1_Kertesz-Krecek.indd 201Kertész, Á. and Křeček, J. Hungarian Geographical Bulletin 68 (2019) (3) 201–221.DOI: 10.15201/hungeobull.68.3.1 Hungarian Geographical Bulletin 68 2019 (3) 201–221. Introduction The degradation of land and of landscapes is one of the most severe problems of the Earth. The concept of land degradation originates from soil degradation and it is often used as a synonym for soil degradation. Landscape degradation means much more than just the degradation of the uppermost layer of the Earth’s crust. The landscape is understood as a synthesis of landscape forming factors, therefore the decline of one or more land- scape forming factors leads to the degrada- tion of the landscape as a whole. According to Imeson, A. (2012) roughly 20 per cent of global land area is presumably already de- graded. The consequence is a persistent de- cline in land productivity and in the provi- sion of other ecosystem services. The terms “landscape degradation” and “land degrada- tion” will be used alternatively with the same content in this paper. Global environmental change and land degradation A short review of the processes of envi- ronmental change from the aspect of land degradation will be provided below. Global 1 Geographical Institute, Research Centre for Astronomy and Earth Sciences, Hungarian Academy of Sciences. H-1112 Budapest, Budaörsi út 45. E-mail: kertesza@iif.hu 2 Department of Hydrology, Czech Technical University in Prague. Thákurova 7, CZ-166 29 Prague 6. E-mail: josef.krecek@fsv.cvut.cz Landscape degradation in the world and in Hungary Ádám KERTÉSZ1 and Josef KŘEČEK 2 Abstract The concept of landscape degradation interprets the process in landscape ecological sense, i.e. the degrada- tion of one landscape forming factor leads to the degradation of the whole landscape. The consequence is a persistent decline in land productivity and in the provision of other ecosystem services. Global environmental change is driven mainly by human influence in the Anthropocene with an exponentially growing significance in time. Global environmental processes are very much interrelated. Because of population growth more food, fibre, clean water, energy etc. will be needed and there are two ways to achieve this, either to gain new areas for cultivation by changing present land use or to intensify cultivation in the areas with the best conditions for cultivation. Deforestation and forest degradation are dealt with in detail in the paper. The introduction of soil degradation processes follows the system given in the EEA Environmental Assessment Report (2003). The effect of landscape degradation on ecosystem services is well explained by the fact that approximately 20 per cent of the Earth’s vegetated surface shows persistent declining trends in productivity, mainly as a result of land/water use and management practices (UNCCD 2017). Landscape degradation processes of Hungary are discussed in the paper, including sheet, gully and wind erosion, soil sealing, salinization, physical degra- dation, landslides, desertification. An estimation of the aesthetical value of the landscape is provided as well concluding that the surface of the country represents a relatively high aesthetical value. The main conclusion is that Hungarian landscapes are well maintained and they belong to the most precious European landscapes. It should be added that all degradation processes represent important environmental problems to be combat- ted on the basis of a well-established policy making. Keywords: land degradation, landscape degradation, desertification, global environmental change Kertész, Á. and Křeček, J. Hungarian Geographical Bulletin 68 (2019) (3) 201–221.202 environmental change has accompanied the whole history of the Earth. The triggering factors of the changes over the last 200 years, especially recent changes are mainly due to human activities. These changes are different from those of natural origin. Anthropogenic changes driven by human activities are very significant for the structure and function of ecosystems to the Earth system, with equally far-reaching consequences for human well- being (Turner, B.L. et al. 2008). The processes of global environmental change are so much interrelated that it is difficult to separate them and report exclusively on a single process. Population growth World population in 2019 is 7.7 billion people and it is expected to be almost 10 billion peo- ple by 2050 (World Population Clock 2019). The urban population in 2019 is about 4.26 billion, i.e. 55 per cent of the total population in the world. It should be mentioned that the rate of global population growth is declining. The current growing rate (2018–2019) is 1.07 per cent per year, less than in 2017 (1.09% per year) and in 2016 (1.14% per year). The regional distribution is as follows: Asia 59.4 per cent, Africa 17.1 per cent, Europe 9.6 per cent, Latin America and the Caribbean 8.5 per cent, North America 4.8 per cent, Aus- tralia and Oceania 0.5 per cent. The share of the