversity of planctomycete-like bacteria in an inosine fermentation and a municipal wastewater treatment plants was investigated by denaturing gradient gel electrophoresis (dgge) of nested polymerase chain reaction (nested pcr) amplified 16s rrna gene fragments using planctomycete-specific forward primer and a bacteria universal reverse primer. the bacterial community structures in the two wastewater treatment systems were obviously different due to the different treatment processes and different wastewater characteristics. the highest similarity of the microbial community structure happened in the two samples from the acidification and the anaerobic tank in inosine fermentation plant reaching 67%. while the two samples from the anaerobic and the aerobic tank of municipal wastewater treatment plant reached 66%. ten sequences were recovered from the dgge gel and were assigned to clostridia, proteobacteria, bacteroidete and candidate division based on the phylogenetic analysis. the two sequences grouped into candidate division had more than 92% similarities with the planctomycete-like bacterial clones. however, no anaerobic ammonium oxidation (anammox) activities were detected in the samples of these two wastewater treatment plants. key words: planctomycete-like bacteria, wastewater treatment, denaturing gradient gel electrophoresis (dgge). introduction planctomycetales is a separate division in domain bacteria with special characteristics of cell structure, genetics and physiology, etc. researches on the *corresponding author. e-mail: yangqx66@163.com. tel/fax: +86-373-332-5528. abbreviations: dgge, denaturing gradient gel electrophoresis; pcr, polymerase chain reaction; anammox, anaerobic ammonium oxidation; plant if, inosine fermentation wastewater treatment plant; plant m, municipal wastewater treatment plant; abr, anaerobic baffled reactor; ubf, upflow blanket filter; cass, cyclic activated sludge system; hrt, hydraulic retention time; a/o, anoxic-aerobic; cod, chemical oxygen demand; tn, total nitrogen; tp, total phosphate; ss, suspended solid substances. molecular ecology indicated that this group of bacteria had a wide distribution in nature, such as ocean settlings, fresh water ecosystem, wastewater treatment reactors and soil (jetten et al., 2003; fuerst, 2004; fuerst and sagulenko, 2011). all of them played important roles in the cycle of inorganic or organic substances (jenkins et al., 2002). up to now, only four cultured genera of planctomycetales including planctomyces, pirellula, gemmata and isosphaera have been described clearly and they are all aerobic chemoheterotrophs (ward et al., 2006). however, in recent years, the physiological groups of planctomycetales have been expanded as the research being deepened. members of them include not only chemoorganotrophs and obligate or facultative aerobes but also obligate anaerobes and autotrophs (kulichevskaya et al., 2007; shu and jiao, 2008). especially in 1995, the anaerobic ammonium oxidation 2 (anammox) process was first described in a denitrifying pilot bioreactor in the wastewater treatment plant of gistbrocades (mulder et al., 1995). at present, three uncultured genera of anammox bacteria belonging to a deep branching cluster within the planctomycetales, candidatus brocadia, candidatus kuenenia and candidatus scalindua (kuypers et al., 2003; kuenen and jetten, 2001; schmid et al., 2003), have been paid close attentions by investigators due to their high efficiencies of removing nitrogen from nitrite and ammonium without requiring either organic matter or o2 in wastewater treatment processes (alexandre et al., 2009). but our knowledge on planctomycetales is still limited today. so, investigation of planctomycete-like bacteria in different environments should have great significance due to their abundant metabolic diversity. however, few researches about it were involved in industrial wastewater treatment systems, except chouari (chouari et al., 2003) and innerebner (innerebner et al., 2007). simultaneously, some molecular biological techniques such as polymerase chain reaction-denaturing gradient gel electrophoresis (pcr-dgge), fluorescence in situ hybridization (fish) and cloning of 16s rdna have been developed and widely applied to analyze the genetic diversity of microbial communities in wastewater treatment systems giving much more information of microorganisms than traditional cultivation methods. dgge resolves the differences of pcr-amplified regions of genes based on differences in nucleotide sequences (lyautey et al., 2005) and the band patterns from dgge map can directly reflect the genetic diversity of the microbes in certain samples (sanz and köchling, 2007). so, it has been widely used in molecular microbial ecology researches. to increase the sensitivity of such ecological analysis, the technique of nested pcr was developed to assess the diversity of the microbial species presence in low concentrations in environments (liu et al., 2007). in this study, a municipal and a typical inosine fermentation wastewater treatment plant were selected as cases to investigate the distribution and diversity characteristics of planctomycete-like bacteria in biological treatment systems using nested pcr-dgge technique. materials and methods system characterization an inosine fermentation wastewater treatment plant (plant if) and a municipal wastewater treatment plant (plant m) which locate in xinxiang, henan province, china and have run stably for more than two years were selected as cases in this study. plant if produces 700 tons of high-strength and 1,300 tons of low-strength of effluents every day. its wastewater treatment system is composed of an abr (anaerobic baffled reactor), 4 ubf (upflow blanket filter) reactors and a cass (cyclic activated sludge system) tank treating 2000 m 3 wastewater per day as indicated in figure 1. the high strength of the original wastewater was first fed into an acidification basin and then was distributed into the 4 ubf reactors with hydraulic retention time (hrt) of 53 h. the cass tank receives the treated effluents from the ubf reactors and the original low strength of wastewater. plant m is a typical a/o (anoxic-aerobic) process treating 150, 000 m 3 municipal wastewater per day. analytical methods water and activated sludge samples were collected from different units in the two wastewater treatment systems, immediately transported to the lab and stored at -20°c before the chemical and biological analysis (< 48 h). cod (chemical oxygen demand), nh4 + n, total nitrogen (tn), total phosphate (tp) and suspended solid substances (ss) were detected as the standard methods (apha, 1995). the ph was determined using a digital ph meter. for each plant, the mainly physical and chemical characteristics of wastewater at every biological treatment stage are shown in table 1. dna extraction the activated sludge samples firstly needed to be washed three times using phosphate-buffered saline (130 mm nacl, 7 mm na2hpo4, 3 mm nah2po4, ph 7.0) and then centrifuged at 4°c, 10,000 rpm for 15 min. the genomic dna extraction was conducted using the phenol–chloroform method (bourrain et al., 1999) and then checked by electrophoresis on a 0.8% (w/v) agarose gel. nucleic acids were stored at -20°c. nested polymerase chain reaction (pcr) amplification for planctomycete-like bacteria population analysis of activated sludge samples, a nested pcr technique was used to amplify 16s rrna gene to increase the sensitivity. the first round of pcr was conducted using a planctomycetales-specific forward primer pla46f (5’-ggattaggcatgcaagtc-3’) and a bacteria universal reverse primer 1378r (5’-gggcggwgtgtacaaggc-3’) as described by pynaert et al. (2003) and chouari et al. (2003). the second round of pcr was conducted using the above pcr products as templates and the primers gc-341f (5’-cgccc gccgcgccccgcgcccggcccgccgcccccgcccccctacg ggaggcagcag-3’) and 518r (5’-attaccg cggctgctgg-3’) to amplify the v3 region of 16s rdna as the method of cunliffe (cunliffe and kertesz, 2006). denaturing gradient gel electrophoresis (dgge) analysis the second pcr products were analyzed by dgge using a biorad d-code universal mutation system (bio-rad laboratories, usa). dgge was performed in 10% (w/v) polyacrylamide gels that contained a denaturing gradient of 30 to 60% denaturants. electrophoresis was conducted at 25 v for 25 min, and then changed to a constant voltage of 75 v for 16 h. after electrophoresis, the gel was stained for 15 min in eb solution, then immediately observed and photographed by the gel documentation system. the major bands on the dgge gels were excised and cloned into the pmd 18-t vector for sequencing. the recombinant plasmid dna was then extracted using standard procedures and sequenced by sangon biotech company, limited, shanghai, china. analysis of the bacterial community on the dgge fingerprints was conducted using the quantity-one software package (bio-rad laboratories, usa) according to the manufacturer’s instructions. 3 table 1. main characteristics of wastewater in every treatment stage of plant if and m. treatment system ph a cod a (mg/l) nh4 + -n a (mg/l) tn a (mg/l) tp a (mg/l) ss a (mg/l) plant if high-strength wastewater 4.7 6.5 3765.0 8130.0 111.7 171.1 242.7 336.5 31.8 66.5 2406.0 3220.0 adjusting tank 5.5 6.7 4455.0 8322.0 119.5 217.9 251.0 399.0 42.0 90.8 3810.0 3909.0 hydrolysis acidification tank 7.1 7.5 1530.0 5172.0 178.6 213.5 184.9 430.3 22.9 46.3 6802.0 9098.0 ubf 7.2 7.9 2592.0 5302.50 20.1 54.4 209.6 351.1 26.7 46.9 14376.0 27990.0 low-strength wastewater 6.8 7.7 201.0 666.0 44.9 86.1 21.7 83.2 0.2 0.5 853.0 1130.0 cass 7.4 7.6 85.0 231.0 32.2 58.2 23.6 62.9 0.2 0.5 1989.0 2760.0 effluent 7.4 7.8 35.0 156.0 18.0 47.3 24.4 45.3 0.2 0.4 175.0 284.0 plant m influent 7.2 7.7 133.3 281.0 33.4 64.2 38.2 68.2 2.8 4.0 230.0 405.0 anoxic tank 7.0 7.2 45.0 115.7 22.8 44.4 27.0 53.3 14.5 18.9 5104.0 7098.0 aerobic tank 6.8 7.2 18.5 164.2 13.4 24.9 24.8 35.2 1.4 2.5 5079.0 8344.0 effluent 7.0 7.4 9.8 18.5 22.5 27.1 26.4 36.6 0.2 0.7 15.0 90.0 a maximum-minimum are shown. (a) (b) figure 1. flow charts of the inosine fermentation wastewater treatment system (a) and the municipal wastewater treatment system (b). phylogenetic analysis all the nucleotide sequences were analyzed by conducting a blast search (http://www.ncbi.nlm.nih.gov/blast/). alignments of the 16s rrna genes of the isolates and their closest relatives were conducted using the clustal x1.8 program. phylogenetic trees were constructed by neighbor-joining (nj) method with the jukes-cantor correction in mega 4.1 package. anaerobic batch experiments series of anaerobic batch experiments were carried out to detect the anaerobic ammonium oxidation (anammox) activities of the biomass samples from two wastewater treatment systems in 300 ml serum bottles containing 250 ml of mixed liquor as described by pynaert et al. (2003). results and discussion analysis of the microbial community structures in the two wastewater treatment plants total dna was successful extracted from the activated sludge samples originating from different biological treatment units in the two wastewater treatment systems of plant if and m. the pcr-dgge technique was used 4 figure 2. dgge patterns of nested pcr products using the planctomycete specific forward primer pla-46f and the bacterial universal reverse primer 1378r. samples from the acidification basin(a), anaerobic basin(b), aerobic basin (c) of plant if and the anaerobic basin(d), aerobic basin (e) of plant m. special bands were signed by black letters and arrows. in this study to assess the bacterial community structures as described in materials and methods. the results are shown in figure 2. on the gel used to conduct dgge, various lanes contained different microbial samples collected from the treatment units. bands in different positions in the electrophoresis gel were considered to represent unique species of microorganisms. based on the dgge profile, the diversities of the bacteria in different wastewater treatment samples were significantly different, but they were far lower than that in other reports on wastewater treatment systems (alexandre et al., 2009; liu et al., 2007) due to the planctomycete specific primer being used in the first round of pcr. specifically, the highest diversity of the planctomycete-like bacteria occurred in the sample of the anaerobic unit in plant if with at least 10 bands visible and the lowest one happened in the aerobic unit of this wastewater treatment system with only 5 bands distinguished by naked eyes, which suggested that an anaerobic condition might be helpful for the survival of this group of bacteria. however, the diversity of the two samples from the anaerobic and aerobic units in plant m had no significant difference, which was probably due to the shorter hrt and the returned sludge in the anaerobic tank. similarity analysis on the dgge profile (figure 3) indicated that the five samples formed two main clusters, in which the samples from the acidification and anaerobic tanks of plant if were grouped together sharing the highest identity of 67%, the aerobic (cass tank) sample in plant if clustered together with the two samples in plant m sharing the identity of only 11%. moreover, the aerobic sample in plant if formed a separate branch in the second cluster with 31% identity with the other two samples. it is reasonable for the high identity between the acidification and anaerobic samples of plant if that these two environments possessed similar anoxic and nutrient conditions and suitable for planctomycete-like bacteria survival. however, the activated sludge samples from anoxic tank (lane d) and aerobic tank (lane e) in plant m also shared as high as 66% identity, which could be explained as the relatively shorter hrt in the two tanks and the frequent biomass exchange due to the returned sludge from the settling tank to the anaerobic tank. in the aerobic cass tank in plant if, the high concentration of dissolved oxygen and large amount of low strength of wastewater fed in, which formed a special ecological environment for microorganisms and resulted in lower diversity and identity of planctomycete-like bacteria compared with other basins. finally, the activated sludge in plant if came from plant m at the beginning of the wastewater treatment system being set up, but after two years of adaptation and domestication by the fermentation effluents, the bacterial community structures have largely changed sharing no more than 31% similarity with the original sludge source. taken together, the distribution and diversity of planctomycete-like bacteria in different wastewater treatment system were significantly related to the sewage constituents and the operating factors such as hrt, dissolved oxygen concentration and flow or sludge returning. phylogenetic analysis here we only focused on the bright bands in the dgge profile as indicated in the picture to obtain the information of the dominant planctomycete-like bacterial population in the two wastewater treatment systems. specifically, total 10 bands were excised from the gel and sequenced for further analysis. their sequences have been deposited in the genbank database under the accession numbers of fj950727, fj950729 to fj950736 and fj968106. the 10 sequences were conducted a phylogenetic analysis using software mega 4 and the results are shown in figure 4. based on the phylogenetic tree, the 10 sequences were clustered into 6 different groups including alphaproteobacteria, betaproteobacteria, gammaproteo bacteria,bacteroidetes, clostridia and candidate decision. 5 figure 3. cluster analysis of the dgge profile using the complete linkage method. sequence s4 was assigned to the cluster of alphaproteobacteria. the represented clone was present in the anaerobic basin in plant if and shared 99% identity with an unpublished strain, rhodobacter changlensis which was isolated from oil contaminated soil. clone l1 and t3 were only present and dominant in the aerobic and anaerobic basins of plant m. the represented sequence of l1 was clustered in the group of betaproteobacteria and had 99% identity with an uncultured dechloromonas sp. that was also retrieved from a municipal activated sludge sample (yan et al., 2009). it was suggested that dechloromonas sp. was probably a general bacterial species in the municipal wastewater treatment systems. the represented sequence of t3 was clustered in the group of gammaproteobacteria and had 100% identity with a gammaproteobacterium clone retrieved from waste of a steel plant (freitas et al., 2008). two sequences of s2 and y1 were grouped in bacteroidetes sharing 99 and 100% identities with the two different uncultured clones from a mesophilic anaerobic digester which treated municipal wastewater sludge (riviere et al., 2009). these two clones presented only in plant if and mainly in acidification and anaerobic basins in this study suggesting their predominance in anaerobic conditions. sequence l2, l3 and t1 were clustered into the group of clostridia sharing 97 to 99% identities with some uncultured clones. two sequences, s1 and s3, were clustered into candidate division and shared the maximum similarity of 98 and 100%, respectively, with an uncultured clone from a landfill leachate-polluted aquifer (roling et al., 2001). candidate division is an unclassified group of bacteria in which large amount of possible novel microorganisms are contained and very few pure strains are found till now. further analysis showed that s1 and s3 exhibited more than 92% similarity with the two planctomycete-like bacterial clones (dq393189 and dq393190) obtained from the anaerobic basin of an alcohol plant wastewater treatment system in our previous report, in which the sludge samples showed low anammox activities even under the disadvantage environments for anammox microorganisms. however, the sludge samples in this study had no such activities based on our near one month continuous detection. different from clone s1 only existing in typical anaerobic condition (acidification basin and anaerobic basin of plant if), clone s3 was present in all the samples including aerobic and anaerobic conditions of the two wastewater treatment systems. it suggested that the represented strain of s1 was a strict anaerobe, while that of s3 was a facultative species. taken together, although the brightness of the bands is high enough in the dgge gel, no sequence had enough scores to be assigned to the group of planctomycete-like bacteria based on the blasting results from the website of http://www.ncbi.nlm.nih.gov/blast/. while extensive diversities of bacterial species were found in other order, which was probably resulted from the low specificity of pcr amplification by using planctomycete-specific forward primer and a bacteria universal reverse primer. however, we tried the amplification using the planctomycete specific reverse primer instead of the universal one and no pcr band could be obtained. in our previous amplification of sludge samples from an alcohol fermentation wastewater treatment plant using the same set of primers, although lots of bacterial species in other orders were recovered still 16% planctomycete-like species were obtained. the reasons for this phenomenon may be in two sides. specifically, there was indeed no planctomycete-like bacterium in the inosine fermentation wastewater treatment system, or some species were too weak to be detected by dgge method while they might be detected by picking and sequencing enough quantities 6 figure 4. phylogenetic tree constructed by nj method and showing the affiliations of 16s rrna gene sequences recovered from the wastewater treatment units of plant if and m. of clones. further confirming work is under conduction using the method of 16s rdna cloning and sequencing (figure 4). the distribution and diversity of bacteria in different 7 wastewater treatment system were significantly related to the sewage constituents and the operating factors such as hydraulic retention time, dissolved oxygen concentration and the flow or sludge returning. on the dgge gel conducted by using a planctomycete-like bacterial forward primer and a universal reverse primer, no band was related to planctomycete-like bacteria, while two bright sequences were clustered into the unclassified group of candidate division sharing only 92% identity with the reported planctomycete clones. no anammox activity was detected in the sludge samples from both the wastewater treatment plants. acknowledgements this study was supported by the national natural science foundation of china（nsfc 21077032) and the henan province outstanding youth fund (104100510006). references alexandre sm, caliz j, balaguer md, colprim j, vila x (2009). development of batch-culture 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approaches. water res. 43(1):195-203. in ternationa l scholars journa ls african journal of environmental economics and management issn 2375-0707 vol. 7 (5), pp. 001-007, may, 2019. available online at www.internationalscholarsjournals.org © international scholars journals author(s) retain the copyright of this article. full length research paper creating a soil data base in a reconnaissance soil fertility study of an encroached forest reserve in northern nigeria for a reforestation programme f. o. adekayode1 and d. t. akomolafe2 1 department of crop, soil and pest management, federal university of technology, akure, nigeria. 2 department of computer science, joseph ayo babalola university, ikeji, arakeji, nigeria. accepted 11 january, 2019 the reconnaissance soil fertility study of 10,000 ha partly encroached forest reserve located between latitude 11°47’n and 11°56’n and longitude 4°22’e and 4°32’e in northern nigeria was conducted in 2009 to generate a soil fertility data base of the reserve. the tracking of the forest reserve boundary was done using a garmin 72 model global positioning system (gps) receiver. the geographic coordinates were input into the computer to generate a digital map of the forest reserve. the entire forest reserve was divided into grids to guide in the location for soil sampling using the gps/geographic information system (gis) geospatial technique. soil auger studies were made at 250 locations to site 60 sampling pits to collect soil samples for laboratory analysis of soil properties. forest soils were classified into three groups using soil depth as a limiting parameter in the soil fertility assessment. the soils were sandy clay loam and the ph indicated a moderate to strong acid status with low content of organic matter, percentage nitrogen, available phosphorus, potassium, calcium and magnesium. a reforestation programme with the planting of acacia for soil rehabilitation was recommended for the reserve as the tree stands would serve to protect the land against erosive activity of wind and also serve in enriching the soil with nitrogen. key words: soil fertility assessment, reforestation program, forest reserve, geographic information system. introduction reforestation had aptly been described as the tree planting process undertaken to replenish already harvested trees in existing forest land in order to ameliorate the soil fertility that had been degraded as a result of uncontrolled felling of forest trees (moffat and boswell, 1990; jaiyeoba, 2001; saarsalmi et al., 2010). the need for tree replanting has become desirable as rampant deforestation destabilized the ecosystem and caused increasing green house effects, soil erosion, loss of biodiversity and drastic climatic changes (kassas, 1995; bashir, 2010; putatunda, 2010). it had previously been explained that forests absorb carbon dioxide through their photosynthesis cycle and increasing forests with reforestation and discouraging deforestation would help mitigate global warming (rosillo-calle and hall, 1992; yokoyama, 1997;. *corresponding author. e-mail: adekay98@yahoo.com. several efforts have previously been made as discussed by copperwiki (2010) for successful, sustainable and standardized afforestation and refores-tation management as exemplified by projects executed by the britain’s forestry commission, the jewish national fund on the yatri forest and also the green wall of china which aimed to halt the expansion of the gobi desert. the yatri forest project was a type whereby afforestation project had been successfully executed in harsh desert conditions to prevent further expansion of desert land. the need for maximizing the use of available land resources with high yield tree species had become desirable and achieving this goal greatly depends on climate and soil conditions (ravindranath et al., 2006; wu et al., 2007). the scope of afforestation would extend beyond just planting of trees to planting of the right types of trees at the right places which would require soil fertility investigation to confirm the soil fertility status that would support the particular tree types (moshki and lamersdorf, 2010). soil fertility and management had been found essential to determine the type of forest trees to be planted as tree types influence soil properties (ritter, 2009; sartori et al., 2007). several methods of soil fertility investigation were employed in confirming the fertility status of soils (assefa and glatzel, 2010; belachew and abera, 2010). some of the conventional methods of soil fertility investigation adopted in the past included locating study points randomly, zigzag direction and cutting of traverses at known regular intervals and these methods had not ensured the completion of soil fertility investigation within the specified time frame and the required degree of accuracy. the application of geospatial technology involving the use of global positioning system (gps) and geographic information systems (gis) had greatly improved the old traverse techniques and forest soil fertility studies using remote sensing and gis techniques had been reported (solanke et al., 2005; oza et al., 2006; bhagat, 2009). the previous research in medugu et al. (2010) had confirmed the role of afforestation programme in combating desertification in nigeria and also in the research findings reported by jaiyeoba (2001) in the evaluation of the performance of eucalyptus and pine plantations for soil rehabilitation in nigeria savanna environment. ademoh and abdullahi (2010) in nigeria had discussed the use of acacia species in soil rehabilitation and also in the economic values of production of binding resins products from it. the two species of acacia trees acacia senegal l. and acacia seyal l. were reportedly planted in semi-arid conditions to prevent desert encroachment. acacia is leguminous plant which in addition to enriching the soil with nitrogen also has the economic benefits of being used to produce acacia gum or gum arabic (lupien, 2007). furthermore, acacia trees had been described as a natural shade tree and when planted properly could lower ground temperature and the nitrogen rich leaves when shed at the beginning of the rainy season could check soil erosion while the decomposition of the leaves would improve the fertility status of the soil. the soil fertility studies for reforestation programme in the studied forest reserve was found desirable in order to replant with trees in proportion to the reserve areas where the original forest trees/shrubs had been illegally felled principally for arable crop production and for domestic fire wood use. the objective of the research was to carry out a soil fertility investigation of the encroached forest reserve for acacia tree reforestation programme. materials and methods site description the study site is situated between latitude 11°47’n and 11° 56’n and longitude 4°22’e and 4°32’e, it is a 10,000 ha forest reserve located in kebbi state in northern nigeria as shown in figure 2. the climate is tropical with two distinct seasons of rainy and dry seasons. the annual rainfall varies between 650 and 1000 mm while the mean annual temperature is 26 and 33°c during the rainy and dry season respectively. the soils are aridisols by the united states soil taxonomy classification system. the soil investigation involved preliminary computer analysis, field work and the laboratory analysis. preliminary computer analysis and field work the tracking of the boundary of the forest reserve was carried out with the use of the gps garmin 72 receiver and the data input into the computer to generate a digital map of the forest reserve. the entire forest reserve was divided into grids to guide in the location for soil sampling using the gps/ gis geospatial technique. the points for soil sampling indicated on the digital map were located on the ground with the use of the gps receiver and soil samples taken from the sampling pits for laboratory analysis. collections of soil samples, packing and transportation to laboratory soil samples were collected from the three types of soils categorized according to depth. for soil depth category of 0 to 15 cm (group a soils), samples were taken from surface layer to 15 cm while for soil depth category of 0 to 30 cm (group b soils), samples were taken from surface to 15 cm and 15 to 30 cm and for soil depth category of 0 to 60 cm (group c soils), samples were taken from surface to 15 cm, 15 to 30 cm and 30 to 60 cm. the soil samples were bagged in 350 cc sampling bag, labeled and transported to the laboratory for analysis. laboratory analysis soil samples were air-dried and sieved through 2 mm sieve and analysed following the laboratory procedures of canadian society of soil science (carter, 1993). the particle size distribution was determined by the hydrometer method in which 50 g of sieved air dried soil was weighed into 250 ml beaker and 100 ml of calgon added and allowed to soak for 30 min. it was transferred to a dispersing cup and the suspension stirred for 3 min with mechanical stirrer. the suspension was transferred to a sedimentation cylinder and filled to the mark with distilled water. a plunger was inserted and used to mix the content thoroughly. the stirring was stopped and the time recorded. the hydrometer and thermometer were carefully lowered into the suspension and the readings taken after 40 s. two hours after, another hydrometer and thermometer readings were taken and the hydrometer reading corrected for temperature by adding 0.36 g/l for every 1°c above 20°c and subtracting 0.36 g/l for every 1°c below 20°c. the soil ph was determined in water using a glass electrode ph meter. organic carbon was determined by oxidising soil sample with dichromate solution and later titrated with ferrous sulphate solution (walkley and black, 1934). the total nitrogen was determined using micro-kjeldahl method and the available phosphorus colorimetrically by the molybdenum blue method (bray and kurtz, 1945). the exchangeable cations were extracted by leaching 5 g of soil with 50 ml of ammonium acetate at ph 7. the potassium and sodium in the leachate were determined with a column model 21 flame spectrophotometer while the calcium and magnesium were determined with atomic absorption spectrophotometer. the exchangeable acidity was determined by adding barium chloride buffer solution to soil sample and titrated against 0.1 n hcl. n w e 4°25' 4°30' 4°35' s 11°55' 11°55' 11°50' 11°50' 4°25' 4°30' 4°35' 7 0 7 kilometers scale: 1:150000 figure 1. digital boundary map of the forest reserve. creation of attribute table and link to digital map in creating the attribute table, the soil parameters which included the coordinates specifying the latitudes and longitudes of all the sampling point locations and the soil properties were entered as a table in excel software and saved in a dbase iv (dbf 4) format. the table was automatically linked to the digital map generated from the data and arcview, statistical analysis run to calculate the minimum and maximum values to obtain the average values of soil properties for each of the three soil depth categories of 0 to 15 cm depth (group a soils), 0 to 30 cm depth (group b soils) and 0 to 60 cm depth (group c soils). results table 1 showed the coordinates specifying the latitude and longitude of the forest boundary while figure 1 showed the digital map boundary generated from the coordinates. table 2 showed the coordinates of the sampling pits from which soil samples were taken for laboratory analysis of the physical and chemical properties while figure 2 showed the representations of the 60 sampling pit locations on the digital map. nine sampling pits were 0 to 15 cm depth while 27 and 24 sampling pits were 0 to 30 cm and 0 to 60 cm depth respectively. table 3 showed the mean values of soil properties as generated with arcview statistical analysis. the soil was sandy clay loam with the clay content having an average of 25%. discussion the latitude and longitude readings of the forest reserve boundary in table 1 were taken with the global positioning system receiver which was a satellite linked device that gave the precise locations on the ground. this was used to generate the boundary map of the reserve in figure 1. the principle was used in a previous research of a farm layout which was part of the digital farm map of a crop type museum (adekayode et al., 2007). the coordinates of the sampling pits as shown in table 2 and the representation of the points in figure 2 showed the application of gis to obtain accurate location of soil sample points in the forest reserve for the determination of soil properties at different locations. this principle was n 4°25' 4°30' location of forest reserve 11°55' 11°55' % # $ $ $ % $ $ map of nigeria $ $ % % # ## # $ # # $ $ # % % % % % $ % $ $ % % $ % $ $ % $ % $ $ 11°50' 11°50' % % $ $ % $ legend $ % $ sampling pits $ of 0 to 60 cm depth % % % % $ # sampling pits $ # % $ of 0 to 30 cm depth # sampling pits of 0 to 15 cm depth 4°25' 4°30' 6 0 6 kilometers scale: 1:100000 figure 2. map of the forest reserve showing locations of sampling pits with map of nigeria and location of forest reserve in the inset. table 1. the coordinates of the forest boundary. boundary points latitude longitude boundary points latitude longitude 1 11.872391 4.403176 12 11.806707 4.485918 2 11.864977 4.406828 13 11.855968 4.529515 3 11.842722 4.418315 14 11.915204 4.528312 4 11.841300 4.418831 15 11.909216 4.508716 5 11.832878 4.421458 16 11.901658 4.488075 6 11.824518 4.424462 17 11.895715 4.471336 7 11.816641 4.428395 18 11.887013 4.445890 8 11.807432 4.432798 19 11.881212 4.429336 9 11.803468 4.433649 20 11.877390 4.418026 10 11.805174 4.443000 21 11.874895 4.410660 11 11.804927 4.466656 22 11.872391 4.403176 table 2. the coordinates of the sampling pit locations. sampling pit sampling pit sampling pit (0-15 cm latitude longitude (0-30 cm latitude longitude (0-60 cm latitude longitude depth) depth depth) 1 11.872000 4.404000 1 11.870000 4.410000 1 11.870000 4.510000 2 11.871000 4.405000 2 11.880000 4.430000 2 11.910000 4.520000 3 11.872700 4.408700 3 11.860000 4.440000 3 11.880000 4.460000 4 11.870000 4.405000 4 11.840000 4.480000 4 11.870000 4.440000 5 11.873730 4.409190 5 11.870000 4.490000 5 11.850000 4.420000 6 11.868800 4.416480 6 11.890000 4.510000 6 11.830000 4.430000 7 11.869490 4.411540 7 11.870000 4.470000 7 11.820000 4.450000 8 11.806000 4.468000 8 11.860000 4.460000 8 11.860000 4.450000 9 11.809000 4.469700 9 11.890000 4.470000 9 11.850000 4.490000 10 11.850000 4.440000 10 11.840000 4.480000 11 11.840000 4.430000 11 11.840000 4.450000 12 11.830000 4.440000 12 11.870000 4.410000 13 11.820000 4.440000 13 11.860000 4.530000 14 11.830000 4.500000 14 11.890000 4.520000 15 11.860000 4.480000 15 11.830000 4.470000 16 11.830000 4.460000 16 11.830000 4.420000 17 11.820000 4.480000 17 11.880000 4.440000 18 11.840000 4.454500 18 11.860000 4.430000 19 11.841700 4.454880 19 11.870000 4.440000 20 11.842670 4.454890 20 11.810000 4.480000 21 11.892410 4.488310 21 11.810000 4.470000 22 11.888870 4.448857 22 11.810000 4.450000 23 11.886470 4.488570 23 11.810000 4.430000 24 11.884910 4.489300 24 11.870000 4.450000 25 11.805140 4.468730 26 11.805250 4.434620 27 11.806690 4.449270 applied in previous research to map fertility levels across a farm to serve as basis for the application of farm inputs and also for establishing accurate location of yield data for the production of yield maps for yield monitoring (ziadat, 2005; sudhanshu et al., 2009). liaghat and balasundram (2010) had discussed the use of gis in precision farming to produce a production based farming system that was designed to increase long term, site-specific and whole-farm production efficiency, productivity and profitability. song et al. (2009) in a research on the delineation of agricultural management zones using remotely sensed data concluded that remote sensing was a valuable tool for assessing the variation in soil properties and yield in arable fields. hossain (2009) used the geographic information system to develop a site-specific geospatial database in assessing spatial land use/cover changes in a study site in thailand while adekayode (2006 ) used the soil data base on soil physical and chemical properties to generate the soil map of part of owena forest reserve in ondo state nigeria. table 3 shows the mean values of soil physical and chemical properties was the result of arcview statistical analysis of the soil properties entered as field in the attribute table. soil samples from the sixty sampling pits were analyzed for the physical and chemical properties. each soil property was entered as a field to calculate the maximum, minimum and the average values in relation to the various depths of 0 to 15 cm, 0 to 30 cm and 0 to 60 cm. the physical and chemical properties of soils in the forest reserve were similar and the limitation of group 1 soils was the shallow depth being within 15 cm of the surface and this was caused by hard pan just below the surface. such shallow sampling pits were mostly found in the north western part of the study area and this would make mechanical cultivation impracticable. the remaining part of soils in the forest reserve was 30 cm deep or even deeper. the generally low level of cations reflected the low level of organic matter which reflected in the low nutrient level as previous observation had revealed a direct relationship between organic matter and table 3. the mean values of soil physical and chemical properties. soil properties group a soils group b soils group c soils (0 – 15 cm) (0 – 15 cm) (15 – 30 cm) (0 – 15 cm) (15 – 30 cm) (30 – 60 cm) percentage gravel (%) 5.1 6.0 9.8 5.2 5.7 6.2 percentage sand (%) 61 67 59 68 61 61 percentage silt (%) 14 10 12 11 13 12 percentage clay 25 23 29 21 26 27 texture ph 5.1 4.9 4.9 4.8 4.7 4.6 organic matter (%) 0.56 0.90 0.64 1.11 0.93 0.72 available phosphorus (ppm) 3 2.7 2.3 2.6 2.5 2.4 total nitrogen (%) 0.23 0.35 0.15 0.36 0.15 0.12 sodium (cmol/kg) 0.17 0.16 0.20 0.15 0.16 0.11 potassium (cmol/kg) 0.16 0.21 0.15 0.18 0.16 0.08 calcium (cmol/kg) 1.23 1.42 1.40 1.38 1.36 1.25 magnesium (cmol/kg) 0.58 0.68 0.62 0.71 0.66 1.02 vegetation/land-use shrub shrub shrub shrub shrub shrub nutrient availability to plants (takata et al., 2007). the low level of nutrients showed the high degree of encroachment of the forest reserve by people for arable cropping whereas they did not make serious attempt to replenish the soil fertility with the addition of organic and inorganic fertilizers. the response of forest trees to soil nutrient content had been discussed in previous research (liao, 1977; alfaia et al., 2004; john et al., 2007). tang and robson (1993) in investigating the effects of ph on nodulation of lupinus species observed that ph above 6 had a specific effect in the impairment of nodulation in lupins and the lateral roots to be greatly reduced resulting in decreased uptake of iron and phosphorus while ojeniyi and agbede (1980) in investigating the effect of organic matter on the yield of tree crops in different ecological zones of nigeria observed a positive correlation between soil organic matter and girth of gmelina arborea. the nutrient requirement of some forest trees as reported previously in nwoboshi (2000) stated the requirements for g. arborea to be 960 kg/ha nitrogen, 371 kg/ha phosphorus, 2425 kg/ha potassium and 615 kg/ha calcium while the requirements for tectona grandis to be 640 kg/ha nitrogen, 170 kg/ha phosphorus, 719 kg/ha potassium and 199 kg/ha calcium. this corroborated the earlier research findings of akinsanmi and akindele (1995) while adekayode (2005) had previously reported the potentiality of soil to support the growth of species of forest trees to be highly influenced by topography and parent materials. conclusion the assessment of the fertility status of the forest reserve had been based on the soil data base of soil properties created. the soils generally had low fertility but which could be improved with the addition of both organic and inorganic manure and the productivity sustained with the planting of acacia trees. the digital map of the forest reserve generated with gis technique would allow a periodic review of the soil fertility status. references adekayode fo (2005). chemical properties of soil under plantation of teak and gmelina as affected by different soil forming factors. nig. j. for., 34: 7–13. adekayode fo (2006). application of geographic information systems (gis) in mapping soils of owena forest reserve, southwest nigeria. nig. j. soil sci., 16: 35-42. adekayode fo, ojo k, aduloju so (2007). application of geospatial technology in the digital farm layout of a proposed crop type museum. j. res. sci. manage., 5(1): 53–60. ademoh na, abdullahi at (2010). evaluation of the effective baking conditions for grade 3 nigeria acacia species bonded foundry sand cores. res. j. appl. sci. eng. technol., 2(6): 504-507. akinsanmi fa, akindele so (1995). teak productivity in relation to soil conditions: a reassessment of teak plantation in the dry high forest area of southwestern nigeria. nig. j. for., 24(1&2): 7-10. alfaia ss, ribeiro ga, nobre ad, luizao rc, luizao fj (2004). evaluation of soil fertility in small holder agroforestry systems and pastures in western amazonia. agric. ecosyst. environ., 102(3): 409414. assefa b, glatzel g (2010). measuring soil fertility under hagenia abyssinica (bruce) j.f. gmel by the biotest method, int. j. agron., article id 845087, 5p. doi:10.1155/2010/845087.htpp ://www.hindawi.com/journals/ija.cta.html. bashir m (2010). the impact of bush fire and tree felling. http://allafrica.com/stories /201003090554.html. belachew t, abera y (2010). assessment of soil fertility status with depth in wheat growing highlands of southeast ethiopia. world j. agric. sci., 6(5): 525-531. bhagat vs (2009). use of landsat etm+ data for detection of potential areas for afforestation. int. j. rem. sens., 30(10): 2607-2617. bray rh kurtz lt (1945). determination of total organic and available forms of phosphorus in soils. soil sci., 59: 39–45. carter mr (1993). soil sampling and methods of soil analysis. canadian society of soil sci., lewis publishers, london, p. 823. copperwiki (2010). successful afforestation. http://www.copperwiki. org/index.php.su ccessfulafforstation. hossain z, tripathi nk, gallardo wg (2009). land use dynamics in a marine protected area system in lower andaman coast of thailand, 1900-2005. j. coastal res., 25(5): 1082–1095. jaiyeoba ia (2001). soil rehabilitation through afforestation evaluation of the performance of eucalyptus and pine plantations in a nigerian savanna environment. land degrad. dev., 12(2): 183-194. john r, dalling jw, harms ke, yavitt jb, stallard rf mirabello m, hubbell sp, valencia r, navarrete h, vallejo m, foster rb (2007). soil nutrients influence spatial distributions of tropical tree species. proc. natl. acad. sci., united states of america, 104(3): 864-869. kassas m (1995). desertification: a general review. j. arid environ., 30: 115-128. liaghat s, balasundram sk (2010). a review: the role of remote sensing in precision agriculture. am. j. agric. biol. sci., 5(1): 50-55. liao cfh (1977). the effect of nutrient enrichment on nitrogen fixation activity in the bay of quinte, lake ontario. hydrobiol., 56(3): 273-279. lupien jr (2007). acacia gum and sustainable development in africa. afr. j. food, agric. nutr. dev., 7: 5. htpp://www.ajfand. net/issue 16/issue16commentary.htm. medugu ni, rafee majid m, johar f, choji id (2010). 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species in relation to environmental factors in the subtropical rain forest of taiwan. for. ecol. manage., 239: 81-91. yokoyama s (1997). potential land area for reforestation and carbon dioxide mitigation effect through biomass energy conversion. energy convers. manage., 38(1): 569-573. ziadat fm (2005). analysing digital terrain attributes to predict soil attributes for a relatively large area. soil sci. soc. am. j., 69(5): 1590–1599. in ternationa l scholars journa ls african journal of environmental economics and management issn 2375-0707 vol. 7 (3), pp. 001-008, march, 2019. available online at www.internationalscholarsjournals.org © international scholars journals author(s) retain the copyright of this article. full length research paper identification of future environmental challenges in pakistan by 2025 through environment foresight waris ali gabol* and aleem ahmed pakistan technology board, ministry of science and technology, islamabad, pakistan. accepted 15 november, 2018 technology foresight is defined as “the process involved in systematically attempting to look into the longer term future of science, technology, the economy and society with the aim of identifying the areas of strategic research and the emerging generic technologies likely to yield the greatest economic and social benefits.” technology foresight on environment sector was carried out under the supervision of pakistan technology board on the theme “environment 2025: our future, our choices”. social, technological, environmental, economical, political and values (steepv) is an internationally recognized tool for brainstorming used in conducting technology foresight worldwide and was used by environment panel for collection of issues and drivers, opinions, policies and projects for future of environment in pakistan. more than 20 experts participated in the expert panel brainstorming workshops. a diverse panel was formed with representation from r and d organizations, ministry of environment, researchers and professors in universities, ngo and private sector organizations. a consensus was achieved by the panel on top four most important issues in environment sector which include; (a) water (b) loss of biodiversity, (c) solid waste and (d) energy. furthermore, the causes, remedies, policy recommendations and project proposals were identified for each of the four issues. key words: technology foresight, environmental degradation, water as a resource, biodiversity loss, solid waste, energy, panel discussion, steepv, priority areas. introduction and literature review technology foresight involves systematic attempts to look into the longer-term future of science and technology, and their potential impacts on society, with a view to identifying the emerging change factors, and the source areas of scientific research and technological development likely to influence change and yield the greatest economic, environmental and social benefits during the next 10 to 25 years (unido, 2005). the term foresight came to be known in its present form in 1980s, and it is used to describe the future-oriented activities connected with science, technology and innovation. originally, there was no clear difference made between forecasting and foresight (european commission, 2006). the tools used for forecasting are delphi survey method and system analysis and were used in brand corporation and usa defense sector in back 1950s. the companies at that time were mainly interested in forecasting method for business purposes for example, shell *corresponding author. e-mail: waris_gabol@yahoo.com. during 1960s; although, the need for forecasting also increased when oil crisis took place in the 1970s (cuhls and johnston, 2006). in japan the technological development took place in late 1960’s and on-wards (unido, 2005). france and other european countries started the foresight initiatives in the early 1980s. after a decade, sweden, australia and canada experimentally started technology foresight in late 1980s and before 1990s. today the technology foresight has gone far and several countries are engaged in technology foresight exercise that is, uk, usa, australia, sweden, finland, china, india, taiwan, malaysia etc. keeping in view the huge gains achieved through this exercise, the technology foresight project was initiated by pakistan technology board, ministry of science and technology which include the key major areas which are playing vital role for socio-economic development in country, these include; agriculture, energy , education, environment, information and communication technology (ict), industry etc. this paper exclusively focuses on environmental challenges faced by country or will be faced in coming fifteen years. the foresight allows individuals to think/understand ahead and consider, model, create, and respond to, future eventualities. the strategic foresight group india reports on environmental cost of middle east conflicts. it was noticed that ten million barrels of oil were spilt at sea as well as forty-five million in the desert during first gulf war. although kuwait also suffered extreme land degradation with more than twenty percent of trees being lost and perhaps the most dreadful were releases of carbon dioxide from burning of oil fields. moreover the first gulf war also increased the share of carbon dioxide emission about 1.5% globally in 2003 and the share of the countries like as saudi arabia was 1.17% of the world’s carbon emissions, while egypt, israel and jordan share much less than saudi arabia which were noted between 0.5 and 0.7% (strategic foresight group reports on environmental cost of middle east conflicts by gitanjali bakshi, february, 2009). these types of unnatural activities will diminish the planet in near future. the environmental degradation is increasing day by day in different countries, but the most vulnerable countries are group 77 that includes indonesia, china, philippines, columbia and other fifteen countries. pakistan is also in the list of environmental vulnerable countries. the environmental issues and challenges being faced by pakistan include; natural resource degradation, depletion and pollution of renewable fresh water resources, use of pesticides, noise and air pollution, solid waste pollution, soil degradation, desertification, biodiversity loss, improper discharge of industrial waste etc. (islamic republic of pakistan, 2008). pollution due to the ineffective management has emerged as a major environmental concern in pakistan. its natural resources are increasingly under pressure with rapid population growth and environmentally unsustain-able and ineffective practices and its fresh water resources are being fast depleted which has pushed pakistan into the category of water stressed countries. industrial discharges are continually contaminating the country’s best soil and water resources (surface and ground water) and solid waste dumped on low-lying land or burnt in open air generates dust and carcinogenic pollutants with adverse health implications (islamic republic of pakistan, 2008). pakistan also faces other severe environmental issues and challenges caused by natural hazards such as, floods, earthquakes, droughts, and cyclones. pakistan is also in the list of those countries which are damaged by cyclone and flooding. cyclones cause significant damage in the coastal areas as well as destroy standing crops several hundred kilometers inland. additional environment challenges due to climate change are expected to directly impact on pakistan’s economy which results in loss of 6% of gdp (pakistan strategic environmental assessment report, 2006). for coping and devising an effective strategy for upcoming environmental challenges, the environment foresight study has been conducted in pakistan under foresight project for giving some suggestions and recommendation on most important issues. methodology expert panel discussion using steepv expert panel was formed on environment sector which was represented by members from academia, industry, r and d organizations, private sector, ngo’s and civil organizations unido (2005). the panel met for about five times during a period of six months. the members were identified through face to face meetings and co-nomination process. the experts selected were mainly the heads of their respective organizations such as: chief environment, planning commission, director general, ministry of environment, head iucn, islamabad, head undp, energy and environment section, regional manager, pakistan wetlands program, dean faculty of applied and basic sciences, international islamic university, dean biological sciences, quaid-i-azam university, manager technical assistance, asianics, ceo of strengthening participatory organization, islamabad, deputy director, national biosafety center, (pak epa), director, pakistan environmental protection council, chief wild life planning commission. there were about twenty members who were part of the panel, while many experts responded through e-mails. the proceeding of each workshop was shared between all panel members through online groups. the panel assessed the current situation of environment in pakistan and identified key trends and opportunities on the horizon of 10 to 15 years. the standard method of steepv, unido (2005) was used by panel members for the brainstorming sessions to identify a number of issues and drivers, recommendations and key areas of technological intervention. social (1) environment oriented research and development should be promoted. (2) environment conscious society needed. (3) increasing population is a big social factor. (4) literacy rate is a big issue. (5) awareness regarding environment should be created. (6) youth population trend. (7) environment oriented education for youth required. (8) social cohesiveness needed. (9) youth can be a change agent for pakistan. (10) cross sectoral socialization required. technological (1) use of environmental friendly technologies lacking. (2) male dominant technologies. (3) environmental friendly fertilizers. (4) role of media to create awareness. (5) reliance on foreign resources. (6) technology for environment for example gis. (7) youth access to it needs to be ensured. (8) dissemination of knowledge. (9) solutions should be based on logic. economy (1) poverty a big issue. (2) per capita availability. (3) economy of environment. (4) distribution of wealth. (5) incentives for media. environmental (1) controlled pesticides usage. (2) minimum use of pollutants. (3) rural urban shift needs to be considered. (4) district wise study of environment. (5) water issues to be solved. (6) pilot projects should be initiated. (7) environment technology parks and incubation centres required (8) green labeling should be introduced. (9) water pollution (surface /underground). (10) biodiversity destruction/extinctions/deforestation/ecosystem degradation. (11) land use changes/land degradation/ soil pollution. (12) solid waste pollution. (14) population growth. (15) climate change and global warming. (16) introduction of genetic modified organisms (gmo’s). (17) devastation of natural habitats. (18) diminishing natural resources. (19) air pollution. (20) noise pollution. (21) thermal pollution. (22) pesticides pollution. (23) radioactive waste (pollution). (24) industrial pollution. political (1) lack of political will and vision. (2) need to exploit human resources. (3) political choices and awareness regarding environment friendly technologies. (4) enforcement and implementation problems. (5) pemra should be forced to allocate 10% of time for public service messages. (6) green journalists forum should be established. values (1) ethical issues. (2) gender issues. (3) psychological slavery. (4) equity and equality of distribution. (5) religious aspect needs to be considered. (6) mindset needs to be changed. (7) involve media, parents and teachers in creating awareness. (8) message oriented advertisements and environment impact assessment of advertisements required voting for the identification of top environment issues. after the identification of issues and drivers, the next step was to list down the top four issues in environment sector. the top four most important issues highlighted by members were; (1) water (i) resources (ii) pollution (iii) drinking water) 2. loss of biodiversity (a) forestry (b) wildlife (c) rangeland (d) invasive species 3. solid waste (a) industrial (b) urban waste (c) hospital 4 energy (a) residue burning (b) alternative energy resources (c) energy related pollution (d) inefficient use of energy the most important issue was identified as water which was discussed in detail and was further classified into three main categories that is resource, pollution and drinking water (potable water). the expert panel discussed the major challenges in water related issues. it was discussed that water scarcity is becoming a serious issue all around the world and pakistan is no exception. historically, the water crises originated in the middle east and naturally it lead to arm conflict over the resources. the water resources, including fresh and ground water has shrinked fastly and water availability per capita is going to be reduced also (chietigj, 2006). pakistan, india and china have been sharing same water supplies originating from tibetan plateau (figure 1) (yang and du 2004), tibetan china, india, and pakistan’s status has gone near to water-scarce countries list quickly. if we go back into history, we find that in 1951, india’s annual water availability per person was 5,277 m 3 . in the 1990s, it fell to 2,464 m 3 . by 2025, it is projected to fall dangerously close to the 1,000 cubic meters level (vandana, 2002). as for china; its water availability per person was 4,597 in 1950 and 2,427 in the 1990s – slightly above the sufficiency threshold level. however, by 2025, it is assessed that china’s water availability will plummet to 1,818 m 3 , an alarming number for an approximate population of 1.5 billion (charles et al., 2003). finally, pakistan’s water availability per person in 1950 was an amazing 10,590 m 3 per person. however, it fell drastically to 3,962 in the 1990s and is projected to level out at 1,803 by 2025. results and discussion water related issues the expert panel on environment highlighted the causes, remedies, policy recommendations and projects on water, which includes water as a resource (surface, ground and coastal water), water pollution (industrial, municipal, agricultural and mining) and drinking water (depletion etc.) the causes which were identified include; mismanagement, climate change, deforestation, population increase, poverty, lack of political will and vision, enforcement and implementation problem, unequal distribution of wealth, lack of media role in environment awareness among masses, less proportion of literacy rate, lack of youth population trend towards environment, lack of social cohesiveness towards environment, use of environmental friendly technologies figure 1. water supplies originating from tibetan plateau. source: the china –india –pakistan water crisis. prospects for interstate conflict (james f. brennan lieutenant united states navy b.a; wabash college, 1997), lacking, ethical issues, lack of women consciousness in environment related issues, lack of religious aspects towards environment, lack of mindset changes towards sustainable environment, inequitable water distribution and management in irrigation sector, in-efficiency in water distribution (water losses, theft, channeling etc.), droughts, lack of public participation, lack of latest technologies, lack of co-ordination among organization which are already working in water related issues, improper water supply, lack of water recycling and reuse, ground water contamination, excessive ground water harvesting, subsidies in electricity for tube-wells, ground water pumping, industrial demand, mangrove destruction, lack of understanding of coastal waters and coastal ecosystems, bleaching of corals due to climate change impacts, fishing of endangered species such as some sharks, cutting and lopping of mangrove forests, pollution risks from oil pouring in the sea, discharge of untreated waste in water bodies, lack of collection, disposal and management of domestic and industrial waste, excess use of pesticides and agriculture runoff. remedies a number of remedies were listed down for the above mentioned issues which include; construction of reservoirs, water audits and licensing/water pricing, watershed management, forestation because forest play vital role in biological re-charge mechanisms, water recycling, rain water harvesting, through introduction of rain water collection system by using rain water barrels, regular monitoring of water quality, awareness about water conservation with respect to religious and technical aspect, controlled pesticides usage and encouraging the natural organic farming, minimum use of pollutant, rural urban shift needs to be considered, district wise environmental study needs to be conducted to cope these issues, environment technology parks and incubation centers needs to be required, message oriented advertisements on water conservation strategies, political choices and awareness regarding water should be promoted, needs to exploit human resource in water conservation and management, water conscious society needed, water oriented education for youth required, youth can be a change agent for pakistan, use of technology for water management for example g.i.s, introduction of water metering system, make efficient use of residential indoors and out door water by introducing water saver kits, education on water conservation, pakistan standards and quality control authority should develop standard for clothes washer and make ensure implementation throughout the country, zoning of the coastal belt, afforestation of mangrove, control over fishing, reduced oil pouring into sea, implementation of ramsar, convention, minimize waste wherever practicable, use products designed to enable cost effective waste, reuse and recovery material where feasible, use products manufactured with minimal resource, consumption in the first place, use products efficiently and according to best practice, comply with waste legislation, enforcement of the waste management licensing regulations, waste minimization (reduce, re-use and re-cycling), promotion of bio-degradable waste for example replacement of plastic shopping bags, regulation of drinking water use for purposes other than drinking for example car wash with it. policy recommendations and projects an integrated national water policy which encompass surface and ground water, water conservation strategies in selected cities of pakistan based on the use of efficient technologies and other conservation measures to achieve greater water efficiency and increased sustainability within their jurisdiction, installation of water recycling plants in selected cities of pakistan, desalination of the brackish ground water by reverse osmosis, to establish islamabad as a “water conservation conscious city. causes related to loss of biodiversity loss of biodiversity was recognized as the second most important burning issue by the panel which includes forestry, wildlife, rangeland and invasive species. according to the experts, the causes for loss of biodiversity include; deforestation, population growth, desertification, land degradation, exotic species, diseases (for example shisham die back in pakistan), conversion of forests lands, over grazing, trampling, and other livestock grazing impacts on forests (clearly observed in scrub and thorn forests), in-effective management of forests at state and community levels, de-linking social aspects of forestry, hunting, land use changes, lack of planning, lack rule and regulations, lack of awareness, lack of policy implementation, cartagena protocol exists only for living modified organisms. remedies conserving natural forests with ecologically viable management, forests policy and management at national and provincial levels, forests harvesting within allowed scientifically proven incremental limits, re-forestation, and afforestation of degraded and denuded forest lands, controlling and regulating livestock grazing through rotational exclusion of grazing, promoting rainwater harvesting techniques, discouragement of ground water harvesting for irrigation in water stress areas, reclaiming waterlogged and saline lands with the involvement of local communities/private sector; and rehabilitation of degraded. policy recommendations and projects the policy recommendations should encompass the following areas for sustainable range lands, biodiversity, and forestry sectors in pakistan. (a) population planning the population planning agencies in federal, provincial and local governments and ngo’s shall formulate and implement culturally appropriate strategies and action plans of invigorating population planning programmes in critical ecosystems such as the wooded mountain, arid, coastal and estuarine environments. (b) promotion of education in forest areas the education departments in federal, provincial and local governments and ngo’s shall intensify their activities for promoting education particularly female education in and around the forest areas. this will help in curtailing early marriages, reducing child bearing age and complement population planning efforts. (c) reducing firewood, fodder and timber use pressure on forest. in order to reduce the use of firewood, fodder and timber the following steps should be taken for healthy and sustainable environment: (i) all the concerned government agencies and international and national firms shall extend the supply of piped natural gas, lpg, solar energy and micro-hydro power to areas of critical ecosystems, especially the wooded mountains and coastal areas, so as to reduce the use of firewood, fodder and timber, which play an important role in environment rehabilitation. (ii) all agencies which are carrying out research on domestic energy shall be assisted to focus on key priority research so as to reduce the cost and increase the acceptability of substitutes to firewood such as solar energy, bio gas, local coal etc. (iii) planting of multipurpose trees on the farmlands and wasteland shall be encouraged and promoted for use as fire wood, fodder and construction timber. (iv) plantations of multipurpose tree species shall also be promoted on communal wastelands. (v) the import of timber and timber products shall be liberalized in order to reduce timber demand on meager forest resources. (vi) growing of fodder crops on farmlands shall be promoted in order to reduce grazing pressure on the forest and help establishment of natural regeneration. (d) reducing poverty (i) in the poverty alleviation and other development programs high priority shall be given to integrated land use projects for the sustainable rehabilitation of natural resources with the participation of organized local communities. such projects not only provide employment to the rural poor but also increase household income from agriculture and live stock thereby reducing dependence on meager forest resources. (ii) the sustainable utilization of non wood forest products like medicinal plants, mushrooms, honey, gums wild fruits and nuts shall be promoted as income generating activities for the rural poor. (iii) eco tourism shall be promoted in the mountain areas by way of identifying and publicizing the sites for rock climbing, trekking, wildlife spotting/sighting, and photography, trophy hunting and fishing. (iv) federal, provincial and district governments shall create job opportunities through skill development in the mountainous areas of the country. (e) reducing political interference in forestry and wildlife departments: (i) government shall maintain and improve the status of professionals relating to forests, rangelands and wetlands for ensuring the realizations of the goals of this policy. interference of non professionals in their management of the respective natural resources shall be eliminated. (ii) raising of awareness of the general masses about natural resource management and use (iii) ensuring the civil society has a say in natural resource planning and management through the creation of round tables at provincial, regional and district level; and, (iv) creation of independent forestry commissions at provincial level for monitoring and overseeing the affairs of the forestry sector. (f) biodiversity (i) the provincial governments and other administrative units shall be encouraged and assisted in establishing national protected area system covering all types of ecosystems including juniper forest and chulghoza forest of baluchistan and spruce forest in northern areas and some samples of primary forest. (ii) it shall be ensured that at least 12% of land area of all representative ecosystems in pakistan is protected. (iii) such protected areas shall be surrounded by buffer zones and linked by biological corridors where necessary. (iv) overlap between the protected area system and biosphere systems shall be avoided. the local people having rights in any ecologically sensitive area shall be involved in decision-making process of including the area in national protected area system. (v) areas included in national protected area system shall be managed with active participation of the communities. (vi) conservation, sustainable use and farming of wild species shall be given priority in development planning. (vii) appropriate incentive measure shall be provided to improve local livelihoods supporting biodiversity conservation. (viii) the traditional knowledge of the local people shall be documented for protection of intellectual property rights under an improved proprietary rights regime as protected areas system wide management plans shall be drawn up. (ix) conservation of bio diversity shall be integrated in to all sectoral and cross-sectoral national and provincial, level strategies. (x) the federal government shall provide financial, technical and operating support to the provincial wildlife departments in conservation efforts and implementation of inter national treaties and conventions ratified by the government of pakistan. (xi) the approach of collaborative management and trophy hunting shall be extended to other areas. (xii) the capacity of the department staff and communities shall be built in different disciplines of wildlife management. (xiii) measures shall be taken for the captive breeding of wildlife, particularly the endangered species. (xiv) to ensure proper conservation uniformity shall be brought in wildlife laws and rules presently in vogue in different provinces and administrative units. (xv) check posts shall be established at all airports and seaports to check the illegal trade of wild animals, birds and their products. (xvi) it shall be made obligatory for the custom staff at airports and seaports not to allow trade in wildlife species and their body parts with out valid documents from the competent, governments. (xvii) all the wetlands falling in forest and grasslands shall be conserved in accordance with the obligation of ramsar convention on wet lands of international importance. (g) semi-arid and arid range lands (i) the government and civil society institutions shall undertake a sustained awareness raising campaign about the importance of rangelands. (ii) the government of pakistan shall provide financial assistance for rehabilitation and sustainable management of these ranges – a part of the poverty alleviation funds in the districts will be dedicated for this purpose. iii) range management and rehabilitation plans shall be developed and implemented through community participation. (iv) proper incentive measures including assured tenurial and usufruct rights, legal reforms and financial mechanisms would be designed to compensate the pastoral communities for restoring and maintaining the ecological health of the range lands. (v) the local governments shall develop effective periodic closures of rangelands to rehabilitate them and ensure sustainable livelihood to range dwellers. (vi) integrated development projects shall be initiated in these areas with focus on restoration of community based management systems. vii) alternate approaches shall be tried for rehabilitation and sustainable management of rangelands. (viii) planting of multipurpose tree species shall be encouraged in order to meet the local needs of fodder, firewood and timber. h) sub alpine and alpine pastures (i) the restoration and sustainable management of these pastures shall get priority in development planning. (ii) the restoration process shall be executed through grazer’s participation. (iii) the awareness level of the grazers shall be raised and their capacities built in sustainable management approaches and techniques. (iv) rotational grazing shall be introduced for restoring the health of the pastures. (v) suitable fodder tree species shall be planted on the boundaries and along the ravine for increasing the fodder supply. (vi) where soil erosion is taking place, suitable soil conservation measures shall be adopted. (viii) in depleted pastures, ecological balance of species will be restored to enhance the fodder and nutritious value of the pastures. (ix) corridors will be identified and secured for the passage of the migratory livestock through the natural forests in transit to the pastures, especially where security of regeneration of a forest(s) may so warrant. the panellist emphasized launch of the following projects in biodiversity sector of pakistan: (1) aggressive afforestation and reforestation programmes with plantation suited to the looming climate change. (2) biological control of forest pests by maintaining viable populations of predatory birds and insects through restricted use of chemical insecticide. (3) preservation of rangelands through increase of grasslands using appropriate varieties of grass in saline and waterlogged zones to prevent their degradation. (4) assisting genetically impoverished species or those that have important ecosystem functions by providing natural migration corridors as well as assisted migration. (5) use of gene banks, seed banks, zoos and botanical gardens for preserving genetic diversity and conserving species. issues related to solid waste and energy other issues such as solid waste and energy were also discussed by panel; they highlighted that solid waste and energy problem is also creating alarming condition in pakistan. the sectors contributing in solid waste and energy identified by expert panel were industrial, urban, and hospital waste while in terms of energy residue burning, alternative energy resource , energy related pollution , and inefficient use of energy were identified. they found that in present situation water and biodiversity both are very critical and in coming fifteen years their condition will become more worsening than present. moreover, the biodiversity sector can also help to overcome the energy crises. therefore, experts focused and stressed on water and biodiversity related issues for creating sustainable economy in pakistan. conclusion from the environment foresight, pakistan faces some serious challenges on the horizon. amongst which water and loss of biodiversity are the most significant. the panel agreed to the fact that pakistan will become a water scarce country if urgent steps are not taken to tackle the issue and already it is considered amongst the most water-scarce countries in the world. per capita availability of water has reduced significantly over the years. a large number of population does not have access to clean drinking water with more than 90% of water being consumed for our agriculture. in addition to water, other issues such as loss of biodiversity, solid waste and energy were considered to be major challenging areas for pakistan on the horizon of next ten to fifteen years and a collaborative and a coordinated approach on part of all stakeholders will be needed to overcome these issues in an effective manner. references charles wolf jr., yeh kc, benjamin z, nicholas e, sung-ho l (2003). fault lines in china’s economic terrain, (santa monica, ca: rand) . chietigj b (2006). power and interest news report,” asia’s coming water wars,” 22 august, http://www.pinr.com/report.php?ac=view_report&report_id=545&lang uage_id=1 (accessed 25 october, 2007).vandana s (2007). water wars: privatization, pollution and profit (cambridge, ma: south end press, 2002); brahma chellaney. “averting water wars in asia the next struggle,” 27 june. cuhls k, johnston r (2006). corporate fta (future–oriented technology analysis). anchor paper for the international fta seminar, serville, september 2006 http://forera.jrc.es/fta/anchor.htm. european commission (2006b). using foresight to improve the sciencepolicy relationship. final report “improving the science/policy relationship with the help of foresight project.” project prepared for the ec dg research, unit rtd-k.2 science and technology foresight. march 2006. eur 21967 ftp://ftp.cordis .europa. eu/pub/forsight/docs/ntw_using_report _en.pdf (last accessed 16 april, 2008). islamic republic of pakistan (2008). country environment analysis asian development bank report, dec. pakistan strategic environmental assessment report (2006). vol. 1, aug. 21. strategic foresight group (2009). reports on environmental cost of middle east conflicts by gitanjali bakshi, feb. unido (2005). unido technology foresight manual volume 1, (organizations and methods volume 2 (technology foresight in action). united nations industrial development organization, vienna. http:// www.unido.org/doc/45321. vandana s (2002). water wars: privatization, pollution and profit (cambridge, ma: south end press. yang q, du z (2004). tibetan geography (beijing: china intercontinental press. in ternationa l scholars journa ls african journal of environmental economics and management issn 2375-0707 vol. 7 (4), pp. 001-009, april, 2019. available online at www.internationalscholarsjournals.org © international scholars journals author(s) retain the copyright of this article. full length research paper seasonal variations of physico-chemical properties of the great vedaranyam swamp, point calimere wildlife sanctuary, south-east coast of india ramalingam manikannan1*, subramanian asokan1 and abdul hameed mohamed samsoor ali2 1 department of zoology and wildlife biology, a.v.c. college (autonomous), mannampandal 609305, mayiladuthurai, tamil nadu, india. 2 new # 12, old # 3/10, new street, kollapuram 609608, tiruvarur district, tamil nadu, india. accepted 21 august, 2018 the present study was attempted on the physico-chemical variability of the great vedaranyam swamp of the point calimere wildlife sanctuary, south-east coast of india. seasonal variation study was carried out to examine level of varying physico-chemical parameters such as temperature, salinity, ph, dissolved oxygen, nitrate, nitrite, electrical conductivity, phosphate, turbidity, total dissolved solids and water depth. the physico-chemical parameters have exhibited considerable seasonal and spatial variations. the qualitative study revealed the present status of the physico-chemical parameters, which would be very helpful for policy makers to take precautionary measures to save the swamp. key words: seasonal variations, physico-chemical parameters, point calimere wildlife sanctuary, ph, salinity, temperature. introduction aquatic bionetwork plays vital component on the earth since the origin of life. in addition to drinking, water is used for food production of all means that is agriculture, aquaculture, and animal farming. the quality of water in any ecosystem provides significant information about the available resources for supporting life in that ecosystem. good quality of water resources depends on a large number of physicochemical parameters, the magnitude and source of any pollution load; and to assess that, monitoring of these parameters is essential. researches are being carried out till present (mishra et al., 1993; satpathy, 1996; das et al., 1997; padma and periakali, 1999; govindasamy et al., 2000; rajesh et al., 2002; jayaraman et al., 2003; sharma and gupta, 2004; rajasekar et al., 2005; sridhar et al., 2006; anilakumary et al., 2007; prabu et al., 2008; raja et al., 2008; pradhan et al., 2009; srivastava et al., 2009; damotharan et al., 2010; prasanna and ranjan, 2010). these include seasonal variations in the physico-chemical characteristics and nutrient dynamics in the network of *corresponding author. email: manikannanr@yahoo.co.in. water bodies found across the country. these works also include various types of water bodies like ponds, rivers, lakes, estuaries and reservoirs. however, very little information is available in relation to physico-chemical characteristics of water in the point calimere wildlife sanctuary. hence, the present study was conducted to study the physico-chemical properties of water in the great vedaranyam swamp of the point calimere wildlife sanctuary, india for a period of october 2007 to march 2010. materials and methods the point calimere is located along the coramandal coast, nagapattinam district (10°18’ n, 79°51’ e) of tamil nadu, india; it is bounded by a part of the bay of bengal towards the northeast and palk strait on the south-west embracing a vast swamp area called great vedaranyam swamp. the great vedaranyam swamp is famous for migratory waterfowl’s viz., flamingos, waders, ducks, gulls and terns. the entire swamp belt is about 30 km long and 9 km wide. the swamp represents a mixed ecosystem, influenced by both fresh water and seawater. two industrial salt companies chemplast (chemical and plastics limited) and dcw (dharangadhra chemical works) and a number of small and large salt units that produce edible salt and industrial salt operate in this figure 1. monthly variations of water temperature in different stations during the study period. area. the point calimere wildlife sanctuary was declared as a ramsar site on 19th august, 2002. the swamp water samples were collected from five locations (in 3 different stations) selected in the immediate fsurroundings of the area covered by swamp water. the samples were collected in from 10 to 11am. one composite sample from each site was collected per month during the period of study. physico-chemical properties such as water temperature, dissolved oxygen, electrical conductivity, nitrate, nitrite, ph, phosphate, salinity, total dissolved solids, turbidity and water depth of swamp water were determined following standard methods given by welch (1952), trivedy and goel (1984), wetzel and likens (1991) and apha (2005). rainfall data were obtained from the meteorological unit (government of india) located at vedaranyam. results temperature water temperature was recorded more or less similar in all the stations and differs during seasons (figure 1). water temperature during the sampling of different seasons was found to vary from 20. 6 to 34.0ºc. the maximum temperature was observed during summer (january to march) and minimum was recorded during monsoon (october to december). salinity water salinity varied between 8.0 and 61.0 ppt (figure 2). the maximum salinity was recorded during the month of may (summer) and the minimum was observed during the month of december (monsoon). the station wise variations of salinity maximum in station 3 and the minimum in station. ph water ph was recorded more or less similar in all the stations as well as seasons (figure 3). the ph for the water samples varied between 7.0 and 9.8 and these values ranged from a minimum average in october to december (monsoon) to a maximum average in april to june (summer). dissolved oxygen the dissolved oxygen content was showed more or less similar in all seasons except monsoon, it is high (figure 4). the dissolved oxygen content varied from 5.00 to 9.11 ml/l. the seasonal variation of the dissolved oxygen content maximum observed during november to december (monsoon) and the minimum during april to may (summer). the station wise variations of do maximum in station 3 and the minimum in station 1. electrical conductivity the ec was showed very narrow changes in all stations as well as seasons. the ec values varied between 344 and 888 mho/cm. the maximum value was recorded in station 3 and the minimum in station 1. the seasonal variation of the ec values was showed higher during summer season and lower during monsoon season (figure 5). figure 2. monthly variations of salinity in different stations during the study period. figure 3. monthly variations of ph in different stations during the study period. nitrate the nitrate content was fluctuated between the stations as well as the seasons (figure 6). the nitrate values varied from 0.11 to 0.90 mg/l. the maximum value was observed in station 3 and the minimum in station 1. the seasonal variations of nitrate values were recorded maximum during monsoon / post-monsoon and minimum during summer season. nitrite nitrite was recorded more or less similar in all the stations and seasons (figure 7). nitrite contents fluctuated between 0.01 and 0.06 mg/l. the maximum nitrates was observed during monsoon (october to december) and minimum was recorded during summer (january to march). phosphate the phosphate was fluctuated between the stations as well as the seasons (figure 8). the phosphate values varied from 0.01 to 0.24 mg/l. the maximum value was observed in station 2 and the minimum in station 3. the seasonal variations of phosphate values were recorded maximum during monsoon / pre-monsoon and minimum during summer season. figure 4. monthly variations of dissolved oxygen in different stations during the study period. figure 5. monthly variations of electrical conductivity in different stations during the study period. total dissolved solids the tds varied between 236.0 and 503 mg/l (figure 9). the maximum tds was recorded during the month of november to december (monsoon) and the minimum was observed during the month of may to june (summer). the station wise variations of salinity maximum in station 2 and the minimum in station 3. turbidity the turbidity varied from 3.0 to 18.0 ntu (figure 10). the seasonal variation of the turbidity maximum observed during monsoon and the minimum during summer. the station wise variations of turbidity maximum in station 1 and the minimum in station 3. water depth the water depth was showed very narrow changes in all stations as well as seasons. the depth of water column varied between 6.0 and 28.0 cm. the maximum value was recorded in station 1 and the minimum in station 3. the seasonal variation of the water depth was showed higher during monsoon season and lower during summer season (figure 11). meteorological observations the rainfall recorded during the study period (october 2007 to march 2010) is given in figure 12. the maximum rainfall was recorded during the month of november 2008 (1105 mm) and the minimum was in the months of march figure 6. monthly variations of nitrates in different stations during the study period. figure 7. monthly variations of nitrites in different stations during the study period. 2010 (6.2 mm). the quantum of rainfall was more (72.1%) during the northeast monsoon period (october to december). discussion the physico-chemical variable of the present study area is subjected to wide spatial temporal variation. rainfall is the most important cyclic phenomenon in tropical countries as it brings important changes in the hydrographical characteristics of the marine and estuarine environments. in the present study, the peak values of rainfall are records during the monsoon month (october to december). the rainfall in india is largely influenced by two monsoons viz., southwest monsoon on the west coast, northern and northeastern india and by the northeast monsoon on the southeast coast. the temperature is one of the important physical factors, which affects the chemical and biological reactions in water. it regulates the rate of photosynthesis in aquatic ecosystem. the temperature variation is one of the factors in the swamp and estuarine system, which may influence the physico-chemical characteristics and also influence the distribution and abundance of flora and fauna (soundarapandian et al., 2009). in the present study, it has been observed that high temperature is noticed in the months of april to june at all stations associated with longer photoperiod, bright sunshine and dry wind and lower temperature in the months of october to december was due to cloudy sky and rainfall brought down the temperature to the minimum. similar figure 8. monthly variations of phosphates in different stations during the study period. figure 9. monthly variations of total dissolved solids in different stations during the study period. observations have been reported by senthilkumar et al. (2002), santhanam and perumal (2003), gupta et al. (2008), sundaramanickam et al. (2008) and jayabhaye (2009) from different wetlands. salinity is one of the important factors which profoundly influence the abundance and distribution of the animals in estuarine environment and inshore waters. generally, the maximum salinity value is recorded during summer may be describe to the higher degree of evaporation in the study area. the low values are found during october to december is due to heavy rainfall and large quantity of freshwater inflow. similar trend in the salinity values were also observed from various parts in southeast coast of india (seenivasan, 1998; palanichamy and rajendran, 2000; sulochana and muniyandi, 2005; prabu et al., 2008; soundarapandian et al., 2009; damotharan et al., 2010). the effect of ph on the chemical and biological properties of liquids makes its determination very important. it is one of the most important parameter in water chemistry and measured as intensity of acidity or alkalinity on a scale ranging from 0 to 14. the ph concentration gets changed with time due to the changes in temperature, salinity and biological activity. most of the natural waters are generally alkaline due to the presence of sufficient quantities of carbonate (trivedy and goel, 1984). the ph remains alkaline throughout the study period at all stations registering a maximum during monsoon, which could be attributed to the high salinity of water. the high ph observe during monsoon season may be due to the influence of fresh water influx, dilution of sea water, low temperature and organic matter decomposition as suggested by ganesan (1992). similar trend in ph was reported by seenivasan (1998) from the vellar estuarine system, palanichamy and rajendran (2000) from palk bay, prabu et al. (2008) from pichavaram mangroves, damotharan et al. (2010) from point calimere coastal waters and sundaramanickam et figure 10. monthly variations of turbidity in different stations during the study period. figure 11. monthly variations of water depth in different stations during the study period. parangipettai and cuddalore coast of india. the oxygen dissolved in water is a very important parameter in water analysis as it serves as an indicator of the physical, chemical and biological activities of the water body. two main sources of dissolved oxygen are diffusion of oxygen from the air and photosynthetic activity. oxygen is considered to be the major limiting factor in water bodies with high concentration of organic materials. it is well known that the temperature and salinity affect the dissolution of oxygen (vijayakumar et al., 2000). higher dissolved oxygen concentration observed during monsoon season may be due to the cumulative effect of higher wind velocity joined with heavy rainfall and the resultant freshwater mixing (das et al., 1997; prabu et al., 2008; sundaramanickam et al., 2008; damotharan et al., 2010). nitrates are the most oxidized forms of nitrogen and the end product of the aerobic decomposition of organic nitrogenous matter. natural waters in their unpolluted state contain only minute quantities of nitrates. the recording highest nitrates value during monsoon / postmonsoon season may be mainly due to the organic materials receiving from the catchment area during rainfall (das et al., 1997). the increasing nitrates level is figure 12. monthly variations of rainfall in the study area during the study period. due to fresh water inflow, litter fall decomposition and terrestrial run-off during the monsoon / post-monsoon season (karuppasamy and perumal, 2000). another possible way of nitrates entry is through oxidation of ammonia form of nitrogen to nitrite formation (rajasegar, 2003). the low values records during summer / premonsoon period may be due to its utilization by phytoplankton as evidenced by high photosynthetic activity and also due to the neritic water dominance, which contained negligible amount of nitrate (rajashree and panigrahy, 1996; das et al., 1997; govindasamy et al., 2000). the peak values of nitrite observe during the monsoon may be attributes to the influence of seasonal rainfall. the higher concentration of nitrite and seasonal variation may also be attributes to the variation in phytoplankton excretion and oxidation of ammonia (kannan and kannan, 1996). low values of nitrite observed during the summer may be due to the lesser amount of freshwater inflow and higher salinity. similarly maximum value in monsoon and minimum value in summer season was also recorded by satpathy (1996) from coastal waters of kalpakkam, prabu et al. (2008) from pichavaram mangroves, sundaramanickam et al. (2008) from parangipettai and cuddalore coast and damotharan et al. (2010) from point calimere coastal waters, india. the phosphates are essential for the growth of organisms and a nutrient that limits the primary productivity of the water body. inorganic phosphorous plays a dynamic role in aquatic ecosystem, when present in low concentration is one of the most important nutrients. high concentration of phosphates observed during monsoon / post-monsoon seasons may possibly be due to intrusion of upwelling seawater into the swamp, which increased the level of phosphate. the result of low phosphates value during summer / pre-monsoon may be attributed to the limited flow of freshwater, high salinity and utilization of phosphate by phytoplankton (senthilkumar et al., 2002; rajasegar, 2003). the variation may be due to the various processes like adsorption and desorption of phosphates and buffering action of sediment under varying environmental conditions (rajasegar, 2003). turbidity is a measure of water clarity how much the material suspended in water decreases the passage of light through the water. in the present study, maximum turbidity is during monsoon season, while minimum value is during summer season. during monsoon season silt, clay and other suspended particles contribute to the turbidity values while during summer season settlement of silt, clay resulting low turbidity. bathusha and saseetharan (2007), garg et al. (2006), prasad and patil (2008), saravanakumar et al. (2008) and upadhyay et al. (2010) have also reported high turbidity during rainy season. the present baseline information of the physicochemical properties of water would form a useful tool for further ecological assessment and monitoring of this wetland of point calimere wildlife sanctuary. acknowledgements we sincerely acknowledge the department of forests, nagapattinam and chief conservator of forests for providing overall support during the fieldwork. authors are grateful to the management, principal, head of department and other staff of zoology, a.v.c. college (autonomous), mannampandal, india for providing necessary facilities. we sincerely express our thanks to the anonymous referees for their valuable comments on the manuscript. references anilakumary ks, abdul aziz pk, natrajan p (2007). water quality of the adimalathma estuary, southwest coast of india. j. mar. biol. assoc. india, 49: 1-6. apha (2005). standard methods for examination of water and wastewater. 