developing world is 85.6 per cent. Analysing the data from the aspect of land- scape degradation it is obvious that – the constantly growing population even at a lower growth rate will require more food, fibre, clean water, energy etc. and there are two ways to achieve this, either to gain new areas for cultivation by chang- ing present land use, or to intensify cultiva- tion in the areas with the best conditions for cultivation; – the huge percentage of urban population means an increase of sealed area, water and air pollution, a growing amount of waste etc.; – the population percentage of the devel- oping world makes a huge impact on the developing countries from various aspects including landscape degradation and it triggers an ever growing trend of migra- tion from these countries. Climate change Although climate change has been happen- ing throughout the Earth’s history as a con- sequence of natural causes, recent changes of the climate are mainly due to human activi- ties. The sources of human-released green- house gases are well known. They originate from emissions associated with energy use, but on local and regional scales, urbaniza- tion and land use changes are also impor- tant. “These changes will be increasingly manifested in important and tangible ways, such as changes in extremes of temperature and precipitation, decreases in seasonal and perennial snow and ice extent, and sea level rise” (Carl, T.R. and Trenberth, K.E. 2003). The main anthropogenic activities related to the emission of green-house gases before the industrial revolution were irrigation and de- forestation (Turner, B.L. et al. 2008). The IPCC special report informs about the impacts of global warming of 1.5 °C above pre-industrial levels (IPCC 2018). Climate models project big differences in regional climate characteristics between present-day and global warming of 1.5 °C, and between 1.5 °C and 2 °C. The differences are as follows: increases in mean temperature in most land and ocean re- gions (high confidence), hot extremes in most inhabited regions (high confidence), heavy precipitation in several regions (medium confidence), and the probability of drought and precipitation deficits in some regions (medium confidence, IPCC 2018). From the aspect of landscape degradation temperature increase, precipitation decrease and the augmenting risk of the intensity and frequency of droughts and high intensity rainfall events, i.e. increases in frequency, 203Kertész, Á. and Křeček, J. Hungarian Geographical Bulletin 68 (2019) (3) 201–221. intensity, and/or amount of heavy precipi- tation, as well as other climate and weather extremes point to the possible acceleration of land degradation and desertification process- es in some regions of the Earth. Risks from droughts and precipitation deficits are pro- jected to be higher at 2 °C compared to 1.5 °C of global warming in some regions (medium confidence, IPCC 2018). Climate change is a major factor influenc- ing desertification processes, the global im- portance of desertification will increase and it is and it will be the most important group of land degradation processes in those re- gions of the world where the climate is arid, semi-arid or dry sub-humid. Land use change Up to the end of the 20th century 50 per cent of the Earth’s ice-free land surface has been transformed and much of this change is a di- rect consequence of land use type (Turner, B.L. et al. 2008). Landscape change is one major characteristic of recent environmental change across Europe (Lundberg, A. 2018). The use of land in order to yield goods and services represents the most substantial hu- man alteration of the Earth’s system. Human use of land changes the structure and func- tioning of ecosystems, and it alters how eco- systems interact with the atmosphere, with aquatic systems, and with surrounding land (Vitousek, P.M. et al. 1997). Land Use and Land Cover Changes (LULCC) are strongly connected to other processes of global change, especially to cli- mate change, population growth and land degradation. Land use/land cover changes are responsible for 35 per cent of human-in- duced CO2 equivalents (Foley, J.A. et al. 2005) pointing to the relationship with climate change. As discussed above, the increasing need for food requires new fields for agri- cultural production. The new agricultural areas in most cases replace former forests. If the forest is cut land degradation will take place. If agricultural areas already in use are used more intensively, land degradation will increase as well. In addition to the increase of the areas used for agriculture, urban and industrial areas are growing, too. Urban intensification is accompanied by large increases in resource consumption, habitat fragmentation and bio- diversity loss (Foley, J.A. et al. 2005; Lawler, J.J. et al. 2014; Kertész, Á. et al. 2019). The global expansion of agricultural, ur- ban and industrial areas was accompanied by large increases in energy, water, and fertilizer consumption and they potentially