21 st edition., washington d.c. bathusha 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karad, india. upadhyay k, mishra p, gupta ak (2010). studies on the physicochemical status of two ponds at varanasi and bhadohi under biotic stress. plant arch., 10(2): 691-693. vijayakumar sk, rajesh km, mendon r, hariharan v (2000). seasonal distribution and behaviour of nutrients with reference to tidal rhythm in the mulki estuary, southwest coast of india. j. mar. biol. assoc. india, 42: 21-31. welch mn (1952). limnology. mcgraw hill book co. inc., new york. nd springerverlag, new york. in ternationa l scholars journa ls african journal of environmental economics and management issn 2375-0707 vol. 7 (6), pp. 001-007, june, 2019. available online at www.internationalscholarsjournals.org © international scholars journals author(s) retain the copyright of this article. review environmental ethics: an african understanding ojomo p. a department of philosophy, lagos state university, ojo, lagos state, nigeria. e-mail: philoojomo@yahoo.com. accepted 16 february, 2019 global concerns about the current environmental crisis have culminated into some controversial environmental ethical theories, that is, normative environmental ethics, sentientist ethics, biocentric ethics, ecocentric ethics and eco-feminist ethics. one of the fundamental underlying features connecting these environmental ethical theories is their grounding in western perspectives and cultural experiences. given that environmental concerns are global concerns, and that the imperative of environmental ethics is challenging those life-threatening concerns, critical explorations of environmental ethics need to go beyond the western horizon. but with respect to the african perspective to environmental ethics and the people’s cultural understanding of the environmental crisis, little has been done in this penultimate area. however, segun ogungbemi and godfrey tangwa have pioneered philosophical discussions on environmental ethics from an african vantage point. hence, ogungbemi defends what he calls “ethics of nature-relatedness,” while tangwa proposes “eco-bio-communitarianism” as a definitive theory of an african orientation to environmental ethics. this paper is therefore a contribution to the consolidation of an african orientation to environmental ethics through a critique and reconstruction of some of the misrepresentations of the african perspective to the environment, implicit in the arguments of ogungbemi and tangwa. key words: environmental ethics, ethics of nature-relatedness, eco-biocommunitarianism. introduction africa has a complex history of valuable heritages as well as multifaceted challenges in her cultural-politico evolution. since primordial times, africans have had a humane and peaceful society and environment informed by a sound ethics. but owing to some internal dynamics in the people‟s culture and some other external constraints and forces, african states are now experiencing acute developmental challenges which have impacted negatively on their environment. besides political issues arising from leadership ineptitude and capitalist aggrandizement, which have brought about vices of corruption, injustice, poverty and underdevelopment of the continent, there is now a new dimension to the african crisis. and this is the environmental imbroglio. it is a known fact today that the environmental crisis is one of the most pressing concerns of our planet at the turn of the 21st century. as a global phenomenon, no society is totally immune against the threats and dangers which the environmental crisis poses to humanity and the rest of the ecosystem. but with respect to the african experience, a vast area of land rich in natural resources of all categories, flora and fauna of immense diversities, the dimension of the global environmental crisis in the continent has a peculiar character. the causes of environmental pollution and degradation, environmental injustice, poverty of effective coping and management strategies in challenging the environmental crisis, and lack of a viable environmental ethics that takes cognizance of the peculiar dynamics of the environmental crisis in africa are issues worth courting with philosophically. in this paper, therefore, we seek to explore the role of african philosophical thinking on the african environment in particular and the contemporary society and global world order in general. the primary aim of doing this is not to ethno-philosophically describe, merely, how traditional africans have managed their environment in pristine manner. also, the focus of our defense is not to establish the primacy or superiority of the african option over and above the existing theoretical perspectives in environmental ethics in western discourse. rather, the primary objective of this paper is to contribute to the consolidation of an emerging orientation in african environmental ethics and effective environmental management. this paper considers some fundamental questions such as: what is the condition of the african environment? why is the african environment more pathetic than other regions of the world? what are the efforts made and being made in the process of saving the african environment? do africans care for the environment? what are the factors to be considered in salvaging the african environment from further deterioration? what is the need for an environmental ethics that is african in orientation? how coherent is it with the existing known ethics of the environment: enlightened (weak) anthropocentrism, animal liberation/rights theory, biocentrism and ecocentrism (which include the land ethic, deep ecology and the theory of nature's value)? in addressing this host of fundamental questions, this paper proceeds with a discussion of ethics and the environment, after which it surveys the arguments of ogungbemi and tangwa, respectively on an african understanding of environmental ethics. finally, we posit some critiques of their argument. ethics and the environment ethics is a normative study of the principles of human conduct in relation to justice and injustice, good and evil, right and wrong, virtue and vice. it questions what ought to be done and the extent to which there is justification for a past action that had been done. by environment, we mean man and his surrounding, including the life support provided by the air, water, land, animals and the entire ecosystem of which man is but a part (osuntokun, 2001: 293). ethics has something meaningful to do with the environment, it questions humanity‟s relationship to the environment, its understanding of and responsibility to nature, and its obligations to leave some of nature‟s resources to prosperity (pojman, 1997: 1-2). environmental ethics is a field in applied ethics that asks fundamental questions about humans and the environment, it examines the moral basis of environmental responsibility. environmental ethics is a diversified discourse with competing different ideas and perspectives. generally, discourse on environmental ethics can be categorized into five schools of thought: enlightened (weak) anthropocentrism, animal liberation/rights theory, biocentrism, ecocentrism (which includes the land ethic, deep ecology and the theory of nature's value) (yang, 2006: 28) and eco-feminism. normative (and traditional) ethical theories (teleologism, utilitarianism and deontologism), which form the first category, are very anthropocentric and shortsighted in matters concerning the future generation as their reference to rights and duties are limited to the present generation. from an anthropocentric point of view, humans have a moral duty only towards one another, any duty they seem to have towards other species or entities is really only an indirect duty towards other beings. animal liberation/rights theory notably championed by peter (1975) expands the object of duty to include all animals and to all species in the universe. they contend that the pleasure and pain that animals experience are morally relevant, and that sentience is the necessary and sufficient condition for a creature to receive moral consideration. from the point of view of animal rights theory, the only right way to treat animals is to treat them as ends in themselves, never as mere means, because animals, like us, have rights that precede other's interests. as the holder of rights, animals deserve our respect. this theory has been criticized on the ground of being individualistic, and does not promote the interest of communities through common good and equilibrium of the entire ecosystem (fadahunsi, 2007: 6). in order to break radically from anthropocentric ethics, non-anthropomorphic environmental ethical theories emerged, the biocentric and ecocentric approaches. biocentrism maintains that all life forms are `moral patients' entities to which we should accord moral consideration. we therefore have a duty towards all forms of life. it is their telos that gives each individual organism inherent worth and that all living organisms possess this worth equally because all individual living beings have their telos. the equal inherent worth of all living beings warrants according to them, equal moral status: therefore, we must respect all living organisms (fadahunsi, 2007: 6). upon realization that biocentrism is not radical enough ecocentrism emerged and expands the definition of what is a „moral patient‟ to include nature as a whole. this implies respect for our fellow members and respect for the community as such. ecocentrism focuses on the integrity of the ecosystem and the value of species. under ecocentrism, we have the land ethic, deep ecology and the theory of nature's value. aldo (1966) summarizes the land ethic in the maxim: „a thing is right when it tends to preserve the integrity, stability, and beauty of the biotic community, it is wrong when it tends otherwise'. there are two notable basic ethical principles in deep ecology. the ecosphere egalitarianism principle says that all organisms and entities in the ecospere, as parts of the interrelated whole, are equal in intrinsic value (callicott, 1992). and all things in the ecosphere have equal rights to live and blossom and to reach their own individual forms of unfolding and self-realization. to harm nature is to harm ourselves, and to defend earth is self-defense. rolston's (1989) theory of nature's value derives our „duties‟ to nature from the „value in nature‟. according to this theory, nature is a kind of subject with teleology, creativity, intelligence and a capacity to value. instrumental value, intrinsic value and systematic value exist objectively in nature. these values in nature impose on us the imperative to care for the earth. humans, therefore, should be earth's moral overseers. ecocentrism, like the existing environmental ethical approaches before it, equally has its shortcomings. it is alleged that it leads to unacceptable treatment of individuals, and requires excessive sacrifice by humans (fadahunsi, 2007: 7). ecofeminism, as a school of thought and theory in environmental ethics seeks to end all forms of oppressions, including oppression of the environment. it does so by highlighting the interconnections between the dominations of humans by race, gender and class on the one hand and the domination of the earth on the other hand. it uses the lens of gender to reveal the logic of the interrelated dominations. ecofeminists like warren (1994) agree that there are important connections among systems of domination (for example, historical, literary, political, empirical, and ethical connections), and any adequate feminism, environmentalism, or environmental policy must recognize these connections. susan feldman notes the problem with ecofeminism when he points out that the claim that the domination of nature is wrong in the same way that the domination of women is wrong makes no sense, since domination can only be considered to be unjust when the object dominated has a will (feldman, 2007: 1). when we take a closer look at all the aforementioned theories, it is evident that each has its own internal problems, and the environmental ethical theories have been, to a reasonable extent, a creation of western scholastic mindset. it is worthy to note that the shortcomings of the various existing environmental ethical theories suggest the possibility of some further theories, which may not necessarily come from the western world. and given that environmental concerns are global concerns, and in view of the imperative of environmental ethics in challenging these life-threatening concerns, critical explorations of environmental ethics therefore need go beyond the western horizon. some african scholars have recognized the importance of this, and have consequently made some reflective leads in this respect. two of such scholars that shall engage our attention are: segun ogungbemi and tangwa godfrey. segun ogungbemi on an african perspective to the environmental crisis ogungbemi in his paper, “an african perspective on the environmental crisis,” discusses the nature of the environmental crisis in africa. in doing this, he came to a number of conclusions concerning the principal causes of the environmental crisis in africa and proposes some ethical reflections and practical suggestions on how to mitigate the challenges posed by the environmental crisis. ogbungbemi construes environmental crisis in global content as one of the greatest global problems of our time. in his thinking, environmental crisis is a conjunction of some natural disaster such as earthquakes, volcanic eruption and storms, together with man‟s activity of exploration and utilization of natural resources through the ingenuity of science and technology, which have impacted negatively on the environment. while recognizing the universality of the environmental crisis, ogungbemi notes that in understanding the nature of the environmental crisis within the content of sub-saharan africa, three points are sacrosanct: 1) ignorance and poverty 2) science and technology 3) political conflict, including international economic pressures. he argues that in order to properly understand the nature of the environmental crisis in africa, we need to understand the ways in which both traditional and modern social structures have led to environmental degradation. concerning the factor of ignorance and poverty, ogungbemi explains that the majority of traditional africans lived in rural areas where the people wallow in poverty, and lack basic amenities such as good water supplies, adequate lavatories and proper energy use. as a consequence, the rivers are polluted with human waste, exposing the people to avoidable water-borne diseases such as dysentery, typhoid and cholera. and the excessive use of fuel wood and constant bush burning which is a predominant practice in traditional africa, increases air pollution. this affects air quality adversely and depletes the forest and other natural habitats. this factor of poverty cum ignorance on the part of traditional africans, ogungbemi argues, “does not necessarily exonerate our people from their contribution to environmental hazards (ogungbemi, 1997; 204). this is particularly so given that the relevant patterns of behaviour may come, at least in part, from an inability to exploit nature because of low levels of economic and technological development. besides the crude contribution of traditional african societies to the world environmental crisis, mention must be made of the more catastrophic contribution of modern africa to the environmental crisis. ogungbemi is of the opinion that the drive to catch up with the developmental pace of the western world by african states government is responsible for the mass destruction of our ecosystem through unguided explorative engagements with african natural resources, the flora and fauna. many african nations are rich in resources but because their economies are not structured to take full advantage of these resources, they are exported with little or no 'value added'. the net results are relatively few jobs and other economic advantages (that are often siphoned by the corrupt elite), as well as considerable environmental damage. moreover, this damage often results in loss of agricultural land that the poor rely upon, and significant pollution of waterways. ogungbemi argues that the way in which natural resources such as land, water and air are being used goes contrary to the traditional practice of environmental conservation. (ogungbemi, 1997: 205). with respect to land for instance, the drive to develop has led to increased deforestation with its incalculable effects on turbidity, erosion, flood and desertification. in another instance, “in its bid to catch up with developed nations, modern africa has exploited some of its essential minerals, namely: gold, copper, oil, diamonds, coal, uranium, etc., thereby creating ecological imbalance and environmental problems. water is another essential natural resource that has been adversely affected in modern africa through human activities. the deposition and dumping of toxic waste on the african coasts and inland by industries, both within and outside the continent, pollution of water through oil exploration and spillage, and through bacteriological and chemical agents like fertilizers have made our waters unsafe not only for humans but also other species in our waters. ogungbemi further pointed out how air, which is an essential natural resource for living, has been threatened by human techno-scientific activities. most fundamental in this regard is the uncontrolled nature of the emission coming out from automobiles, industrial machines, artillery air raids and such likes. in addition to the causes of pollution of the air, land and water in africa, ogungbemi equally identified the unprecedented population growth in contemporary africa as another factor that has continued to aggravate the destruction of the environment in africa. the logic here is that, the more the population, the more the stress on the natural resources and consumption ipso facto increases. more consumption results in more disposal of waste and where waste is carelessly managed as it is the case in many african states, the more the hazard the environment is prone to. it needs be stated that however, ogungbemi says that it is not clear whether population, by itself, is the key problem. rather, it is inequitable distribution of global wealth. granted that many african traditional folks as well as their contemporary counterparts have in some ways contributed to the general environmental problems of the world today, ogungbemi equally underscores how traditional africans have loved nature with respect and awe. he writes on traditional environmental management. in our traditional relationship with nature, man and women recognize the importance of water, land and air management. to our traditional communities the ethics of not taking more than you need from nature is a moral code. perhaps this explains why earth, forests, rivers and wind and other natural objects are traditionally believed to be both natural and divine. the philosophy behind this belief may not necessarily be religious, but a natural means by which the human environment can be preserved. the ethics of care is essential to traditional understanding of environmental protection and conservation (ogungbemi, 1997: 204). by ethics of care, ogungbemi (1997: 208) meant an orientation in which one is not taking more than one‟s needs from nature. however, ogungbemi is quick to note that this moral code is not unique to african societies as it has a universal appeal and applications, and that there are some interlocking questions that may obliterate its sensibility and justification and adoption in contemporary african order. pertinent among these questions are: how do we know how much we need, given the nature of human greed and insatiability? who judges whether we have been taking more or less than we need from the natural resources? if we have been taking more than we need, what are the penalties and how fair are they? (ogungbemi, 1997: 208). the fundamental questions raised by ogungbemi are quite strong and as a consequence, he attempted a reformulation of the traditional environmental practice of “ethics of care” in order to make it applicable to contemporary african situation. this conceptual reformulation is what ogungbemi (1997: 208) called “ethics of nature relatedness. according to him, “ethics of nature-relatedness asserts that our natural resources do not need man for their existence and functions…. the ethics of nature relatedness can be succinctly stated as an ethics that leads human beings to seek to co-exist peacefully with nature and treat it with some reasonable concern for its worth, survival and sustainability (ogungbemi, 1997: 208209). in ogungbemi‟s submission, ethics of naturerelatedness has three basic elements: reason, experience and the will. it does not attribute natural resources to a spiritual nature nor does the creation of natural resources have any religious affinity. with this new ethical thinking, ogungbemi‟s expectation is that our present reckless use of nature can be curtailed. in addition to this environmental ethics he envisages, he offers some practical suggestions on how to mitigate the current environmental crisis in africa. first, he suggested the generation, transmission and distribution of solar energy at a reasonable cost as a safety value in reducing african over-reliance on firewood, coal, kerosene, gas and petrol as sources of energy. secondly, on the issue of population, ogungbemi prophesized that “when our population has reached an alarming situation, nature will invariably apply its break (through volcanic eruptions, earthquakes, etc.) and have a drastic reduction in our population growth rate. thirdly, he recommended a turn-around in africa‟s political leadership in order to put in place good policies that are environmental friendly. he urged them to demonstrate the political will that is necessary for reducing the amount of industrial and agricultural wastes and properly dispose of them so that both our industrial and commercial centers, as well as our rural areas are safe from air and water pollution (ogungbemi, 1997: 209). there are some critical problems in ogungbemi‟s idea of environmental crisis in africa and his environmental ethics. but before exposing these, it suffices to note first, the perspective of godfrey tangwa on an african orientation in environmental ethics. godfrey tangwa on an african perspective to environmental ethics tangwa is another african philosopher that has made some reflections and contributions toward creating philosophical awareness on the need for an ethic of the environment in africa. though his work has no reference to the earlier work of ogungbemi, but their point of focus is essentially similar. that is, towards developing an environmental ethics that can confront environmental crisis. in his paper, “some african reflections on biomedical and environmental ethics,” tangwa bases his conception of an african orientation in environmental ethics on the metaphysical outlook of pre-colonial traditional african societies, which he called “eco-bio-communitarianism.” this metaphysical worldview involves the “recognition and acceptance of inter-dependence and peaceful coexistence between earth, plants, animals and humans” (tangwa, 2004: 389). this metaphysical outlook underpinned the ways, manners and cosmically relations between human and his fellow humans. it is also responsible for why traditional africans were more cautious in their attitude to plants, animal and inanimate things and the various invisible forces of the world (tangwa, 2004: 389). tangwa noted that traditional africans were more disposed towards the attitude of „live and let live‟. he emphasized further that within the traditional african metaphysical worldview, the dichotomy between “plants, animals, and inanimate things between the sacred and the profane, matter and spirit, the communal and the individual, is a slim and flexible one” (tangwa, 2004: 389). it is in line with this metaphysical framework that one can consistently and coherently situate the people‟s belief in transmigration of the soul into animals, plants or into forces such as the wind. on the basis of this metaphysical understanding of nature and the nature of man, tangwa says such a mindset has very significant implications for the way nature is approached and treated by traditional africans. illustrating his positions on the conciliating relation between humans and the environment in traditional african culture, tangwa cited the instance of his own culture, the nso in cameroon. according to him, the “nso‟ attitude toward nature and the rest of creation is that of respectful co-existence, conciliation, and containment, there are frequent offerings of sacrifices to god, to the divine spirits, both benevolent and malevolent, to the departed ancestors and to the sundry invisible and inscrutable forces of nature” (tangwa, 2004: 390). in all these, the point of tangwa is that african culture is not against technology whole handsomely, but consistent with cautions and piecemeal use of technology. and given the respect for natural human values that adorn traditional african culture, there are some lessons to be learnt by western culture that has subjected such values to the caprice of the god of technology, industrialization and capitalism. as against the western worldview, which tangwa sees as predominantly anthropocentric and individualistic, african worldview, he maintains, is eco-biocommunitarian (tangwa, 2004: 392). this distinction notwithstanding, tangwa is aware that, that does not necessarily have an automatic consequence on the environment. he holds: an anthropocentric ethic, even an individualistic one, if it were sufficiently rational, need not necessarily endanger the environment, just as an eco-bio-communal one may not necessarily forestall all dangers to the environment (tangwa, 2004: 392-393). the point tangwa is making is that there is nothing wrong with the technology in and of itself but only with the motivation for its development and the uses to which it is put. he condemns the motivation for development of western technology and the uses to which it has been put, which he identified as the will to possess and dominate the world. in his submission, a more humble motivation for the pursuit of science and technology based on the eco-bio-communitarian attitude of „live and let live‟ can be substituted for the aggressive motivation of domination to the immeasurable advantage of the whole of mankind (tangwa, 2004: 394). some critical comments on african orientation in environmental ethics ogungbemi‟s proposal of a reconstructed return to the traditional attitude reflected in the "ethics of care" regarding our interactions with the environment led him to what he termed “the ethics of nature-relatedness.” this ethics of nature-relatedness is not a preservationist approach, nor is it in any way non-anthropocentric. it does not even imply, as he observes, “that natural resources actually have a spiritual nature” (ogungbemi, 1997: 208). rather, it is an approach that recognizes that humans necessarily rely upon the natural world for existence. because of this reliance, we must treat the environments in which we live with due respect for the sake of current and future human well being. one major problem with ogungbemi‟s ethics of nature-relatedness is that it bears little affinity or no semblance with african cultural experience and ontology. it is not grounded in the metaphysics of african cultural belief system. though ogungbemi‟s discourse shows a good understanding of the african dimension of the environmental crisis, especially with his analysis of the traditional and modern african societies‟ contributions to the complexity of the environmental crisis, his position on the needed environmental ethics is alienation of the african spirit and peculiar experiences. as he rightly noted, environmental problem in africa and anywhere else, is primarily a consequence of human actions. and as value systems inform our actions, we need to search for a viable environmental ethics that is in agreement with african ontology. this is essential in order to pave way for environmental policies that will be compliant with the historic cultural experiences of the people. in fact, ogungbemi‟s alarming recommendation that nature should invariably apply its brake through volcanic eruptions, earthquakes, and others in order to have a drastic reduction in africa‟s population growth rate is reflex of the disconnectedness of his ethics of naturerelatedness and african ontology. the aforementioned mark of deficiency in ogungbemi‟s ethics of nature-relatedness is the strong point of tangwa‟s environmental ethics of eco-biocommunitarianism. though, not without its own problem, the merit of tangwa‟s position is that he recognized the indispensability of african metaphysics in the construction of a meaningful african environmental ethics. the absence of the dichotomy between plants, animals and inanimate things, between the sacred and the profane, matter and spirit, the communal and the individual in the african metaphysical worldview informed the traditional african disposition and attitude of „live and let live‟. such metaphysics is not one of domination instigated by greed nor is it consumerist in nature. the belief is that there is reason for whatever is, although man may not know immediately why a thing is created, but they all serve a purpose. being is therefore conceived as the whole range of existent things. latent in that metaphysics are folkloric assertions and certain taboos that are conservational of ecological balance of the environment. the problem with tangwa‟s exploration of an african environmental ethics is that it is an ethno-philosophical defense of indigenous african treatment and management of the environment. he never recognized the ways and manners by which traditional africans contributed to the degradation of the environment, albeit ignorance and poverty. this is the strong and commendable point explicit in ogungbemi‟s position. in the accounts of both ogungbemi and tangwa, some fundamental questions, which are critically essential to a plausible african orientation in environmental ethics, are left un-raised let alone discussed, what should be the nature of african obligation and role of the relationship between africans (non-africans in africa inclusive) towards the future generation in africa, sentient beings, non-human animals, african environment in particular and nature in general? what is the need for an environmental ethics that is african in orientation? and must such be exclusionary of the existing known environmental theories from the west? what are the political, cultural, economical, educational, legal, and moral imperatives to be taken into consideration in the construction of an african environmental ethics in order to salvage the african environment from further deterioration? while it is not the primary task of this paper to explore in details, considerations of answers to the aforementioned raised questions, it is significant to note that the questions are meant for further examination in a separate study. be that as it may, the solution to environmental destabilization is not purely technological or exclusively attitudinal. environmental ethics no matter how grounded in african experience it could be or intellectually sophisticated it could be, cannot alone solve the environmental crisis in africa. there has to be an orientation that keeps in mind the various imperatives as mentioned previously, as well as other recommendatory notes: bearing in mind that improved technology, which is at the root of the environmental crisis, is still much inevitably craved for in africa and cannot be done without in our today‟s world, it is our recommendation that only technologies, which are more benign to the environment, should be developed in the continent and allowed to be imported into africa. this will aid in curbing the use of environmentally harmful technologies. it is a possibility that testing how harmful some technologies are may not be immediately foreseeable or proven, in such instances, the technologies can be deemed guilty until proven innocent. this reasoning is premised against the backdrop that it is better to eliminate potential hazards and err on the side of caution, than to discover hazards when much damage has already been done. this should be the attitude towards science and technology in africa. the green technology of bio-fuel is environmentally friendly efforts in this regard. currently, the world is assiduously moving towards green technology, especially the use of bio-fuels at the detriment of the use and of fossil fuels. though economically expensive and at present, africa may be lacking in the technical skills and human capital requisite for the smooth adoption of this technology in her shores, the cosmopolitan onus falls on the developed nations to assist africa without exploitation, in matching up with the current pace. this perhaps informed the debate at the recently concluded conference in cancun, where rich nations were encouraged to help (through funding) poor nations tackled environmental problems. environmental managers of existing regulatory bodies in africa must ensure that organizations and agencies meet local and international environmental standards and other legal policy requirements. government and non-governmental bodies have to do their part in ensuring a good environment in africa. this ought to be done through public enlightenment of the need to preserve and protect the environment. in the absence of proactive environmental awareness campaign, many see environmental agencies as avenues created for siphoning financial interests from the government and soliciting for international loans. the adoption of a more pragmatic approach by these bodies in the issue of environmental concern will instill environmental consciousness in the minds of many (nneji, 2010: 37). furthermore, environmental consciousness and appreciation should be instilled into students through the introduction of environmental issues in their course contents. such environmental issues and topics should aim at making students appreciate the principles of sustainability as it relates to biodiversity, non-renewable resource and the quality of human life in the biosphere. also, cognizance of the improvement in compliance to environmental laws, environmental policies and regulations should be revisited to deal seriously with the attitude of recklessness towards the environment. this is with special reference to the business sectors that are almost insensitive to environmental concerns. in curbing such negligence, every business organization must be compelled to conduct an environmental impact assessment (eia) and produce such report before the corporate affairs commission (cac) can register it. the corporate affairs commission is the body in charge of the registration of business organizations in nigeria. many of such bodies do exist in other african countries (nneji, 2010: 39). conclusions the point of this paper on an african orientation in environmental ethics should not be misconstrued. it is not seeking for an entirely unique environmental ethics for the african world alone. rather, its point of emphasis is that, not just any environmental ethics will do for the continent because of certain peculiarities in environmental degradation in africa. if need be, there could be borrowings from the existing western ethical approaches to the environment, but such borrowings must critically have in addition, a concern for the african environmental experience. while the known environmental ethics in western discourse are not infallible, their respective deficiencies left us open to the question of which ethics is most appropriate and ought to be embraced in effectively challenging the african condition. the task of fashioning what should constitute the ethical principles of the african environment is one of the most fundamental challenges and issues contemporary african philosophy continent must deal with. not until this intellectual imperative is settled, collaborative efforts by government, ngos, environmental agencies and mangers, as well as other sub sectors of the society towards orientation and sensitization, policy formulation and implementation on sustainable environment in africa would not yield the desired result. finally, and more importantly, consideration of profit rather than human need, must be looked into seriously by multinationals and rich nations. the reckless exploitation of the environment is borne out the value placed on profit. and as long as powerful predatory nations of the world continue to exploit poorer nations, as long as they fail to treat these poor nations with respect, environmental crisis will remain or become even more serious than we experience it today. we must accept the fact of interrelatedness of the world, the interconnectivity of the entire globe. whatever happens in one part of the world, affects other parts. since this is the case, the philosophy of exploitation must be dropped for the philosophy of respect for, not only persons, but for nature as well. references aldo l (1966). a sand county almanac: w ith essays on conversation from round river. new york: oxford university press. fadahunsi a (2007). “challenging africa's environmental crisis: the ethical imperative.” www.utexas. edu/conferences/africa/ 2009/09abstracts_a-g.htm. nneji b (2010). “eco-responsibility: the cogency for environmental ethics in africa.” essays philos., 11: 1. www.commons. pacificu.edu/eip/vol11/iss1/5. ogungbemi s (1997). “an african perspective on the environmental crisis.” in pojman, louis 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"the power and promise of ecological feminism." reprinted in donald van deveer and christine pierce. the environmental ethics and policy book. belmont, ca: wadsworth publishing co. yang t (2006). "towards an egalitarian global environmental ethics." in environmental ethics and international policy. paris: unesco. in ternationa l scholars journa ls african journal of environmental economics and management issn 2375-0707 vol. 6 (1), pp. 374-383, january, 2018. available online at www.internationalscholarsjournals.org © international scholars journals author(s) retain the copyright of this article. full length research paper a study of the potentials of traditional natural resources management for biodiversity conservation *jagdish bihari gangadhar, manmohan khan and akshay ram premji department of zoology, l. s. m. government post graduate college, pithoragarh, uttarakhand –262502, india. email: jagdish.bihari@gmail.com accepted 18 august, 2017 social taboos exist in invariably all cultures throughout the world, and represent a class of informal institutions, where traditional, religiously governed norms or taboo system define the human behaviour. these taboos remain the prime factor guiding their conduct towards the exploitation of the natural resources. however, the singular role played by these informal systems of taboo in conservation of biodiversity has not been given its due importance. the present paper attempts to render forth the salient aspect of conservation borne out of the taboo system in practice surrounding the sacred natural sites, principally the sacred forests, in the state of uttarakhand, central himalaya. the study brings forth the fact that although the potential of traditional natural resources management for biodiversity conservation vis a vis the institution of taboo within the state remains enormous, the sustainability of these practices however is seriously threatened. in fact, the dilution of the traditional beliefs and associated taboos, principally borne out of the western type education, along with social and economic factors, underpinning traditional natural resources management practices were found to be the greatest threat to the sustainability of these practices. there is thus an urgent need to investigate local perceptions of forest space and landscape, biodiversity conservation and traditional beliefs, and their significance for natural resources management, towards understanding the changing values of local people in relation to traditional protected areas, such as sacred forests. key words: conservation, culture, informal institutions, sacred forests, social taboos, traditional knowledge-based systems. introduction the term ‘taboo’ is derived from the polynesian word ‘tapu’, and is defined as a ‘prohibition or a ban’. social taboos represent good examples of informal institutions (north, 1990), which are based on cultural norms that do not depend on government for either promulgation or enforcement (posner and rasmusen, 1999). institutions are here defined as the rules and norms that structure human interaction, including their enforcement characteristics and sanctioning mechanisms (north, 1990), and include any form of shared constraint that human beings devise to shape their daily interactions and transactions. such institutions are decentralized and self-enforced by a community, where no external authority is available to guarantee that social actors will abide to rules and procedures (knight, 1992). formal institutions, in contrast, are rules that human beings devise, such as written rules, laws and constitutions and are highly associated with the structural complexity of industrialized nations and their division of labour (north, 1990). the traditional natural resources management are infact shaped around the local rules and regulations (ntiamoa-baidu, 1995; abayie, 1998), most often enshrined in religious or cultural beliefs and superstitions, and enforced by taboos, which dare not be infringed upon, and thus making the whole exercise, an effective one. informal institutions, such as taboos, have largely been neglected in conservation designs, where park protection has been the major approach for protecting biodiversity (mcneely, 1993), and thus it is strongly believed that the same could play an active role in nature conservation jagdish et al. 375 (murphree, 1994). in fact, very often, it has been observed that social taboos may be highly adaptive from an ecological perspective and which contributes to biodiversity conservation (colding and folke, 2001); that it often applies to certain sets of natural resources that are particularly vulnerable to overexploitation (colding and folke, 2001). anthropologists have ascribed various social functions to taboos: (i) they function to distinguish between sacred and profane entities in a culture (durkheim, 1915); (ii) relate to animist and magical belief systems (frazer, 1922); (iii) serve psychological ends (malinowski, 1922); and even (iv) serve ecological adaptations (rappaport, 1968). infact, it may be difficult to distinguish among ecological, social, or religious origins and functions of taboos (colding and folke, 2001). taboo often apply to certain sets of natural resources, which are particularly vulnerable to overexploitation, and thus the imposition of temporal taboos regulates access to resource(s) on either a sporadic, weekly, monthly or even seasonal basis (colding and folke, 2001). the efficacy of the social taboos becomes all the more conspicuous, when one encounters yet another traditional institution, the institution of sacred natural sites. for example, when a sacred forest cover located above the precincts of the village, is zealously guarded, with taboo not to infringe upon or make resource use from it, and thus the perennial water flow (with its source being the conspicuous sacred forest lying above) and its associated benefits for the very sustenance of the village folks, need not be exemplified further. in fact, amongst most ethnic groups, there exist beliefs that regard the majority of water bodies as abode of deities, and thus taboo against making recurrent visits to the source of the same (read the sacred forests) were effective in protecting these sources, especially those that served as potable water sources for a community or group of communities, with major examples being offered by the sacred forests of hariyali devi, madhkeshwar, maanthaat, shyama devi, jal devi, etc (table 1). infact, defilement of the water remains one of the greatest sins, as per the religious scripts, brought forth by the natives. and hence, the present study delves into the social taboo system in practice surrounding the sacred natural sites. the ‘sacred natural site’ here is defined as a reserved space, established by a community, a group of people or an individual, following the conventions based on specific phenomena and requiring the respect of engagements taken at this place in order to satisfy the spiritual, cultural and socio-political needs while focusing on the harmony and wellbeing of the native community, as well as of the whole humanity (kamga-kamdem, 2008). the above definition most appropriately brings forth the salient aspect of the ‘institution of sacred sites’, that is, the mode of its establishment, the people entitled to this purpose, the beneficiaries, the very objectives of establishment, and the management rules that govern, principally the resource use from the sacred forests. materials and methods the knowledge based-systems methodology for acquisition of local ecological knowledge suggested by sinclair and walker (1999) was adapted, involving knowledge collection from a small sample of deliberately chosen individuals, thought to be knowledgeable by other villagers about the domain of interest. the knowledge was collected through repeated, structured (questionnaire-based) interviews, with information being sought as regards the location of sacred natural sites (sns), features related, local perception about the sacredness of the sns, and management (inclusive of caste dynamics). priorly, the informants were given a brief background of the subject area of interest (viz., the concept of the sacred natural sites), in their native tongues, as and when required, so that the requisite information could be gathered. since the domain of study, that is taboo system surrounding the sacred sites was governed by dominant castes, principally brahmins and the rajputs, with lower castes relegated to carrying out profunctionary functions/tasks, it was inevitable that interviews be conducted across the different class of people, so that an overall picture of the taboo system could emerge, and hence, efforts were made to interview a minimum of 6 8 persons across the class/caste divide per site/village, and thus, altogether 168 sacred natural sites (henceforth sns), including 75 sacred forests, 74 sacred groves, 10 water bodies and 9 pastures, and extending across the nine hilly districts of the state were covered for the study of existent taboo system (figures 1 and 2), and a total of 1262 informants interviewed. however, for myriad reasons (say, in most of the sites, the population was wholly constituted of one, or at times only two castes-brahmins and the rajputs, and hence, in such cases, the resource management specialists-the leaders and the wise people, that is, mostly the elderly folks were consulted. results and discussion traditional natural resources management system in practice in uttarakhand, can be classified into the following broad categories: (i) protection of particular ecosystems or habitats (such as sacred groves and forests); (ii) protection of particular animals or plant species (as totem or tabooed species); and (iii) regulation of the exploitation of particular natural resource (such as a closed season for resource harvesting). however, the taboo system surrounding the sacred natural sites has been dealt as per classification of social taboos (colding and folke, 2001), principally into (i) segment taboos, (ii) temporal taboos, (iii) method taboos, (iv) life history taboos, (v) specific-species taboos. segment taboos the following group of taboo applies when a cultural group bans the utilization of particular species for specific time periods for human individuals of a particular age, sex, or social status (colding and folke, 2001). thus, certain segments of a human population may be 376 afr. j. envir. econ. manage. table 1. some of the selected sacred natural sites with conservational value # (negi, 2010). district area floral dominant species s. nosacred natural sitenature diversity (ha) 1 brijkang, ralam pasture 60 2 raghunath, tola forest 5 3 suraj kund, milam water body 40 4 bhujani, martoli forest 12 5 dharmbun sem, pasture 105 laspa 6 hya roshey, pasture 40 napalchhu 7 dhan ki kheti, pasture 145 jyolingkong 8 nigalfu, sipu pasture 120 74 picrorhiza kurrooa, juniperus communis * abies pindrow 78 rhododendron anthopogon, danthonia sp. betula utilis, rhododendron campanulatum 73 dactylorhiza hatagirea, carum carvi euphrasia himalayica, cicerbita violoides, 42 polygonum viviparum, bupleurum sp., potentilla cuneifolia, p. atrisanguinea euphrasia himalayica, polygonum viviparum, 34 potentilla argyrophylla betula utilis, juniperus communis, aster stracheyi, euphrasia himalayica, potentilla 37 cuneifolia, p. argyrophylla, geranium grevilleanum 9 bombasing, tedang forest 5 abies pindrow, betula utilis, pinus wallichiana. 10 sangfa fu, baun pasture 20 48 juniperus communis, rhododendron anthopogon pithoragarh betula alnoides, cedrus deodara, celtis australis, lyonia ovalifolia, myrica esculenta, 11 kokila devi, kanaar forest > 20 sq km 73 pinus roxburghii, quercus leucotrichophora, q. semecarpiflora, rhododendron arboreum, r. campanulatum, taxus baccata q. leucotrochophora, q. dilatata, alnus 12 hokara devi, hokra forest 5-6 nepaulensis, aesculus indica, pinus wallichiana, 13 thal kedar forest 15 q. leucotrochophora, q. dilatata, myrica nagi, rhododendron arboreum 14 lateshwar forest 4-5 quercus leucotrichophora 15 dhawaj forest 15 q. leucotrochophora, q. dilatata, myrica nagi, rhododendron arboreum q. leucotrochophora, rhododendron 16 ghandhura forest 20 arboreum, q. semecarpifolia, thamnocalamus sp. syzygium sp. 17 syangse gabla forest 3-4 abies pindrow 18 nakuleshwar forest 3-4 quercus leucotrichophora 19 jagatnath forest 4-5 diploknema sp., ficus sp, 20 nagarjuna forest 2 acacia sp. 21 jal devi forest 2 quercus leucotrichophora, myrica esculenta, rhododendron arboreum 22 byandhura forest 5 sq km tropical mixed forest 23 mallareshwar forest cedrus deodara, pinus roxburghii, myrica esculenta, rhododendron arboreum champawat quercus leucotrichophora, q. semecarpifolia, 24 gorakhnath forest 5 sq km q. glauca, symplocus chinensis, lyonia ovalifolia, cedrus deodara, myrica esculenta, pyrus pashia, rhododendron arboreum cedrus deodara, quercus semecarpifolia, q. almora 25 vishnu forest 16 leucotrichophora, aesculus indica, ficus spp., myrica esculenta, rhododendron arboreum shihyayi/ quercus semecarpifolia, q. leucotrichophora, 26 forest 5-6 aesculus indica, myrica esculenta, shyama devi rhododendron arboreum 27 aeri dhura forest 8-10 quercus leucotrichophora, myrica esculenta, rhododendron arboreum table 1. contd. district s. no sacred natural site nature area floral dominant species (ha) diversity quercus semecarpifolia, q. leucotrichophora, almora 28 anyar bunga aeri forest 10-12 aesculus indica, myrica esculenta, rhododendron arboreum, anyar, alnus nepaulensis. rhododendron arboreum, myrica esculenta, 29 sidh baba forest 10-12 anyar, quercus leucotrichophora, q. semecarpifolia, aesculus indica cedrus deodara, myrica esculenta, 30 thatyur forest 67.2 rhododendron arboreum, quercus dehradun leucotrichophora, q. floribunda, q. semecarpifolia 31 maanthaat forest 15 cedrus deodara 32 danda ka deorana 20 cedrus deodara pinus roxburghii, quercus leucotrichophora, 33 kamleshwar forest 10 sq. km q. floribunda, cedrus deodara, pinus uttarkashi mahadev excelsa, rhododendron arboreum, myrica esculenta, celtis australis 34 madhkeshwar forest 15 sq. km cedrus deodara 35 bhadrakali forest 10 cedrus deodara tehri 36 sem mukhim naag forest 60 quercus leucotrichophora, q. floribunda, q. garhwal semecarpifolia, rhododendron arboreum 37 ulkhagarhi forest 5 sq. km quercus leucotrichophora, q. floribunda, rhododendron arboreum, myrica esculenta pauri cedrus deodara, quercus leucotrichophora, garhwal 38 tarkeshwar forest 5 sq. km 343 q. floribunda, q. semecarpifolia, myrica esculenta rudraprayag 39 hariyali devi forest 5 sq. kms quercus semecarpifolia, q. leucotrichophora, aesculus indica, myrica esculenta, rhododendron arboreum, celtis australis # conservational valueprincipally in terms of biodiversity content; providing the only refuge for the wild faunal spp., or as the only source of water. *diversity assessment has not been attempted. temporarily proscribed from the gathering and/or consumption of species. anthropologists often refer to such taboos as specific food taboos (rea, 1981). segment taboos frequently pertain to pregnant women, children, menstruating females, and parents of newborns. cultural perceptions, customs, and superstitious beliefs of human health risks are frequently related to such taboos (osemeobo, 1994). thus, segment taboos are often related to totemic beliefs, which reflect cognitive and linguistic categories, useful to the natives of these cultures (posey, 1992). additionally, few anthropologists have hypothesized that segment taboos may also serve as strategic responses to avoid game depletion (ross, 1978; hames and vickers, 1982). in the present case study, this taboo relates to the complete banning of the lower castes, the harijans from not just the resource exploitation, but also from entering into the sacrosanct zones or the sacred natural sites that is, mostly the sacred forests, and the water bodies. this apart, the other most conspicuous extension of the taboo, and the most commonly ascribed, is the ban extended to the partruting and the menstruating females, who irrespective of the caste, are banned from entering into the restricted zones. the issue of menstrual blood in traditional beliefs has been treated extensively in anthropology as a source of potent force (douglas, 1966). it may be conjectured that women, who were considered to be the most frequent users of water, were prohibited from entering the vicinity of rivers when they were menstruating to prevent degradation or defilement of the sacred water. in most communities rivers provided the main source of jagdish et al. 377 378 afr. j. envir. econ. manage. 5% 6% 44% 45% groves forests alpine pastures water bodies figure 1. the percentage distribution of the sacred natural sites (sns, n= 168) across the state of uttarakhand. n u m b e r o f th e s a c re d n a tu ra l s it e s 60 grove (44%) 50 forest (45%) alpine pastures (5%) (s n s ) 40 water bodies (6%) 30 20 10 0 pithoragarh a t g li n hi garhwal l a r pawa a o du w o y m s m a a garh r a a rk al p h ehr tta cha m a c d ri dr u tehri u u r districts covered pa figure 2. the relative distribution of the sacred natural sites across the state of uttarakhand. drinking water (ntiamoa-baidu, 1995). the exclusion of women from certain religious festivals and ritualistic observances like their periodical segregation during their menstrual period appears to be due not to any assumed inferiority on their status but due to the tribals’ horror of menses, which is supposed to attract evil spirits. from conservation aspect, it seems appropriate that the womenfolk, representing the dominant workforce involved in the resource exploitation (including the banks of the rivulets and rivers, example ‘latu ka gadera’, explained later under the sub-heading habitat taboos), throughout the hills, this ban extending for the duration of the menstrual cycle, significantly restricts the resource withdrawal; more so, when this taboo forms the predominant class of taboo, finding expression in nearly all the sns, solely, as well as admixed with other taboos (figure 3). temporal taboos the temporal taboos apply when a cultural group bans access to resources during certain time periods, and are thus imposed sporadically, daily, or on a weekly to seasonal basis (colding and folke, 2001). taboos imposed on a weekly to monthly basis are often referred to as a "closed season", which very often coincides with jagdish et al. 379 table 2. broad classification of taboos restricting the resource use in uttarakhand (adapted from colding and folke 2001). s/no. class of taboo example a. segment segment of population observing the taboo 1 scheduled castes pregnant and menstruating females, women 2 after child birth 3 pubescent girls 4 particular caste a common feature throughout the state of uttarakhand, where lower castes are debarred to enter the sacred forests. very often, this often leads to the phenomenon where the debarred caste create their own sacred groves, viz., ratashila sacred grove in district pithoragarh the most common sited reason debarring the womenfolk’s’ entry into the sacred natural sites as above though rare, but at times even a class of upper castes too are tabooed to enter into sacred forests, viz., aswals, a higher caste rajputs are debarred from entering into the tarkeshwar sacred forest in district pauri garhwal b. temporal taboo restricting the resource use (principally from the sacred forests) 1 exploitation of resource on a seasonal basis 2 exploitation of resource on an annual basis 3 complete ban on the resource harvesting the most commonly observed resource exploitation pattern; very often the case were the sacred forest do not usually constitute the watershed the sacred forests of chopakya, jagatnath, and jujarimal; as well as the sacred meadows of bhadelguar, hya roshe, kee pang (all within askote conservation landscape). the sacred forests of manthaat, hariyali, madhkeshwar, tarkeshwar, thamri kund and hokra devi, among others. c. method taboos primarily restricting the resource use, as well as providing protection 1 2 3 4 5 6 all leather goods, especially the shoes 7 days prohibitory period 3 months prohibitory period regulatory means to make use of the sacred water hunting of wild animals on tuesday, friday and saturdays annual harvesting of fishes examples include the famous nanda raj jaat, and the chipla kedar jaat examples include the sacred forests of thamri kund, kotgyari devi, dhoulinag, and chamunda devi. examples include the sacred forests of kotgyari devi, and jyastha masaani devi. defilement of the sacred water is protected by means of certain provisions, where the locals are forbidden to procure water directly from the water body. the best examples are the thamri kund, muldi bai, syangchu kund (kund syn. pond). hunting, a strict taboo on the prescribed days, viz., in case of the sacred forests of kalsin, tiundhar, and devidhar. during the annual maun festival in jaunsar valley in dehradun district, the locals collectively engage themselves in a large-scale communal hunt of fish, where powder of timru (zanthoxylum armatum) is poured into the river in sackfuls. poisonous affects of the powder makes the fish an easy catch. the whole exercise might be effective towards adjusting the resource harvest practices to sustain yields and thus conserve biodiversity (gadgil et al. 1993). d. life historyregulates withdrawal of vulnerable life history stages of species exploitation of immature brahmkamal 1 (saussurea obvallata) 2 hunting of pregnant does nanda astami festival in martoli village in johaar valley. this aspect is rather commonly observed throughout the landscape. institution of mrigoli as practiced in hariyali devi sacred forest forbids hunting of pregnant does e. species-specifictaboo banning the exploitation of the individual species fiya or himalayan marmot (marmot bobak) is a totem; serow (cervus 1 hunting of wild species unicolor) within the sacred forest surrounding the thamri kund 380 afr. j. envir. econ. manage. table 2. contd. kharik (celtis australis), malu (bauhinia vahlii), paiyan (prunus ceresoides), 2 exploitation of sacred species deodar (cedrus deodara), shiling (osmanthus fragrans) are some of the most commonly religiously protected species in the state of uttarakhand. f. habitat taboos restricts access and use of resources in time and space 1 2 3 sacred forests and groves sacred water bodies stretch of land adjoining the river or even the agricultural field the sacred forests of maanthaat, hokra devi, danda ka deorana, tarkeshwar, bhujani, bombasing and hariyali devi offer the best example. thamri kund near the township of munsiari; kedar kund within askote conservation landscape latu ka gadera and the small patch of land located in the village pujeli, uttarkashi spawning or mating seasons of species. in uttarakhand, as in rest of the country, many castes abstain totally from consumption of fish, poultry, and meat, and suspend all hunting as well, during the hindu month of ‘sravana’ (roughly august). and thus, temporal taboos function to reduce harvesting pressure on particular subsistence resources (ntiamoa-baidu, 1991). in the present case, temporal taboo extends to periodicity and regulative nature of resource exploitation, primarily from the sacred forests that primarily concerns with the collection of the litter mass (for biocompost purpose), as well as coppicing of the fodder species, which remains the predominant use of the sacred forests by the stakeholders, in the region. however, temporal taboo is less marked overall, except in case of the sacred forests (figure 3), since no exploitation of resources takes place from the sacred groves, borne out of their restricted size and resource availability, thereby rendering them non-economical, both in terms of time and space. in case of the sacred forests, the resource exploitation is primarily on a seasonal basis; in 35 out of the 75 sacred forests covered, followed by complete ban on resource exploitation (in 22 sites, figure 4). sites, where complete ban on resource exploitation is in practice, are the sacred forests, which remain the only watershed and thus the source of water for the resident population, example, the sacred forest of maanthaat. additionally, the harvesting is carried out on an annual basis in few of the sacred forests, which remain the only patch of green and thus the source of fodder for the villagers inhabiting below, example, the sacred forests of chopakya, jagatnath, and jujarimal (table 1 and figure 4). in addition, exploitation of high altitude medicinal and aromatic plants (maps) from the sacred alpine meadows, takes place only once in a year. however, this later temporal taboo could be debated as the maps exploitation are more economical, if the same is carried out at a late stage, when nearly all the maps have attained maturity, example, sacred meadows of bhadelguar, hya roshe, kee pang (all within askote conservation landscape, district pithoragarh). method taboos the method taboo applies when a cultural group bans the use of certain methods and techniques for the withdrawal or exploitation of the species (colding and folke, 2001). invariably in all the cases of sacred forests, this relates to the precise regulation of coppicing of the major fodder species, that is, banj (quercus leucotrichophora), and the collection of the litter mass from the forests. in case of the alpine habitats, principally in case of the sacredbugyals (alpine meadows), this relates to the methodology applied towards managing the grazing pressure, viz., allowing only the yaks and their hybrids (jhuppu and jomos) in case of hya roshe, and only the milching livestocks to graze, in case of the putuk-tu, both within askote conservation landscape. additionally, the van panchayat (village forest council) regularly monitors the grazing pressure and the state of the pasture to make decisions about rotating or relocating herds or even downsizing the size of the grazing herd. yet, other very effective means of lessening the intensity of resource use from the sns are strict adherence to certain norms, viz., partaking measures not to eat meat, drink liquor, even certain completely prohibited eatables, such as onion, garlic (the two most commonly referred abhorred items), for a minimum of one week, before one makes a pilgrimage to sns; the three months prohibitory period extended to each of clan members, when a death occurs in a family; and lastly the phenomenon of restricted days of hunting (table 2). additionally, the method taboo could be extended to the strict norm of walking bare feet, promulgated during the annual jaats (pilgrimage) traversing through the sensitive alpine meadows, viz., during the nanda astamifestival, when sacred brahmkamal (saussurea obvallata) collection is carried out; during chipla kedar jaat or during the more famous nanda devi raj jaat, the devotes traverse the difficult high altitude landscape bare feet. wearing shoes is a taboo. obvious connotation to the significance of the practice towards conservation of the flora could be made, since bare feet are less damaging than the shoes! jagdish et al. 381 n u m b e r o f s a c re d n a tu ra l s it e s 120 100 98 80 60 40 21 20 12 13 8 4 3 1 2 1 1 2 0 class of taboo system1 in practice only segment only temporal only species specific segment + temporal segment + temporal + method temporal + method segment + method method + species specific segment + temporal + method + species specific temporal + species specific temporal + method + species specific segment + species specific figure 3. the preponderance of different classes of taboo system surrounding the sacred natural sites. fo re s ts 40 35 o f s a c re d 30 22 20 18 10 n u m b e r 0 periodic or seasonal once in a year complete ban exploitation pattern figure 4. temporal taboo as regards the exploitation of the resource from the sacred forests (n=75) across the state of uttarakhand. life history taboos the following category of taboos applies when a cultural group bans the use of certain vulnerable stages of a species' life history based on its age, size, sex or reproductive status (colding and folke, 2001). example offered from the landscape, includes the institution of mrigoli (table 1), wherein the hunters do not hunt the pregnant doe, or when they are in a flock. this is more so when one of the deer has a white mark on its forehead (which is more often the case), and the same is treated as reincarnated departed soul, in all probability, of one of the village elders! infact, the hunting is restricted to male and older animals. in this way the communities are able to ensure continued population growth of their wildlife resources. specific-species taboos the following category of taboos applies when a cultural group totally bans the killing and detrimental use of specific species in both time and space (colding and folke, 2001). anthropologists often refer to such taboos as general or permanent food taboos, because they apply to all members in a community and often concern foods (rea, 1981). example offered from the landscape includes the complete ban on killing of fiya (himalayan marmot, marmot bobak) in vyas valley. reasons specified for the behaviour in literature, range from species serving as religious symbols (fargey, 1992), or representing reincarnated humans (osemeobo, 1994). such reasons constitute strong sentiments behind selfenforcement of the taboos. however, in the present case, the taboo is enforced out of the fear that ‘the spirits will sanction violators by invoking illness upon people, or will cause the crop failure’. of particular interest are the taboos imposed on some keystone related plant species, such as deodar (cedrus deodara), paiyan (prunus ceresoides), shiling (osmanthus fragrans), ratpa (rhododendron campanulatum), bil (juniperus communis) and raga (cupressus torulosa), along with the most commonly noted species peepal (ficus religiosa) and bargad (f. benghalensis). it is important to take note of the fact that in invariably all the cases, these species play pivotal role in the conservation or sustenance of the ecosystem, at large. for example, ratpa (rhododendron campanulatum) as well as bil (juniperus communis) provide refuge as well as breeding space for two of the most endangered species, musk deer (moschus chrysogaster chrysogaster) and the monal pheasant (lophophorus impejanus). habitat taboos the following category of taboos applies, when a cultural group regulates both access to and use of resources from particular habitats in space and time (colding and folke, 2001). this taboo, in the present case, obviously extends to each of the sns covered. a forest, part of a forest, a rivulet, or pond may never be subjugated to harvesting, hunting, fishing or any other kind of resource use, often being protected by religious taboos and considered sacred to community members. example from the landscape includes the stretch of land on both the banks of the latu ka gadera, the small rivulet which runs along the sacred grove of latu, near van village, remains a taboo, and hence no agriculture is practiced within the zone. similarly, a small patch of land measuring around 50 by 5 m located within the prime agricultural field in the village pujeli, uttarkashi is not cultivated. these smaller or larger sacred areas, inclusive of all the sns, encompass a number of ecological services, including the maintenance of biological diversity (table 2), provision of habitat for threatened species, regulation of local hydrological cycles, prevention of soil erosion, pollination of crops, 382 afr. j. envir. econ. manage. and preservation of locally adapted crop varieties, and serving as wind and fire brakes (gadgil, 1987). one of the prime examples is offered by the sacred forest site, the thamri kund, where one can easily sight the herd of serow (cervus unicolor), as well as other wild animals, who come to drink the water at the site. this little lake located at a height of around 3000 m amsl, is held very sacred, not just by the locals of the surrounding villages, but by the populace of the adjoining township of munsiari. as per one locals, ‘no one is allowed to defile the waters, not even drink directly from it!’ in summary, as and when the above-mentioned class of taboos is transgressed, an expiation ceremony has got to be undergone. a breach of the law would bring on the entire society divine wrath. invariably, however, the social taboos need enforcement mechanisms to be effective (north, 1990). the informal institutions like social taboos are self-enforced by the community (north, 1990; posner and rasmusen, 1999), the self-enforcement being principally borne out of the fear of religious sanctions and social conventions (osemeobo, 1994). the precise monitoring of compliance of norms surrounding the resource use from the sacred natural sites, and else, is furthermore facilitated due to the closeness of family members and strong kinship ties (north, 1990). furthermore, sanctions against violations of taboos may be determined and meted out by chiefs and leaders. such sanctions include monetary fines, payment in cattle (ntiamoabaidu, 1991), or even ‘sacrificing a goat or a sheep’, as is the usual case in most of the sacred sites encountered. this charge is sufficiently deterrent to scare people from infringing or breaking the taboos. conclusion the institution of sacred natural sites, along with the strict norms and taboos that relates to resource utilization, invariably relates to the sustainable resource management practices (dorm et al., 1991; hagan, 1998). temporal taboos, and perhaps segment taboos, may promote local conservation of subsistence resources. in summary, taboos contribute to the conservation of habitats, and of biodiversity, both temporally and spatially, as is explicit from tables 1 and 2. however, a much clearer under-standing of spiritual and mystical beliefs, and the related local institutions associated with traditional natural resources management, is needed. such an assessment would provide valuable insights into the changing values of local people in relation to the protection of forests and other natural resources. collaborative research involving anthropologists and natural scientists may help explain the scientific and social value of beliefs related to traditional natural resources management in the study area. this may enhance the acceptability of these traditions, many of which have conservation potential. needless to jagdish et al. 383 emphasize, there is an urgent need to set forth specific guidelines to safeguard the sacred areas and promote the traditional knowledge of conservation, namely: the revitalization and enforcement of traditional education; the delineation of boundaries; the improvement of relevant knowledge and their official recognition through a legal status (dorm-adzobu and ampadu-agyei, 1995; mcwilliam, 2001). it is urgently felt that traditional knowledge-based systems that is, the local belief systems should be made inclusive part of developmental programmes, for the simple reason that the local populace could relate themselves to the same. acknowledgements the author gratefully acknowledges the financial help received from the director, uttarakhand state council for science and technology, government of uttarakhand, dehradun, and the director, g. b. pant institute of himalayan environment and development, kosikatarmal, almora. the study however, would not have been possible without the help of the village residents-the ultimate custodians of the biodiversity. references abayie ba (1998). traditional conservation practices: ghana's example. inst. afr. stud. res. rev., 14(1): 42-51. colding j, folke c (2001). social taboos: ‘invisible’ systems of local resource management and biological conservation. ecol. appl., 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1: 69-83. ross eb (1978). food taboos, diet, and hunting strategy: the adaptation to animals in amazon cultural ecology. curr. anthro., 19:136. sinclair fl, walker dh (1999). a utilitarian approach to the incorporation of local knowledge in agroforestry research and extension. in buck le, lassoie jp, fernandes ecm (eds) agroforestry in sustainable agricultural systems, crc press llc, boca raton, fl, usa, pp. 245-275. in ternationa l scholars journa ls african journal of environmental economics and management issn 2375-0707 vol. 3 (5), pp. 244-248, october, 2015. available online at www.internationalscholarsjournals.org © international scholars journals author(s) retain the copyright of this article. full length research paper a study of metabolism of para-nitrophenol in arthrobacter sp. spg akash mukul jyothi department of environmental sciences, school of life sciences, university of hyderabad, p.o central university, hyderabad-500 046. email : akash_jyothi@gmail.com accepted 22 april, 2014 arthrobacter sp. spg utilized p-nitrophenol (pnp) as the sole carbon, nitrogen, and energy source. the stoichiometric amounts of nitrite ions were released from pnp. the pathway of pnp degradation was studied for strain spg. on the basis of thin layer chromatography, high performance liquid chromatography and gas chromatography-mass spectrometry, hydroquinone (hq) was identified as major intermediate product. hq dioxygenase activity was found in crude extract of pnp induced cells of strain spg that suggested the cleavage of hq into gamma-hydroxymuconic semialdehyde. this study clearly showed that strain spg degraded pnp via hq pathway. arthrobacter sp. spg degrades various nitroaromatic compounds including pnp, 2-chloro-4nitrophenol, 3-methyl-4-nitrophenol, 2-nitrocatechol and 2-nitrobenzoate. this strain would be a suitable candidate for bioremediation of nitroaromatic compounds contaminated sites. keywords: arthrobacter sp. spg, biodegradation, bioremediation, hydroquinone, metabolism, p-nitrophenol, nitroaromatic compounds, sole carbon and energy source introduction p-nitrophenol (pnp) is an environmental pollutant that is used for the manufacturing of dyes, explosives, pesticides, herbicides and drugs (spain, 1995). it is also a hydrolytic product of the pesticide parathion (munnecke and hsieh, 1974). it may cause a blood disorder that reduces the ability of the blood to carry oxygen to tissues and organs due to methemoglobinemia (atsdr, 1992). it is a potent uncouple of oxidative and photosynthetic phosphorylation. further, it is also considered as mutagen (cooper et al., 1997). due to its high toxicity, united state environmental protection agency (usepa) has listed it as a priority pollutant. bacteria that use pnp as sole carbon and energy source have been isolated and characterized (mitra and vaidyanathan, 1984; hanne et al., 1993; spain, 1995; wan et al., 2007). aerobic degradation of pnp was occurred either formation of hydroquinone (spain and gibson, 1991) or formation of nitrocatechol (kadiyala and spain, 1998). previously, it has been supposed that gram-positive bacteria degrade pnp via nitrocatechol pathway whereas gram-negative utilize pnp via hydroquinone pathway. literature studies showed that both gram-positive and gram negative bacteria can degrade pnp either via hydroquinone pathway or via nitrocatechol pathway (jain et al., 1994; hanne et al., 1993; spain, 1995; pakala et al., 2006; chauhan et al., 2007). in this communication, we reported the degradation of pnp via hydroquinone pathway by arthrobacter sp. spg materials and methods isolation of a pnp degrading bacterium strain spg was isolated from the soil collected from a pesticide contaminated site, india by enrichment method using 4np as a substrate. strain spg utilized pnp as sole carbon and energy source. strain spg was screened to find out its degradation capacity for various jyothi 244 nitroaromatic compounds. for screening, strain spg was streaked on minimal agar plates containing 0.3 mm test compound as sole carbon and energy source. minimal agar plates were prepared by dissolving the followingcompounds in 100 ml of double distilled water: 0.4 g na2hpo4, 0.2 g kh2po4, 0.08 g (nh4)2so4, 0.08 g mgso4.7h2o, 0.1 ml trace element solution and 1.8 g agar. the composition of trace element solution was exactly same as described previously (arora and jain, 2011a). the media was autoclaved at 15 lbs for 20 min. after autoclave, the desired concentration (0.3 mm) of the filter sterilized test compound was added to the media and media was allowed to cool at room temperature and poured into petri plates. 2-nitrophenol, 2-chloro-4nitrophenol, 3-methyl-4-nitrophenol, 3-nitrophenol, 2amino-4-nitrophenol, 4-nitrocatechol and 2-nitrobenzoate were used as test compounds. decolourization and/or growth of strain spg on minimal agar plates was/were considered as positive results. uv radiation and sprayed with folin-ciocalteu’s reagent. hplc analysis was carried out using a waters 600 model high performance liquid chromatography (hplc) equipped with a photodiode array detector system. the compounds were separated on a c18 reverse-phase silica column using 1% glacial acetic acid in methanol and 1% glacial acetic acid in hplc grade water at a ratio of 80:20 as the mobile phase. flow rate was 1.0 ml/min; injection volume was 15 µl, and the compounds were detected at 280 nm and 300 nm. gc-ms analysis was carried out using a gc-msqp5000 instrument (shimadzu, tokyo, japan) equipped with quadrupole mass filter and db-1 capillary column with ionization of 70 ev, scan interval 1.5 s and mass range of 50-550 da. the column temperature was initially increased from 90°c to 180°c at the rate of 5°c/min and then from 180°c to 280°c at the rate of 10°c/min. the carrier gas (nitrogen) flow rate was 10 ml/min. identification of bacteria strain spg was identified by the 16s rrna gene sequencing using the universal primers as described previously (arora et al., 2011). growth of strain spg on pnp strain spg was grown on 1l erlenmeyer flask containing 250 ml minimal media and 0.3 mm pnp as sole carbon and energy source. the flask was incubated at 30°c under shaking condition at 200 rpm. samples were collected at regular intervals and growth of microorganism was measured by taking optical density at 600 nm. for estimation of nitrite release, samples were centrifuged at 8000 rpm and supernatant was used for nitrite detection by classical method (spain and gibson, 1991). identification of metabolites samples collected at different intervals were centrifuged and supernatants were extracted with ethyl acetate. extracted samples were analyzed by thin layer chromatography (tlc), high performance liquid chromatography (hplc) and gas chromatography-mass spectrometry (gc-ms). tlc was performed using pre-coated silica gel 60 f254 plates (20 x 20 cm, 0.25 mm; merck, germany) with solvent (toluene: ethyl acetate: glacial acetic acid, 60:30:5). the compound(s) was/were visualized under crude extract preparation strain spg was grown on 200 ml minimal media, 10 mm sodium succinate and 0.3 mm pnp. cells of strain spg were centrifuged just prior to decolourization and washed twice with phosphate buffer (20 mm, 7.4 ph) and resuspended in the same buffer. the cells were sonicated in a sonicator by twenty 30s burst with intermittent 30s cooling on ice. the cell extracts were centrifuged (12000 rpm) at 4°c for 15 minutes to remove cell debris and the supernatant was used for enzyme assay. protein contents were estimated according bradford method (bradford, 1976). enzyme assay hydroquinone dioxygenase activity was determined by measuring decreased the absorbance of substrate at 289 nm and increased the absorbance of product at 320 nm. the reaction mixure contanined ( in a final volume of 1ml) 20 mm phosphate buffer, 0.1 mm hydroquinone, 0.1 mm ferrus sulphate and 0.5-1.0 mg crude extract of the proteins. results isolation and identification of strain spg a pnp degrading bacterium, strain spg was isolated from a pesticide contaminated site, india and utilized following compounds as sole carbon and energy source: pnp, 2-chloro-4-nitrophenol (2c4np), 2-nitrobenzoate, 3methyl-4-nitrophenol and nitrocatechol strain spg was 245 afr. j. environ. econ. manage. figure 1. (a) growth of the strain spg on pnp and depletion of the pnp by strain spg. (b) stoichiometric release of nitrite ions when strain spg grown on minimal salt media and 0.3mm pnp and non-stoichiometric release of nitrite ions when strain spg grown on nitrogen free minimal media and 0.3mm pnp. figure 2.tlc analysis of samples of pnp degradation by arthrobacter sp. spg. tlc showing the presence of hydroquinone in blue colour spots after spraying with folin-ciocalteu’s reagent. identified as arthrobacter sp. on the basis of the 16s rrna gene sequencing. the 16s rrna gene sequence of strain spg has been deposited in the growth of strain spg on pnp: when strain spg was grown on minimal media containing 0.3 mm pnp as sole carbon and energy source, the yellow color of pnp (0.3 mm final concentration) changed to colourless indicating its utilization by the microorganism. microbial growth was measured by the increased in optical density (od) at 600 nm and depletion of pnp was measured by taking the od at 420 nm (figure. 1a). the microorganism released nitrite ions in the medium, suggesting the involvement of an initial oxidative step in the degradation of pnp. the stoichiometric amounts of nitrite ions was observed when strain spg was grown on minimal media containing pnp as sole carbon and energy source. when strain spg was grown on nitrogen free minimal media (without genbank database under the accession number hm027882.ammonium sulphate) containing 0.3 mm pnp, non-stoichiometric release of nitrite ions was observed (figure. 1b). this is due to the rapid utilization of nitrite ions as a nitrogen source in the absence of ammonium sulphate. this data suggested that strain spg utilize pnp as sole carbon, nitrogen and energy source. metabolic pathway for pnp degradation: tlc analysis indicated the presence of hq (rf 0.65) and pnp (rf 0.75) in samples drawn from 8 and 12 h intervals. however, the samples drawn after 16 hours growth did not show the presence of pnp or another intermediate indicating the whole degradation of pnp. furthermore, when tlc plates were sprayed with folinciocalteu’s reagent an immediate blue coloration was apparent in case of suspected hq spot since dihydroxylated benzene gives an immediate blue coloration with this reagent (figure 2). hplc analysis also showed the presence of hq along with pnp in the samples drawn from 8 and 12 h period (figure. 3). jyothi 246 figure 3. hplc analysis of samples showing degradation of pnp by arthrobacter sp. spg with appearance of intermediate hydroquninone. figure 4. mass fragement of metabolite hydroquinone. however, no pnp or hq peaks were observed in 16 h drawn samples, again suggesting the whole degradation of pnp. gc-ms analysis was also carried out to confirm the presence of hq in the degradation pathway of pnp. gc-ms(figure 4). showed that mass fragment of the metabolite was observed at 110 m/z that was exactly matching that of the standard hq (figure. 3). inhibition studies were also carried out using 2,2'-dipyridyl since the presence of this compound in the growth mediumchelates ferrous ions required for the ring-cleavage of aromatic compounds. strain spg was grown on minimal media containing pnp, sodium succinate and 2,2'-dipyridyl and samples were taken at regular interval and extracted with ethyl acetate and extracted samples were analyzed by tlc and hplc. results of this experiment showed that there was accumulation of hq even after 48 h of growth, . oh o oh cooh cho no2 o oh oh 4-nitrophenol 1,4-benzaquinone hydroqionone γ−hydroxymuconic semialdehyde figure 5. proposed pathway of pnp degradation by arthrobacter sp. spg suggesting the inhibition of the ring cleavage of hq (data not shown). to identify the ring cleavage product, enzyme assay for hq dioxygenase activity was carried out. the spectrophotometric analysis of hq dioxygenase assay showed that the peak of the hq at289 nm disappeared gradually and a transient peak of 4hydroxymuconic semialdehyde around 320 nm appeared. discussion arthrobacter sp. spg is a versatile bacterium that able to degrade various nitroaromatic compound including pnp, 2c4np, 3-methyl-4-nitrophenol, nitrocatechol and 2nitrobenzoate. this strain would be a suitable candidate for bioremediation of a nitroaromatic contamitaned site. several members of the genus arthrobacter are known to degrade phenolic compounds. arthrobacter chlorophonolicus a6 was characterized to degrade mixture of phenol, pnp and 4-cholrophenol (westerberg et al., 2000). arthrobacter ureafaciens cpr706 has been reported to degrade 4-chlorophenol via hq pathway (bae et al., 1996). the degradation of phenol by immobilized cells of arthrobacter citrus has also been achieved (karigar et al., 2006). arthrobacter sp. sjcon utilized 2chloro-4-nitrophenol as the sole carbon and energy source (arora and jain, 2011b). furthermore, arthrobacter protophormiae rkj 100 (chauhan et al, 2007), arthrobacter sp. js443 (jain et al., 1994), and arthrobacter aurescens tw17 (hanne et al., 1993) have been reported to degrade pnp. this study also report degradation of pnp by arthrobacter sp. spg. the members of genus arthrobacter degrade pnp either by hq pathway (jain et al., 1994) or nitrocatechol pathway (chauhan et al., 2007). in nitrocatechol pathway, pnp was converted to nitrocatechol by monooxygenation at ortho position. nitrocatechol was further converted to 1,2,4benzentriol (bt) by monooxygenation at para position with release of nitrite ions (chauhan et al., 2007). bt then cleaved into maleylacetate by ring cleavage activity of bt dioxygenase (chauhan et al., 2007). in hq pathway, pnp was first converted to 1,4-benzoquinone (bq) by a monooxygenase and bq was further reduced to hydroquinone (hq) that was further cleaved to gammahydroxymuconic semaldehyde by hq dioxygenase (jain et al., 1994). this study clearly showed that arthrobacter sp. spg degraded pnp via hq pathway (figure. 5). conclusion a pnp degrading bacterium arthrobacter sp. spg was isolated from soil collected from a pesticide contaminated site. strain spg utilized pnp as sole carbon, nitrogen and energy source and degraded it via formation of hq. strain spg was also able to degrade 2-chloro-4nitrophenol (2c4np), 2-nitrobenzoate, 3-methyl-4nitrophenol and nitrocatechol. this strain may be used for bioremediation of nitroaromatic compounds contaminated sites. acknowledgements author is thankful to the university grants commission, new delhi for financial supports. references arora pk, chauhan a, pant b, korpole s, mayilraj s, jain rk (2011). description of chryseomicrobium imtechense gen. nov., sp. nov., a new member of the family planococcaceae. int j sys evol microbiol 61:1859–1864. arora p k, jain rk (2011a). biotransformation of 4-chloro-2-nitrophenol into 5-chloro-2. methylbenzoxazole by a marine bacillus sp. strain mw-1. biodegradation., doi: 10.1007/s10532-011-9512-y. arora pk, jain rk (2011b). pathway for degradation of 4-chloro-2nitrophenol by arthrobacter sp. sjcon. curr microbiol, 63:568-573. atsdr (1992). 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biodegradation of methyl parathion and p-nitrophenol: evidence for the presence of a p-nitrophenol 2hydroxylase in a gram-negative serratia sp. strain ds001. appl microbiol biotechnol, 73:1452-62. spain jc, gibson dt (1991). pathway for biodegradation of pnitrophenol in moraxella sp. appl. environ. microbiol, 57:812-819. spain jc (1995). biodegradation of nitroaromatic compounds. annu rev microbiol, 49: 523-555. westerberg k, elväng am, stackebrandt e, jansson jk (2000). arthrobacter chlorophenolicus sp. nov., a new species capable of degrading high concentrations of 4-chlorophenol. int j syst evol microbiol, 6:2083-2092. yamamoto k, nishimura m, kato d, takeo m, negoro s (2011). identification and characterization of another 4-nitrophenol degradation gene cluster, nps, in rhodococcus sp. strain pn1. j biosci bioeng, 111:687-94. 1 in ternationa l scholars journa ls african journal of environmental economics and management issn 2375-0707 vol. 9 (2), pp. 001-009, february, 2021. available online at www.internationalscholarsjournals.org © international scholars journals author(s) retain the copyright of this article. full length research paper removal of faecal bacteria and nutrients from domestic wastewater in a horizontal surface flow wetland vegetated with echinochloa pyramidalis lekeufack martin1, fonkou théophile1*, pamo tedonkeng etienne2 and amougou akoa3 1 laboratory of applied botany, university of dschang, cameroon. 2 department of animal production, faculty of agronomy, university of dschang, cameroon. 3 department of plant biology, faculty of science, university of yaoundé i, cameroon. accepted 24 july, 2020 the aim of this study was to evaluate the removal of faecal bacteria and nutrients from domestic wastewater, in surface flow wetlands vegetated with echinochloa pyramidalis. horizontal surface flow (hsf) wetlands were fed with primarily treated domestic wastewater at organic loading rates varying from 20.74 to 27.15 g bod/m 2 /day for two consecutive years. water samples were collected at two weeks interval from the inflow and the outflow of the treatment wetlands for physicochemical and faecal bacteria analyses. physicochemical parameters with highest removal rates were total suspended solids (tss, 62-80%), nitrates (57-73 %) and po4 -3 (57-84 %). faecal indicators reductions of 1.4 and 0.3 log units (1 st year) and 1.15 and 0.65 log units (2 nd year) were respectively recorded in the vegetated and the control wetlands. reductions of total coliforms, faecal coliforms and faecal streptococci were significantly higher in the vegetated wetland than in the non-vegetated control in both seasons of the first year. in the contrary, there was no significant difference in the removal rates of faecal indicators between vegetated wetland and the non-vegetated control during the dry season of the second year. wetlands vegetated with e. pyramidalis was proven to be continuously efficient in the removal of faecal indicators for the two years of study, with no significant differences between the seasons of the year and between the years. key words: wastewater, wetlands, echinochloa pyramidalis, faecal bacteria removal, nutrients removal. introduction constructed wetlands (cws) have been used as promising wastewater treatment alternatives to the more expensive conventional systems, especially in developing countries (kivaisi, 2001; song et al., 2006). they produce high quality effluent at low investment cost, simple operation and with very low energy dissipation (ayaz and akca, 2001). they therefore help greatly to reduce the health hazards associated with the waste disposal methods in most developing countries (gilbert et al., 1976; mburu et al., 2008). studies on constructed *corresponding author. e-mail: tfonkou@yahoo.fr. tel: +237 77570991. wetland systems vegetated with macrophytes have shown that the percentage reductions of physicochemical parameters are generally high especially in tropical zones, where climatic conditions are able to sustain vegetation all the year round. research works in the recent years have been focused on the ability of macrophytes based constructed wetlands to reduce oxygen demands and nutrients such as nitrates and phosphates (kengne et al., 2009a; fonkou et al., 2010). meanwhile, the removal of faecal contaminants indicators from domestic wastewater has not gained much concern. several studies reporting on microbial water quality improvement have shown that constructed wetlands reduce microorganism populations in wastewater at varying but significant degree of effectiveness (paluszak 2 figure 1. the yard-scale setup of the experiment station. et al., 2003; keffala and ghrabi, 2005; song et al., 2006; mburu et al., 2008; reinoso et al., 2008). song et al., (2006) reported 99.7% reduction of faecal coliforms in asia, paluszak et al. (2003) and reinoso et al. (2008) respectively reported the removals of 99 and 96% for escherichia coli and faecal streptococci in europe while keffala and ghrabi (2005) and mburu et al. (2008) also respectively reported removals of 90 and 99.9 for faecal coliforms in africa. the removal mechanisms of these bacteria are numerous. these include predation, natural die off, ultra violet radiations on the cell wall of bacteria, oxygen leakages from the roots of macrophytes, bactericidal substances secreted by roots as well as the antibiotic properties of some bacteria living in the rhizosphere (green et al., 1997; song et al., 2008). in cameroon, many studies have been published on echinochloa pyramidalis as concerns its biomass production in constructed wetlands, its ability in faecal sludge dewatering improvement and biosolids recovery, its response to salinity stress, its nutritional potentials and also its presence in natural wetlands especially the polluted ones (kengne et al., 2009a, b; fonkou et al., 2010; pare et al., 2011a, b; lekeufack et al., 2011). but there has been no concern on its ability to reduce bioindicators of faecal contamination from wastewater, despite the continuous report of a water related diseases in developing countries. the aim of this study was to evaluate domestic wastewater quality improvement in a horizontal surface flow (hsf) wetland configuration vegetated with e. pyramidalis. the removal efficiencies of faecal coliforms, faecal streptococci and total coliforms as well as some physicochemical parameters were measured in the wetland vegetated with e. pyramidalis and in the non vegetated control wetland for two consecutive years. material and methods this study was conducted in a constructed wetland system in the campus of the university of dschang, located between latitudes 5°25’ and 5°30’ north and between longitudes 10°00’ and 10°5’ east in the western highlands of cameroon. the climate in this region is of equatorial type with two seasons: 4 months of dry season from mid-november to mid-march, and 8 months of rainy season from mid-march to mid-november. annual precipitations range between 1433 and 2137 mm, while annual mean temperature is estimated at 20.8°c with thermal amplitude of 2°c (anonymous data from the local meteorological station, 1978-2008). wastewater used in the study was collected from a small primary treatment plant receiving domestic liquid wastes from the students’ residence at an inflow rate of 3 m 3 per day. part of the primarily treated wastewater was channelled into a 1.3 m 3 gutter from where it was distributed to the experimental wetlands using pvc pipes. design of the experimental wetlands five wetlands of 3 × 1 × 0.6 m 3 were constructed using cement blocks (figure 1). the inside of the structures were plastered with concrete, then cement and lankofuge tm for water tightness. a 1% slope was constructed on the bottom of each wetland bed to ease the movement of water from the inlet to the outlet. gabions of 30 cm with stones of 5-8 cm in diameter were arranged at the inlet and outlet zones of the wetlands, while a drainage layer of about 10 cm was arranged at the bottom. the outlet structures were adjustable to enable the regulation of the water level in the substrate. 3 figure 2. longitudinal section of the experimental wetland. cw3 cw1 figure 3. aspect of the vegetation in the wetland at the start of the analysis in the first year. the main filter substrate was a 40 cm column of sand having particles size < 2 mm (figure 2). results presented on this paper are those of cw1, that was vegetated with e. pyramidalis and cw3 that was used as the non vegetated control wetlands. the inflow rate was estimated at 205 litres/day. the bed capacity measured from the porosities of the gabion and the sand filter was 923 litres. the hydraulic retention time (hrt) of 4.5 days was then calculated from the equation: = as stated by lorion et al. (2001). the constructed wetlands serve as a secondary treatment associated to the existing primary treatment in which only the particle filter and the digester were still functioning. setting up the experiment young shoots of e. pyramidalis were collected from a natural wetland and washed in fresh water. after weighing, shoots were planted in cw1 at a density of 14 shoots/m 2 . primarily treated effluent from a conventional treatment plant was collected in a gutter and allowed to directly flow into the wetlands at organic loading rates varying from 20.74 to 27.15 g bod/m 2 /day in dry season and the rainy season of two consecutive years. macrophyte shoots were domesticated in the wetland for one month during which they grew and had standing vegetation considered to have good biological activity (figure 3). the wastewater was then allowed to flow constantly into each bed at a loading rate of 85.43 l m -2 day -1 in a horizontal surface flow (hsf) configuration for two consecutive years. at the end of every season, the plants were harvested after they have flowered. sample collection and microbiological analyses water samples were collected at two weeks interval throughout the research period at the inflow and the outflow of the treatment wetlands, from december 2009 to october 2011. 500 ml of each were kept in sterile laboratory glass bottles and transported in a cooler to the laboratory where they were immediately analyzed. in the laboratory, manipulations were carried out in strict conditions of sterility. in aseptic conditions, 1 ml of homogenous raw sample was measured and added into 9 ml of sterile distilled water to have 1:10 dilution. this same operation was repeated from the first dilution until the desired dilution was obtained (1:10, 1:100, 1:1000, 1:10 000, etc). the pipette was always rinsed between dilutions to avoid contamination. the distilled water was sterilized by autoclaving in sealed sterile glass bottles for 15 min at 121°c. total coliforms, faecal coliforms and faecal streptococci were detected by the membrane filtration following standard methods (apha, 1998; ceae, 2005). ac cellulose membranes filters tm with pore-size 0.45 µm were used on a wheaton filtering funnel tm attached to a cm 1500 vacuum pump tm . appropriate sample volumes, in three different dilutions (10 -2 , 10 3 and 10 -4 ) for effluent or (10 -3 , 10 -4 and 10 -5 ) for influent were filtered and incubated for each parameter. this was to ensure having at least a plate with colony counts ranging between 20 to 100 cfu (hench et al., 2003). samples for faecal coliforms were incubated on difco tm mfc prepared agar in petri dishes at 44.5°c for 24 h (karathanasis et al., 2003). thereafter, all characteristically blue and central white hollowed blue colonies were counted as faecal coliforms. samples for faecal streptococci and total coliforms were respectively incubated on bbl tm bile esculin and tergitol ® 7 agars at 35°c for 48 h (karathanasis et al., 2003). thereafter all characteristically black and yellow colonies were respectively 4 table 1. average counts (log10 units cfu/100 ml) of faecal contaminant indicators (total coliforms, tc; faecal coliforms, fc; and faecal streptococci, fs) in the inflow and outflow of the vegetated and the control wetlands during the dry and rainy seasons of the first year. dry season rainy season parameter inflow outflow outflow inflow outflow outflow vegetated control vegetated control t.c. 7,36±0,22 6,10±0,43 7,18±0,39 7,48±0,27 6,36±0,28 7,10±0,25 f.c. 7,27±0,34 5,21±1,55 6,77±0,41 7,57±0,35 6,25±0,73 7,34±0,47 f.s. 7,76±0,43 6,32±1,60 7,51±0,45 7,38±0,56 6,37±0,76 7,25±0,62 figure 4. percentage removals of faecal indicators in the vegetated and in the control wetlands in the dry season (a) and rainy season (b) of the first year. counted for faecal streptococci and total coliforms. each result was expressed as number of colony forming units per 100 ml (cfu/100ml) of sample. measurement of physicochemical parameters the physicochemical parameters including total suspended solids (tss), nitrates, orthophosphates, chemical oxygen demand (cod), and 5-days biochemical oxygen demand (bod5) were measured according to procedures described by hach (2004). statistical analyses the analysis of variance anova in prism.4 software at 0.05% probability level was used to test parameter differences between the inlet and the oulets of the wetlands. means were then separated using newman-keuls multiple comparison test under windows (fonkou et al., 2010). as concerns microbial population density, data were log10 transformed to obtain the geometric means. results removal of faecal bacteria table 1 presents mean microbial densities in the inflow and outflows of the wetland during the first year of monitoring. the mean concentrations of faecal indicators varied generally from 7.3 to 7.8 log units at the inflow, 6.8 to 7.5 and 5.2 to 6.4 log units respectively at the outflows of the control and vegetated wetlands. compared with the inlet, average reductions of 1.6 and 0.35 log units were respectively observed at the outlets of the vegetated and non vegetated control wetlands during the dry season and 1.2 and 0.27 log units during the rainy season. these corresponded to percentage removals ranging from 87 to 95% and from 24 to 71% respectively. from statistical analyses, the concentrations of faecal bacteria at the outflow of the vegetated wetland were in general significantly different (p˂0.05) from the outflow in both seasons. the most reduced parameter in the vegetated wetland was faecal coliforms in both seasons, while least reduced was faecal streptococci. in the control wetland, the most reduced parameter in both seasons was total coliforms and faecal streptococci were still the least reduced. figure 4 presents the mean removal rates of faecal contaminant indicators in the wetlands during the first year. removal efficiencies ranging from 88 to 95% in the vegetated wetland and from 26 to 71% in the control were recorded in the dry season. during the rainy season, 86 to 92% and 24 to 51% removal rates were recorded in the vegetated and control wetlands 5 table 2. average counts (log10 units cfu/100 ml) of faecal contaminant indicators (total coliforms, tc; faecal coliforms, fc; and faecal streptococci, fs) in the inflow and outflow of the vegetated and the control wetlands during the dry and rainy seasons of the second year. dry season rainy season parameter inflow outflow outflow inflow outflow outflow vegetated control vegetated control t.c 7,65±0,44 6,59±0,55 7,05±0,26 7,60±0,27 7,08±0,31 7,14±0,38 f.c 7,50±0,65 6,35±0,44 6,94±0,54 7,50±0,65 6,32±0,90 6,81±0,99 f.s 8,00±0,38 6,89±0,77 7,59±0,45 8,19±0,35 6,74±0,55 7,41±0,67 figure 5. percentage removals of faecal indicators in the vegetated and control wetlands in the dry season (a) and rainy season (b) of the second year. respectively. the wetlands were all more efficient in the dry season than in the rainy season, but there was no significant difference between the seasons. in this year, the outflow of all the wetlands were significantly different from the inflow for all the parameters, but the outflow of the vegetated wetland was significantly more efficient (p˂0.05) than that of the control in the removal of total coliforms in the dry season, and all the three parameters in the rainy season. the outflow of the control wetland was not different from the inflow (p˃0.05) in the rainy season for faecal coliforms and faecal streptococci. in the second year, the mean concentrations of faecal indicators at the outflows of the wetlands ranged generally from 5.6 to 7.1 and 6.0 to 7.6 log units in the vegetated and non vegetated control wetlands respectively (table 2). this gives average removal efficiencies of 1.2 and 0.6 log units at outflows of planted and non vegetated control wetlands respectively in the dry season, and 1.09 and 0.69 log units respectively in the rainy season. the most reduced parameter in the planted bed during the second year was faecal coliforms in the dry season and total coliforms in the rainy season. the least reduced parameter was faecal streptococci in both seasons. in the non vegetated control the most reduced parameter was faecal coliforms in both seasons and the least reduced was faecal streptococci. figure 5 presents the average percentage removals of faecal contaminants indicators in the wetlands during the second year. removal efficiencies ranging from 81 to 91% in the vegetated wetland and from 55 to 63% at in the control were recorded in the dry season. in the rainy season, 66 to 92% and 55 to 71% were recorded in the vegetated and non vegetated control wetlands respectively. statistical analysis revealed no significant differences between the two wetlands, although the outflows were always significantly different from the inflows. the removals of faecal coliforms and faecal streptococci in the vegetated wetland during the dry season were significantly higher than those recorded in the non vegetated control. the wetlands seemed more efficient in the dry season than in the rainy season but the difference between the two seasons was not significant (p˃0.05). the vegetated and the control wetlands also seemed more efficient in the removal of faecal indicators in the first year than in the second year, even though there was statistically no significant difference (p˃0.05) between the two years. reduction rates of physicochemical parameters figure 6 presents the removal efficiencies of the treatment beds during the first year as calculated from 6 figure 6. percentage reductions of physicochemical parameters in the vegetated and control wetlands in the dry season (a) and rainy season (b) during the first year (cnd, conductivity; tss, total suspended solids). table 3. average physicochemical characteristics of water at the inflow and outflow of the wetlands during the dry and the rainy seasons of the first year dry season rainy season parameter inflow outflow outflow inflow outflow outflow vegetated control vegetated control cnd (µs/cm) 3815±288 3440±239 3344±295 1880±322 1694±309 1467±221 tss (mg/l) 399±72 103±14 104±15 1513±676 56±11 100±19 turbidity (ftu) 437±71 198±17 176±26 464±89 80±22 105±30 colour (ptco) 1533±186 911±85 803±93 1049±184 386±107 348±68 no3 (mg/l) 55±24 35±18 48±18 5±1 1.8±0.39 2.26±0.64 po4 -3 (mg/l) 186±43 133±49 150±31 69±22 31±15 34±11 cod (mg/l) 702±63 360±42 376±44 788±97 288±37 496±59 bod (mg/l) 219±38 112±16 130±20 317±28 120±9 206±23 figure 7. percentage removals of physicochemical parameters in the vegetated and control wetlands in the dry season (a) and rainy season (b) of the second year (cnd, conductivity; tss, total suspended solids). the data presented in table 3. the tss was the parameter with the highest reduction rate in the vegetated wetland during the dry season (62%) and during the rainy season (92%). percentage reduction of 58% was recorded for nitrates during the dry season and 57% for phosphates in the rainy season. throughout this first year, conductivity and tss had higher reduction rates in the non vegetated control than in the vegetated wetland, but there was no significant difference between the two wetlands (p˃0.05). the vegetated wetland had higher removal efficiencies for nitrates and phosphates than the non vegetated control in both seasons. during the second year, nutrients with the highest removal rate (84%) in the vegetated wetland were phosphates, while nitrates were reduced at 73% in the rainy season. tss in this bed was respectively reduced at 68 and 80% in the dry season and rainy season (figure 7). the highest reduction rates in the control wetland were 7 table 4. average physicochemical characteristics of water at the inflow and outflow of the wetlands during the dry and the rainy seasons of the second year. dry season rainy season parameter inflow outflow outflow inflow outflow outflow vegetated control vegetated control cnd (µs/cm) 3705±383 3311±427 3183±383 2293±354 1936±316 1414±259 tss (mg/l) 584±90 151±21 117±38 616±120 83±6.2 86±15 turbidity (ftu) 265±29 100±14 60±12 311±71 58±4.02 65±21 colour (ptco) 696±62 372±73 232±47 424±58 213±22 149±21 no3 (mg/l) 8±1.95 4±0.6 4,19±0.64 5±1 1,33±0.39 2,52±0.42 po4 -3 (mg/l) 112±18 17±3 33±4 94±32 30±5 29±6 cod (mg/l) 545±10 278±15 429±30 582±21 213±27 426±43 bod (mg/l) 229±4 117±6 164±22 244±9 90±11 173±20 recorded for tss (76%) and (78%) in the dry and rainy seasons respectively. conductivity had the least reduction (11%) in the dry season while nitrates had the least reduction (26%) in the rainy season. the vegetated wetland was significantly more efficient (p˂0.05) than the non-vegetated control in the removal of nitrates in this rainy season. bod and cod removals rates during the dry season of the first year (44 and 42% respectively) were lower but not significantly different from those recorded in the rainy season (55 and 57%). this trend was not respected in the second year, since the reduction rate of 49% recorded for cod and bod during the dry season was low and significantly different from the 64% (bod) and 63% (cod) obtained in the rainy season. it is noticed that the reduction of oxygen demands was always ˂ 50% in the dry seasons and always ˃ 50% in the rainy seasons. as indicated in tables 3 and 4, the quality of the water in the outflow of the wetlands was still very poor, even though high percentage reductions of several parameters were observed. discussion the reductions of 1.4 and 0.3 log units observed in the vegetated and control wetlands respectively in the first year are similar to those observed by karathanasis et al. (2003) and torrens et al. (2009) in polycultured systems. these results are also found within the range of removals reported for constructed wetlands treating domestic wastewater in similar conditions (greenway, 2005; morsy et al., 2007; reinoso et al., 2008). the wetland vegetated with e. pyramidalis was significantly more efficient (p˂0.05) than the non vegetated control in the reduction of parameters such as total coliforms in the dry season and all the three parameters in the rainy season. these differences may explain the role played by plants roots in the substratum-root matrix, and the difference in substrate’s microbial composition due to presence of plants as the wastewater passes through. kaseva (2004) emitted a similar reasoning when he found that his vegetated systems were more efficient than the non vegetated control. the results of the present research are different from those reported by mburu et al. (2008) where the non vegetated control bed was in the average more efficient than the vegetated wetland in a subsurface horizontal flow system. the high but non significant removals of faecal indicators in the non vegetated control in the dry season of the first year could also be attributed to the various physical, chemical and biological mechanisms for bacterial removal in constructed wetlands (williams et al., 1995; green et al., 1997; stevik et al., 2004). photolysis (due to ultraviolet radiations) is surely the predominant mechanism because in the rainy season the vegetated wetland was more efficient in the removal of bacteria than the non vegetated control. the second year presented a similar variability of bacteria concentrations as in the first year. although no significant differences existed between the two years, the first year appeared to be more efficient in faecal bacteria removal than the second. this can be attributed to the high plant density observed in the vegetated wetland in the second year, which may block the u.v radiations from having effect on the bacteria. this observation is contrary to the observations found in literature where the age of the wetlands is suppose to have greater efficiency in the second year as the plants are well established in their roots network with a stable symbiotic relationship with the substrate microorganisms, thus promoting the different removal mechanisms in the wetlands (tchobanoglous, 1987; lee et al., 2009). other mechanisms involved include filtration, sedimentation, adsorption, oxidation, antibiosis, predation and die-off from exposure to toxins of plants and other bacteria (green et al., 1997; kaseva, 2004). the differences between the non vegetated control and the vegetated wetlands may be attributed to the influence of plants. the multiplication of substrate microorganisms and their coordination in the removal processes in the second year is not to be also neglected. the better performances of the vegetated wetland could also be attributed to tropical climate conditions that are 8 known to be suitable all year-round for rapid biological growth, which influence the treatment processes (kaseva, 2004). the wetland vegetated with e. pyramidalis had more effect on the removal of faecal coliforms and was least efficient on faecal streptococci removal. this is thought that, the bactericidal substances which may be produced by this species roots, mixed with the toxic effects of substrate microorganisms have less effect on faecal streptococci, but more on faecal and total coliforms. the passage of wastewater through the non vegetated control wetland resulted in the reduction of several contaminants to considerable levels in different seasons; however, the presence of vegetation further improved the treatment efficiencies except in few cases. the significant removal of most physicochemical parameters was regardless of the presence of vegetation in the treatment wetland as earlier observed by hench et al. (2003). this may be attributed to the shallow depth of the treatment wetlands which may have minimal effect on the treatment processes (coleman et al., 2001). the reduction of bod5, cod and po4 -3 was regardless of the presence of vegetation; however there were significant differences (p˂0.05) between their removals in the vegetated wetland and the control in the second year and not in the first. their concentrations in both the vegetated and the non vegetated control were significantly different from the inflow in both years. the efficiencies of the wetlands in the removal of physicochemical parameters compared to the microbial parameters were higher in the second year than those of the first year. it can be understood that the removal mechanisms for bacteria and those of physicochemical parameters are not the same. in the second year, the massive treatment is richer in substrate bacteria for biodegradation and the root network of the macrophyte is well established in the wetland. secondly, since in the first year, plant roots had not yet reached maximum depth, the treatment processes will likely become higher during the second year of study as the roots would have reached sufficient depth (kern and idler, 1999). in all, the vegetated wetland was generally more efficient in the reduction of parameters. this, in addition to uptake, may also be thanks to their additional aeration at the root zone to facilitate the processes of degradation and detoxification by aerobic microorganisms (lin et al., 2002). in this study the macrophyte bed repeatedly reduced nitrates more than the non vegetated control. this may be due to the functions of plants in constructed wetlands which include uptake of nitrates, supplying organic carbon for denitrification and providing attachment sites for denitrifying bacteria (kadlec and knight, 1995; lin et al., 2002; thullen et al., 2002; lee et al., 2009). cod reductions that were consistently higher in the vegetated wetland could be attributed to the fact that macrophytes and microorganisms depend on nutrients in wastewater for survival. in contrast, their metabolites provide important n and p sources for micro-organisms which are very important mechanisms (ji et al., 2002). conclusion the constructed wetland vegetated with e. pyramidalis in a horizontal surface flow configuration (hsf) was continuously efficient in the removal of faecal indicator bacteria from domestic wastewater for the two years, with no significant differences existing between the seasons of the year and between the years. the age of the wetland generally had a negative influence in the removal of faecal indictors; but this difference was not significant. the constructed wetland vegetated with e. pyramidalis was most efficient in the removal of faecal coliforms followed by total coliforms, but was least efficient in the removal of faecal streptococci as compared to the non vegetated control. the contribution of e. pyramidalis in the removal of 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water sci. technol. 32(3):49-58. in ternationa l scholars journa ls african journal of environmental economics and management issn 2375-0707 vol. 7 (5), pp. 001-005, may, 2019. available online at www.internationalscholarsjournals.org © international scholars journals author(s) retain the copyright of this article. full length research paper ecotourism and its effects on wildlife of pachmarhi biosphere reserve balendra pratap singh* and ravi upadhyay government narmada p.g. college, hoshangabad, india. accepted 15 november, 2018 the present paper focused on ecotourism and its effects on wildlife. in the present scenario the ecotourism is a grooming sector in developing nations. however, its impact on wildlife and indigenous people has become a controversial issue. pachmarhi biosphere reserve site explores the multitude of interactions that exist among the welfare of wildlife, conservation biology and socio-economy of the local people. key words: environmental impact, ecotourism, biodiversity, flora, fauna, landscape ecology, protected area. introduction tourism, especially international tourism, is one of the world’s fastest growing industries. the world has seen an “increase in international tourist arrivals from 25 million in 1950 to 664 million in 1999” (griffin, 2002). people have always had a great desire to travel the world, to experience other environments, and to simulate foreign ways of life. in its most basic sense, tourism can be defined as “travel outside one’s normal home…, the activities undertaken during the stay, and the facilities created to cater for tourist needs” (dowling and david, 2003). however, this description is not as basic as one might think; rarely are the facilities created to cater for tourist needs discussed in tourism. nature tourism is the organized viewing of wildlife. nature tourists pay a considerable amount of money to participate in viewing wildlife in their native countries and in foreign countries that promote nature viewing to attract the revenue of tourists (moreno, 2005). the example of a sustainable use of wildlife in the manu biosphere reserve and puero maldonado national parks of peru in (groom et al., 2000), recognizes the benefits of ecotourism as it helps to educate people on the importance of conserving wildlife. the monetary gain from this industry serves to benefit the conservation efforts to manage wild habitats and provides an income for local people. the main goal of this study is to find key *corresponding author. e-mail: cool_balendrasingh@yahoo.com. indicators and evaluate of ecotourism impact on wildlife of pachmarhi biosphere reserve. study area the total area of pachmarhi biosphere reserve is 4981.72 km 2 . it is located at longitude 22° 11’ to 22° 50’n and latitude 77° 47’ to 78° 52’e. it covers parts of three civil districts, viz., hoshangabad (59.55%), chhindwara (29.19%) and betul (11.26%). it includes three wildlife conservation units viz., bori sanctuary (485.72 km 2 ), satpura national park (524.37 km 2 ) and pachmarhi sanctuary (491.63 km 2 ). these altogether has also been notified as satpura tiger reserve (1501.72 km 2 ) (annonymous, 1996). the places worth being seen at and around pachmarhi area, priyadarshani point, hondi khoh, apsara vihar, rajat prapat, raj giri, lanjee giri, dutches fall, sundar kund, jatashankar, chhota mahadeo, mahadeo, chauragarh, dhupgarh, pandav cave, cave shelters. in bori sanctuary, churna, is a base for tourism. for a truly wilderness experience, the visitor can reach up to neemghan through panarpani gate. the flat land and good visibility along with rich wildlife makes excursions here unforgettable. among them mahadeo, catacomb, jumbudweep, madai, dorothideep, jatashankar , pandav caves, bazar caves, maradeo, kaila khurd, taptka pani, kanjighat, tamia, rajat prapat, kharilanes are important from archaeological point of view. table 1. madai entrance to pachmarhi biosphere reserve. year no. of tourist amount of entry fees allocated indian foreigners 2000-2001 140,493 179 2,158,374 2001-2002 129,023 109 1,943,379 2002-2003 168,915 150 2,653,840 2003-2004 194,608 154 3,115,131 2004-2005 182,714 233 3,621,796 2005-2006 155,091 208 5,050,947 2006-2007 192,044 254 6,062,422 2007-2008 172,832 203 5,123,160 2008-2009 198,336 278 8,287,542 materials and methods the present study is the outcome of exhaustive field and tourist places survey undertaken for the period of one year from december, 2009 to 2010. the survey was conducted in the hotels, guesthouses, rest houses, toll tax booth, bison lodge, beefall, dutchesfall, apsravihar, rajendragiri, bada mahadev, jatashanker, chouragarh, reechhgarh, dhoopgarh, pandav gufa, tawa dam, madai and different villages of pachmarhi biosphere reserve such as panarpani, badkachhar, matkuli, pagara, bariam, amkhedi, neemghan, singanama, tekapar, chaka, pisua, monhgaun, kadari, binoura, kherghat, parraspani, rorighat, kajari, bori, choorna, badianhoni, chhotianhoni, tamia and patalkot in various seasons. key indicators of ecotourism in the process of evaluation of effects of ecotourism on wildlife of pachmarhi biosphere reserve, these indicators have been used: (1) old historic teak forest (2) about 80 km long stretch of tawa reservoir 204 sq man made lake. (3) geological formations (4) ethic geological heritage (5) richness of biodiversity of flora and fauna. (6) pleasant climate (7) beauty of landscape (8) waterfalls (9) sunrise and sunset point (10) many form of god shiva (11) patalkote (12) anhoni (badi and chhoti). results status of biodiversity the study of the floral diversity in the area carried out by state forest research institute, jabalpur in 1993, reported 1381 plant species, which comprise 8 species of algae, 22 of fungi, 83 bryophytes in 34 families, 71 pteridophytes in 16 families, 07 species of gymnosperms and 1190 species of angiosperms. the faunal composition represents the deccan peninsular zone of biogeographic classification of india. most of the pachmarhi biosphere reserve is covered with dense forest vegetation and forms an ideal habitat for wild animals. over 50 species of mammal, 254 species of birds, 30 species of reptiles, 56 species of butterflies and numerous other forms of animals are found in the area. the steep vertical scarps are home to numerous raptors like honey buzzard and black eagle and hawks. these forests have both grey as well as the red jungle fowl, which are usually found separately either in north or south india, respectively. among the other birds represented are malabar pied hornbill, malabar whistling thrush and paradise fly catcher. the presence of numerous streams, dense foliage, wild flowers, woodland edges and damp patches attract numerous colorful butterflies including orange oak leaf, black rajah, great egg fly, blue pansy etc. the structure and dynamics of tourists the main structure and dynamics of tourist in investigated area is presented in the table 1. critics of ecotourism point to the potential harm caused by the intrusion of large numbers of people into wild habitats. the presence of nature tourists is seen to influence behavior or population parameters such as reproductive success and survival of the affected wildlife. these effects can be listed as being direct or indirect. the main animals found are hyena, wild dog, wolf, fox, wild cat, jackal sloth bear, wild boar, gaur, sambhar, cheetah, barking deer, chinkaras, pythons, indian giant squirrel, and flying squirrel. poaching, hunting, illicit and uncontrolled felling and epidemic are the decimating factors for the wildlife management. the quality of richness and size of the territory is proportional to the strength of the male tiger. habitat preference is distinctly shown by herbivorous animals. the indian gaurs, which is a very important animal of this sanctuary, shows a distinct seasonal habitat preference. they resort to local migration within the sanctuary area due to change in food and water availability. bird life is also varied specially in the area adjoining cultivation in the bori region. peafowl, grey jungle fowl, green pigeon, peacock are common in the forests while grey partridges, several kinds of quail and other water birds are seen in the cultivated area along the edge of narmada plains. fish of various kinds and also crabs are found in large numbers in the streams and rivers. in deeper holes even up to a great height crocodiles are reported to be seen in sonbhadra river. in pachmarhi region, green pigeon, blue rock pigeon various doves parakuts, peacocks, racket tailed drongo, golden orioles, the barbets, king fisher, indian roller, night jar, red vented bulbul, red junlge fowl, golden backed wood pecker scarlet minivet crested serpent, eagle and floral diversity tectona grandis, shorea robusta, melastoma malabaricum, murraya paniculata, blumea lanceolaria, isoetes panchanaii, lycopodium cerenum etc are found. direct effects nature tourism can have direct effects on species, communities and populations by influencing their feeding, reproductive and social behaviors medina, 2005. whale watching along the west-coast of north america is based on the migratory route of gray whales. whale-watching allows the visitors to approach whales by boat with disruptive effects on feeding and separation of calves from mothers (hashimoto and david, 2004). it is also likely that the noise made by propellers and boat engines interferes with the sound-communication systems of whales (edington and edington, 1986) observed the effects of nature tourism on american flamingos in yucatan, mexico. the operation of motorized tour boats was seen to result in decreased feeding time and increased alert behavior in response to the tour boats (galicia et al., 1997). ecotourism activities affect populations of megallanic penguin populations. human visitation to nesting sites of megallanic penguins caused changes in behavior in both adults and chicks, such as higher predation of nests, lower hatching rates of eggs, increased abandonment of nests, retarded chick growth and higher mortality rates (fowler, 1999). klein (1995) observed effects on water bird communities in the ding darling national park. there was a marked difference between the behavior of water birds that used the reserve as a feeding and breeding ground to those species that used it as an over-wintering site. the migratory birds were clearly unaccustomed to the humans and fled at the mere site of humans and cars. indirect effects indirect effects of ecotourism are: loss of vegetation, pollution of air, streams and terrain caused by tourist support facilities, loss of camouflage, increase in predation, intra/inter-specific competition and introduction of pests (cole and landres, 1995). the indirect effects are not as conceivable as the direct effects and can cause long-term damage to wildlife habitat which can directly affect the survival of wildlife. indirect effects are a result of poor management and regulation of ecotourism coupled with socio-economic factors. in nepal, yonzon and hunter (1991) and haysmith and hunt (1995) reported a chain reaction effect on red pandas by a tourism-driven market for local cheese. in an effort to meet the demand for cheese production, local cattle overgrazed large areas causing habitat destruction for the red panda population. these effects are largely due to economics of the industry that is governed by the consumptive behavior of the tourists (haysmith and hunt, 1995). current problems authors would like to look at the effects of ecotourism in developing countries. most of the world's natural rain forests that are found in tropical ecosystems are home to a large proportion of endemic flora and fauna species. most tropical countries are found in south america, africa, south and south-east asia. natural forests are being encroached by an expanding population and by the use of biological resources for economic development (timber, poaching etc.). the development of ecotourism can help save forest lands by encouraging a nonconsumptive use of wildlife while generating valuable foreign income. however, the development of ecotourism can create an unequal distribution of income contributing to socio-economic problems, affect wildlife and indigenous people and conflict with conservation efforts. the stake-holders of the tourism industry are a few leading tour companies that collaborate with lodges and tour groups. therefore, the local communities do not benefit from the revenue. local people may create a market for poaching and other forest products to sell to tourists and contend with the tourism industry (benson and clifton, 2004). a tourism industry needs to be supported by building suitable infrastructure. the construction of roads, buildings and introduction of electricity can result in fragmentation of wildlife and habitat destruction. the use of vehicles for transportation can disturb wildlife directly through noise and overuse of critical areas such as nesting areas, feeding grounds and water holes. indirect effects can result in habitat degradation through pollution and alteration through trail cutting (groom et al., 2000). conservation efforts to protect valuable wildlife and their forest habitats may conflict with the interests of local communities. therefore, intentions of conservation can be misunderstood by the local communities (crouch and scott, 2003). such conflicts can result in a lack of trust and cooperation between local communities and conservationists. why is it a problem? madhya pradesh governments lack guidelines and regulations that protect natural resources from negative effects of ecotourism. the inability to enforce the law on the consumptive use of forests can result in an unchecked depletion of natural resources the country depends on. regulations regulations need to reflect the value of forests and wildlife while also considering the need to sustain lives of indigenous people. the regulations should also try to minimize the impact of ecotourism on the welfare of wildlife and native communities. most developing nations are facing economic problems and civil and political strife. the fickle nature of politics in most developing nations (zaire, peru, sri lanka, india etc) together with a multitude of other problems makes forest and wildlife protection seem like a needless endeavour. presently, conservation groups such as ngo's, unesco, world wildlife fund (wwf) and sierra club are trying to implement the conservation of priority species and ecosystems (johnson, 1995). the scientific knowledge in wildlife welfare and ecosystems are concentrated in educational institutions. local governments have some regulations on protecting forests; however, most regulations are not implemented. therefore, conservationists need to contend with the priorities of different groups together with funding problems when setting priorities to protect wildlife and their habitats. discussion in 1971 the annual tourist inflow to pachmarhi was about 4,500. this has increased to about 66,000 in 1992. presently the inflow of tourist is around 75,000 to 80,000. domestic tourists mostly visit pachmarhi. maximum number of tourists visits in the month of may. however, april, may and june prior to on-set of monsoon and october to december after rainy season are the main tourist inflow months. mostly people from maharashtra, gujrat and west bengal visit the area. the people visiting the area can be grouped in two categories, viz. students, and general tourists. in addition, annually around 3-4 lakhs of piligrims flock the shrines of mahadeo and nagdwari during shivratri and nag panchami festivals. during these festivals, people travel along the roads enmasse, camp over night, cook their food and defecate as per their convenience, creating a lot of environmental problems. therefore it is necessary to regulate the activities of the piligrims. being the only hill resort in the state, the number of tourist arrivals has increased considerably during the last decade. the growth of tourism has resulted in negative impacts like pollution of water at tourist's spots, vandalism littering and problems of garbage disposal. the increase in tourist arrivals has also resulted in the increase in the number of hotels and tourist lodges. this has led to migration of labour from neighbouring villages and the mushrooming of shanty towns. there has been a substantial increase in vehicular traffic on pachmarhi leading to air emissions and noise pollution. if ecotourism is to benefit wildlife and the tourism industry, measures need to be taken to study the long-term effects of nature viewing on wildlife ecosystems, dynamics of the wild species and their environment, and a thorough knowledge of the wild species and their behavior. further, there should be a strict regulation of ecotourism activities with the understanding of the participants and their willingness to cooperate to ensure the preservation of wildlife and their habitat. in developing countries, ecotourism should encourage the involvement of local communities in the industry to practice stewardship of their natural resources. raising children with the knowledge about the costs and benefits of ecotourism puts them at a great advantage for generations to come, making continuing a sustainable tourism practice much more likely (wearing, 2001; weaver 2002). a universal program would be able to set rules and monitor the progress of ecotourism around the world. monitoring would not have to be an elaborate process, however; monitoring “can occur through a range of formal and informal means, including informal conversations, group discussions, and questionnaires” (wearing, 2001). steps to success (1) set biodiversity priorities that link with conservation goals. (2) clarify local, national and global bio-diversity conservation priorities. (3) involve those responsible for implementing conservation actions: government agencies, ngos, local universities and local communities. (4) give local people economic incentives to protect wildlife ecosystems. (5) involve government policy makers in conservation efforts to declare protected areas and enforce regulations. references annonymous (1996). pachmarhi biosphere reserve, project document (environmental planning and coordination organizationepco), bhopal. benson a, clifton j (2004). assessing tourism’s impact using local communities’ attitudes toward the environment. in sustainable tourism, eds. f.d. pinela and c.a. brebbia. wit press, pp. 3-12. crouch d, scott m (2003). culture, consumption, and ecotourism policies. in ecotourism policy and planning, eds. ross dowling and david fennell. cabi publishing, pp. 77-98. diamantis d (2004). ecotourism management: an overview. in ecotourism, ed. dimitrios diamantis. thomas, pp. 3-26. dowling r, david f (2003). the context of ecotourism policy and planning. in ecotourism policy and planning, eds. ross dowling and david fennell. cabi publishing, pp. 1-20. griffin t (2002). an optimistic perspective on tourism’s sustainability. in sustainable tourism: a global perspective, ed. rob harris, tony griffin, and peter williams. butterworth heinemann, pp. 24-32. hashimoto a, david t (2004). canadian aboriginal ecotourism in the north.” in ecotourism, ed. dimitrios diamantis. thomas, pp. 204-225. medina lk (2005). ecotourism and certification: confronting the principles and pragmatics of socially responsible tourism. j. sustain. tourism, pp. 281-296. moreno p (2005). “ecotourism along the meso-american caribbean reef: the impacts of foreign investment.” hum. ecol., 33(2): 217244. wearing s (2001). exploring socio-cultural impacts on local communities. in the encyclopedia of ecotourism, ed. david weaver. cabi publishing, pp. 395-410. weaver d (2002). perspectives on sustainable tourism in the south pacific. in sustainable tourism: a global perspective, ed. rob harris, tony griffin, and peter williams. butterworth heinemann, pp. 121-139. in ternationa l scholars journa ls african journal of environmental economics and management issn 2375-0707 vol. 5 (2), pp. 286-289, february, 2017. available online at www.internationalscholarsjournals.org © international scholars journals author(s) retain the copyright of this article. full length research paper challenges of open dumping of animal wastes on the environment: a case study of s and d farms, odeda, nigeria james akintola, balogun lateef and jude abiola department of environmental science, citygate university, ibadan, oyo state, nigeria. accepted 03 january, 2017 the study investigated the effect of open dumping of animal wastes on the farm workers’ health and the environment. the study employed chi-square’s test of result reliability revealed on hypothesis tests. the χ 2 calculated value 0.013 for hypothesis i which is less than χ 2 tabulated value of 3.84 at level of significance 0.05, indicates that the open dumping of animal wastes as a method of disposal has significant effect on health of the workers and the environment. similarly for hypothesis ii; χ 2 calculated value of 0.06 is far less than the χ 2 tabulated value of 3.84 at level of significance 0.05. this implies that level of waste disposal education of the workers significantly affects the method of disposal being employed on the farm. for the hypothesis iii; χ 2 calculated value of 0.05 is also less than the χ 2 tabulated value of 3.84 at level of significance 0.05, implying that the industrial training being given to the workers on waste disposal methods is not adequate. keywords: animal waste, open dumping, waste disposal, waste management. introduction animal wastes include livestock and poultry manure, bedding and litter, waste water, feedlot runoff and even wasted feed (ajayi, 2008). animal wastes abound when too much waste is produced by farm animals in a particular environment with no safe or cost-effective means to either use the wastes productively or dispose off overtime (david, 1993). these wastes can affect the air or water quality if proper practices are not followed. waste from animal concentrations which are not protected can wash into nearby streams. such diffused flow of animal waste is referred to as non-point source (nps) pollution (downing and gibson, 1984 and oreyemi, 1988). non-point source pollution is the largest remaining water quality problem in united states (john and steven, 1999). in nigeria, approximately one third of the agricultural nps pollution is caused by animal waste run-off from feedlots, holding areas and pastures (john and steven, 1999). such waste in surface waters reduces dissolved oxygen (do) and endangers aquatic life. the added nutrient produces excessive algae growth therefore causing eutrophication, unpleasant taste and odours. drinking of water with nitrate concentration above 10ppm can cause development deficiencies in infants and death in severe cases due to oxygen deprivation (akinsanmi, 2000). high nitrate concentration is also believed to have caused spontaneous abortion and possibly cancer in farm animals (rached et al., 2001). animal waste should therefore be disposed off properly and regularly to avoid wastes emitting pungent obnoxious odour and also prevent favourable breeding place for microbes, which could aid the spread of diseases (barth, 1995). a waste management system should be a part of the total soil and water conservation plan for farms producing livestock and poultry. therefore, it is important to examine and evaluate vividly the nature of waste generated, as well as disposal methods employed by the farm to determine whether it is adequate or not. materials and methods study area serah and deborah (s and d) farms is situated along abeokuta-ibadan road in odeda local government area of ogun state, southwestern nigeria. corresponding author. e-mail:james_akintola@gmail.com akintola et al. 287 table 1. effect of open dumping on workers and environment variables agreed not agreed total ha 25 32 57 ho 27 36 63 total 52 68 120 the farm covers 0.5km 2 expanse of land with staff strength of 250. the farm consists of livestock, fishery and poultry sections which are well equipped for mass production of meat, fish and poultry products. research methodology 120 copies of questionnaire were randomly distributed among the staff of the component units of the farm. they were later retrieved and processed. observation of the work process and environment was also carried out vis-àvis the waste disposal method adopted by the farm. hypotheses three hypotheses were tested and are listed below:  hypothesis i  ha: open dumping disposal of waste tends to have negative effect on the workers and the  environment  ho: open dumping disposal of waste does not tend to have negative effect on the workers and the environment.   hypothesis ii  ha: level of waste disposal education of the  workers affects the method being used.  ho: level of waste disposal education of the workers does not affect the method being used.   hypothesis iii  ha: industrial training on waste disposal  methods in the farm is inadequate  ho: industrial training on waste disposal methods in the farm is adequate  chi-square test in order to validate the hypothesis, chi-square or goodness of fit test was used to test data collected quantitatively. χ2 = σ (___ ) _ _ where: χ 2 = test statistics σ = summation o =observed frequency e = expected frequency (r) = no. of rows (c) = no. of columns df = degree of freedom df = (r – 1) (c – 1) = (2 – 1) (2 – 1) = (1) (1) = 1 results the response to the effect of open dumping of animal wastes, as a method of disposal, on workers and the environment is presented in table 1. 25 out of 57 respondents agreed with ha while 32 out of 57 did not, 27 out 63 respondents agreed with ho while 36 out of 63 did not. hypothesis i ha: open dumping disposal of waste tends to have negative effect on the workers and the environment ho: open dumping disposal of waste does not tend to have negative effect on the workers and the environment level of significance at 0.05 let test statistics be χ2 = σ (___ ) _ _ df = (r – 1) (c – 1 = (r – 1) (c – 1) = (2 – 1) (2 – 1) = (1) (1) = 1 decision rule: reject ho if χ 2 calculated is greater than χ 2 tabulated. compute test statistics e1 = _ __ = 24.7 __ e2 = _ __ = 32.3 __ e3 = __ __ = 27.3 __ e4 = __ __ = 35.7 __ oe o – e(o – e) 2 (_ − _ ) _ _ 25 24.7 0.3 0.09 0.004 32 32.3 -0.3 0.09 0.003 27 27.3 -0.3 0.09 0.003 36 35.7 0.3 0.09 0.003 0.013 χ 2 calculated = 0.013 χ 2 tabulated (0.05) = 3.84 288 afr. j. environ. econ. manage. table iii. level of industrial training of the workers on table 2. effect of waste disposal education on method waste disposal methods adopted variables agreed not total variables agreed not agreed total agreed ha 26 32 58 ho 29 33 62 total 55 65 120 yes 25 32 57 no 29 34 63 total 54 66 120 since χ 2 calculated is less than χ 2 tabulated (i.e. 0.013 < 3.84 respectively) we reject the ho and conclude that open dumping method of waste disposal tends to have negative effect on the workers and the environment. hypothesis ii ha: level of waste disposal education of the workers affects the method being used. ho: level of waste disposal education of the workers does not affect the method being used. the effect of waste disposal education given to the workers on method adopted by the respondents is shown on table 2. 32 out of 58 respondents did not agree with ha while 29 out of 62 agreed with ho; this invariably implies that 61/120 x 100 (i.e. level of significance = 0.05 let test statistics be χ2 = σ (___ ) _ _ df = (r – 1) (c – 1) decision rule: reject ho if χ 2 calculated is greater than χ 2 tabulated compute test statistics e1 = __ __ = 26.9 __ e2 = __ __ = 31.4 __ e3 = __ __ = 28.4 __ e4 = __ __ = 33.6 __ o e o – e (o – e) 2 (_ − _ ) _ _ 26 26.9 -0.9 0.81 0.03 32 31.4 0.6 0.36 0.01 29 28.4 0.6 0.36 0.01 33 33.6 -0.6 0.36 0.01 0.06 χ 2 calculated = 0.06 χ 2 tabulated = 3.84 since χ 2 calculated is less than χ 2 tabulated (i.e. 0.06 < 3.84) we reject the null hypothesis and conclude that the level of waste disposal education of the workers significantly affects the method of the disposal being employed. hypothesis iii ha: industrial training on waste disposal methods in the farm is inadequate ho: industrial training on waste disposal methods in the farm is adequate (see table 3) level of significance at 0.05 let test statistics be χ2 = σ (___ ) _ _ df = (r – 1) (c – 1) = (2 – 1) (2 – 1) = (1) (1) = 1 decision rule: reject ho if χ 2 calculated is greater than χ 2 tabulated compute test statistics e1 = _ __ = 25.7 __ e2 = _ __ = 31.4 __ e3 = __ __ = 28.4 __ e4 = __ __ = 34.7 __ o e o – e (o – e) 2 (_ − _ ) _ _ 25 25.7 -0.7 0.49 0.02 32 31.4 0.6 0.36 0.01 29 28.4 0.6 0.36 0.01 34 34.7 -0.7 0.49 0.01 0.05 χ 2 calculated = 0.05 χ 2 tabulated = 3.84 since χ 2 calculated is less than χ 2 tabulated (i.e. 0.05 < 3.84) we reject the null hypothesis and conclude that industrial training on waste disposal methods in the farm is significantly inadequate. discussion the open dumping method of waste disposal adopted in the farm has significant effect on the workers and the akintola et al. 289 environment. this is evident from the result of hypothesis i. the dumping site creates growth conditions for disease vectors, insect pests also lay their eggs on the rotten wastes. this later hatch and invade the farm animals (olusi, 1998) and workers inclusive. result of hypothesis ii shows that the workers adopted the open dumping method because they had little knowledge about any other safer and more hygienic methods of waste disposal. the farm has been using this method year-in year-out since its inception; they possibly consider open dumping method as the cheapest. moreover, the wastes generated while the farm was still small, at the inception, were considerably low to what is being generated now when the farm is big. hence, the farm needs to review and change the open dumping method being used year long (ajayi, 2008). hypothesis iii shows that the workers were not adequately informed on various safer and more hygienic waste management methods. hence they are limited to open dumping, thereby recording low waste management and poor prevention of air-pollution and air-borne diseases. the whole heap of the dump site creates obnoxious odour and encourage the growth of pathogens and insect pests lay their eggs on the heap (madukwe et al., 1996). recommendation agricultural wastes can be used as a form of resource recovery; the waste can be reused in the term of waste recycling. waste management in form of organic manure can improve overall farming operations as well as improving the environment while reducing fertilizer costs. frequent and up-to-date waste disposal review is also very important so as to check the impact of a waste disposal method being used. s and d farms should therefore embark on waste management plan, which allows the farmers to fully utilize the plant and animal waste to reduce cost. the management should also organize seminars on regular basis to keep their workers abreast of safe and hygienic methods of waste disposal. references ajayi ff (2008). solid waste management problem and its implication on health, environmental management in nigeria, vol.11, pp. 34 – 38. akinsanmi, o. (2000): pollution control for animal production, journal of agricultural management, vol. 6. pp. 112 – 115. barth cl (1995). livestock waste characteristics; a new approach, agricultural waste utilization and management. 5 th international symposium on agricultural wastes. pp 286 – 294. david d (1993). waste disposal methods in agricultural industries. 3 rd ed. academic press inc. florida pp. 17 – 21. downing, gibson (1984). how do chemical substances affect the environment? archives of environmental contamination and toxicology, vol. 15: pp. 427 – 434. john bn, steven w (1999). farm waste management. granid publishing ltd. 2 nd ed. great britain. pp. 291 – 299. madukwe mc, okoli ec, eze so (1996). analysis and comparison of the agricultural technology transfer system in nigeria. african journal of agricultural research. vol 26 pp.111 – 115. olusi jo (1998). agricultural technology adoption on small-holding farmers; policy options for nigeria. journal of food science. vol. 7 pp. 617 – 624 oreyemi mk (1998). ecological sanitation of water and environmental conservation technology options: the case study of slums in oyo state, nigeria. j. african environmental issues, vol. 3. pp 12 – 16. rached e, rathgeber, brooks db (2001). water management in africa and the middle east – challenges and opportunities, international development research council (idrc). canada. in ternationa l scholars journa ls african journal of environmental economics and management issn 2375-0707 vol. 8 (3), pp. 001-012, march, 2020. available online at www.internationalscholarsjournals.org © international scholars journals author(s) retain the copyright of this article. full length research paper evaluation of three classifiers in mapping forest stand types using medium resolution imagery: a case study in the offinso forest district, ghana baatuuwie, n. b and ir. louise van leeuwen* 1 faculty of renewable natural resources, university for development studies, p. o. box tl 1882, tamale, ghana. 2 international institute for geo-information science and earth observation, enschede, the netherlands. accepted 12 december, 2019 loss of ghana’s natural forests has been counteracted by plantation establishment and development. as at 2003, ghana had a plantation area of about 97,000 hectares comprising different tree species. with the rapid expansion of plantations in the country, it is anticipated that major managerial challenges will arise due to insignificant technical personnel for monitoring and management. the application of gis and remote sensing will be a powerful intervention and tool for monitoring and managing these forest resources in the area. the aim of this study was to determine a suitable method of mapping the different forest stand types using medium resolution images in the study area. three classifiers were examined for their suitability in mapping the different forest stand types in the area (maximum likelihood, spectral angle mapper and decision tree). the results showed that using maximum likelihood classifier and aster imagery, different forest stand types can be accurately mapped with an overall accuracy of 88.50%. key words: geo-referenced, classification, algorithm, spectral, mapper. introduction ghana’s total land area of 238,500 km 2 is made up of savanna (56%); closed forest (35%) and the remaining represents other land cover. all the vegetation types in ghana, except for those comprising the savanna, are considered tropical forests and located in the southern belt of the country (blay et al., 2007). these forests play very vital roles in supporting the livelihood of the inhabitants of ghana in various ways. trading in non-timber forest products (ntfps: chewing sticks, pestles, canes, nuts, fruits, bush meat, fodder, artifacts and medicine extracted from the forest) are economically important within all areas of the high forest zone (blay, 2004) . the forest also serves as haven for numerous species of flora and fauna, and generally helps maintain the biological diversity of the area (abeney and owusu, 1999). it also contains many genetic materials of known and yet to be discovered species of importance (blay, 2004). *corresponding author. e-mail: taawiebernard@yahoo.com. regardless of the substantial contribution of the forest resources to the economy, degradation of ghana’s forest resources is assuming an alarming proportion. it is estimated that about 60% of the reserved forests are degraded (ted, 1997; fao, 2000). it was reported that 26% of the forest cover was lost between 1990 and 2005 (mongabay.com, 2006). like many other tropical countries, the loss of ghana’s natural forests has been counteracted by comprehensive reform programmes in the forestry sector (mlf, 2004). key among the reforms was the government’s initiative in establishing plantation in the country. plantation forestry can be used as a tool not only to halt forest degradation but also to catalyze important native forest flora restoration after long period of anthropogenic and non-anthropogenic disturbances (lemenih and teketay, 2004). ghana by 2003 had a plantation area of about 97,000 ha (mlf, 2004). with the rapid expansion of plantations in ghana, it is anticipated that major managerial challenges will arise due to insignificant technical personnel for monitoring and management. the application of geographic information system (gis) and remote sensing will be a powerful intervention and tool for monitoring and managing these forest resources in the area. gis and remote sensing have been utilized in many regions over the past few decades for both mapping and monitoring forest resources. maintenance of ecosystem integrity and protection of forest diversity are essential processes to achieve sustainable forest management (jensen and everett, 1994). to achieve these multiple objectives, remote sensing techniques have the capability of providing multi-scale, spectral, spatial, and temporal information in a consistent format to help forest managers meet their management objectives (huggins, 2006). it was acknowledged at the environmental conferences in rio de janeiro and kyoto that satellite imagery will offer the most promising and is most likely the only feasible way for a detailed mapping and monitoring of forests resources over large geographical areas per unit time (de carvalho et al., 2004). remote sensing data and other supplementary data that is being produced on regular basis allow researchers to study natural forest processes, such as forest succession, encroachment and regeneration, which were previously limited to small geographical areas and often times impracticable (huggins, 2006). thus remote sensing may be considered the only viable option for monitoring forest succession in a timely and cost effective manner (song and woodcock, 2002). extracting this information from the data is however accomplished by image classification (lillesand and kiefer, 2000). there are several techniques and variations exist between these techniques for extracting thematic information from an image (huggins, 2006). each technique is superior over the other depending on how accurately it identifies and maps the resource/feature, its cost and time effectiveness (franklin, 2001). mapping accuracy will depend on the spectral characteristics of the resource/feature to be mapped. in this study, the different forest cover types in the study area are mapped. the forest stand types in the study area differ from the standpoint of tree species composition. however there are no definite and explicit boundaries between these forests stand types and other vegetation types in the area. in a nutshell, these vegetation types are seen as the same forest cover type on the satellite data due to their similar species composition. there is need to identify an effective classification/mapping procedure that will discriminate between these forest cover types with least cost and human intervention (franklin, 2001), if reliable estimates of forest cover are to be made frequently over large geographical areas over time for strategic forestry planning and decision making (dees et al., 2003). this study was therefore conducted to determine a suitable method for mapping forest stand types in the study area using medium resolution images. three image classification algorithms were then considered and used for this research: maximum likelihood classifier, spectral angle mapper and decision tree classifier. materials and methods description of the study area the study was conducted in the afram headwaters forest reserve (figure 1) located in the offinso district of ashanti region of ghana. the reserve lies between longitude 1º 32’w and 1º 48w and 6º 45’n and 7º 25’n. it covers 20,100 hectares, comprising both natural and plantation forests. the reserve is fringed by eight villages, with their inhabitants depending heavily on the reserve for sustenance. each of the communities has a population size of not less than 600 people (ghana statistical service, 2000). due to heavy dependency of this populace around the reserve, it has consequently subjected the forest reserve to various forms of human activities leading to its fragmentation and degradation. consequently, there are ongoing restoration programmes in the reserve through plantation establishment by the government and private developers. plantation establishment methods employed are mainly monoculture of exotic tree species such as cedrela odorata (cedrela) and tectona grandis (teak) and mixed stands of local tree species. land covers data collection an ipaq (handheld computers) equipped with an internal global positioning system receiver was used to capture coordinates of pre-determined land cover samples which were used as training set for image classification and testing data for the accuracy assessment of the classification. it is recommended that 50 points be collected per land cover for image classification and accuracy assessment (curran, 1985). however due to time constrain, 219 points were collected for all land cover types. image processing and classification a geo-referenced and atmospherically corrected aster february 24, 2008 image was obtained from itc geo-database. the image was re-projected from geographic coordinate system (wgs84) to the ghana local coordinate system in erdas image processing software. the aster image was classified using the three classifiers: maximum likelihood, spectral angle mapper and decision tree. the main aim was to assess the performance of the three classification algorithms using medium resolution data acquired from the aster sensor in the study area. their performance was based on the ability to identify different forest stand types accurately based on ground truth data (mohd, 2007) with minimum time and cost (franklin, 2001) . overall classification accuracies as well as the kappa statistics were calculated for each of the classifiers used and their results compared. the maximum likelihood classifiers supervised classification using maximum likelihood algorithm was figure 1. study area showing afram headwaters forest reserve on aster image. applied for classification of the image. supervised classification technique using maximum likelihood algorithm is the most commonly and widely used method for land cover classification (jia and richards, 2006). in australia, the maximum likelihood classifier was effectively used to map different forest stand types with high precision (chia et al., 2005). stated below are steps involved in the procedure for achieving image classification using the maximum likelihood classifier: training sample selection for classification: training samples were collected on the aster image to train the classifier. one hundred and six (106) training sets were used for the classification. during analysis, five land use/cover classes were considered: buildup/bare (15 training sets), teak plantation forest (15 training sets), new plantations (24 training sets), natural forest (26 training sets) and mixed/degraded forest (26 training sets). the quality of a classification output is dependent on how training samples were collected (franklin, 2001). to ensure high accuracy, the selection of the training samples was aided by feature space in bands 2 and 3 which gives an idea of the homogeneity and spectral separability between the forest classes. assessing the normality of the training sample: normal distribution of the training samples is the basic requirement of the maximum likelihood classification. therefore, training samples were subjected to normality test using the histogram plot control curve. for a normal distribution, the histogram shows bell shaped curve. outliers are often located in the tail ends of the curve. the histograms of the training samples of the various classes in bands 1, 2 and 3 are shown in figures 2 to 6. means of the classes differ from band to band. nevertheless the data distribution shows the same trend in the different bands; thus, majority of the training pixels have values close to the mean and only a few are outliers. this form of distribution makes it suitable for the maximum likelihood classification. the spectral angle mapper (sam) as with all supervised classifications, sam requires that the user teak teak teak band number 1 band number 2 band number 3 histogram histogram histogram figure 2. histogram of class teak plantation. figure 3. histogram of class build-up/bare. band number 1 band number 2 band number 3 histogram histogram histogram figure 4. histogram of class mixed/degraded forest. figure 5. histogram of class natural forest. figure 6. histogram of class new plantations. defines the training classes and training spectra for the classification. the mean measurement vector for a training class is the vector representation of its mean spectrum. the creation of training classes can be accomplished in one of several ways in envi. one way is to define a set of regions/area of interest (rois) for pixels in the image for which you have ground truths. the mean measurement vector for a given roi training class is simply the mean measurement vector for all the pixels in that class. a second way of defining training classes is to import spectra from spectral libraries. for this study, the former method was used to create the class training set. rois here designate the spectral signatures of the five classes (bare, mixed/degraded forest, teak forest, natural forest and new plantations). in all, 77 rois were used to train the classifier for the classification. decision tree the decision tree is made up of a series of binary decisions that are used to categorized pixels into classes. the decisions can be based on any characteristic of the dataset that is available. for current research, image dn values were extracted and used to create the decision tree. based on the ground truth, regions of interest of the various land use/cover were obtained and the spectral values extracted for inputs in the decision tree. with the exception of the build-up/bare, maximum and minimum dn values of bands 2 and 3 of the image were used to develop the expressions for the forest stand types (table 1). band one was used to develop an expression for the build-up/bare. even though the decision tree classifier is not commonly employed within table 1. input expressions for the decision tree. classes expression border (b1 eq 0) and (b2 eq 0) and (b3 eq 0) build-up/bare (b1 ge 165) and (b1le 169) teak forest (b2 ge 104) and (b2 le 118) and (b3 ge 77) and (b3 le 92) new plantation (b2 ge 104) and (b2 le 110) and (b3 ge 93) and (b3 le 95) degraded forest (b2 ge 98) and (b2 le 105) and (b3 ge 96) and (b3 le 101) mixed forest (b2 ge 99) and (b2 le 106) and (b3 ge 96) and (b3 le 102) natural forest (b2 ge 94) and (b2 le 112) and (b3 ge 84) and (b3 le 99) b= band, ge= greater than, eq= equal to, le= less than. figure 7. decision tree scheme. classical remote sensing, it has been shown to produce a higher level of classification accuracy in mapping features than that of the traditional method of maximum likelihood supervised classification (pal and mather, 2003). figure 7 shows the decision tree scheme that was developed for the image classification. each decision node is named for the class it is intended to classify and if a pixel meets the criteria at that node it is assigned to that class. if it does not meet up the criteria, then it moves down the tree to the next decision node. within the classification image, the colour represented within the “yes” result of a decision node is the actual colour that the class will be represented (huggins, 2006). accuracy assessment of classification to evaluate the performance of a classifier by the use of the methods mentioned in the preceding chapter, it requires that a randomly selected set of test samples (pixels) for each land cover class is used for computing the classification accuracy (richards, 1993). in this study, accuracy assessment was performed with 113 test samples. the test samples were carefully chosen in such a way that they were equally distributed geographically with the training data set. the classified images were then crossed with the test data to generate error matrices for the calculation of the various accuracies (producer’s, user’s accuracy, class mapping accuracy for each class and the overall accuracy) as well as the kappa statistics. a significance test of difference between the classification methods was performed between the confusion matrices using the z test with = 0.05. classification outputs were also assessed qualitatively by visual examination of the classified maps in relation to the field knowledge. this is to ascertain whether the classification outputs matches reality. results the maximum likelihood classification output figure 8a shows the classification output of the maximum likelihood classifier. brown locations in the map represent buildup/bare areas. the rest are different forest stand types in the area. by ocular examination, it is quite clear that build-up/bare area covers smaller proportion of the area while teak plantations and natural forest cover equal proportion of the area. by quantitative analysis, the maximum likelihood classification output build-up/bare figure 8a. output of maximum likelihood classification. classification identified 5639.80 hectares of the total area covered by teak plantations which is the highest, while build-up/bare covered the least area of 280.34 hectares (figure 8b). spectral angle mapper (sam) figure 9a shows classification output of the spectral angle mapper (sam). the colour designations match those used for the maximum likelihood classification. unlike the maximum likelihood classifier, sam identified natural forest to cover the largest proportion of 6963.33 hectares whiles mixed/degraded forest was identified to cover the least of 517.16 hectares (figure 9b). thus, the estimated area covered by mixed/degraded forest is three times lower than that estimated by the maximum likelihood classifier. it is also clear from visual examination that the sam also estimated large area covered by build-up/bare than that of the maximum likelihood classifier. decision tree classification output the map displayed in figure 10a is the output of the decision tree classifier. it estimated a large area covered by natural forest. the area covered by this forest stand type is 8269.49 hectares. build-up/bare like that of the maximum likelihood classifier was detected the least covering an area of 1048.46 hectares (figure 10b). however the area covered by build-up/bare estimated by decision tree is still higher than that estimated by the maximum likelihood classifier. compared with the previous two classifiers (ml and sam), the decision tree classifier estimated the least area covered by teak plantations by 4362.91 hectares. nevertheless, it estimated the largest area covered by natural forest. comparison of classification accuracies of the three methods table 2 shows the summary of the overall accuracy and figure 8b. area representation of the different land use/cover classes. spectral angle mapper classification output buildup/bare figure 9a. classification output of spectral angle mapper. a re a s i n h e c ta re s land use/cover type figure 9b. area representation of the different land use/cover classification. figure 10a. output of decision tree classification. kappa statistics of the three classifiers. the maximum likelihood classifier had the highest classification accuracy of 88.50% while the spectral angle mapper had the lowest of 69.03%. the maximum likelihood classifier again had the highest kappa value of 0.85 and the spectral angle mapper had the lowest value of 0.62. the significance of this difference was tested using the z-test. the z-test showed that the maximum likelihood classifier is significantly higher than the spectral angle mapper (ztest: z= 3.5, p= 0.0004). there is no significant difference between the accuracies of the maximum likelihood and the decision tree classifier (z-test: z= 1.46, p= 0.144). decision tree and spectral angle mapper differ significantly in the accuracies at (z-test: z= 2.10, p= 0.029) apart from the overall accuracy and the kappa figure 10b. area representation of the different land use/cover classes. table 2. summary of accuracy results of the three classifiers. classifier overall accuracy (%) kappa coefficient maximum likelihood 88.50 0.85 decision tree 81.74 0.77 spectral angle mapper 69.03 0.62 table 3. comparison of user’s and producer’s accuracies of the three classifiers. class producer©s accuracy (%) user’s accuracy (%) ml dt sam ml dt sam teak forest 89.66 79.31 86.21 83.87 85.19 83.33 build-up/bare 76.92 84.62 92.31 100 91.67 75 mixed/degraded 100 94.29 37.14 87.5 89.19 100 natural forest 94.12 94.12 94.12 100 72.73 42.11 new plantations 68.42 52.38 63.16 81.25 78.57 75 statistics, producer’s and user’s accuracy were also examined to determine the accuracy of the different classification methods. user’s and producers accuracies are necessary for this study as the main aim is to map the forest categories. the user’s and producer’s accuracies when compared (table 3) revealed that the maximum likelihood has a maximum producer accuracy of 100% for mixed forest with user accuracy of 87.5% , decision tree recorded 94.29% as a maximum producer accuracy for mixed/degraded forest with user’s accuracy of 89.19%. spectral angle mapper recorded its maximum producer accuracy of 94.12% for natural forest with it counterpart user’s accuracy of 42.11%. the least producer’s accuracy of maximum likelihood, decision tree classification and the spectral angle mapper are; 68.42, 52.38 and 37.14% respectively (table 3). the least user’s accuracies for the three classifications methods included: maximum likelihood (81.25), decision tree classification (72.73) and spectral angle mapper (42.11). based on the confusion matrix, it was also clear that some classes were confused with others. this may be due to the spectral heterogeneity of these features in the landscape of the study area and thereby become a hindrance to excellent mapping. in addition, out of the 113 reference pixels, maximum likelihood classifier accurately classified 100 pixels whiles spectral angle mapper and decision tree classifiers accurately classified 75 and 94 pixels respectively. discussion comparison of image classification methods the forest cover mapping using image classification will be incomplete if the classification accuracies are not known. thus accuracy assessment is a fundamental principle in assuring the quality of thematic maps for their intended application (stehman and czaplewski, 1998). this principle determines how useful and applicable a particular classification method is (huggins, 2006; campbell, 2002). it is also the surest way to compare different classification methods. however, costeffectiveness and technical uncomplicatedness are also key factors determining the usability and applicability of the method (franklin, 2001). methods that are less expensive and technically simple will always be opted if the classification accuracies are not significantly different (congalton and green, 1999). all these factors however will depend on the purpose and financial value of the resources (hussin and atmopawiro, 2004). comparison of the accuracies between the three classifiers indicated that the maximum likelihood classifier has the highest classification accuracy of 88.50%, followed by the decision tree with classification accuracy of 81.74%, and the spectral angle mapper recorded the lowest of 69.03%. an overall accuracy of 85% is considered standard for land cover mapping (campbell, 2002). with reference to this overall accuracy, only the maximum likelihood classification has met this standard while the other two classifiers (decision tree and spectral angle mapper) have overall accuracies lower than this standard value recommended by campbell (2002). this means that the maximum likelihood classification technique is a better method in mapping the forest cover types in the study area than both spectral angle mapper and decision tree classifiers when using medium resolution images. further comparison of the mapping accuracies of the three classifiers by their kappa statistics (khat) showed that the maximum likelihood classifier still performed better in mapping the forest cover types in the study area than the two classifiers with a kappa value of 0.85 while the decision tree recorded 0.77 and the spectral angle mapper had the lowest value of 0.62. apart from the overall accuracy and the kappa statistics, class-wise mapping accuracy measurement such as producer’s accuracy and user’s accuracy also revealed that the maximum likelihood classification method did better in mapping the different forest cover types in the study area than the other two methods. spectral angle mapper relatively has poorer performance in mapping various categories of forest cover. this result is not in divergence with that found by mohd (2007) who used the same methods in mapping malayan tropical forest. the variation in the classification accuracies however might have been due to the method of training the classifier. this is because all the three methods have different approaches in selecting the training samples for the classification and this may have an influence on the classification accuracies. according to lillesand and kiefer (2000), the classification accuracies of any land cover maps will depend largely on the quality of the training set used. so any variation in training sample selection is likely to influence the classification results. the superior performance of the maximum likelihood classifier over the others may be due to the thorough examination of the spectral signatures separability of the different forest stand types in the area using the spectral feature space curve. difficulty in determining the precise dn values for the various forests stand types due to the spectral heterogeneity of their reflectance may have caused the decision tree classifier to have performed below standard. the performance of sam however showed that more than the direction of a vector is required in order to separate the tropical forest stand types, which are spectrally difficult to separate. in terms of technical simplicity and accessibility, the maximum likelihood classifier has been used for many years and is one of the inbuilt extensions of many gis and rs based software such as ilwis, envi, and erdas etc. spectral angle mapper and decision tree classifiers are restricted to specific image analysis software such as envi. execution of maximum likelihood classification technique is also straight forward and simple. thus its implementation is less laborious and requires relatively low technical know-how before execution. on the other hand, spectral angle mapper and decision tree techniques are more complex, time consuming and require expert knowledge in signature derivation and decision rule setting before final classification is attempted. the maximum likelihood classification method even though the oldest and traditional method, still may be considered to be the suitable method for mapping forest stand types in the study area than the other two methods especially when medium resolution images are employed. conclusions and recommendations the classification accuracy of the three classifiers was used as the determining factor for identifying the suitable mapping method. from the finding of this work, it may be concluded that the maximum likelihood classification method is a suitable method in mapping the different forest stand types in the area in comparison with the other two methods. in a nutshell, we may conclude that using maximum likelihood classifier and medium resolution imagery (aster), different forest stand types can be accurately mapped with an overall accuracy of 88.50% in the study area. with regard to mapping forest stand types in the study area, the maximum likelihood classification method is recommended because of its high accuracy, technically simplicity and being available in many remote sensing data analysis softwares. references abeney ea, owusu jgk (1999). workshop for media personnel on forestry and wildlife reporting proceedings, institute of renewable natural resources, ust, ghana, p. 95. blay d, appiah m, damnyag l, dwomoh kf, ari plo (2007). involving local farmers in rehabilitation of degraded tropical forests: some lessons from ghana. blay d (2004). rehabilitation of degraded forests through the collaboration of local communities in the dormaa district of brong ahafo region of ghana, pp. 31–35. campbell jb (2002). introduction to remote sensing. the guilford press chia j, caccetta pa, furby sl, wallace jf (2005). mathematical and information sciences, private bag 5 po wembley western australia 6913. congalton rg, green k (1999). assessing the accuracy of remotely sensed data: principles and practices. boca raton: lewis publishers. curran pj (1985). principles of remote sensing. longman scientific and technical group, essex, england. de carvalho lmt, clevers jgpw, skidmore ak, jong sm (2004). selection of imagery data and classifiers for mapping brazilian semideciduous atlantic forests. dees m, asan u, yesil a (2003). ideas and options for a national forest inventory for turkey. advances in forest inventory for sustainable forest management and biodiversity. kluver academic publishers, for. sci. pp. 375-395. fao (2000). global forest resources assessment main report. fao forestry paper, pp. 140,479. franklin se (2001). remote sensing for sustainable forest management. crc press, p. 7. ghana statistical service (2000). summary of the 2000 population census report. accra; ghana: ghana statistical service. huggins nj (2006). remote sensing classification methods for monitoring eastern red cedar. msc. thesis, missouri state university. hussin a, atmopawiro vp (2004). sub-pixel and maximum likelihood classification of landsat etm+ images for detecting illegal logging and mapping tropical rain forest cover types in berau, east kalimantan, indonesia. the international institute for geoinformation science and earth observation (itc), enschede, netherlands. jia x, richards ja (2006). remote sensing digital image analysis, an introduction, taylor and industrial arts. jensen me, everett r (1994). an overview of ecosystems management principles. ecosystem management principles and applications, eastside forest ecosystem health assessment, usda forest service, pacific northwest research station, general technical report. pnw-gtr-318. lillesand tm, kiefer rw (2000). remote sensing and image interpretation (4th ed.). new york: john wiley and sons. lemenih m, teketay d (2004b). restoration of native forest flora under plantation forests established on abandoned degraded agricultural sites in ethiopia. environ. manage. mlf (2004). criteria and indicators for sustainable management of natural tropical forests. ghana. mohd shz (2007). remote sensing & gis programme, dept. of civil eng., upm, 43400 selangor, malaysia. mongabay.com (2006). forest protection could earn tens of millions for ghana http://news.mongabay.com/2006/1106-ghana.html. pal m, mather pm (2003). an assessment of effectiveness of decision tree methods for land cover classification, remote sens. environ., 86: 554-565 richards ja (1993). remote sensing digital image analysis: an introduction. springer-verlag, berlin. song c, woodcock ce (2002). the spatial manifestation of forest succession in optical imagery. the potential of multi-resolution imagery, remote sensing environ., 82: 271-284. stehman sv, czaplewski lr (1998). design and analysis of thematic map accuracy assessment: fundamental principles. remote sensing environ., 64: 331-344. ted (1997). ghana forest loss. case studies http://www.american.edu/ted/ghana. htm in ternationa l scholars journa ls african journal of environmental economics and management issn 2375-0707 vol. 6 (1), pp. 367-373, january, 2018. available online at www.internationalscholarsjournals.org © international scholars journals author(s) retain the copyright of this article. full length research paper a study of the effect of traditional values and conservation of natural resources in nigeria *agbofuodoh ezekiel, onuoha elizabeth and arugbeni micheal department of environmental science, federal university of petroleum resources, p. m. b. 1221, effurun, nigeria. accepted 12 june, 2017 the role of traditional beliefs systems in the conservation of natural resources in some selected communities in delta state, nigeria, have been studied. methodology of study involves the use of personal interview, literature review, group discussion, and site visitation carried out by the authors between april 2011 and march 2012. findings show that traditional natural resources management in the selected communities are classified into the following categories: protection of particular ecosystems or habitats (such as sacred groves and sacred rivers/pond); and protection of particular animals or plant species (such as totem and tabooed species). the practices concerned relate to trees, forests, wildlife and marine organisms. the environmental wisdom and ethics expressed through these religious beliefs are very useful tools in natural resource management. using the classification of the international union of conservation of nature (iucn), the plants and animals species in the study scared groves and forest can be described as an environment with widespread and abundant taxonomy and are not at risk or endangered. key words: forest, sacred groves, traditional beliefs, biodiversity conservation, natural resources management, totems. introduction conservation of natural resources is the wise use of the genetic, species, and ecosystem diversity in the natural earth's resources by humanity. it is the management of abundance in which they occur. thomas (2003) sees valuable natural resources such as timber, fish, topsoil, *corresponding author. e-mail: dr.agboziel@yahoo.com conservation as the sacrifice of immediate rewards in pastureland, and minerals, forests, wildlife, parkland, return for delayed ones. smith and wishnie (2000) de wilderness and watershed areas. there are several fined conservation as actions that prevent or mitigate definitions of the concept – conservation, some stressing biodiversity loss and are designed to do so. in time past, the structural roots of anthropologist interests, others local people have developed a variety of resource arguing from the point of view of economic reasons. management practices that continue to exist in tropical usher (2000) defined conservation as the maintenance of africa, asia, south america and other parts of the world (appiah-opoku, 2007). agbofuodoh et al. 368 one of such approach is the use of traditional methods that have helped them to regulate interactions with their natural environment. the role of traditional beliefs in the conservation of a large number of elements of local biodiversity, regardless of their use value, dates back to creation (berkes et al., 2000; turner et al., 2000; shastri et al., 2002). traditional conservation ethics are capable of protecting biodiversity species in particular and the environment in general as long as the local communities have a stake in it. in fact, traditional ecological knowledge (tek) systems are infused with practices and concepts, and modes of teaching and learning that can be related directly and indirectly to resource stewardship and conservation at various scales. however, despite considerable attention directed towards documentation of these systems and approaches to conservation, we still have a limited understanding about their development, evolution, and transmission over time and space. chacon (2012) and krech (2005) have pointed out that the existence of traditional beliefs/taboos does not guarantee sustainable harvest of natural resources. traditional african religion (atr) and cultural practices as done in most part of african communities are environmentally friendly and sustainable, thus contributing so much to natural resources sustainability and conservation (international institute for environment and development, 1992). in africa and indeed nigeria, the traditional belief system holds the ascription of supernatural powers to objects called gods and goddesses. the major tenet of african traditional religion and belief system lies in the belief that the abode of the gods and goddesses is located on rock, streams, pond, tress, land or anywhere they so desire to live within the community. the gods choose their followers through the rites of initiation with a core messenger who is the mouth piece of the gods living among human beings. the gods or goddess communicate its will to the people through the juju priest or chief priest. the belief system is that the gods protect the community members from harm, famine, bareness, impotence, drought, epidemics and war among others. the gods avenge their anger on whoever omits or commits any flaw for which their presence forbids; hence, the cultural system holds to a very high esteem all the precepts of the laws of the gods (shastri et al., 2002). these beliefs and strategies are passed on to those who become initiated into adulthood in the community during the rites of initiation. most often, it is the men that are always initiated into these community cults or sects which are often enshrined in religious or cultural beliefs and superstitions and enforced by taboos. the taboos and beliefs have legal backing in the rules and institutions of the communities which are strong enough to make people obey the religious and cultural regulations (venkataraman, 2000; cox, 2000). the role of traditional beliefs in the protection of natural resources is reflected in a variety of practices including sacred groves and sacred landscapes. for example, in india, particular patches of forests are designated as sacred groves under customary law and are protected from any product extraction by the community. such forests are very rich in biological diversity and harbour many endangered plant species including rare herbs and medicinal plants. tiwari et al. (1998) identified 79 sacred groves and their floristic survey revealed that these sacred groves are home to at least 514 species representing 340 genera and 131 families. about 1.3% of total sacred grove area was undisturbed, 42.1% had relatively dense forest, 26.3% had sparse canopy cover, and 30.3% had open forest. notably, the species diversity indices were higher for the sacred grove than for the disturbed forest. study on two sacred groves, oorani and olagapuram, situated on the north-west of pondicherry found a total of 169 angiosperms from both sites. the oorani grove (3.2 ha) had 74 flowering plant species distributed in 71 genera and 41 families; 30 of them are woody species, 8 are lianas and 4 are parasites. the olagapuram grove (2.8 ha) was more species-rich with 136 species in 121 genera of 58 families; woody species were fewer (21) while 9 lianas and 3 parasites occurred (ramanujam and kadamban, 2001). the traditional conservation of non human primates by iban forest farmers in west kalimantan, indonesia, is an important part of their subsistence economy, and as such aided the promotion of certain aspects of the traditional iban agroforestry system (wadley et al., 1997; wadley and colfer, 2004). in a research on traditional and indigenous methods of conserving biodiversity, ntiamoa-baidu (1991) identified three indigenous methods for conserving biodiversity in ghana and other west african sub region (nigeria inclusive). the tribal communities of urhobos in delta central – have a tradition of environmental conservation based on various religious beliefs. an essential feature of urhobos in the conservation of natural resources is totemism (the belief in a supernatural connection between a group of people and a group of objects like certain animal species, sometimes plants, or more rarely other objects). usually, it is a taboo to kill or eat an animal totem (tonukari, 2007). social taboos exist in invariably all cultures throughout the world, and represent a class of informal institutions, where traditional, religiously governed norms or taboo system define the human behaviour. these taboos remain the prime factor guiding their conduct towards the exploitation of the natural resources. however, the singular role played by these informal systems of taboo in conservation of biodiversity has not been given its due importance. the present paper attempts to render forth the salient aspect of conservation borne out of the taboo system in practice surrounding the sacred natural sites, principally the sacred forests, in some communities of delta state, nigeria. the vital roles of beliefs, rituals and taboos in traditional natural resources management are emphasized. 369 afr. j. envir. econ. manage. figure 1. map of delta state showing the local government areas. materials and methods study area delta sate is one of the 36 states of the federal republic of nigeria comprising mainly igbo, urhobo, isoko, ijaw and itsekiri ethnic nationalities. the whole ethnic-groups that comprise the delta are administratively grouped into three senatorial districts namely delta north, delta south and delta central for administrative purposes. the state presently covers a landmass of about 18,050 km 2 of which more than 60% is land. the state lie approximately between longitude 5° 00 and 6°45' east and latitude 5° 00 and 6° 30' north. it is bounded in the north by edo state, the east by anambra state, south-east by bayelsa state, and on the southern flank is the bight of benin which covers about 160 km of the state's coastline. delta state is generally low-lying without remarkable hills. the state has a wide coastal belt inter-lace with rivulets and streams, which form part of the niger-delta. the physiographic and ecological zones found in delta state range from the relative high of the asaba plateau through the low wetlands and swamp forests that occupy almost the entire west and southwestern half of the state to the atlantic coastline. while the high northeast is sparsely drained, the wetlands are crisscrossed by numerous perennial streams. this diversity in ecosystems requires careful management with policies that specifically address these systems. in addition, the entire state falls within the niger delta petroleum province. petroleum exploration and production is gradually moving northwards from the south where the industry has been thriving for more than fifty years. pipelines and flow stations abound. in light of the foregoing, it has become necessary to undertake the production of guideline with the specific purpose of protecting delta state ecological environment especially the marine ecosystems. delta state is made up of twenty-five local government areas (figure 1). the method of data collection and fact used in this research is personal interview, literature review, group discussion, and site visitation carried out by the authors between april 2010 and march 2011. the method of study is consistent with that reported in literature (chambers, 1983, 1994). a total of 9 communities were purposefully selected and visited for the study. the choice of the selected communities is based on the fact that these communities have established religious and cultural practices already as was revealed in the course of literature review. the communities are located within the following local government areas: ukwani, ethiope east, ughelli south, ndokwa east and ughelli north (figure 1). the communities studied were umuaja, orogun, useifurun, ode-itsekiri, okorobi, ase, ovu inland, orohoakpor and ujevwu. some traditional and cultural practices are similar, with the same name in some communities, so there was no need repeating the same story, so such traditions were recorded for only one community. the findings from the field were documented and their implication discussed with our interviewees in the various communities in delta state. findings at useifrun and ujevwu communities in ughelli south and udu local government areas, respectively, the python is regarded as a totem. ancient legendry has it that during inter tribal wars; the python goes after the people and erases their footprint so that enemies would not identify the pathway of the people. this is similar to that reported in the worship of python in west bengal kingdom where there was evidence that the reptile was associated with success in war (deb and malhotra, 2001). in gratitude, none of the people of west bengal heritage whose ancestors were thus saved, kills or eats the python to this day, the people of useifurun and ujevwu communities believe that the snake itself is not worshiped, but rather its indwelling spirit. in the studied communities, there is a dedicated temple where sacrifices are offered to the snake god. the python house can be described as a rectangular hut of clay painted with white colouring substances and covered by a thatched roof. the priesthood is hereditary, and the chief priest is agbofuodoh et al. 370 head of the system. there are snake wives; these are beautiful women that the snake consistently appears to physically and spiritually. on the day of initiation into the temple, the priest, dressed in a ceremonial robe, drinks from the bowl of the python, then hands over to the woman of concern to also drink from. the spirit of the python goes into the medium (the woman) who wriggles on the floor like a snake, uttering strange sounds and talking in a language which has to be interpreted to the worshipers, she is then admitted in the service of the snake god. the snake is a symbol of their annual festival where every member of the community was allowed to take part in the revelry, which included dancing, feasting and singing. the python god is the god of wisdom, earthly bliss and benefaction. it is the principal object of ancestral adoration. in these communities, the killing of python is an abominable act, so they are held sacrosanct. snakes are free to wander, but the priest may retrieve them. a native who meets a python says, "you are my father and my mother." the native then cries to the god, "my head belongs to you, be propitious to me." very seldom is a human being attacked by a python, but, if such an event happens, the priest is the only one who may effect a rescue. no one dared harm the reptile; on the contrary, it must be guarded and fed. the population of the reptile in the communities is high and is fast becoming a source of concern. the findings of the study are consistent with that reported in west bengal and ashati (deb and malhotra, 2001; eneji et al., 2009; international institute for environment and development, 1992). at orhoakpor in ethiope – east local government area, the mighty okpagha tree is highly revered. the okpagha and ogriki trees have had a conspicuous position in the cultural landscape of the people. the okpagha tree is said to belong to aziza spirit. it is believed that the aziza spirit himself found enlightenment under okpagha tree. aziza is essentially considered by the people as a deity of the woods, whose province is to guard the fields, crops and herds of the peasantry and to drive away their enemies. the location of the tree is regarded as a sacred place where trees and plants were allowed to grow undisturbed and where reptiles, birds and animals could have free living without fear of poaching or interference by man. groves of this tree are sacred and hence no axe may be laid to any tree, no branch broken, no firewood gathered, no grass burnt; and wild animals which have taken refuge there may not be molested. at the bottom part of the tree, cocks, sheep and goats are sacrificed and prayers are offered for rain or fine weather or on behalf of sick children. in addition, a number of the juju priests have their powers associated with the aziza spirit. at the time of the study, the location of okpagha tree provided excellent sites for examining the vegetation that had existed a century earlier, as several species of plants and birds that are rare were sighted. although, the plant is strictly protected in the community; however, religious use of this resource is allowed. wood from the sacred tree is believed to keep its magical powers when fashioned into other objects and was used for making a variety of objects like statues of gods, staffs, sceptres, etc. the bark of the plant is reported to be very medicinal and is efficacy is in the treatment of strange illness. at ovu inland in ethiope – east local government area is the ovughere (village deity) that is highly regarded as the god of war. the chief priest of the village diety is the osedjo whose office is hereditary. the abode of the ovughere is located within a very thick forest with presence of trees such as iroko tree, mahogany trees, ogriki etc. according to oral literature, these trees are well over seventy years. the forest is the property of the god of the village in which they are situated, and the trees ought not to be cut. location of residential settlements close to the shrine is not permitted thus checking defo-restation and farming and thereby protecting the surroun-ding vegetation. this factor promotes the conservation of biodiversity in sacred grove through selective limits or prohibitions on the use of biotic species. secondly, infor-mation such as about species of ritual, medicinal or commercial value are kept secret from outsiders. this finding is consistent with that reported in traditional afri-can societies where many people believed that trees and forests were the manifestation of the power of the supreme being (eneji et al., 2009). while the area occu-pied by the forest may be a relatively small, the level of biodiversity is high and thus is of some environmental significance to the community people. at okorobi village in ethiope east local government area, is the “obi” pond popularly called obi lake. it is the main source of water for drinking and domestic purposes in the community. it is believed that the obi spirit inhabits the water body. harvesting of fish here is strictly prohibited, but when fish leaves this lake to the surrounding environment, harvesting can be done there. there is also the traditional obi cult in the community with a juju priest in charge of offering sacrifices to the obi god. usually, membership into this group is on strict qualification with terms and condition of membership strictly spelt out and passed down to community members for onward transmission to their children while growing up. most often, the process of initiation is a transitive one, from adolescent to adulthood and done in the night deep inside the shire. felling of trees or fuel wood collection within 30 m radius from the pond is strictly prohibited. these principles though unknown was meant to preserve the watershed and the surrounding vegetation, this consequently checks the amount of evapotranspiration and allows some amount of tolerable water temperature for both micro and aquatic organisms to continue their ecosystem services for the enrichment of the soil, continuous supply of water and the healthy growth of the forest. the vegetation cover also helped to keep the water cool and fresh for drinking. bathing and washing of clothes around, near or inside the pond where drinking water is fetched is not allowed; also fishing or harvesting any aquatic animals within the pond is as well prohibited. reasons abound for this law, spanning from the respect for the obi god who protect the pond and the organisms helping to purifying the pond and keeping the pond alive and also control the spread of diseases. silence is observed while fetching water from the pond because it is believed that while speaking, an infected person may spill or splash saliva. for instance, an infected person with tuberculosis or whooping cough spill infected saliva containing bacteria in the water. in addition, this rule ensured the gods were not provoked to anger. their anger could result to streams or rivers drying up. other taboos, such as the disallowing of menstruating women to collect water from the pond, prevent the defilement of pond deity and god and the issue of menstrual blood in traditional beliefs has been treated extensively in anthropology as a source of potent force (mcleod, 1981). in ase village in ndokwa east local government area, the “usede” pond is a mysterious pond harvested for fish species by the entire ase kingdom once in ten years. the only species of fish harvested, brought together and shared together by everybody present is the mudfish; any other species of fish caught during this day is owned by whoever catches it during the harvesting period. the usede pond is such that nobody goes there to fish alone within this period of ten years, if violated the punishment begins by having a bloated stomach and later death no matter the sacrifice made. however, entrant into the pond alone is frightening. community harvesting of the pond is usually carried out in the dry season and two peculiar events happens in the course of the harvesting. first, is the heavy rainfall that precedes harvesting of fish from the usede pond showing that the spirit of the gods and the living are in tandem. secondly, is the appearance of a big fish with a string of cowry that signifies the end of the fishing festival, the big fish with a string of cowry will come through where the people are harvesting the fish, once the mother fish with the cowries is sighted by anybody, the harvesting must stop and everybody inside the pond must be called out of the pond. although, species diversity in the water body have not been documented; it is believed that the pond is rich with different species of fish. in ode itsekiri in warri – south local government area, there is an evil forest within the mangrove swamp forest where “dead bad people” are thrown into. the dead bad people may include those that have confessed to the act of witchcraft (male and female inclusive), dead by suicide, dead by cancerous wound, dead resulting from falling from a tree or palm tree, and a pregnant dead woman. in addition, when a person dies as a result of mysterious sickness and did not confess to any act of evil doing, the oracles are consulted to inquire into the cause of this death. if the deceased was not a "good citizen" often the corpse is thrown into this forest. this is done to 371 afr. j. envir. econ. manage. prevent the reincarnation of such spirit. while this is so, the number of wild beast that lives within this area is awesome. no human activity of any kind is carried out in the evil forest as it is belief that the spirit will not take it kindly with anybody disturbing the peace of the dead or the spirits themselves. so, the area remains a very thick forest habiting a number of species of different organisms. this observation is consistent with that reported in the eastern part of nigeria (ogbuagu, 2011). for the urhobos, death can happen because of old age, witchcraft, accident or illness and abomination. but, generally speaking, the urhobos think that there are only two kind of deaths – good death and bad death. good death is associated with people who are of age 70 or more, who had a moral life and are not members of some secret cult. the urhobo people believe that burial rites and ceremonies are needed because without them the spirit of the deceased will not be able to join the ancestral spirit. good people are buried in a traditional ritual to the ancestors and gods of the land. there are prayers for the dead to protect and bless the living. a young person who died prematurely, but lived a morally right life is buried, but without passing on festivities and rituals. in the coffin of the deceased people, some “weapons” such as cutlass, knife, broken bottle etc are placed inside. it is believed that these objects should help him/her to fight and avenge his/her death. the urhobos believe that young people cannot die. for them these deaths are caused by someone who killed them. people who died without children are buried, but with no festivities and other rituals. the reason for this is that they do not have children, who will continue to have their name and perform the ancestral worship (onigun, 1998). in orogun kingdom in ughelli – north local govern-ment area, the reptile iguana are found in large popula-tion and revered. the iguana is sacred animal to the orogun people who may not kill or eat it. the myth has it that orogun people were initially settled around the aboh area where they had problems with benin traders which resulted in the killing of the benin traders, fear of possible reprisal from the great ancient benin kingdom made them to move to their present location. in the course of such movement, on getting to riverside while escaping, they could not find their boats, but instead they saw what appeared as logs across the river, on which they crossed the river. upon successfully crossing the river, they discovered that it was iguanas that formed a chain across the river for them to get to safety. that was how the iguana became a god and saviour for the orogun people. eating iguana by indigenes brings rashes to their body and the only cure to it is to go to erose shrine where you will be giving native chalk and sand from the shrine. the affected person will now use the sand and native chalk to robe his body for seven different orogun market days before the rashes can be cured. today, the population of iguanas is very high as the animal is allowed into homes where they are well fed. at the death of an iguana, an agbofuodoh et al. 372 orogun indigene gives it a befitting burial. at umuaja, in ukwani local government area, is the origin of river ethiope where water is seen to come out from underground through roots of a very big tree. the tree is regarded as sacred grove and an abode of gods. spiritual activities at the sacred grove are controlled by chief priest who is in charge of the abode of such god and who also is the messenger of the god in human form. the source of the river, is also revered and protected because it is regarded as the source of life and fertility; barren women go to bathe in these waters in the hope of being fertile. the river and their immediate surroundings, especially forest are protected on the basis that the spirit of the river resided in the area. the responsibility for protecting the grove is vested in the entire community, but a selected group of people or family normally takes the duty to enforce the rules. the conservation strategy, which is one of preservation, is enshrined in taboos, totems and sacrileges and other numerous cultural and religious rites and is maintained through reverence for the gods and ancestral spirits. these traditional guards regularly patrol the periphery of the grove and arrest intruders, who are reported to the chief priest for the necessary customary sanctions. the sanctions, which are done for the purpose of pacifying and purifying the gods and spirits, vary depending on the gravity of the offense. however, they usually consist of a cash fine, bottles of hot drinks, goats, sheep, chicken, kola nuts and alligator pepper as sacrifice to the gods. action that attracts the wraths of the god includes: i) felling of trees or fuel wood collection within 20 m radius from the area is strictly prohibited. this principles though unknown was meant to preserve the watershed and the surrounding vegetation, this consequently checks the amount of evapotranspiration and allows some amount of tolerable water temperature for both micro and aquatic organisms to continue their ecosystem services for the enrichment of the soil, continuous supply of water and the healthy growth of the forest. the vegetation cover also helped to keep the water cool and fresh for drinking. this system protects the watershed from destruction; ii) bathing and washing of clothes around, near or inside the source of the river where drinking water is fetched was not allowed; iii) fishing or harvesting any aquatic animals within the source of the river is not allowed. this sacred grove survived all these while purely because of the strong religious / cultural beliefs held by the local people and the spiritual, religious and cultural attachments to the grove. the major virtue of this strong culture-based practice is that it encourages community participation in natural resource conservation and sustains positive awareness of nature and the linkages between man and nature (tunon and bruhn, 1994; tupper, 2002). this tradition has been used to protect the headwaters of several river bodies, especially those that served as potable water sources for a community or group of communities (falconer, 1992). the river ethiope watershed may be small in size but it is of biological significance, and a potential for biodiversity conservation. conservation status of plants and animals species as noted previously, traditional natural resources management is shaped around local rules and regulations. these rules and regulations are most often enshrined in religious or cultural beliefs and superstitions and enforced by prohibitions. these have no legal backing, but the beliefs have been strong enough in the past to make people obey the regulations. in the context of natural resources management, they enhance biodiversity con-servation and minimize the continuous use of natural resources. the conservation status of most of the species of plants and animals found in the studied areas was assessed using the international union of conserva-tion of nature (iucn) red list of threatened species (also known as the iucn red list or red data list). the iucn is the world's main authority on the conservation status of global conservation status of biological species. the iucn red list is set upon precise criteria to evaluate the extinction risk of thousands of species and subspecies. these criteria are relevant to all species and all regions of the world. the aim is to convey the urgency of con-servation issues to the public and policy makers, as well as help the international community to try to reduce species extinction. according to iucn (1996), the for-mally stated goals of the red list are: 1) to provide scientifically based information on the status of species and subspecies at a global level, 2) to draw attention to the magnitude and importance of threatened biodiversity, 3) to influence national and international policy and decisionmaking, and 4) to provide information to guide actions to conserve biological diversity. species are classified by the iucn red list into nine groups, set through criteria such as rate of decline, population size, area of geographic distribution, and degree of population and distribution fragmentation. i) extinct (ex) – no known individuals remaining. ii) extinct in the wild (ew) – known only to survive in captivity, or as a naturalized population outside its historic range. iii) critically endangered (cr) – extremely high risk of extinction in the wild. iv) endangered (en) – high risk of extinction in the wild. v) vulnerable (vu) – high risk of endangerment in the wild. vi) near threatened (nt) – likely to become endangered in the near future. vii) least concern (lc) – lowest risk; does not qualify for a more at risk category. widespread and abundant taxa are included in this category. viii) data deficient (dd) – not enough data to make an assessment of its risk of extinction. ix) not evaluated (ne) – has not yet been evaluated against the criteria. using the classification of the international union of conservation of nature (iucn) red list of threatened species (also known as the iucn red list or red data list), the plants and animals species in the study scared groves can be described as an environment with widespread and abundant taxonomy. plants and animals species are at a very low risk as a result of culture and traditional beliefs systems. plants and animals species are not endangered. conclusion from the very on-set, the paper aims at looking at the roles african traditional religion and socio-cultural practices can play in the management of natural resources. findings indicate that traditional religion and cultural practices have contributed in the conservation of resources through the ascription of psychic powers to object, rock, stream/pond, tree, forest land etc; these ascriptions of the supreme powers and the belief and respect for the gods of the land holds the string to reverence and respect for these objects. this belief in the existence of a supreme being responsible for the protection of the communities has also enabled the traditional african communities to voluntarily take management of natural resources very seriously. the traditional beliefs and taboos helped in enforcing rules and regulations for environmental preservation because people 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(2000). traditional ecological knowledge in environmental assessment and management. arctic, 53(2):183-193. venkataraman a (2000). incorporating traditional coexistence propensities into management of wildlife habitats in india. curr. sci. 79:1531-1535. wadlley rc, colfer c, hood i (1997). hunting primates and managing forests: the case of iban farmers in indonesioan borneo. hum. ecol. 25(2):243-271. wadley rl, colfer cjp (2004). sacred forest, hunting, and conservation in west kalimantan, indonesia. hum. ecol. 32:313–338. in ternationa l scholars journa ls african journal of environmental economics and management issn 2375-0707 vol. 7 (7), pp. 001-010, july, 2019. available online at www.internationalscholarsjournals.org © international scholars journals author(s) retain the copyright of this article. full length research paper the perfect drought? constraints limiting kalahari agro-pastoral communities from coping and adapting k. mogotsi1*, m. m. nyangito2 and d. m. nyariki2 1 department of agricultural research, animal production and range research division, p. o. box 10275, francistown, botswana. 2 department of land resource management and agricultural technology, university of nairobi, p. o. box 29053, nairobi, kenya. accepted 31 january, 2019 rural kalahari agro-pastoral communities of southern africa have been exposed to drought shocks throughout history and have adapted their livelihoods accordingly. yet, drought continues to disrupt or threaten to disrupt their production systems. with semi arid botswana as a case study, this paper hence sought to unearth the factors limiting agro-pastoral communities from adequately coping and adapting to drought. low rainfall, which is also highly variable, coupled with relatively low soil fertility status make subsistence livestock keeping and crop cultivation risky. this marginal agricultural potential of the land is further compounded by other constraints. some of the major constraints included persistence of droughts, limited diversification options outside agriculture, inadequate and poor quality drinking water (high salinity) for livestock, crop damage by wild animals as well as the current land tenure system which curtails the traditional response of livestock mobility during drought. all these factors may act solely or in combination to render rural communities vulnerable during droughts. it is therefore recommended that effective interventions be tailored to local conditions to enhance resilience among kalahari’s rural population. key words: adaptation, botswana, coping, drought, variability, vulnerability. introduction droughts are common phenomena in many parts of southern africa. not only is the region drought-prone, but the rural communities inhabiting these areas are well aware of the adverse effects of droughts on their environmentdependent livelihoods. smallholder farmers, who are the most likely to experience disruptions to their production efforts, are even more vulnerable during droughts. this increasingly becomes vivid with extended periods of droughts, when crop failure and livestock mortalities peak. this exposure to drought hazards has necessitated responses involving a myriad of coping and adaptive strategies among the communities (owens et al., 2003; enfors and gordon, 2008; eriksen and silva, 2009). and although droughts may be geographically localised, their non structural effects, which may spread to other sectors of the economy have even prompted action from national governments in the region (sadc, *corresponding author. e-mail: kbmogotsi@yahoo.com. 1999; fao, 2004). coping and adaptation,both distinct but intricately related processes (adger, 1996), have drawn widespread attention over the years especially with the compounded threat of climate change, perhaps the most overriding issue of our time. but despite the significant research effort aimed at understanding the physical aspects of droughts and the effects thereof, as well as the attendant coping and adaptation mechanisms, agro-pastoral communities still continue to struggle to increase production and/or sustain their livelihoods in the semi arid environment of southern africa. what then, could we be missing in our efforts? could there be a crack in the armour, so to speak? frankenberger (1992) argues that, over the years, environmental degradation (for example through overgrazing and deforestation) and lack of water conservation measures may have served to further exacerbate the effects of droughts. other researchers (fako and molamu, 1995) have argued that poverty may be the underlying problem. according to fao (2004), it is generally acknowledged that lowresource agriculture is unable to sustain livelihoods in these fragile semi arid environments. this study therefore set out to identify the main factors limiting households in the kalahari from adequately coping and adapting to droughts, with botswana’s subsistence agro-pastoralists as a case study. understanding the prevailing conditions, as seen by the farmers, could inform policy makers and launch better-coordinated intervention programmes to enhance farmers’ resilience to future drought shocks, which are generally expected to increase in the region (reed et al., 2007). methodology study areas kgalagadi north is part of kgalagadi (kalahari) desert ecosystem, the driest district in botswana and the least inhabited. the highly variable and erratic rainfall regime characterizes the area, with an average of about 350 mm annually (bhalotra, 1985). rainfall follows a uni-modal pattern, falling mainly between october to april. maximum summer temperatures (october to april) average 41°c in january and february and a mean minimum for august of -8°c in winter months (may to september). thus evapo-transpiration rates are quite high, exceeding precipitation by more than a factor of three (chanda et al., 2003) and resulting in the absence of surface water for most times of the year. the soils of the area are arenosols (fao, 1991). the vegetation type is southern kalahari bush savanna (skarpe, 1986). the main perennial grasses include stipagrostis uniplumis, eragrostis lehmanniana, schmidtia pappophoroides and aristida meridionalis. annual grasses include schmidtia kalahariensis and aristida congesta. woody species include acacia erioloba, acacia leuderitzii, acacia mellifera, boscia albitrunca, grewia species, dichrostachys cinerea, ziziphus mucronata and terminalia sericea. the other study site was in the bobonong region within the central district. temperatures above 33ºc are common in summers, and they sometimes decline to 4ºc in winters. long-term rainfall averages 350 mm per annum and occurs mostly in october to april. the main soil type is eutric regosols and in some areas petric calcisols/chromic luvisols (fao, 1991). the vegetation consists of tree savanna and acacia shrub savanna (weare and yalala, 1971). woody species include colophospermum mopane, combretum species, grewia flava, acacia tortillis, dichrostachys cineria and commiphora species. the major grass species are s. uniplumis, eragrostis rigidior, digitaria eriantha, aristida congesta and urochloa species. various species of forbs are found. agriculture is the main source of livelihood of the rural communities in both study areas. pastoral farming is dominated by traditional production systems within communal grazing areas termed cattleposts or ‘meraka’. subsistence crop cultivation is practiced but to a lesser extent compared to livestock keeping. data collection rainfall the long-term annual rainfall data for the study areas were sourced from the department of meteorological services. for the bobonong sub-district, the bobonong field station was used while the tshane station was used for the kgalagadi north study area. the data for both sites were from 1959 to 2009, totalling 50 years. soil soil sampling was done once during the study period at sampling points on randomly-placed line transects. three 5 km line transects were set up along a representative grazing area in each study site. topsoil cores (0 to 7.5 cm) were taken at 1 km intervals and the soils were analyzed for chemical properties at the soil and plant analytical laboratory in sebele, botswana. exchangeable bases calcium (ca), magnesium (mg) and potassium (k) were determined using ammonium acetate as described by thomas (1982). the walkley and black method (walkley, 1935) was used to determine the organic carbon (oc) content in the soil samples, while the bray ii method (bray and kurtz, 1945) was followed in determining phosphorous (p) amounts. in addition soil ph was determined. vegetation vegetation analyses included density, species composition and frequency and herbaceous cover using the quadrat method (cook and stubbendieck, 1986). for important woody browse species, the point-centred quarter (pcq) method was used to determine their density, along the same line transects, following browser and zar (1984) and cook and stubbendieck (1986). social data collection the agro-pastoral households 1 were selected at random with the input of the extension officers from the ministry of agriculture in the respective areas. in the bobonong sub-district (lepokole and surrounding communal areas of sekgopswe, mmamanaka and mmaditshwene), 50 households were interviewed while 38 were interviewed in kgalagadi north (hukuntsi, lehututu and tshane villages). the survey collected information on demographic characteristics, socioeconomic status (e.g. income sources), land tenure, crop and livestock management, input use, access to information, extension, technology, markets and credit as well as constraints to coping and adaptation efforts. data triangulation was done through participatory rural appraisal and key informant interviews in each study area. statistical analysis data were subjected to the statistical package for social sciences (spss). frequencies were calculated using descriptive statistics for respondent demographics, socio-economic characteristics and related variables. a one way analysis of variance (anova) was carried out for soil chemical properties between the two study sites. where significant differences existed (p < 0.05), tukey’s hsd was used for means separation. the same procedure was used with vegetation data (percentage cover and density). the density of important woody species was determined as described by browser and zar (1984) and cook and stubbendieck (1986). results and discussion biophysical characteristics rainfall the semi arid environment of botswana exhibit erratic and variable rainfall regimes, both spatially and 1 following niehof (2004), a household herein refers to a family-based coresidential unit that takes care of resource management and the primary needs of its members. annual rainfall long term rainfall mean figure 1. rainfall pattern and long term mean for bobonong (bobonong sub-district). gaps in graph indicate missing data. temporally. the study sites showed such trends for a period exceeding 30 years (figures 1 and 2), with no distinct pattern-further underlining the unpredictable nature of rainfall. the high variability in rainfall (44 and 41% coefficients of variation for bobonong (bobonong sub-district) and tshane (kgalagadi north sub-district) respectively 2 ) has implications for the rural communities dependent on rainfed agriculture for subsistence. dry extremes are common. even in non-drought years, crop cultivation is a risky undertaking. seasonal non-availability of surface water and deterioration of forage for livestock results in reduced productivity and at times of extended droughts, possible livestock deaths. soil chemical properties the important chemical properties from the two study sites are as summarized in table 1. the results of the analysis showed significant differences (p < 0.05) in magnesium (mg), cation exchange capacity (cec), organic carbon (oc) and phosphorous (p) levels between the two sites. the significantly higher cec of soils in bobonong could be attributed to the higher clay content found in the soils 2 cvs of 33% mark the critical value where non-equilibrium dynamics emerge (ellis, 1995). dominant in the area (fao, 1991), which generally also have better water holding capacity. the soil cec is important as it allows exchangeable cations such as mg, calcium (ca) and potassium (k) to be readily available for uptake by plants. in general, the higher the organic matter and clay content, the higher the cec (brady and weil, 2001). thus the low cec in kgalagadi north rangeland soils could partly be due to the low oc content of the soil (0.15%). apart from increasing soil water holding and cation exchange capacities, the organic fraction is important as it also serves as a reservoir for the plant essential nutrients and enhances soil aggregation and structure. phosphorus levels in kgalagadi north were significantly lower (p < 0.05) than in bobonong, further attesting to the poor fertility status of the kalahari sands. the vegetation would also likely be low in p. according to apru (1980), p levels in botswana grasses rarely exceed 1.0 /kg, thus farmers have to supplement their animals to avoid increased incidences of aphosphorosis (stiff sickness) due to consumption of poor grasses. animal manure is a common source of p especially in grazing areas, but chanda et al. (2003) note that due to the low rainfall amounts in kgalagadi, natural input of p is insignificant. also, p becomes less available for uptake by plants if soil ph is relatively low. the average ph values for kgalagadi north and bobonong sub-districts were 5.47 and 6.25, respectively. p is thus a limiting factor in the productivity of the kgalagadi north soils. the generally low soil annual rainfall long term rainfall mean figure 2. rainfall pattern and long-term mean for tshane (kgalagadi north sub-district). table 1. some soil chemical properties of the study sites. study site k ca mg cec oc (%) p (ppm) cmol/kg kgalagadi north 0.23±0.03 a 3.70±2.67 a 0.60±0.05 a 2.34±0.26 a 0.15±0.01 a 4.52±1.55 a bobonong 0.33±0.04 a 9.13±2.49 a 1.07±0.22 b 6.91±0.88 b 0.40±0.04 b 16.96±4.30 b column means with different superscripts are significantly different at p< 0.05. fertility findings of kgalagadi are echoed by perkins (1991), who attributes it partly to their sandy nature. so, based on the results, where kgalagadi north has significantly lower soil chemical properties than bobonong except for mg and ca, coupled with erratic and low rainfall in the area, one could conclude that costeffective arable farming would be a challenge for kgalagadi north rural communities. thus households dependent on crop cultivation and natural pastures for livestock are likely to be more vulnerable to droughts because of the low ecological productivity of the soils. vegetation characteristics plant frequency the frequencies of some important plant species found in the study sites are given in table 2. grasses of economic importance with regard to livestock production (apru 1976) such as eragrostis spp., urochloa spp. and digitaria spp. were encountered. aristida spp. on the other hand, was a key indicator of poor range condition together with the invasive forb elephantorrhiza elephantina which dominated in some grazing areas not far from water points in kgalagadi north. percentage herbaceous cover the percentage herbaceous cover for the two study sites is presented in table 3. there was a significant difference (p< 0.05) in cover between the two sites. the average cover for the herbaceous layer towards the end of the growing season in march was 61.78 and 76.67% for bobonong and kgalagadi north respectively, which is expected to be less during the dry winter season (may to august). this is especially so for bobonong area as the bulk of the herbaceous cover constituted of annual grasses and forbs. cover is important as it protects the soil layer from being exposed to elements of erosion. thus soils in bobonong area, because of lower percentage cover, are table 2. frequencies of selected important plant species in the study areas. plant species relative frequency (%) bobonong kgalagadi north perennial s. uniplumis 40 eragrostis spp. 24.4 27.78 digitaria spp. 4.44 8.89 enneapogon cencroides 6.67 annual aristida spp. 35.56 33.33 s. kalahariensis 20 urochloa trichopus 60 35.56 tragus spp. 22.22 13.33 s. pappophoroides 22.22 chloris virgata 22.22 melenis spp. 2.22 13.33 forb e. elephantina 33.33 other forbs 75.76 88.89 table 3. percentage cover of the herbaceous layer in the two study sites. study site herbaceous layer cover (%) bobonong 61.78±5.95 a kgalagadi north 76.67±3.57 b column mean with different superscripts are significantly different at p < 0.05. more prone to wind and water erosion. density of woody plant species the total densities for woody species in bobonong and kgalagadi north study sites averaged 790 and 345 plants/ha respectively (table 4), which was significantly different (p < 0.05). the most abundant woody species, based on relative densities, in bobonong sub-district were grewia species (28.89%), c. mopane (22.78%), a. tortilis (13.33%), combretum apiculatum (7.78%), d. cineria (7.22%) and commiphora species (5.56%). in kgalagadi north study site, grewia species (37.22%, especially g. flava), a. mellifera (19.44%), acacia erioloba (10.00%), terminalia sericea (10.56%), acacia luederitzii (8.33%) and boscia albitrunca (7.22%) dominated. the lower woody species density in kgalagadi is consistent with its classification as a bush savanna (skarpe, 1986), giving it an ‘open canopy’ look in contrast to the denser bobonong area. six (6) woody species were common to both areas. sorenson’s community similarity index showed that the two study areas were 37.5% similar in terms of woody plant species composition. woody species are especially important as browse (including pods) for livestock during the dry season (may to august) and drought periods. this stems primarily from the fact that although important livestock grasses decline drastically in both quantity and quality during the non-rainy period in botswana (apru, 1976), woody browse species can still provide enough nutrients for livestock maintenance requirements (moleele, 1998). but not all woody species are necessarily desirable. for example, in kgalagadi north area, the dominance of a. mellifera was more pronounced near water points (natural pans). moleele and mainah (2003) noted the same trend. the species is one of the thorny encroachers, and fraser et al. (2006) suggest that it thrives due to a combination of factorsnamely, intense grazing, drought and a reduction in frequency and intensity of natural fires. from the vegetation characteristics previously discussed, the herbaceous cover can be an important element in the agro-pastoral communities’ efforts to cope and adapt to drought shocks. however, the bulk of the herbaceous cover in bobonong area was annual grasses and forbs-offering a temporary resource base not available during the dry season and drought years for livestock to feed on. the transient nature of this resource leaves livestock susceptible to weight loss, emaciation and possible deaths, and thus threatening the livelihood base of the communities during droughts. on the other table 4. mean woody species densities and number per site. study site mean absolute density (plants/ha) number of woody species bobonong 789.67±101.60 a 20 kgalagadi north 345.33±27.95 b 12 column means with different superscripts are significantly different at p< 0.05. salary/wages old age pension scheme figure 3. main sources of income for households in kgalagadi north and bobonong sub-districts. hand, the palatable perennial grasses and woody plant species provide the nutritional requirements of livestock deep into the dry season and to some extent during droughts. thus, this first line of defence can be critical especially for poorer households heavily dependent on the natural resource base. socioeconomic characteristics of households main sources of income most of the surveyed households in both study areas had between 5 and 7 members each. households also had several sources of income (figure 3). in kgalagadi north, the majority of households had sales from agriculture, both crops and livestock, as their main source of income (57.9%). selling of livestock (especially cattle and goats) was done primarily on a subsistence basis-usually to buy food for the household, buy livestock feed, pay bride price (‘bogadi’) or for other social functions affecting the family. other sources included salaries from working household members (23.7%) and for all elderly citizens aged 65 and above, a monthly allowance from the government’s old age pension scheme (10.5%). in contrast, most households (72%) in bobonong study site earned their main income through temporary employment or ‘piece jobs’. these are traditionally low paying jobs like herding livestock, weeding of crop fields and joining the government’s labour intensive public works programme, among others. sales from agriculture and allowances from the old age pension scheme were the main source of income for some households (8% each), followed closely by salaries at 6%. unemployment rate in the area was recorded at 19.1% in 2003 (mfdp, 2007). gender and education levels most households were headed by members aged 41 years and older, with 72 and 89% in bobonong and kgalagadi north sub-districts respectively, very few of whom had gone beyond primary education. the level of formal education of the head of a household has some significance, as higher literacy is more likely to encourage better planning and decision making. there were 56% of heads of households with some formal education in bobonong, while kgalagadi had 76.3% of such respondents. there was a disparity in gender-where 64% of the households were female-headed in bobonong while 23.7% were headed by females in kgalagadi north. special attention has been paid to rural female-headed households over the years (cownie and blake, 1982; molutsi, 1992) as they tend to be prone to shocks because of high poverty levels (jefferis and kelly, 1999), lack of access to land, low literacy levels (eriksen et al., 2005), lack of draught power, and high dependency ratios (fako and molamu, 1995). in bobonong, of all household heads with no formal education, 68.2% were femaleheaded and their main source of income was the low paying temporary employment opportunities (69.4%), characteristics which jacques (1995) argues, indicates high likelihood of vulnerability to drought. ownership of livestock livestock rearing has long been regarded as batswana’s (citizenry of botswana) way of life (edwards et al., 1989), despite its declining contribution to the country’s gross domestic product over the years (bidpa, 2001). this is further supported by the study findings where 94% of all households surveyed owned some livestock (cattle, goats, sheep, horses, donkeys, pigs and poultry). cattle are especially important as they affect the culture, politics, economy and the ecology of rural botswana and its inhabitants (keijsper, 1993). looking at the livestock ownership dynamics in bobonong, the most common were poultry (68%), goats (64%), donkeys (60%) followed by cattle (50%) and lastly sheep (16%). donkeys are an important mode of transport for rural farmers (e.g. transporting water and harvests to markets), but their true worth are as draught power during the ploughing and planting seasons. a point to note is the relatively lower percentage of households owning cattle in the area. a possible explanation for this anomaly is the persistence of the economically important foot and mouth disease (fmd) in the area, which results in the mass killing of all infected cattle by the government. or the combination of recurrent droughts and fmd means that farmers spend most of their time trying to accumulate enough numbers for subsistence and possible sales. so cattle ownership in the area may be low not necessarily because cattle are less valued, but because of the associated risk. by contrast, kgalagadi north sub-district has no fmd threat and had more households owning cattle (84.2%), goats (81.6%), poultry (60.5%), donkeys (52.6), horses (39.5%) and sheep (15.9%). horses are used by herdsmen mainly when looking after other livestock, especially suited to navigate kgalagadi’s extensive and predator-filled terrain. livestock ownership versus age and gender also drew special attention. of all the households without cattle in both sub-districts, 74.2% were female-headed and were thus termed ‘poor’. there was also skewed ownership of livestock with regard to the age of the household head. for example, the youth (≤ 40 years) owned only 16 and 12.5% of all cattle in bobonong and kgalagadi north sub-districts respectively, further fuelling the perception that they are not keen on agricultural-related activities (car, 2005). factors limiting households from coping with drought though households may have strategies in place to avert the negative consequences of droughts; there are some factors that hamper the full success of their efforts (figure 4). in the study area of bobonong, the top-ranked constraints were persistence of droughts (20%), lack of diversified sources of income (20%), limited alternative options (18%) and wildlife menace (14%). recurrent droughts are seen as constraint primarily because they disrupt the agro-pastoral communities’ efforts to subsist on the land. there is no regular pattern of drought episodes in botswana, but an average periodicity of approximately 16 to 20 years has been observed (mfdp, 1997). hitchcock (1979) argues that variability in rainfall has increased since 1954. this increased frequency of droughts in the study areas could have overwhelmed some of the traditional coping and adaptation strategies and rendering them ineffective. this has necessitated adoption of more responsive coping strategies among the agro-pastoralists, which may not always be available. for example, while in the past, the ‘mafisa’ system enabled beneficiaries to ‘lease’ livestock and water points from wealthy members of their community (bidpa, 1997); nowadays an animal would be adversely affected by recurrent droughts and hence produce less milk or be too weak to provide draught power or even die. thus this strategy would not only be risky to the one ‘leasing’ out their resource (like livestock), but also to the one in whose custody the resource is temporarily transferred. instead, the wealthy would rather hold on to their investment, while the poor would rather harvest firewood for sale or enrol in the government’s labour intensive public works programme where there is a guarantee of monthly payment which is a highly responsive strategy vis-à-vis ‘mafisa’ with a delayed time lag before benefits are realized. the over-reliance on one source for income (rain-fed agriculture), coupled with limited alternatives also make it difficult for households to cushion droughts once the agricultural sector experiences shortfalls. the area of bobonong is also occasionally affected by elephants (loxodonta africana), especially during extended dry seasons and droughts. the animals are attracted to the water in hand-dug wells meant for livestock and also destroy farmers’ crops. considering the recurrent droughts, the risky subsistence nature of farming, lack of l a c k o f o p ti o n s p o o r s o il ty p e n o i rr ig a ti o n p o o r h e a lt h o ld a g e l a n d t e n u re s to c k d is e a s e s d iv e rs if ie d e n te rp ri s e l a c k i n p u t n o n figure 4. constraints limiting households from coping and adapting to drought. employment opportunities, and outbreaks of foot and mouth disease in the bobonong sub-district, perhaps the communities ought to look at the elephants and other wildlife as a blessing in disguise. the community-based natural resource management (cbnrm) policy (1997) encourages communities in wildlife management areas to form trusts and develop land use and management plans with the assistance of the department of wildlife and national parks. the cbnrm concept satisfies both economic interests of the local residents (e.g. through tourism, hunting quotas and cultural villages) and the country’s resource conservation objectives, thereby promoting sustainable development. in the other sub-district of kgalagadi north, lack of water or its poor quality (high salinity) were cited and ranked as the main constraints by farmers (23%), followed closely by lack of diversified sources of income (21%). like in bobonong study area, persistence of drought was seen as a constraint (14%). the other important constraint was the land tenure system (9%) which hampered farmers’ efforts to cope with droughts. low, erratic rainfall and associated excessive evaporation rates make water a limiting factor for agropastoral communities of kgalagadi north. hand-dug wells at the edges of the numerous pans around the district are the main source of livestock drinking water. during drought years, because of depletion of palatable forage in the vicinity of the water bodies, animals have to traverse greater distances between distant grazing areas and water points. thus borehole drilling in the communal areas offers a lifeline for farmer groups (syndicates) where underground water is not too saline. according to the farmers, if they had to choose one of the lesser evils between lack of feed (natural pastures) for their livestock and lack of water, they would opt for the former. this demonstrates the invaluable need for water in their agricultural activities. the persistence of droughts in this area could have also contributed to some households not cultivating crops at all, as the arable sector is more sensitive to moisture deficits than livestock. according to van der jagt (1995), a possibility of crop failure in the area ranges between 1 in 5 and 1 in 4 years. seasonal movements of livestock across the rangeland to exploit the high spatial variability of rainfall as well as heterogeneity of forage are the norm in semi arid and arid environments. but the current land tenure system in botswana curtails such mobility. this gives rise to another constraint in efforts to cope with drought. in the case of kgalagadi north, the communal area in which the cattleposts are located is adjacent to wildlife management areas and the kgalagadi transfrontier park (state land), some privately-owned ranches (leased under tribal land) and the permanent human settlements/villages (tribal land). because of the different land uses bordering them, agro-pastoralists can only move their livestock within the communal area itself. the physiology of cattle also dictates where to move to, and thus mobility is often restricted to natural water bodies (pans). a proposal is offered by nyangito (2005), who suggests that pastoral mobility can be enhanced by employing secondary land tenure rights to access privately-owned grazing resources during critical periods like droughts. this remains largely unexplored in the case of botswana. the preceding constraints may act solely or in combination to hamper the communities’ efforts in coping adequately with droughts, and thus increase their vulnerability. if one adds to these challenges the low, highly variable rainfall regime and climate-dependent livelihoods in both study areas, then there can only be one outcome, the perfect drought. conclusions rural agro-pastoral communities of the kalahari are exposed to recurrent droughts at increased frequencies. the low soil fertility status, coupled with the low and highly variable rainfall regime make for a challenging environment for the farmers to operate under. apart from this marginal agricultural potential of the land, there are other social and economic factors hampering farmers’ efforts to make ends meet. it is thus necessary to understand and appreciate these often subtle and complex challenges for effective future intervention strategies to reduce vulnerability among agro-pastoral communities and ensure sustainable rural development. acknowledgements the department of agricultural research provided full logistical and technical support for field data collection. the same institute also analysed soil samples. the department of extension services assisted with identifying farmers for the survey. rainfall data were sourced from the department of meteorological services. financial support for this project was provided by the regional universities forum for capacity building in agriculture (ruforum). sincere gratitude is especially extended to the communities of bobonong and kgalagadi north sub-districts who despite the odds, continue to prosper. references adger wn (1996). approaches to vulnerability to climate change. global environmental change working papers. centre for social and economic research on the global environment, norwich. apru (animal production and range research unit) (1980). beef production and range management in botswana. government printers, gaborone, botswana. apru (animal production and range research unit) (1976). an integrated programme of beef cattle and range research in botswana (1970-1976). ministry of agriculture, gaborone, botswana. bhalotra ypr (1985). rainfall maps of botswana. dept. of met. services, gaborone, botswana. bidpa (botswana institute of development and policy analysis) (2001). the final report of 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determining organic carbon and nitrogen in soils. j. agric. sci., 25: 598-609. weare pr, yalala a (1971). provisional vegetation map of botswana. botswana notes rec., 3: 131-152. in ternationa l scholars journa ls african journal of environmental economics and management issn 2375-0707 vol. 10 (4), pp. 001-005, april, 2022. available online at www.internationalscholarsjournals.org © international scholars journals author(s) retain the copyright of this article. review resuspension of sediment as a method for managing shallow eutrophic lagoons mauro lenzi lagoon ecology and aquaculture laboratory (lealab), oplrl company, italy. e-mail: lealab1@gmail.com. tel: +0564860288. fax: +0564867572. accepted 21 august, 2021 the article sets out to demonstrate that resuspension of sediment could be used to counteract the consequences of eutrophication and to manage degraded coastal lagoons subject to frequent periodic dystrophic processes. this is done by a general review of the literature on resuspension of sediment, focusing on its effects in shallow eutrophic lagoons and the results of specific research recently conducted by the author. key words: lagoon, eutrophication, sediment resuspension, lagoon biogeochemistry, lagoon management. introduction bottom disturbance causing resuspension of sediment in the water column is usually considered a negative phenomenon. resuspension of normally steady soft sediment, for example by gales, can have a considerable impact on the water body by raising organic particles and dissolved organic matter towards the surface (hopkinson, 1985), activating bacterial oxidative mineralization (fanning et al., 1982) and increasing the remineralisation rate (wainright, 1987; wainright, 1990). resuspension may also activate transport of nutrients in sediment interstitial water and adsorbed on sediment particles. using a simulation model, wainright and hopkinson (1997) established that resuspension causes release of nutrients, an increase in carbonates and increased oxygen consumption in the water column. however, there are contradictory results and different opinions about the effects of resuspension of sediment on the water column. in fact, much depends on the nature of the sediments, the height of the water column, the quality of organic matter present and the environmental conditions under which disturbance occurs (tengeberg et al., 2003; arnosti and holmer, 2003). resuspension of sediment may lead to oxidation of iron to ferric oxides, which adsorb orthophosphates, removing them from the water column (golterman, 1995; 2001). thus the impact of resuspension may differ considerably from one place to another, in relation, for example, to the amount of iron available in sediments. according to søndergaard et al. (1992), in lake aresø (denmark), where sediments are low in iron, resuspension is the main factor determining an increase in orthophosphates. on the other hand, in a laboratory study, sloth et al. (1996) found that resuspension multiplied dissolved oxygen (do) consumption by ten with respect to control, but caused modest changes in nutrient flow. in laboratory experiments on deep water sediments, koschinsky et al. (2001) did not find increases in dissolved organic carbon, heavy metals, nutrients or microbiological activity as a result of adsorption by resuspended sediment matter. tengeberg et al. (2003) found that natural resuspension in a swedish coastal area in winter reduced carbonates and phosphates in the water column and increased do, silicates, nitrites and nitrates, while ammonia remained unchanged. according to these authors, the effects of resuspension can vary in relation to bottom conditions and season. according to blackburn (1997), a resus-pension event leads to a sudden increase in nitrogen, by mixing interstitial water into the water column, but the same amount would be released in any case by diffusion gradient over a longer period. tengberg et al. (2003) sustain that more field research is needed to clarify the effects of resuspension in different seasons of the year and its long-term effects. repeated disturbance and resuspension of sediment the effects of occasional resuspension are one case, the effects of which may vary in relation to sediment conditions, accumulation of organic matter, the quality of the latter and water column conditions. the effects of disturbance repeated with a relatively high frequency may be quite different. in laboratory studies, stahlberg et al. (2006) showed that frequent resuspension of sediment increased the mineralization rate with respect to undisturbed sediment by a factor between 2 and 5. in an experiment conduced in a limited area of a shallow lagoon (orbetello lagoon, italy), lenzi et al. (2005) found that repeated passages of boats that resuspended soft surface sediment increased the oxidative status of sediments (increase in redox potential eh), reducing the organic content, without any significant increase in nutrients or oxygen consumption in the water column. lenzi et al. (2010) found substantially the same results in two large areas (20 ha each) of another coastal lagoon (lake burano, italy) when surface sediment was repeatedly disturbed with a specially fitted boat. the trend of dissolved sulphides in this experiment suggested that disturbance interrupted sulphate reduction processes. a possible hypothesis may be that an area subject to frequent turbulence affecting surface sediment, for example every 24-48 h as stated by stahlberg et al. (2006), may undergo an increase in the mineralization rate, as sustained by these authors, without showing any significant effect on the water column, in line with lenzi et al. (2005; 2010). in sediments with oxidative status, orthophosphates bind to ferric oxides-hydroxides (golterman, 1995; 2001), carbonates and clays (dodge et al., 1984; de jonge and villerius, 1989), becoming increasingly rare in interstitial waters and released less into the water column, in other words, unavailable to algae. as far as nitrogen compounds are concerned, oxidation accelerates nitrification and leads to pre-dominance of nitrates over the reduced forms, nitrite and ammonium (revsbech et al., 1980). an increase in nitrate concentrations produces an increase in denitrification (herbert and nedwell, 1990), which occurs in anoxic microhabitats (in an oxidative milieu) (fenchel, 1992), with the result that part of the sediment nitrogen is lost as n2 or n2o and the eutrophy of the system declines (novicki et al., 1997). thus, when a sedimentary substrate undergoes frequent disturbance, oxidation occurs, labile organic matter is reduced, orthophosphates are not released and there is partial loss of nitrogen. eutrophication problem in shallow water lagoons in marine sediments, including those of lagoons and other transition environments, more than 50% of organic matter is degraded by bacterial sulphate-reduction processes (sulphate respiration) (jørgensen, 1983). many coastal lagoons and estuaries become eutrophic and produce excessive macroalgal biomass in warm months (morand and briand, 1996). these conditions lead to major build up of organic matter in sediments, increasing sulphate-reduction. breakdown of organic matter by this process produces the acidifying gases co2 and h2s. dissolved sulphides are toxic and may have considerable impact (hijs et al., 2000). this may act on bicarbonate equilibria of interstitial water and water in contact with sediment, producing a white precipitate of caco3 (deelman, 1975). the sediment becomes more acidic and more reduced (very low eh values), leading to build-up of reduced and reducing components. low redox potential and ph lead to production of ammonium (marty et al., 1990) and nitrite by ammonification of organic matter, and this too has a toxic effect on fauna (torresberistain et al., 2006), besides stimulating production of nitrophilic algal species. natural baffering natural buffering hinders this trend. production of free sulphide (h2s, hs , s 2) by sulphate-reduction is countered by ferrous and ferric ions: h2s is oxidized by ferric iron (h2s↑+2fe +++ = s↓ + 2fe ++ + 2h + ) and blocked as sulphide by ferrous iron, as ferrous sulphide (h2s↑+fe ++ = fes↓ + 2h + ) and then as pyrite (fes↓ + s↓ = fes2↓) (berner, 1984; luther, 1991; richard and luther, 1997; theberge and luther, 1997; rozan et al., 2002). the pool of iron available in sediment may be sufficient to block dystrophic episodes, but if the quantity of organic matter exceeds availability (h2s/fe>1), then h2s enters the water column (giordani et al., 1996), with reducing action (removal of oxygen and anoxia) and toxic effects. reduction of iron and its blockade by h2s releases orthophosphates previously bound to ferric oxides-hydroxides (gunnars and blomqvist, 1997; golterman, 2001; rozan et al., 2002). thus orthophosphates are mobilised into the water column, where they are available to algae. macroalgal and microalgal blooms in coastal lagoons with little water exchange, the anoxia established in sediments due to high nutrient load and accumulation of organic matter leads to increasing degradation and continual stress for populations in the warm season, resulting in selection of opportunistic species and in a sudden and drastic change in the phytobenthos (valiela et al., 1997). this is immediately evident for rooted plants, development of which is curbed by bacterial and chemical conditions in the sediment, by epiphytes development, by phytoplankton that excludes light and by floating macroalgae that can suffocate figure 1. scheme of biogeochemical events induced by resuspension of sediment in eutrophic lagoon environments. seagrass meadows (den, 1994; raffaelli et al., 1998). high eutrophication favours the change from seagrass to seaweed, and if conditions worsen, to oppor-tunistic microphytes, which have high turnover (duarte, 1995). lenzi et al. (2003) observed a macroalgal distribution gradient with phosphorophilic macroalgae near a manmade nutrient source and nitrophilic macro-algae at some distance from it. finally, anoxia and the bacteria associated with the sulphur cycle may mobilise mineral contaminants, such as mercury in cinnabar as methylmercury (ch3hg + ) (wood and wang, 1983). these mechanisms are not yet well known and call for further research. conclusions: a possible tool for lagoon management in the framework of such eutrophic environments with little water exchange, frequent disturbance of sediment counters persistence of dystrophic conditions. by virtue of the geo-chemico-physical effects that it produces, disturbance leads to a new selection of bacterial, plant and animal populations, in the opposite direction to the selection produced by eutrophy and dystrophy: oxidative mineralising strains of bacteria increase, fall-out of resuspended matter increases sediment bacterial activity in the vicinity of the disturbed area (logan and kirchman, 1991), infauna biodiversity increases (widdicombe and austen, 2001), macroalgae suffer phosphorus limitation (lenzi et al., 2003) and recolonization of the substrate by phanerogams that capture nutrients directly through their roots is promoted. a simplified scheme of the process is shown in figure 1. this result was evident during operations carried out to combat severe eutrophication of orbetello lagoon, which in the first years consisted largely of macroalgal removal by harvesting boats. though only 3-6% of the estimated maximum macroalgal standing crop was harvested, a radical change in vegetation quality and quantity was obtained in only two years. chlorophyta decreased sharply, rhodophyta took their place but developed less, and phanerogams which had been completely eliminated by the environmental crisis, returned (lenzi et al., 2003). the subsequent experiment with a special boat equipped to raise soft sediment in lake burano showed a drastic reduction in macroalgal populations and an increase in phanerogams (with many seedlings establishing directly from seed) in disturbed areas (total, 44 ha) but not in undisturbed areas (total, 40 ha) (lenzi et al., 2010). much has still to be done to establish whether the answer to our initial question is positive, however the results so far are encouraging for eutrophic shallow-water environments. under these conditions, it has little sense wondering whether sediment disturbance can somehow damage the ecosystem, since it is already severely threatened by frequent dystrophic crises. fish of commercial interest are often severely impoverished, many microenvironments and typical species are lost and biodiversity is generally reduced in these areas. of course it is prudent to check sediments for contaminants, as some are best not diffused in the water column (kim et al., 2006; kalnejais et al., 2007). shallow bottoms make disturbance easy using boats of a suitable size or fitted with motors that mix air and water and direct a jet towards the bottom, suspending the top 3 to 4 cm of sediment. it is more complex, but not impossible, to disturb the bottoms of lagoons and estuaries deeper than 2 m. for example, a trawl for catching flatfish and pectinids, known as “rapido” (franceschini et al., 2000), could be modified by removing the net and teeth that engage the bottom and adjusting the skids to avoid direct contact with the bottom. dragged by a boat, this device could be used to disturb and resuspend superficial sediment in relatively deep water. it would be worth analysing whether this management criterion gives better results than more conventional measures, which are mainly of an engineering nature, such as creation of underwater channels where sediment collects, cement banks, pumping stations to admit sea water and flow accelerators, and environmental emergency works, such as harvesting and disposal of algae, and so forth. many of these operations have heavy 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resuspension and their contribution to the planktonic food web. mar. ecol. prog. ser., 62: 271-281. wainright sc, hopkinson jcs (1997). effects of sediment resuspension on organic matter processing in coastal environments: a simulation model. j. marine syst., 11: 353-368. widdicombe s, austen mc (2001). the interaction between physical disturbance and organic enrichment: an important element in structuring benthic communities. limnol. oceanogr., 46(7): 1720– 1733. wood jm, wang hk (1983). microbial resistance to heavy metals. environ. sci. technol., 17: 82-90. in ternationa l scholars journa ls african journal of environmental economics and management issn 2375-0707 vol. 8 (4), pp. 001-011, april, 2020. available online at www.internationalscholarsjournals.org © international scholars journals author(s) retain the copyright of this article. full length research paper assessment of heavy metal pollution in soils along major roadside areas in botswana k. b. mmolawa1*, a. s. likuku2 and g. k. gaboutloeloe1 1 department of agricultural engineering and land planning, botswana college of agriculture, private bag 0027, gaborone, botswana. 2 department of basic sciences, botswana college of agriculture, private bag 0027, gaborone, botswana. accepted 21 january, 2020 assessment of heavy metal pollutants: al, co, cu, fe, pb, mn, ni and zn was conducted along major roadside soils of botswana, lying between latitudes 18°s to 27°s and longitudes 20°e to 29°e using enrichment factor ratios (ef), contamination factor (cf), pollution load index (pli) and geoaccumulation index (igeo) methods. the studied sites were demarcated into five zones referred to as fn (francistown-nata), nm (nata-maun), mg (maun-ghanzi), gk (ghanzikang) and ts (tshabong-sekoma). all the four pollution assessment methods revealed that zones fn, nm and mg are pollution impacted as compared to gk and ts zones. results of multivariate analysis suggest mixed origins of pollution sources including human activities, vehicular emissions and lithogenic occurrences. al, cu, fe, mn, zn and co is of mixed origins of pollutants, with fe and mn being predominantly lithogenic, and vehicular emissions characterised by pb and ni. the findings in this study will serve to create awareness of vehicular heavy metal pollution to botswana policy makers in the mitigation of vehicular pollution, as it is barely monitored. key words: heavy metal contamination, roadside soils, enrichment factors, contamination factor, pollution load index, geoaccumulation index, cluster analysis, factor analysis. introduction pollution of the natural environment by heavy metals is a universal problem because these metals are indestructible and most of them have toxic effects on living organisms, when permissible concentration levels are exceeded. heavy metals frequently reported in literature with regards to potential hazards and occurrences in contaminated soils are cd, cr, pb, zn, fe and cu (akoto et al., 2008; alloway, 1995). vehicle exhausts, as well as several industrial activities emit these heavy metals so that soils, plants and even residents along roads with heavy traffic loads are subjected to increasing levels of contamination with heavy metals (ghrefat and yusuf, 2006). road construction has been the main activity for development of industrial units. this has led to the loss of forest cover and subsequent loss of soil fertility. roadside *corresponding author. e-mail: kmmolawa@temo.bca.bw. tel: +267 3650195. fax: 267 398753. soils often show a high degree of contamination that can be attributed to motor vehicles. various researchers have found that the concentrations of the metals pb, cu, zn, cd and ni decrease rapidly within 10 to 50 m from the roadsides (joshi et al., 2010; pagotto et al., 2001). according to panek and zawodny (1993), pollution of roadside soils and plants by combustion of leaded petrol products is localized and usually limited to a belt of several metres wide on either side of the road, and that for similar topography and vegetation, the level of pollution decreases with the distance from the road. due to their cation exchange capacity, complexing organic substances, oxides and carbonates have high retention capacity for heavy metals. hence contamination levels increase continuously as long as the nearby sources remain active. nevertheless, some heavy metals attached to the soil particles can be removed from the soil surfaces and get translocated elsewhere by the action of water and wind (harrison et al., 1981; ndiokwere, 1984; ghrefat and yusuf, 2006). mmolawa et al. (2010), demonstrated that heavy metal (a) (b) nm fn background 10 km mg sample 0.5 km 10 km gk sampled sites along roads direction of ts road travel figure 1. (a) map of botswana locating the sampled sites (indicated by dots along major roads). sites were zoned as follows; francistownnata (fn); nata-maun (nm); maun-ghanzi (mg); ghanzi-kang (gk) and tshabong-sekoma (ts), and (b) schematic drawing of field procedure showing the sampling sites (empty circles) relative to the background sampled site (closed circle). contamination by al, co, cu, fe, mn, ni, pb and zn was variable along major botswana roadside soils with pb being extremely enriched in the soils, mainly due to vehicular emissions. however, the authors in this study used world background reference values to determine enrichment factors due to unavailability of local background. due to spatial variability in lithology and mineralogy, world reference has been known to be erractic when used to determine enrichment factors (abrahim and parker, 2008). the present study assessed heavy metal pollution in soils using locally determined background values for metal concentrations, employing in-depth heavy metal analysis using four different approaches. the objectives of the present work were to: (1) assess heavy metal contamination by al, co, cu, fe, mn, ni, pb and zn using background soils obtained some 0.5-1 km away from sampling sites; (2) assess roadside soil contamination using four approaches, namely; (a) enrichment factor (ef), (b) contamination factor (cf), (c) pollution load index (pli), and (d) geoaccumulation index (igeo), and (3) classify heavy metals by their similarities and establish their probable sources using both cluster and factor analysis, respectively. materials and methods study area the study was conducted along major roadside areas of botswana lying in latitudes 18 to 27°s and longitudes 20 to 29°e. the country has a semi-arid climate, with highly variable rainfall, both spatially and temporally. on annual averages, rainfall ranges from 250 mm in the extreme southwest and 650 mm in the extreme north (batisani and yarnal, 2010). the south-eastern part and the north is dominated by grassland and savannah trees whereas the ghanzi, kgalagadi and the west of southern and kweneng districts have sparse trees and grasses. the soils can be generally categorised according to the predominant physiographic units of the sandveld and hardveld. the hardveld is characterised by soils which have been weathered and alluvial deposits. on the other hand, the sandveld area is mostly covered by the kgalagadi sands (batisani and yarnal, 2010). . site description and sampling techniques soils were randomly collected along major roadsides (figure 1a), avoiding areas with obvious signs of disturbance such as animal burrowing and landfills. the distances between sampling sites were chosen to be about 50 or 100 km, depending on proximity of major settlements. four samples were collected at each location as follows: one sample at about 10 km before the 50th (or 100th) km stretch, the second one at the site of concern and another one about 10 km after the site of concern. the fourth (background or control) sample was collected at least 500 m away from the direction of sampling locations (figure 1b). all soils were sampled at the surface (0 to 10 cm in depth) using hand driven stainless steel augers. exact locations for all sampled sites were determined using a global positioning system and entered into a geographical information system for data processing. sample preparation and analysis collected soil samples were air-dried to constant weight and then sieved through a 500 µm stainless steel mesh wire. samples of 0.5 g were digested in 20 ml freshly prepared aqua regia (1:3 hno3: hcl) on a hot plate for 3 h, then evaporated and analysed for metal concentration. standard reference material was prepared using stock solution from saarchm and merch and was used to have a check on the accuracy of the results. the total concentrations of al, co, cu, fe, pb, mn, ni and zn in filtrate were then determined using a flame atomic absorption spectrometer (varian spectraa 220 fs) at wavelengths, λ: al = 309.3 nm; co = 240.7 nm; cu = 324.8 nm; fe = 372.0 nm; pb = 217.0 nm; mn = 279.5; ni = 232.0 nm and zn = 213.9 nm, using air acetylene flame. assessment of metal contamination enrichment factor (ef) assessment of metal and level of contamination in soils require preanthropogenic knowledge of metal concentrations to act as pristine values. a number of different enrichment calculation methods and different reference material have been reported (ogusola et al., 1994; gaiero et al., 1997; sutherland et al., 2000; kamau, 2002; valdés et al., 2005; ghrefat and yusuf, 2006; abrahim and parker, 2008; akoto et al., 2008; dragović et al., 2008; charkravarty and patgiri, 2009; harikumar and jisha, 2010; sekabira, 2010; olubunmi and olorunsola, 2010). in this manuscript, the degree of anthropogenic pollution was established by adapting enrichment factor ratios (ef) used by sutherland et al. (2000), as follows: ef  c m sample (1) median cm background  2  mad cm background where, cm sample is the concentration of a given metal along the roadside. median cm background is median concentration of an element in the background soil sample and mad cm background is the median absolute deviation from median, defined as: each site was evaluated for the extent of metal pollution by employing the method based on the pollution load index (pli) developed by thomilson et al. (1980), as follows: 1 pli  cf1  cf2  cf3  k cfn  (4) n where n is the number of metals studied (eight in this study) and cf is the contamination factor calculated as described in equation 3. the pli provides simple but comparative means for assessing a site quality, where a value of pli < 1 denote perfection; pli = 1 present that only baseline levels of pollutants are present and pli > 1 would indicate deterioration of site quality (thomilson et al., 1980). this type of measure has however been defined by some authors in several ways, for example, as the numerical sum of eight specific contamination factors (hakanson, 1980), whereas, abrahim (2005) assessed the site quality as the arithmetic mean of the analysed pollutants. in this study, the authors found it appropriate to express the pli as the geometric mean of the studied pollutants since this method tends to reduce the outliers, which might bias the reported results. geoaccumulation index (igeo) enrichment of metal concentration above baseline concentrations was calculated using the method proposed by muller (1969), termed the geoaccumulation index (igeo). this method assesses the metal pollution in terms of seven (0 to 6) enrichment classes ranging from background concentration to very heavily polluted, as follows: cm sample (5) i geo  log2 1.5  cm background the factor 1.5 is introduced in this equation to minimise the effect of mad  median  x1 − median j x j   (2) possible variations in the background values, cm background, which may be attributed to lithogenic variations in soils. the seven proposed descriptive classes for igeo values are given in table 1 (muller, 1969). statistical analysis contamination factor (cf) the level of contamination of soil by metal is expressed in terms of a contamination factor (cf) calculated as: in order to study the characteristics of roadside soils, the concentrations of heavy metals content in surface soils were subjected to correlation analysis, principal component factor analysis (pca) and hierarchical cluster analysis (ca) by spss pasw statistics 17 to determine association as well as the differences in the concentration between different zones. results and discussion cf  cm sample (3) heavy metal concentrations in soils c m background  where the contamination factor cf < 1 refers to low contamination; the mean heavy metal concentrations (in µg/g) along roadside soils ranged from (12.80 to 34.46) al; (0.01 to 1 ≤ cf < 3 means moderate contamination; 3 ≤ cf ≤ 6 indicates 0.02) co; (0.02 to 0.08) cu; (25.36 to 87) fe; (0.04 to considerable contamination and cf > 6 indicates very high 0.51) mn; (0.37 to 0.48) ni; (0.04 to 0.21) and (0.05 to contamination. ef < 2: deficiently to minimal enrichment 2 ≤ ef < 5: moderate enrichment 5 ≤ ef < 20: significant enrichment 20 ≤ ef < 40: very high enrichment ef ≥ 40: extremely high enrichment this method is less affected by extremes in the tail often encountered with geochemical data, because the data in the tails have less influence on the calculation of the median than they do on the mean (chester et al., 1985; gaiero et al., 1997). enrichment factor categories for equation 1 are outlined as follows: table 1. the igeo classes with respect to soil quality. igeovalue igeoclass designation of soil quality > 5 6 extremely contaminated 4 5 5 strongly to extremely contaminated 3 4 4 strongly contaminated 2 3 3 moderately to strongly contaminated 1 2 2 moderately contaminated 0 1 1 uncontaminated to moderately contaminated 0 0 uncontaminated figure 2. enrichment factors for heavy metals along roadside soils for each sampled zone. 0.14) zn. since this study is the first of its kind for botswana major roadside soils, there is no local information in literature available for comparison. data reported here were therefore used to examine the extent of contamination by al, co, cu, fe, pb, mn, ni and zn using comparable pristine samples obtained at least 0.5 km from the roadside sampled sites. concentrations of individual heavy metal elements and their background data are given in the appendix. enrichment factor enrichment factors of various metals in the roadside soils in sampled zones are presented in figure 2. according to figure 2, ef ratios suggest that all metals are deficiently to minimally enriched. these results are contrary to those previously reported by mmolawa et al. (2010). in their preliminary study, the authors reported moderate (co, cu, fe and ni) to extreme (pb) enrichment in most roadside soils studied here. the dissimilarities may however, be ascribed to the different approaches used in the enrichment factor calculation methods. the previous study employed a normalised enrichment factor approach for metal concentrations using world uncontaminated background soils values, and iron as a metal of normalization, an approach which is less reliable since it ignores the fact that some geologic materials may have naturally high element concentrations and that the world reference values could be higher or lower compared to local conditions. contamination factor (cf) contamination factors of various metals in the roadside soils in sampled zones are presented in table 2. using the contamination factor categories previously described, zones fn and mg suffered moderate contamination by all metals except co and zn, respectively. on the other hand, zones gk and ts table 2. contamination factors for heavy metals along roadside soils for each sampled zone. al co cu fe mn ni pb zn fn 1.46 0.86 1.30 1.05 1.95 1.18 1.21 1.01 nm 0.93 0.78 1.01 0.69 1.36 1.02 2.14 0.50 mg 1.10 1.07 1.56 1.52 2.60 1.16 1.51 0.93 gk 1.30 0.39 0.44 0.39 0.22 0.91 0.37 0.38 ts 0.59 0.91 0.47 0.88 0.30 1.01 0.57 0.52 figure 3. pollution load index, pli for the eight metals studied at the sites. displayed low contamination by all metals except for al and ni, respectively, which showed moderate contamination. zone nm displayed moderate contamination by cu, mn, ni and pb, and low contamination by al, co, fe and zn. pollution load index (pli) to effectively compare whether the five stations suffer contamination or not, the pollution load index, pli, described in equation 4, was used. the pli is aimed at providing a measure of the degree of overall contamination at a sampling site. figure 3 shows results of the pli for the eight metals studied at these zones. based on results presented in figure 3, the overall degree of contamination by the 8 metals is of the order mg > fn > nm > ts > gk. mg and fn show strong signs of pollution or deterioration of site quality, whereas nm is almost at baseline level. sites gk and ts suggest perfection (or no overall pollution). relatively high pli values at mg, fn and, to some degree, nm suggest input from anthropogenic sources attributed to increased human activities and/or vehicular emissions. these sites are along a major highway connecting a number of townships and villages having higher populations and establishments. furthermore, fn zone is along the highway which is frequently used by commercial trucks for transportation of goods to and from zambia and other countries into central africa. geoaccumulation index (igeo) the calculated geoaccumulation (igeo) values are presented in figure 4. it is evident from figure 4 that the uncontaminated to moderately contaminated igeo value of ‘0 to 1’ is observed at zone mg by cu, fe, mn and pb, at zone nm by pb and at zone fn by mn. as revealed from the four pollution assessment methods; igeo, pli, cf and to a less degree, ef, roadside soils of zones fn, nm and mg are pollution impacted, as compared to gk and ts zones. statistical tests were figure 4. geoaccumulation indices of heavy metals along the roadside soils. table 3. the spearman’s rank correlation coefficient, ρ, between concentrations of metals in fn, nm, mg, gk and ts zones. al co cu fe mn ni pb zn al 1.000 co 0.013 1.000 cu 0.324* 0.291 1.000 fe 0.110 0.268 0.342* 1.000 mn 0.506** 0.361* 0.811** 0.307 1.000 ni 0.338* 0.091 0.484** 0.240 0.556** 1.000 pb 0.056 0.253 0.649** 0.385* 0.602** 0.170 1.000 zn 0.350* 0.323* 0.434** 0.335* 0.593** 0.421** 0.293 1.000 * correlation is significant at the 0.05 level (2-tail)..** correlation is significant at the 0.01 level (2-tail). then performed to establish the inter-metal relationships, and classify metals. statistical analysis analysis of variance was employed to determine whether groups of variables have the same mean. sites showed no significant effect on variation between group means of the heavy metals at different zones except for copper (p < 0.001), manganese (p < 0.003) and zinc (p < 0.05). this suggests that there is some degree of input of these (cu, mn and zn) metals between sites. inter-elemental association was also evaluated by spearman’s rank correlation coefficient, ρ and the results are presented in table 3. table 3 indicates that some elemental pairs, for example al/mn (r = 0.51, df = 28, p < 0.001), cu/mn (r = 0.81, df = 28, p < 0.0001), and cu/pb (r = 0.65, df = 28, p < 0.0001) etc, have strong correlations with each other. on the other hand, pairs such as al/cu (r = 0.22, df = 28, p < 0.05), al/ni (r = 0.34, df = 28, p < 0.05), and al/zn (r = 0.35, df = 28, p < 0.05) are moderately significant, whereas the rest of elemental pairs show no significant correlation with each other. strong correlations signify that each paired elements have common contamination sources. physico-chemical properties and metal associations were however not performed in the present study, to help in ascertaining these results. agglomeration schedule of cluster analysis (ca) was performed on data using nearest neighbour linkage and euclidean distance as a measure of proximity between rescaled distance clusters combined figure 5. dendrogram derived from hierarchical analysed soils. samples. results of ca are shown in figure 5. the hierarchical cluster analysis using nearest neighbour method produced two clusters, between which the variables were significantly (p < 0.05) different. the first cluster contained co, cu, zn, pb, mn, ni and al. these elements were classified as anthropogenic in origin, leaving mn and al as originating from mixed (anthropogenic and lithogenic) sources. the second cluster discriminated the lithogenic fe. similar studies by al-momani (2009) found pb to be strongly associated with vehicular emissions and zn to be associated with various industries and metal smelting processes. according to fergusson and kim (1991), co, mn, al, cu, ni and cu are associated with traffic related sources such as corrosion of metallic part, concrete materials, reentrained dust from roads and tear and wear of tyres and engine parts principal component analysis (pca) was performed to establish possible factors that contribute towards the metal concentrations and source apportionment. all data set was subjected to factor analysis (fa). the number of significant principal components (pc) was selected on the basis of varimax orthogonal rotation with kaiser normalisation with eigenvalue greater than 1. the rotated component matrix is given in table 4, and illustrated in figure 6. only the first two components comprising of 60.87% of cluster analysis of heavy metals content in table 4. factor analysis (after varimax rotation) showing contribution of statistically dominant variables measured in this study. variable pc-1 pc-2 al 0.742 -0.039 co 0.562 0.185 cu 0.783 -0.032 fe 0.701 0.128 mn 0.872 -0.007 ni 0.456 0.614 pb 0.146 -0.917 zn 0.784 0.155 eigenvalue 3.574 1.295 % of total variance 44.680 16.188 cumulative (%) 44.680 60.867 the total cumulative variances were retained. the first principal component, pc-1 explains that 44.68% of the total variance is highly loaded by al, cu, fe, mn, zn and moderately loaded by co. this factor is a source of mixed sources including human activity and vehicular emissions, which is evident from the fact that the soils were excavated alongside major highways connecting a number of townships and villages having higher pc-1 pc-2 figure 6. loading plots of pca analysis of heavy metals concentration for roadside soils of botswana. populations and establishments. close association of these metals is supported by their significant correlation (table 3) and cluster 1 from ca results. the association of mn and fe could also be due to their common occurrence in the basic rock, since the concentrations of these elements were lower than that the background values (igeo < 0) except for fn and mg zones whose igeo class category for mn was ‘1’ and again, igeo class = 1 for al just for zone mg. the second component pc-2 accounts for 16.19% of the total variance and contains ni and pb. pc-2 is strongly loaded by pb indicating that its source is from vehicular emissions. it has been proven that leaded gasoline contributes to pb concentrations in soils. the moderate loading of ni in pc-2, shared in between, to a lesser extent, pc-1 suggests both vehicular and industrial origins. conclusions anthropogenically impacted and background soils on major roadsides were assessed using enrichment factors, contamination factors, pollution load index and geoaccumulation index for al, co, cu, fe, mn, ni, pb and zn. enrichment factor ratios showed that all elements were deficiently to minimally enriched. the contamination factor showed that generally there is low and moderate contamination of the heavy metals across the zones fn, nm, mg, gk, and ts. the geoaccumulation index showed that zones fn, nm, and mg are uncontaminated to moderately contami nated, whereas zones gk and ts are uncontaminated. the measure of the degree of overall contamination (pli) at a site indicated strong signs of pollution deterioration by the eight measured metals at zones mg and fn, no overall contamination at ts and gk and a baseline level contamination category for nm. cluster analysis revealed two groups of metals having close similarities: firstly co, cu, zn, pb, mn, ni and al, classified as anthropogenic and secondly lithogenic fe. factor analysis generated two sources of pollutants; firstly mixed origin of sources including human activities, vehicular emissions and lithogenic occurrences characterised by al, cu, fe, mn, zn and co, and secondly vehicular emissions characterised by pb and ni. acknowledgements the authors are gratefully 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vargas g, sifeddine a, orttlieb l guiñez m (2005). distribution and enrichment evaluation of heavy metals in mejillones bay (23°s), northern chile: geochemical and statistical approach. mar. pollut. bull. 50: 1558–1568. appendix 1. concentrations of heavy metals in roadside and background soils (µg/g). zone fn al co cu fe mn ni pb zn fn1a 54.70 0.01 0.08 109.98 0.43 0.51 0.13 0.10 fn 38.32 0.01 0.08 39.75 0.37 0.46 0.10 0.10 fn1b 33.92 0.04 0.15 256.04 0.41 0.55 0.13 0.12 fn2a 38.70 0.01 0.12 14.82 0.69 0.46 0.13 0.14 fn 68.39 0.05 0.04 12.19 0.71 0.62 0.06 0.29 fn2b 30.75 0.01 0.04 13.33 0.35 0.50 0.08 0.09 fn3a 24.52 0.02 0.02 78.07 0.28 0.42 0.03 0.29 fn 14.63 0.00 0.02 46.67 0.11 0.40 0.34 0.07 fn3b 6.17 0.03 0.01 39.00 0.07 0.38 0.09 0.06 mean 34.46 0.02 0.06 67.76 0.38 0.48 0.12 0.14 s.d 19.04 0.02 0.05 77.66 0.22 0.08 0.09 0.09 fbb 47.99 0.02 0.11 280.52 0.97 0.50 0.01 0.34 zone nm nm1a 14.20 0.03 0.04 40.36 0.18 0.42 0.07 0.10 nm 40.76 0.01 0.05 51.78 0.33 0.31 1.30 0.06 nm1b 16.03 0.02 0.04 48.32 0.27 0.39 0.14 0.05 nm2a 14.82 0.01 0.04 32.35 0.22 0.42 0.06 0.11 nm 17.96 0.02 0.04 40.16 0.31 0.38 0.06 0.06 nm2b 50.38 0.01 0.06 90.80 0.42 0.47 0.07 0.07 nm3a 22.53 0.03 0.06 49.18 0.31 0.43 0.10 0.07 nm 8.34 0.02 0.06 22.59 0.20 0.47 0.07 0.05 nm3b 11.84 0.00 0.06 23.12 0.16 0.42 0.06 0.05 mean 21.87 0.02 0.05 44.30 0.26 0.41 0.21 0.07 s.d 14.19 0.01 0.01 20.47 0.08 0.05 0.41 0.02 nmb 23.58 0.01 0.05 47.17 0.20 0.41 0.19 0.14 zone mg mg1a 15.09 0.03 0.05 34.56 0.22 0.52 0.07 0.06 mg 14.06 0.01 0.07 52.98 0.17 0.21 0.49 0.10 mg1b 0.00 0.02 0.06 19.92 0.14 0.41 0.07 0.04 mg2a 15.78 0.01 0.06 79.16 0.19 0.45 0.08 0.06 mg 74.50 0.06 0.12 274.94 0.93 0.51 0.08 0.32 mg2b 50.80 0.02 0.09 43.06 1.46 0.45 0.12 0.27 mg3a 15.63 0.03 0.08 76.62 0.42 0.45 0.23 0.08 mg 25.03 0.00 0.07 115.24 0.29 0.73 0.09 0.07 mg3b 21.53 0.04 0.09 184.16 0.75 0.51 0.13 0.16 mean 25.60 0.02 0.07 92.78 0.48 0.46 0.16 0.13 sd 21.45 0.02 0.02 79.80 0.44 0.13 0.13 0.10 mgb 63.18 0.06 0.11 488.76 0.75 0.51 0.10 0.13 zone gk gk1a 24.34 0.01 0.02 32.62 0.03 0.38 0.04 0.11 gk 31.33 0.02 0.02 30.74 0.02 0.29 0.04 0.05 gk1b 32.06 0.00 0.03 31.89 0.10 0.30 0.03 0.03 gk2a 30.23 0.00 0.01 19.97 0.08 0.42 0.04 0.04 gk 32.06 0.01 0.02 21.08 0.01 0.38 0.03 0.04 gk2b 33.42 0.00 0.02 15.84 0.01 0.44 0.04 0.05 mean 35.23 0.02 0.03 91.56 0.14 0.39 0.05 0.06 s.d 12.67 0.02 0.03 175.27 0.27 0.08 0.02 0.04 gkb 6.32 0.02 0.02 27.67 0.07 0.40 0.31 0.15 appendix 1. contd. zone ts ts1a 20.43 0.06 0.03 92.48 0.07 0.41 0.06 0.09 ts 15.39 0.00 0.02 63.03 0.07 0.48 0.04 0.07 ts1b 15.17 0.00 0.02 58.51 0.05 0.52 0.05 0.06 ts2a 9.53 0.03 0.02 56.32 0.05 0.33 0.08 0.05 ts 13.28 0.03 0.03 43.91 0.08 0.32 0.06 0.06 ts2b 9.45 0.00 0.02 27.23 0.03 0.39 0.05 0.10 mean 12.80 0.02 0.02 52.74 0.06 0.41 0.09 0.08 s.d 4.74 0.02 0.00 22.69 0.02 0.07 0.10 0.04 tsb 13.29 0.02 0.02 64.57 0.02 0.38 0.08 0.06 sd = standard deviation; fbb, nmb, mgb, gkb and tsb are background sites for the five zones, respectively. in ternationa l scholars journa ls african journal of environmental economics and management issn 2375-0707 vol. 8 (4), pp. 001-006, april, 2020. available online at www.internationalscholarsjournals.org © international scholars journals author(s) retain the copyright of this article. full length research paper purslane and natural vegetation as bioremediation tools to cope salinity in satsuma mandarin orchards cenk ceyhun kılıç1*, dilek anaç2, uygun aksoy3 and süer anaç4 1 bayindir vocational school, ege university, 35840 bayindir, izmir, turkey. 2 department of soil sciences, faculty of agriculture, ege university, 35100 bornova, izmir, turkey. 3 department of horticulture, faculty of agriculture, ege university, 35100 bornova, izmir, turkey. 4 department of farm structures and irrigation, faculty of agriculture, ege university, 35100 bornova, izmir, turkey. accepted 26 october, 2019 the objective of this study is to compare the na and cl removal capacity of natural vegetation (spontaneous flora) and cultivated purslane, as bioremediation techniques to overcome salinity in satsuma mandarin plantations. an experimental orchard was established on two different rootstocks, (poncirus trifoliata l.) raf. and troyer citrange (poncirus trifoliata × citrus sinensis)) and the orchard was irrigated at 2 different salinity levels (0.65 and 5 dsm -1 .the ground of the on rows of satsuma mandarin trees was kept either with its natural flora (vegetation) or with cultivated purslane. results are statistically examined with respect to the effects and interactions between the tested factors; rootstock, salinity and remediation tools. biomass yields of the tested alternatives (natural vegetation and purslane) and their na, cl, k and ca concentrations were measured. also na and cl concentrations of mandarin leaves were analyzed to examine the remediation effect. results showed that yield depressions of the natural vegetation plots were higher compared to purslane and showed a considerable difference according to the rootstock. sodium removal of purslane and natural vegetation was found to be similar. chloride uptake was lower in troyer citrange compared to p. trifoliata. purslane and/or natural vegetation can equally be recommended as na removing bioremediation crops. purslane can also be recommended as a promising cl remover suitable for orchards on p. trifoliata (l.) raf. rootstock. key words: bioremediation, natural vegetation, purslane, salinization, satsuma mandarin. introduction large areas of arable land are being abandoned each into the roots or the vascular system (walker and year due to misuse of soils like salinity (essa, 2002). douglass, 1983). the exclusion capacity can be bioremediation of the degraded crop land is an correlated with the sterol of roots (maas, 1993). environmentally and ecologically friendly practice. salinity calcium (ca) maintains the structural integrity and causes physiological and biological disorders like osmoselective permeability of root membranes (hanson, tic, toxic or ionic imbalances in the plant body (mengel 1984). the effect of salinity on nutrient composition of and kirby, 2004). plant tissues, especially the concentration of ca and k chloride (cl) and sodium (na) are for citrus orchards, the bioremediation of the land under risky ions *corresponding author. e-mail: cenk.kilic@ege.edu.tr. tel: +90 exclude cl or na from the scions (maas, 1993). 232 581 63 17. fax: + 90 232 581 71 75. in planthas been extensively investigated (munns, 2002; essa, growth under excess salinity conditions. sodium tole-2002). the authors reported that relatively high rance seems to involve the ability of xylem parenchyma concentrations of ca and k are essential for a successful cells to extract na from the xylem stream and sequester it growth in a saline environment. in the woody root and stem tissues (hepaksoy et al., one cost effective friendly method to cope with salinity 1999). chloride tolerance of plants can be heritable and is to grow salt tolerant species, varieties or to use be heritable and exclusion of cl seems to be controlled rootstocks tolerant/resistant to saline conditions. citrus in primarily by root membranes that either restricts cl entry general are very sensitive to salinity. in this regard, rootstockscion relations have been extensively studied (aksoy et al., 2000; hepaksoy et al., 1999). it is reported that citrus rootstocks considerably vary in their ability to salinity threat could be done by using salt removing crops either as cover crops or as intercrops between or on the tree rows or by leaving the ground with its natural flora (vegetation) to enhance salt uptake. kumamoto et al. (1990) and grieve and suarez (1997) rated purslane as a very good salt removing crop according to mass and hoffman (1997). however, not much information is available for the salt removing capacity of natural vegetation under mediterranean conditions. nazik (2007), bilen (2008) and unal (2009) specified the yearly differences in the dominant natural vegetation species and reported that spontaneous vegetation can change yearly due to climatic conditions, main crop and fertilization. bilen (2008) highlighted that under mediterranean climate conditions, capsella bursa-pastoris is found as the dominant flora when long term annual average precipitation was not reached. however, when the rainfall is not restricted, lamium purpureum is found to dominate. the main objective of this study was to compare na and cl removal capacity of natural vegetation (spontaneous flora) and the cultivated purslane (underlying intercrop) as saline bioremediation techniques for satsuma mandarin trees budded onto two different root-stocks, poncirus trifoliata and troyer citrange. the study also aimed at determining the biomass yields, k and ca content of these two tested alternative underlying crops. in order to make a better evaluation, satsuma mandarin leaves were also analyzed for their na and cl contents with the purpose of measuring their tissue concentrations under different intercrop, rootstock and salinity conditions. materials and methods satsuma mandarin (citrus unshiu marc var. owari) is a well-known citrus species which ripens early in the season. an experimental plot of 0.45 ha located at ege university campus (izmir/turkey) was continuously irrigated with saline water for 13 years. the satsuma mandarins were budded on two different rootstocks, trifoliate orange (p. trifoliata (l.) raf. and troyer citrange (p. trifoliata × citrus sinensis). the plots were irrigated during the dry period (may to november) at 2 different salinity levels (0.65 ds m -1 (nonsaline treatment (fresh water) and 5.0 ds m -1 (saline treatment)) via double line source. fresh water from a deep well was supplied through one line and highly saline stock solution was distributed through the second line. the drippers were pressure regulated and their discharge rate was 2.3 l h -1 . irrigation was applied weekly based on previous day’s evaporation from uswb class a evaporation pan and the crop coefficient was used as 0.5 (doorenbos and kassam, 1979). two different bioremediation tools were tested in the citrus plot, as natural vegetation and purslane. experimental soils were sandy loam in texture with low calcium carbonate. organic matter, n, p and k were sufficient. the ec and ph of the saturation extracts of the salinized and non salinized plots were 2.0 to 7.8 ds/m and 5.65 to 7.70 at the beginning of the study. for one season, the ground of the on rows of satsuma mandarin trees was kept either with its natural flora (vegetation) or with purslane. in the purslane (p. oleracea l.) plot, the seeds were sown on a row 25 cm distant from the tree trunk, at a seeding intensity of 2 to 3 kgha -1 (0.2 to 0.3 g m 2 seed). purslane was harvested as recommended, 70 days after emergence before the formation of new seeds (vural et al., 2000). similarly, in the natural vegetation plot, wild species were allowed to grow spontaneously for about 120 days till the new seeds appear. the major species in the natural flora were identified by square frames (25 cm × 25 cm) which were randomly placed 5 times for each plot corresponding to a total sampled surface of 1 m 2 and their intensities (number per unit area m 2 ) were determined. in non salinized as well as salinized plots, number of urtica urens (stinging nettle) plants per unit area was the highest followed by malva sylvestris (mallow) and calendula arvensis (pot marigold). generally urtica emergence ranged from 41 to 91 per unit area. the experimental design was split-split plot with 3 replications, the main factor being the rootstock, second salinity of irrigation water and third the bioremediation tool. total fresh weight (biomass) of the harvested natural vegetation (g m -2 ) and the purslane (g plant -1 ) were weighed and their na, ca and k concentrations (% dry matter) were measured flamephotometrically and cl potentiometrically (kacar, 1972). after the irrigation, satsuma mandarin leaf samples were taken at the end of october to the beginning of november (chapman and pratt, 1961) and also analyzed for their na and cl contents according to the above stated standard methods (kacar, 1972). the paper presents the changes in biomass yield, na, k, ca and cl concentrations of the natural vegetation and purslane and na and cl concentrations of satsuma mandarin leaves. results are statistically examined with respect to the effects and interactions between the tested variables; rootstock, salination and remediation tools as natural vegetation and purslane. all the statistical analysis was done separately for purslane and natural vegetation for tested factors. the data obtained was subjected to analysis of variance (anova) and the mean differences were compared by lsd tests (açıkgöz et al., 2004). results biomass yield of purslane and natural vegetation the main effects of salination and rootstocks on the biomass yield of purslane and natural vegetation (flora) and their interactions were statistically significant. yield changed with respect to these factors (table 1). the relative yield depressions due to salination in purslane grown under satsuma mandarin trees were close to each other, being 51% in the case of p. trifoliata rootstock and 57% in troyer citrange compared to the yield obtained under non saline control conditions. therefore, the difference between the yield depressions of purslane can be accepted as slight. on the other hand, the relative yield depressions of the natural vegetation were 78.5 and 61.6% for p. trifoliata and troyer citrange rootstocks, respectively (table 1). sodium, cl, ca and k concentrations of purslane and natural vegetation sodium main effect of salination and rootstock on na concentration of purslane was found to be statistically significant. on the other hand, na concentration of the natural vege tation was affected only by salinity. the na concentrations table 1. biomass of purslane (g plant -1 ) and natural vegetation (g m -2 ) as a function of salinity and rootstocks. rootstocks salinity level fresh weight purslane (gplant -1 ) fresh weight natural flora (g m -2 ) p. trifoliata non-salinized parcel 26.73 a 2248 a salinized parcel 13.72 b 1766 b t. citrange non-salinized parcel 91.28 a 4860 a salinized parcel 52.36 b 2994 b lsd(0.05) (salt × rootstocks) 3.21** 85.11** **p<0.01. means in the same column followed by different letters are significantly different (p≤0.05). table 2. tissue na (mg kg -1 ) concentration of purslane and natural vegetation and as a function of salt. salinity level p. trifoliata t. citrange purslane natural flora purslane natural flora non-salinized parcel 957 b 522 b 957 a 609 b salinized parcel 1218 a 1479 a 2000 a 2050 a lsd(0.05) 31.01** 1185.59* **p<0.01, *p>0.05. means in the same column followed by different letters are significantly different (p≤0.05). table 3. tissue cl (%) concentration of purslane and natural vegetation as a function of salinity. salinity level p. trifoliata t. citrange purslane natural flora purslane natural flora non-salinized parcel 0.41 a 0.05 b 0.47 a 0.18 b salinized parcel 0.46 a 0.15 a 0.67 a 0.70 a lsd(0.05) 0.072* 0.46* *p<0.05. significantly different (p≤0.05). of the two tested salt removing crops purslane and natural vegetation also differed. the effect of salination on purslane grown under satsuma mandarin trees on p. trifoliata rootstock showed higher tissue na contents under saline conditions. similar condition existed in the case of na measurements of the natural vegetation. the effects of salination on purslane and natural vegetation grown under the other rootstock, troyer citrange were determined as significant at 5% level that is higher na concentrations were analyzed under saline conditions (table 2). when numerically evaluated, the natural flora grown under the satsuma trees on troyer citrange rootstock had higher na content. chloride main effects of salinity and rootstock on cl concentrations of purslane were found to be significant. in the case of natural vegetation, only the effect of rootstocks was statistically significant. the cl concentrations of the two remediation tools, purslane and natural vegetation, varied according to the treatments tested in the study. the effect of salinity showed higher cl concentrations in both purslane and natural vegetation under both rootstock plots. the difference was significantly (5%) higher in the case of natural vegetation (table 3). the effects of rootstocks put forth that the cl of purslane and natural vegetation grown under the trees on t. citrange rootstocks were respectively higher than those grown under the canopy of the trees on p. trifoliata rootstocks (table 3). potassium significant effects of salinity and rootstock were deter-mined on k concentrations of purslane and of natural vegetation. significant statistical interactions were found for the cases of p. trifoliata and t. citrange, salinity × remediation tools. under salinized conditions, k con-centrations of purslane and natural vegetation decreased. the level was almost 50% of the non-salinized conditions in case of purslane. table 4. tissue k (%) contents of purslane and natural vegetation as a function of salinity. salinity level p. trifoliata troyer citrange purslane natural flora purslane natural flora non-salinized parcel 1.30 a 1.20 a 1.47 a 1.24 a salinized parcel 0.64 b 0.84 b 0.77 b 0.88 b lsd(0.05) 0.118** 0.038** means in the same column followed by different letters are significantly different (p≤0.05). table 5. tissue ca (%) concentration of purslane and natural vegetation as a function of salinity levels. salinity levels p. trifoliata t. citrange purslane natural flora purslane natural flora non-salinized parcel 0.41 a 1.05 a 0.43 a 1.25 a salinized parcel 0.31 a 0.68 b 0.38 a 1.08 b lsd(0.05) 0.168* 0.140* *p<0.05. means in the same column followed by different letters are significantly different (p≤0.05). results related to non-salinized control conditions showed that k of the purslane under satsuma trees budded onto p. trifoliata was lower than the trees where troyer citrange was used as the rootstocks potassium concentrations of the natural vegetation grown under trees on both rootstocks were similar when there is no salinity problem (table 4). calcium calcium concentration of purslane was affected only by the increase in salinity levels. on the other hand, natural vegetation was significantly under the effect of both salination and rootstocks (table 5). the purslane and the natural vegetation under satsuma mandarin trees with p. trifoliata as the rootstocks had lower ca concentrations compared to that of those under troyer citrange. natural vegetation always had higher ca than that of purslane. leaf na and cl concentrations of mandarin trees the leaf cl concentrations of satsuma mandarin trees were found to be significantly higher in the salinized parcels on both of the rootstocks. in general, similar behavior was determined for the na contents of leaves which were also analyzed higher in the salinized trees. satsuma mandarin leaves had higher cl concentrations on p. trifoliata than that of troyer citrange. on troyer citrange higher leaf na levels were determined (table 6). discussion biomass production of purslane and natural vegetation plots under satsuma mandarin trees budded onto p. trifoliata and troyer citrange rootstocks were negatively affected by salinity. many researchers (maas, 1990; kılıç et al., 2008) state similar findings supporting the results of the present study. relative yield depressions due to salinity were found around 50% for purslane plots under these two rootstocks. on the other hand, yield depressions of the natural vegetation plots were higher and showed a considerable difference according to the rootstock. sodium generally does not damage the plants as does the cl (maas, 1993). according to the result of this study, na removal of purslane and natural vegetation was found similar even if the rootstocks differed. it is known that troyer citrange is a na includer that is, excess uptake with no damage (maas, 1990). in this case, higher na concentrations measured in the leaves of satsuma mandarin trees on troyer citrange rootstock confirm this finding. maas (1993) and kılıç et al. (2008) highlighted purslane as a strong cl removing crop. mengel and kirby (2004) state p. trifoliata as cl sensitive. the critical leaf cl concentration for satsuma mandarins budded on this specific rootstock is indicated to change between 0.20% (chapman, 1968) and 0.70% (cohen, 1976). our laboratory results related to high cl in the leaves of satsuma mandarin trees on p. trifoliata also fall within this range. on the other hand, findings in relation to troyer citrange showed some differences. the low cl contents measured in the leaves of troyer citrange can indicate its low uptake and exclusion more via roots. consequently, it can be claimed that the residual cl in table 6. sodium and chlorine concentrations of mandarin leaves as a function of salt and rootstocks. salinity levels cl (%) na (mg kg -1 ) p. trifoliata t. citrange p. trifoliata t. citrange non-salinized parcel 0.12 b 0.08 b 386 b 396 b salinized parcel 0.75 a 0.23 a 728 a 946 a lsd(0.05) 0.053** 5.971** **p<0.01, *p<0.05. means in the same column followed by different letters are significantly different (p≤0.05). the soil is highly taken up by the natural vegetation under tree canopy. this assumption is in accordance with cl results analyzed in the tissues of natural vegetation plots. under saline conditions, the effect of the underlying crop kept on the orchard ground can be significant in k losses due to the nutrient competence with the satsuma mandarin trees. the tested bioremediation tools, purslane and natural vegetation, responded more or less similarly in their k removal from the rhizosphere. the excess ca uptake from the growing environment of citrus trees can be effectively eliminated by a suitable rootstock. the underlying plant is important as well. in the present study, natural vegetation was found suitable in removing the highest amount of ca from the soil. kılıç (2005) reports a small difference between ca uptake of p. trifoliata and troyer citrange rootstocks, generally the latter having higher uptake rate. conclusion it is concluded that purslane and/or natural vegetation can equally be accepted as na removing bioremediation tool(s) for satsuma orchards established either on p. trifoliata or on troyer citrange rootstocks. it is also concluded that for cl remediation, purslane could be a suitable accumulator plant in orchards on p. trifoliata rootstock which is susceptible to cl due to its high uptake affinity. moreover, relatively lesser yield depressions in relation to cl hazard once again showed that purslane could be suggested for p.trifoliata. on the other hand, under mediterranean conditions, natural vegetation could be recommended for satsuma mandarin trees budded on to troyer citrange rootstock. troyer citrange rootstock excludes the excess cl via its roots. acknowledgement the research work was partially supported by the incodc programme of the commission of the european communities, contract number: erbic18ct 980266. references açıkgöz n, i̇lker 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economics and management issn: 2375-0707 vol. 4 (3), pp. 266-277, june, 2016. available online at www.internationalscholarsjournals.org © international scholars journals author(s) retain the copyright of this article. full length research paper valuation of environmental goods and services: the case of bale mountains national park, ethiopia 1yilma haroyu*, 2muktar bayeh and 2habte wolle 1 college of natural sciences, department of biology, arba minch university, arba minch, ethiopia. 2 college of natural sciences, department of wildlife management, arba minch university, arba minch, ethiopia. accepted 20 may, 2016 e valuation of non marketed environmental goods and services is a newly emerging research area particularly in ethiopia and other developing countries. the study was aimed to investigate willingness to pay for conservation of environmental services and local tourists' entrance fee of bale mountains national park as well as determinant factors affecting visiting interest of local community. the widely used and flexible technique of environmental valuation called contingent valuation method/cvm/ was used. respondents were given hypothetical project of conserving the park. hypothetical questions were prepared to elicit the maximum willingness to pay and willingness to accept to conserve the park. dinsho, goba and robe towns were purposefully selected from which 380 respondents were selected from stratified population using lottery method. logistic regression model was used to quantitatively analyze socio-economic factors of local people to visit the park. the research finding indicated that visitors mean entrance fee wtp is over 3 times the current entrance fee. maximum amount of willingness to pay for the proposed conservation project scenario varied from 0 to 1000birr (50$), whereas mean and mode were 35 $ and 10$. regression analysis showed sex, age, family size, and education level were significant determinants of visiting the park. in addition, district/nearness, education level, job, awareness of biodiversity importance and status, and income level of respondents positively affected an individual’s willingness to pay. generally, the survey was successful in eliciting willingness-to-pay for protecting the park and can potentially help policy makers as well as park managers to increase number of local tourists so as to increase revenue for conservation work. keywords: contingent valuation, conservation, environmental service, non-market values, tourism, willingness to pay. introduction nowadays, valuing environmental goods and service (g/s) are increasingly becoming a global concern. it is largely agreed that successful development activities depend on the efficient use of „natural capital‟ (world bank, 1998). however, the market for environmental services is substantial and growing throughout the world, driven in part by increasing environmental regulation and changing consumer preferences (unep, 2012; kunte et al., 1998), and in applying valuation techniques to the analysis of corresponding author. e-mail: yilmaharoyu@gmail.com the environmental g/s, both in developed and developing countries (bishop, 1999). however, to do so, several types of market failures can be defined (oecd, 1994). the most common type of market failure related to the environment is the failure to internalize, or take account of market values of g/s. before few years ago in production of goods and services, physical and human capital was recognized as the main factors of production. but nowadays, economists have recognized that natural capital is an important input in any type of production (tietenberg, 2006). an increasing number of economists nowadays, accept that natural capital is used for material and energy yilma et al. 267 inputs into production, acts as a "sink" for waste emissions from the economic process, and provides a variety of "ecological services" to sustain production, such as nutrient recycling, watershed protection and catchment functions, and climate regulation (tietenberg, 2006; mishra, 2013). environmental assets like other assets provide benefits that enhance economic performance (defra, 2007; pearce and turner, 1990; cesare, 2000; unep, 2012). public benefits derived from biodiversity and natural resource such as a national park in the form of environmental amenities and ecosystem services implies that the environmental goods and services contributes to public welfare, and loss of the resources or decline in their quality could result in a loss in welfare (tietenberg 2006). generally, literatures divide the value of environmental g/s into different categories. when considering why individuals place values on a natural resource, a typical approach in literature is to distinguish between those who use the resource (services) and those who do not (brauman etal, 2007). the values held by the former group are generally termed as use values, and may occur in many different ways. direct use values may derive from consumptive uses (e.g. fuel wood collection) and/or non-consumptive uses (e.g. hiking in the same forest), and may involve commercial (selling fuel wood or collecting visiting tolls) and/or non-commercial activities (home consumption of fuel wood or enjoyment of an open-access wilderness area) (cesare, 2000). only some of environmental goods and services that are very crucial for our existences have markets (cesare 2000) price (price tag) and these prices are most of the time very minimal. so, valuation of such goods and services is much more relevant (mcclelland, 1993) for sustainable development. some benefits of valuing environmental g/s are strengthening green growth (mcclelland, 1993; mishra, 2013), helps to better understanding of the value of the natural capital, rethink the territory in a more integrated and intelligent manner, and to conduct more realistic cost/benefit analysis which effectively promote the sustainability of the biodiversity in the territory, balancing the economic vision with the preservation/conservation of natural resources (santos, 2013). driven by the continuing desire of ethiopian government for green economic growth, the result of this research can potentially awake and ignite decision makers and policy makers at national level about monetary value of non marketable environmental g/s. in addition, an ability to place a monetary value on the services provided by the environmental g/s should increasingly be recognized by the broader research, policy and business communities. the welfare contribution or economic value of protected areas in developing countries, however, is scarce. similarly, both use values and non use values of these environmental services are not yet comprehensively understood in ethiopia. therefore, environmental management decision making process and policy makers, and conservation project implementers have no scientific background. according to bekabil and anemut (2000) very few studies analyzed local peoples willingness to pay (wtp) for conservation of national parks in ethiopia. there are no comprehensive studies done regarding the environmental services provided by bmnp. recreational value and even the entrance fee to enjoy the park is not based on the scientific study that really reflect the local tourists wtp. therefore, this study was aimed to examine the maximum amount of local tourists‟ willingness to pay to visit the park and the monetary value that people attach to the conservation of environmental services provided by bale mountain national park (bmnp) as well as the major determinant factors affecting the willingness of local community to visit the park and conservation scenario of the park. materials and methods description of the study area bmnp is situated in the oromia region encompassing 2,471km². the park is characterized for its afro alpine habitat, including alpine meadows; it contains the second largest moist tropical forest and the only cloud forest in ethiopia. with an altitudinal range from 4400 to 1500 meters, it harbors an enormous diversity of habitats. all of this has resulted in a unique ecosystem that contains such a high degree of endemism that it is the envy of national parks. it is estimated that if we were to lose the bale mountains more endemic mammals would go extinct than any similar sized area on our planet. two of our most recognized species, the ethiopian wolf and the mountain nyala, are safeguarded by the bale mountains national park, with more than 50% of the total populations of both these endangered species occurring within its boundaries (gmp, 2007). the park is home to several endemic mammal species, such as the mountain nyala, ethiopian wolf, giant mole rat and bale monkey. the forest area also provides a habitat for lion, african wild dog and giant forest hog. this park is safeguarding our ethiopian natural heritage. climatically, the area is characterized by a rainy season from march to october and a dry season from november to february. precipitation increases with altitude from 600mm to 1,000mm in the lower altitude areas to 1,000mm to 1,400mm in the high alpine areas of bmnp. mean monthly temperatures range from 19°c to 25.4°c. the harenna forest within bmnp and the adjacent mena angetu national forest priority area (nfpa) on the southern slope forms the second largest stand of moist tropical forest remaining in ethiopia covering about 1,800km². approximately, half of the park (877km²) lies 268 afr. j. environ. econ. manage. within this forest, which is home to high levels of biodiversity and endemism including many threatened species such as prunus africana. the forest contains wild coffee (coffee arabica) and is an important source of timber, ntfps, honey and dry season grazing. the entire forest is under considerable human induced pressure due to uncontrolled grazing and forest fire threatening the sustainability of the forest (abdurrahman, 2008). method of data collection socio-economic data survey to collect socio-economic characteristics of respondents, two main instruments, namely: questionnaire and focal group discussion were used. to improve the quality of the questionnaire, the researchers pre-tested and translated into „afaan oromo‟, the local language. accordingly, sex of household head, age, and district, and marriage status, religion of respondents, family size, educational status, occupation and income level of the respondents were the main socio-economic characteristics collected during data collection. in addition to these, a local peoples‟ perception of conservation activities, levels of knowledge about biodiversities exist in the bmnp, purpose of visiting the park, frequency and willingness of visiting the park (whether the respondent have taken any trips to the park for different reasons) and other relevant data were collected. focus group discussion three focal group discussions (fgds) were formed. each fgd had ten members. the first fgd was concerning hypothetical conservation of environmental goods and services project to be designed and implemented. this was done to elicit wtp and wta the bids and thereby to describe environmental g/s in monetary term. the second fgd was to make agreement on alternatives bids (ranges of birr (dollar) that the respondents were asked to vote as optimal entrance fee. the third fgd was to discuss an acceptable ways of funding the hypothetical project. we made a discussion on whether the hypothetical project could be funded by community only or both by government and the local community. the first group made up of higher officials of ethiopia wild life conservation authority and senior professionals of park management, wildlife conservation, tourism management and ethiopian biodiversity conservation institute. the second group and third group were made up of local expert office leaders as well as dinsho woreda administrative officers, and local farmers of five male and five female household heads. structure of contingent valuation design cvm survey design of loomis et al. (1996) was used, which comprise three elements: portraying the resource to be valued; describing particular financial mechanism (e.g., property taxes, utility bills, trust funds/donations, etc.) and eliciting the respondent‟s wtp in ethiopian birr (1 dollar=20.48 ethiopian birr during this study time). the nature of the goods and services and the changes valued (value of changes in terms of conservation of bmnp as a result of hypothetical project) were specified in details to respondent before directly asking how much respondents were willing to pay for a conservation program of bmnp.. for example, by asking, if the project cost household 100 birr (5$) each year, were he/she willing to pay the amount to implement the project. the dichotomous choice questionnaire mentioned above allowed to statistically trace out a demand relationship. to do so, the relationship was established between the probability of a “yes” response and the ethiopian birr (dollar) amount. prob (yes) = 1 – {1 + exp[ b0– b1x1+ b2x2+ b3x3+...bnxn]} –1 ……………………..1 where b: coefficients to be estimated using logit statistical techniques associated with the independent variables xi: ethiopian birr (us dollar) amount the household is asked to pay. then expected mean wtp value was calculated as: mean wtp = ( 1/b0) × ln (1 + exp[ b0– b1x1+b2x2+b3x3+...bnxn] )………..equation 2 sampling techniques and sample size determination three towns of bale zone namely dinsho, goba and robe were selected purposefully since residents of these towns have relatively good awareness of environmental g/s of bmnp. then respondents were selected randomly using lottery method. the population size of dinsho, goba and robe were 3609, 32025 and 44382 respectively. totally, population of the three selected districts was 80073 hhs. therefore, the total sample size was determined by the following formula; n = z 2 pqn 14611.4007……………………………………………………eq uation .1 e 2 (n-1)+z 2 pq where n=appropriate total sample size, n=total hh in the areas, p=5%/given/, e=marginal error=5%,q=.95,z=confident interval=1.96 n=1.96 2 *0.05*.95*80073 .05 2 (80073-1)+1.96 2 *.05*.95 =380hhs this sample size was allocated proportionally for the three towns: dinsho, goba and robe. method of data analysis both quantitative and qualitative methods of data analysis were employed to analyze the collected data. quantitatively, descriptive statistics such as mean, mode and rating techniques (likert scale) were used. in addition to this, logistic regression was used to analyze the socio-economic factors affecting local community‟s interest to visit the park and factors affecting the willingness to pay for the hypothetical conservation project. in logistic regression analysis dependent variable was dummy variable which took 1 if the respondents were visited the park so far and 0 otherwise. the different yilma et al. 269 socio-economic variables were used as explanatory variables. result and discussion socioeconomic characteristics this section presents the socio economic characteristics of the respondents. socio economic and demographic characteristics such as sex of household head, age, and district, and marriage status, religion of respondents, family size, educational status, occupation and income level of the respondents were analyzed and presented in table 1. the above table indicates most of the respondents were male (64.6%) and majority of them were married (57.1). only 9% of the respondents were illiterate and relatively high percentages (30.6%) of them have attended primary school. few respondents reported that they have attended others type of educational level (religious creeds, such as quran). 46.4% of the respondents occupied on petty trade and the significant percentage were government employer. only 10% of them were farmers. average entrance fee to visit the park visitors mean wtp to visit the park was over 3 times greater than the current entrance fee (20birr). the least and most typical entrance fee wtp was 20 birr (1$) whereas average entrance wtp was 60 birr (3$) (figure 2). similar study conducted on “visitors‟ willingness to pay for an entrance fee :a case study of marine parks in malaysia” showed that the willingness to pay (wtp) per person per visit to moderate the environmental impact of inland development is 5.95usd, which is lower than the wtp to reduce crowding, 7.89 usd (siti, 2009).however, in our case, the existing entrance fee set by the government is lower than the tourists willingness to pay simply to encourage the visiting frequency of both local and international tourists . thus, there is room of increasing entrance fee if the park managers desire to increase revenue by collecting money from local tourists in addition to what have been collected from international tourists. therefore, policy makers and/or park managers can set ethiopian birr ranging from 20-60 (1-3 usd) as entrance to visit the park particularly for local tourists. similarly, wide range of willingness to pay park entrance fee (50 to 150 dinars) for fruska gora mountain also found by aleksandra vujko and tamara gajic (2014). to sustainably conserve the biodiversity of the park, increasing the entrance fee is crucial especially to monitor and manage environmental goods and services. the respondents were asked to choose from different ranges of entrance fee and 70% of them voted to pay the range of 20-70 ethiopian birr (1-3.5$). figure 2 shows that, about 14% were willing to pay the highest bid (150 birr (7.5 $). therefore, the current entrance fee is not a limiting factor in determining number of entrance. the result of the study remarked that it is not appropriate to limit entrance fee to low amount. the low entrance fees fail to justify conservation of biodiversity or pursuance of a policy of cost recovery (mmopelwa et al., 2007). it is widely believed that is important to introduce an additional fee based on visitors interest (providing entrance fee option from minimum 20 (1$) to the mean of 60 birr (3$) and even as larger as they can offer). in some parts of the world, increasing park entrance fee was not significantly reduced visitor numbers, especially in the long-term since the demand for visiting the park is relatively inelastic (herath, 2000; shultz et al., 1998). this means, the amount of entrance fee should be open to the visitor above the set minimum fee to give chance for those visitors who are willing to pay more so as to make the national park a luxury or a snobbish good. purpose of visiting and reason why local people do not visit the park those respondents who responded they had visited the park were asked for what purpose they had visited the park so far and those who had not visited the park were also asked to indicate their reasons. accordingly, respondents reported that they visited the park for purpose of recreation, research and education. this is due to the fact that natural spaces can potentially provide an arena in which children and university students can learn outside of the classroom, and there is evidence to suggest that this is a more effective form of learning (sig, 2009). in another hand, people who have not visited the park so far reported that lack of visiting habit, unaffordable entrance fee, and the lack of information about benefit of bmnp / absence of advertisement, absence of attractive infrastructure and additional manmade recreational part of the park as the reasons for they had not visited the park. figure 3 indicates, only about 56% of the respondents visited the park and 43% of them had not visited though the park is near to them. table 2 presents the reasons of local people for visiting the park. about 70% of respondents answered that they visited the park for the sake of recreation. the study carried out to estimate the recreational benefit people gain from the loch garten site and the value (£0.57 million and £0.77 million per year) reported that an estimate of the benefit people enjoy from visiting the site, predominantly for recreation (value of biodiversity, 2006). however, only about two percent were visited for research work and about 16% for education purpose. the study finding showed, entrance fee was not a significant limiting factor that hinders respondents from 270 afr. j. environ. econ. manage. figure 1. location of the bale national park. table 1: socio-economic characteristics of the respondents. variables characteristics percentages sex male 64.6 female 35.4 marriage status single 40.8 married 57.1 divorced 2 religious muslim 40.1 christian 57.8 wakefata 1.4 family size 1-3 63.8 4-6 22.7 >6 13.5 level of education illiterate 9.5 primary 30.6 secondary school 27.2 university level 32 others /religious -.7 occupation petty trade 46.4 farming 10 government employer 43.6 visiting the park since only 7.2% of they responded reported they could not offer the current entrance fee to frequently visit the park. this result is quite different from studies conducted in australia that majority of the visitors (67 percent) said they pay 0 entrance fee to visit park. on the other hand, about 17.1 of the respondents mentioned that they have not visited the park because of all the described problems as reason for not visiting the park. yilma et al. 271 figure 2. willingness to pay for entrance fee wtp. local people attitude towards the importance of conserving bmnp under this sub section, we presented the value that the local people derive from the bale mountains national park. respondents reported that they derived both use and non use value of environmental goods and services from the park such as recreation, job opportunity, endemism, scenic value, education and research value. table 3 indicates likert scale of local people attitude regarding the benefits or importance of conserving bmnp. the presented result showed that conservation works and activities are very important (4 likert scale) for the purpose of recreation, to protect current endemism status, and scenic value whereas important (3 likert scale) for education and less important (2likert scale) for creating job opportunity, cultural value and research work. the research finding carried out by peter edwards & cyrus abivardi indicated that the recent powerful new argument for protecting biodiversity in the past 18 years since we need it for our survival(edwards &abivardi,19998). this realization has grown gradually as a result of the increasing scale of environmental problems we face, such as acidification. local people attitude towards harmful effect of human pressure in the absence conservation activities. table 4 indicates without the proposed project, natural and man-made factors and other human pressure have highly affect scenic beauty of the forest, tourism air quality, recreation and etc except fishing, risk of flood and water quality which respondents responded as these were not affected (2 likert scale) by the fire with and without the proposed conservation scenario. socio –economic factors affecting visiting interest of local people the socio-economic /characteristics /variables/ that determined the interest of local people to visit the park were analyzed using logistic regression (where independent variable was binary response,1 labeled as yes for who already visited the park and 0 labeled no for those who did not visited the park). logistic regression was used to identify socio economic factors affecting the wtp (oecd, 2002).the respondent‟s mean willingnessto-pay is influenced by a number of socio-economic and demographic factors. the result of logistic regression was put in table 5. as it is indicated in table 5, at 95% level of significance, four socioeconomic variables: sex(p=.00), family size(p=.005), level of education(.022) and occupation were variables significantly affected the interest of local people of visiting bale mountains national park. sex which is dummy variable (where 1 labeled if the respondents were male and 0 otherwise) affected the visiting interest of local people positively. this means that males were more likely to visit the park percent 0 5 10 15 20 25 30 35 m ax e nt ra nc e fe e 0 20 40 60 80 100 120 140 160 percent vs entrance fee (birr) percent vs mean percent vs mode 272 afr. j. environ. econ. manage. figure 3. percent of yes and no response of past experience of visiting the park. table 2. percentage of bmnp visiting and not visiting reasons. purpose of visiting the park % reasons for not visiting the park percent recreation 70.5 lack of visiting habit 54.1 research 2.7 unaffordable entrance fee 7.2 education 15.2 the details of bmnp not advertised enough 17.1 other 11.6 no additional manmade recreational part of the park 4.5 table 2. also presents lack of visiting habit was the most typical reason (54.1%) that prohibit local people from visiting the park. table 3. analysis of importance of conserving bmnp. recreation job opportunity endemism scenic value education culture value research value other median 4 2 4 4 3 3 4 4 mode 4 2 4 4 3 2 2 4 std. dev .81 .96 .61 .56 .53 .89 .72 .71 variance .66 .93 .37 .314 .28 .81 .53 .49 source: own survey, 2015/16. relative to females. on the other hand, family size affected the visiting interest of the local respondents negatively, as family size increases; local peoples were less likely to visit the park. level of education affected the no: 43.5 yes: 56.5 yilma et al. 273 table 4. effects of human pressure and fire on the park. s c e n ic b e a u ty t o u ri s m a ir q u a lit y s o il e ro s io n w a te r q u a lit y r is k o f fl o o d h e a lt h o f tr e e r e c re a ti o n f is h in g d iv e rs it y o f fa u n a d iv e rs it y o f fl o ra e n d e m ic s p e c ie s median 1 1 1 2 2 2 1 1 2 1 1 1 mode 1 1 1 2 2 2 1 1 2 1 1 1 std. deviation .84 .76 .81 .52 .51 .57 .71 2.7 .57 .66 .67 .67 variance .704 .57 .66 .27 .26 .33 .51 7.2 .32 .44 .44 .45 source: own survey, 2015/16. table 5: variable of determinants for visiting the park. variable coefficient s.e. p-value. sex 3.505 .740 .000 age .041 .046 .365 district .658 .407 .106 marriage .983 .738 .183 religion .652 .620 .293 family size -.489 .174 .005 education level .885 .345 .022 occupation 1.165 .538 .030 income level .475 .409 .0369 constant -7.655 2.176 .000 source: own survey, 2015/16. interest of visiting the park positively; which implies that, educated local people were more likely to visit the park relative to non educated individuals. determinants of willingness to pay for conservation of the park in addition to the investigated the local peoples‟ willingness to pay for entrance fee, respondents were given the bid and asked whether they were willing to accept the bid or not. accordingly, 77.6% of the respondents were willing to pay for the proposed conservation scenario while the remaining respondents were not because of two main possible reasons: the project itself did not convince them (32%) and they (68%) believed that they drive no benefit from the park (figure 4). study conducted in australia also indicated local peoples can have different reasons for the lack of willingness wtp for conservation (tisdell and wilson, 2003) the socio economic determinants of wtp for conservation of bmnp (table 6). the income of the local people has positive impact (p=0.023) on the respondent‟s willingness to contribute towards the realization of the targeted conservation scenario (table 6). this indicated that the households with more income were more likely to contribute for conservation of the park. similarly, occupation, familiarity with natural resources of the park, frequency of visiting and level of education were positively affected wtp of local people for conservation. households who were occupied on petty trade were more likely willing to contribute relative to farmers. the more peoples were familiar with natural resources and high frequency of visiting the park, the more they are willing to pay for conservation. the result indicated that if there are enough recreational facilities and necessary services provided at recreational areas, i.e. if tourists are satisfied with the recreational facilities and services, their willingness to pay increases (mamat et al, 2013). maximum willingness to pay the respondents were asked how much money in ethiopian birr they were willing to pay simply to understand how they value the environmental goods and service that are derived from the park. to elicit their willingness to pay, they were briefed how different factors aggravated the degradation of the bale mountains national park and conservation project (hypothetical) was designed to minimize the problems. after this, they were asked how much birr (dollar) they are willing to pay if the project cost is to be covered by local people, then a larger 274 afr. j. environ. econ. manage. figure 4. reasons for motivated local peoples wtp. table 6. determinants of willingness to pay for conservation of bmnp. explanatory variable β s.e. sig. sex -.386 .582 .507 age .009 .033 .789 district 1.117 .321 .000 marriage .851 .469 .070 religion .037 .434 .933 family size -.112 .124 .363 education level .825 .306 .032 job .155 .350 .007 visiting rate .551 .181 .02 familiarity on nr status 1.21 .509 .007 income level .699 .308 .023 source: own survey, 2015/16. percentage of visitors were willing to pay especially dinsho district (table 6). the study conducted in australia by clem tisdell and clevo wilson (2003) indicated that 64 percent of the respondents reported they would be willing to pay if the money is used for the benefit of the park, while only 26 percent said they were not willing to pay and the rest (10 percent) did not answer this question. this study result also shows that the amount they proposed for conservation highly varies from 0 to 1000 (figure 5) which indicates the degree of their awareness or consciousness such that respond ants would give priority to conservation of natural resources. using open ended query, though the maximum amount of willingness to pay for the conservation of bale mountain national park varies from 0-1000, mean and mode wtp for the proposed conservation project scenario were 697 and 200 birr (34.9 and 10 $) (figure 5). this implies that the respondents were willing to pay 697 on average annually for conservation purpose which indicates local communities give high value for the resource. since the maximum wtp found in this study and also studies conducted in other country, for instant, in malaysia reported that, such value can be used by the authority to determine the appropriate conservation fee (mohd parid mamat et al 2013). if the benefits could be demonstrated, then the „userpays‟ principle could become acceptable to most visitors and also at the same time obtain the political support of the public machado (2000). from the alternative bids presented to them, majority of respondents did choose p e rc e n t 0 20 40 60 80 100 yes no get no benefit not convinced a b yilma et al. 275 figure 5. maximum willingness to pay (wtp) for the proposed conservation project. figure 6. annual willingness to pay for the bmnp conservation scenario. annual wtp amount of 50-100 birr (2.5 – 5$) (figure 6). conclusion and recommendations the study tried to investigate the optimum entrance fee of visiting bale mountains national park, both socioeconomic factors and other the park related factors hindering local individuals to visit the park. the study revealed that the current entrance fee that visitors are paying is not significantly affecting the visiting interest of the local individuals. but lack of visiting habit and absence of manmade recreational sites which attract local individual tourists and lack advertisement and awareness creation regarding the recreational benefit of the park were the most significant factors affected the visiting interest of the local visitors. logistic regression analysis indicated that socio economic factors such as level of education, occupation (those occupied by petty m a x w t p f o r th e p ro p o s e d p ro je c t (b ir r) 0 2000 4000 6000 8000 10000 12000 robe goba dinsho yearly wtp for conservation (birr) 0 50-100 100-300 300-500 >1000 pe rc en t o f re sp on de nt s 0 10 20 30 40 50 276 afr. j. environ. econ. manage. trade were more likely to visit the park relative to farmers and other occupation), sex of households (male individuals were more likely to visit the park relative to female individuals) positively affected the interest and frequency of visiting the park. „family size‟, affected negatively the visiting interest of the local people. based on these findings, the researcher forwarded the followings are recommendation  government should give great attention for the development of recreational facilities  the park managers should exhaustively advertise the recreational benefit of the park to local individual in using local language, afaan oromoo  after setting the minimum entrance fee, visitors should be given opportunity of paying more (there should be mechanisms of making it legal with receipt)  educational office of bale zone should provide elder education for those who are illiterate to boost their participation in any affairs so as to increase their willingness to participate in conservation activities  conservation project aimed to minimize the degradation rate of bmnp whose cost is to be covered by local community can be designed in such as way that local people pay up to 697 birr (34.9$) after exhaustive and detail awareness creation regarding the importance of the project and the cost to be incurred to implement the project in very transparent way. acknowledgements this study was financially supported by the madda walabu university. bale mountain national park, goba, dinsho and sinana natural resources management experts has helped in providing secondary data and arranging group discussions. we also acknowledge the contribution of mr lema tiki, research coordinator of biodiversity and natural resources of mada walabu university who helped us in organizing and arranging seminars and comments from other researchers. lastly, we heart fully acknowledge local community of bale zone ,oromia region, for their cooperation in giving us reliable response to questions prepared to collect primary data references aleksandra vujko and tamara gajic (2014).persuasive communication and visitors willingness to pay park user fees. turizam volume 18, issue 1 1-10 (2014) bishop jt (1999). valuing forests: a review of methods and applications in developing countries. international institute for environment and development: london. brauman ka, daily gc, duarte tk and mooney ha (2007). the nature and value of ecosystem services: an overview highlighting hydrologic services. annu. rev. environ. resour. cesare dosi (2000). environmental values, valuation methods, and natural disaster damage assessment. he un eclac, italy. clem tisdell and clevo 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(1998), “opportunities and limitations of contingent valuation surveys to determine national park entrance fees: evidence from costa rica”, environment and development economics, 3: 131-149. unep, (2012). trade and environment briefings: environmental services. californi a, 94105, usa. value of biodiversity (2006); watched like never before (2006) rspb world bank (1998), “economic analysis and environmental assessment”. supplement of the environmental assessment sourcebook 23. washington d.c.: the world bank environment department. in ternationa l scholars journa ls african journal of environmental economics and management issn 2375-0707 vol. 7 (4), pp. 001-007, april, 2019. available online at www.internationalscholarsjournals.org © international scholars journals author(s) retain the copyright of this article. full length research paper effect of soil ph on sorption of salinomycin in clay and sandy soils r. jayashree*, shiv o. prasher, rajvinder kaur and ramanbhai m. patel department of bioresource engineering, macdonald campus of mcgill university, 21111, lakeshore road, sainte anne de bellevue, quebec, canadah9x 3v9, canada. accepted 20 september, 2018 salinomycin is polyether ionophore, commonly used in poultry industry for the prevention of coccidial infections and promotion of growth. a large amount of the administered antibiotic is excreted as parent compound, eventually reaching agricultural lands. this makes it imperative for researchers to understand the behavior of the compound in soil environment by conducting sorption-desorption studies. in this study, sorption of salinomycin was measured in four agricultural soils, a clay soil with low organic matter content (lom), a clay soil with high organic matter content (hom), a sandy soil with hom, and a loamy sandy (lom) soils, at three ph levels, namely 4, 7 and 9. desorption studies was carried out using the batch equilibration technique. it was observed that more than 98% salinomycin was strongly sorbed by all soils, irrespective of the soil organic matter content or soil ph. the sorption of salinomycin to the sandy soil marginally increased as the ph decreased, while the sorption to the two clay soils marginally increased as the ph increased. desorption of salinomycin with methanol over a 72 h period was < 0.2% of the amount added; however, it was > 70% with a phosphate buffer (ph 7). since the phosphate buffer would mimic, to some extent, the quality of water flowing through field soils containing various salts, it was concluded that salinomycin could pose significant threats to both shallow ground water and surface water bodies. key words: salinomycin, sorption, ph, desorption, environmental pollution, phosphate buffer. introduction antibiotics have been detected worldwide in soil, surface water, ground water, and sediment (kolpin et al., 2002; christian et al., 2003; kim and carlson, 2006). the persistence of antibiotics in terrestrial environments ranges from less than one day to weeks or even months, depending primarily on temperature and the chemical structure of the antibiotic (rabolle and splid, 2000). according to the rate of degradation and the sorptive properties, the parent substance or its metabolites may reach aquatic environments through surface runoff or leaching through the soil profile. key chemical properties, such as water solubility, soil ph, volatility, and sorption, influence antibiotic transport in soils. typical manure may also contain high levels of ammonia that would tend to increase the ph of soil solution, thus affecting the *corresponding author. email: jayashree.ramaswamy@gmail. com. sorption of certain compounds. salinomycin is a naturally occurring, monocarboxilic, polyether, and antibiotic, elaborated by a strain of streptomyces abbes (atcc – 21838). salinomycin is used for the prevention of coccidiosis in broiler chickens. the highest usage in usa is estimated to be 454 tons of salinomycin (active ingredient). salinomycin is also approved for use as a cattle feed additive (bio gro) in the range of 5 10 g ton -1 of complete feed. once administered, it can persist in organisms. a study conducted using radio labelled (c 14 ) reported that the salinomycin persists in food chain organisms, with moderately low biodegradability (eia, 1987). salinomycin is resistant to aerobic degradation. its relatively low aqueous solubility (3.4 mg ml -1 ) limits its availability for biological degradation, causing it to persist for longer periods in the environment (european food safety authority (efsa), 2004). the potential antibacterial effect of salinomycin in the environment would be against gram positive bacteria, at figure 1. structure of salinomycin. table 1. characteristics of salinomycin. salinomycin free acid molecular formula c42h70o11 molecular weight 750 melting point (c°) 112.5 – 113.5 pka 6.4 water solubility 3.4 mg ml -1 readily soluble in methanol stability unstable in acidic condition stable in alkali condition a pka = acid dissociation constant. levels of 0.39 µg ml -1 and above. it inhibits bacterial protein synthesis through the attachment to 9 transfer rna binding sites on the 30 s ribosomal unit (cater et al., 2000). it could change microbial populations in the environment. this, in turn, could undermine the ability of microbes to degrade other pollutants such as pesticides (boxall et al., 2003). this could also have deleterious effects on important chemical cycles, such as nitrification and denitrification (frestegard et al., 1997). salinomycin is unstable under acidic conditions and stable under alkaline conditions (efsa, 2004); therefore, its soil sorption is expected to be ph-dependent. currently, information about sorption of salinomycin to soil is not readily available. therefore, the objective of this study was to investigate the sorption behavior of salinomycin in four agricultural soils at three different ph levels (4, 7 and 9). materials and methods chemicals only analytical reagent grade or high purity chemicals were used in this study. sodium phosphate (mono and di basic), methanol, ammonium hydroxide and acetic acid were purchased from sigma. the salinomycin standard was obtained from sigma aldrich company. the structure of salinomycin is shown in figure 1 and selected properties are given in table 1. the stock solution of salinomycin was prepared by dissolving 10 mg salinomycin in 10 ml of methanol (meoh), and stored at 4°c. standard solutions were freshly prepared by diluting the stock solution with methanol in vials. soil characterization four agricultural soils with no previous history of exposure to salinomycin were collected from the macdonald campus farm of mcgill university in ste-anne de bellevue, quebec, canada. bearbrook soil is a dark-brown to grayish-brown clay having granular structure. generally free carbonate is absent in upper part of this soil. soils having high organic matter (hom-clay) and low organic matter (lom-clay) were collected from this soil series. the third soil was a dalhousie sandy soil with high organic matter (hom-sand). dalhousie soil was developed from lacustrine material, deposited as a thick covering. it is slightly alkaline. the fourth soil was chicot loamy sand having low organic matter (lomloamy sand). this soil is formed from thin alluvial material. all the soils were air-dried, passed through 2 mm sieve, and stored in plastic containers at room temperature for further analysis. physical and chemical properties of the soils were determined using standard methods: ph in a 2:5 soil:water slurry (trivedy and goel, 1986), organic carbon by wet digestion with k2cr2o7 and h2so4 (walkey and black, 1934), texture (by hydrometer method), and cation exchange capacity (cec) by atomic adsorption spectrometer. the various soil characteristics are listed in tables 2 and 3. ph adjustment the initial ph of the two clay (lom and hom), loamy sand and sandy soils were 6.7, 6.4, 6.9 and 6.7, respectively, (table 2). all four soils were equilibrated with 1 m concentrations of hcl and naoh. the ph was adjusted eight times over 20 days to stabilize at desired levels of 4 and 9. excess liquid from each soil sample was drained after ph adjustment, and soils were allowed to air dry for 48 h. soils were pulverized, rechecked for ph, and used for sorption studies. sorption the sorption experiments were performed with four different concentrations of salinomycin, 0.5, 5, 10 and 25 mg l -1 , in methanol. the uv-radiated sterile soils were used for sorption studies in order to minimize the effect of microbial growth and activity on the results. 20 ml of salinomycin solution was table 2. physio-chemical characteristics of soils used in this study. soil type oc (%) toc (%) om (%) ph soil texture sand (%) silt (%) clay (%) clay 4.31 5.7 9.88 6.7 30 20 50 clay 5.35 7.13 12.3 6.4 10 20 70 loamy sand 2.25 3 5.17 6.9 87.5 5.1 7.5 sand 3.9 5.2 8.96 6.7 92.5 2.5 5 a oc:organic carbon, toc:total organic carbon, om:organic matter. a m o u n t a d s o rb e d ( µ g /g ) 10.1 10.0 9.9 9.8 9.7 9.6 9.5 ph4 101 (% ) 100 99 ad so rb ed 98 97 a m o u n t 96 95 ph7 ph9 clay (hom) clay (lom) sand (hom) loamy sand(lom) figure 2. effect of ph on adsorption of salinomycin at 10 µg/g soil. added to the 1 g of sterile soil in a 100 ml conical flask to obtain final concentrations of 10, 100, 250, and 500 µg g -1 of soil. moreover, 20 ml of methanol was added to 1 g of soil for the blank, and 20 ml of each concentration of salinomycin solutions were kept in flasks, without soil, as controls. all samples were agitated for 24 h on a rotary shaker. after centrifugation at 3000 g for 30 min, supernatants were transferred to glass vials, filtered through 0.45 µm filters, and subsequently analyzed by hplc-cad (charged aerosol detector), to determine the amount of salinomycin remaining in solution. the sorbed salinomycin concentration was calculated using the following equation: vaq ci -c s  ms (1) where s is salinomycin sorbed to soil (µg g -1 ), vaq is the initial volume (l), ms is the soil mass (g), ci is the initial concentration (µg l -1 ) and c is the concentration remaining in the solution phase after equilibrium (µg l -1 ). as will be evidenced by the results presented later on, the four soils used in this study fully adsorbed the antibiotic. therefore, it became necessary to carry out further sorption tests by increasing antibiotic concentrations in order to make sure that the sorption capacity of soil is reached and there is antibiotic left in the solution phase, and, more importantly, to rule out any experimental errors or extremely fast chemical degradation (no microbial degradation was possible because all soils were sterilized before use). the highconcentration sorption tests were done on the sandy soil only. since this soil had hom, it was decided to purchase a lom-sand from a commercial outfit (reno department, pointe claire, quebec, canada) and to include it in the sorption/desorption study. the highest concentration used was 5,000 µg g -1 . an equal amount (20 ml) of methanol was added to the soil, and the flasks were agitated for 24 h, centrifuged, as previously described, and this procedure was repeated up to 72 h. analysis of salinomycin the filtered supernatants were analyzed for salinomycin using hplc cad (charged aerosol detector), equipped with c18 column. an elution gradient with methanol (80%), water (13%), ammonium hydroxide and acetic acid buffer (7%) (ph 5), and flow rate of 1 ml/min was followed. salinomycin concentration was determined using calibration curves. statistical analysis results obtained in this study were analyzed using two-way anova and multiple comparisons least significant difference (lsd). these tests were done using matlab, version 7.8. results and discussion the sorption of salinomycin in two clays, loamy sand and sandy soils at three different ph levels is presented in figures. 2, 3, 4 and 5 for 10, 100, 200, and 500 µg g -1 initial concentrations, respectively. figure 2 shows that, a m o u n t a d s o rb e d ( µ g /g ) 100.2 100.0 99.8 99.6 99.4 99.2 99.0 ph4 100.2 (% ) 100.0 ad so rb ed 99.8 99.6 99.4 a m o u n t 99.2 99.0 ph7 ph9 clay (hom) clay (lom) sand (hom) loamy sand(lom) figure 3. effect of ph on adsorption of salinomycin at 100 µg/g soil. a m o u n t a d s o rb e d ( µ g /g ) 200.2 200.0 199.8 199.6 199.4 199.2 199.0 ph4 ph7 100.1 (% ) 100.0 99.9 ad so rb ed 99.8 99.7 a m o u n t 99.6 99.5 ph9 clay (hom) clay (lom) sand (hom) loamy sand(lom) figure 4. effect of ph on adsorption of salinomycin at 200 µg/g soil. a m o u n t a d s o rb e d ( µ g /g ) 500.5 500.0 499.5 499.0 498.5 498.0 497.5 ph4 100.1 (% ) 100.0 ad so rb e d 99.9 99.8 a m o u n t 99.7 99.6 99.5 ph7 ph9 clay (hom) clay (lom) sand (hom) loamy sand(lom) figure 5. effect of ph on adsorption of salinomycin at 500 µg/g soil. table 3. chemical characteristics of soils used in this study (in cmol(+) kg -1 ). soil type ca mg k na mn fe cec clay (hom) 12.77 3.03 0.31 0.213 0.05 0.0166 16.4 clay (lom) 16.87 5.95 0.453 0.233 0.03 0.02 23.553 sand (hom) 3.323 1.02 0.12 0.06 0.01 0.02 4.656 loamy sand (lom) 2.426 0.07 0.053 0.133 0.01 0.02 2.686 a lom-low organic matter content; hom-high organic matter content, cec-cation exchange capacity. at 10 µg/g concentration, the sorption of salinomycin was higher (99.3~99.8%) in the sandy and loamy sandy soils, irrespective of organic matter content, at ph 4 and 7. it was slightly lower (95.5 97.0%) for the same at ph 9. multiple comparison lsd analysis showed salinomycin sorption in hom-clay to be significantly different (p < 0.05) from that in lom-clay, lom-loamy sand, and homsandy soils. in the sandy soil, at 100 µg g -1 concentration, the sorption of salinomycin was 100% at ph 4, followed by 99.7-99.8% at ph 7 and 99.4-99.5% at ph 9 (figure 3). at 200 and 500 µg g -1 levels also, the trend was similar, although, sorption was slightly higher (figures 4 and 5). this shows that salinomycin is strongly sorbed to the sandy soil; more than 95% of its initial amount is sorbed, irrespective of the organic matter content or ph level. one noticeable observation is that the amount sorbed to both sandy and loamy sandy soils was relatively small at ph 9 with 10 µg g -1 , as compared to the other ph levels. it was also observed that sorption was relatively higher in the soil with the higher organic matter content, as compared to the soil with the lower organic matter content. a significant difference (p < 0.05) was observed between hom-clay and lom-clay soils at 200 µg g -1 , and no significant difference was observed in the sandy and loamy sandy soils with low and high organic matter content. in the two clay soils, at 10 µg g -1 level, the sorption was slightly lower (97.8 98.3%) at ph 4, as compared to the other ph levels (99.9%) (figure 2). a similar trend was also observed for the other three concentrations (100, 200 and 500µg g -1 ), although 100% sorption was observed at ph 7 and 9 (figures 3, 4 and 5). the results show that salinomycin was also strongly sorbed to the clay soils, irrespective of the organic matter content. however, at ph 4, the sorption of salinomycin was higher in the hom-clay soil; the sorption was quite high at ph 7 and 9 for both levels of organic matter content. a clear contrast was observed between the sandy and clay soils at 10 µg g -1 concentrations. the sorption was lowest in the case of clay soils at ph 4, whereas it occurred at ph 9 in sandy soils. a significant difference (p < 0.05) was observed between ph 4, 7 and 9 in homand lom-clays and hom-sandy and lom-loamy sandy soils. sorption decreased with increasing ph in sandy and loamy sandy soils but not in the two clay soils. as the clay soils have high om content (9.88 12.3%), when ph increases, the humic molecules could have deprotonated, thereby increasing their negative charge. also, aluminum ions that are initially complexed to the organic matter could have started to hydrolyze and eventually precipitated as aluminium hydroxide. these processes would also contribute to the increase in negative charge. thus, clay soils have a higher ph-dependent cec. to some extent, the increasing exposure of negative charge on humic molecules with increasing ph may overcompensate the declining positive charge of salinomycin. theoretically, the maximum sorption of salinomycin on the variable charge of organic matter surfaces would occur at a ph value close to the pka value (acid dissociation constant). however, there may still be a substantial sorption, even at ph values which are several units higher than pka, due to selective sorption of charged molecules by the organic matter (berglof et al., 2002). higher sorption of antibiotics on clay-rich soils has also been reported previously (rabolle and splid, 2000; loke et al., 2002; kumar et al., 2004). thus, higher antibiotic adsorption on clay soils is mainly due to their greater exchange capacity because of the higher clay content and organic matter. loke et al. (2002) also reported that binding of salinomycin was influenced by ionic binding to divalent metal ions such as mg 2+ and ca 2+ . in clay loam soils, these ions were higher than in the sandy soils, thus this may have contributed to the higher sorption (table 3). organic matter was found to have a small effect on the sorption of salinomycin, and it was evident from all four soils (figures 2, 3, 4, and 5). all four soils used in this study were field soils and they had relatively high organic matter content (table 2). therefore, it was decided to investigate sorption behavior of salinomycin under low organic matter content conditions. to this end, construction sand was purchased from a local store with 0.3% organic matter content. again, the antibiotic sorption was found to be very high. it was decided to use even higher initial concentrations, that is, 5,000 and 10,000 µg g -1 ), but still most of the antibiotic was sorbed. this may be due to salinomycin’s greater ability to coordinate with inorganic cations in solution, resulting in increased hydrophobicity of salinomycin. this effectively neutralizes the carboxylic acid’s negative charge. also, salinomycin might interact with cations on soil exchange sites through cation bridging. to estimate the saturation point of salinomycin sorption in lom-sandy soil, a very a m o u n t d e s o rb e d ( u g /g ) 4000 3000 2000 1000 0 0 20 40 60 80 time (hours) methanol phosphate buffer figure 6. desorption of salinomycin in sandy soil. high initial concentration of 50,000 µg g -1 was used on the sandy soil since it was the least adsorbent amongst the four soils tested. it was found that nearly 35,000 µg g 1 was sorbed in 24 h. this indicates the sandy soil has very high sorption capacity for salinomycin. tolls (2001) reported that veterinary antibiotic sorption to soil cannot be predicted from compound kow (otanolwater partition coefficient) and soil organic carbon (oc) content. sithole et al. (2003) suggested that antibiotic interaction with soil organic matter occurs as a result of binding to divalent cations, ion exchange interactions, and hydrogen bonding between acidic groups in humic acids and polar groups on salinomycin. binding to divalent metal cations has also been suggested to explain salinomycin sorption in both marine and manure sediments. in addition, the carbonyl and either oxygen atoms can coordinate with metal ions, resulting in some degree of encapsulation (volmer and lock, 1998; paulus et al., 1998)). this coordination gives ionophores the unique ability to transport metal ions across cell membranes as either undissociated acids or neutral complexes and gives the molecule a largely hydrophobic exterior (shen and bradbelt, 2000; paulus et al., 1998; miao et al., 2003). salinomycin has a higher affinity for na + , k + , ca 2+ and mg 2+ with a strong preference for sodium (efsa, 2004). desorption of salinomycin was also performed in homsandy soil and the construction sand (lom) at higher concentration (5000 µg g -1 ) using methanol. the desorption results are shown in figure 6. while desorption was performed over a 72 h period, it was observed that only < 0.2% of the added amount desorbed from the soil (figure 6). this suggests that once salinomycin is sorbed on to these soils, its leaching to lower depths may not occur. however, since the desorption was being done with deionized water which may not be a good representative of rainwater making its way through the soil profile, it was decided to use a phosphate buffer for desorption. the percolating water will tend to dissolve several salts, commonly present in field soils, (especially phosphates) this condition is well mimicked by the phosphate buffer solution. shen and bradbelt (2000) have explained the mechanism of desorption using a phosphate buffer. the polar functionality of the antibiotic molecule, such as salinomycin, is oriented towards the cation at the centre, while the outer solvent-accessible portion of the molecule is largely hydrophobic (dobler, 1981; sobott et al., 1997). also, the carboxylic acid or ester groups, in addition to the tetrahydropyran or tetrahydrofuran groups in the backbone of ionophores like salinomycin can undergo anion exchange with soil to have a considerable anion exchange capacity, especially the high organic matter content soils. therefore, highly selective phosphate anions are capable of desorbing salinomycin. the results from our study showed that, out of 5,000 µg g -1 salinomycin, 3,450 µg g -1 had desorbed from the construction sand with the phosphate buffer after 24 h. when the desorption period was extended to 72 h, there was a minimal further increase in desorption a total of 3,525 µg g -1 was desorbed (figure 6). this showed that although, salinomycin is strongly sorbed to soil, it could also readily move into underground aquifers and water bodies under field conditions. conclusions sorption of salinomycin in clay and two sandy soils was very high (> 98%). it also tended to slightly increase with increasing soil organic matter and clay contents. the influence of ph on the sorption of salinomycin in various soils was quite different. sorption on the clay soil marginally increased as the ph increased, while sorption on the sandy and loamy sandy soil decreased as ph increased. if the rainwater were without any salts, salinomycin will strongly sorbed on to soil, with very little chances of it leaching into ground water. however, it was shown in this study that a phosphate buffer (ph 7) easily desorbed very tightly sorbed salinomycin. since actual rainwater would contain dissolved salts, there is a high likelihood that it may desorb salinomycin, thus posing a greater threat to groundwater and, to some degree, surface water contamination. references berglof t, dung tv, kylin h, nilsson i (2002). carbondazim sorption desorption in vietnamese soils. chemosphere, 48: 267-273. boxall aba, kopin dw, sorensen bh, tolls j (2003). are veterinary medicines causing environmental risks? environ. sci. technol., 37: 286a–294a. carter ap, clemons wm, brodersen de, morgan warren rj, wemberley b t, ramakrishnan v (2000). functional insights from the structure of the 30s ribosomal sub units and its interactions with antibiotics. nature, 407: 340-348. european food safety authority (efsa) (2004). opinion of the scientific panel on additives and products or substances used in animal feed on a request from the commission on the safety and the efficacy of product “bio-cox 120g” as feed additive in accordance with council directive 70/520/eec, 75: 1-51. frestegard a, peterson so, baath e, nielson th (1997). dynamics of microbial community associated with manure hot spots as revealed by phospholipids fatty acid analysis. appl. environ. microbiol., 63: 2224-2237. dobler m (1981). ionophores and their structures. john wiley., hoboken., nj. usa. environmental assessment technical assistance handbook (eia) (1987). march, pp. 3: 87-175. kim s, carlson k (2006). occurrence of ionophore antibiotics in water and sediments of a mixed-landscape watershed. water res., 40: 2549–2560. kolpin dw, furlong et, meyer mt, thurman em, zaugg sd, barber lb, buxton ht (2002). pharmaceuticals, hormones, and other organic wastewater contaminants in u.s. streams, 1999–2000: a national reconnaissance. environ. sci. technol., 36: 1202–1211. kumar k, anita t, asohok ks, chander y, gupta sc (2004). elisa for ultratrace determination of antibiotics in aqueous samples. j. environ. qual., 33: 250–256. loke ml, tjrnelund j, halling sorensen b (2002). determination of the distribution coefficient (log kd) of oxytetracycline tylosin a. olaquindox and metronidazole in manure. chemosphere, 48: 351361. miao xs, mareh re, metcaffe cd (2003). fragmentation study of salinomycin and monensin a antibiotics using electrospray quadrapole time of flight mass spectrometry. rapid commun. mass spectrom., 17: 149-154. paulus ef, kurz m, matter h, vertesy l (1998). solid state and solution structure of the salinomycin sodium complex. stabilization of different conformers for an ionophore in different environments. j. am. chem. soc., 120: 8209-8221. rabolle m, splid nh (2000). sorption and mobility of metronidazole, olaquindox, oxytetracycline and tylosin in soil. chemosphere, 40: 715-722. shen j, brodbolt js (2000). charecterization of ionophore metal complexes by infrared multiphoton photo dissociation and collision activated dissociation in a quadrupole ion trap mass spectrometer. analyst, 125: 641-650. sobott f, kleinkofort w, brutschy b (1997). cation selectivity natural and synthetic ionophores probed with laser induced liquid beam mass spectrometry. anal chem., 69: 3587-3594. trivedy rk, goel pk (1986). chemical and biological methods for water pollution studies. environ. publ., karad. tolls j (2001). sorption of vetenery pharmaceuticals in soils. a rev. am. chem. soc., 35: 3397-3406. volmer da, lock cm (1998). electrospray ionization and collision induced dissocation of antibiotic polyether ionophores. rapid comm. mass spectrom., 12: 157-164. walkey a, black ca (1934). as estimation method for determination of soil organic matter and a propsed modifications of the chromic acid titration method. soil sci., 37: 1409–1421. 1 in ternationa l scholars journa ls african journal of environmental economics and management issn 2375-0707 vol. 11 (1), pp. 001-005, january, 2023. available online at www.internationalscholarsjournals.org © international scholars journals author(s) retain the copyright of this article. full length research paper effect of cement dust pollution on the vascular cambium of juglans regia (l.) bilal ahmad wani* and amina khan wood science laboratory, department of botany university of kashmir, hazratbal, srinagar –190006, india. accepted 15 september, 2022 woody trees increase in girth by the activity of meristematic tissue called vascular cambium. the vascular cambium comprises fusiform and ray initials, which give rise to vertically oriented elements that is, vessels, fibers, tracheids etc. and horizontally oriented elements that is, rays. the present study reveals that there is reduction in dimensions and proportions of fusiform and ray initials in juglans regia growing under impact of cement dust pollution. key words: vascular cambium, cement dust pollution, juglans regia. introduction the activity of vascular cambium is not uniform throughout the year and is determined by the interaction of internal and external factors (philipson et al., 1971; larson 1994; iqbal 1994; grotta et al., 2005) . with rapid industrialization the environment is degrading day by day effecting air, water and soil. the forests are in no way lagging behind in such activity. trees are mostly affected by the air pollution as it changes internal physiology leading to growth inhibition and cause visible injury and death of plant. number of worker have studied the vascular cambium of trees (dave and rao, 1982; ghouse and iqbal 1975, 1977; ghouse et al., 1980; han and woong, 1993; iqbal 1990; khan et al., 1988; khan, 2001; paliwal and yadav, 1999; paliwal et al., 2002; rao and rajput, 1999; rao et al., 1996) but little is known about the activity of vascular cambium in trees growing under pollution (berlyn and battey, 1985; creber and chaloner, 1990; khan, 1982) though a few attempts have been made to explain the formation of xylem in conditions affected by air pollution (bauch, 1986; de kort, 1986; evertsen et al., 1986; ghouse et al., 1984a; b; kottzenburg and knigge, 1987; mahmooduzzafar and iqbal, 1993; mahmooduzzafar et al., 1986; wahimann et al., 1986). keeping in view the *corresponding author. email: arfee.b@rediffmail.com, woodscience.2005@gmail.com. above observations an attempt was made to study the effect of cement dust pollution on the vascular cambium of juglans regia. it is one of the most important temperate dry fruit trees of j and k state, spread over an area of 599.00 ha. producing 83, 399 metric tones of fruit annually (anonymous, 2001) . besides its fruit production, almost every part of tree is useful. the wood is highly prized, used in making of high quality furniture, carving items, cabinets, musical instruments and in rifle butts (gamble, 1972). materials and methods cambial sample along with some bark and sapwood of 1 to 2 inch 2 size were collected from main trunk of j. regia belonging to family juglandaceae growing under the environmental stress of cement dust pollution near khrew cement plant, khrew, district pulwama, kashmir, india while healthy plants growing in natural conditions from wahab sahaib, shar, district, pulwama, kashmir. the geographical location along with other characteristics of the selected sites and material are shown in table 1. twenty samples were taken from 5 trees of comparable age and vigour under one environmental conditions in the same month of the year. samples were fixed on spot in formalin aceto-alcohol (f.a.a) and then transferred to 70% ethanol after 72 h for preservation. samples were sectioned in tangential plane at a thickness of 10 to 15 µm. sections were stained in tannic acid, ferric chloride (foster, 1934) and mounted in canada balsam (sass, 1958). measurements of cambial initials were carried out from tangential longitudinal sections with the help of an ocular micrometer scale under the specific magnification of compound microscope. an average of 500 measurements was 2 table 1. the geographical location along with other characteristics of the selected sites and material. factor site i (khrew) experimental site ii ( shar-i shali) control north latitude 30º 12´ 30º 10´ east longitude 75º 35´ 75º 30´ elevation (m) 1750 2000 soil sandy clay sandy clay age in years 1013 1013 figure 1. a: t. l.s of j. regia in normal environmental conditions showing nonstratified cambium. b: t.l.s of j. regia growing under cement dust pollution. taken on random basis. the mean of cell dimensions were determined after pooling the readings obtained from different samples. the ratio of ray and fusiform initials was calculated by ghouse and iqbal (1975). results the vascular cambium of presently investigated species of j. regia is made up of two type’s initials that is, fusiform and ray initials. the fusiform initials were elongatedspindle shaped elements which overlap with one another at considerable distance thus rendering the cambium non-stratified. the walls of the fusiform initials bear primary pit fields and have distinct plasmodesmata connections with the contiguous elements, especially with the ray initials. the radial walls of fusiform initials are slightly thicker than the tangential ones and appear distinctly beaded during dormancy (figure 1a). the length of fusiform initials ranges from 363 to 414 µm under normal growth conditions and 327 to 378 µm under cement dust pollution. the width of these cells is found to vary from 16 to 21 µm and 14 to 20 µm, respectively (table 2) . the ray initials which occur in distinct groups generally form cambial rays which vary in width and height to a considerable extent in the different environmental conditions (figure 1). two or more cambial rays often fuse together to form complex aggregates running to a great height and covering the length of one or more fusiform initials. a fusiform initial can also intrude into a unit of ray initials by apical intrusive growth thus splitting it into two parts. the size of ray initials also varies in different environmental conditions. the anticlinal and periclinal diameter of these initials ranges from 24/30 24/33 µm in normal 3 table 2. dimensions of cambial initials under different environmental conditions. fusiform initals ray initials length width anticlinal periclinal ratio of fusiform initals to ray condition µm µm µm µm µm range normal 363-414 16-21 24-30 24-33 78/22 pollution 327-378 14-20 23-30 22-31 76/24 trees while in cement dust pollution, it ranges from 23/30 22-31 µm (table 2). depending on the cambial make-up the ratio of ray and fusiform initials differ in different conditions of environment. in normal trees, the ray initials constitute about 22% and that of fusiform initials constitute about 78% while in trees growing in cement dust pollution it constitute about 24 and 76%, respectively. discussion air pollutants, responsible for vegetation injury and crop yield losses, are causing increased concern (fuji, 1973). air pollution has become a major threat to the survival of plants in the industrial areas. rapid industrialization and addition of the toxic substances to the environment are responsible for altering the ecosystem (ara et al., 1991; ahmad et al., 1986). the cement industry also plays a vital role in the imbalances of the environment and produces air pollution hazards. the cement production process is accompanied with the emissions of considerable amounts of dust which causes changes in the growth conditions of forest trees. dust falling from the atmosphere to the forest ecosystem is deposited mostly on leaves (parn, 2006), and effect photosynthesis, stomatal functioning and productivity (nanos and ilias, 2007). the reduced photosynthetic activity retards cambial activity and consequently xylem and phloem production (wahlmann et al., 1986). transpiration rate decreases and assimilation processes are starved of minerals (halbwachs, 1970) . the activity of cambium depends on the availability of water, starch, soluble sugars, minerals and growth hormones etc. (berlyn and battey, 1985; iqbal, 1995; riding and little, 1984. in the presently investigated plants, arrangement of cambial initials depicts a clear nonstratified structure as in the majority of vascular plants (figure 1). in this type of arrangement, the fusiform initials overlap with one another at considerable distance, thus rendering the cambium non-stratified e.g. salix, populus, eucalyptus (dwivedi, 1982). bailey (1923) found that the length of fusiform initials in non-stratified form vary from 460 ti 4440 um. the present observations regarding this aspect do not agree with the limits of bailey’s above observations. bartwal et al. (1983); ghouse and iqbal (1975); ghouse et al. (1980); khan (1980); khan (2001); mahmood (2001) and wani and khan (2008; 2009) have found the length of fusiform initials to fall shorter than the limits for the non –stratified cambium. among the plants of j. regia investigated in the present study, those growing under the influence of cement dust pollution has been found to possess comparatively short fusiform initials than those growing normal conditions. the shortening of fusiform initials is due to decreased transpiration, because water content is reduced in the stem and fusiform initials readjust their dimensions to decrease in size. the short size of fusiform initials is coupled with structural shortening of other features of the bark and wood namely, the size and structure of sieve tube members, vessel elements, xylem and phloem rays and the amount and distribution of parenchyma so as to support the capillary action in the lumen (esau, 2002; fahn, 1997). the present findings go in agreement with earlier workers (creber and chaloner, 1990; ghouse et al., 1985, 1989; iqbal et al., 1987a; b; khan, 1982; mahmooduzzafar et al., 1986; yunus and iqbal, 1996). the analysis of dimensions of ray initials in the present study indicates that they undergo a decrease in the polluted environmental conditions as compared to healthy trees. while, the relative proportion of the ray initials to the fusiform initials has been observed to increase from 22% in normal condition to 24% under cement dust pollution. this clearly shows an increase in the number of ray initials with decrease in their anticlinal and periclinal diameters under the polluted environment (creber and chaloner, 1990; romberger et al., 1993; yunus and iqbal, 1996). earlier workers show that the fusiform initials constitute more than 90% of the cambial cylinder (bailey, 1923; butterfield, 1972; margaris and papadogianni, 1977). but this report goes in agreement with bhat et al. 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pp. 001-008, february, 2020. available online at www.internationalscholarsjournals.org © international scholars journals author(s) retain the copyright of this article. review sustainable development in cameroon’s forestry sector: progress, challenges, and strategies for improvement dieudonne alemagi* faculty of forestry, the university of british columbia, 4612 2424 main mall, vancouver, bc, canada. tel: (604) 822 6092. fax: (604) 822-9104. e-mail: dalemagi@yahoo.co.uk. accepted 11 october, 2019 this paper examines initiatives formulated by the government of cameroon to promote sustainable development within its forestry sector, and proffers a series of policy recommendations for advancing sustainable forest management in cameroon. since the enactment of cameroon’s comprehensive forestry law (law n0. 94/01 of 20th january 1994), which regulated the forestry sector in the country, the government, in particular, the ministry of forests and fauna, has made a series of efforts with relevant ministries, as well as civil society to promote sustainable forest practices within its forestry sector. however, careful evaluation reveals that while these efforts have led to some progress, the sector is still plagued with a series of socio-economic and ecological challenges namely, poverty, corruption, inadequate capital and technical expertise for producing value-added wood products, illegal logging, insufficient university input, inter institutional conflicts, and inadequate monitoring. the paper concludes by advancing a series of recommendations that could be used to promote sustainable forest management in cameroon. key words: sustainable development, forestry sector, sustainable forest management, cameroon. introduction in cameroon, forestry has contributed considerably to the country’s socio-economic arena. forestry operations in cameroon employ between 45,000 and 70,000 people and account for more than 10% of the country’s gdp (ameriei, 2005; alemagi and kozak, 2010; alemagi, 2010a). estimated at 19,631,000 hectares (mbile et al., 2008), cameroon forests which contain high value tropical tree species like baillonella toxisperma and milicia excels is part of the dense tropical rainforest of the congo basin (figure 1) in central africa and products emanating from these forests contributed to 19.8% of cameroon’s merchandised exports between 1990 and 2000 (lebedys, 2004; alemagi and kozak, 2010; alemagi, 2010a). that said, forestry operations in cameroon are associated with a plethora of problems. for instance, unabated logging irrespective of ecological degradation of forested ecosystems is common practice in the country. socio-economically, despite these rich forests that contribute 10% of the country’s gdp, most forest communities of cameroon are poor. the benefits of these rich forests and forestry are not accrued to the local people. in 1994, the government of cameroon enacted a major forestry law (law n0. 94/01 of 20th january 1994), and in the following year, a fundamental decree (decree n0.95531-pm of 23rd august 1995) was formulated and passed to facilitate the implementation of this law (oyono, 2004; alemagi and kozak, 2010). the 1994 forestry law has been cited as the first attempt to decentralize forest management practices and address issues of sustainability and inequity in the congo basin (oyono, 2004, alemagi and kozak, 2010). in fact, since the enactment of this law, efforts have been made by the government and civil society to improve the socioeconomic and ecological sustainability of the forestry industry. however, from a review of the relevant literature, i argue that the efficacy of these initiatives has not been adequately addressed. in other words, while many authors have broached the topic of sustainable forest management in cameroon (for example, kouna, figure 1. map of cameroon and its regions. tree icons represent cameroon’s dense tropical rain forest of the congo basin. (source: adapted from mertens et al., 2001). 2001; efoua, 2001; oyono, 2004; oyono, 2005; oyono et al., 2005; cerutti et al., 2008; clough et al., 2008; cerutti et al., 2010), few have provided answers to the following fundamental questions: (i) what are the impacts of initiatives formulated by the government of cameroon to promote sustainable forest management, and are there any stakeholders that have been neglected in terms of assistance? (ii) is there any accountability and transparency in the management of forest resources? (iii) are there any conflicts between the relevant regulatory institutions? answers to these questions are central to advancing sustainable forest management in cameroon. the purpose of this paper, therefore, is to examine in detail the initiatives that have been formulated by the government of cameroon to promote sustainable development in the forestry sector and to suggest a series of recommendations for advancing sustainable forest management. the study is based on a combination of exploratory interviews with forestry stakeholders, as well as a comprehensive literature review of relevant documentation. the paper provides an overview of the concept of sustainable development within the context of forestry in cameroon and outlines some of the fundamental steps taken by the government and civil society to facilitate improved socio-economic and environmental management in the forestry sector. the discussion highlights some of the major hurdles to sustainable forest management in cameroon. the paper concludes by prescribing recommendations that could be used to advance sustainable practices within cameroon’s forestry sector. profiling sustainable development in the context of forestry the brundtland report emphasises the need for industries to be responsible for their negative environmental impacts and offers a vision for sustainable development which is defined as a development that meets the needs of the present without jeopardizing the requirements of the future generation (wced, 1987). in order to fully adhere to this definition, forests exploitation must not exceed production so that the forests continue to grow to have enough forest resources for future generations. as quoted in karsenty et al. (2008), the united nations forum for forests defines sustainable forest management as the “the stewardship and use of forests and forest lands in a way, and at a rate, that maintains their biodiversity, productivity, regeneration capacity, vitality and their potential to fulfill, now and in the future, relevant ecological, economic and social functions, at table 1. allocation of forested lands in 2007 (reproduced from mbile et al., 2008). forested land use regime area (ha) percentage of total community forests 380764.5 1.9 communal forests 413622.3 2.1 forest licenses 6063457 30.9 forest reserves 1541111 7.9 forest management units 7066647 36.0 sales by standing volume 379745.2 1.9 protected areas 3785653 19.3 total estimated forested land use regime 19631000 100 local, national, and global levels and that does not cause damage to other ecosystems”. thus, since sustainable development involves improvements in the socioeconomic and ecological arena, there is a salient need for stakeholders (forest companies, government, and civil society) to be actively engaged in improving the living standards of the communities, as well as promoting the ecological integrity of the forests in which these communities are situated. as it is explained subsequently in this paper, since the enactment of the main legislative framework (law n0. 94/01 of 20th january 1994) governing cameroon’s forestry sector, the sector has received increased oversight from the government, as well as national and international donor agencies. advancing socio-economic sustainability in cameroon’s forestry sector before proceeding with initiatives undertaken to advance socio-economic sustainability within the forestry sector in cameroon, it is important to briefly discuss forest tenures and governance in cameroon. the majority of cameroon’s forests occur on publicly held lands. specifically, apart from community and communal forest, all forests in the country is owned and administered by the government (table 1). the ministry of forests and fauna (minfof) is the governing body responsible for administering the sale of standing timber – up to a maximum area of 2,500 hectares over a three-year lease – to logging companies owned and operated by cameroonian nationals (minef, 1996; karsenty, 2007; alemagi and kozak, 2010; alemagi, 2010a). in addition, it also oversees the granting of long-term tenures of fifteen years to large-scale logging companies, up to a maximum area of 200,000 ha (minef, 1996; alemagi and kozak, 2010; alemagi, 2010a). the responsibility for granting community forest licenses which confer to local communities, the right to operate a maximum forest area of 5,000 ha with tenure durations of at least 25 years – is also vested in the hands of minfof (minfof, 2009). “as of 2008, there were 135 fully operational community forest licenses in cameroon covering about 2% (621,245.4 ha) of the country’s forest” (mbile et al., 2008; alemagi and kozak, 2010; alemagi, 2010a). by legalizing forestry operations, the government of cameroon has taken a fundamental step toward improving the socio-economic and ecological sustainability of its forestry sector. as kishor and rosenbaum (2003) pointed out, legalization is vital in mitigating unacceptable forest management practices. indeed, effective and efficient implementation of forestry legislation is essential in eliminating operational hurdles that affect sound management and productivity. any person or party that is interested in forest exploitation (especially timber exploitation) in cameroon must apply for a license. according to minef (1996), alemagi and kozak (2010), and alemagi (2010a), for concession-based forestry, the process of acquiring a license starts with the prospective concessionaire (logging company) submitting a file containing ten copies of an administrative and technical bid, as well as a financial bid to the relevant authority in minfof, following a call for public tender by the government. the duration of this advertisement is forty-five days. a forest concession is awarded to the highest bidder by minfof after approval is granted by an inter-ministerial committee. after the successful applicant has paid a caution fee into the state treasury within 45 days, an official order is issued that assigns the forest concession to the concessionaire. apart from a few forest enterprises that are owned and operated by cameroonian nationals, a majority of concessions in cameroon belong to asian and european companies from france, italy, the netherlands, belgium, malaysia, china, hong-kong, and lebanon (karsenty, 2007; alemagi and kozak, 2010; alemagi, 2010a). concession-based forestry remains the dominant business model in cameroon’s forestry sector (alemagi and kozak, 2010). in order to further promote the socioeconomic sustainability of this model, the provision of social services (like schools, hospitals, good roads, and electricity) to the communities in which their logging concessions are located is part of a contract that is negotiated by concessionaires and communities after the logging contract is awarded to a concessionaire by the table 2. forest taxes since the creation of the forest revenues enhancement program (reproduced from tieguhong and betti, 2008). year/period amount of revenue (in billions of fcfa) % increase over 1999 figure 1999 11 2000-2001 27 145 2001-2002 38 245 2002-2003 39 255 state (karsenty, 2007; karsenty et al., 2008). in addition, as a means of providing local employment, concessionaires are also obliged to set up timber processing units within each forest concession (siebock, 2002). law n0. 94/01 of 20th january 1994 ordains that a proportion of royalties collected from logging companies are to be set aside for community development. allocation of these royalties is done in the following manner (oyono, 2005; alemagi and kozak, 2010; alemagi, 2010a): 50% to the state; 40% to the rural council within which the concession is located; and 10% to the neighbouring village communities that accommodates the logging company. furthermore, forest companies are also obliged to pay an “ecotax” of us$1.5 per cubic meter of timber to forest communities in which their concession is situated (milol and pierre, 2001; oyono, 2005). some concessionaires have gone a step further by paying neighbouring communities a voluntary contribution of us$ 1.20–1.60 per cubic-meter of wood that is harvested and sold (massoukou, 2007; karsenty et al. 2008). a fundamental obligation of order no. 00122/minefi/minat of 29th april 1998 is the establishment of a management committee responsible for managing forest royalties in all sub-divisions and villages where forest concessions are situated (alemagi and kozak, 2010). a management committee at the subdivision level is supervised by two administrative authorities (the “sous-prefet” and mayor), while at the level of villages, the committee is headed by a chairman and four to five local residents (oyono et al., 2005; alemagi and kozak, 2010). as a means of combating corruption, generating higher revenue, obtaining greater efficiency, and promoting competition among logging companies, tieguhong and betti, (2008) report that logging concessions are allocated through a competitive bidding process. they assert that in a bid to increase the contribution of forest revenue to the country’s national budget, the government created the forest revenue enhancement program in 1999. as a result of implementing this program, there was a significant increase in the amount of forest revenues (table 2) from 11 billion fca in 1999 to 39 billion fcfa in the 2002-2003 fiscal year (tieguhong and betti, 2008). with respect to community forestry, the licensing procedure for establishing a community forest in cameroon is as follows: minfof (2009) states that any prospective applicant must submit an application file to the divisional delegate responsible for forestry in the area concerned. the file must contain a stamped application that is endorsed by the relevant authority and should layout the objectives ascribed to the proposed forest. in addition, the file must also include a plan revealing the location of the forest, the name of the community forest, a description of previous activities undertaken in the forest, a probationary management agreement form for the forest, a certificate detailing the surface area of the forest and the minutes from public consultation meetings. should this plan be endorsed, a probationary license is issued which permit the applicant to manage the forest for a three year period. after this period, the applicant must submit a simple management plan for review and approval before a permanent license is issued. this license is valid for at least 25 years. section 37 (3) of law n0. 94/01 of 20th january 1994 stipulates that, in a community forest, timber, non timber forest products, wildlife and fishery resources (except those forbidden by law) belong to the communities (minfof 2009). thus, communities have the right to exploit these resources and use the proceeds for community development. besides, all activities in a community forest must comply with the provisions of a simple management plan. the plan among other things documents the resources available in the forest, the activities that are envisaged in the forest and the contribution of the forest to socio-economic development within the community in which the forest is located (minfof, 2009). mbile et al. (2008) report that international funding agencies like the british department of international development (dfid), the netherlands development agency (snv), and other locally-based non governmental organizations (ngos) have developed capacity building projects to facilitate the effective implementation of community forest projects in cameroon. they note that the efforts of these international donor agencies have been impressive, particularly in lomié (southeast cameroon), where there is a strong network of local ngos (like caft – trinational agroforestry cooperative) that are guiding and training villagers in community forest management. advancing ecological sustainability in cameroon’s forestry sector with assistance and administrative leadership from organizations like global witness, minfof has established an urgent action program (uap) and the national brigade for the control of forests and wildlife which is responsible for monitoring and regulating illegal logging in forest concessions (tieguhong and betti, 2008; alemagi and kozak, 2010). on may 6 2010, the government of cameroon also signed a voluntary partnership agreement with the european union (eu) that aims to ensure that legal harvested timber is sold in cameroonian markets, as well as other eu countries when it is exported (fern, 2010). more to the point, there are other legal instruments designed by international bodies to fight illegal logging in cameroon like the forest law enforcement governance and trade (flegt) action plan of the eu. efforts have also been made by civil society nationwide to reduce the problem of illegal logging in cameroon. a classical example is the application of satellite imageries and the geographic information system (gis) to identify illicit operations within forest concessions in the southeast region of cameroon by the german agency for technical cooperation (gtz) (pandya, 2002, alemagi and kozak, 2010). additionally, the government has instituted an assortment of supporting and monitoring services like verification points on roads and regular auditing and monitoring at sawmills to tract down illegal logging operations (pandya, 2002). after a forest concession is allocated to the highest bidding company, the company is given three years to prepare a forest management plan (fmp), and once approved, the plan must be revised after every five years (minef, 1996; cerutti et al., 2008; alemagi, 2010a). as cerutti et al. (2008) explains, a fmp is a comprehensive document in which the potentials of forest resources are assessed, trade-offs among the ecological and socioeconomic aspects of forest management are evaluated, and equitable solutions are proferred. as of 2007, about 3.5 million hectares of forests in cameroon were managed using approved fmp (minfof, 2007; cerutti et al., 2008; alemagi, 2010a). it is also important to note that procedures for preparing a fmp are prescribed in order n 0 0222/a/minef of 25th may 2001(alemagi, 2010a). more importantly, article 33 of this law stipulates that the commission that is responsible for assessing fmp must confirm and validate a logging company’s choice regarding (i) tree species identified for management (ii) the logging cycle, and (iii) calculations used to determine the annual allowable cut (minef, 2001). the use of a simple management plan to promote replanting of havested tree species within community forests is recommended in the manual of the procedures for the attribution, and norms for the management of community forests in cameroon. specifically, section 7.9 of the manual reads: “while implementing a simple management plan, the community must undertake operations aiming at ensuring the maintenance of the ecological potential of their forest. such actions, namely conservation and regeneration activities, must be in line with a simple management plan” (minfof, 2009).” monitoring is also necessary to ensure legal compliance. in cameroon, local communities and minfof share the responsibility for monitoring illicit activities within community forests (alemagi, 2010b). finally, other important efforts that have been made by the government to promote biodiversity conservation within the forestry sector include the creation of nature reserves, national parks, and zoological gardens. by 2008, the government had created 14 national parks, 7 wildlife reserves, 3 zoological gardens, and 1 gorilla sanctuary (tieguhong and betti, 2008). discussion given all the initiatives undertaken by the government to advance socio-economic and ecological sustainability in the forestry sector, it might be tempting to conclude that these actions have been successful in achieving significant socio-economic and ecological outcomes in the forestry sector. in fact, such a conclusion would be fundamentally flawed. as detailed in this sector of the paper, a considerable number of challenges to sustainable forest management still prevail within cameroon’s forestry sector. most concessionaires in cameroon are foreign-owned (karsenty, 2007; alemagi, 2010a; alemagi and kozak, 2010). to this end, very little of the enormous wealth that they do generate is used in the establishment of social services in the communities in which they are operating (the rainforests foundation and forests monitor, 2007; alemagi, 2010a). many have noted that the two main beneficiaries of these revenues are the government and the forest products firms (oyono, 2005; njoh, 2007; alemagi, 2010a). as a result, poverty remains endemic in most forest communities that accommodate logging concessions belonging to these firms. “during field visits to some of these communities in the southwest and east region of the country in march 2009, it was noticed that basic social amenities like schools, hospitals, electricity and good roads are fundamentally lacking” (alemagi, 2010a). in addition, during field visits to the southwest region of cameroon in march 2009, it was also witnessed that although two large-scale forest products companies controlled logging concessions in the communities of kembong, ewelle і and іі, ajayukndip, ossing, talangaye, okoroba, mbinda, and bakogo neither actually operated sawmills in the communities implying that they provided little in the way of local employment, two principal reasons underpin the forest-poverty trap in cameroon. first, many concessionaires may not be meeting their obligations with respect to corporate social responsibility (alemagi, 2010a). for example, mindourou – a town in the east region of the countrylacks electricity, while nearby concessionaires have access to private electricity (alemagi, 2010a; alemagi and kozak, 2010). second, even though the prevailing legal disposition mandates that 10% of forest royalties be apportioned to forest communities within which forest concessions are situated (oyono, 2005; alemagi, 2010a; alemagi and kozak, 2010), the communities contend that this proportion is inadequate (oyono et al. 2005; alemagi, 2010a; alemagi and kozak, 2010) and cannot provide the infrastructure required for sustainable societal development. a head of civil society in an aboriginal community in the east region of the country provided a more accurate account of this problem during a personal discussion: “after all these tours you can see for yourself that these forest-dependent communities are poor. look at the type of houses where people are living in.... these are rather huts and not houses... in all the communities that we have visted there is no electricity as you have seen, look at how bad the roads are.. in the raining season it is horrible ... it is true that the council has used some of the money from the government to build schools in some of these villages but this money is surely not enough and not well spend ..... otherwise there will be signs of development in these communities....” furthermore, it is reported that corruption and embezzlement of forest royalties by members of the sub-division and village management committees situated in the east region of cameroon are common (assembe, 2001; efoua, 2001; kouna, 2001; oyono, 2001; oyono et al., 2005; alemagi, 2010a; alemagi and kozak, 2010). in a report entitled “a forest policy context and case study analysis to support alternative tenure and enterprise options for trees and forest resources management in cameroon” written by mbile et al. (2008) for rights and resources initiative, it is reported that the major problems faced by community forest operations (cfos) in cameroon include, inter alia, limited size for community forests, inefficient equipment and machinery, insufficient working capital, insecurity in prices of forest products, and inadequate technical expertise. however, inadequate working capital and technical expertise for producing value-added wood products is the main concern. during personal discussions with heads of civil society in the east, southwest, and littoral regions of the country, it was revealed that because of inadequate expertise and financial resources, most cfos are unable to add value to timber and non-timber forest products. the importance of valued-added wood products as a means of achieving socio-economic and ecological sustainability cannot be over emphasized. as kozak (2007) explains, by producing value-added wood products, more jobs are created per unit of wood harvested and this constitutes a robust strategy for striking a fair balance between socio-economic well-being and ecological sustainability. it was also interesting to note that the university of dschangthe only university in cameroon that offers forestryhas minimal involvement in research in the forestry sector. during personal communications with personnel at this university in march 2009, it was reported that most of the few research projects in the university are crafted and masterminded by faculty and students with minimal assistance from the government and the forest products companies. in reality, the university of dschang like any other local university in the country competes with industries and civil society for limited funds from the government. as a result, this institution is underfunded and lacks the state-of-the-art facilities for undertaking forestry research. conflicts are prevalent in cameroon and have eventually led to unsustainable forest management. to say the least, conflicts do not help in promoting sustainable forest practices. in cameroon, “the ministry of environment and nature protection (minep) has the mandate to articulate, execute, and assess the government’s policy in relation to the environment” (republic of cameroon, 2005; alemagi and kozak, 2010). however, as alemagi and kozak (2010) explain, the forestry sector and its policy is enacted, assessed, and implemented by a different ministry, minfof. clearly, there is an overlap in the functions of these ministries as both compete to implement cameroon’s environmental policies. this has resulted in interministerial conflicts between these two ministries. as quoted in alemagi and kozak (2010), one government official in minfof explained that: “we are trying to stop this illegal logging, but still, we have conflicts at times with another ministry like minep, especially when you look at the problem of environmental impact assessment (eia) in the forestry area that is validated by minep and not us. this is a problem.” nguemdjom (2006) notes that timber extraction from most forest concessions in cameroon is unsustainable from an ecological point of view, with estimates of the annual forest loss of cameroon forests being 1%. additionally, it is reported that illegal logging is common within most concessions belonging to large-scale logging companies in cameroon (amariei, 2005; clough et al., 2008; alemagi and kozak, 2010). the fundamental rationale behind this ecological issue is that the minfof which is responsible for monitoring illegal operations within cameroon’s forests is faced with logistical issues. specifically, during field visits to eyumojock subdivision in the southwest region of the country in march 2009, it was noted during a personal conversation with the traditional head of a village community that the whole of this subdivision was staffed with only one permanent forestry personnel. additionally, in another personal discussion with an authority at the regional delegation of forests and fauna in buea capital of the southwest regionit was understood that the divisional delegate of forests and fauna for fako division did not have a service car. recommendations and conclusions the foregoing section has identified and discussed the major challenges to sustainable forest management in cameroon. recognizing these dilemmas, this section of the paper proffers some important recommendations for policy makers to consider as they attempt to advance sustainable forest management in the country. 1) to tackle corrupt practices in the forestry sector, accountability, transparency, and democracy must be promoted and employed in managing forest resources and the royalties obtained from them (alemagi, 2010; alemagi and kozak, 2010). 2) results of this study also point to a pressing need for the government to be more proactive in making sure that the social and environmental obligations of forestry companies are fulfilled for the benefit of the communities in which they are located. as alemagi (2010a) opine, this could be achieved by promoting the importance of checks and balances in the enforcement of responsible corporate practices. 3) the government and civil society should provide support to business operations that are engaged in the production of value-added wood products. indeed, support could be in the form of financial incentives, training and education with regards to the sustainability of value-added wood products. 4) this paper also presses the need for the government to promote fundamental and strategic research in local universities, especially research geared towards developing improved socio-economic and environmental management practices within the forestry sector. more specifically, relevant ministries like minfof and minep should form forestry research partnerships with the university of dschang. 5) adequate monitoring is highly recommended if sustainable forest management is to be achieved in cameroon. indeed, in the absence of sufficient monitoring, enforcement of laws geared at promoting sustainable forest management is difficult. 6) it is time to re-examine the responsibilities of the relevant ministries that are responsible for forest management in cameroon to ensure that conflicting responsibilities are streamlined in order to eradicate the current overlaps. 7) immediately suspend or revoke forestry licenses given to forest product firms that violate forestry regulations. this will serve as a deterrent to defaulters and will help to ensure that communities obtain a fair share of proceeds emanating from forestry operations. in summary, the promotion of transparency and local democracy in the management of forests resources, support for value-added wood manufacturing, research contribution from local universities, adequate monitoring, a redress of conflicting institutional responsibilities, and a suspension or revocation of licenses belonging to defaulting forestry companies are keys to advancing sustainable development in cameroon’s forestry sector. a series of fundamental initiatives have already been undertaken by the government to advance socioeconomic and ecological sustainability in the forestry sector. however, implementation of the aforementioned recommendations by all the relevant stakeholders will certainly go a long way to promote sustainable forest management in cameroon. acknowledgements the author would like to thank heads of civil society in forest-dependent communities of cameroon for giving their valuable time to participate in discussions about forest management in their communities. this study was funded principally by the social sciences and humanities research council of canada. references alemagi d, kozak ra (2010). illegal logging in cameroon: causes and the path forward. forest policy econ., 12(8): 554-561. alemagi d (2010a). a critical analysis of concession-based forestry: the case of cameroon in central africa. in: frank columbus, ed. advances in 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update, 18(1): 6-9. wced (1987). our common future. oxford university press: oxford. in ternationa l scholars journa ls african journal of environmental economics and management issn 2375-0707 vol. 5 (3), pp. 290-301, march, 2017. available online at www.internationalscholarsjournals.org © international scholars journals author(s) retain the copyright of this article. full length research paper a study of the security concerns and policies of asian developing countries with regard to sustainable development and impact of nuclear energy devi rani bindu school for environmental sciences, babasaheb bhimrao ambedkar university, lucknow, uttar pradesh, india. email. devi_ranibindu_0@yahoo.com. accepted 02 december, 2016 the problem of global climate change will be solved by meeting stringent, long-term policy targets that are much more ambitious than the short-term, greenhouse gas emission reductions that some countries currently attempt to reach. the large-scale implementation of carbon-free technologies constitutes one of the measures essential to realize the mitigation of global warming. nuclear power generation involves no carbon dioxide emissions, but the current use of nuclear energy cannot be considered sustainable. however, in attempting to achieve sustainable development and to establish transition paths towards sustainable energy systems in particular nuclear energy might, for the moment, need to remain a component of the global energy mix. asian developing countries, aspiring to embark upon paths of rapid economic growth and to increase levels of welfare, should carefully consider the relatively high costs involved in the development of nuclear power when designing long-term, sustainable, and affordable energy infrastructure. this paper argues that if countries such as china and india continue to expand the use of nuclear energy, they would do better not to choose a nuclear fuel cycle based on reprocessing, but to adopt a once-through fuel cycle instead. keywords: nuclear energy, sustainability, global climate, fossil fuel. introduction nuclear energy remains a controversial issue for policymaking on energy and environment because of arguments concerning radioactive waste, reactor accidents, nuclear proliferation, economic competitiveness, and public opinion. the issues of climate change and supply security have provided a new rationale for its reappearance on the international political agenda. recent national policy directions in some countries show that such a potential comeback of nuclear energy is not just wishful thinking of the nuclear establishment. because nuclear energy currently faces stagnation, it is unrealistic to consider it a serious option for significantly reducing carbon emissions in the short run. on the other hand, it seems a mistake to exclude at this time any of the available options including nuclear power -that could possibly contribute to mitigating emissions of ghgs (greenhouse gases) in the longer run. whether or not nuclear energy will play a role of significance in the long term, all energy technologies including nuclear ones -ought to be considered in terms of their potential to contribute to goals of sustainable development, including aspects related to environmental, economic, and social risks, particularly climate change prevention and supply security support. it is widely recognized that, in addition to other factors, the availability and use of electricity can improve the standard of living in developing countries and, in fact, may be an indispensable driver of economic and social progress (iea 2002). economic growth towards higher levels of wealth in these countries is intimately linked to increases in per capita utilization of energy. however, in attempting to establish effective, efficient, affordable, and sustainable energy production and consumption in the developing world, one must be careful not to automatically bindu 291 transpose to developing countries existing energy technologies, infrastructures, and modi operandi as currently employed in developed countries. the resourcerelated, technological, cultural, legal, and societal differences between developing and developed countries should be carefully contemplated and integrated into the design of energy systems in the developing world. many consider the lack of proper energy facilities in the developing world as one of the world's prime development problems, to be tackled on priority. the solution lies in an intelligent, regional probably decentralized approach, which takes into account local needs, capabilities, and customs. in this context, the question is what the future role of nuclear energy may be in addressing the energy challenges of the 21st century in developing countries, particularly in asia. this article provides an overview of some of the main issues concerning the prospects for nuclear energy in asian developing countries, and presents some perspectives of nuclear development in china and india—however different these two countries may be from a nuclear point of view. in these countries, the expertise required for nuclear expansion is available; their governments too are firm in their efforts to enlarge the deployment of nuclear power capacity. this paper discusses whether it is wise to let nuclear energy increasingly contribute to domestic power generation in china and india, and how the share of national nuclear power production is likely to develop. some recommendations are given on how potential nuclear development, if deemed necessary, could best be pursued. after providing this outlook on the global future use of energy and the role of fossil fuels and energy supply security therein, the chapter puts nuclear energy into the perspective of sustainable development and presents the results of a simple scenario analysis, through which the merits of nuclear energy can be assessed in terms of climate change control. it goes on to describe some elements relevant for the economics of nuclear energy and, in particular, of reprocessing of spent nuclear fuel. it then analyses the potential role of nuclear power in asia, takes up two detailed cases of china and india, and concludes. data and methodology the present study is analytical study based on secondary sources of data and information. the data and information have been compiled from economic survey of india, report on trend and progress of natural resource management commission ,basic statistical returns relating to energy consumption in india .for the preparation of present study various journals, magazines and newspapers like indian journal of energy and environment ,economic and political weekly, financial express, economic times etc. have also been used .the period has been chosen considering the availability and consistency of data. global fossil energy outlook the global fossil resource base is abundant and estimated at approximately 5000 gtoe (gigatonnes of oil equivalent) (rogner 1997). given that the current global primary energy use amounts to approximately 10 gtoe per year, this amount is largely sufficient to fuel the world economy throughout the 21st century, even if demand rises significantly. of course, the geological existence of large hydrocarbon resources does not necessarily guarantee energy supply stability or security. energy supply uncertainties exist for many reasons. first, these uncertainties concern the costs of resource recovery and conversion to usable fuels. second, hydrocarbon development and production decisions often lie with public sector agencies and are therefore not driven by market considerations alone, but by international political arguments as well. temporary energy supply shortages and volatile market prices will thus continue to mark the development of the energy system, and it is unlikely that the development of that system will be less volatile in the future than it has been in the past. most important, however, the largest source of energy supply uncertainty seems to be the environment. the co2 (carbon dioxide) emissions from the combustion of fossil fuels constitute the main reason for the increase of the atmospheric ghg concentration. this increase results in a higher global average temperature of the earth's surface, leading to regional and local effects of climate change. the combustion of fossil fuels especially coal is also the cause of various forms of air pollution, with detrimental effects for both human health and the natural environment. the environment is likely to constrain the use of fossil fuels long before global resource scarcity comes into play, so that resource availability limitations are unlikely to drive the global energy system away from a continued reliance on fossil resources. if humankind wants to avoid destabilizing the global climate and preserve local air quality, it will need to operationalize environmental policies, such as the implementation of full-cost pricing, that is, the internalization of the external costs of energy production. resource constraints are unlikely to drive down hydrocarbon production during the 21st century, if technological progress continues to improve productivity—a phenomenon incessantly observed in the past. oil production from existing, recoverable oil reserves is expected to peak within a few decades, but this will at some point spur the development of alternatives, such as the transformation of currently uncertain conventional oil or marginal unconventional oil into the conventional oil of the future. the oil era is thus 292 afr. j. environ. econ. manage. likely to last well beyond the time frame suggested by the currently known, recoverable, conventional crude oil reserves. with global demand for oil rising, pressure on oil prices can be expected in the long run. at times, volatile fluctuations of oil prices may well be encountered, with alternating periods of rapidly increasing and decreasing price movements, around an otherwise longterm trend of gradually rising production costs. however, the volatility fluctuations are unlikely to be caused by resource scarcity, rather by the time lags between market signals such as prices and the point in time when new exploration investments become production-effective. in addition to conventional and unconventional oil, there are large amounts of natural gas and coal recoverable from the earth's crust. from an aggregate carbon quantity-cost curve for the total global fossil resource base, one can deduct that for a maximum of 40 dollars (1990) per barrel of oil equivalent, most of the global fossil resource base is recoverable from the earth when some (modest) level of technological progress over a 100-year period is anticipated (rogner 1997). this underlines the likelihood that fossil fuels remain the predominant form of energy use throughout the 21st century. until 2100, however, humankind may have emitted an amount nearing 2000 gtc (gigatonnes of carbon) into the atmosphere, which pushes the atmospheric co2 concentration to a level well above the 700 ppmv (parts per million by volume)—more than double the pre-industrial concentrations. such an increase will almost undoubtedly imply considerable impacts on living conditions and the environment as a result of climate change. the industrialized world is today responsible for the majority of co2 emissions. if humankind is to stabilize atmospheric co2 concentrations at a level that prevents a dangerous human interference with the climate system, then the developing countries need to be engaged in efforts to limit and reduce ghg emissions. these emissions are growing much faster in developing countries than in industrialized countries, more as a result of economic growth than population growth. to help maintain stability in the world's climate system, (especially) asian countries such as china and india must, as their economies and populations grow, fuel their development with not only economically competitive but also clean energy technologies (wirth, boyden, and podesta 2003). asia will experience the most rapid energy demand increase among all world regions because of its expected robust economic growth over the coming decades. the most important environmental issues for the asian region are local. to control local environmental pollution, as well as co2 emissions, the best strategies for asia focus on rapid technological progress and the use of energy resources other than coal (iiasa and wec 1998). in 2030, the world energy system will probably continue to be dominated by fossil fuels, with a continued proportion of 80%-90% of total energy supply. oil will probably remain the main source of energy (with an expected 34%), followed by coal (28%), while natural gas is projected to represent some 25% of global energy supply by then (ec, iepe, bfp, et al. 2003). coal is fuelling the largest share of power generation worldwide and will most likely supply an increasing percentage of the growth in demand in the future, particularly in the developing world. over the coming 30 years, about twothirds of the increase in coal supply will, in all probability, come from china and india. because of the abundant coal resources in asia, the share of its coal usage remains high (42%) and will not change significantly. in contrast, the shares of oil and gas increase rapidly at the expense of biomass that is almost phased out (probably dipping to around 6% of primary energy consumption in 2030, compared to 30% in 1990). by 2010, asia will be the world's largest consumer of primary energy. by 2020, china and india are expected to produce more carbon emissions than the us and the european union combined. asia already imports around 60% of its oil from the middle east, and asian dependence on this volatile region is increasing (manning 2000). this dependence is a growing concern for asian governments, which view energy largely in strategic terms as a matter of fundamental national security. in the asian region, over the past 25 years, there has been a general decrease in the energy intensity of the gross domestic product, driven both by structural and technological factors (datt, kacker, mehra, et al. 2002). this decrease has been beneficial for the development of a sustainable energy sector in asia. in the areas of improving access to modern energy forms and arresting adverse environmental impacts of energy development, progress has been less impressive. the trend towards the use of economic instruments to support environmental legislation needs to be strengthened, while the role of governments in improving access to energy needs to be enhanced. still, in the coming decades, countries like china and india are not likely to realize a share of commercial energy production from renewable energy resources much beyond the 1% level. this brings up the question of the extent to which nuclear energy could contribute to establishing transition paths towards sustainable energy infrastructures in asia china and india in particular over the decades to come. nuclear energy and sustainability only recently has nuclear energy been subjected to detailed studies in terms of its potential contribution to establishing sustainable development (see, for example, nea 2000; rogner 2001). most analysts confirm that nuclear energy currently does not meet some essential requirements for representing a sustainable energy resource (see, for example, bruggink and van der zwaan bindu 293 2002) and that, in particular, the current use of lwr (light water reactor) technology cannot be qualified as sustainable (rothwell and van der zwaan 2003). arguments concerning radioactive waste, reactor accidents, nuclear proliferation and terrorism, and economic competitiveness all feature in the discussion on the sustainability of nuclear energy. likewise, however, it has been pointed out that it is hard to claim that any of the existing, so-called ‘renewables’ meet all the criteria of a sustainable energy resource (bruggink and van der zwaan 2002). one of the major reasons is that renewables have so far not been applied on a large (global) scale, so that the risks involved in their usage cannot yet be apparent. fundamental issues determining the (un)sustainability of renewables relate to land usage, materials usage, waste production, and environmental impact. while it is not recognized as a sustainable energy resource today, nuclear energy along with other currently available energy options -could play a transitional role towards establishing sustainable energy systems. whereas changes in energy infrastructures, particularly nuclear ones, generally occur relatively slowly, nuclear energy should still be viewed in a dynamic way. during a transitional phase with some role for nuclear power, some of the more problematic aspects of nuclear energy might be rendered more sustainable through, for instance, waste minimization, accident reduction, proliferation control, resource use optimization, and enhancement of economic competitiveness (rothwell and van der zwaan 2003). over the past few decades, technological developments in the nuclear field have been considerable, demonstrated, for instance, by the substantially declining likelihood since the 1986 chernobyl catastrophe of experiencing another serious reactor accident with significant consequences for the external environment. these technological advancements are likely to continue, for instance with respect to increasing reactor safety, reducing radioactive waste lifetime and toxicity, or building more proliferationresistant reactors. this could give nuclear energy a potential role beyond the aforementioned transition period. to some extent, depending on perspectives of both time and location, nuclear energy could contribute to establishing paths towards sustainable energy systems and thereby to achieving sustainable development. in the past, an important reason for developing domestic nuclear energy capacity was its potential to greatly enhance national energy independence, mainly since nuclear fuel (uranium) is widely available and can be cheaply acquired and easily stored. arguments of energy supply security will continue to motivate countries, including those in the developing world with currently modest or absent shares of nuclear energy in electricity production, to develop domestic nuclear power facilities. since the subject of climate change mitigation has been recognized as one of the most significant existing global challenges, nuclear energy has received renewed consideration. as will be pointed out later, whereas even a massive global expansion of nuclear energy would not be a panacea for the problem of global warming, its potential share in controlling atmospheric temperature increases could be significant (sailor, bodansky, braun, et al. 2000; van der zwaan 2002). given the size of the global change challenge, nuclear energy might indeed deserve increased attention. nuclear power might need to be expanded on a global scale, or at least should not be left out of the current energy mix. developing countries could, in principle, play roles in continued and, perhaps, intensified employment of nuclear fission. nuclear energy and climate change through a simple scenario analysis, one can readily estimate the global potential of nuclear energy in reducing carbon emissions and, hence, in mitigating global warming. in other words, if for ease of analysis, one momentarily discards (still important) questions regarding the feasibility and desirability of a large increase in nuclear energy use, what then are the climate-change-related merits of nuclear power when it is expanded massively? since today, about one-third of total global commercial primary energy is supplied in the form of electricity, an answer in first approximation to this question would be that for the moment nuclear energy would not readily be able to reduce carbon emissions by much more than one-third (since nuclear energy is today primarily available through power generation). suppose, in a slightly more detailed analysis, that the current ‘400 ej (exajoules) world’ is expanded over the coming 75 years to one that consumes 1200 ej per year. currently, three fossil fuels together fulfil the major portion of commercial primary energy supply (approximately 86%, responsible today for around 6 gtc per year of emissions), while hydropower, nuclear fission, and renewables account for shares of about 7%, 6%, and 1%, respectively. let us make the stylized assumptions that the use of fossil fuels is decarbonized, by 2075, to the level of the current carbon intensity of natural gas power generation, and that global energy consumption (total, and specified by resource) increases, in two scenarios (i and ii), according to the factors stated in table 1. (for a more extensive description of the corresponding analysis, see van der zwaan [2002]).1 the main features of the scenario analysis according to table 1 are that hydropower retains its relative share of energy supply, over the 2000-75 period, while the use of renewables is ambitiously assumed to increase by a factor of 100 over this time frame. nuclear energy is supposed to stagnate at its current absolute level in scenario i, while it is expanded by the hypothetical factor of 10 in scenario ii. table 2 shows the results of a corresponding exercise in table 1. expansion factors of total energy demand and of the non-carbon emitting hydropower, renewables, and nuclear energy supplies, in scenarios i and ii energy expansion factors scenario i scenario ii total energy 3 3 demand hydropower 3 3 renewables 100 100 nuclear energy 1 10 table 2. annual and cumulative carbon emissions in a simple energy scenario analysis economics of reprocessing and recycling in lwrs (light water reactors) and fbrs (fast breeder reactors) compared to that of the once-through cycle (directdisposal of spentfuel) in lwrs scenario i scenario ii difference annual emissions in 2075 7.7gtc a per year 5.3 gtc per year 31% cumulative emissions over 2000-75 549 gtc 440 gtc 20% break-even price uranium ($/kgu) increase electricity costs (mills/kwh) reprocessing in lwr 360 1.3 reprocessing in fbr 340 7 source bunn, fetter, holdren, et al. (2003) a gigatonnes of carbon terms of annual and cumulative carbon emissions over the period considered, in a comparison between scenarios i and ii. one concludes that if nuclear energy were expanded ten-fold, it could contribute significantly to reducing carbon emissions. such an expansion could avoid about 20% of cumulative co2 emissions over the period 200075, while annual emissions in 2075 would be reduced by about 30%. still, it is evident from this calculation that nuclear energy can be no panacea for global warming. even with massive expansion, nuclear energy should be complemented by drastic fossil fuel decarbonization and massive renewables development, preferably in combination with far-reaching efficiency and savings measures, to attain an emission profile involving a carbon reduction down to one-third of the current level during the latter half of the 21st century (and to lower values after that).figure 1 demonstrates, through a comparison of the two scenarios, the potential significance of a huge expansion of nuclear power in terms of total energyrelated (annual and cumulative) carbon emissions. nuclear economics the costs and capital intensity of electricity generation alternatives are essential determinants for energy policy decisions, more so for developing countries than for countries in the industrialized world. whereas nuclear energy has proven its ability to compete with other (fossil) alternatives in a few cases, on a global level it has never done so in a convincing manner. in the current context of liberalizing electricity markets, the capital intensity of nuclear power constitutes an increasing economic disadvantage. also the intrinsic uncertainties and liabilities of nuclear power generation (related, for instance, to radioactive waste, decommissioning, and reactor safety) render nuclear energy economically unattractive. on the other hand, once nuclear power plants are fully depreciated typically after 30 years of operation their low fuel costs imply that reactors become competitive on a marginal-cost basis, even in a deregulated environment. another aspect in favour of nuclear energy is that its negative environmental 294 afr. j. environ. econ. manage. bindu 295 (a) (b) figure 1. a. energy-related carbon emissions (gigatonnes per year), from 2000 to 2075. b. monte carlo analysis of the break-even uranium price as a function of the cost of reprocessing, for various sets of assumptions about the cost of other fuel-cycle services source bunn, fetter, holdren, et al. (2003) externalities have been more extensively included in electricity costs than in the case of its fossil-based counterparts. like for most renewable energy resources, and unlike for fossil fuel energy systems, the external costs of nuclear energy are expected to be small (rabl 2001).3 proper internalization of negative externalities for all energy resources would thus probably reinforce the competitiveness of nuclear energy. two possible caveats in this respect, for nuclear energy, are perhaps reactor accidents and nuclear proliferation. as for large reactor accidents with major external radioactivity pollution, a justified argument can be made that the environmental costs corresponding to the resulting radioactive contamination damage can be very substantial. in the external cost calculations of rabl (2001), reactor accidents and their effects have been included. only, their contribution to total costs proves small, as a result of their relatively low occurrence. since the earliest days of the nuclear era, another aspect unfavourable to nuclear power has been the prevention of nuclear (military) proliferation. the related costs are not accounted for in externality calculations, partly because it appears difficult to do so, and partly because it appears controversial how to do so. for example, the costs required for maintaining international institutions such as the international atomic energy agency, designed to warrant the civil use only of nuclear energy, are not included in external costs. but since these are small in comparison to other (external) costs, this omission probably does not affect the end result of external cost calculations. how does one go about dealing with the expenditures of the (nuclear) military build-up of one country in response to the acquisition of nuclear weapons by another? the corresponding costs are surely not accounted for in electricity prices or external costs, however much the civil use of nuclear energy opens the door to its military use. since the 9/11 attacks in 2001 on new york and washington, dc, public and political fear has been expressed regarding the use of nuclear fission or radiological devices by terrorists. among potential radiological threats are those involving material or facilities related to the civil nuclear power industry. terrorist risks to nuclear power plants and spent fuel cooling ponds may be considered especially high (alvarez, beyea, janberg, et al. 2003; van der zwaan 2003), and costs to enhance security against terrorist attacks (supposing that through heightened security measures such attacks, and their potential results in terms of costs incurred, can be avoided) should be taken into account in and are unfavourable for the economics of nuclear energy.4 if a country decides to develop a civil nuclear power programme that is, if it chooses to do so after having thoroughly weighed the costs against the benefits of starting off and maintaining such a programme it still needs to make a careful cost-benefit analysis of the various nuclear options available, especially with regard to the adoption of an open or closed nuclear fuel cycle. there is general agreement on the fact that with today's low uranium and enrichment prices, the reprocessing and recycling option (allowing to close the nuclear fuel cycle) is more expensive than the alternative of direct disposal of spent fuel (implying an open fuel cycle). arguments exist, however, over the magnitude of the difference, and how long this difference is likely to hold. advocates of reprocessing often argue that the extra cost of reprocessing is small today, and might soon disappear, as uranium supplies become scarce and their prices rise. in some recent studies, by contrast, it is demonstrated that the margin between the cost of the closed fuel cycle and that of the direct disposal option is wide, and is likely to persist for many decades to come, if not longer (mit 2003; bunn, fetter, holdren, et al. 2003).for example, with central estimates for key fuel-cycle parameters, reprocessing and recycling plutonium in existing lwrs will be more expensive than direct disposal of spent fuel until the uranium price reaches over 360 dollars per kgu (per kilogram of uranium). this price is not likely to be seen for many decades, as current uranium prices are about an order of magnitude smaller (typically 40 dollars per kgu or lower). with reprocessing and recycling of plutonium, the electricity cost would be increased by some 0.13 dollar-cents (1.3 mills) per kwh (kilowatthour), compared to a total back-end cost for direct disposal of about 1.5 mills per kwh. with central estimates for key fuel-cycle parameters, reprocessing, and recycling plutonium in fbrs (fast breeder reactors) (involving an additional capital cost, compared to new lwrs, of 200 dollars per kwe (kilowatt-electric) will not be economically competitive with a once-through cycle in lwrs until the price of uranium reaches around 340 dollars per kgu. electricity from a plutonium-recycling fbr would cost over 7 mills per kwh more than electricity produced with a once-through lwr (table 3). the findings of table 3 are obtained through detailed calculations that include assumptions on all parameters determining the costs of nuclear power through either of the two types of fuel cycle. by how much would the costs of the various parameters have to change in order to significantly modify the results on the economics of reprocessing and recycling in lwrs and fbrs in comparison to that of the once-through cycle in lwrs? figure 2 provides the answer through an illustration of the results of a monte carlo analysis of the break-even uranium price as a function of the cost of reprocessing, for various sets of assumptions about the cost of all main fuel-cycle services. it is evident that even when optimistic assumptions are made regarding the costs of all elements of the entire reprocessing cycle, it remains difficult to reach values of the uranium break-even price that approximate prices at which uranium can today be purchased on commercial markets. the economics of reprocessing is an increasingly important issue, since some countries in both the industrialized and developing worlds need to take major decisions on the future management of their spent fuel. for developing countries like china and india, particularly, the high costs involved in reprocessing and recycling must be given careful consideration, now that important decisions regarding the possible construction of large commercial reprocessing facilities in these countries are soon to be taken. of course, economics is not the only factor determining whether or not a country should close the fuel cycle through the establishment of a reprocessing industry. other arguments matter, such as the property of reprocessing to enhance (uranium) resource efficiency. more pertinently, reprocessing may lead to substantial reductions in the overall volume of waste production (for example, per unit of electricity generated) and may contribute, in principle, to ascertaining long-term energy supply security. in both china and india, however, vast opportunities exist for underground geologic waste storage, so that waste volume reduction is probably not a very important issue. arguments can be made for creating a reprocessing economy since it could enhance energy security but, as will be pointed out next, such reasoning does not appear very strong here. therefore, in decisions regarding whether to reprocess or not, economics probably plays a fundamental role in these countries. nuclear power in asia today, only eight developing countries (excluding those with economies under transition in central and eastern europe and the former soviet union) possess nuclear power or are in the process of building one or more nuclear reactors: argentina, brazil, china (including taiwan), india, iran, north korea, pakistan, and south africa (iaea 2002). of these, five are in asia. almost the entire current expansion of nuclear power capacity in developing countries today takes place in asia, with argentina being the only non-asian developing country that has currently a reactor under construction (south africa will probably build one or more again in the near future), and pakistan being the only asian developing country (of the ones that already possess some nuclear capacity) that currently has no additional power plant under construction (the other four asian developing countries with nuclear capacity or aspirations have at least one unit under construction). even seen from a global perspective, nearly all nuclear power expansion currently takes place in asia. today, the two countries in the world pursuing an expansion of their nuclear power capacities most actively (with the largest numbers of reactors under construction) are china (with three units under construction, totalling a net capacity of about 2.5 gwe (gigawatt-electric) and india (with eight units under construction, totalling a net capacity of over 2.5 gwe (iaea 2002). having tested a range of different reactor types, largely from canadian, french, russian, as well as domestic designs, china is now moving to standardization and self-reliance in design, manufacturing, construction, and operation. india has already occupied for some time a leading place among asian nations in indigenous design, development, construction, and operation of nuclear power reactors. because of their leading roles in the nuclear field in developing asia, their ambitious nuclear expansion plans, and their potential to become major exporters of nuclear 296 afr. j. environ. econ. manage. bindu 297 technologies, the decisions of china and india regarding nuclear energy will determine its development in asia and may have a sizeable effect on its evolution worldwide. fuel cycle, the currently proven domestic uranium reserves would probably be used up within a few decades (zhang 2001). china in 1997, electricity generation in china was 1163 twh (terawatt-hours), about three-quarters of it coming from coal-fired plants (iea 2000). over the coming two decades, it is expected to grow by about 5% per year, so that by 2020 electricity generation will amount to some 3691 twh. in 1997, electricity generation through the combustion of coal, oil, and natural gas amounted to 863 twh, 83 twh, and 7 twh, respectively. by 2020, these values are projected to increase to 2568 twh, 197 twh, and 149 twh, respectively. hydropower is estimated to generate around 622 twh in 2020 (196 twh today), while renewables remain negligible over the two decades. due to its large population and its heavy reliance on coal, china's contribution to global ghg emissions stands high. in 1997, its co2 emissions were 14% of the world total; by 2020, they are expected to climb to nearly 6.5 gt (gigatonnes)—roughly 18% of the world total. today, china has eight large nuclear reactors in operation, representing a net capacity of over 6 gwe. five of these started operating only during the past two years. within the next few years, three reactors currently under construction should be in operation too, taking the total available net nuclear power capacity to nearly 9 gwe. china's official plans for further expansion of nuclear capacity are ambitious and, until recently, reached as high as an installed capacity of 20 gwe by 2010 and 40 gwe by 2020.5 it is probable, however, that these official goals will not be met. still, china may well have installed a nuclear power capacity of about 20 gwe by 2020. nuclear energy's contribution to electricity generation in china is currently a little over 1%, and will most likely remain below 3% for decades. to realize and support the long-term expansion of its nuclear power programme, china plans to reprocess its spent nuclear fuel produced, and to recycle the resulting plutonium in mixed oxide, or mox, fuel for both lwrs and fbrs. china already possesses a small more or less operational civilian pilot reprocessing plant with a capacity of 50 tonnes of spent fuel per year, and has started the construction of an experimental fbr with a capacity of 25 mwe (megawatt-electric). decisions are pending on whether or not to build a large commercial reprocessing plant with an annual capacity of 800 tonnes of spent fuel as well as a 300-mwe fbr. energy security is a major reason for china's desire to operate a closed nuclear fuel cycle, rather than an open cycle in which spent fuel once discharged from the reactor is considered as waste and stored as such. indeed, under china's existing nuclear programme, based on a once-through india in 1997, electricity generation in india was 463 twh, about three-quarters of it coming from coal-fired plants (iea 2000). over the coming two decades, it is expected to grow by about 5% per year, so that by 2020 electricity generation will amount to some 1483 twh. in 1997, electricity generation through the combustion of coal, oil, and natural gas amounted to 339 twh, 12 twh, and 28 twh, respectively. by 2020, these values are projected to increase to 1008 twh, 32 twh, and 216 twh, respectively. hydropower is estimated to generate around 171 twh in 2020 (75 twh today), while the contribution of renewables will probably increase to the 1% level over the two decades. whereas india's population will soon surpass china's, india's level of ghg emissions will remain significantly lower over the decades to come. in 1997, its co2 emissions were 0.9 gt; by 2020, they are expected to climb to nearly 2.25 gt—a factor of three smaller than that of china. india currently possesses a rather large number of (small) reactors. today, it has 14 reactors in operation (with a cumulative capacity lower than the eight in china) representing a net capacity of around 2.5 gwe. by the second half of this decade, the eight reactors now under construction should all be in operation, taking the total available net nuclear power capacity to over 5 gwe. the indian government's official plans for further expansion of its nuclear power capacity are ambitious. like with other countries, the main rationale for india to embark upon an expansion of its nuclear power programme is its desire to create domestic energy security (iyengar 1999). it is realistic to assume that india will have installed a nuclear capacity of around 15 gwe by 2020. the current contribution of nuclear energy to electricity generation in india is close to 4%. with the domestic nuclear capacity increase as projected, this contribution could amount to 8% by 2020. like china, india has chosen the closed fuel cycle for realizing a long-term expansion of its nuclear power programme, and thus plans to reprocess the spent fuel generated by its nuclear power plants. india's programme is based on a three-stage plan, to eventually exploit its abundant domestic resources of thorium through the use of fbrs. in this plan, the first stage involves the construction of mainly phwrs (pressurized heavy water reactors) for electricity generation with the production of plutonium as a by-product. in the second stage, fbrs are built, to be fuelled with this plutonium and depleted uranium, to produce uranium-233 in their thorium-loaded blankets. in the third stage, fbrs are fuelled with thorium and the uranium-233 initially produced from the second stage. a small 14-mwth (megawatt-thermal) test fbr has been successfully operated for over a decade now, while a detailed design of a 500-mwe prototype fbr has been completed and a construction site approved. if current construction plans are realized, india's first large fbr could be commissioned by the end of this decade. as for china, a major reason for india to choose the closed nuclear fuel cycle is energy security. indeed, under india's first-stage, largely phwr nuclear power programme, domestic uranium reserves are expected to represent some 400 gwe-years worth of electricity, which would be consumed within a few decades under current nuclear power expansion plans (gopalakrishnan 2002).is reprocessing the right choice for asia? a recent study by the massachusetts institute of technology concludes that, over at least the next 50 years, the best choice to meet nuclear energy's challenges is the open, once-through fuel cycle (mit 2003). it judges that there are adequate uranium resources available at reasonable cost to support this choice under a global growth scenario of nuclear power. china and india have arrived at the critical point of deciding whether or not to develop large-scale reprocessing and breeder programmes. for both countries, energy security is one of the main arguments not to opt for the once-through nuclear fuel cycle that obviates the need to reprocess and recycle spent nuclear fuel. below, through at least six arguments, it is pointed out that energy security in china and india constitutes insufficient ground for justifying the elevated costs that the establishment of a closed nuclear fuel cycle would entail.6 first, advocates of a large nuclear energy programme including a plutonium recycling economy claim that it would reduce national dependence on foreign energy resources such as oil. this is true, since through nuclear energy one can decrease dependence on oil for electricity production. however, it is true only to a limited extent: nuclear energy and oil are today largely complementary energy resources, rather than substitutes. oil's largest application is currently in the domain of transport, for which nuclear energy is for the moment still unsuitable. only in the longer term could nuclear energy be used for the production of hydrogen, which is fit in principle for large-scale employment in the transport sector. second, in the two scenarios depicted for china and india, 3% and 8%, respectively, are possible (and probable) electricity shares for nuclear energy in 2020. (much higher shares by that time are deemed unlikely.) these shares correspond to a share in the national demand for energy (rather than for electricity) of a few percentage points at most. in view of the larger scheme of energy security, these numbers are too small to make any significant difference for the energy dependence of either of these countries. how the projected nuclear energy is produced for instance, whether it is through a reprocessing cycle or not matters little. third, if china's and india's energy infrastructures become more dependent on nuclear energy beyond the forthcoming two decades, while domestic fissile resources are rapidly used up, energy security could become a concern. however, a depletion of global uranium reserves is unlikely for a long time to come, due to the existence of large global reserves of uranium, the possibility of enlarging these by factors when exploration at higher costs is allowed, the likely presence of large and yet undiscovered uranium resources, and the availability in oceans of vast amounts of uranium, presumably recoverable at competitive prices. with a continued existence of well-established, commercial world markets for uranium, the supply of nuclear fuel does not seem in danger for many decades, if not centuries.7 fourth, several countries including south korea have shown that a large nuclear power programme can be easily realized, operated, and maintained without possession of large domestic uranium resources, extensive local enrichment facilities, and national nuclear fuel production. the reason is that the existing global market for uranium products is hardly subject to fluctuations in supply or price, and has so far not displayed the volatility that industries relying on the supply of petrol experience in global oil markets. fifth, uranium suppliers in the world are diverse, both geographically and politically, and are unlikely quite contrary to common practice in the global oil market to collude to raise prices dramatically or limit supplies substantially. also, in this respect, the differences are large in comparison to the behaviour of global oil markets, where even private consumers dependent on petrol for transportation regularly experience the fluctuations occurring in crude oil prices. sixth, even if domestic uranium supply security were to become a matter of concern at some point in the future, a strategic reserve of uranium fuel could be realized easily surely more easily than in the case of strategic oil reserves since uranium is inexpensive to buy, simple to handle, and easy to store. furthermore, the separation of plutonium increases the risk of illicit purchase by states or non-state/sub-national entities wishing to acquire nuclear weapons, as well as the risk of theft by terrorist groups attempting to develop nuclear fission devices. this implies increased costs and enhanced burden of safeguards and physical protection. the policies of china and india regarding reprocessing could significantly influence the attitude of the international community and the posture of powerful nuclear and economic actors in particular. indeed, the civil use of plutonium in these countries could serve as an encouragement or excuse for its use by other nations, especially when the latter have interests in using plutonium for military purposes. if china and india were to decide not to develop civilian reprocessing, a good example could be set for other countries in the region 298 afr. j. environ. econ. manage. bindu 299 contemplating the reprocessing and recycling of plutonium. also, it seems that china and india currently need to worry little about issues of public opinion (concerning safety, waste, and costs, for instance). the japanese case, however, may be indicative of how sensitive the matter of maintaining a reprocessing industry can become in these countries as well. the evolution of the reprocessing industry in japan will probably also influence its potential development in other asian countries, including china and india. with these arguments unfavourable to the development of a reprocessing industry an obvious question arises. why do some countries still choose this fuel cycle option, rather than considering spent fuel as waste once it leaves the nuclear reactor? indeed, china and india currently seem to continue to push for expanding reprocessing technology, and probably not merely for the aforementioned ‘standard reasons’— enhancing uranium resource efficiency and reducing radioactive waste volumes.8 in the way india's nuclear tests have been driven, partly by domestic policy and psychological factors, including the authority of the nuclear establishment (perhaps more than by geopolitical factors [perkovich 1999]), both in china and india the desire to possess the ability to reprocess may be associated with the virility of the nuclear research elite and thus with the prestige of the country. the chinese and indian push for reprocessing technology may partly be explained by elements like the domestic political need to show prowess and also the desire of scientists for continued access to research money and personal fame. clearly, one should look for arguments beyond economics to understand why countries like china and india push for reprocessing, but it goes beyond the scope of this paper to go into these matters more extensively. conclusion as summarized in the beginning of this paper, the fossil resource scarcity perception of the late 20th century was probably unjustified, that is, if one takes a long-term perspective. as the experience of western nations in the 1970s demonstrated, however, threats to energy security remain in terms of the possibility for the world community to need to face short-term energy disruptions. energy cooperation, increased energy efficiency, and 90-day strategic petroleum reserves were the western response to these disruptions in the late 1970s (manning 2000). in this, there maybe important lessons for asia. the us remains a resourceand energy-fuel-rich country, compared to most of the rest of the world, particularly east and south asia. china and india are generally richer in energy fuels than the rest of east and south asia, but for most of these fuels not as rich as the us (may 1998).thus, for asian countries, nuclear power is partially an insurance policy, the only long-term, internally sustainable energy resource now in sight that can generate electricity at affordable prices. holding back on nuclear power, including reprocessing, is therefore a more serious gamble for these countries than it is for the us. they are, therefore, unlikely to abstain from developing nuclear energy. a major challenge facing humankind during the 21st century will be to ascertain adequate, affordable, and reliable energy services in a sustainable manner. energy is a critical input for social and economic development. with energy use in many developing economies in asia still at a low level, with about 60% of the world's 2 billion people without access to modern energy services living in this part of the world, and with the global increase in energy demand concurrent with expected economic growth for a large part taking place in this region, it is important that the right (sustainable) energy choices are made (saha 2003). in developing countries, supply of energy should not become a constraint to their economic growth. security of supply does not seem to become a major issue for decades to come at least, if not longer, not in developing countries or elsewhere in the world. rather, the question is whether we can afford the current patterns of energy production and consumption to continue in the rapidly deteriorating health of our common environment. efforts to control climate change are becoming increasingly important, as well as the role that should be played herein by the implementation of carbonfree energy resources. for the time being, it seems safest to adopt a hedging strategy, in which all non-fossil energy technologies have a share in an energy mix as diversified as possible, including nuclear energy. still, however large an expansion of nuclear energy may once be realized, it will never contribute by more than a significant part to mitigating global warming, and cannot ever constitute the panacea to the challenge of climatic change. irrespective of what energy technology blueprint humankind finally deems most appropriate, and adopts, taking a transition path away from the current unsustainable patterns of energy use is one of the main challenges for both developed and developing countries. in attempting to establish sustainable energy systems worldwide, whether in the nuclear field or elsewhere, it is important not to simply impose the model in use in developed nations to countries in the developing world, given the latter's distinct (past) societal and economic evolution and different (current) social and cultural characteristics. china and india have a vast potential over the 2 ist century to affect regional and global energy markets, linked inextricably to an interdependent world energy sector (see, for the chinese case, ogiitcii 1998). meeting their energy needs in a secure, efficient, and sustainable manner remains one of the most significant challenges china and india face. the developments in the energy field in these two countries will not only determine (to a large extent) domestic economic prosperity and security 300 afr. j. environ. econ. manage. but also affect the global economy and environment. therefore, it is no longer useful to think purely in discrete european, american, or asian policy terms when analysing regional energy futures. in the increasingly interlinked world energy system, more integrated geostrategic policies and international cooperation are essential to sustain economic growth; to carry out multinational energy projects between china, india, and the industrialized world; and to protect the global environment. regional and international cooperation will remain important not only for harnessing and trading cleaner forms of energy, but also for addressing transboundary environmental concerns (datt, kacker, mehra, et al. 2002). nuclear energy is an option that probably should (and will) be pursued by china and india, as well as other asian countries, and perhaps by the developing world at large. nuclear energy can complement other options on the path to realizing clean and affordable energy production and consumption, and possesses intrinsic value in terms of the diversification of energy supply. it is important, however, that the right choices are made in the development of nuclear energy, if a decision is taken to include this option in national energy programmes. china and india, or other developing countries for that matter, do not need to pursue a reprocessing programme in the foreseeable future, based on the arguments made in this paper. it is cheaper to choose the option of direct disposal of spent fuel, rather than to opt for the alternative of reprocessing and recycling. substantial savings can be realized by going in for direct disposal. the resulting financial means, especially needed in developing countries, can be usefully employed in other domains, for example in the development of other clean energy options. the decision to eventually adopt a nuclear reprocessing economy or not should therefore be postponed, for at least a couple of decades to come, but probably longer. meanwhile, as new and more advanced nuclear technologies might emerge, the interim storage of spent nuclear fuel from a once-through cycle can be effectively and safely employed. since the expert discussion about reprocessing is likely to continue for years, countries like china and india could, for the time being, best employ the once-through nuclear cycle, until the reprocessing conundrum has been fully resolved and more technological clarity has been achieved on the nuclear technology to be employed in the future. references alvarez r, beyea j (2003). reducing the hazards from stored spent power-reactor fuel in the united states science and global security11(1): 1-51 bruggink jjc, c (2002). the role of nuclear energy in establishing sustainable energy paths international journal of global energy issues18(2, 3, 4): 151-180 bunn m (2003). the economics of reprocessing vs direct disposal of spent nuclear fuel: managing the atom project cambridge, usa: belfer center for science and international affairs and kennedy school of government, harvard university. datt d ( 2002).sustainable energy: trends and perspectives for asiapacific and asian journal of energy12(2): 129-149 ec, iepe (institute of energy policy and economics), bfp (belgian federal planning bureau), ipts (institute for prospective technological studies).(2003) world energy, technology and climate policy outlook 2030brussels: european commission gopalakrishnan a (2002). evolution of the indian nuclear power programmeannual review of energy and the environment27: 369395 iaea (international atomic energy agency) .(2002)nuclear power status around the worldiaea bulletin iea (2000).world energy outlook paris: international energy agency, organisation for economic co-operation and development iea (2002).energy and poverty (special issue in the world energy outlook (2002)paris: international energy agency, organisation for economic co-operation and development iiasa (international institute for applied systems analysis) and wec (world energy council) . 1998global energy perspectives, edited by nakicenovic n, griibler a, mcdonald a cambridge, uk: cambridge university press ipcc (intergovernmental panel on climate change) . 2001climate change 2001: the scientific basis[contribution of working group i to the third assessment report of the ipcc, edited by j t houghton, y ding, d j griggs, m noguer, p van der linden, x dai, k maskell, c i johnson]cambridge, uk: cambridge university press iyengar pk (1999). problems and prospects for nuclear power in india in nuclear energy: promise or peril?, edited by van der zwaan b c c, hill c, mechelynck a l, ripka g singapore: world scientific. 288 pp. manning ra (2000). the asian energy predicamentsurvival perkovich g (1999). india's nuclear bomb: the impact on global proliferationberkeley: university of california press. 597 pp. rabl a (2001).the importance of external costs for the competitiveness of renewable energiesinternational journal of global energy issues15(1/2) rogner hh (1997).an assessment of world hydrocarbon resourcesannual review of energy and the environment footnotes 1 all energy consumption patterns from 2000 to 2075 are assumed to increase linearly. 2 such a carbon emission profile would preclude reaching over a doubling of the co2 concentration in the atmosphere. a doubling of this concentration corresponds to an increase of the average atmospheric temperature on earth by around 1.5-4.5 °c (referred to as the ‘climate sensitivity’; see ipcc 2001). 3 the data on nuclear energy in rabl (2001) comes from the french nuclear power programme. this does not necessarily correspond with that from nuclear programmes in other countries because, for example, safety measures may not have been implemented as strictly in china as they have been in france. 4 also, if in some country or by some terrorist group, civil separated plutonium will one day be diverted into an atomic explosive, this may well provoke military and/or anti-terrorist expenditures the world over, and is also likely to adversely affect civil reprocessing programmes in all countries practicing the closed fuel cycle. these consequences are not accounted for in external cost calculations. similar arguments can be made regarding the possibility to construct radiological devices (dirty bombs) from spent nuclear fuel material. bindu 301 5 meanwhile, it seems that this impressive aim is currently being adjusted downwards. 7 admittedly, arguments three through six hold less for india than they do for china, given the embargo and isolation it has experienced from most western and other nuclear suppliers since its underground nuclear tests in 1974. still, if after further exploration of potential land and ocean resources, uranium proves to be insufficiently abundant domestically, uranium could in principle be imported from countries that are not members of the nuclear suppliers group (for instance nigeria in africa). also, at some point, a solution may be found for the current political international impasse regarding india's nuclear programme.8by engaging on the reprocessing path, china and india are apparently prepared to spend more for those other reasons; how much more has been calculated by bunn, fetter, holdren, et al. (2003). in ternationa l scholars journa ls african journal of environmental economics and management issn 2375-0707 vol. 7 (7), pp. 001-010, july, 2019. available online at www.internationalscholarsjournals.org © international scholars journals author(s) retain the copyright of this article. full length research paper effect of biotic and abiotic factors on composition and foraging intensity of subterranean termites swidiq mugerwa1,2*, moses nyangito1, denis mpairwe3 and john nderitu1 1 department of larmat, p. o. box 30197, university of nairobi, kenya. 2 national livestock resources research institute, p. o. box 96, tororo, uganda. 3 department of animal science, makerere university, p. o. box 7062, kampala, uganda. accepted 07 march, 2019 elucidating the influence of ecological factors on composition and foraging intensity of subterranean termites is critical in development of sustainable termite management strategies. our aim was therefore to analyze the effect of selected biotic and abiotic factors on composition and foraging intensity of termites. we used principal component and canonical correspondence analysis to select appropriate factors and to model relationships respectively. macrotermes species occurred in sites where the quantity of litter was generally above the mean. however, macrotermes herus (rambur) and macrotermes spp.4 occurred in sites where the litter quantity was below the mean. trinervitermes oeconomous (tragardh) and odontoremes spp.1 were noted to occur in the direction of increasing quantity of biomass. generally, most species occurred in sites where soil ph was above or slightly below the mean (4.8). majority of the species were also noted to occur in sites where bulk density was below or slightly above the mean (1.55 g/cm 3 ). highest bait consumption (95%) occurred within a range of 55 to 60% basal cover beyond which the amount of bait consumed reduced. litter and biomass quantity, ph and bulk density were noted as the most influential environmental variables determining composition of termites while basal cover was the major determinant of foraging intensity. key words: rangelands, macrotermes, rangelands, vegetation, litter, biomass, basal-cover. introduction determinants of the structure and activity of subterranean termites at a large-scale are well known: climate, soil type, land use management practices and landscape structure are among the most influential factors (dauber et al., 2003, 2005). at smaller scales, however, there is less agreement about the biotic and abiotic factors that drive variability in composition and activity of macro-fauna including subterranean termites (lavelle and spain, 2001). mitchell (2002) reported that the amount of available litter (both leaf and wood) was a major determinant of foraging intensity on vegetation by generalist feeders such as members of the genera macrotermes and odontotermes. he further noted that in sites with limited litter resources, termites resorted to *corresponding author. e-mail: swidiqk@yahoo.com. tel: +256782660295. standing biomass and consumed more than 60% of the standing crop. mathieu et al. (2009) and attignon et al. (2005) also reported that high encounters of macrotermes species (mainly fungus growers) were associated with sites with high litter biomass and low soil water content. curry (1994) observed the survival and activity of macro-fauna on various sites to be influenced by the micro-climate and the quality of food in the various sites. micro-climate is very important since the body temperature of soil macro-fauna varies with external temperature (thermo-conformers) and the range tolerated by many species is narrow (geiger and aron, 2003). geiger and aron (2003) further noted that soil macro-fauna including subterranean termites need to maintain body water content within fairly narrow limits, which creates a dependence on soil water. this implied that the structure, survival and activity of subterranean termites would be enhanced on sites with acceptable levels of soil water content. martison et al. (2008) reported that soil macro-fauna organisms are also sensitive to the nutrient content of their food because they need to maintain their internal chemical concentrations and the balance between the different nutrients of their body within a strict range. to this effect, elements of food quality such as phosphorus (mcglynn and salina, 2007), nitrogen (waren and zou, 2002) and ca 2+ (reich et al., 2005) content, can become a limiting factor to composition, survival and activity including foraging intensity of subterranean termites. mathieu et al. (2009) also reported that the composition and activity of subterranean termites was influenced by presence of basal vegetation with more diversity in areas covered with grass tufts than on bare ground. in the rangelands of nakasongola district in uganda, vegetation is typically dominated by large herb turfs of the genera hyparrhenia and brachiaria, which clearly alternate with bare ground and shrubs. the vegetation cover is highly variable, from dense to completely bare ground leading to heterogeneous habitats with varying biotic and abiotic factors. the composition and foraging intensity of subterranean termites seem to be driven by the site-specific biotic and abiotic properties occurring on the different vegetation patches. on some patches, the termite assemblage structure is dominated by macrotermes species while cubitermes species dominate on other patches. further, the population and foraging intensity of subterranean termites also varies from one site to another with most of the patches experiencing extra-ordinarily high foraging intensity of termites resulting into denudation of basal vegetation, forage scarcity and eventually poor livestock performance. typical foraging is characterized by subterranean galleries leading to surface foraging holes from which termites emerge to remove dead grass and grass litter under cover of constructed soil sheeting. termite foraging is particularly obvious during the dry season when bare rangeland can have up to 55 foraging holes per m 2 (cowie and wood, 1989). during such times the combined grazing effect of livestock and termites is to virtually denude considerable tracts of grassland, exposing soils to erosion by both wind and water (mitchell, 2000). recognizing the impact of biotic and abiotic factors on composition and foraging intensity of subterranean termites in savanna ecosystems, development of sustainable termite management strategies in the termite infested rangelands of nakasongola requires adequate knowledge of the site-specific influence of biotic and abiotic factors on the composition and foraging intensity of termites. this will ensure that management of rangeland ecosystems aim at provision of the necessary ecological resources and conditions to overcome the detrimental impact of subterranean termites on rangeland vegetation. however, such information is still poorly documented. in particular, we lack information on the biotic and abiotic factors that enhance foraging intensity of subterranean termites as well as the ecological factors that are responsible for the variation in termite assemblage structure across various rangeland sites. our aim was thus to analyze the effect of biotic (tree canopy cover, number of woody species, biomass and basal cover) and abiotic (soil moisture, soil temperature, bulk density, soil ph, litter quantity and soil organic matter) on the composition and foraging intensity of subterranean termites on the grazing lands in semi-arid nakasongola. we examined two hypotheses: (1) the composition of subterranean termites will not vary among sites with different biotic and abiotic factors and (2) the percentage of baits consumed by subterranean termites (foraging intensity) will not vary among sites with different biotic and abiotic factors. materials and methods description of the study area the study was conducted on one savanna site, locally referred to as kamukama ranch. the site is located in nakasongola district (55°140’ n, 32° 50’ e) of uganda (figure 1). the mean daily maximum temperature in the district is 30°c. rainfall range between 500 to 1000 mm per annum and there are two rain seasons. the main rain season occurs from march-april to junejuly while the second rain season follows from august to octobernovember. a long dry season occurs from december to february while a short spell comes around july-august. the vegetation on the study site mainly comprised of three vegetation cover types depending on the extent of anthropogenic activities/disturbance on specific ranch sites. the three vegetation cover types included dense vegetation cover (>50% basal cover), sparse vegetation cover (25 to 50% basal cover) and bare ground (<25% basal cover). the vegetation cover types are majorly a product of intricate interactions between climatic conditions and anthropogenic activities such as overgrazing, indiscriminate tree cutting and bush burning among others. the dense vegetation cover category on the study site mainly comprised of tarrena graveolens and acacia species forming 62 and 3% of the total woody canopy cover and woody density of 575, 125 trees ha -1 respectively. the herbaceous vegetation was dominated by brachiaria species contributing 88% of the basal cover. the sparse vegetation cover category was dominated by cynodon dactylon and loudetia kagerensis forming 67 and 12% of the species cover. scattered woody species on the sparse vegetation cover were also dominated by t. graveolens, forming 34% of the woody canopy cover. the bare ground category mainly comprised of highly scattered harrisonia abyssinica and t. graveolens forming less than 0.5% canopy cover each. the number of mounds ranged from 33 to 525 with an average of 227 mounds ha -1 . the soil is generally moderately acidic with the ph ranging between 4 and 5.5. the soil organic matter (%), nitrogen (%), available phosphorus (ppm) and potassium (cmoles/kg) were 1.3, 0.1, 4.2 and 0.23 respectively. the soils generally belonged to the soil textural class of sandy loam. sampling and classification of termite species the standardized sampling protocol developed by jones and eggleton (2000) was used to sample termites. the protocol figure 1. map of uganda showing the location of nakasongola district. involved lying belt transects of 100 m length by 2 m width, divided into 20 contiguous sections of 5 × 2 m. each section was sampled by two trained people for 30 min (a total of one hour of sampling per section). in each section the following microhabitats were searched: 12 samples of surface soil (each about 12 × 12 cm, to 10 cm depth); accumulations of litter and humus at the base of woody plants, the inside of tree stumps, dead logs, branches and twigs; the soil within and beneath very rotten logs; subterranean nests, mounds, carton sheeting and run ways on vegetation, and arboreal nests up to a height of 2 m above ground level. workers and soldiers (if present) from every termite population encountered were sampled and the samples were preserved in 80% ethanol. the belt transect provides a measure of relative abundance of termites based on the number of encounters with each species in the transect. an encounter was defined as the presence of a species in one section. the vegetation of the study site was blocked in to three vegetation categories based on the quantity of vegetation covering the ground. the three categories included dense (> 50% basal cover), sparse (25 to 50% basal cover) and bare ground (< 25% basal cover). two replicate belt transects were run in each of the three vegetation categories between december and january, the period when termite activity and subsequent destruction of vegetation by termites is reported to be severe (nakasongola district state of environmental report, 2004). sampling for termite species was conducted in 2010 and 2011. taxonomic identification for collected samples was done at family, sub-family, genus using standard determination keys by webb (1961) and where possible to species’ level using existing records of termite species in nakasongola rangelands by sekamatte (2001). sampling for biotic and abiotic variables several environmental variables were recorded between 2010 and 2011 to assess their influence on termite assemblages. measurements were made during the main rainy (march-april/junejuly) and the dry season (december to february). the soil water content (percent gh2og -1 oven-dry soil) was measured from four surface soil samples (2 to 10 cm) taken from sections 3, 8, 13 and 18 of every belt transect (attignon et al., 2005). the same samples were analyzed for bulk density (g/cm 3 ), soil ph and soil organic matter (%) according to methods described by anderson and ingram (1993). soil temperature (°c) was determined by randomly inserting thermometers in the soil at any two locations in each of the four sections (3, 8, 13 and 18). the same sections were also sampled for herbaceous biomass quantity and litter quantity (both wood and leaf litter). the number of functional/live termite mounds per section was also quantified. because the size of the sections was no sufficient to quantify canopy cover (kent and coker, 1992), three plots of 50 by 50 m were established in every vegetation category to enable estimation of tree/woody species density and woody canopy cover. herbaceous biomass quantity was estimated by randomly placing two quadrats (1 m 2 ) in each of the four sections. the above ground herbaceous vegetation within each 1 m 2 quadrat was cut at ground level, put in plastic bags and weighed as described by l.’tmannetje (1978). to quantify the amount of litter table 1. cumulative variability explained by five factors and factor loadings of vegetation variables. vegetation variables f1 f2 f3 f4 f5 eigenvalue 3.287 0.852 0.457 0.256 0.148 variability (%) 65.75 17.03 9.14 5.12 2.96 cummulative (%) 65.75 82.78 91.92 97.04 100 factor loadings biomass quantity 0.88 -0.35 -0.16 0.04 0.29 litter quantity 0.84 -0.03 0.47 -0.28 -0.01 no. of woody species 0.61 0.73 -0.28 -0.15 0.03 woody canopy cover 0.87 0.24 0.2 0.39 -0.06 basal cover 0.84 -0.38 -0.30 -0.06 -0.25 available, two quadrats (1 m 2 ) were placed randomly in each of the four sections and all available dead plant material enclosed by the quadrat was collected, oven dried and weighed. the woody canopy cover and the number of woody species for each plot were estimated according to methods described by kent and coker (1992). estimation of foraging intensity the effect of biotic and abiotic factors on foraging intensity was estimated using dried hyparrhenia rufa grass baits as described by and nash et al. (1999) and pearce (1997). we selected h. rufa because the grass is reported to be among the most susceptible grass species in the area and is thus readily consumed by subterranean termites. four litter bags (18 ×15 cm) of mesh size 4 mm, containing the same quantity of dried h. rufa grass were randomly placed on the surface in each of the four sections (3, 8, 13 and 18) of every belt transect. the bags were surrounded by three big stones to hold them in position or to prevent livestock and run-off from displacing them. the bags were removed after two weeks and were replaced twice in every season. after collection of baits, gallery carton and soil were carefully removed from all baits. the cleaned baits were oven dried at 60°c for 72 to 96 h and the dry weight recorded. the percentage of bait consumed (pc) was estimated as pc = ((wi-wf )/ wi)*100 were wi is initial weight of grass bait before consumption by termites, wf is final weight after consumption by termites. the percentage of bait consumed by termites was used as a proxy for determination of foraging intensity. data analysis in order to establish the effect of environmental variables on composition of termite species, we subjected the biotic and abiotic factors to principal component analysis (pca) to obtain noncorrelated factors which were linear combinations of the initial variables (jolliffe, 2002). based on the eigenvalues and the variability explained by each factor, a few factors were selected. the vegetation and soil variables were analyzed separately in pca and the selected variables for vegetation and soil were subjected to canonical correspondence analysis (cca) in xlstat (2011). we opted for factors that accounted for at least 90% of the cumulative variability. pca (pearson type; correlation biplot) of vegetation variables led to selection of three factors which accounted for 92% of the cumulative variability. pca (pearson type; correlation biplot) of soil variables led to selection of four factors that accounted for 98% of the cumulative variability. the selected factors were then used to model relationships in cca (ter braak and verdonschot, 1995) by extracting synthetic environmental gradients from the ecological data set as well as to develop ordination biplots. in order to establish the effect of environmental variables on foraging intensity (percentage of baits consumed), we also subjected the biotic and abiotic factors to (pca) to obtain non-correlated factors which were linear combinations of the initial variables (jolliffe, 2002). based on the eigenvalues and the variability explained by each factor, a few factors were selected. the selected factors were subjected to non-linear regression to clearly model the relationship. results effect of environmental variables on composition of subterranean termites principal component analysis on vegetation variables indicated that the first three factors explained 92% of the cumulative variability (table 1). biomass quantity (bq), number of wood species (nws) and litter quantity (lq) were strongly correlated with factors one (r = 0.88), two (r = 0.73) and three (r = 0.5) respectively. biomass quantity, number of wood species and litter quantity also loaded highest on f1, f2 and f3 respectively. the factor loading for bq, lq and nws was 0.88, 0.73 and 0.47 on f1, f2 and f3 respectively. the three vegetation variables were thus selected for inclusion in canonical correspondence analysis to establish the effect of the factors on composition of termite species. on the other hand, principal component analysis on soil variables showed that the first four factors explained 98% of the cumulative variability (table 2). soil water content (swc), ph, bulk density (bd) and soil organic matter (som) were highly correlated with factors one (r = 0.86), two (r = 0.69), three (r = 0.69) and four (0.38) respectively. swc, ph, bd and som also loaded highest on f1, f2, f3 and f4 respectively. the factor loading for swc, ph, bd and som was 0.86, 0.69, 0.69 and 0.38 on f1, f2, f3 and f4 table 2. cumulative variability explained by five factors and factor loadings of soil variables. soil variables f1 f2 f3 f4 f5 eigenvalue 2.692 1.001 0.763 0.443 0.100 variability (%) 53.85 20.029 15.255 8.861 2.005 cummulative (%) 53.85 73.879 89.134 97.995 100.00 factor loadings soil temperature -0.78 0.31 0.39 0.34 0.15 soil water content 0.86 -0.25 -0.30 0.25 0.20 ph 0.63 0.69 0.13 -0.33 0.10 soil organic matter 0.83 0.35 0.16 0.38 -0.16 bulk density 0.51 -0.5 0.69 -0.11 0.02 respectively. four soil variables were selected for inclusion in canonical correspondence analysis to establish the effect of the variables on composition of termite species. since the origin (0, 0) of any environmental variable on the ordination biplot represents the mean of that particular variable, macrotermes species are generally considered to have occurred in sites where the quantity of litter was above the mean (figure 2). however, macrotermes herus and macrotermes spp.4 occurred in sites where litter quantity was below the mean (778 kgha 1 ). pseudocanthotermes species, cubitermes spp.3 and 1 also occurred in sites where the amount of litter was lower than the average litter quantity. by projecting species points on the line of litter quantity, it was indicated that macrotermes spp.2 had the highest weighted average for litter quantity while pseudocanthotermes species seemed to occur in sites where the litter quantity was extremely below the average. it was further noted that although macrotermes species occurred in sites where amount of litter was above the mean, the species disappeared in sites where litter quantity was greatly above the mean. trinervitermes oeconomous and odontoremes species were noted to occur in the direction of increasing quantity of biomass and once the line of biomass quantity is extended beyond the displayed maximum point, t. oeconomous and odontoremes spp.1 would have the highest weighted average than all the displayed species. the point for number of woody species (nws) occurred at the origin of both litter quantity and biomass quantity and was associated with species which occurred in sites where the quantity of litter and biomass was around the mean. projection of soil variables on the axes showed that ph was more correlated with axis 1 while bd was more correlated with axis 2 than other variables (figure 3). generally, most species occurred in sites where soil ph was above or slightly below the mean (4.8). it was noted that the majority of macrotermes species and odontotermes species occurred in sites where the ph was slightly above or below the mean. the species (macrotermes and odontotermes) were noted to disappear in the direction of increasing ph. most of the species occurred in sites where bulk density was below and slightly above the mean (1.55 g/cm 3 ). the diversity of species was noted to decline in the direction of increasing bulk density. it was also noted that macrotermes spp.1, odontotermes spp.1, microtermes species and pseudocanthotermes species were the only members of the sub-family macrotermitinae that occurred in sites were bulk density was below average. most members of the sub-family macrotermitinae occurred in sites where bulk density was slightly above the mean and finally disappeared in sites with high bulk density. only ancistrotermes species and cubitermes spp.3 were noted to occur in sites with high values of bulk density. effect of environmental variables on foraging intensity of subterranean termites principal component analysis on environmental variables led to selection of four principal components (factors) that contributed 96% of the cumulative variability (table 3). based on the loading of various environmental variables on the selected factors, four variables were selected to explain the effect of the variables on foraging intensity of subterranean termites. the selected variables included basal cover (bc), number of mounds (nm), litter quantity (lq) and woody canopy cover (wcc). bc and nm loaded highest on f1 (0.99) and f2 (0.799) while wcc and lq loaded highest on f3 (0.641) and f4 (0.45) respectively. pearson correlation tests showed significant (p>0.05) correlations between bc and the other three selected variables. bc was positively correlated with nm (r=0.65, p=0.001), wwc (r=0.7, p<0.0001) and lq (r=0.83, p<0.0001). based on results from principal component analysis and pearson correlation tests, only one variable (bc) was selected to explain the variability in foraging intensity since the remaining variables were 2 1.5 1 0.5 % ) f2 (4 2. 37 0 -0.5 -1 microtermes species ancistrotermes species procubitermes lq species macrotermes spp2 macrotermes spp3 m. bellicosus nws macrotermes spp1 odontotermes spp2 cubitermes spp3 macrotermes spp4 cubitermes spp2 cubitermes spp1 bp macrotermes herus pseudocanthotermes spp t. oeconomous odontotermes spp1 -1.5 -3 -2.5 -2 -1.5 -1 -0.5 0 0.5 1 1.5 2 2.5 3 3.5 f1 (54.04 %) figure 2. ordination biplot based on canonical correspondence analysis of species/vegetation matrixes displaying 17.6% the inertia (= weighted variance) in species’ abundances and 96% of variance in weighted averages with respect to the vegetation variables. the eigenvalues of axis 1 (horizontally) and axis 2 (vertically) are 0.29 and 0.23 respectively. the eigenvalue of axis 3 (not displayed) is 0.019. positively correlated with the selected variable. results from nonlinear regression of percentage of bait consumed with basal cover indicated that highest consumption of baits (95%) occurred within a range of 55 to 60% basal cover (figure 4). below this range, bait consumption was noted to decrease up to 0%. beyond the same range, bait consumption was observed to decline but did not reach 0%. reduction in basal cover from 100 to 80% was noted to double bait consumption from 38 to 76% while basal cover reduction from 80 to 60% caused 24% increase in bait consumption. discussion effect of environmental variables on composition of subterranean termites although macrotermes species are regarded as generalist feeders (donovan et al., 2001; wood, 1991) that forage on various organic resources such as grass, wood, dung and plant debris, mitcheal (2002) noted that the species are predominantly litter feeders and their diversity and density would increase in areas with adequate availability of food (litter) resources. okwakol and sekamatte (2007) also noted that increased availability of litter due to clearance of trees led to an increase in density and diversity of litter feeding species, particularly macrotermes species in forest ecosystems in uganda. these observations agree with the observed trend in the current study where more species occurred in sites where litter quantity was above the mean. the occurrence of more macrotermes species in areas with adequate litter resources implied that availability of food resources was one of the key factors influencing the spatial variability in diversity and density of the species. however, the absence of the same species in sites where the lq was highest (greatly above the mean) could be f 2 ( 2 4 .1 1 % ) 2 pseudocanthotermes trinervitermes species species sm procubitermes 1 species om cubitermes spp2 m.spp1 o.spp1 cubitermes spp1 0 microtermes species odontotermes spp2 m. herus m.billicosus ph m.spp4 macrotermes spp2 -1 macrotemes spp3 ancistrotermes species bd -2 -3 cubitermes spp3 -4 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 f1 (46.72%) figure 3. ordination biplot based on canonical correspondence analysis of species/soil matrixes displaying 24% the inertia (= weighted variance) in species’ abundances and 71% of variance in weighted averages with respect to the soil variables. the eigenvalues of axis 1 (horizontally) and axis 2 (vertically) are 0.34 and 0.18 respectively. the eigenvalue of axis 3 and 4 (not displayed) are 0.12 and 0.09 respectively. table 3. cumulative variability explained by ten factors and factor loadings of environmental variables. environmental variables f1 f2 f3 f4 f5 f6 f7 f8 f9 f10 eigenvalue 7.42 1.23 0.67 0.31 0.21 0.13 0.03 0.01 0.002 0.001 variability (%) 74.2 12.3 6.6 3.1 2.1 1.3 0.3 0.1 0.02 0.01 cummulative (%) 74.2 86.5 93.1 96.2 98.3 99.6 99.86 99.97 99.99 100.0 factor loadings bq 0.941 0.061 -0.04 -0.11 0.109 0.286 0.053 0.016 0.002 -0.002 lq 0.85 -0.10 -0.23 0.45 0.055 -0.04 0.054 -0.003 0.000 -0.003 bc 0.992 0.091 -0.013 -0.002 -0.009 -0.032 -0.071 0.027 0.034 -0.010 nws 0.692 -0.607 0.243 -0.163 0.221 -0.123 0.039 -0.016 0.001 -0.005 wcc 0.723 -0.048 0.641 0.123 -0.219 0.029 0.017 0.010 -0.002 0.002 nm 0.583 0.791 0.031 -0.124 -0.015 -0.113 0.071 -0.030 0.005 -0.003 st -0.991 0.004 0.011 -0.028 -0.008 -0.068 0.075 0.081 0.005 -0.004 sm 0.986 0.090 -0.059 -0.034 0.093 -0.073 -0.015 0.035 -0.001 0.025 som 0.980 0.167 -0.060 -0.050 0.005 -0.048 -0.045 0.032 -0.033 -0.013 bd -0.754 0.414 0.354 0.169 0.306 0.029 -0.036 0.005 -0.001 -0.0 bq: biomass quantity, lq: litter quantity, bc: basal cover, nws number of woody species, wcc: woody canopy cover, nm: number of mounds, st: soil temperature, sm: soil moisture, som: soil organic matter, bd: bulk density. 100 90 80 c o n s u m e d 70 60 % consumed= 0.23+3.4*bc-3.05e-02*bc^2, r 2 = 0.83 50 b a it o f 40 % 30 20 10 0 0 10 20 30 40 50 60 70 80 90 100 basal cover (%) figure 4. nonlinear regression curve of basal cover and percentage of bait consumed. partly attributed to presence high densities of predators particularly predator ants that nest in litter. cubitermes species were noted to occur in sites where litter quantity was below the mean and this was partly attributed to the fact that the species are generally soil feeders (donovan et al., 2001) and can survive in areas with limited litter resources. trinervitermes oeconomous is a specialized grass feeder while odontotermes species have also been reported to consume significant amounts of herbaceous vegetation. this could be a possible explanation of the occurrence of the species in sites with high biomass production as the sites could avail the species with adequate feed resources. the significant positive correlation between ph and soil organic matter meant that sites with low soil ph had low soil organic matter which limited availability of nutrients for plant establishment and this could have limited availability of adequate food resources for survival and activity of most termite species. further, limited availability of soil organic matter meant that termites lacked the necessary nutrients to sustain their nutrition requirements. in this regard, martison et al. (2008) also reported that soil macro-fauna organisms are sensitive to the nutrient content of their food because they need to maintain their internal chemical concentrations and the balance between the different nutrients of their body within a strict range. to this effect, elements of food quality such as phosphorus (mcglynn and salina, 2007), nitrogen (waren and zou, 2002) and ca 2+ (reich et al., 2005) content, can become a limiting factor to composition, survival and activity including foraging intensity of subterranean termites. trampling by grazing animals causes soil compaction, reduction of permeability, organic carbon, and nutrients, and restrict plant growth (yates et al., 2000), reducing the input of organic matter into the soil and resources available to decomposers (chapin et al.,2002). eventually, the soil faunal diversity and density is likely to decrease in highly compacted areas. this explains the limited occurrence of termites in sites where the bulk density was greatly above the mean. the results have also indicated that members of the sub-family macrotermitinae, the dominant sub-family on grazing lands in semi-arid nakasongola, are sensitive to changes in bulk density and their activity and survival could be influenced by interventions that alter soil bulk density. since the species are associated with destruction of herbaceous vegetation in termite infested rangelands, management decisions aimed at reducing bulk density below the average value reported in the current study would possibly check their activity and eventually reduce their destructive effect on herbaceous vegetation. however, more scientific investigations are necessary to determine the most appropriate level of bulk density that ensures optimum biomass production for livestock nutrition but also mitigating the destructive effect of subterranean termites on vegetation. effect of environmental variables on foraging intensity of subterranean termite the significant positive correlation between basal cover and litter quantity meant that sites with high proportion of basal cover also had high quantities of litter. this implied that such sites had adequate food resources for both generalist termite feeders (members of sub-family macrotermitinae) and the specialized grass feeders (trinervitermes species). this could have resulted to the low response of termites to supplementary food sources in form of baits. the observed increase in bait consumption due to a decline in basal cover from 100% implied that feed availability was limiting and hence termites responded greatly to provision of additional/alternative food resources in form of baits. however, this trend occurred up to a certain point (55 to 60%) beyond which the proportion of bait consumed started to decline. as basal cover continues to decline, the land becomes bare leading to high rates of run-off, erosion, and eventually loss of soil organic matter. the bare surfaces are also associated with low soil water content due to reduced water infiltration and high soil temperature which limit the survival and populations of termites. eventually, the consumption of baits decreased as the land became bare not because the termites had plenty of food resources to forage on but because there were limited populations of termites to feed on the baits. the findings of the study suggested that availability of adequate food resources (litter and standing biomass) is critical in determining the foraging intensity of subterranean termites on organic resources. this implied that the foraging intensity of subterranean termites on alternative food resources would be high in sites with inadequate conventional food resources. no wonder, foraging intensity of termite on rangeland vegetation was reported to be highest on degraded patches with sparse vegetation cover and limited availability plant biomass and litter. the results of the study are consistent with findings of wood (1991) who noted that destructive effect of termites on rangeland vegetation was more severe on overgrazed land with limited net primary productivity and litter availability. conclusion in sum, the composition and foraging intensity of subterranean termites on grazing lands in semi-arid nakasongola was influenced by certain biotic and abiotic factors. litter and biomass quantity were noted as the most influential vegetation variables while soil ph and bulk density were noted as the most influential soil variables driving the variability in composition of subterranean termites. increasing litter quantity was noted to favor occurrence of macrotermes species to a certain level beyond which the species disappear. recognizing the fact that macrotermes species are reported as the major pests to vegetation on grazing lands in nakasongola, interventions that enhance accumulation of litter beyond the level for their optimum occurrence would reduce their destructive effect on vegetation. it was further observed that basal cover was the main determinant of foraging intensity of termites on dried h. rufa grass. the foraging intensity was noted to decrease with increase in basal cover suggesting that management decisions for rangeland vegetation need to focus on maintaining adequate basal cover if termite damage on vegetation is to be reduced. the termite species in the nakasongola ecosystem are predominantly litter feeders but can forage on herbaceous biomass in absence of adequate litter sources to cause significant denudation of rangeland vegetation. ecologically sustainable management of these species requires rangeland managers to sustain the ecological integrity of termite infested ecosystems through undertaking appropriate ecosystem management techniques that maintain an ecological equilibrium between termites and other ecosystem components to prevent competition for ecological resources. anthropogenic activities that degrade ecosystems such as overgrazing and indiscriminate tree cutting need to be checked. it is also important to sustain adequate availability of organic materials (such as litter) and herbaceous vegetation cover to avail termites with adequate food resources to prevent them from damaging vegetation. however, further research in the field need to focus on development of thresholds for litter (both quantity and quality) and amount of vegetation cover beyond which termites become destructive. acknowledgement the study was partially funded by the regional universities forum for capacity building in agriculture (ruforum) and the national livestock resources research institute (nalirri) in uganda. references anderson jm, ingram jsi (1993). tsbf: a handbook of methods of analysis. cab int., p. 39. attignon se, lachat t, sinsin b, nagel p, peveling r (2005). termite assemblages in west-african semi-deciduous forest and teak plantations. agric. ecosyst. environ., 110: 318-326. chapin fsiii, matson pa, mooney h (2002). principals of terrestrial ecosystem ecology. springer-verlag, new york. cowie rh, wood tg (1989). termite damage to crops, forestry and rangeland in ethiopia. sociobiol., 15: 139-153. curry jp (1994). glassland invertebrates, ecology, influence of soil fertility and effects on plant growth. chapman and hall, london, uk, pp. 437-146. dauber j, hirsch m, simmering d, waldhardt r, otte a, wolters v (2003). landscape structure as an indicator of biodiversity: matrix effects on species richness. agric. ecosys. environ., 98: 321-329. dauber j, purtauf t, allspach a, frisch j, voigtlander k, wolters v (2005). local vs landscape controls on diversity: a test using surfacedwelling soil macro-invertebrates of different mobility. global ecol. biogeogr., 14: 213-221. donovan se, eggleton np, bignell de (2001). gut content analysis and a new feeding group classification of termites. ecol. entomol., 26: 356-366. geiger r, aron rh (2003). the climate near the ground. rowman & litlefield publishers, lanham, usa, 600 p. jolliffe it (2002). principal component analysis, second edition. springer, new york. jones dj, eggleton p (2000). sampling termite assemblages in tropical forests: testing a rapid biodiversity assessment protocol. j. appl. ecol., 37: 191-203. kent m, coker p (1992). vegetation description and analysis. a practical approach. elhaven press, london, uk. lavelle p, spain av (2001). soil ecology. kluwer scientific publications, amsterdam, 654 p. l.‘t mannetje (1978). measurement of grassland vegetation and animal production. csiro division of tropical agronomy. cunningham laboratory. brisbane, queensland, australia. martinson hm, schneider k, gilbert j, hines je, hamback ra, fagan wf (2008). detritivory: stoichiometry of a neglected trophic level. ecol. res., 23: 487-491. mathieu j, grimaldi m, jouquet p, rouland c, lavelle p, desjardins t, rosi j-p (2009). spatial patterns of grasses influence soil macrofauna biodiversity in amonia pastures. soil biol. biochem., 41: 586-593. mcglynn tp, salinas dj (2007). phosphorus limits tropical rain forest fauna. biotrop., 39: 50-53. mitchell jd (2002). termites as pests of crops, forestry, rangeland and structures in southern africa and their control. sociobiol., 40: 47–69. nakasongola district state of environment report (2004). nakasongola district council,http://www.nemaug.org. nash sm, anderson pj, whitford gw (1999). spatial and temporal variability in relative abundance and foraging behavior of subterranean termites in desertified and relatively intact chicuahuan desert ecosystems. appl. soil ecol., 12: 149-157. okwakol mjn, sekamatte mb (2007). soil macrofauna research in ecosystems in uganda. afr. j. ecol., 45(suppl. 2): 2–8. pearce mj (1997). termites: biology and pest management. university press, cambridge, uk, 172 p. reich pb, oleksyn j, modrzynski j, mrozinski p, hobbie se, eissenstat dm, chorover j, chadwick oa, hale cm, tjoelker mg (2005). linking litter calicium, earthworms and soil properties: a common garden test with 14 tree species. ecol. lett., 8: 811-818. sekamatte mb (2001). termite situation on crops and rangelands in nakasongola district. a report submitted to the environmental protection and economic development (eped) project, kampala, uganda. ter braak jfc, verdonschot mfp (1995). canonical correspondence analysis and related multivariate methods in aquatic ecology. aquat. sci., 57/3. waren mw, zou x (2002). soil macrofauna and litter nutrients in three tropical tree plantations on a disturbed site in puerto rico. for. ecol. manage., 170: 161-171. webb gc (1961). keys to the genera of the african termites. ibadan university press, ibadan, nigeria. wood gt (1991). termites in ethiopia: the environmental impact of their damage and resultant control measures. ambio,, 20: 3-4. xlstat (2011). http://www.addinsoft.com. yates cj, norton da, hobbs rj (2000). grazing effects on plant cover, soil and microclimate in fragmented woodlands in southwestern australia: implications for restoration. austr. ecol., 25: 35-47. 1 in ternationa l scholars journa ls african journal of environmental economics and management issn 2375-0707 vol. 11 (1), pp. 001-005, january, 2023. available online at www.internationalscholarsjournals.org © international scholars journals author(s) retain the copyright of this article. full length research paper effect of cement dust pollution on the vascular cambium of juglans regia (l.) bilal ahmad wani* and amina khan wood science laboratory, department of botany university of kashmir, hazratbal, srinagar –190006, india. accepted 15 september, 2022 woody trees increase in girth by the activity of meristematic tissue called vascular cambium. the vascular cambium comprises fusiform and ray initials, which give rise to vertically oriented elements that is, vessels, fibers, tracheids etc. and horizontally oriented elements that is, rays. the present study reveals that there is reduction in dimensions and proportions of fusiform and ray initials in juglans regia growing under impact of cement dust pollution. key words: vascular cambium, cement dust pollution, juglans regia. introduction the activity of vascular cambium is not uniform throughout the year and is determined by the interaction of internal and external factors (philipson et al., 1971; larson 1994; iqbal 1994; grotta et al., 2005) . with rapid industrialization the environment is degrading day by day effecting air, water and soil. the forests are in no way lagging behind in such activity. trees are mostly affected by the air pollution as it changes internal physiology leading to growth inhibition and cause visible injury and death of plant. number of worker have studied the vascular cambium of trees (dave and rao, 1982; ghouse and iqbal 1975, 1977; ghouse et al., 1980; han and woong, 1993; iqbal 1990; khan et al., 1988; khan, 2001; paliwal and yadav, 1999; paliwal et al., 2002; rao and rajput, 1999; rao et al., 1996) but little is known about the activity of vascular cambium in trees growing under pollution (berlyn and battey, 1985; creber and chaloner, 1990; khan, 1982) though a few attempts have been made to explain the formation of xylem in conditions affected by air pollution (bauch, 1986; de kort, 1986; evertsen et al., 1986; ghouse et al., 1984a; b; kottzenburg and knigge, 1987; mahmooduzzafar and iqbal, 1993; mahmooduzzafar et al., 1986; wahimann et al., 1986). keeping in view the *corresponding author. email: arfee.b@rediffmail.com, woodscience.2005@gmail.com. above observations an attempt was made to study the effect of cement dust pollution on the vascular cambium of juglans regia. it is one of the most important temperate dry fruit trees of j and k state, spread over an area of 599.00 ha. producing 83, 399 metric tones of fruit annually (anonymous, 2001) . besides its fruit production, almost every part of tree is useful. the wood is highly prized, used in making of high quality furniture, carving items, cabinets, musical instruments and in rifle butts (gamble, 1972). materials and methods cambial sample along with some bark and sapwood of 1 to 2 inch 2 size were collected from main trunk of j. regia belonging to family juglandaceae growing under the environmental stress of cement dust pollution near khrew cement plant, khrew, district pulwama, kashmir, india while healthy plants growing in natural conditions from wahab sahaib, shar, district, pulwama, kashmir. the geographical location along with other characteristics of the selected sites and material are shown in table 1. twenty samples were taken from 5 trees of comparable age and vigour under one environmental conditions in the same month of the year. samples were fixed on spot in formalin aceto-alcohol (f.a.a) and then transferred to 70% ethanol after 72 h for preservation. samples were sectioned in tangential plane at a thickness of 10 to 15 µm. sections were stained in tannic acid, ferric chloride (foster, 1934) and mounted in canada balsam (sass, 1958). measurements of cambial initials were carried out from tangential longitudinal sections with the help of an ocular micrometer scale under the specific magnification of compound microscope. an average of 500 measurements was 2 table 1. the geographical location along with other characteristics of the selected sites and material. factor site i (khrew) experimental site ii ( shar-i shali) control north latitude 30º 12´ 30º 10´ east longitude 75º 35´ 75º 30´ elevation (m) 1750 2000 soil sandy clay sandy clay age in years 1013 1013 figure 1. a: t. l.s of j. regia in normal environmental conditions showing nonstratified cambium. b: t.l.s of j. regia growing under cement dust pollution. taken on random basis. the mean of cell dimensions were determined after pooling the readings obtained from different samples. the ratio of ray and fusiform initials was calculated by ghouse and iqbal (1975). results the vascular cambium of presently investigated species of j. regia is made up of two type’s initials that is, fusiform and ray initials. the fusiform initials were elongatedspindle shaped elements which overlap with one another at considerable distance thus rendering the cambium non-stratified. the walls of the fusiform initials bear primary pit fields and have distinct plasmodesmata connections with the contiguous elements, especially with the ray initials. the radial walls of fusiform initials are slightly thicker than the tangential ones and appear distinctly beaded during dormancy (figure 1a). the length of fusiform initials ranges from 363 to 414 µm under normal growth conditions and 327 to 378 µm under cement dust pollution. the width of these cells is found to vary from 16 to 21 µm and 14 to 20 µm, respectively (table 2) . the ray initials which occur in distinct groups generally form cambial rays which vary in width and height to a considerable extent in the different environmental conditions (figure 1). two or more cambial rays often fuse together to form complex aggregates running to a great height and covering the length of one or more fusiform initials. a fusiform initial can also intrude into a unit of ray initials by apical intrusive growth thus splitting it into two parts. the size of ray initials also varies in different environmental conditions. the anticlinal and periclinal diameter of these initials ranges from 24/30 24/33 µm in normal 3 table 2. dimensions of cambial initials under different environmental conditions. fusiform initals ray initials length width anticlinal periclinal ratio of fusiform initals to ray condition µm µm µm µm µm range normal 363-414 16-21 24-30 24-33 78/22 pollution 327-378 14-20 23-30 22-31 76/24 trees while in cement dust pollution, it ranges from 23/30 22-31 µm (table 2). depending on the cambial make-up the ratio of ray and fusiform initials differ in different conditions of environment. in normal trees, the ray initials constitute about 22% and that of fusiform initials constitute about 78% while in trees growing in cement dust pollution it constitute about 24 and 76%, respectively. discussion air pollutants, responsible for vegetation injury and crop yield losses, are causing increased concern (fuji, 1973). air pollution has become a major threat to the survival of plants in the industrial areas. rapid industrialization and addition of the toxic substances to the environment are responsible for altering the ecosystem (ara et al., 1991; ahmad et al., 1986). the cement industry also plays a vital role in the imbalances of the environment and produces air pollution hazards. the cement production process is accompanied with the emissions of considerable amounts of dust which causes changes in the growth conditions of forest trees. dust falling from the atmosphere to the forest ecosystem is deposited mostly on leaves (parn, 2006), and effect photosynthesis, stomatal functioning and productivity (nanos and ilias, 2007). the reduced photosynthetic activity retards cambial activity and consequently xylem and phloem production (wahlmann et al., 1986). transpiration rate decreases and assimilation processes are starved of minerals (halbwachs, 1970) . the activity of cambium depends on the availability of water, starch, soluble sugars, minerals and growth hormones etc. (berlyn and battey, 1985; iqbal, 1995; riding and little, 1984. in the presently investigated plants, arrangement of cambial initials depicts a clear nonstratified structure as in the majority of vascular plants (figure 1). in this type of arrangement, the fusiform initials overlap with one another at considerable distance, thus rendering the cambium non-stratified e.g. salix, populus, eucalyptus (dwivedi, 1982). bailey (1923) found that the length of fusiform initials in non-stratified form vary from 460 ti 4440 um. the present observations regarding this aspect do not agree with the limits of bailey’s above observations. bartwal et al. (1983); ghouse and iqbal (1975); ghouse et al. (1980); khan (1980); khan (2001); mahmood (2001) and wani and khan (2008; 2009) have found the length of fusiform initials to fall shorter than the limits for the non –stratified cambium. among the plants of j. regia investigated in the present study, those growing under the influence of cement dust pollution has been found to possess comparatively short fusiform initials than those growing normal conditions. the shortening of fusiform initials is due to decreased transpiration, because water content is reduced in the stem and fusiform initials readjust their dimensions to decrease in size. the short size of fusiform initials is coupled with structural shortening of other features of the bark and wood namely, the size and structure of sieve tube members, vessel elements, xylem and phloem rays and the amount and distribution of parenchyma so as to support the capillary action in the lumen (esau, 2002; fahn, 1997). the present findings go in agreement with earlier workers (creber and chaloner, 1990; ghouse et al., 1985, 1989; iqbal et al., 1987a; b; khan, 1982; mahmooduzzafar et al., 1986; yunus and iqbal, 1996). the analysis of dimensions of ray initials in the present study indicates that they undergo a decrease in the polluted environmental conditions as compared to healthy trees. while, the relative proportion of the ray initials to the fusiform initials has been observed to increase from 22% in normal condition to 24% under cement dust pollution. this clearly shows an increase in the number of ray initials with decrease in their anticlinal and periclinal diameters under the polluted environment (creber and chaloner, 1990; romberger et al., 1993; yunus and iqbal, 1996). earlier workers show that the fusiform initials constitute more than 90% of the cambial cylinder (bailey, 1923; butterfield, 1972; margaris and papadogianni, 1977). but this report goes in agreement with bhat et al. 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(2), pp. 001-003, february, 2022. available online at www.internationalscholarsjournals.org © international scholars journals author(s) retain the copyright of this article. short communication new report from presence and distribution of allactaga firouzi in iran saeed mohammadi1* and gholamreza naderi2 1 department of environmental sciences, faculty of energy and environment, sciences and research branch, islamic azad university, tehran, iran. 2 department of environment, islamic azad university, ardabil branch, iran. accepted 29 october, 2021 the iranian jerboa allactaga firouzi (womochel, 1978) is one of the rarest rodent species in the world and it has been reported exclusively from a single site in central iran. due to the lack of enough information on the ecology of this species, its conservation status was changed to “data deficient” category in late 2008. no additional data on a. firouzi was published since its first description by womochel. here we report the results of recent intensive survey work in south of shah-reza city that yielded several new localities for this species. new localities of a. firouzi were identified. key words: allactaga firouzi, iran, shah-reza, data deficient. introduction iran is located in the palearctic realm and is considered the center of origin for many of the world’s genetic resources. although, the country’s natural resources have been carelessly exploited over the past, environ-mental deterioration has increased markedly in the past few decades (fisher, 1968). little information about the current distribution of the iranian jerboa allactaga firouzi has been available and published since the first initial survey by d. r. womochel (1978). the iranian jerboa is one of the 13 species of allactaga genus the subfamily allactaginae. this species as an endemic iranian mammal recorded for the first time south of shah-reza in isfahan province. the iucn/ssc classifies the species as ‘data deficient’ (iucn, 2009). this species is active from 11:00 pm to 5:30 am in early spring to late summer but in midsummer, its activity times are restricted to 9:00 pm to 4:00 am (naderi et al., 2009). the first collections of iranian jerboas were made by the w. s. and j. k. street expedition to iran in 1968 (womochel, 1978) . no additional data on a. firouzi was published since first description. he pointed out populations populations *corresponding author. e-mail: mohammadi7517@yahoo.com. tel: +989155427517. restricted to a village 18 miles south of shah-reza. we found specimens after three-decade collection gap near the mirabad village in 22 km shah-reza to abadeh highway (31° 56’ 02’’ n, 52° 02’ 05’’e; 2198 m) (figure 1). current knowledge of the distribution of a. firouzi shows that, the species inhabits unique habitats in iran (figure 2). we report the results of a recent intensive survey south of shah-reza that yielded several new localities for the species. experimental procedures field surveys were done in typical habitat of semi-arid grazed steppe (surface covered by bare soil and/or scarce shrub and grass vegetation) from april 2008 to may 2009. the weather is markedly seasonal with a dry season between may and september (<10% of the annual precipitation). vegetation types comprise different shrubs such as anabasis aphylla, artemisia siberi, peganum harmalla and scariolla orientalis. the area is used as grazing grounds for domesticated sheep and goats. according to the available information naderi et al. (2009) reported that a. firouzi had been recorded in a grassland habitat in the mirabad plains. for recognition of the species we used a spotlight and characteristic features of a. firouzi that mentioned by womochel (1978). because jerboa is not trappable in live-traps so we caught them with a hand net, using a searchlight and motorcycle. a 30 cm diameter hand net was used for catching. 2 figure 1. geographic distribution of a. firouzi in iran. figure 2. iranian jerboa (mammalia: dipodidae). photo by: saeed mohammadi. results and discussion totally 24 individuals were captured and then released in 65 nights of trapping. the first site is located within the veshare plains at 2054 m elevation 31°43’’ n, 52° 02’’ e. 6 species were found in a desert with semi-open canopy next to village. the surface was flat. second locality was at 31° 44’’ n, 52° 08’’ e, in a degraded area close to the shah-reza to abadeh highway. the vegetation at this site was made up by a. aphylla and a. aucheri. the area is flat and probably permanently dry. also brown (1980) reported that hotson’s jerboa a. hotsoni was caught in more barren areas. he showed a negative correlation between vegetation cover and a. hotsoni occurrence in kavir national park. soil texture and altitude were found to be the main factors affecting the distribution of this species (naderi et al., 2009) . other collecting sites were located near abadeh city in fars province at 31°29’’ n, 52° 15’’ e. hassinger (1973) found a. hotsoni below 1000 m, whereas euphrate jerboa a. euphratica occurred between 1800 and 3200 m in afghanistan. womochel (1978) also reported a. hotsoni below 1000 m in clayloess deserts with sparse, clumped vegetation, but small five-toed jerboa a. elater lives in salty semiarid areas with various kinds of halophytes. based on our data we support the ‘red list‘ category of endangered for a. firouzi based on criteria (iucn, 2009) mainly because of its small area of occupancy, its severely fragmented 3 figure 3. iranian jerboa killed in road incident. photo by: saeed mohammadi. distribution, and the decline of its habitat in east mirabad plains that it is necessary to organize continuous monitoring of the iranian jerboa population. we found 3 jerboas were to be killed in road accidents (figure 3). the iranian jerboa has been reported exclusively from a single site and is therefore one of the rarest rodent species in the world. our data highlight the importance of flat area from south of shah-reza in isfahan province to abadeh in fars province, which may harbor a larger species diversity than is currently known, including regional endemics such as the iranian jerboa. acknowledgements authors would like to express gratitude to m. mostafavi and late dr. m. tarahomi for helping to field activities. references brown re (1980). rodents of the kavir national park, iran. mammalia, 44: 89-96. fisher wb (1968). the cambridge history of iran, vol. 1. cambridge university press. hassinger jd (1973). a survey of the mammals of afghanistan resulting from the 1965 street expedition (excluding bats). fieldiana zool., 60: 1-195. iucn (2009). iucn red list of threatened species. version 2009. 2. www. iucnredlist.org. naderi gh, hemami mr, riazii b, alesheikh aa (2009). notes on ecological peculiarities of iranian jerboa, allactaga firouzi womochel, 1978 (mammalia: dipodidae). zool. middle east, 47: 21-28. womochel dr (1978): a new species of allactaga (rodentia: dipodidae) from iran. fieldiana zool., 72(5): 65–73. 1 in ternationa l scholars journa ls african journal of environmental economics and management issn 2375-0707 vol. 11 (1), pp. 001-006, january, 2023. available online at www.internationalscholarsjournals.org © international scholars journals author(s) retain the copyright of this article. review history of river channel modifications a review m. a. mohammed-aslam1* and a. balasubramanian2 1 department of earth sciences, pondicherry university, puducherry605014, india. 2 department of studies in geology, mysore university, manasagangotri, mysore -570 006, karnataka, india. accepted 9 august, 2022 many river basins have witnessed episodes of modifications and shifts in its courses in the geological past. the study of these aspects can be regarded as part of a trend towards the understanding and explanation rather than depiction of how rivers adjust, under varied terrains of landform behaviour. the methodological appraisals that arise from such intensive research are illustrated in this paper using a detailed investigation of river reach with a special emphasis on palaeochannels and channel modification. the proper evaluation of the past works on channel modifications is expected to provide more insight into not only the theoretical concepts of channel metamorphosis but also to the realistic development of natural resources. for successful planning and management of the water resources, it is essential to evaluate the actual surface and subsurface signatures of the dynamic river systems. key words: channel modification, river, palaeochannel. introduction palaeochannels are the elongate, lobate or sinuous fluvial landforms representing the drainage path in the geologic past; with an expected aerial extent from a fraction of a kilometer to many kilometers in length. large rivers are arteries which are critical to the life of diversified landscapes they pass through. the rivers are largely instrumental in shaping the landforms both by means of erosion and deposition. although rivers are mere narrow ribbons across the continents, their network direct and regulate one of the most significant activities of nature. rivers form the vital components of the hydrological cycle. the increasing number of settlements and population necessitated the suitable methods of exploitation of water resources very significantly. this also needs a comprehensive hydrogeological analysis. an appraisal of the existing groundwater conditions in any fluvial system helps the supplementary development of resources in order to meet the projected demand. since the advent of modern techniques in the field of earth science, it has become obvious that any shift in the present river course or distribution of abandoned channels is considered to be the topics of wide discussion. a trend has also been set *corresponding author. e-mail: maslam.in@gmail.com. in the search of old channel courses which can be used to find the promising sites for groundwater exploration. many features can be attributed to successfully recognize the existence of palaeochannels. features of meanderplains like, old channel scars, point bar deposits, meander scrolls, meander loops, ox-bow lakes, and water filled abandoned channels; variously dissected fluvial deposits; elongate, low sinuous ribbons of sediment deposits, characteristic narrow mosaic of sedimentary deposits and type and texture of vegetation can provide reliable information about the nature of palaeochannels. since the groundwater potentialities of such zones are remarkably excellent, anomalous growth of healthy plants in high density is also expected. scope and objectives the continuing channel modifications and change in river courses have got a greater implication on the potentiality of water resources. for successful planning and management of these resources, it is important to assess the actual surface and subsurface signatures of the dynamic river systems. the scope of the present study is to assess the development in the field of channel modifications and palaeochennels, which form one of the important hydrogeological domains. this study involves 2 the analysis of the function played by geology and structural characteristics in the channel shifts, palaeochannels and their hydrogeological aspects and evaluation of the mechanism of drainage metamorphosis. in the recent past, proper attention has been paid particularly in many parts of the world to characterize the palaeochannels or the old courses of the major rivers. an assessment of the existing sources of earlier studies has been made and presented in this paper. discussion historical developments a clear description of river channel adjustment was given by clemmens (1883) (was probably the first?). the suspected changes inferred before 1900 were not investigated in the subsequent years. after 1900 the davisian explanation prevailed and dominated the geomorphological thinking about rivers. this interpretation involved the assumed changes which occurred during the cyclic evolution of landscape development. remarkable beginning was given by sonderreger (1935). the concept further was oriented towards the measurement of change. one of the greatest and outstanding problems for a geomorphologist is to differentiate between the evolutionary sequences of chance and adjustments inspired by direct and indirect human activities. collections of papers on river morphology (schumm, 1972a) and on environmental geomorphology demonstrate that some research was completed during the past century which is pertinent to river channel change. a number of methods are available for the identification of channel changes and these are clear from the (1) empirical measurements, (2) historical methods, (3) dating techniques, and (4) space-time substitution. channel modifications any adjustment in the channel forms and processes will lead to a typical hydrogeological and hydrogeomorphological set-up. the earliest work on river change and morphology were carried out by schumm (1968), followed by dawson and tilley (1972); hickin and nanson (1975) and lewin and weir (1977). gregory (1977) was probably the first to review the context of river channel changes by summarizing the results of various studies. studies on channel modifications induced by natural phenomena like floods, tectonism and high meandering are a few. alluvial rivers react to valley slope deformation caused by these factors in various ways depending on the rate of amount of surficial deformation and on the nature of river. significant among them could be seen in ritter dale (1979), malcolm anderson and ann calver (1980), carson (1986) and shunji ouchi (1985). changes in the channel geometry caused by human intervention with fluvial processes have received considerable attention (gregory, 1977). richards and greenhalgh (1984) discussed the limitations of the spatial interpolation method of identifying and interpreting the channel modification. kesel richard and yodi’s elaine (1992) studied the effects of human modifications on sand-bed channels in south western mississippi. mohammed-aslam et al. (2006) applied linear mixture model for studying alluvial plain that contains palaeochannels. petts (1980) has suggested a few analytical methods for the river channel changes. saini et al. (1980) have mapped out the abandoned channels of mendha river in orissa using landsat mss data. they have attributed that the sand movement towards the northeast has forced the river to change its course. the other notable work done on river changes could be seen in antczak (1981) and ferguson and werrity (1983). the morphology and hydrology of ancient meandering fluvial systems have been assessed by means of the physical parameters by gardner-thomas (1983). dury (1984) explained the abrupt variation in the channel width along a river and proposed a functional relationship of channel properties. watkins and simmons clyde (1984) compared the hydrological conditions of the chicod creek basin, before and during channel changes. rajaguru and kale (1985) used the geomorphological, archaeological, palaeontological and c14 dating information in deriving the buried and exposed alluvial deposits of upper parts of krishna, bhima, and godavari rivers of western maharastra. ramasamy et al. (1992) pointed out the river migration in northern tamil nadu with the evidences from satellite data, archaeology and tamil literature. the sinuous nature of river meanders and their complexities with fractal dimensions of alluvial and non-alluvial channels have been conceptually analyzed by keith montgomery (1996). recent studies on channel modifications are seen in hasegawa kazuyoshi (1989), mason robert et.al.(1990), singh et.al(1990), ramasamy et.al.(1991), fried alan (1993), xue-chunting (1993) , mohammed-aslam and balasubramanian (2001, 2002), mohammed-aslam (2003), mohammed-aslam et al. (2002, 2003, 2006) and carolyn et al. (2009). palaeochannels well-preserved palaeodrainage systems in the major rivers have dragged the attention of enthusiastic workers mainly because of the valuable economic deposits resulted from the hydrochemical response with sediments and enriched groundwater resources. the general features of palaeochannels were brought into the limelight by schumm (1972). later in the year 1979, wynn had explained the applications of electromagnetic methods in locating the buried palaeochannels. bachman and wilson 3 (1982) published a report on the palaeochannels discovered over the delmarva peninsula in usa. gregory (1983) has illustrated the different sections come under palaeohydrology. the geometrical aspects of palaeochannels and their flow patterns have been analyzed by marc b edwards et.al (1983) using the vertical sections of channels and their floodplains. narasimhan (1990) and absar-ahsan et al. (1991) have investigated the palaeochannels of palar river and concluded that the uplift of the terrain have occurred during the quaternary periods. a few pioneering works have been done on palaeochannels and their impact on mine stability. such studies are seen in guion paul (1987), ingram david and chase frank (1987). glacial palaeochannels of susquehanna river in the chesapeake bay area were studied by colman et al. (1988). dimichele william and philips tom (1988) pointed out the palaeoecology of herrin coal swamp adjacent to the walshville palaeochannel. other remarkable work done on palaeochannels was found in qin-yunshan et al. (1988) ; brazier and balantyne (1989); willis (1989, 1993); mohammed-aslam and balasubramanian (2001, 2002); mohammed-aslam (2003); mclaren et al. (2004); mohammed-aslam et al. (2002, 2003, 2006) and robert (2009). castaldini (1990) has brought out the palaeochannel network of po river, italy, using remote sensing, archaeological, historical and prehistorical data. he has also dated the roman settlements aligned along its old courses, archaeological remains of bronze age, iron age etc. and concluded that the po river has wandered almost widely during 4000 5000 years ahead of the present. david et al. (1991) used the transient electromagnetic soundings and terrain conductivity meter measurements for mapping the palaeochannels geometry in the al jaww plain in eastern abu dhabi emirate. du-xiaodi et al. (1991) made an effort on palaeochannel reconstruction based on sedimentary characteristics of the fluvial facies. there are a few examples in the literature for palaeochannels and further notable observations are seen in lihuanchun (1991); richard et al. (1992); shevchenko (1992) and smith et al. (1993). a few authors have attempted to identify the major palaeochannels in different river basins of indian sub continent. the lost courses of river saraswati were mapped by ghose et al. (1979). remote sensing techniques have been successfully utilized in studying the palaeochannels (philip et al., 1991; ramasamy, 1991; sarma, 1993; mohammed-aslam and balasubramanian, 2001; mohammed-aslam et al., 2006). tiwari (1992) estimated the groundwater potential zones in a part of the thar desert by demarcating the palaeochannels. babu (1975, 1986) has divided the cauvery basin into four main physiographic zones and made a detailed study about the past and present characteristics of cauvery delta. rao (1982) discussed the morphology and evolution of modern cauvery delta. ramasamy (1991) employed remote sensing techniques for studying the river delta in tamil nadu. radhakrishna (1992) described the geological past of cauvery basin and observed its drainage architecture and fluvial anomalies. recent investigations on palaeochannels have diversified approach. seismic-reflection identification of susquehanna river paleochannels on the mid-atlantic coastal plain was attempted by robert et al. (1994). jean-christophe et al. (2003) used three classical geophysical methods (electromagnetic profiling supplemented by electrical soundings, electrical resistivity tomography and ground penetrating radar [gpr]) to define alluvial bodies and palaeochannels. the paper by david (2003) discussed the properties of the buried floodplain at six sites in the loup river basin, to consider why the properties of buried flood-plain vary from site to site, and to evaluate possible reasons why the loup river flood-plains stabilized 5500 years ago. extensive works on palaeochannels of ncp (north china plain) are seen in works of wu chen et al. (1996a, 1996b, 1996c) and xu qinghai et al. (1996a, 1996b). ellis and brown (1998) illustrated how archaeomagnetic dating can be used for palaeochannel fills within floodplain sequences. the sites investigated are palaeochannels associated with the mediaeval braided/anastomosing channels of an unstable reach of the river trent at hemington, north-west leicestershire. the paper from ogbaghebriel et al. (1998) presented a geomorphologic–stratigraphic analysis of a travertine dammed lacustrine–swampy sedimentary sequence, composed of clay, peaty layers and phytoclastic travertine sands, deeply incised by the mai maikden river, on the highlands of tigray (northern ethiopia) where a few palaeochannels were identified. dates for sediment deposition have been obtained for a number of abandoned channels with modern features on the upper murray, kiewa, ovens and goulburn rivers, and from palaeochannel deposits on the upper murray river just west of albury by ralph et al. (2001). a research paper from mauro (2002) discussed the changes in fluvial dynamics that started from late pleistocene and early holocene due to distinct climatic changes. imaging of a large palaeochannel by fielding et al. (2003) on the northeastern australian continental shelf by a series of shallow seismic reflection profiles preserves a rare insight into the stratigraphic record of falling sea level during the last glacial period. abandoned channel belts, ponds and point bar deposits of palaeochannels in the interfluve regions of central ganga plain and the changes in the morphohydrologic conditions during the latest pleistocene–holocene were carried out by pradeep et al. (2003). david and andy (2004) used a method using coleoptera remains recovered from a palaeochannel fill at spalford meadows in the lower trent valley, for the reconstruction of river histories of trent basin, uk, a key factor in understanding the distribution of valley floor archaeological settlement patterns. lewin et al. (2005) classified holocene alluvial archive of great britain by sedimentation unit (channel sediments, palaeochannel fills, floodplain surface sediments, floodbasins and colluvial 4 deposits) and alluvial ensemble (fans and cones, upland gullies and streams, braided systems and active/inactive meandering and anastomosing systems). based on the observation from high-resolution 3d seismic data sets, gay et al. (2006) documented the subsurface reservoir architecture and organization of a portion of the oligocene–miocene stratigraphy within the congo basin, offshore southwestern africa, and identified four levels of turbiditic palaeochannels, which are separated by low-amplitude continuous reflectors interpreted as hemipelagic sediments. recently, olga et al. (2006) made use of the morphological, geological, geochronological and palynological methods and showed that the landscape, climate and hydrological history of the seim river basin. vincent et al. (2006) employed the archaeological analysis and dendrochronological dating to discuss the four palaeo-flooding events occurred during a short time period between ad 20 and ad 145/146. these geoarchaeological observations focus on floods that do not seem to have considerably affected human occupation in the rhine floodplain. conclusions the application potential of geological, geophysical, remote sensing and related techniques in characterizing the palaeochannels and channel modifications has been attempted and demonstrated in this work. the proper appraisal of the past works on palaeochannels and channel modifications expected to provide more insight into not only the theoretical concepts of channel metamorphosis but also to the practical development of natural resources. micro-level and sector based investigations of natural resources are now given much emphasis that are related with channel shifting and palaeochannels. integrated studies are encouraged in order to assess and evaluate the quantitative and qualitative aspects of palaeocahannels. references absar a, subramanian ks, narasimhan tn (1991). paleochannels of the palar river west of madras city; possible implications for vertical movement discussion and reply. quarterly. j. geol. mining. metallurgical. soc. india., 37(2): 184-186. antczak b (1981). morphology and deposits within the braided palaeochannel pattern, site 2: zabno. in kozarski, s., and tobolski, k. 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xue-chunting (1993). historical changes in the yellow river delta, china. marine. geol., 113: 3-4, 321-329. xu q, wu c, zhu x, yang x (1996a.) palaeochannels on the north china plain: stage division and palaeoenvironments. geomorphol., 18(1):15-25. xu q, wu c, yang x, zhang n (1996b). palaeochannels on the north china plain: relationships between their development and tectonics. geomorphol., 18(1): 27-35. . in ternationa l scholars journa ls african journal of environmental economics and management issn 2375-0707 vol. 7 (8), pp. 001-010, august, 2019. available online at www.internationalscholarsjournals.org © international scholars journals author(s) retain the copyright of this article. review gaps, barriers and bottlenecks to sustainable land management (slm) adoption in uganda n. banadda department of food science and technology, makerere university, p. o. box 7062 kampala, uganda. e-mail: banadda@agric.mak.ac.ug. accepted 20 january, 2019 land degradation is a global problem and a great challenge to sustaining the biological, economic and social services provided by various ecosystems. this work assessed the causes of land degradation in uganda and identified gaps, barriers and bottlenecks that hinder sustainable land management programmes adoption. the major human-induced types of land degradation in uganda included soil erosion, soil fertility decline and habitat loss. the findings of this study also point to the fact that, the decline in soil fertility affected about 88% of the rural population that subsist on less than 2 ha per family constituting over three million small-scale holdings. in addition, this work traced the various policies, plans, programmes and strategic frameworks formulated during the period of economic growth in uganda and assessed the main constraints therein that hinder up/out scaling best land management practices. key words: land use, land policy, sustainable land management, river basin, uganda. introduction land degradation is a global problem and a great challenge to sustaining the biological, economic and social services provided by various ecosystems. the negative impacts of land degradation undermine livelihoods and their economic well-being, the environment and the nutritional status of more than one billion people in developing countries (smyth and dumanski, 1993). it is estimated that 12.5 million hectare (ha), which is 62.5% of land area in uganda, are agricultural area (ifpri, 2001). however, ifpri (2001) also estimated that 97% of uganda land suffers from some form of human-induced land degradation problems indicating that, the land degradation problem extends far beyond the arable land. the major human-induced types of land degradation in uganda in terms of priority include soil erosion, soil fertility decline and habitat loss (mwle, 2006). the estimation of economic consequences of land degradation in uganda is not comprehensive. however, there is qualitative evidence that land degradation is linked to stagnating and decreasing yields in food (cereals and bananas) and cash crops (olson, 2004). in addressing land degradation, uganda has over the years piloted best practices from research and appropriate technology development such as, the farmer field school as strategic entry point for sustainable land management (fao, 2002). uganda has also benefited from the partnerships with bilateral and multilateral donors in transboundary programmes, for example, the kagera transboundary agro-ecosystem management, the nile basin initiative, to mention but a few. although, uganda has made some commendable progress in piloting best practices in the various agro-ecological zones, this study identified various constraints that impede wider geographic replication of these success stories. such impediments are gaps in knowledge and technological limitations, policy/institutional related barriers, low investment for the expansion of best practices and sociocultural constraints. barriers, gaps and bottlenecks related to institutional and governance, economic and financial issues, technology and knowledge and social/behavioral considerations need to be addressed more comprehensively through adequate investment opportunities within national development frameworks. the objective of this work was to assess the causes of land degradation in uganda and identify gaps, barriers and bottlenecks that hinder sustainable land management mailto:banadda@agric.mak.ac.ug (slm) programmes adoption. land degradation and best practices land degradation in uganda the underlying causes of land degradation in uganda are of socio-economic nature which are difficult to measure and include population pressure, poverty and policies (matagi, 2002). in this section, the major human-induced types of land degradation in uganda are discussed. soil fertility decline among other issues, this study also focused on soil fertility in uganda. it suffices to note that, the decline in soil fertility is affecting about 88% of the rural population that subsist on less than 2 ha per family, constituting over three million small-scale holdings. soil fertility decline is a serious problem particularly in the highlands of uganda such as kabale, kisoro and the northern slopes of muhavura mountains. a strategy to prevent, reverse or control land degradation due to soil fertility decline therefore, should prioritize the above areas for the introduction of slm related initiatives. for the case of cereal yield trends, the yield per area had remained more or less stagnant (1.5 metric tons per ha) over the last 30 years, while area under cereal production has doubled from about 800,000 ha in 1990 to 1.6 million ha (faostat, 2005). the area under banana cultivation has increased (1975 to 2005) from 100,000 ha to 135,000, while the annual yield has increased from 3.3 to 4.5 tons/ha, indicating a more or less stagnant or small increases in yields, which is linked to area increase. the area under cassava production had more or less remained around 0.5 million metric tons between 1980 to 1999 and at around 1.5 million metric tons between 2002 and 2005. the rise in production per hectare was probably as a result of improved cultural practices, adoption of good agronomic practices and variety improvement. there are also indications that, farmers are changing crop choice from banana to root crops due to decline in soil fertility. the traditional center of banana production in mpigi and mukono districts in central uganda has been experiencing declining yields and farmers are switching to cassava and sweet potatoes (olson, 2004). meanwhile, banana production is moving towards western uganda. if not addressed in a sustainable manner, crop production will continue to impact negatively on soil fertility and the quality of water resources since by consequence soil erosion sets in (tonderski, 1996). soil erosion soil erosion is the most serious and widespread form of land degradation in uganda with estimated average annual soil losses of more than 30 tons per ha in highlands (ifpri, 2004). the severely affected districts included kotido, moroto, northern luwero, mbale, kisoro, mbarara, kabale, mukono and arua, where fragile vegetation cover had been destroyed by overstocking and overgrazing. among other factors, the declining fish harvest from lake victoria is also attributed to siltation and eutrophication partly due to soil erosion (okwerede et al., 2005). in other words, the eroded silt ends up in water bodies. an increase in turbidity, associated with the suspended soil material in the water has a potential impact on the tourism industry (toumazis, 1995). from the foregoing, it is desirable to raise some reflections on the increasing pollution from land degradation in uganda. besides tourism, the socio-economic implications of land degradation in general and soil erosion in particular include increased rural poverty, increased vulnerability of communities to food insecurity, increased cost of food production, declined (foreign) revenues due to low fish harvest, rural to urban migration and encroachment into gazetted natural reserves. in fact, by the 1950s and the early 1960s popular fish species ngege (oreochromis esculentus), had diminished so severely that, they had become commercially extinct (kyomuhendo, 2002). furthermore, between 1969 and 1977, the east africa water fisheries research organization (eaffro), initially in collaboration with united nations development programme/food and agriculture organization, carried out a fish stock survey of lake victoria. a comparison of the trawl catch data made in the nyanza gulf in 1976 with earlier records of 1969/1970, showed a reduction in stock densities of the most important species, tilapiines as well, l. victorinus, barbus species, mormyrids and s. mystus were virtually absent (ogutu, 1990). traditional lifestyles of lake shore communities have been disrupted and are crumbling (banadda et al., 2009). in 15 years, the population of kampala city had risen from 775,000 in 1991 to 1.5 million in 2006 (ubos, 2006). as the population grew and fishing methods advanced, overfishing also became a problem and catch sizes also dropped (chege, 1995). habitat loss another serious land degradation type is loss of habitat through deforestation and encroachment of agriculture into protected areas and rangelands. the problem is most severe in eastern uganda and south western highlands. establishment of commercial ranches along the north-east to south-west cattle corridor and privatization of communal land for shifting agriculture have contributed significantly to the habitat loss (maaif, 2004). of importance is overgrazing and over-harvesting of vegetation in rangeland and forests for wood fuel and timber. the present forest cover in uganda is estimated at about 3.6%, which is about 20% of its original value in 1890, as a result of deforestation (maaif, 2004). furthermore, maaif (2004) estimated that the forest cover decline in uganda was 1.95% per annum. deforestation has resulted in widespread soil erosion, floods, droughts and desertification (olson, 2003). as mentioned in the preceding section, overall soil erosion is the lead cause of human-induced land degradation in uganda, further resulting in serious environmental implications (mwle, 2006). this has been evident in the cattle corridor of uganda which includes the districts of moroto, kotido, mbarara and northern luwero. soil erosion is responsible for the loss of land productivity in eastern uganda, siltation of lake albert and lake victoria and rivers and the associated problems of eutrophication (mwle, 20o6). this problem is severe where former wetlands adjacent to lakes and rivers have been converted to cropping and animal production. two pollution issues related to increased animal production are occurred, that is, fecal contamination of water bodies and non-point source related pollution (banadda et al., 2009). according to doran and linn (1979), surface runoff from grazed pasture may reach 5 to 10 times higher fecal coliform concentration than from ungrazed one. severely affected areas include manafa, kafu, nyamwamba and the nile river (mwle, 2006). heavy sedimentation experienced along the shores of water bodies is resulting in significant loss of fish production and consequently, deterioration in water quality. the loss of biodiversity and agro-ecosystem functions was reported in the kagera river basin (olson, 2004). best practices and success stories several initiatives addressing land degradation and slm in various parts of uganda have been implemented successfully and need to be up-scaled to the national level. the success of some identified best practices has been anchored on the following facts, among others; their contribution to household incomes, stakeholder participation and partnerships, collaboration and synergies dialogue and institutionalization of key breakthroughs, availability of markets for products, cost effectiveness of operations and bottom-up participatory process (fao, 2002). the key practices include: the farmer field schools (ffs) this is a significant approach for promoting improved land management in uganda. such initiatives include the farmer field schools for soil productivity improvement, conservation agriculture and nutrient monitoring in eastern uganda. payment for environmental services (pes) good ecosystem stewardship created conditions for higher productivity and greater direct environmental income, not only for the stewards (ideally farmers and other land resource managers), but also for the immediate surroundings. in uganda, several ecosystem service payments, markets and mechanisms operates mainly through agreements/collaboration between government agencies, private sector/companies and nongovernmental organizations. cases in focus include, the agreement between local communities and uganda wildlife authority for park management, payment for ecotourism services in parks and sanctuaries and planting of trees for global carbon benefits. past and ongoing initiatives of relevance to slm approach these include bee farming in sironko district in eastern uganda, community termite infestation control in rangelands and enhancing rapid information dissemination at community level through radio and internet in nakasongola district (central uganda), community-based afforestation and integrated community agroforestry in ntungamo district (western uganda), rain water harvesting for domestic use in mbarara (western uganda), integrated livestock health improvement and conflict resolution in moroto district (north-eastern uganda) and promotion of farmer innovations approach to rural development in katakwi district (eastern uganda). gaps, barriers and bottlenecks to slm adoption there are numerous sustainable land management (slm) projects/programmes aimed at addressing land degradation in uganda. these have been successfully piloted by development partners, non-governmental organizations, community-based organizations and the government of uganda. the best practices in these initiatives are ready for institutional/policy mainstreaming as well as for up-scaling and out-scaling at all levels, that is, local, national and regional. however, progress in mainstreaming of these best practices which will promote slm practices faces several barriers, bottlenecks and gaps which must be addressed. thus, some of the constraints are discussed institutional and governance constraints the institutional and governance issues are major barriers that hinder the adoption of good land management practices. the leading constraints in this category are weak land and land-use policies that are not area-specific and that do not effectively protect over 85% of the total land. this is also weakened by poor of the existing laws and regulations due to lack of technical and financial resources coupled with a lack of political will for enforcement of land related laws. there is a need to raise the national priority on the effective implementation of land laws and especially to promote land tenure systems that will encourage investment in slm related activities. this will also depend very much on the improvement of planning and implementation capacities of government institutions charged with land and land-use policy implementation. gaps and operational weaknesses have been identified in the national agricultural advisory services (naads) approach, which has not factored in issues of tenure, culture, capital and insecurity in its programmes. economic and financial constraints the adoption of good land management practices is also constrained by economic and financial factors, which largely affect the levels of investment in slm related activities. low public and private investment in research and technology and under-funding of extension services and public institutions dealing with environment and natural resources, present a serious constraint to slm adoption and mainstreaming in uganda. low national budgets do not make land degradation and slm priority issues. ultimately, it is difficult to strengthen researchextension-farmer/end user linkages that are critical for sustainable adoption of good husbandry practices. lack of economic incentives such as compensation mechanisms for environmental services is a barrier to investing in high capital and labor demanding slm technologies, such as soil and water conservation technologies. this can be attributed to a poor payment for environmental services system and weak institutionalization of payment for environmental services; best practices in uganda. one of the key lessons learnt in promoting preventive measures to combat land degradation is to put in place slm packages that link economic and financial incentives for the majority of subsistence smallholders who own less than 2 ha per household. technological and knowledge constraints despite the progress made in research and technology related to land management in uganda (ifpri, 2001, 2004; mwle, 2006), there are clear indications of technology and knowledge gaps and barriers to adoption of slm related practices. one of the constraints is lack of expertise/low capacity in extension services for land management even at institutional level [national agricultural research organization (naro)], which can be partly attributed to low investment in capacity building and financial facilitation from national external resources. the problem is aggravated by low levels of awareness and understanding among land users about the environmental impacts of land degradation and its relationship to poverty and decline in household incomes. these issues need to be addressed in future slm initiatives if long term impacts and sustainability of good land management is to be realized. the inherent vulnerability of soils to degradation under various landuse options also limits the level of application and success of good land management practices, especially because it is expensive to address them. it is therefore expedient to have areaand case-specific technological packages. social and behavioral constraints unfavorable social and behavioral characteristics among various stakeholders particularly that of farmer/pastoralists are a major constraint in the efforts to promote slm approaches. first, poverty which has already been perceived as an underlying cause of land degradation in uganda is sustained by external and internal forces such as declining soil fertility and productivity of land, vulnerability to climate variability especially persistent droughts and other natural calamities, epidemic diseases, unskilled human capital due to low education levels and poor health due to debilitation diseases such as malaria and hiv/aids. poverty in uganda is also hinged upon inadequate possession of land resources, access to credit and financial resources and poor physical infrastructure such as markets and roads (matagi, 2002). with limited livelihood alternatives, it is difficult for farmers/pastoralists to adopt good land management practices, some of which seem to take long before benefits can be realized. in the rangelands, pastoralists resist livestock destocking recommendations due to their preoccupation with risk management during drought periods and also due to cattle rustling. agricultural and pastoral households also maintain a large family size as insurance for constant source of human labor and security for old age. the censuses of 1980, 1991 and 2002 put the population in uganda at 12.6 million, 16.1 million and 26 million, respectively. in barely two decades, the population in uganda had doubled. since 1991, the uganda bureau of statistics (ubos) estimated that, the average rate of annual increase has been around 2.5% despite the hiv/aids infection rates which have profoundly affected demographic patterns (ubos, 2006). this rate of growth is expected to continue and it is predicted that it will reach 55 million by 2025. these and other social factors significantly are likely to lower the rate of adoption of slm practices in uganda. policies and strategic frameworks uganda has a comprehensive set of policy, strategies and action plans to address the issues of land degradation. however, these initiatives have not been very effective in reversing the land degradation trends. the country lacks the resources, both technical and financial, to tackle the issues of slm within the environmental management and coordination act. as such, some of the national strategic frameworks formulated are discussed. national strategic frameworks and slm approach the poverty eradication action plan (peap) poverty incidence in uganda is closely linked to land degradation problems (akello, 2002; nkonya et al., 2002; wood, 2002) and it could be the main obstacle in addressing land degradation, since resources are required for investing in good land management practices. in 1995, uganda started a process of developing a comprehensive and sustainable development strategy, with an overall objective of wiping out abject poverty in the country. this process culminated in the formulation in 1997 of the peap, which aims at reducing the population living in absolute poverty to 10% in 2017. in 2000 this was revised to incorporate information generated from the widened consultations and analysis, particularly, from the pilot participatory poverty assessments. based on the peap as the guiding policy framework, uganda has pursued the development and implementation of sector-wide policies, investment plans and programmes, with the participation of as many stakeholders as possible. as such, two strategic action plan frameworks are discussed. the nap/united nations convention for combating desertification framework the nap is an integral part of the national economic and social development and environment protection plans. the united nations convention for combating desertification (unccd) calls for the formulation and implementation of nap as the central element in a strategy to combat desertification/land degradation and to mitigate the effects of drought. under the national unccd framework, the government of uganda had made several efforts that included entrenching nap priorities within the main national development frameworks such as the peap, and efforts to mainstream nap into the various sectoral plans and programmes. the environment and natural resources sector, which is a key to nap implementation, has also been centrally positioned and recognized in the peap. the capacity of nap to address land degradation in the country and especially in dry lands is hampered by low capacity. the plan for modernization of agriculture (pma) the pma focuses on agricultural modernization and commercialization through a multi-sectoral approach to addressing the constraints facing agricultural-based livelihoods. interventions in the pma included research and technology development, advisory services, rural financial services, rural infrastructure, sustainable national resource use and management. basically, pma seeks to promote sustainable use and management of the environment and natural resources. since the pma is seen as a broad strategy within the framework of peap, the harmonization of approaches among all the keys stakeholders in the peap with the pma is critical and lacking at this stage due to limitations of technical and financial resources. environment and natural resources policy frameworks and slm approach land policy the government of uganda has formulated a land sector strategic plan (lssp) for the period ranging from 2001 to 2011, to be implemented in two phases. the key issues of sustainable land management addressed by lssp are; ownership and management of reserved land (forest reserves, national parks, wildlife reserves, lakes, rivers and wetlands) under the trusteeship of government/local government, management of common property resources, individual land use and planning and development of urban areas. lssp acknowledges that, there is a lack of a holistic, clear land use policy and national and district physical development plans. the implementation of lssp has been constrained by among other factors, the delay in approval of the land act amendments, funding (timing and predictability of flow of funds) and political insecurity and instability (akello, 2002). the smooth implementation of lssp assumes all areas in the country are accessible. the insecurity and instability in the northern and north-eastern districts of the country has undermined the initiative. the land act also lacks a clear policy on equitable access to land among family members and hence, development of land policy, land-use policy and land sector laws are being addressed in the lssp. the rate of implementing land reforms aimed at preventing land degradation and also creating an enabling policy environment for the adoption of sustainable land management practices is slow and not well synchronized with the expected pace of implementing national sustainable development plans. only 15% of the national land is registered under mailo, freehold and leasehold. hence, the most serious challenge to introducing slm is insecurity of land tenure. the process of land titling and certification is expensive (us $250 at the minimum) and therefore, remains a long term objective. slm should experiment with pilot areas in the various land tenure systems to see if the positive results of slm can catalyze the process of land demarcation and definition of land ownership and landuse rights. for this challenge to be overcome there is a need to build the capacity at national, district and country levels for the establishment of land information system that will support and inform national land and land-use policies and also serve the needs of other stakeholders. environmental policy the government of uganda has developed the national environment action plan (neap) to provide a framework for addressing environment and natural resource management concerns. the national environment management authority (nema) established by the national environment act (2000), is the leading organ of the neap and oversees natural resources management. the neap/nema implementation process over the past two years had emphasized capacity building for environment management at the district and lower levels. although, the efforts by neap/nema for institutional capacity building are commendable, there is a need to formulate environmental checklists at all levels (national, district, and local/community), to monitor development activities in compliance with national sustainable development policies. one major weakness of environmental and natural resources legal frameworks is the weak capacity for enforcement and implementation. though several institutional reforms have been made, the review of associated laws has been too slow, making implementation of laws rather difficult especially in cases where environment enforcement officers have had to deal with high profile politicians. forest policy the national forestry plan (nfp) formulated in 2003 seeks to increase incomes and quality of life of poor people, increase economic productivity, employment in forest industries and achieve sustainable resource management in the central forests. the plan recognizes the need to integrate with nap/unccd framework for combating land degradation. however, nfp falls short of specifying the linkages with the nap framework and also with pma. the plan will draw on the private sector to promote sustainable forest management practices. rangeland management policy although, rangelands cover 43% of uganda and support over 6 million people, there is no coherent rangeland policy that addresses the broad range of environmental issues such as land tenure, immigration of people from densely populated areas, privatization of land along the north east south west cattle corridor and expansion of crop cultivation into rangelands. the policy also does not clearly safeguard the land rights of pastoralists to avoid conflicts over privatization of common property rights. the current initiative to review and formulate a new rangeland management policy is an opportunity for addressing the current driving and underlying forces that are responsible for land degradation. other land-related policies relevant to land degradation and slm although, not discussed in detail, several other sectoral policies and strategies that are likely to influence slm implementation exists in uganda and they include; national food security strategy, national wetlands policy, national water action plan, national biodiversity strategy and action plan. ongoing slm initiatives some of the key ongoing slm initiatives are described as; kagera transboundary agro-ecosystem management it is a multi-focal project addressing land degradation, biodiversity and climate change with relevance to international waters. a key aspect of the project relevant to slm is the creation of a communication and education strategy to share and disseminate the best practices in uganda, burundi, tanzania, rwanda and democratic republic of congo (d.r congo). integrated nutrient management to attain sustainable productivity increases in east african farming systems this project addresses the serious decline in soil fertility and crop productivity in smallholder farms in uganda through institutional strengthening for farm or catchment level technologies, strengthening the policy to address soil nutrient depletion and the generation and dissemination of appropriate soil fertility management technologies. lake victoria environmental management project (lvemp) this project covers uganda, kenya and tanzania and it is aimed at supporting the governments through harmonization of legislation for environment and strengthening the policy and institutional capacities for biodiversity conservation. development strategy and investment plan by the ministry of agriculture, animal industry and fisheries (maaif) the development strategy and investment plan has identified several intervention areas relevant to slm such as capacity building for water harvesting, soil and water conservation, agricultural research and technology, agricultural planning and policy and agricultural advisory/extension service through naads. payment for environmental services (pes) this is a good practice and has proved to be a good approach in scaling up slm. pes initiatives are common for water, biodiversity and carbon/forest projects. cases in focus include the agreement between local communities and uganda wildlife authority for park management, payment for ecotourism services in parks and sanctuaries and planting trees for global carbon benefits. uganda shares important natural resources with the neighboring countries, which calls for inter-country and trans-national cooperation and policy harmonization. an illustration of a national park will suffice. a national park lies in the virunga mountains in the eastern d.r congo and then, borders rwanda and rwenzori mountains in uganda. interestingly, in each of the three countries, the national park has a different name. in d.r congo, it is known as virunga national park while in rwanda, it is national park and in uganda, rwenzori national park. covering 7,800 km 2 , it was established in 1925 as africa's first national park and world's second to yellowstone (united states of america). intensive poaching and the civil wars in the respective three countries seriously damaged its wildlife population and the capacity to monitor and control activities therein in the recent past. land invasions had also challenged the park authorities in the three countries. widespread depletion of forest due to fuel-wood demand by refugees had also impacted the park negatively. in addition, cross border conflicts have had a toll on slm initiatives. uganda has been at the center of conflicts, both internal and external and so civil/political/ethnic tensions are common in uganda and some neighboring countries such as sudan, d.r. congo, kenya and rwanda. cattle rustling and fighting (karamoja of uganda/pokots of kenya) over pasture and water resources is also a pertinent issue. in this paper some transboundary and regional conventions and agreements are discussed as follows: transboundary and regional conventions and agreements past and present regional activities, conventions and agreements that impacted the policy framework in place include: the lake victoria fisheries convention of 1994 which aims at regulating and enhancing fisheries on lake victoria. the lake victoria basin is threatened by overgrazing, poor crop cultivation, removal of vegetation cover (matagi, 2002), water quality degradation (cowi, 1998; emerton et al., 1999; okwerede et al., 2005), uncontrolled development along the lake shore and river banks and industrial waste (banadda et al., 2009). currently, lake victoria environment management project discussed in the preceding section is being implemented by uganda, kenya and tanzania to arrest land degradation and water quality deterioration; the kagera basin agreement of 1977 whose objective is to ensure equitable entitlement of each riparian state to the use of the river nile waters. the kagera river basin occupies a strategic position in africa providing up to 10% of the water of the downstream nile basin and forms the upper part 75% of the lake victoria basin. the lower kagera river basin confers a set of global biodiversity benefits which are now threatened by rapid population pressures, land-use changes and associated land degradation as a result of deforestation and encroachment of wetlands. in uganda, of the nakivubo wetland (the largest) original area of 5.29 km², it was estimated that, 2.9 km² of nakivubo remains uncovered (cow and vki, 1998) and thus, 2.39 km² or 45% had been modified or reclaimed. the consequences of this encroachment on the wetlands contributing negatively to water quality in the lake victoria and on the ecological balance is fairly well documented (cowi and vki, 1998; okwerede et al., 2005; banadda et al., 2009). clearing forests and wetlands for agriculture is taking place in parts of burundi, d.r. congo, uganda and rwanda. the present forest cover in uganda is estimated at about 3.6%, which is about 20% of its original value in 1890, as a result of deforestation (maaif, 2004). it is therefore of paramount importance that land degradation initiatives should bear transboundary characteristics for slm. response options and recommendations for slm mainstreaming at multiple levels although, uganda has a comprehensive set of policy strategies and action plans to address the issues of land degradation, these initiatives have not been very effective in reversing the land degradation trends. as such, strategic choices to address identified gaps and barriers associated with the constraints discussed earlier are described. institutional and governance strategic choices strengthen national development/institutional frameworks there is a need to harmonize slm initiative with the existing initiatives particularly under united nations convention for combating desertification (unccd)national action programmes (nap) framework. in addition, slm approach may be introduced through the focal national institutions that are mandated with the implementation of comprehensive africa agriculture development programme (caadp). this should be harmonized with nap since slm approach is aimed at preventing land degradation and maintaining sustainable agriculture. there is need for coordination of activities within nap framework for effective and efficient resource utilization targeting sustainable land management. the nap structure is linked to the local and sub-regional initiatives to combat land degradation and is therefore the most ideal mechanism of linking sub-regional and international slm initiatives. support land and land-use policies issues of access to land and land tenure security are critical in the plan to modernize agriculture for economic growth and poverty reduction. the plan to establish a land information system is an important aspect of slm approach particularly for the decision makers at all levels. such a plan is to go hand in hand with the necessary political support for the enforcement of land related laws. mainstreaming slm at sub-regional and regional levels slm practices have been highlighted in the new partnership for african development (nepad)-caadp country programmes, which provide a good entry point for coalition of development partners to contribute technical and financial resources at sub-regional and regional levels. economic and financial strategic choices financial and technical support for the decentralization of responsibilities to district and local institutions establishment and support of environmental services need to be reflected in the budget allocation. this approach will facilitate compensation mechanisms for investment in high cost practices such as soil and water conservation measures. integration of poverty strategic programme with slm approach this strategy addresses economic and financial incentives that will support livelihoods dependent on natural resources and agricultural/rural development. the national economic recovery strategy is largely based on the pma policy which supports the sustainable agriculture and management of natural resources. a fair share of pma resources are expected to support slm practices. budgetary support for slm approach according to the maputo (mozambique) declaration of 2002, the ugandan government is expected to raise support of agriculture to 10% of the national budget. this target is yet to be achieved. initiatives should continue catalyzing slm mainstreaming and funding through coalition of partners since national commitment in cofinancing slm activities are likely to be constrained by other macro-economic considerations. the nap process/mechanism should ensure uganda's national desertification fund and community development fund to support the slm approach. technological and knowledge choices the lessons from integrated area-based development activities in east africa are relevant in the introduction of slm approaches. at the community level, strong emphasis on facilitating farmer-to-farmer information sharing and technology transfer have been effective in farmers' field schools experiences in east africa (fao, 2002). policy and institutional reforms are required for enhancing the participatory technology development and for effective dissemination mechanisms that take cognizance of decentralized governance framework. some of the technology transfer priorities are discussed further. support sustainable agricultural practices that conserve natural resources promotion of conservation agriculture (ca) is strongly recommended for its unique contribution to slm. the ca approach embraces researcher-extension-farmer linkage for up-scaling slm practices. soil nutrient management and fertility ongoing activities entail controlling soil erosion problems, use of organic/farm and green manure, use of cover crops and introduction of nitrogen fixing plants. irrigation and water management promotion of water lifting technologies, water harvesting, rehabilitation of smallholder irrigation schemes and national capacity for sustainable smallholder irrigation technologies may be a win to win situation where food security and livelihood support goes hand in hand with sustainable land management. rangeland management and livestock management given the high vulnerability of dry land ecosystems from human-induced land degradation, preventive, restoration and control measures are critical investment areas. investment in land-use planning is an effective strategy to minimize negative environmental impacts from ad hoc settlements and encroachment of cultivations in key production areas. other potential areas of investment in sustainable rangeland management include: policy reforms to define land tenure and community property rights; participatory community land use planning; investment in natural resources-based conflict resolution mechanisms; protection of wetlands key production areas against conversion to agriculture; livestock productivity improvement and rationalized water development activities; development of livestock marketing infrastructure to facilitate livestock off-take to control overstocking and overgrazing problems. social and behavioral choices investment in farmer education and extension service is the most effective way of dealing with social and behavioral change. the empowerment of farmer organizations, community based organizations (cbos) and non-governmental organizations with information on slm are one major way of changing the mindset of land users. the participation of religious institutions is critical in educating land users on good land stewardship principles in accordance with the accepted moral norms. the integration of slm activities with peap and pma will ensure that, these national development frameworks are responsive to slm concerns. the slm approach should be relevant and acceptable to small-scale farmers who are subsisting on 36% of uganda land area. investment in strengthening governance/leadership of community based organizations to deal with issues of conflict management, education and community health needs is also necessary. conclusion in this work, the major human induced types of land degradation in uganda which include soil erosion, soil fertility decline and habitat loss were discussed the outcomes and experiences of past sustainable land management initiatives in uganda have brought out various lessons worth noting, which include a key lesson learnt in promoting conservation which is, unless farmers can expect an economic return equal to their level of investment, there will be little incentive for them to adopt sustainable land management practices. another lesson learnt was that, participatory approaches to land management involving stakeholder greatly contribute to sustainable productivity and conservation of land. it is prudent to support greater involvement of farmers and other stakeholders in participatory technology development and transfer. in conclusion the success of some identified best practices in dealing with the problem of land degradation has been anchored on these facts; their contribution to household incomes, threading partnerships, collaboration and synergies dialogue and institutionalization of key breakthroughs, availability of markets for products, cost effectiveness of operations and bottom-up participatory process. acknowledgement the author is thankful to the interuniversity council of east africa (icuea) 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issn 2375-0707 vol. 10 (1), pp. 001-011, january, 2022. available online at www.internationalscholarsjournals.org © international scholars journals author(s) retain the copyright of this article. full length research paper when ecological functions are more important than richness: a conservation approach vagner santiago do vale*, ivan schiavini, ana paula de oliveira and andré eduardo gusson laboratory of plant ecology, federal university of uberlandia (campus umuarama), cep: 38 400-902, uberlândia mg, brazil. accepted 7 october, 2021 in this work, we utilize the assessment of functional groups (fg) and functional diversity (fd) to evaluate and compare the ecological functions of two types of dry forest of south eastern brazil. hence, we hypothesized that forests with different species richness could have similar fd and fg, but distinct ecological functions. the floristic composition from two physiognomies (deciduous and semideciduous forests) of six tree communities was carried out in the state of minas gerais, southeastern brazil. the inventory was pooled together considering the traits of species such as: shade tolerance, deciduousness and desiccation tolerance of seeds; one structural feature: position on vertical strata; and two animal-plant interactions: dispersal syndrome and pollination syndrome. we chose two multivariate analyses to infer to the functional groups and used the one-way anova to test differences between the abundance of the groups in the two physiognomies. the difference in fd between the two physiognomies was tested using the shannon diversity index and the hutcheson ttest. both physiognomies had the same fg and fd. the most abundant group in the semi-deciduous forest was g1, which occupied lower communities (shade tolerant and perennial), whereas g4 for deciduous forest was anemochoric and autochoric of superior community strata that is light demanding. the functional diversity between the two physiognomies showed that semi-deciduous contains more species than the deciduous ones (75% more species) and are more diverse with the shannon index of 3.3. hence, the number of species alone had little importance when we analysed functions in ecosystems. the more abundant groups in each forest had completely different traits and were complementary in their functions to the ecosystem. in this case, a species-rich and lessspeciesrich system provided different key functions to the ecosystem despite their differences in species richness, diversity or physiognomic type. the use of species-rich and lessspeciesrich areas would present different key groups, and as such, this may be the best alternative to choose priority areas for conservation. key words: complementarity, deciduous forest, dry forest, functional diversity, functional groups, semideciduous forest. introduction the classification of functional groups (fgs) reduces a large number of species in a small group of functional types, which incorporate the same responses to perturbations or are similar with regard to dispersion, competition and survival processes (hubbell, 2005; skov, 2000). groups of species may also reveal features of *corresponding author. e-mail: vsvale@hotmail.com. system functionality (swaine and whitmore, 1988) which would be difficult to detect when looking at the species separately. the use of fgs is particularly important because the diversity of functional types is more important than the diversity of species for many aspects of ecosystem performance (pendry et al., 2007) . for example, plant reproductive success tends to increase with the functional diversity of pollinators (fontaine et al., 2006). additionally, functional diversity increase plant 2 productivity and light penetration in a grassland-savanna, but species diversity does not (tilman et al., 1997). thus, functional diversity (fd) can be defined as a variety of life-history traits presented by an assemblage of organisms (fontaine et al., 2006; mayfield et al., 2005) and it is critical for the maintenance of ecosystem processes and properties (tilman et al., 1997). the usual measure of fd is the number of functional groups in a community (hooper and vitousek, 1997; tilman et al., 1997) and the number of species and traits that influence the functional groups (petchey and gaston, 2002b, 2006). a greater number of traits and species are associated with more functional groups and, therefore, more fd (petchey, 2004; petchey and gaston, 2002a), although this is not always true. however, a greater number of species does not necessarily mean more traits (petchey and gaston, 2002a) or more fd and fg. hence, we hypothesize that forests with differences in species richness could have similar fd and fg, but distinct ecological functions in the ecosystem. for a good representation of ecological functions, we need to choose traits that represent important functions to systems. most studies on functional diversity in plant communities have focused on the importance of traits associated with plant physiology, like sunlight interception or shadow tolerance (girao et al., 2007). little is still known with regards to the functional diversity of traits that affect ecosystem functioning, such as those related to plantanimal interactions (fontaine et al., 2006; mayfield et al., 2005), mainly on the tropical ecosystems with high diversity and complex interactions. therefore, studies which associate plant physiology and plant-animal interactions are needed to better understand and compare forest systems. to test the hypothesis we used a brazilian seasonally dry tropical forest, one of the most threatened ecosystems in brazil (espirito-santo et al., 2009). also, dry forests are neglected by research and conservation efforts compared to the tropical rain forests (sanchezazofeifa et al., 2005), maybe because they lower the diversity of plant species on the seasonal forests. dry forests can be subdivided into seasonal deciduous and semi-deciduous forests (oliveira-filho and ratter, 2002). both are physiognomically identical in terms of structural parameters (height of canopy, density and basal area) and appear next to each other or are connected in the landscape, but the first one is less rich in species. however, we know little about the ecological functions in the ecosystem of these threatened forests, and as such, comparisons of ecological functions in similar physiognomic environments are still lacking. we aimed to answer the following questions to test our hypothesis: (1) can less-species-rich forests have similar functional diversities as compared to species-rich forests? (2) are the functional groups of these forests similar? (3) do similar functional groups have the same value of the ecosystem? (4) can the functional diversity in complementary forests justify different conservation efforts? methods the study was conducted in six fragments of seasonal forests in the state of minas gerais, south-eastern brazil at coordinates 18°56’ s and 48°12’ w, 18°40’ s and 48°24’ w, 18°29' s and 48°22' w for semideciduous sites and 18°48’ s and 48°07’ w, 18°47’ s and 48°06’ w, 18°39’s and 48°25’ w for deciduous sites. the sites were in the same climatic zone, characterized by warm temperatures throughout the year with a rainy summer and a dry winter. the regional climate is aw (tropical savannic) according to the köppen classification (1948), with a mean annual precipitation of 228.5 mm in each wet month (october to march) and 35.5 mm in each dry month (april to september), and a mean annual temperature of 23.7°c available in a weather station called the 5° meteorological district/uberlândia station, brazil. a plant species list for three seasonal deciduous and three semi-deciduous sites was collected in arboreal community studies (kilca et al., 2009; siqueira et al., 2009; vale et al., 2009). an area of one hectare was sampled at each site and all trees, with a circumference at breast height (cbh to 1.3 m above ground floor), that are equal to or larger than 15 cm were measured. only species with at least five individuals in each site were analysed. the data of the three deciduous sites were united as one sample and the same was done with the data for the three semi-deciduous sites. for each species, data were collected for three physiological traits: (1) shade tolerance, (2) deciduousness and (3) desiccation tolerance of seeds; one structural feature: (4) position on vertical strata; and two animal-plant interactions: (5) dispersal syndrome and (6) pollination syndrome. these characteristics are illustrated in table 1. information about these ecological attributes were researched in scientific articles and specialist books, field observations, specialist conferences and the analyses previously performed on the structure of tree communities (table 1) . a total of 53 species in the deciduous forest and 93 species in the semideciduous forest were analysed. the complete list of species, with the occurrence, density, matrix of treats and group is shown in appendix 1. the same species found in both forests were considered once in the matrix. therefore, a matrix with 132 species and 19 traits (table 1 and appendix 1) was used for analysis. we converted the data into a presence/absence matrix with species and their ecological attributes. the columns were exclusive for each characteristic. following this, a matrix of ecological distance was produced (petchey and gaston, 2002b). the functional groups were derived by the distance matrix, using the “cluster” and the “correspondence” analyses. cluster analysis the groups were defined by euclidian distance and a dendrogram generated through the group average (upgma). multivariate clustering methods were used to see which groups of plant species would emerge. these methods calculated the similarity or association measures based on the extent to which species have attributes in common (leishman and westoby, 1992). the cophenetic correlation for the generated dendrogram was calculated. the coefficient of cophenetic correlation (equivalent to the pearson coefficient) was proposed as a measure of how a dendrogram maintains the original pair wise distances (bussab and morettin, 1990). the statistical analyses were performed using the fitopac shell 1.6.4 program (shepherd, 2004). correspondence analysis (ca) this exploratory technique could represent the correspondence 3 table 1. characteristics and their respective ecological functions used for the distance ecological matrix. trait classification categories ecological function dispersion syndrome diaspores dispersed by wind anemochory long dispersion, which is affected slightly by fragmentation. free fall or ballistic mechanisms autochorory short distance dispersion, highly affected by fragmentation. birds ornitochory medium distance of dispersion, affected by fragmentation and a resource for birds. mammals mammaliochory short distance dispersion, highly affected by fragmentation and a resource for mammals. deciduousness species were all leaves fall off during some period of the dry station deciduous high litter release and canopy opened to other plants. remain during the entire year perennials shade and refuge for animals, increases shading to other plants. shadow tolerance light environment required for establishment tolerate shade under other trees shade tolerant low growing species and climax species, related to maturity of forest. need direct sunlight to develop light demanding fast growing species, generally represent initial stages of regeneration. vertical strata based on the stature commonly reached by adult individuals always reaches the canopy typical canopy represents greater biomass accumulation and shades smaller species. sometimes, it reaches the canopy intermediate strata integrate canopy and understory, generally representing some strata. usually do not reach the upper layers of the typical understory low basal area but high density species, is a distinct habitat forest for animals than canopy. seed desiccation related to how seeds remain in the environment tolerance until the next season seeds are able to survive until the next season orthodox form seed banks in forest. seeds are unable to survive until the next non-orthodox form a "bank of seedlings" but not a seed bank season 4 vale et al. 273 table 1. contd. pollination syndrome species were classified by animal pollinator body size under 5 mm very small insects prevent inbreeding, promotes genetic variability and a resource to very small insects. small bees, wasps and flies (body size 5-12 mm) small insects prevent inbreeding, promotes genetic variability and a resource to bees, wasps and flies. bees with large size body (more than 12 mm) large bees prevent inbreeding, promotes genetic variability and a resource to big, solitary bees. beetles beetles prevent inbreeding, promotes genetic variability and a resource to beetles. butterflies and moths lepidoptera prevent inbreeding, promotes genetic variability and a resource to moths and butterflies. bats bats prevent inbreeding, promotes genetic variability and a resource to bats. between species. we considered this technique appropriate for detecting functional groups because the ecological distance between the species is expressed graphically. this analysis was performed using fitopac shell 1.6.4 program (shepherd, 2004). to compare the functional diversity, we calculated shannon diversity index (brower et al., 1997) for the functional groups that is resultant from the cluster and correspondence analysis. unlike the traditional shannon index, the abundance of species is replaced by abundance of groups. therefore we treat the shannon index value for functional groups like functional diversity. then we calculated and compared the significance of these indices with hutcheson t-test for the deciduous and semideciduous forests (brower et al., 1997). one-way anova was used to test differences in the abundance of groups between deciduous and semideciduous forests, and to test differences in group species number per plot. for these tests, we randomly selected 50 plots in the deciduous and semi-deciduous forests. the bonferroni post-hoc procedure was applied to assess differences in group abundance among the sites. abundance data were transformed into a logarithmic scale (base 10) for data standardization. the intention of these analyses was to determine if the areas with lower species richness and diversity have priority for conservation and if these criteria are valid for dry forests. we think that these methods, using fd and fg, could help in prioritizing conservation by focusing on ecosystem functionality. results the 53 tree species analysed here represented 92% of the individuals found in the deciduous sites. the 93 tree species analysed in semideciduous sites represented 91% of the total of individuals in this physiognomy. these high values indicate the high representation of species analysed in these systems. appendix i shows the list of species used for the analysis of functional groups with the number of individuals and the respective attributes of each one. the dendrogram formed five groups (figure 1) with a high cophenetic correlation of 0.77, thus the dendrogram and species ecological differentiation showed a good correlation. therefore the number of functional groups is the same for both forests (five). the hutcheson t-test for the shannon index value found between forests for the five groups was not significant (p > 0.1; df > 500). this means that these forests have the same functional diversity. however, in the correspondence analysis of ecological distances, we could only view four cohesive groups. this was because two of the groups formed in the dendrogram (g3a and g3b) were joined together in the ca (figure 2). all four groups contained deciduous and semideciduous species. therefore, the fg found in both analyses was strictly the same. the hutcheson t-test for the shannon index value found between the four groups in ca was not significant (p > 0.1; df > 500). this means that these forests have the same functional diversity for ca groups too, just like cluster analyses. after it was found that there were no great differences between both multivariate techniques, we concluded that both techniques were satisfactory for showing fg in forests. as there were no major ecological differences between groups g3a and g3b in the cluster analysis, hence we chose to use the results of the ca for the remainder of the analysis. table 2 shows the ecological characteristics of the four groups found 5 figure 1. functional groups based on ecological distance formed by clustering in six seasonal dry tropical forests in southeastern brazil. a cluster was defined by the euclidian distance and upgma method. group characteristics are shown in table 2. in the semi-deciduous and deciduous forests. the abundance (number of individuals in each group) of the four groups varied between the forests. g1 was the most abundant group in semi-deciduous forests, while g4 was the most abundant in deciduous forests (figure 3a), but both groups had the same abundance according to the bonferroni test (p > 0.05; df = 7). the five other groups showed no significant differences for abundance. the bonferroni test showed that g1d, g3d, g3s, g2d and g4s had the same weight to ecosystem in terms of the number of individuals (p > 0.05; df = 7) (d is for deciduous and s is for semi-deciduous forest). one group (g2s species on lower layers of the community is shade tolerant, deciduous, ornitochoric and pollinated by small insects and lepidoptera) was underrepresented in the semi-deciduous forest. these results reflect the environmental differences between both forests. as such, deciduous forests have more water deficit in soil during the dry season (oliveira-filho and ratter, 2002), which influences the deciduousness in these sites. however, this feature of water stress in soil clearly separated the two physiognomies, not only due to the deciduousness which interferes with floristic and structural variations, but also in the main functions of these forests (compares g1 and g4 in table 2). unlike the abundance, the number of species per group showed different results. the two most species-rich groups were the same as the most abundant groups for the forests (g1s and g4d figure 3b). however, the other groups were significantly different according to the bonferroni test. group g4s had more species than the remaining five groups and g3s had more species than the other remaining four groups (p < 0.01; df = 7). therefore, these four groups (g1s, g4d, g4s and g3s) were more redundant in the ecosystem than the others were. as such, the remaining groups had the same number of species (p > 0.05; df = 7). these results show that the number of species do not always have a relation with the abundance of the groups formed. g3 has the same abundance for both deciduous and semi-deciduous forests (figure 3a), but is much richer in the species on semi-deciduous forest (figure 3b). the inverse occur in g2, with same richness (figure 3b), but more abundant on deciduous sites (figure 3a). when analysing the similar groups for both forests, we could see differences for groups per physiognomy. for example, g1 had more species and individuals in the semi-deciduous forest than in the deciduous forest (figures 3a and 3b), and g4 was more abundant in the deciduous forest (p < 0.01; df = 7), but the number of species in both physiognomies was the same (p > 0.05; df = 7). group g3 had the same number of individuals (p > 0.05; df = 7) in both forests, but the species number was much greater in the semi-deciduous forest (p < 0.01; df = 7) . finally, g2 was more abundant in the deciduous forest (p < 0.01; df = 7), but the species number was the same in both physiognomies (p > 0.1; df = 7). this means that functional groups may have a greater influence on the floristic composition or structure in forests, depending on soil moisture. in the deciduous forest (drier) there was a greater variation in forest structure than in the number of species (greater abundance of g2 and g4 figure 3a, but no variation in the number of species in these groups figure 3b). furthermore, the semi-deciduous forest was more rich in species (g3 figure 3b), but there was no variation in the abundance of this group (g3 figure 3a). discussion can less-species-rich forests have similar functional diversities to species-rich forests? seasonal dry tropical forests (deciduous and semideciduous) are present in all tropical regions, but mainly in the neotropics (miles et al., 2006). deciduous forests are more associated with a water deficit in the dry season and are less rich in species (oliveira-filho and ratter, 2002; ratter, 1992). however, the functional diversity, or 6 -0.3 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5 -0.45 -0.4 -0.35 -0.25 -0.2 -0.15 -0.1 -0.05 eixo 1 (65.21%) figure 2. functional groups based on ecological distance formed by correspondence analysis in six seasonal dry tropical forests in south-eastern brazil. the black circles represent semi-deciduous species, the empty circles represent deciduous species and the grey circles represent species common to both physiognomies. the black solid lines show group 1, the grey solid lines denote group 2, the grey dotted lines denote group 3 and the black dotted lines show group 4. however, group characteristics are shown in table 2. table 2. functional groups formed by correspondence and cluster analysis and their respective characteristics for six seasonal dry forests in minas gerais, brazil. functional main determinant characteristics of the functional groups groups group 1 (g1) occupies lower layers of the community and is shade tolerant and perennial. provides fruit resources to birds. the pollination is performed by small insects, lepidoptera and very small insects. there are non-orthodox seeds. group 2 (g2) occupies lower layers of the community and is shade tolerant. unlike g1, it is deciduous. this group provides fruit resources to birds. the pollination is performed by small insects and lepidoptera. there is no distinction in tolerance of desiccation of seeds. group 3 (g3) this is a zoochoric group from higher layers providing resources to mammals and birds. this group is perennial and has shade-tolerant and light-demanding species. the greatest diversification of pollinators occurs in this group (small insects, very small insects, moths, butterflies and beetles). most species are non-orthodox. group 4 (g4) this is the only group that is abiotically dispersed (anemochoric and autochoric) and is fully deciduous. it occupies the superior community strata and is light demanding. this is the only group pollinated by large bees, but is still pollinated by small insects and lepidoptera. most species in this group are orthodox. 7 2.0 1.5 1.0 0.5 0.0 figure 3. one-way analysis of variance for the log number of individuals “a” and number of species “b” per group (g1, g2, g3 and g4) for deciduous (d) and semi-deciduous (s) seasonal dry tropical forests with the bonferroni post-hoc test. the same letters denote that there is no statistical difference and the different letters represent significant differences. the black points represent the means and the lines represent standard deviations. the extent of functional differences among the species in a community (tilman et al., 2001), could be the same in deciduous forests as in semi-deciduous ones, despite their difference in species richness. our results exemplified this. semi-deciduous forests contain more species than the deciduous ones (75% more species) and are more diverse (the shannon index for semideciduous forests is above 3.3 and less than 2.8 in deciduous forests) (kilca et al., 2009; siqueira et al., 2009; vale et al., 2009), but both have the same fd (four) as shown by the study’s results. hence, the number of species alone has little importance when analysing functions in ecosystems. other studies demonstrated fd having a greater impact on ecosystem processes than species diversity (tilman et al., 1997) and addressing questions about ecosystem processes (chapin et al., 2000; diaz et al., 2001; tilman et al., 2001). in some systems, a decrease in species richness can even lead to an increase in functional richness/diversity, increasing the number of ecosystem processes (loreau et al., 2001; micheli and halpern, 2005). thereby, less-species-rich systems could present similar fd to species-rich systems and both are important to ecosystem maintenance. here, deciduous forest (a less rich system) has the same fd than semi-deciduous forest (a richer system). thus we cannot neglect systems with lower species richness because, for some ecological attributes, they present the same number of functions systems with greater species richness. many conservations efforts focus more on species-rich systems. however, we have demonstrated that systems with lower species richness could posses the same number of functions as species-rich systems, therefore having the same ecological importance. are the functional groups of these forests similar? the functional groups in both forests were exactly the same in the attributes that were analysed. this was because the species in the deciduous forest had the same ecological functions than semi-deciduous species, even though there were fewer species. however, the number of species per group and number of individuals per group greatly varied. this could be observed in g1 and even more clearly in g3. g1 was more abundant and much richer in species in the semi-deciduous forest, while g3 was equally abundant in both forests but was much richer in species in the semi-deciduous forest. this variation in species richness between these forests could be important when considering the ecological redundancy of the species in a group. this is particularly important because a greater number of species with similar characteristics represents a greater ecological redundancy (walker et al., 1999). the higher the redundancy, the lower the chance of one species’ loss, resulting in the loss of a function to the ecosystem (micheli and halpern, 2005). many species in a group represents more species capable of occupying the niche of a species affected by a perturbation (loreau, 2000; walker, 1992). if a rare species becomes extinct, this can be compensated by the growth of a similar dominant species (smith and knapp, 2003). in the case of a low redundancy, the loss of a species with a determinate 8 functional trait could have a great impact on the community, and the reverse is also true (micheli and halpern, 2005). in deciduous forests, some characteristics are more dangerous because fewer species do these functions (like g3). the study areas are in a threatened seasonal biome, in the brazilian savannas (cerrado) (myers et al., 2000). during the dry season in the savannas, the forests could be an important refuge for animals, particularly vertebrate dispersers. a greater number of plant species represents a greater capacity for maintaining vertebrate species (mainly for birds and mammals in this case) in the case of a disturbance. species with ecological redundancy could not have the same tolerance to disturbance (micheli and halpern, 2005; walker et al., 1999), and in deciduous forests, few species are available as resources for vertebrates. here, climate changes may affect the high abundance of species which cannot be replaced by others with the same function. this could cause serious problems in supplying food to the animals in these forests and therefore alter the environmental relationships and functions. do similar functional groups have the same value in the ecosystem? despite the four groups being found in both physiognomies, the abundance of the groups or the value of each group in the ecosystem was clearly different. when the abundance of g1 and g4 are compared, it can be suggested that the major groups were different in both forests. whilst these forests had the same fd, they had different weights for each group in the ecosystem and therefore distinct functions in the environment. this is very important because these two physiognomies are considered as the same “dry forest” in the literature. however, we demonstrated that these forests are complementary because they have different functions for the ecosystem. semi-deciduous forests (dominated by g1) have more vertebrate resources. birds and mammals have the preference to occupy different layers of the forest (clark et al., 2001; pearson, 1971). this preference could be linked to temperature, leaf density, luminosity and abundance of resources (pearson, 1971; richards, 1996; walther, 2002; walther et al., 1999). more perennials of lower strata groups like g1 could provide a different luminosity and temperature for vertebrates than the canopy. in this case, the vertebrates that forage in the canopy should be distinct than those that forage in the understory. group g3, for example, had the same abundance in deciduous and semi-deciduous species, but it is a canopy group and should have the same function in both forests. therefore the importance of g1 for the diversity of large animals, particularly those that forage in the understory, is a clear function to the ecosystem. this group also produces non-orthodox seeds. nonorthodox seeds are linked to fresh fruit (tweddle et al., 2003); therefore, g1 can provide constant shade and protection against insolation and also provide fresh fruit to animals in lower layers of vegetation. pollinators do not respond clearly in groups because they do not form specific groups. nevertheless, we highlighted the presence of very small insects that are only found in the understory species of g1. these pollinators contrast with the large bees found only in the canopy species (g4), demonstrating niche differentiation for pollinators in these forests. on the other hand, the deciduous forest (dominated by g4) could be considered as less affected by fragmentation processes because it is abiotically dispersed. the dispersion efficiency in superior strata is generally greater in anemochoric than zoocoric species (clark et al., 2001) and species with a high dispersal capacity are less susceptible to fragmentation processes (fahrig and merriam, 1994; frankie et al., 1974; lord and norton, 1990). light demanding species, such as those in g4, can easily attain higher layers of communities having distinct colonization processes compared to g1. the occurrence of a group with tall heights dominating the deciduous forest is due to the diaspore dispersal distance increasing with plant height in wind dispersal (deng et al., 2008; howe and smallwood, 1982; wikander, 1984; yamamoto et al., 2007), and deciduousness is related to this syndrome because leaves could hinder the dispersion. the orthodox seed of this group also provides the chance to form a seed bank for future seasons. deciduous forests could not even lose leaves, but twigs too (dry branches that fall from trees). species which spend their lifetime under a closed canopy have more chances of being hit by debris (deng et al., 2008). this could be a factor that favours the abundance of a higher group in a deciduous forest (g4) over the understory groups. the chance of a deciduous canopy recruit (g4 species) being hit by debris is small because deciduous species generally grow faster than perennials (cornelissen et al., 1996) and live in fewer understory areas. also, light demanding species grow faster than shadow tolerant (poorter and bongers, 2006) species and the g4 abundance indicated that deciduous forests can accumulate more biomass and recover faster after perturbation events. on the other hand, the lower abundance of g4 species provided by the perennial canopy in the semi-deciduous forest could facilitate the presence of shadowtolerant plants in the lower layers of a community. shade tolerant species are more persistent in the environment because they have more protection against herbivores, less mechanical disturbance due to the greater wood density (chave et al., 2006; coley, 1983; poorter et al., 2006; swenson and enquist, 2007) and they can provide a more stable understory in the semi-deciduous forest. 9 figure 4. fluxogram showing the steps in this work. note that both forests, one with high species diversity and one with lower species diversity, are important to conservation. when two types of forest occur in the same environment, both need to be conserved to prevent the loss of ecological functions. can the functional diversity in both complementary forests justify different conservation efforts? we argue that the socalled "dry forests" have different ecosystem functions. these forests are commonly classified according to the degree of deciduousness (veloso et al., 1991; scariot and sevilha, 2005; oliveirafilho and ratter, 2002). however, we think that semideciduous and deciduous forests have distinct traits and therefore distinct functions to the environment. greater differences between species trait values represent greater trait complementarity independent of the number of species (petchey and gaston, 2002b). species complementarity is related to species that occupy distinct spatial niches and thereby fulfil complementary functional roles (loreau, 2000). in the present study, the species rich and not too species rich “dry forest” had key functional groups with distinct traits. here, deciduous forests have mainly group g4 and semi-deciduous have mainly group g1. these groups are different too, in terms of their functions to the ecosystem and the forest. the first one is a canopy light demanding deciduous abiotically dispersed group (g4) and the other is an understory shade-tolerant perenial animal dispersed group (g1) (figure 4). furthermore, these forests are complementary in terms of functions. it is shown that the functions performed by one type of forest were not performed as often in the other type, hence the more abundant groups in these forests (g1 and g4) are distinct in several key features of a forest or even in an ecosystem. from a wider view of both types of forest co-occurring in the cerrado biome, the deciduous forest is considered as less species rich and the semi-deciduous forest is considered as species rich (oliveira-filho and ratter, 2002). we think that the co-occurrence of a species rich and less species rich system could provide different key functions to an ecosystem and that both can be very complementary despite differences in species richness, diversity or physiognomic type. at least, this seems to be true for the dry forest. the functional group diversity is an important determinant of ecosystem functioning for some locations, but not for others (petchey, 2004), and functional groups do not represent the same value to an ecosystem due to the differences in abundance of groups. for the dry forest, the most important factor is the abundance of key 10 functional groups and thus their complementarity for the ecosystem (figure 4). some papers have shown the importance of complementarity (loreau, 2000; petchey and gaston, 2002b) and we think this should be analysed in more detail to show its real importance to a system. in this work, deciduous and semi-deciduous forest is shown to be complementary (g1 and g4 differences in table 2), so both forests are important for ecosystem in different ways despite their species richness. henceforth, we should think in terms of a system rather than the kind of forest, number of species or species diversity alone, but we should also think in terms of the functions that a determinate area could provide for all “microsystems” existing there. on a broader scale, we can argue that less-species -rich systems, when cooccurring with systems of greater species richness, could provide different services to ecosystems and we need to pay more attention to this fact when determining conservations areas (figure 4). the use of species rich and less-species-rich areas would present different key groups or high complementarity and may be the best alternative we have for choosing priority areas for conservation. acknowledgments the authors acknowledge the fundação de amparo à pesquisa do estado de minas gerais (fapemig cra 0694/08) for financial support and the capes agency for fellowship to vagner s. do vale. also, they express their gratitude to two anonymous reviewers for their thoughtful and detailed comments on the manuscript. references brower 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author(s) retain the copyright of this article. full length research paper impact of wood cuts on the structure and floristic diversity of vegetation in the peri-urban zone of ngaoundere, cameroon tchobsala1*, amougou akoa2 and mbolo marie2 1 faculty of sciences, university of ngaoundere, box 454, cameroon. 2 faculty of sciences, university of yaounde, box 812, cameroon. accepted september, 2021 the main objective of this paper was to study the impact of various wood cuts on the structure and the floristic diversity of the savannas, and to seek for durable solutions against deforestation during a four year investigation. an inventory of the woody layer on 120 sites areas of 50 × 50 m showed that savannas have structures in "l". this structure translate the state of the degradation of the vegetation. the floristic diversity showed that the characteristic species of the degradation of the shrubby savannas area are hymenocardia acida, piliostigma thonningii and annona senegalensis, and those of the wooded savannas are daniellia oliveri and cesalpinia sp. it was also shown that highest wood cuts are depressive for the stability of the savannas and for the disappearance of the vegetable biodiversity. consequently, they are responsible for the acceleration of the degradation and the alarming installation of the desert in wet savannas of ngaoundéré. a measure of co-administration between the government and the bordering population must be therefore encouraged to protect and safeguard the anthropized vegetation. key words: wood cuts, structure, floristic diversity, degradation, reconstitution, cameroon. introduction the impact of wood cuts on african savannas became increasingly extensive since a quarter century, accelerating therefore the degradation of the natural resources (ndjidda, 2001). the satellite pictures of occupied grounds in the the wet savannas of the adamaoua’s region in cameroon showed that the surface passed from 120 ha in 1951 to 1256 ha in 2001, that is, a mean rate of increase of 22 ha per year. this surface would be 1454 ha in 2010 by extrapolation. the surface of shrubby savannas decreased approximately 10.8% compared to the year 1951 due to the creation of vast fields of corn production in the north of ngaoundéré; a major city located in that region, the appearance of a significant agriculture in the south of the city, the plantations of the corn mill company occupying 1548 ha. the galleries *corresponding author. e-mail: tchobsala2002@yahoo.fr. tel: 74248541/96050865. along the roads and near villages are the most cut by the population (tchotsoua, 2006). their surfaces passed from 1844 to 784 ha between 1951 and 2001; that is, a reduction of more than 50%. rippstein (1985), yonkeu (1993) and tchotsoua (2005) worked on the degradation of the wet savannas of adamaoua by overgrazing, overpopulation, agriculture, and exploitation of woods for cooking by the local population. in north cameroon, ntoupka (1994, 1998) investigated the regression of the forest by the combined effects of wood cuts, bush fire and overgrazing. mbolo (2005), zapfack (2005), guedje (2002) and sonké (1998) worked on the impact of wood cuts on the structure and floristic diversity in south cameroon’s vegetation. these studies showed that wood cuts significantly affect the structure and floristic diversity of vegetation. but in the wet savannas of ngaoundéré, no work is yet carried out on the impact of wood cuts on the structure and floristic diversity of the vegetation, except that of chouaibou (2006) who worked on the structure of parkia biglobosa 2 in the district of ngaoundéré. however that area is among those seriously threatened by anthropic activities (wood cuts, bush fire, overgrazing, etc.). this study will be devoted to the impact of different wood cuts on the structure and floristic diversity of vegatation in general, and specifically to the modification of the structure of the vegetation, floristic diversity, and methods of conservation of the vegetables. description of the study area the study was conducted in the subdivision of ngaoundéré including ten villages namely: béka hooseré, wakwa, tizon, beskewal, ngaohora, borongo, dang, onaref, darang and mbangmboum (figure 1). the choice of these villages was related to their proximity to the capital of the adamaoua region (ngaoundéré), and to the regional weather station. they are located in an aureole of approximately 900 m² around ngaoundéré (7°14'n, 13°34'e) except mbang-mboum, located some 60 km far away. in 2001, the population of ngaoundéré was approximately 230 000 inhabitants, with a rate of increase of 2.81% (tchotsoua, 2006). the main activities are breeding and agriculture. more than 53% of the rural population practises traditional agriculture of subsistence (millet, cassava, sorghum, potato, corn, yam, groundnut, tomato, etc). the area, however knew an industrial crop in the years 1970 with the creation of some agroalimentary firms. the grounds are characterized by sedimentary, volcanic, granitic, and metamorphic rocks, including: tropical ferruginous ferralitic grounds (humbel, 1971); modal slightly ferralitic grounds (martin and segalens, 1966); luvisol and ferrisol, telvic or acrisols and nitosols grounds which develop on old basalts and occupy the major part of the plate; typical strongly unsaturated grounds with pseudo particles; altered ferralitic grounds; mineral rough grounds (lithosols and rankers) (humbel, 1971); etc. the vegetation of the region of adamaoua corresponds to a typical soudano-guinean sector with an active aspect from shrubby to raised savannas. these savannas are dominated by daniellia oliveri and lophira lanceolata (létouzey, 1968, 1986), species that are prolific with the favour of the zooanthropic factors like farming fires, pastures and clearings. in the fallow and around the villages, this formation has the same aspect with an herbaceous layer dominated by many andropogoneas (hyparrhenia spp., andropogon spp. …) and paniceas (panicum spp....) which can reach at the end of the vegetative cycle up to 2 to 3 m in these zones. abundant precipitations occur between june and august, and are null from november to february. the atmospheric relative humidity is maximum in august with a monthly average of 81.38%. the maximum monthly average for the rainy season varies from 68.32% (april) to 81.8% (august) while the minimal for season is between 3.12% (february) and 6.3% (november). the population mainly uses hymenocardia acida, piliostigma thonningii, terminalia glaucescens, guineense syzygium spp, l. lanceolata, harungana madagascariensis and annona senegalensis etc, as cooking energy, terminalia macroptera, terminalia glaucscens, lophira lanceolata and sysygium guineenses var macrocarpum etc for coal, vitellaria paradoxa, tamarindus indica, syzygium guineense, ximenia americana as comestible wild fruits (tchosoua et al., 2000 and mapongmetsem, 2005), piliostigma thonningii as forage for the ruminants during dry seasons (tchobsala, 2003), d. oliveri, t. glaucescens, t. will macroptera, terminalia laxiflora and uapaca togoesis for wood service, and d. oliveri and x. americana for bee-keeping. materials and methods choice of the different wood cuts in the savannas to determine the degree of wood cuts, the method of “quadrants centered on a point" was used. 200 plants were therefore chosen on areas of 2500 m² and the sites grouped according to their degrees of wood cuts. sequences from 0 to 10%; 11 to 25%; 26 to 50%, and 51 to 100% were retained for the study. the choice of sites took into account the access to the wooden resource and the distance from the village (0 to 0.5 km; 0.5 to 1 km; 1 to 2 km; 2 to 4 km; 4 to 6 km and > 6 km). percentages of wood cuts permitted to determine four types of wood cuts (treatments) in the peri-urban zone of ngaoundéré are: 1. pilot or witness cuts (t0): made up with natural formation where the percentage of wood cuts is less or equal to 10%. these are generally protected areas. 2. weak cuts (t1): vegetation where the percentage of wood cuts is between 11 and 25%. 3. average cuts (t2): where the percentage of wood cuts is between 26 and 50%. 4. complete or total cuts (t3): vegetation where more than 50% of woods are cut. experimental device the experimental device installed in 2004 was a split-study with 3 factors (shrubby savannas, raised savannas and wooded savannas) (table 1). the pieces were numbered from 1 to 12, delimitated by numbered cement terminals or wood stakes. 30 sites were selected for each treatment; that is 120 sites in total (3 types of savannas × 4 types of cuts × 10 villages). a compass was used for a good orientation on the study area methods of data collection and analysis of vegetation the heights and diameters of the vegetation were measured by a team of five persons: the pointer, three assistants and a guide who plays the role of coordinator and monitor. the team sweeps each tailboard of 50 × 50 m one after the other. the species are identified in local language by the guides and thereafter compared to those of the herbaria of wakwa (adamaoua) and the schools of fauna of garoua and yaounde. the species that were not identified in these herbaria are sent in the national museum of natural history of the institution smithsonian and missouri botanical garden in the united states of america. the readings of the vertical stratification were taken in the 3 figure 1. study area. 4 table 1. experimental device. n° bes beka ona bor wak tiz nga dar dan mba 1 sat3 sat3 sat2 sat3 sct0 sat0 sat3 sbt0 sct1 sct0 2 sat2 sat2 sat3 sct3 sct3 sat1 sat2 sat0 sct2 sat0 3 sct3 sat0 sct0 sbt1 sct2 sat2 sat1 sat1 sct3 sbt0 4 sct2 sct0 sct3 sct2 sbt1 sat0 sat0 sct0 sct0 sbt2 5 sbt1 sbt3 sat0 sat1 sbt0 sbt1 sbt0 sat2 sat0 sbt3 6 sbt3 sbt2 sbt0 sbt0 sbt2 sbt0 sbt2 sat3 sat2 sbt1 7 sbt0 sbt0 sbt3 sbt3 sat1 sbt3 sbt1 sct3 sat1 sat3 8 sat0 sct1 sbt1 sct0 sat2 sbt3 sbt3 sbt3 sat3 sat2 9 sct0 sct3 sct1 sat0 sat0 sct3 sct3 sbt2 sbt3 sat1 10 sat1 sct2 sct2 sct1 sbt3 sct2 sct2 sbt1 sbt0 sct3 11 sbt2 sat1 sbt2 sat2 sat3 sct1 sbt1 sct2 sbt2 sct2 12 sct1 sbt1 sat1 sbt2 sct1 sct0 sct0 sct1 sbt1 sct1 bes: beskewal; bek: beka; ona: onaref; bor: borongo; wak: wakwa; tiz: tizon; nga: ngaouhoura; dar: darang; dan: dang; mba: mbang-mboum; sa: shrubby savannas; sb: raised savannas; sc: wooded savannas. heights’ sequences of: 0-50 cm; 50-130 cm; 130-200 cm; 200-400 cm; 400-600 cm; 600-800 cm; 800-1000 cm; 1000-1200 cm; 12001400 cm; 1400-1600 cm; 1600-1800 cm, 1800-2000 cm, 2000-2500 cm and >2500 cm. the measurements of the horizontal stratification related to the diameters of the trees were taken according to the following sequences: 0-5 cm; 5-10 cm; 10-15 cm; 15-20 cm; 20-25 cm; 25-30 cm; 30-35 cm; 35-40 cm; 40-50 cm; 50 60 cm; 60-80 cm; 80-100c m; 100-120 cm, 120-150 cm, 150-200 cm, 200-250 cm and > 250 cm. the heights were measured on all alive and cut species on areas of 50 x 50 m² according to a cross or linear transect in each village. for highest trees with more than two meters, a clinometer was used. the numbers of cut and alive trees were taken to evaluate the death rate of the flora per unit of area. measurements of the circumferences at heights of 1.30 cm were taken to evaluate the cut susceptibility of the species. the woody cover of each species was measured starting from the surface of projection of the foliages on the ground using a decametre. the measurements of natural regeneration were taken on the seedlings heights less or equal to 50 cm from the ground in the rainy season (tchobsala, 2003). the analysis of the results was done by several methods: 1. the profile of stratification suggested by amougou (1986) for tropical areas was adopted: a. layer a or higher arborescent layer, made up with very high trees (35 m and more); b. layer b or average arborescent layer, whose heigths are between 25-35 m, forming a more or less continuous and dense canopea; c. layer c or lower arborescent layer, constituted with 15-25 m heights trees; d. the layer d or shrubby layer, made up with small trees and shrubs less than 15 m height. for these arborescent layers, it was necessary to add the herbaceous layer or layer e which can reach 3 m height, constituted of epiphytes and lianas. the combination of these 4 layers offers 15 types of stratification with a single possibility of complete stratification, 4 possibilities with 3 layers, 6 to 2 layers and 4 mono-stratified possibilities. moreover, each one of these layers can be subdivided into sub-layers which are indicated from the top to the bottom by numbers 1, 2 and 3 affected by letters indicating the layers. for example, a sub-layer d can be presented as follows: d1: 10-15 m, small trees; d2: 5-10 m, shrubs; d3: 5 m and less, shrubs or suffruteux. 2. richness of the settlement: it corresponds to the relationship between the number of individuals and species; 3. the index of diversity of shannon (1949) in legendre and legendre (1984) is given by: ish = ∑(ni/n) log2 (ni/n) where ni is the number of species i and n the total number of the species. 3. equitability (eq) of piélou in frontier and pichod-viale (1993) is given by: eq = ish/log2n. it corresponds to the relationship between the observed diversity and the maximum possible diversity of the number of species n. 4. the index of diversity of simpon is given by: d = 1/∑ (ni/n) 2 (begon et al., 1987) or simply d = ∑ (ni/n) 2 (colinvaux cit.sonké, 1998). 5. the absolute density (ni) of a taxon corresponds to the total number of the stems of this taxon per unit of area. 6. the relative density (dr.) is the relationship between the number of individuals of a species and the total number of individuals of all the species met on an area multiplied by 100. 7. terrian surface (st) of species i is the sum of the terrian surfaces of all representant of the species. 8. the relative predominance (pr.) of species i is the ratio of its terrian surface to the total terrian surface of the settlement 10. the absolute frequency (f) of species i is the number of statement containing this species. 11. the relative frequency is the number of the statements containing this species to the total number of the statements multiplied by 100. according to braunblanquet (1932), the indices 5 table 2. indices of relative frequency. symbols indices type of death i 020 accidental species ii 21-40 additional species iii 41-60 rather frequent species iv 61-80 frequent species v 81-100 very frequent species table 3. delimitation of the layers according to the maximum diameter reached. categories of species diameter category arborescent species large (wooded savannas) averages (raised savannas) small (raised savannas) shrubby species large (shrubby savanna) averages (shrubby savanna) small (shrubby savanna) 100 cm exceed a ranging between 50 and 100 cm b ranging between 20 and 50 cm c ranging between 10 and 20 cm d ranging between 3 and 10 cm e ranging between 0 and 3 cm f of this frequency is summarized in table 2. the delimitation of the layers was made on the basis of maximum diameter reached (table 3), using the scale of letouzey (1986) and volter (1993), and making some modifications to the various categories of species. the species were classified in two groups (arborescent and shrubby) and, various categories were retained within these groups. 12. the principal phytogeographical types are those admitted for africa (lebrun, 1947). the recognized types are the species with broad geographical distribution including: a. cosmopolitans (cos): species found throughout the whole world; b. pantropicales (pan): species known in africa; c. tropical-american and asian; d. afro american (aa): species extended in tropical africa and america; e. paleotropical (pal): species present in africa and tropical asia, madagascar and australia; f. afromalgaches (am): species common to the islands of madagascan and central african areas; g. multi-regional african (pra): species whose surface of distribution covers several floristic african areas or two floristic areas which are not in contact. we also have guineean and soudano zambezian species (g-sz) species including: a. sub-omni guineo-congolese (gc): species presented in all the floristic guinean area; b. central (cg): species whose surface of distribution goes from cameroon to the democratic republic of congo; c. western guineans (wg): species which are widespread of western africa in western cameroon; d. cameroon-congo (caco): species only found in the cameroonian solid mass and the congolese basin; e. cameroon-gabon (ca-gab): known species only of the forest solid mass cameroon-gabon-mayumbe. f. cameroon (camwood): species only found in cameroon. 13. according to lebrun (1947), the biological type of a species is the whole of the anatomical and morphological devices which characterize its vegetative apparatus and make conspicuous its habitat and its aspect independently to its systematic position and adaptation to the environmental conditions. biological types according to the classification of raunkiaer (1934), adapted to the tropical areas by schnell (1971) are: a. phanerophytes including: i. megaphanerophytes (mgph), whose heights are around 30 m; ii. mesophanerophytes (msph), whose heights range between 10 to 30 m; iii. microphanerophytes (mcph) , whose heights range between 2 to 10 m; iv. nanophanerophytes (nnph), shrubs with heigths under 0.4 to 2 m. v. phaneorophytes lianescents (phgrv. phgr); voluble plants with gimlets, cramps roots, crawling or supported; vi. phaneorophytes epiphytes (phep). b. chameophyts (ch): i. chameophytes drawn up (chd); ii. chameophytes prostrate (chpr); iii. chameophytes crawling (chrp); iv. chameophytes climbing (chgr); c. geophytes (g): plants whose persistent growths or buds are sheltered in the ground during the bad season: i. rhizomateux geophytes (grh); ii. tuberaux geophytes (gb); iii. geophytes climbing (ggr); iv. geophytes epiphytes (gep). d. hemicryptophytes (h): plants which the growths are located at the short-nap cloth of the ground: * cespiteux hemicryhytes (hce). 6 1600 1400 -1 1200 o fs t e m s .h a 1000 800 n u m b e r 600 400 200 0 shrubby savanna raised savanna wooded savanna 0-50 200-400 800-1000 1600-1800 > 2500 heights (cm) figure 2. structure of the population according to the size of the trees. e. theophytes (th): annual plants or at very short growing period, deprived of persistent buds themselves and whose survival is ensured by seeds, they include: i. theophytes drawn up (thd); ii. theophytes prostrate (thpr); iii. théophytes scapeux (thsc). f. hydrophytes (hy); watery plants. in this work, we interested only to the megaphanerophytes, mesophanerophytes and microphanerophytes. trees which have less than 10 cm diameter to height of the chest were exclusively inventoried. 14. the types of dissemination of diaspores were given according to the classification of dansereau and lems (1957). the various types are: a. pterochores (ptéro): small diaspores with aliform appendices; b. pogonochores (pogo): diaspores with feathery or silky appendices; c. slerochores (scléro): not fleshy and relatively light diaspores; d. sarcochores (sarco): diaspores completely or partially fleshy; e. desmochores (desmo): diaspores hanging or adhesive; f. ballochores (ballo): diaspores expelled by the same plants; g. barrochores (baro): not fleshy diaspores; h. pleochores (pleo): small diapores with a floating appendix. 15. statbox version 6.40 was used for the factorial analysis of the principal components (acp) of the structure of the vegetation. results structure of the vegetation according to the various types of vegetable formations the structure of the vegetation as a function of the types of savannas is presented in figure 2. it is seen that in general, cut savannas have structures in "l", materialized by a great number of minor stems and little adult stems. such a structure generally presents a good arborescent regeneration after wood cuts. the curve of tendency presents an equation of the form y = -2601.2 x + 25300 with a coefficient of correlation of 0.5249. the number of the stems is more significant in shrubby savannas with vegetables’ heights between 0 and 200 cm. in the three types of formations, there is a reduction in the number of stems when the size of trees increases. from 200 cm the number of stems is almost null. structure of savannas according to the various types of wood cuts the structure of the vegetation in the treatments t0, t1, t2 and t3 is presented in figure 3. it can be seen that in some type of savannas, the number of stems is significant between 0 and 200 cm (t0). shrubby and wooded savannas are more representative in the number of stems. raised savannas are richer in stems of vegetables with heights between 0 and 130 cm for the treatment t1. the number of the stems decreases when the heights of the trees increase. from 200 cm, the number of the stems becomes null. in fairly cut savannas (t2), the trees have more significant stems in wooded savannas where trees’ heights are between 0 and 130 cm while highly cut savannas (t3) present less stems. from 200 cm, few trees are found. in general, the vegetation consists in young plants resulting from the regeneration of the cut trees. it is at the level of shrubby savannas that the number of rejections is significant impact of wood cuts on the evolution of the structure of savannas from 2004 to 2006 the structure of the vegetation from 2004 and 2006 presented a light regressive evolution (figure 4). the 7 500 400 (a) 350 (b) 400 300 300 250 200 200 150 100 100 0 50 1600-1800 0 0-50 200-400 800-1000 classes of heights of stems ha -1 in cm 0-50 200-400 800-1000 1600-1800 classes of heights of stems ha -1 in cm n u m b e r o f s te m s h a -1 800 600 -1 700 h a 500 (d) (c) of st em s 600 400 500 300 n u m b e r 400 200 300 200 100 100 0 0 >2500 0-50 400-600 1200-1400 0-50 200-400 800-1000 1600-1800 >2500 classes of heights of stems ha -1 -1 classes of heights of stems ha (cm) shrubby savanna raised savanna wooded savanna figure 3. structure of savannas according to the cuts: (a), weak (b), average (c) and strong (d). 4500 -1 4000 h a st e m s 3500 3000 of th e 2000 2004 2006 d e n s it y 2500 1500 a bs ol ut e 1000 >2500 500 130-200 400-600 800-1000 1200-1400 0 0-50 1800-2000 figure 4. evolution of the vertical structure of the vegetation of 2004 to 2006. number of the stems decreased gradually from 2004 to 2006. this translates the regression of the wet savannas of ngaoundéré. the curve of evolution of the stems by hectare decreased brutally from the heights 0 50 cm to 400 600 cm. from 600 up to 2500 cm, the curve is superimposed on the x-coordinate. it can be seen from the graph that the structure of the heights is represented by the curve in "l ". diametric structure of the ligneous family the classes of trees with diameters from 0 to 10 and 10 to 20 cm present highest number of stems (figure 5). in 8 n u m b e r o f s te m s / h a 60000 50000 shrubby savanna 40000 raised savanna 30000 wooded savanna 20000 10000 0 010-20 30-40 50-60 70-80 90-100 110-120130-140 170-180 190 classes of diameters in cm figure 5. diametric structure of the ligneous family in savannas of the cuts. 2d graph 2 25000 20000 15000 d a ta 10000 y 5000 0 t0a t1a t2a t3a t0b t1b t2b t3b t0c t1c t2c t3c x data plot 1 figure 6. diametric structure of the ligneous family as a function of various wood cuts. t0a: treatment t0 shrubby savanna;t1a treatment t1 shrubby savanna; t2a treatment t2 shrubby savanna; t3a treatment t3 shrubby savanna; t0b treatment t0 raised savanna; t1b treatment t1 raised savanna; t2b treatment t2 raised savanna; t3b treatment t3 raised savanna; t0c treatment t0 wooded savanna; t1c treatment t1 wooded savanna; t2c treatment t2 wooded savanna; t3c treatment t3 wooded savanna these classes, highest number of rejects are found. diametric structure of the vegetation according to the various wood cuts the treatment t0a presents the greatest number of the individuals, followed by t1a and t2a. the others are almost equal in density of individuals (figure 6). the analysis of principal component (acp) shows that the values of pearson are significant (except diagonal) for the threshold alpha = 0.05 (bilateral test). this shows that the structure of the vegetation varies according to the classes of the diameters of the stems. the highest average is for 9 table 4. average and standard deviations of the diametric structure of the woody state. classes of diameters in cm average standard deviations 0-10 a 10735.50 5348.62 10-20 b 9592.75 2637.72 20-30 c 3902.75 2527.11 30-40 d 796.67 245.51 40-50 e 218.25 90.32 50-60 f 76.67 44.18 60-70 g 43.67 30.81 70-80 i 28.17 21.95 80-90 j 28.50 22.40 90-100 k 6.58 5.87 100-110 l 2.83 2.85 110-120 m 1.50 1.98 120-130 n 1.58 2.33 130-140 q 2.75 6.03 140-150 u 3.08 6.49 150-160 s 3.75 9.57 160-170 v 1.83 3.34 170-180 w 0.58 0.86 180-190 x 0.42 0.76 190 -200 y 0.42 1.11 >200 z 0.33 0.62 the class of diameters between 0-10 cm (10735.50 stemsha -1 year -1 ) with a standard deviation equals to 5348.62. the lowest average is obtained for the class of diameters greater than 200 cm (table 4). the analysis of the principal variables component, according to the axes f1 and f2 shows a variation of 57% in the classes of diameters (figure 7). the classes a, b and c are under the axis, the others are gathered around similar values (variable (axes f1 and f3) 53%, variables (axes f1 and f4) 46%, variables (axes f2 and f3) 38%, variables (axes f2 and f4) 31%, variables (axes f and f4) 27%). classification of the species according to the maximum diameter the species were classified depending on the diameters reached. in the wet savannas of ngaoundéré, a great number of stems has diameters between 0-10 cm (table 5). h. acida, h. madagascariensis, p. thonningii, annona senegalinsis etc are mainly found. the density of these stems decreases as the diameter increases. when the diameter is beyond 100 cm, there is no stem in the shrubby savannas. in addition, the density remains significant for wooded savannas and form forest galleries of high trees. in this class, d. oliveri, cesalpinia sp., z. guiennese var. guinense, t. glaucescens, l. lanceolata, etc. are found. influence of wood cuts on the survival and the biological state of the species as a function of each type of vegetable formation figure 8 presents the effects of wood cuts on the density of alive and dead stems in the three types of vegetable formations. in the shrubby savannas, treatment t1 presents the greatest number of alive stems, while much of cut stems are found in t3. in raised savannas, the number of the cut stems is more significant. however, the numbers of cut stems are approximately the same in the four treatments. in wooded savannas, the numbers of alive stems are approximately the same for t0 and t2. they are relatively less in t1 and t3. the number of the cut stems is very weak for the whole treatments. influence of various types of wood cuts on the biological state of the vegetation figure 9 summarizes the impact of the wood cuts on the density of the stems as a function of the treatments. for the treatment t0, the density of alive stems is significant in the shrubby and wooded savannas, but it is less in raised savannas. the numbers of cut stems decrease in 10 variables (axes f3 and f4 : 27%) variables (axes f1 and f2 : 57%) -a x e f 4 ( 1 0 % ) 1.5 1 c 0.5 b d a i fge sq v x z 0 u w y j m n -0.5 l k -1 -1.5 -1.5 -1 -0.5 0 0.5 1 1.5 a --axe f3 (17%) -a x e f 2 ( 2 1 % ) 1.5 1 s uq v 0.5 g 0 i f j e ldk a b c y w x -0.5 znm -1 -1.5 -1.5 -1 -0.5 0 0.5 1 b --axe f1 (36%) figure 7. variation between the classes of diameters of the vegetation of ngaoundéré. table 5. classification of the species according to the diameters reached. diameter (cm) categories shrubby savanna raised savanna wooded savanna 0-10 e et f 1852 1256 1186 10-20 d 1430 1247 1160 20-50 c 736 490 741 50-100 b 6 30 138 >100 a 0 10 76 the shrubby and wooded savannas. they are very weak in protected savannas, showing that in the protected savannas, the activity from the exploitation of wood resources is controlled. for slightly cut savannas (t1), the number of alive stems is relatively significant in raised savannas. for the treatment t2, the number of alive stems is very high in wooded savannas. treatment t3 presents a great number of alive and cut stems. this number falls when one passes from shrubby to wooded savannas. impact of wood cuts on the evolution of the density of species from 2004 to 2006 the vegetation is mainly made up of shrubs e.g h. acida, p. thonningii and h. madagascariensis which respectively had absolute densities of 3077, 1025 and 1542 stems.ha 1 in 2004; and 2907, 949 and 1511 stems.ha -1 in 2006. the relative densities of these species were respectively 27.63, 9.21 and 6.021% in 2004. in 2006, there was a light reduction in the relative density: 27.53, 8.99 and 6.023% respectively, for these species. the difference between the relative densities of these species is not too perceptible because of their speed of regeneration. these three species clearly colonize shrubby savannas. species like h. madagascariensis, t. glaucescens and d. oliveri having relative densities of 13.851, 5.516 and 5.421% in 2004 are forest species with affinity to ngaoundéré’s region. their relative densities also slightly increased in 2006, respectively 14.340, 5.746 and 6.670%. they are more present in the forest galleries or wooded and raised savannas. indeed, the species with forest affinity have a high capacity of regeneration towards threats. impact of the wood cuts on the floristic composition and the density of the species 140 species, 60 kinds, 34 families, and 371 alive stems.ha -1 year -1 were averagely identified in 2004 and 11 (a) -1 h a 900 s te m s 800 700 c u t 600 o r 500 a liv e 400 300 o f 200 n u m b e r 100 0 t0 t1 t2 t3 (b) 1 n u m b e r o f a liv e o r c u t s te m s h a t1 t2 t3 t0 type of the wood cuts type of the wood cuts alive stems cut stems (c) 1200 1000 800 600 400 alive stems cut stems 200 0 t0 t1 t2 t3 type of wood cuts figure 8. density of the stems alive and cut in shrubby savannas (a), raised (b) and wooded (c). 351 stems.ha -1 in 2006. the evolution of the specific density of the vegetation (table 6) shows that the species which do not tolerate the wood cuts such as t. indica, securidaca longepedunculata and strychnos spinosa are disappearing in the savannas. in 2006, 13 new species appeared in the sites of study. this is the case of erythrophleum guinneensis, heeria pulcherima and nuxia congesta. on the other hand, 25 species disappeared in 2006. among them t. indica, combretum sp. and croton sp. it could be noted that much of the species lost their density from 2004 to 2006 e.g. h. acida (170 stems.ha 1 year -1 ), p. thonningii (76 stems.ha -1 year -1 ), a. senegalensis (35 stems.ha -1 year -1 ) and h. madagascariensis (30 stems.ha -1 year -1 ). other species gained in density during these three years. among them d. oliveri, allophyllus africanus and pachira aquatica. these results show that the degree of drageonment or the rejections of these species is very significant. dynamics of the natural regeneration of the species according to savannas in the whole thirty hectares inventoried, shrubby savannas presented the highest capacity of regeneration (figure 10). raised and wooded savannas appreciably have the same densities of rejections per hectare. the average density of the rejections is 3712.45 stems.ha -1 for individuals with circumference lower than 3 cm, and 1423.41 stems.ha -1 for the individuals with circumference greater than 3 cm. influences of wood cuts on natural regeneration regeneration is more significant for the treatment t0 12 (a) density of the stems according to the witness cuts (t0) 1200 1 h a 1000 stems8 00 o f 600 number s200 400 0 shrubby raised wooded savanna savanna savanna types of savannas (b) density of the stems according to the weak cuts (t1) 1000 1 h a 800 of s te m s 400 600 n um be rs 0 200 shrubby raised savanna savanna wooded savanna types of savannas (c) density of the stems according to average cuts (t2) h a 1200 st e m s 1000 o f 800 1 n um be r s 600 400 200 0 shrubby raised wooded savanna savanna savanna type of savannas cut stems (d) density of the stems according to the -1 high cuts (t3) h a 1600 st e m s 1400 1200 o f 1000 1 n u m be rs 800 200 600 400 0 e shrubby raised wooded savanna savanna savanna type of savannas alive stems figure 9. density of the stems according to the cuts: witness (a), weak (b), average (c) and high. n u m b e r o f re g e n e ra te d s te m s . h a -1 2000 1500 1000 500 0 height shrubby raised wooded savanna savanna savanna figure 10. density of the seedlings according to savannas. -1 (391.933 stems.ha ) with a standard deviation of -1 181.2306 stems.ha (table 7). evolution of the rejections after wood cuts the heights and the diameters of the seedlings were measured each year on pieces of 10 × 10 m cut at the level of the ground in order to study the dynamics of these species. it was observed that, some species integrated the parcel and others disappeared due to the pressure of the wood cuts. the height of each stem was measured each year during three years. during the first year, each rejection was marked, this made possible to evaluate the mortality of the stems. the mortality of the seedlings is in majority due to the activities of the 13 table 6. absolute density (stems ha -1 ) and relative and profit or loss of the ligneous family of the species (en %). absolute relative absolute relative absolute relative absolute relative scientifics names density density density density scientifics names density density density density 2004 2006 2006 2004 2006 2006 acacia polyacantha 14.47 0.13 12.47 0.12 v. paradoxa 16.42 0 9.17 0 acacia siberiana 0.47 0 0.07 0 commiphora kerstengii 1.23 0.01 1.01 0 afzelia africana 7.3 0 6.17 0 cordia africana 0.12 0 0.1 0.01 albizia chevalieri 0.83 0.01 0.8 0.01 cordia myxa 0.01 0.01 0 0.02 albizia coriaria 12.65 0.11 9.63 0.09 cordia sinensis 0.63 13.85 0.61 14.34 albizia lebbeck 4.63 0.04 4.63 0.04 corianga sp 0.93 0.01 1.23 0.01 albizia zygia 17.85 0.16 15.9 0.15 crossopteryx febrifuga 0.14 0.83 0 0.83 albizia adianthifolia 4.53 0.12 3.53 0.1 croton macrostachys 92.18 0.01 88 0.01 alchornea laxiflora 1.29 0 1.2 0 c. zambesicus 0.03 0.03 0.03 0.03 allophyllus sp 46.55 0.42 66.47 0.63 cussonia africanus 0 0 0 0 a. africanus 106.38 0.96 126.37 1.2 cussonia barteri 40.65 0 39.83 0 ancylobotrys amoena 0.07 0.14 0 0.13 d. oliveri 603.53 0.37 703.21 0.38 andira inermis 0.07 0 0.03 0 ekebergia senegalensis 8.5 5.42 9.5 6.67 a. senegalensis 670.48 6.02 635 6.02 entada africana 312.67 0.08 300.5 0.09 berlinia grandiflora 0.34 0 0 0 erythrina senegalensis 3.11 0.29 3.07 0.23 boswelia sp 0.11 0 0 0 erythrina sigmoidea 235.4 0.02 213.14 0.02 bridelia ferruginea 155.12 1.39 150.23 1.42 erythrophlium guinense 238.48 2.81 2.5 2.85 bridelia ndelensis 0.33 0 0.13 0 espèces undeterminées 1.97 0.02 1.01 0.01 burkea africanus 13.13 0.01 10.13 0.02 eugenia nigerina 0.77 2.11 0.13 2.02 carissa edulis 8.17 0.06 1.2 0 ficus capreafolia 0.02 0.02 0 0.01 carissa spanarum 13.5 0.07 10.5 0.01 ficus vogelii 1.32 0.04 0.5 0.03 cinera machrostachys 68.31 0 60.1 0 ficus glumosa 28.85 0 18.53 0 citrus sp 0.04 0.61 0.03 0.57 ficus vallis-choudae 0.87 0.19 0.57 0.19 clausena anisata 1.17 0 1.11 0 ficus platiphylla 1.03 0 0 0 combretum glutinosum 1.1 0.01 0.12 0.01 ficus sp. 0.55 0.01 0.43 0 combretum micrantha 26.05 0.02 25.9 0.01 ficus sur 1.34 0.26 0.1 0.18 combretum nigricans 0.02 0.07 0 0.06 ficus sycomorus 8.43 0.01 8.3 0 combretum molle 243.04 0.36 239.89 0.36 ficus thonningii 2.25 0.01 1.13 0.01 combretum lecardii 1.2 0.01 0 0 ficus trichopoda 0.01 0 0.17 0 flacourtia sp 0.13 0 0.13 0 flacourtia indica 12.53 0.08 9.41 0.08 flacourtia vogelii 0.07 0.01 0.02 0 ochna scheinfurthii 9.21 0.04 8.23 0.04 flueggea virosa 0 0.75 0.02 0.78 oncoba spinosa 2.07 0.47 1.07 0.48 garcinia livingstonei 0.27 0.01 0.13 0.01 ormocarpum bibracteatum… 0.04 0.47 0.09 0.47 14 table 6. cont’d. gardena triacantha 11.71 0.01 11.63 0 p. aquatica 0 0.02 10.36 0.02 gardenia aqualla 1.79 0 1.73 0 p. biglobosa 13.44 0.04 11.27 0.04 gardenia ternifolia 4.57 0 2.53 0 paullinia pinnata 0.13 0 0.11 0 gmelina arborea 3.5 0.03 2.5 0.02 persea americana 0 0 0.02 0 grewia barteri 0.23 0 0.33 0 phyllanthus muellerianus 50.51 0.06 48.9 0.07 grewia bicolor 4.3 0.11 1.43 0.09 phyllanthrus sp 0.03 0.08 0.03 0.08 grewia flavescens 0.2 0.11 1.2 0.11 phyllantus reticulatus 0.8 0.01 1.8 0.01 grewia venusta 0.03 0.02 0.02 0.02 p. thonningii 1024.91 0.02 948.63 0.01 grewia villosus 2.53 0.04 0 0.02 platycerium stemaria 0 0.09 0.19 0.06 gynocarpus americanus 0 0.02 0 0.01 psidium guajava 5.8 0 6.17 0.05 h. madagascariensis 1542.2 0.04 1511.9 0.01 psorospermum febrifigum 84.75 0 79.87 0.1 h. pulcherima 0 0 1.1 0.01 psorospermum senegalensis 66.88 0.12 63.23 0.11 hexalobus monopetalus 2.48 0 2.03 0.01 saba senegalensis 0.17 0.02 0 0.02 h. acida 3077.37 0 2907.2 0 sapium ellipticum 0.14 27.64 0 27.57 hyphaena tebaica 15.19 0.02 13.7 0 securida longepedunculata 38.49 0 36.1 0 jasmimum dichotomum 0.56 0.01 0.63 0 senna alata 77.1 0.45 74.77 0.46 keetia cornelia 0.02 0 0.17 0 senna javanica 0.03 0 0.01 0 keetia multiflora 0.95 2.14 0.07 0.02 senna sp. 0.07 9.21 0.01 9 keetia venusta 2.5 0.01 1.5 0.01 senna spectabilis 0.17 0 0.14 0 kigelia africana 0.43 0 0.17 0 sizygium guiénne var macrocarpum 257.07 0 257.07 0 landolphia heudelotii 1.27 0 0.3 0 sizygium guiennensis var guiennensis 14.24 0 23.5 0 lannea acida 4.1 0 1.53 0 steganotaenia araliacea 71.22 0.74 68.83 0.75 lannea chimperi 68 0 70.93 0 sterculia tragacantha 82.32 0 79.31 0.01 lonchocarpus laxiflorus 0.17 0 0.07 0 strichnos inocula 0.77 2.31 1.04 2.44 l. lanceolata 126.98 0 124.83 0 s. spinosa 18.68 0.76 17.7 0.76 mangefera indica 3.98 0 3.87 0 t. indica 0 0.6 0 0.6 maranthes polyandra 0 0 0.14 0 tectona grandis 0.4 0.12 0.4 0.1 margaritaria discoidea 0.03 0 0 0 tectonia grandulosa 1.68 0 0.23 0 maysa lanceolata 52.59 0.23 50.97 0.25 terminalia brownii 0 0 0.21 0 maytenus senegalensis 51.98 0.01 49.97 0 terminalia dewevrei 0.17 0.05 0.77 0.06 maytenus undatus 0.03 0 2.14 0 t.a glauscescens 614.19 0.35 605.87 0.34 morelia senegalensis 0 0.15 0.02 0.09 terminalia laxiflora 163.58 0.69 160.97 0.71 musa balbisiana 0 0 0 0 terminalia macroptera 112.1 0.05 133.4 0 mytragina sp 1 0.04 1 0.01 terminalia micrantha 143.7 0 120.1 0 neoboutonia velutina 4.85 0.61 4.4 0.67 terminalia sp 3.28 0 0 0 neocaria macrophylla 31.73 0 24.21 0 trema orientalis 2.47 0.13 1.46 0.22 15 table 6. cont’d. n. congesta 0 0.15 0.14 0.06 trickilia rocka 40.08 0.64 37.83 0.65 ochna afzeli 6.17 1.14 7.17 1.18 uapaca acuminata 0.38 0.01 0.07 0.01 uapaca heudeloti 0.99 0 2.37 0.02 uapaca chevalieri 0.06 0.03 1.36 0 uapaca paludosa 2.37 0 2.1 0 vitex madiensis 16.77 1.47 6.25 1.53 uapaca sp 0.05 0 5.77 0 vitex simplicifolia 1.74 1.01 1.6 1.27 uapaca vanhouttei 0.07 0.01 0 0.01 vitex sp1 0.26 0 0 0 uvaria angolensis 2.11 0.15 2.12 0.1 voacanga africana 10.13 1.29 6.63 1.14 uvaria chamea 0 2.18 0.25 2.27 voacanga thoursis 21.5 0.03 20.11 0.03 vepris herophylla 6.63 0 0 0 x. americana 17.25 0.02 10.77 0.01 vernonia amygdalina 0.13 0 0.13 0 xylopia parviflora 0.52 0 0.5 0 vernonia sp 0.02 0.02 1.01 0 zantozilum giletii 3.5 0.02 3.2 0.02 total 11134.2 100 10544 100 table 7. comparison of the regeneration rates according to the treatments and the types of savannas. t0 t1 t2 t3 mean standard deviation shrubby savanna 599.967 292.4 231.833 700.2 456.1 229.038 raised savanna 307.567 368.9 306.867 288.567 317.98 35.071 wooded savanna 268.267 171 605.6 147.767 298.16 211.503 average 391.933 277.433 381.433 378.844 357.41 53.618 standard deviation 181.231 99.795 197.7259 287.0683 191.46 76.784 fragments of the stems or by the climatic and zooanthropic factors. the density per hectares of the marked rejections passed from 1319 stems.ha -1 year -1 in 2004 to 623 stems.ha -1 in 2006 in shrubby savannas, 1317 stems.ha -1 in 2004 to 911 stems ha 1 year -1 in 2006 in raised savannas. in wooded savannas, the density of the rejections passed from 385 stems.ha -1 in 2004 to 158 stems.ha -1 year -1 in 2006 (figure 11). annual mortality of the species h. acida presents a very high number of dead individuals (66 stems ha -1 year -1 ) in the three types of savannas, followed by p. thonningii (30 stems ha 1 year -1 ) and a. senegalensis (23 stems ha -1 year -1 ) (table 8). in general, shrubby savannas are more threatened with regards to the mortality of the stems (12 stems ha -1 year -1 on average) per year. indeed, during the first stages of the development, some species have a high rate of mortality at the level of the seedlings. according to puig et al. (1989), this rate is often higher when the seedlings are gathered particularly near the foot of the tree; in fact, the roots of the tree emit toxic substances to the plants. the seedlings being heliophilous in the first stages of development, this mortality can also be due to the weak luminosity under the tree. the action of predator, caterpillars or the phytophagous parasites is not negligible on the mortality of the seedlings. floristic diversity in the savannas disturbed by the wood cuts abundance and specific richness of the vegetation there are abundant and rich species in the savannas of the peri-urban zone of ngaoundéré (table 9). it comes out that species are abundant in 16 1400 1200 1000 800 600 400 200 0 2004 2005 2006 figure 11. evolution of rejects of 2004 to 2006. table 8. annual mortality of the species (stems.ha -1 year -1 ). shrubby raised wooded scientific names a b c means a. zygia 3 3 1 2.01.0 a. africanus 4 6 39 16.014.9 a. senegalensis 42 18 10 23.012.3 b. ferruginea 1 0 5 2.02.0 combretum collinum 1 3 1 2.00.9 cussonia bartherii 1 2 5 2.01.4 c. macrostachys 2 4 2 2.00.8 e. africana 2 2 2 2.00.2 d. oliveri 20 23 1 15.09.1 ekenebergia senegalensis 1 3 13 5.04.9 e. sigmoidea 3 2 7 4.02.1 h. acida 143 50 4 66.051.6 l. lanceolata 3 2 3 2.00.6 protea madiensis 5 36 1 14.014.8 p. thonningii 56 20 14 30.017.1 p. febrifigum 9 2 1 4.03.4 f. glumosa 2 4 1 2.01.0 securidaca longepedonculata 7 5 3 5.01.4 sizygium guiennense var. macrocarpum 28 8 1 12.010.3 t. laxiflora 13 3 2 6.04.8 t. glaucescens 1 1 1 1.00.2 t. macroptera 2 4 1 2.01.0 steganotegea araliacia 1 0 1 1.00.3 trikilia emmental 3 4 3 3.00.6 h. madagascariensis 0 0 2 1.00.7 voacanga sp. 0 1 2 1.00.8 sysygium guiennense var guienense 0 1 2 1.00.7 flacourtia indica 1 0 1 0.30.2 vitex doniana 1 2 2 1.00.4 v. madiensis 0 1 0 0.20.2 mean 1215 78 44 8.02.7 a: shrubby savanna; b: raised savanna; c: wooded savanna. 17 table 9. specific abundance and richness of species a: specific abundance a; specific richness r. t0 t1 t2 t3 total types of savannas a r a r a r a r a r shrubby 240 77 197 67 211 65 205 64 853 273 raised 220 66 208 59 221 67 230 67 879 259 woode 242 81 239 83 247 90 246 76 974 330 tot 702 224 644 209 679 222 681 207 2706 862 table 10. values of the indices of shannon (ish), the equitability of piélou (eq), simpon (d) and its reverse (d') of the species in savannas according to the treatments. treatments ish eq ish/eq d d’ shrubby savannas t0 2.51 0.36 6.97 3.87 0.26 t1 2.29 0.33 6.94 2.78 0.36 t2 2.15 0.31 6.94 3.14 0.32 t3 2.09 0.3 6.97 2.94 0.34 raised savannas t0 2.11 0.3 7.03 3.38 0.3 t1 1.92 0.28 6.86 3.08 0.32 t2 2.2 0.32 6.88 3.38 0.3 t3 2.33 0.34 6.85 3.81 0.26 wooded savannas t0 2.71 0.39 6.95 4.16 0.24 t1 3.02 0.44 6.86 3.9 0.26 t2 3.27 0.47 6.96 4.2 0.24 t3 2.56 0.37 6.92 4.23 0.24 wooded savannas with a total of 914. indeed, the distribution of the diaspores in the wooded savannas by the zoochores is favourable to the abundance of the species. in these savannas, due to the seasonal cultures in the forest galleries by some farmers, there is less disturbance compared to shrubby savannas. the difference between shrubby and raised savannas is the weakness of species. they are respectively 853 and 879 for shrubby and raised savannas. ficher test at the doorstep of 5% shows that there is no significant difference between these types of savannas.specific richness in shrubby savannas (273) is largely higher than those of raised savannas (259) and wooded one (330).the intense activities of wood cuts and grazing are generally the factors of the recruitment of new exotic species, and are at the origin of this great richness in the shrubby savannas. the protected sites (702) are much richer. but with regard to the specific richness, there is no considerable difference between the various types of wood cuts. however, the richness is weak for t3 (207) compared to t0 (224). indices of shannon, the equitability of piélou, simpon and its reverse the indices of shannon (ish), the equitability of piélou (eq), simpon (d) and its reverse (d'), and the ratio ish/eq (table 10) are very high in the three types of savannas for the whole types of treatments. heterogeneity of the vegetation histogram of frequency for the whole savannas (figure 12) shows that cut savannas present a higher index of frequency in species. the species are thus much dispersed due to the phenomenon of wood cuts, however the vegetation is heterogeneous. relative frequencies of the species as a function of villages and various type of wood cuts the frequency of the species was evaluated for the villages as a function of the treatments in the various vegetable formations. it was found that the savannas of dang (university area) present a relative frequency of 11.21% for treatment t3 in shrubby and raised savannas. the impact of students’ activities can explain this high percentage. the relative frequencies are about 11.15% for the treatments t1 and t2 in the wooded savannas of béka hooseré where the populations exploit the forest galleries for agriculture. the same observations were 18 n u m b e rs o f s p e c ie s 90 80 70 60 50 40 30 20 10 0 i ii iii iv v indices of frequency figure 12. histogram of frequency of the species of savannas. table 11. relative frequencies of savannas according to the villages and the treatments (in %) savannas dang béka borongo ngaouhoura mbang ville beskewal daran tizon wakwa sa t0 8.07 8.27 10.39 6.52 7.78 6.43 8.53 8.9 11.11 9.67 sa t1 8.07 5.4 7.89 4.78 7.39 14.06 6.48 7.72 6.54 6.04 sa.t2 7.62 8.27 4.3 8.7 6.23 10.04 10.58 7.42 7.19 8.16 sat3 11.21 9.71 6.81 8.26 5.06 6.02 6.48 8.31 8.5 6.04 sb t0 10.76 5.76 8.6 8.26 8.95 6.83 7.51 6.83 7.52 10.57 sb t1 8.07 6.83 7.53 9.13 7.39 5.62 8.53 6.23 8.17 9.97 sb.t2 8.07 7.91 8.24 10.43 7.78 6.83 5.46 10.39 7.84 8.16 sb.t3 11.21 6.83 8.96 9.57 9.73 9.24 7.51 10.09 7.19 6.95 sc.t0 8.07 8.27 10.04 7.83 8.17 7.23 8.53 9.2 11.44 10.27 sc. t1 7.18 11.15 8.24 10 9.73 12.45 10.24 7.42 7.52 7.55 sc.t2 8.52 11.15 7.17 8.7 9.73 8.03 9.21 8.9 7.19 8.76 sc. t3 3.14 10.43 11.83 7.83 12.06 7.23 10.92 8.61 9.8 7.86 total 100 100 100 100 100 100 100 100 100 100 sa: shrubby savannas; sb: raised savannas: sc: wooded savannas. made in borongo and mbang-mboum for t3 in the savannas’ forest galleries with respective frequencies of 11.83 and 12.06%. shrubby t1 and wooded t1 of these cities respectively present the most significant relative frequencies of the whole site of study with the percentages of 14.6 and 12.45% (table 11). the density of the population imposed a strong pressure on these savannas. frequencies of the species by families in the whole savannas, 34 families were identified. the most frequent families are combrétaceae (10.53%), euphorbiaceae (9.77%) and mimosaceae (7.62%) with highest relative frequencies. but for the whole of the flora, the leguminous plants (cesalpiniaceae, mimosaceae and fabaceae) are most significant in relative frequency (table 12). on the other hand, the sapindaceous are more raised in percentage (15 %) followed by euphorbiaceae with 7.86%. analysis of autoecologic characters biological types table 13 presents the biological types of the savannas. it arises that the microphanerophytes (mcph) are dominant with 62.80%, while mesophanerophytes (msph) represent 19.49%. the least represented are megaphaneorophytes (mg ph) with 2.75%. this little percentage is explained by the low density of the trees with heights greater or equal to 30 m. the great representativeness of the microphone and mesophanerogames explain that these biological types adapt easily to guinean sava 19 table 12. frequency of the families of the vegetation of ngaoundéré. n° families fa fr ne % 1 anacardiaceae 87.50 3.83 3 2.14 2 annonaceae 120.0 5.25 5 3.57 3 apiaceae 43.33 1.90 1 0.71 4 apindaceae 53.33 2.33 2 1.43 5 apocynaceae 45.00 1.97 6 4.29 6 araliaceae 76.67 3.35 1 0.71 7 arecaceae 9.17 0.40 1 0.71 8 asteraceae 5.00 0.22 1 0.71 9 burseraceae 4.17 0.18 1 0.71 10 célastracaea 38.33 1.68 1 0.71 11 cesalpiniaceae 165.00 7.22 7 5.00 12 combretaceae 240.83 10.53 7 5.00 13 euphorbiaceae 223.33 9.77 11 7.86 14 fabacaea 80.00 3.50 5 3.57 15 flacourtiaceae 28.33 1.24 4 2.86 16 hymenocardiaceae 84.17 3.68 1 0.71 17 hypericaceae 155.0 6.78 3 2.14 18 indéterminée 21.67 0.95 2 1.43 19 meliaceae 56.67 2.85 8 5.71 20 mimosaceae 174.17 7.62 1 0.71 21 moracaea 78.33 3.43 10 7.14 22 myrsinaceae 20.00 0.87 10 7.14 23 myrtacaea 90.00 3.94 1 0.71 24 myrtaceae 15.00 0.66 2 1.43 25 ochnaceae 83.33 3.64 1 0.71 26 olacacaea 20.00 0.87 5 3.57 27 polygalaceae 23.33 1.02 1 0.71 28 proteacea 35.00 1.53 1 0.71 29 rubiaceae 77.50 3.39 1 0.71 30 rutaceae 8.33 0.36 6 4.29 31 sapindaceae 6.67 0.29 21 15.00 32 tiliaceae 17.50 0.77 1 0.71 33 ulmacaea 15.83 0.69 5 3.57 34 verbenaceae 84.17 3.68 4 2.86 total 2286.67 100.0 140 100.00 f: absolute frequency; fr: relative frequency; n e: species/family numbers; percentages of species/family. of adamaoua. there is no significant difference (p<0.05) among the treatments and between the savanicole types of formation. physiognomical distribution trees dominate the savanicole formation of the periurban zone of ngaoundéré. they represent 66.07% of the woody flora while 33.93% is represented by the shrubs (table 14). this result shows that the vegetation of ngaoundéré is a high guinean savannas formation where the species are among species of the wet dense forest and those of the sahelian savannas. phytogeographical distribution of the species the pantropicale species represent 96.80% of the whole flora (table 15) while the afro american species (aa) are represented by 0.90% of the flora, indeed these species are not in their surface of phytogeographical distribution. the flora is always made up at the same time of groups with more or less vast distribution, and endemic groups. 20 table 13. distribution of the biological types. types of savannas treatments mc ph mg ph ms ph nn ph total shrubby savanna t0 5.46 0.25 1.70 1.30 8.71 shrubby savanna t1 4.66 0.14 1.23 1.27 7.30 shrubby savanna t2 4.77 0.18 1.55 1.37 7.88 shrubby savanna t3 4.77 0.14 1.12 1.48 7.52 raised savanna t0 5.13 0.29 1.45 1.27 8.13 raised savanna t1 4.70 0.25 1.41 1.41 7.77 raised savanna t2 5.06 0.25 1.63 1.23 8.17 raised savanna t3 5.46 0.33 1.52 1.27 8.57 wooded savanna t0 5.57 0.25 1.81 1.30 8.93 wooded savanna t1 5.68 0.18 1.99 0.94 8.79 wooded savanna t2 5.75 0.18 2.21 0.98 9.11 wooded savanna t3 5.78 0.29 1.88 1.16 9.11 total 62.80 2.75 19.49 14.97 100.00 table 14. physiognomical distribution of the flora of ngaoundéré. type of savannas type of the wood cuts trees shrubs total shrubby savanna t0 5.94 2.77 8.71 shrubby savanna t1 4.35 3.02 7.38 shrubby savanna t2 4.97 2.88 7.84 shrubby savanna t3 4.93 2.66 7.59 raised savanna t0 5.36 2.77 8.13 raised savanna t1 4.97 2.81 7.77 raised savanna t2 5.33 2.81 8.13 raised savanna t3 5.47 3.17 8.64 wooded savanna t0 6.12 2.77 8.89 wooded savanna t1 6.08 2.66 8.74 wooded savanna t2 6.33 2.73 9.07 wooded savanna t3 6.23 2.88 9.10 total 66.07 33.93 100.00 a strong proportion of species to broad distribution can be an indication of degradation. the soudano-zambezian species are null. the whole savanicole formations are dominated by annual grasses. impact of wood cut on the dissemination of the diasporas table 16 presents the types of the diaspores met in the peri-urban zone of ngaoundéré. it releases from this table that the zoochores (18.56%) present a significant rate of dissimilation for the t0 treatment in the shrubby savannas. in protected savannas, the animals are the first freight agents of the diaspores. the second agents of dissemination in the shrubby savannas are anemochores (11.92%). the barrochores and hydrochores are found in small percentage in the wooded savannas. in the forest galleries, the barrochores are significant. according to the size of these diaspores, the speed of dissemination is low. it can be quoted that strichnos spinosa are species with low speed dissemination. the agents of their dissemination are the wind, the streaming water and the domestic animals. discussion impact of the wood cuts on the structure of the vegetation the size and the diameters of the stems in the savannas of the peri-urban zone of ngaoundéré have a structure of the type ”l''. this structure is the result of a strong pressure of the wood cuts on the vegetation. indeed, the repeated wood cuts by the population of ngaoundéré do 21 table 15. phytogeographical distribution of the species. type of savannas treatments aa pan pra tot t0 0.07 8.38 0.25 8.71 shrubby savanna t1 0.04 7.16 0.18 7.38 t2 7.66 0.18 7.84 t3 0.04 7.34 0.22 7.59 t0 0.04 7.95 0.14 8.13 raised savanna t1 0.07 7.63 0.07 7.77 t2 0.04 7.95 0.14 8.13 t3 0.11 8.38 0.14 8.64 t0 0.07 8.56 0.25 8.89 wooded savanna t1 0.18 8.31 0.25 8.74 t2 0.18 8.60 0.29 9.07 t3 0.07 8.85 0.18 9.10 total 0.90 96.80 2.30 100.00 table 16. dissemination of the species in savanna. types of savanna shrubby savanna raised savanna wooded savanna treatments t0 t1 t2 t3 tot t0 t1 t2 t3 tot t0 t1 t2 t3 tot an 2.9 2.99 2.87 3.13 12 2.78 3.5 3.36 3.36 13 2.66 2.25 3.63 2.78 11.32 ba 0.02 0.02 0.19 0.02 0.21 hy 0.02 0.05 0.07 sa 0.8 0.65 0.49 0.46 2.4 0.9 0.7 0.72 0.97 3.26 1.37 1.53 0.95 1.34 5.19 sc 0.2 0.05 0.14 0.09 0.5 0.09 0.1 0.07 0.14 0.39 0.23 0.19 0.16 0.23 0.81 zo 4.4 4.65 4.84 4.65 19 4.54 4 4.19 3.87 16.6 3.89 4.35 3.56 3.94 15.74 tot 8.3 8.33 8.33 8.33 33 8.33 8.3 8.33 8.33 33.3 8.33 8.33 8.33 8.33 33.33 an : anémochores, ba : barochores, hy : barochores; sa: sarcochores, sc : sclérochores, zo : zoochores not make possible quick reconstitution of the vegetation. this situation was checked in shrubby savannas with very strong and repeated cuts on the same trees during three years. it can be noted that seedlings with heights less than two meters and trees with little diameters are threatened in the whole savannas because of the intensity of wood cuts compared to the adult subjects; this justifies the structure in l of the vegetation of ngaoundéré. these results corroborate those of chouaibou (2006). in general, such a structure presents a good regeneration of the arborescent layers of the vegetable communities (anonymous, 1987). this result approaches those of mbolo (2005) who worked in the reserve of the biosphere of dja, southern cameroon, but differ from those of amougou (1986), sonké (1998), and gudjé (2002). indeed, the wood cuts are not the only factors that give this structure to savannas of ngaoundéré, there are also some factors not controlled like bush fires and the grazing practices which should be integrated to really understand the structural dynamics of the savannas. if ntoupka (1999) integrated these parameters in his work in the area of the far-north region, it was to seek exactlywhich was the major factor of modification of the structure of the vegetation of sudanese savannas impact of the wood cuts on the floristic composition of the species in our study we had on average 140 species, 60 kinds and 34 families; 371 alive stems.ha -1 year -1 in 2004 and 351 stems.ha -1 in 2006. these results are similar to those of thorgnang (2001) who listed 117 species in 80 kinds and 37 botanical families in the forest of gawar. our results are greater than those of mahamat (1991) in the national park of kalamaloué (4500 ha), with 21 species in 11 botanical families and that of teitcheugang (2000) with 75 species in 46 kinds and 24 families in the forest reserve of zamay. the richness of the savannas of ngaoundéré would be due to the anthropic factors which would support the dissemination of the species from an area to another. noubissié (2005) and tchobsala (2003) showed that d. 22 oliveri is classified among the species that are more suckering in adamaoua. as a whole, the number of the alive stems (371 stems ha -1 year -1 in 2004 and 351 stems ha -1 year -1 in 2006) is more significant compared to the results of several authors who worked on floristic diversity. dynamics of the reconstitution of the vegetation under the effects of the wood cuts reiterative capacity of the trees in savannas without cuts and with wood cuts the results showed that the average density of the rejections is 3712.45 stems.ha -1 year -1 for the individuals with circumference less than 3 cm in natural savannas. it is 1423.41 stems.ha -1 year -1 for individuals with circumference greater than 3 cm. the number of natural rejection is more significant compared to that of teitcheugang (2000) in the forest reserve of zamay (1133 ind.ha -1 year -1 ) for the individuals with diameter lower than 3 cm, 489 stems ha -1 year -1 for the individuals with diameter greater than 3 cm. the density of regeneration is higher than that found in the savannas of houbaré where combutum glutinosum is the densiest species in terms of regeneration with 700.36 stems.ha -1 . this species is least used by the local population. in addition to this species e. africana (272.27 stems ha 1 year -1 ), combutum sp. (198.27 stems ha -1 year -1 ), h. acida (164.45 stems.ha -1 year -1 ) have densities of more significant regeneration. teitcheugang (2000) found 573.8 stems.ha -1 year -1. in the forest reserve of zamay. our results are less than those of guejé (2002) (5613 stems.ha -1 year -1 ) for the trees which heights of the seedlings are lower than 100 cm. indeed the work of the later one was not carried out under the same conditions. it was carried out in the reserve of dja in the southern cameroon where the climate is favourable to regeneration. the capacity of reiteration of the seedlings is very significant at the time where trees are cut. in the savannas of ngaoundéré, h. acida and d. oliveri are the two species which have a fast capacity of regeneration. the wood cuts would support the regeneration of the seedlings. these results corroborate those of tchobsala (1997, 2003) where d. oliveri for example regenerated quickly and in abundance after wood cut and especially after bush fire. the second strategy of regeneration would be the germination of seeds. if in this work the most cut trees (t3) result in very rich seedlings from germination, the freight agents played a very significant role in the dissemination of the diaspores. cut woods are quickly replaced and recolonized by new species. endada africana and iliostigma thonningii are species which have a fast regeneration rate in savannas of the peri-urban zone of ngaoundéré (tchobsala, 1997). in terms of regeneration, the density of the rejections is more significant in the cut pieces. it is this dynamics of regeneration that makes it possible in the savannas of the peri-urban zone of ngaoundéré. if the local popu-lations do not make successive cuts on the same pieces and leave savannas in fallow for two to three years, the vegetation of ngaoundéré would not suffer from the phenomenon of degradation. mortality of the rejections without wood cuts the death rate of the seedlings is very remarkable in wooded savannas. this is mainly due to the effects of moisture in the rainy season, the termites and the trampling of the animals for the watering in dry season. sist et al. (1989) showed that the presence or the absence of the seedlings and their densities does not depend solely on the viability of seed but also of the ecological conditions (light intensity, hydromorphy of the ground). the mortality of the seedlings is also very marked in shrubby savannas due to the fact that these areas are grazing areas for domestic animals and subjected to successive cuts. the trampling of the animals makes lose a great number of the seedlings. in the same way, the repeated cuts affect the potentialities of development of the seedlings. mortality of the rejections after wood cuts the competition between the seedlings resulting from the rejections after wood cut is very marked in the first year when these seedlings are gathered near the tree’s foot as in the case of h. acida and s. guinense var macrocarpum. the roots of the tree secrete toxic substances to the plants and the seedlings being heliophilous in the first stages of the development. the mortality can also follow the weak luminosity below the tree’s foot. the action of predator, the caterpillars or the phytophagous parasites is not negligible on the mortality of the seedlings. this confirms the works of puig et al. (1989) who showed that the death rate of the rejections is often higher when the seedlings are gathered in particular near the tree’s foot. tchakounté (2001) showed that bush fire is not a negligible factor on the mortality of the seedlings. the death rate also depends on the age and the stage of development of the seedlings. gudjé (2002) showed that in the reserve of biosphere of dja, the risk of mortality of the seedlings decreases quickly when one passes from the young plants resulting from germination to the young trees installed in under wood. indeed while comparing the results of the two types of regenerations (without cuts and with wood cuts), one realizes that the mortality of the seedlings is more 23 significant in the cut pieces than in the pieces without cuts. dynamics of reconstitution of savannas of ngaoundéré letouzey (1968) admitted that savannas perished without the presence of man. from our results under the influence of the repeated and anarchistic wood cuts in the peri-urban sector of ngaoundéré, it would be difficult that savannas find their state of forest if the local populations are not put in co-administration with the ministries of forests and the structures specialized in the environmental protection; this fear is justified by the population’s increase. an alternative solution would be to leave savannas in fallow in some few years so that they should quickly reconstitute. the statements of the floristic composition of some sites in the forest galleries and savannas from 2004 to 2006 confirmed the declarations of letouzey (1968): "some shrubby savannas with t. glaucescens, p. thonningii, bridelia ferruginea, can settle gasoline sowings forest". factors like wood cuts, precipitations and fires play an important role into the forest dynamics of savannas (séghièri, 1990). these factors are responsible for the phenomena of embushment which corresponds to the degradation of a savannas towards denser vegetable formations dominated by one or some woody species. the dominant species of embushment in the area are: t. glaucescens, h. acida, p. thonningii and a. senegalensis. these species are generally essential for rejections and germination. conclusion and recommendations the wood cuts negatively influence the structure and the floristic diversity of the vegetation in the peri-urban zone of ngaoundéré. the types of the wood cuts have structures in "l". such a structure generally presents a good arborescent regeneration after cuts. the density of the stems is more significant in shrubby savannas with heights between 0 and 200 cm. in the three types of vegetable formations, there is a reduction in the number of the stems when the heights of the trees increase. from 200 cm the number of the stems is almost null. the number of the stems decreased from 2004 to 2006. this justifies the regression of the wet savannas of ngaoundéré. the characteristic and indicating species in the shrubby savannas under the strong pressure of the wood cuts are represented by h. acida, p. thonningii and a. senegalensis. on the other hand, for those of the wooded savannas are d. oliveri and cesalpinia sp., the very high cuts are depressive for the stability of the savannas and the disappearance of the vegetable biodiversity. consequently, they are responsible of the accelerated degradation and the alarming installation of the desert in wet savannas of ngaoundéré. the intolerant species towards wood cuts are t. indica, s. longepedunculata, parkia biglobosa s. spinos etc., these species can disappear easily when the pressure of the wood cuts is significant. savannas of the peri-urban zone of ngaoundéré have 142 species, 60 kinds and 34 families. the most represented families are combrétaceae (10.53%), euphorbiaceae (9.77%) and mimosaceae (7.62%), they present the strongest relative frequencies.there are two dynamic methods for the regeneration of the species: regeneration by germination of the diaspores and regeneration by rejection or drageonment after cut. the species that suffer after cuts are: h. acida (170 stems ha -1 year -1 ), p. thonningii (76 stems ha -1 year -1 ), annona senegalensis (35 stems.ha -1 ) and h. madagascariensis (30 stems ha -1 year -1 ), d. oliveri, a. africanus and p. aquatica. the biological types are dominated by trees formation. they represent 66.07% of the woody flora. 33.93% is represented by the shrubs. from the phytogeographical point of view, the panatropicales species represent 96.80% and the zoochochores 18.56%, showing a significant rate of dissimilation for the treatment t0 in the shrubby savannas. the reconstitution of the savannas of ngaoundéré is possible if the population reduces the rate of the wood cuts. to preserve the structure of the vegetation, some measure in co-administration between the government and the population should be considered to safeguard the anthropized vegetation of adamaoua. a dialogue among the civil authorities, administration in charge of forest, the local population, the nongovernmental organizations and the researchers is on the way to be installed in the region of adamaoua. to protect this threatened biodiversity, the populations could also choose inspection committees and forests guards, annual practise rotative and selective wood cuts. they should severely sanction those who cut wood fraudulently. it is recommended to the population to be aware on the wood cuts which are a danger to the survival of the vegetation consequently to the installation of the desert within the wet savannas of adamaoua. coadministration will encourage the collective plantations and community forests and expresses a wish of creation of the structures of the participative follow-ups (gic, associations, etc) for the protection and the safeguard of stressed savannas. acknowledgements we are thankful to the project prasac/ardesac for collaboration in this paper. we are also grateful to doctorr onana joseph and professor tchotsoua michel for assistance. 24 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bean weevil (93%) and maize weevil (73.3%) while enuopiri had average mortality effect; bean weevil (46.7%) and maize weevil (50%) all with extract concentration of 10 g/100 ml (extract/solvent). the overall results showed that bean weevil was much more susceptible to all the extracts than maize weevil, having recorded the height mortality rate. key words: bean weevil, maize weevil, lantana camara, african nutmeg, enuopiri, mortality. introduction corn, zea mays l., is a cereal grass related to wheat, rice, oat and barley; ranking second after wheat in order of world grain. this plant is regarded as versatile and has many uses since it can thrive in diverse climates; hence, it is grown in many countries. aside from being one of the major sources of food for both human and animals, it is also processed into various food and industrial products including starches, sweeteners, oil, beverages, industrial alcohol and fuel ethanol. moreover, thousands of foods and other everyday items such as toothpaste, cosmetics, adhesives, shoe polish, ceramics, explosives, construction materials, metal molds, paints, paper goods and textiles contain -corn components. in addition, corn products are rapidly replacing petroleum in many industrial applications. polylactide (pla), a biodegradable polymer made from corn is being used successfully in the *corresponding author. e-mail: oluwasinagbenga@yahoo.com. manufacture of a wide variety of everyday items such as clothing, packaging, carpeting, recreational equipment and food utensils of renewable resource (garcia, 1990). cowpea (vigna unguiculata (l.) walp.) is one of the most widely adapted, versatile, and nutritious grain legumes (ehlers and halla, 1997). it had been consumed by humans since the earliest practice of agriculture in developing countries of africa, asia and latin america, where it is especially valuable as a source of dietary proteins as well as vitamins and minerals (singh et al., 2003). though substantial quantities of cowpeas are produced, before harvest or during storage the seeds are vulnerable to infestation by many insect pests, constituting the major constraint on the food availability. over 90% of the insect damage to cowpea seeds is caused by the “cowpea weevil” callosobruchus maculatus f. (coeloptera: bruchidae), a pest to several pulses including chickpeas (cicer arietinum l.), lentils (lens culinars medik.), soybeans (glycine max mer.) and common beans (phaseolusvulgaris l.). indeed c. maculatus infestation on stored legumes may reach 50% within 3 to 4 months of storage (pascual-villalobos and ballestaacosta, 2003). maize weevil (sitophilus zeamais motschulsky), may infest the corn grain during storage and transport, attack may start in the mature crop when the moisture content (mc) of the grain had fallen to 18 to 20%. subsequent infestations in store result from the transfer of infested grain into store or from the pest flying into storage facilities, probably attracted by the odor of the stored grain. in stored maize, heavy infestation of this pest may cause weight losses of as much as 30 to 40%, although losses are commonly 4 to 5% (casey, 1994). the chewing damage caused by the weevil (bean and maize), brings about increased respiration in the seeds (hot spots), which promotes evolution of heat and moisture and in turn provides favorable living condition for molds leading to production of aflatoxin. subsequently, at very high moisture levels, bacterial growth is favored which ultimately gives rise to depreciation and finally total loss (dahiya, 1999). controlling stored pests is not an easy job although synthetic chemicals are available for use. effective pest control is no longer a matter of heavy application of pesticides (because many rural area farmers resulted to the use of large quantity insecticides because of lack of application knowledge), partly because of rising cost of petroleum – derived products but largely because excessive use of pesticide promotes faster evolution of resistant form of pests, destroys natural enemies, turns formerly innocuous species into pests, harms other nontarget species and contaminates food (busungu and mushobozy, 1991). there is, thus, an urgent need for control agents, which are less toxic to man and more readily degradable. among which is the use of botanical pesticides with low mammalian toxicity and can effectively prevent and/or suppress insect pests especially in storage (golob and webley, 1980) . it had been well reported that extracts from a variety of plants have potent insect pest-control properties, and they have being found to affect the biology of target insects in different modes such as ovicides, repellents, antifeedants, fumigants and contact toxicants, and insecticides (watanabe et al., 1993; hough-goldstein, 1990; karr and coats, 1988; rice and coats, 1994; tsao et al., 1995) . recently, herbal extracts that are not harmful to the environment, have been shown to be effective natural preservatives (grafius and hayden, 1998; sen, 2001). in addition, plantbased pesticides are renewable in nature and cheaper. also, some plants have more than one chemical as an active principle responsible for their biological properties. these may be either for one particular biological effect or they may have diverse ecological effects. the chances of developing quick resistance to different chemicals are highly unlikely (saxena et al., 1989). plant-derived pesticides can be transferred into practical applications in natural crop protection, which can help the small-scale farmers (binggeli, 1999). three locally available plants, lantana camara (verbenaceae), african nutmeg [monodora myristica (gaerth) dunal] and enuopiri [euphorbia lateriflora, schum and thonner] were evaluated to determine their nature as grain protectants against sitophilus zeamais and c. maculatus (f.). materials and methods this study focused on the effectiveness of hexane extracts of enuopiri stems, l. camara leaves and the seeds of african nutmeg as protectants of stored maize and bean grains against attack by s. zeamais and c. maculatus (f.). effectivity was based on the adult mortality tests under laboratory conditions. the experiment was conducted at the laboratory of chemistry department federal university of technology, akure, ondo state, nigeria, from august 2006 to november 2006. collection and preparation of test materials fresh and matured leaves of l. camara (from police headquarter akure) were gathered and brought immediately to the laboratory and stems of enuopiri (euphorbia lateriflora shum and thonner) were obtained from anu-olu hospital, ilobu, osun, state), while african nutmeg seeds [monodora myristica (gaerth) dunal] were bought at akure main market (oja oba). mr. solomon o. aduloju of department of crop soil and pest management, futa, authenticates these materials. the leaves and the stem materials were air dried in the laboratory until crispy and african nutmeg seeds were dehulled. the materials were pulverized using a laboratory blender and sieve to obtain uniform particle size. the resulting powders were kept separately in glass containers with screw capa and stored at room temperature prior to use. 300 g of each of the materials were then exhaustively extracted with nhexane using a soxhlet apparatus. these extracts were concentrated and kept separately in different labelled bottle containers and stored in a refrigerator. mass rearing of weevil adult maize weevil (s. zeamais motschulsky) and bean weevil [c. maculatus (f.)] were isolated respectively from already infested maize grains (z. mays) and cowpea [v. unguicalata (l.) walpa] obtained from the research laboratory of the department of crop, soil and pest management, futa, ondo state, nigeria. materials such as corn seeds and cowpea used to culture the weevil were thoroughly cleaned and exposed in an oven to ensure the absence of insects, mites or disease-causing microorganisms. the treated corn seeds and cowpea seeds were then respectively put inside rubber containers previously washed, sterilized and dried. into the containers containing corn seeds were added isolated maize weevil and to the container containing cowpea seeds were added bean weevil, respectively, from maize and bean weevil obtained from infested maize and bean grains. the plastic containers were covered with a net fastened tightly with rubber bands. the rearing of the insects was done in the laboratory to adapt them to the laboratory condition. the rearing was given enough time until new adult insects emerged; these were then used for the experiment. adult mortality test five different test concentrations (w/v of extract /hexane) were prepared: 10, 7.5, 5, 2.5 and 1 all in g/100 ml respectively. 0.5 ml table 1. percentage yield of the extracts. plant solvent mass of extracts obtained (g) % yield of extracts african nutmeg hexane 58.35 19.45 lantana camara 39.45 13.15 enu opiri 43.52 14.51 prepared solution of varying concentration was applied inside different petri-dishes that had been previously washed, sterilized and dried, while 0.5 ml hexane (without the extract) was poured inside separate petri-dishes as control. all the petri-dishes were left overnight for the solvent used for preparing the solution to evaporate before introducing the weevil. after 24 h, 10 untreated (uninfested) cowpea and corn seeds were respectively placed in the centre of different petri-dishes, (including the control). ten active adult bean weevil (c. maculatus) and maize weevil (s. zeamais motschulsky) were placed in each of the petri-dishes containing the cowpea and maize seeds, respectively. to the control petri-dishes were also added ten active adult bean weevil (c. maculatus) and maize weevil (s. zeamais motschulsky), respectively. the petridishes were then loosely covered to allow passage of air. weevil mortality was assessed and recorded after 1, 6, 12, 18 and 24 h. the experiment was carried out in triplicate. percent adult mortality was determined by counting the number of dead insects divided by the total number of insects introduced multiplied by 100, (lajide and escoubas, 1990] statistical analysis the data obtained were analysed by probit analysis using duncan’s multiple range test (dmrt) and analysis of variance (anova), while regression analysis model was used for the computation of ld50 and ld90 results the result of the percentage extract yields was presented in table 1 below. african nutmeg hexane extract had the highest yield followed by enu-opiri and l. camara respectively. table 2 presented the result of the percentage insect mortality of the extracts on bean weevil. significant treatment effects were observed with the number of the dead insects after the treatment duration. table 3 shows the lethal dose analysis of the percentage insect mortality. the result collaborated the effectiveness and the economic valuability of african nutmeg above other extracts table 4 presents the result of percentage insect mortality of extracts on maize weevil. the result showed that among the botanical extracts used, african nutmeg had the highest insect mortality and enu-opiri had the lowest, after 24 h treatment. table 5 presents the lethal dose activity of the extract, indicating that african nutmeg was superior protectant among all the extract, with small quantity of its extract achieving highest insect mortality discussion the result of the percentage extract yields from the various plants as presented in table 1 showed that african nutmeg hexaneextract had the highest yield of 19.45%, while l. camara had 13.15% and enuopiri had 14.51% yield. thus african nutmeg had 4.91 and 6.30% yield higher than enu-opiri and l. camara extracts, respectively. enu-opiri had 1.36% extract yield higher than lantana camara, which had the lowest extract yield among all the extract: extract yield (%)  mass of extract obtained x100 % mass of sample the result of the percentage insect mortality of the extracts on bean weevil as presented in table 2 indicated that african nutmeg hexane extract had superior effectiveness among all the botanical extracts. having 76.70% insect mortality with 1 g/ 100 ml of extract treatment after 24 h, while l. camara had 20.00% and enu-opiri had 6.7%. the effectives of african nutmeg above other extracts were confirmed after treatment at various hour(s). african nutmeg extract was able to record 100% insect mortality with 10 g/100 ml of its extract at 1, 6, 12, 18 and 24 h of insect treatment, while l. camara had 93.3% and enu-opirih had 46.70% all with 10 g/ 100 ml, only after 24 h of treatment. the result from table 3 showed that it would be economical to embark on mass production of african nutmeg hexane extract for use as protectant of grains, because small quantity of .65 g/ 100 ml (ld50) was able to achieve 50% insect mortality and 2.4 g/100 ml (ld90) was able to kill 90% of the insect within 24 h of the treatment, as against the use of 5.30 g/ 100 ml (ld50) and 9.51 g/100 ml (ld 90) for l. camara extract, while enu-opiri (ld50) and (ld90) was undetectable within the test period and with the extract mass used.the result of percentage insect mortality of the extracts against maize weevil presented in table 4 showed that insect mortality increased with increase in the mass of the extract used and treatment duration, though none of the extract was able to achieve 100% mortality after 24 h treatment. african nutmeg still had the highest mortality of 96.70% after 24 h treatment with 10 g/ 100 ml extract, l. camara had 73.3% and enu-opiri had 50.00%. table 5 presented lethal dose result of the plant extracts. table 2. percentage mortality of hexane extracts on bean weevil. plant extract conc exposure duration (h) (g/ 100 ml) 1 6 12 18 24 1 20.0±0.0 b 33.3±3.3 b 50.0±5.8 b 66.7±3.3 b 76.7±3.3 b 2.5 36.7±3.3 c 46.7±6.7 c 60.0±5.8 b 73.3±3.3 c 90.0±5.8 c a. nutmeg hexane 5 53.3±3.3 d 70.0±5.8 d 86.7±6.7 c 93.3±3.3 d 100.0±0.0 d 7.5 73.3±3.3 e 86.7±6.7 e 93.3±3.3 c,d 100.0±0.0 d 100.0±0.0 d 10 100.0±0.0 f 100.0±0.0 f 100.0±0.0 d 100.0±0.0 d 100.0±0.0 d 1 3.3±3.3 a 6.7±3.3 a,b 13.3±3.3 b 16.7±3.3 b 20.0±0.0 b 2.5 10.0±0.0 b 13.3±3.3 b,c 20.0±0.0 b 26.7±3.3 c 26.7±3.3 b l. camara hexane 5 16.7±3.3 b 23.3±3.3 c,d 33.3±3.3 c 40.0±0.0 d 46.7±3.3 c 7.5 16.7±3.3 b 30.0±5.8 d 43.3±3.3 d 53.3±3.3 e 60.0±5.8 d 10 30.0±0.0 c 43.3±3.3 e 56.7±3.3 e 66.7±3.3 f 93.3±3.3 e 1 0.0±0.0 a 0.0±0.0 a 0.0±0.0 a 3.3±3.3 a,b 6.7±3.3 a,b 2.5 0.0±0.0 a 3.3±3.3 a 6.7±3.3 a,b 10.0±0.0 b 10.0±0.0 b e. opiri hexane 5 6.7±3.3 a,b 13.3±3.3 b 16.7±3.3 b,c 20.0±0.0 c 26.7±3.3 c 7.5 10.0±5.8 b 16.7±3.3 b 23.3±3.3 c,d 33.3±3.3 d 40.0±0.0 d 10 13.3±3.3 b 26.7±3.3 c 33.3±3.3 d 40.0±0.0 d 46.7±3.3 e control 0 0.0±0.0 a 0.0±0.0 a 0.0±0.0 a 0.0±0.0 a 0.0±0.0 a values are means of three replicate ± standard error. column means followed by different letters are significantly different at p < 0.05. a.nutmeg represents african nutmeg, e.opiri represents enu opiri. table 3. the ld50 (g/ 100 ml) and ld90 (g/ 100 ml) of extracts on bean weevil. duration (h) african nutmeg l. camara enuopiri hexane ld50 extract ld90 hexane ld50 extract ld90 hexane ld50 extract ld90 12 0.74 6.74 9.08    18 0.71 4.39 6.01    24 0.65 2.49 5.30 9.51   represents cases where ld can not be calculated from result. african nutmeg is the best extract for mass production, since it was able to achieve 50 and 90% insect mortality with the least extract mass of 1.48 g/100 ml (ld50) and 8.97 g/100 ml among all the extracts, against 6.96 g/ 100 ml (ld50) for l. camara and 9.62 g/100 ml (ld50) for enuopiri. the ld90 of l. camara and enu-opiri was undetectable in conclusion, results of the study revealed that all tested plant extracts exhibited mortality action against maize weevil and bean weevil, with bean weevil been the most susceptible to the plant extracts. african nutmeg hexane extract had 100% bean weevil insect mortality with 5 g/ 100 ml after 24 h of treatment, whereas 73.3% mortality was recorded for maize weevil. with 10 g/ 100 ml extract mass applied after 24 h african nutmeg, l. camara and enu-opiri respectively were able to record 100, 9.30 and 46.7% for bean weevil, but had 96.7, 73.3 and 50% respectively for maize weevil. the efficacies of different treatments varied, depending on the source of the active ingredient. lantadene a, lantadene b and high flavonoid content, which is mostly associated with deterrence against insects are present in l. camara (ghisalberti, 2000), african nutmeg contained among other charicol, thymol, a – pinene and myristicin a poisonous constituent (dales, 1996; cobley, 1976) and enuopiri contained high quantity of secondary metabolites (segler, 1994). this result finds support from other studies in which plant extracts were effective in controlling bean weevil and maize weevil, and that they have been effectively used as stored product protectant against insect pests (bunner, 1993; ofuya et al., 1992; aku et al., 1998; singh et al., 1978; pandey et al., 1981 table 4. percentage mortality hexane extracts on maize weevils. plant extract conc exposure duration (h) (g/ 100 ml) 1 6 12 18 24 1 16.7±3.3 a,b 26.7±3.3 b 3 3.3±3.3 b 46.7±3.3 b 46.7±3.3 b 2.5 26.7±3.3 b 36.7±3.3 b,c 43.3±3.3 b,c 53.3±3.3 b,c 56.7±3.3 b a. nutmeg hexane 5 43.3±8.8 c 43.3±3.3 c 53.3±3.3 c 63.3±3.3 c,d 73.3±6.7 c 7.5 53.3±8.8 c 56.7±3.3 d 6 6.7±3.3 d 73.3±6.7 d 76.7±8.8 c 10 60.0±5.8 c 70.0±0.0 e 83.3±8.8 e 90.0±5.8 e 9 6.7±3.3 d 1 3.3±3.3 a 6.7±3.3 a,b 10.0±0.0 b 10.0±0.0 b 10.0±0.0 b 2.5 3.3±3.3 a 13.3±3.3 b,c 16.7±3.3 b 20.0±0.0 c 20.0±0.0 c l. camara hexane 5 1 3.3±3.3 b 20.0±0.0 c,d 30.0±0.0 c 36.7±3.3 d 40.0±0.0 d 7.5 16.7±3.3 b 26.7±3.3 d 33.3±3.3 c 43.3±3.3 d 53.3±3.3 e 10 2 6.7±3.3 c 40.0±5.8 e 53.3±3.3 d 63.3±3.3 e 73.3±3.3 f 1 0.0±0.0 a 3.3±3.3 a 6.7±3.3 a 10.0±0.0 b 10.0±0.0 b 2.5 3.3±3.3 a 10.0±0.0 a 16.7±3.3 b 16.7±3.3 c 20.0±0.0 c e.opiri hexane 5 16.7±3.3 b 23.3±3.3 b 23.3±3.3 b 23.3±3.3 d 30.0±0.0 d 7.5 16.7±3.3 b 26.7±3.3 b 33.3±3.3 c 33.3±3.3 e 36.7±3.3 e 10 20.0±5.8 b 30.0±5.8 b 36.7±3.3 c 40.0±0.0 f 50.0±0.0 f control 0 0.0±0.0 a 0.0±0.0 a 0.0±0.0 a 0.0±0.0 a 0.0±0.0 a values are means of three replicate  standard error. column means followed by different letters are significantly different at p < 0.05. a.nutmeg represents african nutmeg, e.opiri represents enu-opiri. table 5. the ld50 (g/100 ml) and ld90 (g/ 100 ml) of extracts on maize weevil. duration (h) african nutmeg l. camara enu opiri hexane ld50 extract ld90 hexane ld50 extract ld 90 hexane ld50 extract ld90 12 4.09  9.75    18 1.78 9.60 8.02    24 1.48 8.97 6.96  9.62   represents cases where ld can not be calculated from results. therefore, the results findings revealed that african nutmeg, l. camara and enuopiri hexane extracts could be used as protectant against maize weevil, s. zeamais motsch and bean weevil, c. maculatus (f.). it is recommended therefore that a similar study be conducted by using separately the other parts of the test plants like roots, flowers or even the whole plant to further evaluate their efficacy against maize weevil, bean weevil and other important stored product pests. in addition, the use of other solvent to extract those plants is also recommended to further determine their potential as insecticide against storage seed pests refferences aku aa, ogunwolu eo, attah ja (1998). annona senegalensis l. (annonaceae) performance as botanical insecticide for controlling cowpea seed bruchid, callosobruchus maculatus (f.) (coleoptera: bruchidae)in nigeria. j. plant dis. protection, 105: 513-519. bunner jp (1993). pesticidal compounds from higher plants. pesticide sci., 39: 95-102. binggeli p (1999). lantana camara l. (verbenaceae). retrieved october 12, 2005 from http//www. memberslycos .co.uk/woodyplant ecology/docs/web_spd.htm. busungu dc, mushobozy dmk (1991): the efficacyof various protectants against zabrotes subfasciatus (boh) (coleoptera: bruchidae) in common beans. bean res., 6: 62–76. casey sd (1994). neem: mode of action of compounds present in extracts and formulations of azadirachta indica seeds and their efficacy to pests of ornamental plants and to non-target species. retrieved october 12, 2005 from:http://www. colostate.edu /depts/entomology/ courses/en570/ papers_1994/sclar.html. cobley ls (1976). an introduction to botany of tropical crops. longman group ltd. london, p. 371. dahiya s (1999). alternatives to chemical pesticides.retrieved october 12, 2005 from http:// www.tribuneindia.com/1999/99 jul26/agrohtm # dales mj (1996). a review of plant materials used for controlling insect pests of stored products. nri bulleting 65, chatham, uk. nat. resour. inst., p. 84. garcia jr (1990). bioassay of five botanical materials against the bean weevil, callosobruchus chinensis (l.) on mungbean (vigna radiata l.), unpublished master’s thesis. university of the philippines at los baños, college, laguna. ghisalberti el (2000). lantana camara (verbenaceae). fitoterapia, 71: 462-487. golob p, webley dj (1980). the use of plants and minerals as traditional protectants of stored products. tropical products institute g138. now post harvest pest and quality section, natural resources institute, chatham, united kingdom. grafius e, hayden j (1988). insecticide and growth regulator effects on the leafminer liriomyza trifolii (diptera: agromyzidae), in celery and observations on parasitism. great lakes entomol., 21: 49-54. ofuya ti, okoye bc, olola as (1992). efficacy of crude extract from seeds of monodora myristica (gaertn) as surface protectant against callosobrus maculatus, attacking legume seeds in storage. j. plant dis. protection, pp. 528-532. pandey gp, doharey rb, varma bk (1981). efficacy of some vegetable oils for protecting greengrain against the attack of callosobruchus maculatus. indian j. agric. sci., 51: 910-912. saxena rc, jilani g, kareem aa (1989). effects of neem on stored grain insects in jacobson (ed.) forum on phytochemical pesticides. volume i. the neem tree. boca raton, florida: crc press. segler ds (1994). phytochemistry and systematic of the euphorbiaceae. annals of the misssouri bot gard., 81: 380 – 401. sen s (2001). determination of effetcs of some plant phenols on wood protection. phd thesis, universitiy of karaelmas, institute of science, zonguldak turkey, p. 295 singh sr, luse ra, leuschner k, nangju d (1978). groundnut oil treatments for the control of callosobruchus maculatus during cowpea storage. j. stored prod. res., 14: 77-80. in ternationa l scholars journa ls african journal of environmental economics and management issn 2375-0707 vol. 9 (5), pp. 001-009, may, 2021. available online at www.internationalscholarsjournals.org © international scholars journals author(s) retain the copyright of this article. full length research paper the role of the miombo woodlands of the southern highlands of tanzania as carbon sinks p. k. t. munishi*, s. mringi, d. d. shirima and s. k. linda department of forest biology, faculty of forestry and nature conservation, sokoine university of agriculture, p. o. box 3010, morogoro, tanzania. accepted 18 october, 2020 inventory and monitoring of existing carbon pools in ecosystems is important for establishment of baselines for reduced emissions from deforestation and forest degradation (redd) as well as understanding the global carbon budget. we used tree dimensions to quantify the carbon pools of two sites in miombo woodlands of the southern highlands of tanzania. mean above ground carbon density of the miombo ecosystem was 19.2t ha -1 . of the total carbon, 40 and 60% was contributed by stems and branches respectively. different species contributed differently to carbon stocks in these ecosystems with brachystegia spiciformis and julbernardia globiflora contributing the most. the estimated carbon stocks in this ecosystem is within the range observed in dry forests elsewhere though they are in their early stages of regeneration after extensive exploitation pressure. under proper management there is a tremendous capacity for carbon storage in these miombo woodlands to mitigate carbon emissions. since miombo species tend to invest much in roots an assessment of below ground carbon in roots can add to the carbon storage potential of these ecosystems. evaluation of the root and soil carbon in these ecosystems is important in determining the full potential of these ecosystems to act as carbon sink. key words: miombo woodlands, biomass, carbon, reduced emissions from deforestation and forest degradation, emission mitigation, climate change. introduction the rise in atmospheric carbon dioxide (co2) concentration will have varying implications on global climate (wayburn, 2000; munishi et al., 2000; munishi and shear, 2004). land use changes and forest management activities have historically been and are currently net sources of carbon (c) as co2 gas to the atmosphere (brown et al., 1996). however, depending on land use system, different ecosystems can be important sources or sinks for carbon (levy et al., 2004). there is a historical controversy as whether terrestrial ecosystems are releasing carbon to the atmosphere or withdrawing it and accumulating it in vegetation biomass and soils (broecker et al., 1979; houghton et al., 1987; kauppi et al., 1992; wisniewski et al., 1993). it is *corresponding author. e-mail: pmunishi2001@yahoo.com. however, widely known that terrestrial ecosystems in general play a major role in the global carbon budget and fluxes (brown, 1997, 1999; dixon, 1996; munishi, 2001; munishi and shear, 2004). previous analyses have suggested that land vegetation contain as much carbon as present in the atmosphere. furthermore, as much as 10% of the atmospheric carbon dioxide could be taken up and released annually by vegetation. others suggest that terrestrial vegetation must be a source of carbon because deforestation proceeds faster than forest re-growth (houghton et al., 1987). land use changes and forest management activities have high potential to mitigate carbon emission. forest management offers one of important options for mitigation c emissions. available options in forest management include avoiding emissions, conserving the existing c pools on the land (slowing down deforestation or improving forest harvesting), reduced deforestation and forest degradation, expanding c storage in forest ecosystems by increasing the area and/or carbon density of forests (e.g. by plantations, agro-forestry, natural regeneration, soil management) (brown, 1999; dixon et al., 1994; dixon, 1996; walker et al., 2008), increasing storage in durable wood products and substituting sustainably grown wood for energy intensive and cement based products (e.g. bio-fuels, construction materials) (koluchigina et al., 1995; winjum et al., 1998). terrestrial ecosystems especially forest vegetation have the greatest potential for mitigating atmospheric co2 emissions through conservation and management (brown et al., 1996; munishi et al., 2000; munishi and shear, 2004) . changes in forest cover, use, and management, produce sources and sinks of co 2 that is exchanged with the atmosphere (heygreen and bowler, 1989; jackson, 1992; chidumayo, 1993). assessment and monitoring of the existing carbon pools in forest ecosystems is important for understanding the global carbon budget especially when such ecosystems are relatively extensive and cover large areas. forest ecosystems in tanzania occupy more than 35% of the land area (mnrt, 1998) and more than one third of this is occupied by the miombo woodlands (mnrt, 1998; monela et al., 2005). the miombo ecosystem is one of the tropical wildernesses in the world covering about 3.6 million km 2 and spanning ten countries in east and central africa. in africa miombo woodlands cover an area of 2.7 mill. km 2 extending from angola, kongo, zambia, malawi, mozambique, tanzania and zimbabwe. in tanzania it covers about two thirds of the country (fyhrquist, 2005). the vegetation of this area is primarily woodland, dominated by trees in the legume sub-family ceasalpinoideae with the genera brachystegia, julbernardia and isoberlinia dominating and a welldeveloped underlying layer of grass. the dominance of one family of trees provides the unifying feature for this ecosystem (frost, 1996; chidumayo, 1990; wwf, 2003). the miombo ecosystem contains a diverse of major woodland types including wet miombo, dry miombo, burkea-terminalia woodlands, baikiaea woodland, mopane woodland, acacia-combretum woodland, dry evergreen forests (cryptosepalum). the miombo woodlands are however, undergoing the greatest change in tanzania due to heavy use for supply of fuel wood and other sources of energy (mapaure and campbell, 2002). although, the miombo woodlands ecosystems of tanzania are likely to have high potential for carbon storage and mitigating co2 emissions, reliable estimates for their potential are few and inadequate. an analysis of the potential of the miombo woodland ecosystems to sequester or store carbon is a key to understanding whether the correctives measures taken in land use changes and forest management within the miombo woodland biome are likely to create net carbon sources or sinks. such assessments are also fundamental in quantifying pathways for ecosystem carbon fluxes and sequestration in the miombo woodlands. in this study estimate of the biomass and carbon pools of a miombo woodland ecosystem in southern tanzania was made using relatively easily measured tree dimensions like diameter at breast height (dbh). such estimates are important in designing management plans for the miombo woodlands that will ensure a sustained potential of this ecosystem’s contribution to emission mitigation. specifically carbon prediction models for miombo woodlands of southern tanzania were developed using tree dbh as the predictor variable and the models were then use to make estimates of the biomass and carbon storage of the ecosystem. materials and methods study site mbozi district in mbeya region is located in the south western corner of mbeya region, between latitudes 8 and 9° 12" south of the equator and longitudes 32° 7' 30" and 33° 2' 0" east of greenwich meridian. to the south district is bordered by ileje district, to the east by mbeya rural district at the mark of songwe river, to the north, mbozi district extends to lake rukwa where it is bordered by chunya district, whereas to the west it shares borders with rukwa region and the republic of zambia. mbozi district is composed of 6 divisions namely igamba (1,754 ha), iyula (900 ha), kamsamba (2,708 ha), msangano (821 ha), ndalambo (2,454 ha) and vwawa (750 ha) (figure 1). two sites were selected based on the extent of miombo vegetation in the region. longisonte forest reserve is located in vwawa division and zelezeta village forest reserve in igamba division. both forests are a local authority forest reserves with an area of 1,041 and 220 ha respectively. these forests are mainly composed of miombo woodlands dominated by genera brachystegi, julbernadia and isoberhinia species (mzoma et al., 1995). the forests have other associate species to these genera such as uapaca kirkiana and parinari excelsa. the climate of the area is bimodal with a rain season in october to may and a dry season in june to september. most of the area is dominated by clay soils with high swelling and shrinkage characteristics data collection a total of 30 temporary circular sample plots of radius 15 m (0.02 ha) were established systematically in each of the two sites. all trees with dbh 6 cm were measured for dbh. each tree was identified in both the scientific and local name. for trees that were not identifiable in the field voucher specimens were collected for confirmation with an assistance of a taxonomist. trees whose scientific names could not be ascertained were reported by their vernacular names. based on species composition and dominance a total of 15 sample trees in each site were selected and measured for dbh. the trees were then felled, separated into stems and branches and then crosscut into billets that could be weighed. the billets were then tied into bundles and weighed in the field to obtain field tree weights of branches and stems. finally two discs of about 2 cm thickness were crosscut from the stem and branch for laboratory analysis of basic density and biomass ratio. data analysis the stem and branch discs from the field were cut into small samples of 2 x 2 cm, then soaked in water for one week and study site figure 1. map showing the study site within tanzania (adopted and modified from fyhrquist et al., 2002). weighed for green weight. the samples were then oven dried at 103 ± 2°c to a constant dry weight. the biomass ratio was computed as the ratio of the oven dry weight to green weight for each tree stem and branch samples. the biomass ratio was used to convert the field tree weight (stem and branches) into biomass for the sample trees. we determined tree biomass through regression models using the diameter dbh as predictor variable for each component (chamshama et al., 2004; malimbwi et al., 1994; munishi et al., 2000, munishi and shear, 2004). carbon prediction models were developed for each component using the diameter dbh as predictor variable (haygreen and bowler, 1989; jackson, 1992; malimbwi et al., 1994; munishi et al., 2000) . although, other variables may influence carbon storage in trees, dbh is the most significant and easily measured predictor variable for biomass accumulation in forestry systems (haygreen and bowler, 1989; jackson, 1992; malimbwi et al., 1994; munishi et al., 2000, munishi and shear, 2004). these equations were used to predict carbon storage (t/ha) by above ground vegetation from the plot tree diameter data. the amount of carbon was computed by multiplying the biomass by 50% and converted into per ha basis table 1. carbon prediction models for stems and branches in miombo woodlands in mbozi district, southern highlands of tanzania. location dependent variable model r 2 p vwawa (longisonte) stem carbon 0.0069dbh 2.9756 0.66 0.0001*** branch carbon 0.0489dbh 2.1623 0.46 0.0001*** igamba (zelezeta) stem carbon 0.0172dbh 2.5702 0.71 0.0001*** branch carbon 0.5606dbh 2.4067 0.34 0.0001*** *** = significant at 0.99 confidence limit. table 2. carbon storage potential in miombo woodlands at longisonte and zelezeta forest reserves in mbozi district, southern highlands of tanzania. location carbon density (t ha -1 ) stem % branch % total vwawa (longisonte) 9.5 53 8.5 47 17.9 igamba (zelezeta) 5.7 28 14.6 72 20. 4 average 7.6 40 11.5 60 19.2 (haygreen and bowler, 1989; munishi and shear, 2004) . the estimates for stem and branches were done independently using respective models for each stem and branches to avoid cumulative errors that could result from an estimate of one parameter from another parameter. results allometric models for carbon prediction table 1 shows the allometric models developed to estimate the amount of carbon stored by the miombo woodlands ecosystem in the two sites. though the models are all significant the branch biomass prediction models seem not to be strong enough to correctly predict the biomass of the tree branches. however, given the variations that exist in trees within these ecosystems the models can be used as the first approximation of tree stem and branch biomass in these ecosystems. carbon content of the miombo ecosystem we estimated above ground tree carbon to be 20.4 t ha -1 for the zelezeta and 17.9t ha -1 for longisonte forest reserves. this makes an average carbon density of 19.2 t ha -1 in the ecosystem. in longisonte forest reserve 53% of the carbon density comes from stems and 47% from branches where as in zelezeta site 28% come from stem and 72% from branches. overall stem carbon makes about 40% of the total carbon in the ecosystem while branches contribute the larger proportion of about 60% (table 2 and figure 2). proportional contribution to c stocks by different species we observed differences in carbon stocks as contributed by different species. julbernardia globiflora store the highest amount of carbon per unit area in longisonte forest reserve followed by brachystegia spiciformis, uapaca kirkiana, brachystegia bohemii and parinari excelsa accounting for 66.5% of the total carbon. the other 13 species accounted for the remaining portion (33.5%) . in the zelezeta site b. bohemii contributed the highest in carbon storage followed by b. spiciformis, p. excelsa, albizia antunesiana and u. kirkiana. these species accounted for 98.1% of the total carbon while the remaining 5 species accounted for the remaining proportion. the four species accounting for the most carbon are common in miombo woodlands in the south though the most common miombo species are b. spiciformis, b. bohemii and j. globiflora. uapaca and parinari sometimes form unique associations in these ecosystems with uapaca forming pure stands on well drained areas thus their high contribution to carbon storage in this miombo ecosystems (tables 3 4 and figures 3 6). discussion we estimate carbon density in this study to an averaged of 19.12 t ha -1 and which is relatively higher than earlier estimates of 6.45 t ha -1 c for a coastal miombo at kitulanghalo forest reserve (malimbwi et al., 1994) and a highland miombo in tabora (backeus et al., 2006). these c ( % ) 70 60 50 40 30 20 10 0 m h c te n s ra b figure 2. percent contribution of ecosystem c by different tree parts in the miombo woodlands, southern tanzania. table 3. aboveground carbon as contributed by different species in miombo woodlands at longisonte reserve, southern highlands of tanzania. species carbon density (t/ha) % stem branch total j. globiflora 2.52 1.67 4.21 23.6 b. spiciformis 1.42 1.11 2.47 13.8 u. kirkiana 1.01 1.11 2.12 11.9 b. bohemii 0.82 0.78 1.60 9.0 parinari excelsa 0.72 0.75 1.48 8.3 hymenocardia acida 0.51 0.58 1.12 6.3 lannea schimperi 0.60 0.41 1.04 5.8 combretum zeyherii 0.59 0.41 0.96 5.3 crossopteryx februfugia 0.40 0.34 0.73 4.1 pseudolachynostylis maprouneifolia 0.21 0.28 0.50 2.8 combretum molle 0.19 0.26 0.46 2.6 commiphora fischeri 0.18 0.21 0.39 2.2 dalbergia nitidula 0.07 0.11 0.18 1.0 diplorhynchus condylocarpon 0.09 0.10 0.18 1.0 afromosia angolensis 0.05 0.08 0.13 0.7 syzigium guineense 0.04 0.07 0.11 0.6 commiphora mossambicensis 0.04 0.07 0.10 0.6 lonchocarpus bussei 0.05 0.03 0.08 0.5 total 9.49 8.36 17.86 100 differences in carbon densities might be due to varying degree of exposure to human degradation, difference in age of the tree species and the type of miombo woodlands involved. williams et al. (2007) clearances due to agriculture are estimated reduce carbon stocks by 19.0 t c ha -1 in miombo woodland of mozambique. various studies show that different ecosystems have different biomass and carbon densities. for example the c density estimates from afromontane rain forests of the eastern arc mountains were found to be between 252 and 581 t c ha -1 (munishi, 2001; munishi and shear, 2004; eccm, 2007; munishi and shirima, 2010a, b). the table 4. above ground carbon as contributed by different species in miombo woodlands at zelezeta, mbozi district, southern highlands of tanzania. species name carbon density (t/ha) % stem branch total b. bohemii 2.46 9.48 11.94 58.5 b. spiciformis 1.71 3.01 4.72 23.1 p. excelsa 0.74 1.04 1.78 8.8 a. antunesiana 0.41 0.52 0.93 4.6 u. kirkiana 0.28 0.37 0.65 3.2 c. molle 0.05 0.06 0.11 0.5 cussonia arborea 0.04 0.06 0.10 0.5 ochna ovata 0.04 0.06 0.09 0.5 bridelia micrantha 0.03 0.04 0.07 0.4 total 5.75 14.6.3 20.39 100.0 c ( % ) 25.0 20.0 15.0 10.0 5.0 0.0 j . g lo b if lo ra b . s p ic if o rm is u . k ir k ia n a b . b o h e m ii p . e x c e ls a species figure 3. percent contribution to ecosystem carbon by the most dominant species in miombo woodlands at longisonte reserve in mbozi district, southern highlands of tanzania. eastern miombo woodlands in tanzania have been shown to have c storage potential of between 25 and 80 t ha -1 (eccm, 2007; shirima, 2009). brown et al. (1993) observed that only about 6% of mature forests in tropical asia had more than 122.5 t ha -1 c while a 60-year rotation plantation of tectona grandis (teak) in tanzania had 244 t ha -1 c, (o’kting’ati et al., 1998 quoted in munishi, 2001; munishi and shear, 2004). it is very possible that the amount of c stored by these ecosystems will be higher if other carbon pools like the undergrowth of herbaceous layer, litter and other organic debris and tree samplings with dbh below 6 cm which are relatively numerous in some parts of the forests were included. further soil c adds much to the potential for c storage in these ecosystems. disturbance in the study site due to human utilization may also have contributed to lowering the c stock in these forests. forests that have been subjected to human disturbances tend to have lower biomass and hence c storage than their potential (brown, 1997). human destruction of tropical forests is estimated to contribute up to 17% of global carbon dioxide emissions, resulting in accelerated global warming. one mechanism proposed to mitigate these emissions is reduced emissions from deforestation and forest degradation (redd) in developing countries, otherwise known as reduced emissions from deforestation and degradation (redd+; that is the original concept of redd, plus 30 25 20 stem c (t/ha) c ( t/ h a ) 15 10 5 0 branch c (t/ha) j . g lo b if lo ra b . s p ic if o rm is u . k ir k ia n a b . b o h e m ii p . e x c e ls a species figure 4. total contributions to ecosystem carbon by the stem and branches of the most dominant species in miombo woodlands at longisonte and zelezeta forest reserves in mbozi district, southern highlands of tanzania. c ( % ) 70 60 50 40 30 20 10 0 b . b o h e m ii b . s p ic if o rm i s p . e x c e ls a a . a n tu n e s ia n a u . k ir k ia n a species figure 5. percent contribution to ecosystem carbon by the most dominant species in miombo woodlands at longisonte and zelezeta forest reserves in mbozi district, southern highlands of tanzania. sustainable management of forests and conservation and enhancement of forest carbon stocks). this proposed mechanism forms part of an international move to include emissions from habitat change (especially the loss of carbon-rich ecosystems such as forests) in a more comprehensive agreement under the un framework convention on climate change (unfccc), which it is hoped will become operational in 2012. if an international redd+ mechanism is to be successful, with minimal displacement of greenhouse gas emissions between countries (known as international leakage), it is important that developing countries hosting a large proportion of the 100 90 80 stem c (t/ha) 70 branch c (t/ha) 60 )( t/ h a 50 40 c 30 20 10 0 b . b o h e m ii b . s p ic if o rm is p . c u ra le ll if o li a a . a n tu n e s ia n a u . k ir k ia n a species figure 6. total contributions to ecosystem carbon by the stem and branches of the most dominant species in miombo woodlands at longisonte and zelezeta forest reserves in mbozi district, southern highlands of tanzania. world’s forest are ready to participate shortly after its launch. a key aspect of determining the carbon benefit of any forest carbon project is to accurately quantify the levels of carbon changes to known levels of precision. determination of carbon changes requires baselines that is historical trends against which additional carbon benefits as a result of carbon project can be determined. under redd, the reference scenario will be the baseline against which achievements made by a country can be measured and credited. possible options for crediting forest carbon management include reduction in emissions from deforestation; reduction in emissions from degradation; enhancement; forest conservation; and conservation of the existing carbon stock. the last two options relate to forests with long protection status which would be credited based on the maintenance of carbon stock which would be compensated through a “conservation” fund that would be included under redd. since the redd policy is likely to be undertaken nationally, the country deforestation baseline need to be determined by depicting historical land use changes and typical carbon stock data for different types of forests to calculate the changes in c stocks over time. assessments of carbon stocks in different land use systems especially forests and woodlands are therefore among the important national redd readiness activities that portrays the baseline information on c stocks as tanzania prepares for the anticipated redd mechanism. conclusions and recommendations given their extent there is apparently a tremendous capacity for the miombo ecosystem of southern tanzania to store carbon and act as c sink if properly managed. efforts to ensure proper management of the miombo ecosystem putting emphasis on the dominant species e.g. b. spiciformis, b. boehmii and p. excelsa can contribute to the creation of a considerable carbon sink and will ensure persistent potential for the miombo woodlands to store c as sinks rather than emission sources thus contribution to the redd process in tanzania and global initiatives at large. on the other hand the miombo ecosystem is widely utilized by the adjacent communities for various purposes, creating high degradation pressure on the ecosystem. in this respect managing the carbon stocks of these ecosystems require a concerted effort to reduce the human related degradation. this can partly be achieved by allowing the adjacent communities to harvest wood products from the forest under proper management to recover some of their socio-economic values and ensure local community participation in the management and conservation of the miombo ecosystem. such carbon can as well be a source of revenue from carbon trading and under proper benefit sharing mechanism can contribute to poverty reduction among the adjacent local communities. further managing the carbon stocks in this extensive carbon rich ecosystem will contribute to global initiatives in combating global warming. if this is realized it will as well contribute to sustainable forest and woodland management in tanzania. references backeus i, petterson b, stromquist l, ruffo c (2006). tree communities and structural dynamics in miombo (brachystegia – julbernardia) woodland, tanzania. j. for. ecol. manage., 230: 171-178. brown s (1997). estimating biomass and biomass change in tropical forests. a primer fao forestry paper no. 134. brown s (1999). guidelines for inventorying and monitoring carbon offsets in forest – based projects. a report prepared for the world bank, washington, dc, usa, p. 13. broecker ws, takahashi t, simpson hj, pens th (1979). fate of fossil fuel carbon dioxide and the global carbon budget. science, 206: 409 – 418. brown s, hall cas, knabe w, raich j, trexler mc, women p (1993). tropical forests: their past, present and potential future role in the terrestrial carbon budget. j. water, air soil pollut., 70: 71 – 94. brown s, sathaye m, cannell m, kauppi p (1996). mitigation of carbon emission to the atmosphere by forest management. commonwealth for. rev. 75: 80 – 91. chamshama sao, mugasha ag, zahabu e (2004). stand biomass and volume estimation for miombo woodlands at kitulangalo, morogoro, tanzania. s. afr. for. j., 200: 59-64. chidumayo en (1990). above-ground woody biomass structure and productivity in a zambezian woodland. for. ecol. manage., 36: 33-46. chidumayo ne (1993). inventory of wood used in charcoal production in zambia.biodiversity support program publications database no. 25. washington, dc, usa., p. 10. dixon rk, winjum jk, andrasko kjj, schroeder pe (1994). integrated systems: assessment of promising agroforestry and alternative landuse practices to enhance carbon conservation and sequestration. climate change, 30: 1 – 23. dixon rk (1996). agroforestry systems and greenhouse gases. agrofor. today, 8(1): 11 – 14. edinburgh centre for carbon management (eccm) (2007). 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(verbenaceae), an exotic from tropical america, has invaded vast areas of forests surrounding nayar river in garhwal himalayas (uttarakhand, india). several factors like high reproductive potential, absence of preferred predators, evergreen nature and sufficient moisture provided by river water favour extraordinary growth of l. camara in this area. in this study, the impact of l. camara invasion on basal area cover, density, frequency and abundance of various plant species was determined. invasion was able to change the quality (composition, distribution) and quantity (growth in number and size) of different species in this region. the invasion was also found to have some relation with native-exotic nature and different plant habits (like tree and herbs) of local flora. as determined by various ecological indices, there was significant loss of species richness and diversity in invaded localities. in total, there was a 28.4% decrease in species richness of invaded localities. excluding l. camara, nearly 63% loss of basal area of vegetation was recorded in the invaded localities compared to not invaded ones. there was also an impression that l. camara favoured exotics over endemic species in this riparian zone. key words: invasion, lantana camara, riparian, species richness, species diversity, garhwal himalaya. introduction there is a plethora of biological invasions across the blue planet in the 21 st century. they affect ecological processes, which sooner or later contribute to the loss of biodiversity from native ecosystems (vitousek, 1988; baret et al., 2004; lodge et al., 2006; pauchard and shea, 2006). after habitat destruction, this is the second most extensive threat to global biodiversity on continents, and second to none in the case of islands (sharma et al., 2005a). risk is not only restricted to biodiversity loss, as invasive alien species (ias) also threaten the environment, *corresponding author. e-mail: dobhalp1@yahoo.co.in, kumar.prv1@rediffmail.com. abbreviations: ias, invasive alien species. economies, and human welfare (lodge et al., 2006). therefore global efforts are being made tocontrol these invaders. in india, a large number of exotics are naturalized, affecting the distribution of native flora. a few among them have conspicuously altered the vegetation patterns of the country. reddy (2008), reported 173 ias from india, 80% introduced from the neotropics. the most prominent invasive species include ageratum conyzoides l., chromolaena odorata l., eupatorium adenophorum spreng, lantana camara l., mikania micrantha kunth, mimosa invisa (mart.) solms, parthenium hysterophorus l. and prosopis juliflora (sw.) dc. among terrestrial plants, and eichhornia crassipes (mart.) solms and pistia stratiotes l., among aquatic ias. all these species are principal threats to the native flora (sharma et al., 2005b; hajra and negi, 2007). p. hysterophorus and a. conyzoides 2 are mainly invaders of agroecosystems and pastures throughout india (kohli et al., 2006; javaid et al., 2009); c. odorata , e. adenophorum, m. micrantha are mainly invaders of forest, pastures and wastelands of himalayan region, north-east and south-east india (ramakrishnan, 1991; kunwar, 2003; muniappan et al., 2005). specifically in the north-western himalayas, invasive plants such as l. camara, p. hysterophorus and a. conyzoides are the most problematic weeds (kohli et al., 2004; dogra et al., 2009a, b). amongst these l. camara is considered as one of world’s top 100 invasive species and top 10 worst weeds of the world (sharma et al., 2005a; iucn, 2009). it is a major invader of forests, pasture and wastelands throughout the india (dobhal, 2010). the success of l. camara may be attributed to large number of fruits per plant (kohli et al., 2006; dobhal, 2010), its ability to grow under a wide range of climatic conditions (day et al., 2003), allelochemicals released by roots in the soil inhibiting the growth of neighbouring plants (ambika et al., 2003; yadav et al., 2004), and possession of some feeding deterrents that probably render them less acceptable to generalist herbivores than non-invasive plants (jogesh et al., 2008; sharma et al., 2007). its dominance in invaded areas and possession of poisonous components like triterpenes leads to forage scarcity and bad health or deaths of animal (morton, 1994; ghisalberti, 2000; sharma et al., 2007). this species also possess ability to change socio-economic scenario of invaded regions. in india, its invasion is associated with estimated loss of us$ 924 million per year (pimentel et al., 2000). this ias also dominates traditional rain fed agriculture areas of mountainous himalaya and the interest of the farmers towards agriculture is declining rapidly (maikuri et al., 2001). these left out terraced agricultural fields, orchards and nurseries appears even more intensely dominated by this weed. although it is well known that l. camara is a serious invader of various terrestrial ecosystems, there are few studies which emphasize the magnitude of the influence of this weed on the biodiversity of native ecosystems (sharma et al., 2005a). for example, sharma and raghubanshi (2007) reported this invasive as being responsible for differential depletion of native trees. in himalayas, this was found to be associated with marked decreased species density, frequency, abundance and basal area and biomass of other species of invaded community (bhatt et al., 1994; dobhal et al., 2009). the explicit impact of l. camara invasion in riparian zones is also not reported, particularly in india. to fill this gap, a study was conducted in the paurigarhwal region of uttarakhand, the himalayan state in northern india. here, large areas surrounding the river nayar are invaded by this weed. it was hypothesized that invasion of l. camara led to degradation of typical structure of valuable flora in this riparian ecosystem in terms of richness, diversity and native /exotic composition of species. study area the study was conducted in the pauri garhwal (29°45´30°15´n latitude and 78°24´ -79°23´e longitude), a district of uttarakhand state, situated in northern india. at an altitude of 600 m asl, running amid two ranges of lesser himalaya (dudhatoli pauri range in the north-east and lansdowne mussoorie range in the south-west), nayar is a major tributary of the river ganges (figure 1). the characteristic riparian vegetation of this region is dominated by acacia catechu willd. and dalbergia sissoo roxb. trees with associated shrubs and herbs such as carissa opaca stapf ex haines, barleria cristata l., cissampelos pareira l., ichnocarpus frutescens (l.) r. br., justicia adhatoda l., launaea acaulis (roxb.) babcock ex kerr., murraya koenigii (l.) spreng., sida cordata (burm. f.) borss. waalk., ziziphus mauritiana lam. there is heavy invasion of l. camara on both sides of the nayar river. methods data collection the study area was divided into 3 sites; each covered a stretch of approximately 2.5 3 km along the river (figure 1). at each site 4 quadrats, each measuring 4 × 4 m 2 were laid randomly in l. camara invaded localities. a corresponding “control quadrat” was laid in nearby non-invaded localities at 50 m away from each of these quadrats. in order not to miss any species, these studies were continued in four seasons namely spring (february to april), summer (may to july), monsoon (august to october) and winter (november-january). in this manner 96 quadrats were sampled during a year. in each quadrat, plants of each species were counted; basal area of each plant was calculated using a screw gauge for thin vegetation and vernier caliper or meter tape for thick stems. however, when there was high density of individuals of a particular herb species (e.g. grasses) and it was extremely difficult to separate each of them, the mean density of individual in 12 subquadrats was calculated. all these sub-quadrats were 100 cm 2 each and arranged in a random systemic design (barbour et al., 1999) inside the larger quadrat measuring 1600 cm 2 . this mean density when multiplied with total area of larger quadrat gave total number of individuals present inside. in other case when there were 100 individuals of a species in a quadrat, a mean basal area for randomly chosen 100 individual of that species from that specific quadrat was calculated and used as a representative basal area for that species in that particular quadrat. data analysis the collected plants were identified to species level with the help of available floras duthi (1911), gaur (1999) and online annotated checklist of flora of nepal available online at www.efloras.org. for comparison with type specimens, the herbarium of botany department, panjab university and botanical survey of india (b.s.i.), dehradun were also consulted. species were characterized on the basis of their exotic-native status with the help of “flora of the district garhwal north-west himalaya” (gaur, 1999) and “germplasm resources information network” (grin, 2008) an online database. species were also categorised on the basis of their growth forms viz. climber, herb, shrub, tree and under-shrub. quantitative analysis of plants for per cent basal area, 3 figure 1. location map of study area showing different sites of study. abundance, density, frequency and importance value index (ivi) was done as per misra (1968) and ambasht (1990) . qualitative analysis in terms of richness, diversity and evenness indices was done using different methods. species richness was calculated according to margalef (1958), menhinick (1964) and peet (1974) as given in sagar and singh (1999). diversity was calculated in terms of fisher's diversity index (fisher et al., 1943), shannon's index h' (shannon and weaver, 1963), simpson's index (simpson, 1949), hill's number n1 and n2 (hill, 1973), using biodiversity pro version 2.0 (mcaleece, 1997). distribution of diversity was calculated in terms of evenness number e1 (pielou, 1969) and e2 (sheldon, 1969) calculated per the method given in sagar and singh (1999), using the applicable ecological software package from ludwig and raynold (1988). significance of difference between data was determined by tukey-test using spss software. results a total of 89 plant species were recorded from the study area, of which 81 were found in noninvaded localities, 58 in l. camara invaded localities and 50 were common to both localities (table 1). there were 31 species (table 1) found exclusively in non-invaded localities or absent from invaded localities. standing out against these 31 sensitive species there were just 8 species, namely chloris dolichostachya, jatropha curcas, neyraudia arundinacea, phyllanthus virgatus, ricinus communis, saccharum spontaneum, sida acuta and woodfordia fruticosa which occurred exclusively in invaded areas, and may therefore be considered more resistant to l. camara invasion compared to all other species found in the study area. in comparison to non-invaded sites there was 28.4% reduction in species richness in invaded sites. among species which were common to invaded and non-invaded localities cyanotis vaga, phyllanthus urinaria, boerhavia diffusa and vallaris solanacea were most severely influenced by invasion. their ivi values in invaded localities were reduced respectively, to 25.1, 34.5, 43.0 and 15.7% of non-invaded localities. the other species demonstrating strong negative impacts of l. camara invasion were: oxalis corniculata and murraya koenigii throughout the year; cissampelos pareira and launaea acaulis during spring; gnaphalium hypoleucum, geranium nepalens, vallaris solanacea and aerva sanguinolenta during summer; and cyanotis cristata, physalis minima, dioscorea belophylla, parthenium hysterophorus and aerva sanguinolenta during monsoon. the greatest number of species shows negative impacts during the winter, including mallotus philippensis, aerva sanguinolenta, securinega virosa, ageratum conyzoides, barleria cristata, parthenium hysterophorus, ipomoea 4 table 1. inventory of plants in the study area in decreasing order of their ivi in lantana camara invaded localities followed by species found exclusively in non-invaded localities. s/no. botanical name (family) and habit annual mean of importance value index native and exotic invaded localities non-invaded localities status* / native range 1. lantana camara l. (verbenaceae) / s 89.43 ± 9.29 4.10 ± 1.08 e / tropical america 2. murraya koenigii (l.) spreng. (rutaceae) / s 39.12 ± 12.18 65.08 ± 10.74 n / india, asia 3. ziziphus mauritiana lam. (rhamnaceae) / s 18.94 ± 4.26 17.08 ± 2.97 n / india 4. dalbargia sissoo roxb. (fabaceae) / t 14.54 ± 2.77 14.99 ± 6.14 n / india, pakistan, afghanistan, myanmar 5. acacia catechu willd. (mimosaceae) / t 14.05 ± 0.08 15.92 ± 3.69 n / india, malaysia 6. carissa opaca stapf ex haines (apocynaceae) / s 10.57 ± 1.73 10.47 ± 2.53 n / india, pakistan, sri-lanka, myanmar 7. euphorbia hirta l. (euphorbiaceae) /h 8. cassia occidentalis l. (caesalpiniaceae) / u-s 9. parthenium hysterophorus l. (asteraceae) / h 10. eragrostis tenella (l.) p. beauv. ex roemer & schultes (poaceae) / h 11. ipomoea hederifolia l. (convolvulaceae) / c 12. saccharum spontaneum l. (poaceae) / h 13. oxalis corniculata l. (oxalidaceae) / h 14. corchorus aestuans l. (tilliaceae) / h 8.64 ± 0.14 4.11 ± 2.09 n / pantropics 7.56 ± 3.92 3.03 ± 1.59 e / tropical america 6.98 ± 2.43 10.15 ± 5.77 e / tropical america 6.23 ± 1.66 1.36 ± 0.46 n / india, tropical and temperate asia, africa 6.16 ± 4.75 4.48 ± 3.82 e / america 6.11 ± 4.87 ---n / india, pantropics 5.03 ± 1.17 16.98 ± 8.03 o / cosmopolitan 4.39 ± 5.07 2.35 ± 4.70 o / neotropics (probably) 15. ageratum conyzoides l. (asteraceae) / h 16. aerva sanguinolenta (l.) blume (amaranthaceae) /h 17. cissampelos pareira l. (manispermaceae) / c 18. pyrus pashia buch. ham. ex d. don (rosaceae) / t 19. ichnocarpus frutescens (l.) r. br. (apocynaceae) / c 20. celtis australis l. (ulmaceae) / t 21. launaea acaulis (roxb.) babcock ex kerr (asteraceae) / h 22. phyllanthus virgatus g. forst. (euphorbiaceae) / h 23. martynia annua l. (martyniaceae) / h 24. sida cordata (burm. f.) borss. waalk. (malvaceae) / h 25. cassia tora l. (caesalpiniaceae) / u-s 26. neyraudia arundinacea (l.) henrard (poaceae) / h 27. trichosanthes cordata roxb. (cucurbitaceae) / c 28. solanum incanum l. (solanaceae) / s 29. capparis zeylanica l. (capparaceae) / s 30. boerhavia diffusa l. (nyctaginaceae) / h 31. securinega virosa (roxb. ex willd.) baillon (euphorbiaceae) / s 32. woodfordia fruticosa (l.) kurz (lythraceae) / s 33. triumfetta rhomboides jacq. (tiliaceae) / u-s 4.38± 1.24 8.15± 6.87 3.99 ± 2.09 6.82 ± 2.19 3.82 ± 1.17 5.54 ± 1.29 3.38 ± 0.50 1.02 ± 0.32 3.26 ± 0.61 1.71 ± 1.70 3.16 ± 0.43 2.98 ± 0.84 2.57 ± 1.34 2.13 ± 0.46 2.47 ± 1.70 --- 2.46 ± 2.84 1.91 ± 2.59 2.45 ± 0.84 2.56 ± 1.53 2.28 ± 2.63 1.17 ± 1.19 2.19 ± 2.12 --- 1.80 ± 2.08 0.78 ± 1.56 1.72 ± 1.17 2.21 ± 0.18 1.69 ± 0.46 1.41 ± 0.34 1.38 ± 0.84 3.21 ± 5.95 1.24 ± 0.25 1.60 ± 0.49 1.21 ± 0.23 --- 1.12 ± 1.29 0.46 ± 0.93 e / tropical america n / india, bhutan, china, myanmar, malaysia, nepal e / america n / india, bhutan, myanmar n / india, sri-lanka, thailand, indonesia e / africa, south europe, turkey n / india, afghanistan, pakistan n / india, sri-lanka, china e / north america, mexico e / america e / south america n / india, tropical-asia, africa n / india, myanmar n / india, africa n / india, tropical and temperate asia o / widely naturalized n / india, asia, africa n / india, burma, china, africa n / india, china, malaysia, africa 5 table 1 contd. 34. phyllanthus urinaria l. (euphorbiaceae) / h 1.09 ± 0.85 3.16 ± 5.98 35. vallaris solanacea (roth) kuntze (apocynaceae) / c 1.04 ± 0.71 6.64 ± 1.58 36. chloris dolichostachya lagasca (poaceae) / h 1.01 ± 0.70 --- 37. gnaphalium hypoleucum dc. (asteraceae) / h 1.00 ± 1.15 3.70 ± 6.48 38. cyanotis cristata (l.) d. don (commelinaceae) / h 0.93 ± 1.07 1.50 ± 2.66 39. ipomea cairica (l.) sweet (convolvulaceae) / c 0.91 ± 0.64 0.21 ± 0.43 40. jatropha curcas l. (euphorbiaceae) / s 0.91 ± 0.64 --- 41. physalis minima l. (solanaceae) / h 0.86 ± 0.99 2.04 ± 2.39 42. pupalia lappacea (l.) juss. (amaranthaceae) / h 0.83 ± 1.66 0.55 ± 1.10 n / indian subcontinent, indochina, china, japan n / india, tropical and temperate asia n / india, afghanistan, china, myanmar, srilanka n / indian himalayas japan, china, bhutan n / india, tropical asia, tropical africa e / australia, america, new-zealand e / tropical america e / tropical america, africa n / india, pakistan, s.e. asia, africa, madagascar 43. cryptolepis buchananii roem. & schult. (asclepiadaceae) / c 44. mallotus philippensis (lam.) muell. arg. (euphorbiaceae) / t 45. ampelocissus latifolia (roxb.) planchon (vitaceae) / c 46. holoptelea integrifolia (roxb.) planch. (ulmaceae) / t 0.72 ± 1.43 1.52 ± 0.55 n / india, china, malaysia 0.71 ± 1.42 6.06 ± 1.67 e / australia 0.67 ± 0.77 0.46± 0.91 n / india, indian subcontinent 0.66 ± 1.32 3.79 ± 0.59 n / india, nepal, myanmar, sri-lanka, indo-china 47. asparagus filicinus buch.-ham. ex d. don (asparagaceae) / s 48. geranium nepalense sweet (geraniaceae) / h 49. cyanotis vaga (lour.) j. a. & j. h. schult. (commelinaceae) / h 50. cypreus niveus retz. (cyperaceae) / h 51. gomphrena globosa l. (amaranthaceae) / h 52. dioscorea belophylla (prain) j.o. voigt. ex haines (dioscoreaceae) / c 53. rhus parviflora roxb. (anacardiaceae) 54. peristrophe bicalyculata (retz.) nees (acanthaceae) / h 55. sida acuta burm. (malvaceae) / h 56. euphorbia helioscopia l. (euphorbiaceae) / h 57. barleria cristata l. (acanthaceae) / u-s 58. ricinus communis l. (euphorbiaceae) / s 59. abrus prectoris l. (fabaceae) / c 60. anisomeles indica (l.) kuntze (lamiaceae) / h 61. arthraxon prionodes (steudel) dandy (poaceae) / h 62. asclepias curassavica l. (asclepiadacea) / h 0.65 ± 0.48 1.05 ± 0.63 n / india, china, indo china, myanmar 0.61 ± 0.44 1.13 ± 1.34 n / india, tropical and temperate asia 0.46 ± 0.53 1.83 ± 3.65 n / india, pakistan, burma, africa 0.41 ± 0.48 0.15 ± 0.30 n / india, s. and s. e. asia, tropical africa 0.34 ± 0.39 0.11 ± 0.22 e / tropical america 0.33 ± 0.39 0.89 ± 0.36 n / indian himalayas 0.32 ± 0.64 0.16 ± 0.32 n / india, nepal, sri lanka 0.26 ± 0.52 0.29 ± 0.58 n / india, nepal 0.26 ± 0.52 ---e / africa 0.26 ± 0.52 0.16 ± 0.31 e / eurasia 0.24 ± 0.47 0.41 ± 0.81 n / india, myanmar, indo-china 0.22 ± 0.44 ---e / tropics, africa ---0.97 ± 0.71 n / india, old world tropics ---0.65 ± 1.30 n / india, china, malaysia ---3.00 ± 6.00 n / india, tropical and temperate asia, africa ---0.17 ± 0.34 e / tropical america 6 table 1. contd. 63. atylosia scarabaeoides (l.) benth. (fabaceae) / h 64. brachiaria reptans (l.) gardner & c. e. hubbard (poaceae) / h 65. butea monosperma (lam.) kuntze (fabaceae) / t ---0.10 ± 0.21 ---3.97 ± 4.65 ---12.62 ± 0.92 n / india, china, malaysia n / india, tropical and sub-tropical asia, africa n / india, nepal, pakistan, malaysia, indo-china 66. cannabis sativa l. (cannabaceae) / h ---0.37 ± 0.73 n / india, central asia 67. cassia fistula l. (caesalpiniaceae) / t ---6.84 ± 0.55 n / india, myanmar 68. circium verutum (d. don) sprengel (asteraceae) / h ---0.41 ± 0.83 n / india, pakistan, afghanistan coccinia grandis (l.) voigt (cucurbitaceae) / c --- n / india, tropical and 69. 0.54 ± 1.07 temperate asia , africa 70. dioscorea bulbifera l. (dioscoreaceae) / c ---0.12 ± 0.24 71. eupatorium adenophorum spreng. (asteraceae) / s ---0.54 ± 0.37 72. flacourtia indica (burm. f.) merrill (flacourtiaceae) / s ---0.12 ± 0.24 73. galium asparifolium wallich (rubiaceae) / h ---0.98 ± 1.96 74. galium elegans wall. ex roxb. (rubiaceae) / h ---2.27 ± 4.54 75. gloriosa superba l. (liliaceae) / h ---0.21 ± 0.42 76. grewia optiva j. r. drumm. ex burret (tiliaceae) / t ---0.56 ± 0.43 77. jasminum arborescens roxb. (oleaceae) / c ---1.19 ± 2.38 78. justicia adhatoda l. (acanthaceae) / s ---3.21 ± 0.58 79. lactuca dissecta d. don (asteraceae) / h ---1.38 ± 2.75 80. malvastrum coromandelianum (l.) garcke (malvaceae) / ---0.61 ± 0.71 h 81. momordica dioica roxb. ex willd. (cucurbitaceae) / c ---0.45 ± 0.89 82. naringi crenulata (roxb.) nicolson (rutaceae) / t ---2.07 ± 0.38 83. oenothera rosea l'herit. ex aiton (onagraceae) / h ---1.98 ± 3.95 84. rhamnus virgatus roxb. (rhamnaceae) / s ---0.20 ± 0.40 85. saussurea candicans (dc.) sch. bip. (asteraceae) / h ---0.63 ± 1.26 86. solanum nigrum l. (solanaceae) / h ---2.44 ± 1.31 87. syzygium cumini (l.) skeels (myrtaceae) / t ---0.40 ± 0.48 88. toona serrata (royle) m. roemer (meliaceae) / t ---0.78 ± 1.55 89. urena lobata l. (malvaceae) / u-s ---0.71 ± 0.96 n / pantropics e / north america, mexico n / india, tropical and temperate asia, africa n / india, myanmar, sri-lanka n / india, nepal, bhutan, w. china n / tropical asia, africa n / india, nepal n / india, pakistan, sri-lanka n / india, indo-china n / india, tropical and temperate asia e / southern usa, mexico, central america n / india, malaysia, sri-lanka n / indian subcontinent, china, indo-china e / america n / india, temperate asia n / india e / eurasia n / india, tropicalasia n / india, myanmar e / australia given after family: c for climber, h for herb, s for shrub, t for tree and u-s for under-shrub; species absent; *status based on native and exotic status where; n, e and o stand for native, exotic and obscure status respectively; ± is standard deviation. hederifolia, holoptelea integrifolia and sida cordata. on the other hand, among species which were common to invaded and non-invaded localities, only a few species were growing more luxuriously in invaded localities. 7 table 2. mean number of plant species in terms of climber, herb, shrub, tree and under-shrub among species present in noninvaded, exclusively in non-invaded, commonly in invaded and non-invaded, in invaded and exclusively in invaded localities. habit type in non in invaded common in exclusively in exclusively in invaded both non-invaded invaded localities localities localities localities localities number of climber 9.33 ± 2.52 6.33 ± 0.58 5.67 ± 1.53 5.50 ± 0.71 1.00 ± 1.41 herb 24.67 ± 2.08** 13.00 ± 4.36 10.33 ± 4.73 14.33 ± 3.21** 2.67 ± 0.58 species shrub 8.67 ± 2.08 8.33 ± 3.21 6.67 ± 2.08 2.00 ± 0.00 1.67 ± 1.15 representing plant tree 7.33 ± 2.31* 4.33 ± 0.58 4.33 ± 0.58 3.00 ± 1.73* 0 habit under-shrub 4.00 ± 1.00 2.67 ± 1.53 2.00 ± 1.00 2.00 ± 1.73 0.67 ± 0.58 total species 54.00 ± 7.00* 34.33 ± 2.08 29.00 ± 2.65 25.00 ± 9.17* 5.33 ± 0.58 *significantly different at level p < 0.05** and 0.1* from associated l. camara invaded localities, as estimated by t-test , ± is standard deviation. table 3. percentage of sum of % basal area for all species, sum of frequency for all species, sum of density for all species, sum of abundance for all species in invaded compared with non-invaded localities during four seasons. percentage against non-invaded localities season sum of % basal area sum of frequencies sum of densities sum of abundance covered by all species of all species of all species of all species spring 83.15 70.29 66.25 52.88 summer 74.45 89.64 75.25 88.30 monsoon 73.04 62.98 45.22 75.96 winter 78.42 56.84 49.81 51.75 annual mean 77.27 ± 4.537 69.9 ± 14.2 59.1 ± 14 67.2 ± 17.9 these were martynia annua and cassia tora specifically during summer; euphorbia hirta and cassia occidentalis during summer as well as monsoon seasons; and eragrostis tenella and pyrus pashia throughout the year. in terms of plant habit l. camara invasion seems to have maximum impact on herbs and trees. in comparison to 24.67 ± 2.08 herb species in non-invaded localities there were significantly less, 13.00 ± 4.36 species in l. camara invaded localities (table 2). similarly, compared to 7.33 ± 2.31 tree species in non-invaded localities there were significantly less (4.33 ± 0.58) species in l. camara invaded localities. the trend continued among those species which were exclusive to either invade or noninvaded localities. there were fewer herbaceous and no tree forms among species specific to invaded localities in comparison to species present specifically in non-invaded localities. the values for invaded localities in terms of sum of per cent basal area (secondary growth of stem), sum of frequencies (probability of finding any species), sum of densities (overall density) and sum of abundance (local density) of all species were very low compared to noninvaded sites (table 3). the negative impact of l. camara on local flora is illustrated by the lower percentage values for invaded localities in terms of various parameters mentioned above varied with different seasons. the annual mean value of overall basal area of all plants from invaded localities was 77.27 ± 4.54% of non-invaded localities. it was lowest (73.04%) during winter and highest (83.15%) during spring. the sum of frequencies of all species in invaded localities was reduced to 69.9 ± 14.2% of noninvaded localities (table 3). thus, with changing seasons there were some large fluctuations in impact of l. camara invasion on probability of finding any plant species. the maximum negative impact was found during winter season, when overall frequency of finding any species in invaded localities was reduced to just 56.84% compared to non-invaded localities. relatively lesser negative impact was observed during summer, when frequency for invaded localities was 89.64% of non-invaded ones. overall density of plant species in invaded localities was just 59.1 ± 14% of noninvaded localities; it was most negatively affected feature of plant distribution in invaded localities. the impact on density was most severe during monsoon followed by winter when overall density of plants in invaded localities was reduced to nearly half of corresponding non-invaded localities. similarly, overall abundance of all species from invaded localities was very low; it was 67.2 ± 17.9% of non-invaded localities (table 3). among all parameters mentioned above, overall value of basal area demonstrated a comparatively lesser impact of invasion. however, this was not the case if the 8 p e r c e n t v a lu e s o f e x o ti c a g a in s t n a ti v e s p e c ie s 300 b 280 260 240 220 200 180 160 140 120 100 80 ab ab ab 60 ab 40 a 20 a b c d e f specific group figure 2. percentage of exotics in relation to native species present in non-invaded (a), exclusively in non-invaded (b), commonly in invaded and non-invaded (c), exclusively in invaded (d), in invaded localities (e) and in whole area under study (f) . means denoted by different alphabets are significantly different at p < 0.1, as estimated by tukey-test, ± is standard deviation. basal area of l. camara is excluded from the analysis. in invaded localities l. camara had about 62.9 ± 0.86% contribution in total basal area of all species. thus, although the total basal area of plants present in invaded localities was 77.27 ± 4.54% of non-invaded localities, this was mainly due to l. camara. the contribution of other plants was very low, that is, 37.42 ± 0.8% of noninvaded localities. similarly, l. camara also had maximum (29.81 ± 3.1%) share in total ivi for invaded localities. after incorporating data on the exotic and native status of each species found during the present study, l. camara was found to have some relation with exotic and native status of species. there were 27% exotics among the flora of nayar irrespective of invaded or non-invaded localities. however, the percentage of exotics was found to vary when plants in this region were divided into different subsets on the basis of their presence and absence in invaded and non-invaded localities. it was 30, 19.35 and 50% among species common to invaded and non-invaded localities, species specific to non-invaded localities and species specific to l. camara invaded localities respectively. during this survey the overall number of exotics was found to be 43.8 ± 8.1% of the native species (figure 2). the exotic to native species ratio was particularly high (60.3 ± 7.2%) in the invaded localities, compared to (39 ± 9.6%) for non-invaded localities. the share of exotics among those species which were present exclusively in noninvaded localities was 26 ± 4.4% of native species. this was very low in comparison to overall per cent of exotics against natives. however, among those species which were restricted exclusively to l. camara invaded localities there were extremely high percentage (155.5 ± 126.2) of exotics in relation to native species. the exotic to native ratio were significantly different in case of species those were exclusive to noninvaded localities and those were restricted to invaded localities. exotic species had 63.78% share in total basal area cover of invaded localities. it was extremely high in comparison to 3.55% for non-invaded localities. the percent share of exotics in overall frequency of occurrence of plant species in invaded localities (33.82%) was also higher compared to 26.83% for non-invaded localities (figure 3). exotics also constituted a higher percentage of total density of plants in invaded localities, although the trend was reversed in the case of abundance. the percentage of exotics in total ivi of invaded localities (44.38), that was nearly equal to per cent share (52.02) of noninvaded localities, also indicated that exotics were 9 p e r c e n t s h a re v a lu e m ea n of in to ta l a n n u a l 100 * exotic native obsecure 90 80 * 70 * 60 50 40 30 * 20 10 * 0 i. n.i. i. n.i. i. n.i. i. n.i. i. n.i. basal area frequency density abundance i.v.i. parameters under study in lantana camara invaded (i.) and non-invaded (n.i.) localities figure 3. percentage of species with exotic, native and obscure origin, in terms of basal area, frequency, density, abundance and ivi. mean values for invaded localities with asterix (*) above bar are significantly different from corresponding non-invaded localities at p < 0.05, as estimated by tukey-test, ± is standard deviation. occupying very important places in l. camara invaded localities (figure 3). the species richness and diversity of invaded localities was very low in comparison to noninvaded localities. the difference was extremely high and significant in terms of species richness (table 4). in terms of diversity, however, there was not a very large difference between the two compared localities. despite this, the diversity of invaded localities was significantly lower than that of noninvaded localities in terms of fisher's diversity index ( ), shannon’s index (h'), and hills number (n1). the difference was neither very large and nor statistically significant in terms of simpson's index ( ) and hills number (n2). despite having lower values of diversity, the invaded localities had nearly equally even distribution of diversity (as shown by evenness e1 and e2) to that of non-invaded localities (table 4). discussion l. camara has serious deleterious effect on some of endemic animal (morton, 1994; sharma et al., 2007) and plant species. it is also known to displace natural scrub communities as well as prevent natural regeneration of some tree species (ambika et al., 2003; sharma and raghubanshi, 2006; dobhal, 2010). in shivalik hills in northwestern himalayan range of india, it was observed that the diversity, evenness and richness of the native species were drastically reduced in the forest invaded by the exotics (dogra et al., 2009a,b). similar patterns were observed in the case of riparian forests along the nayar river, where a decrease of nearly 30% in species richness was recorded in l. camara invaded localities. compared to non-invaded localities there were significantly fewer herb and tree species in l. camara invaded localities. specially, there were no tree species among species found exclusively in invaded localities. plant species with specific root and shoot distribution habits in relation to l. camara may come across different level of resource competition and allelopathic inhibition offered by this invasive (dobhal et al., 2010). this could also be a plausible reason for observed variation in impact of l. camara invasion on different life forms. anthropogenic and natural disturbances act together to facilitate the introduction and spread of exotic species in riparian zones. further, the availability of moisture and the dispersal of propagules by water may increase invasibility of riparian zones (hood and naiman, 2000; pysek and prach, 1994) . in riparian zones between hill slopes, such as in nayar region where more than 25% of total species were exotics, there can be concentrated energy and material flow during flooding and other geomorphic disturbances and riparian forest communities 10 table 4. values of different parameters associated with richness and diversity in l. camara invaded and non-invaded localities. locality type parameters associated with species richness and diversity and distribution non-invaded l. camara invaded richness diversity distribution of diversity (evenness or equitability) number of species (n0) 31.50 ± 6.24** 22.00 ± 4.07 peet index (p) 842.35 ± 291.59** 451.47 ± 165.01 1. margalef index (r1) 3.50 ± 0.53** 1.11 ± 0.14 2. menhinick index (r2) 4.68 ± 1.22* 0.78 ± 0.16 fisher's diversity index ( ) 6.87 ± 1.30** 5.05 ± 0.84 shannon’s index (h') 2.61 ± 0.32** 2.36 ± 0.32 simpson's index ( ) 0.12 ± 0.05 0.14 ± 0.06 hills number n1 14.29 ± 4.42** 11.07 ± 3.56 hills number n2 9.91 ± 3.71 8.11 ± 3.19 evenness e1 0.76 ± 0.07 0.77 ± 0.07 evenness e2 0.45 ± 0.09 0.50 ± 0.10 *significantly different at level p < 0.05** and 0.1* from associated l. camara invaded localities, as estimated by t-test, ± is standard deviation. use material trapped by these disturbances (junk et al., 1982; nakamura and inahara, 2007). in this region exotics had a higher percentage share in total density of plants in invaded localities, but the trend was reversed in the case of abundance. higher percentage values of exotics in total abundance of non-invaded localities indicated that in non-invaded localities, exotics were mostly restricted to small abundant patches, whereas they were distributed densely throughout in the area invaded by l. camara. further, there was a significantly higher proportion of exotics among species found exclusively with l. camara against species present exclusively in non-invaded localities, indicating that l. camara facilitates the invasion of other exotics. it appears that l. camara invasion sweeps over native flora and promotes the establishment of other exotic species. thus, there was a possibility that in near future exotics may cover larger areas of the region in comparison to endemics, as l. camara infestation continues increasing without any barrier. the increase in the ration of exotic to endemic species in nayar region becomes crucial as this region is a part of garhwal-kumaon himalayas (uttarakhand), one of 25 micro-endemic centers in india (subramani et al., 2005). basal areas and density of plants of a species, respectively, provide simple indicators of growth and survival rates of a species. in invaded areas there was lower basal area of plants, of which l. camara had most of the share; besides this there was decrease in the overall number of species, the number of individuals per species, and overall density. there were also lower chances of frequent occurrence of any species in invaded localities compared to associated non-invaded ones. in total there was significantly lower richness and diversity and overall health of plants in invaded localities compared to non-invaded ones. this may be attributed to thick monoculture of l. camara that alter the microenvironment (light, ph and temperature) beneath the l. camara thickets, and inhibit either germination or growth of other species (sharma and raghubanshi, 2007). although riparian zones can act as a buffer against fire and act as a refuge for fire-sensitive species, under some circumstances, like dry climate and the accumulation of dry fuel, riparian areas become corridors for fire movement. fires in riparian zones create canopy gaps and drier conditions, which allow establishment of fire adapted species (pettit and naiman, 2007). increased dominance of a fire loving species like l. camara in such an important buffer zone may have far reaching consequences on native riparian ecosystem. there may be a positive feedback between fires and invasion by l. camara, leading to a fire l. camara cycle that can have deleterious compositional and functional consequences for forest ecosystems (hiremath and sundaram, 2005, dobhal et al., 2009). being a complex process it is difficult to evaluate the effect of an invader on fire regimes (strayer et al. 2006). however, reports of significant increase in l. camara seed germination in smoke (raizada and raghubanshi, 2010) and enhanced prolification after fire (gentle and duggin, 1997; dobhal et al., 2009) supports the view given above. conclusions l. camara poses a threat to local flora. the number, density and frequency and overall health of species were remarkably poor in invaded areas. though it is premature to say, it seems that l. camara favours exotics over 11 endemic species. however, more studies are required to further investigate this relationship. further, due to its inflammable nature and dominance in regional flora, l. camara is a potential threat to riparian zones that can act as a buffer against fire and act as a refuge for firesensitive species. consequently, beside individual species and life forms such as trees and herbs, the entire forest ecosystem itself is under threat due to l. camara invasion. it requires the immediate committed attention of ecologists, conservationists and policy makers. acknowledgements authors are thankful to university grant commission (india), for providing financial assistance. we also admire the help provided by botanical survey of india (dehradun) and panjab university (chandigarh) in identification of various plant species. thanks are also due to the anonymous reviewers, for their valuable suggestion for improving overall presentation, particularly the language of this manuscript. references ambasht rs (1990). a textbook of plant ecology. student’s friends and co., varanasi, india, p. 373. ambika sr, poornima s, palaniraj r, sati sc, narwal ss (2003). allelopathic plants. 10. lantana camara l.. allelopathy j., 12(2): 147162. barbour mg, burk jh, pitts wd, gilliam fs, schwartz mw (1999). terrestrial plant ecology. 3rd edition. addison wesely longman inc., menlo park, 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