undermine the capacity of ecosystems to sus- tain food production, maintain freshwater and forest resources, regulate climate and air quality, and ameliorate infectious diseases (Foley, J.A. et al. 2005). Landscape degradation Land degradation and landscape degrada- tion research have become extremely im- portant during the past decades. According to Barrow land degradation can be defined “as the loss of utility or the reduction, loss or change of features or organisms which can- not be replaced” (Barrow, C.J. 1991). The land is degraded when “it suffers a loss of intrinsic qualities or a decline in its capabili- ties” (Blaikie, P. and Brookfield, H. 1987). The UNEP (1992) definition emphasizes the reduction of the potential of natural re- sources as a result of processes acting in the landscape. Johnson, D.L. and Lewis, L.A. (1995) un- derlined the role of human interventions in land degradation and focused on the reduc- tion of biological production and/or the util- ity of an area. Land degradation means the reduction or loss of biological productivity and the nega- tive effects on the functioning of the land and the related ecosystems (Hudson, P.F. and Alcántara-Ayala, I. 2006). In this paper the terms of land and landscape degradation will be used with the same meaning, i.e. meaning landscape degradation. Kertész, Á. and Křeček, J. Hungarian Geographical Bulletin 68 (2019) (3) 201–221.204 According to the Intergovernmental Platform on Biodiversity and Ecosystem Services “degradation of the Earth’s land surface through human activities is nega- tively impacting the well-being of at least 3.2 billion people, pushing the planet towards a sixth mass species extinction, and costing more than 10 per cent of the annual global gross product in loss of biodiversity and eco- system services. Loss of ecosystem services through land degradation has reached high levels in many parts of the world, resulting in negative impacts that challenge the cop- ing capacity of human ingenuity. Groups in situations of vulnerability feel the greatest negative effects of land degradation, and of- ten experience them first. These groups also see the greatest benefits from avoiding, re- ducing and reversing land degradation. The main direct drivers of land degradation and associated biodiversity loss are expansion of crop and grazing lands into native vegeta- tion, unsustainable agricultural and forestry practices, climate change, and, in specific ar- eas, urban expansion, infrastructure develop- ment and extractive industry.” (IPBES 2018). The IPBES definition for degraded land is as follows: “degraded land is a state of land which results from the persistent decline or loss in biodiversity, ecosystem functions and services that cannot fully recover unaided within decadal time scales. Land degradation is a myriad of processes that drive the decline or loss in biodiversity, ecosystem functions or services, and includes the degradation of freshwater and coastal ecosystems which are closely interconnected with terrestrial eco- systems”. There are various estimations on the per- centage of degraded land ranging between 20 and 75 per cent (see the Introduction). The most recent data published in the World Atlas of Desertification (Cherlet, M. et al. 2018) are as follows: over 75 per cent of the Earth’s land area is already degraded, and over 90 per cent could become degraded by 2050. Globally 4.18 million km² is degraded annually, with Africa and Asia being the most affected. Deforestation (forest area change) and forest degradation Forest degradation Deforestation as one of the most important and most dangerous global processes will be presented in detail below. The degradation and devastation of forests is a very serious problem as well. (a) Environmental services of forests. Generally, forests are considered making vital contributions both to people and the planet, conserving biodiversity, soil and wa- ter, and responding to climate change (FAO, 2018). The majority, 76 per cent of the global forest area are public forests with a perspec- tive of sustainable management. Willis, K.G. (2002) categorised the main non-mar- ket costs and benefits of forestry practices in headwater catchments, where the principal products include: (1) abstraction for potable water (for drinking and commercial uses), (2) agriculture and irrigation in down-stream areas, (3) hydro-electric power generation, (4) wildlife (including recreational and com- mercial fisheries), and (5) other recreational uses. According to the data of FAO (2018), the global percentage of forests managed for soil and water protection is 25 per cent: the highest in North and Central America (71%), 12 per cent in Europe, and the lowest in Africa (8%). Forest degradation is defined as a reduction in the capacity of ecosystem services as a result of anthropogenic and environmental changes, and, the presence of soil erosion is a prime indicator of forest degradation (FAO, 2011). (b) Regional drivers of forest degradation. Although the reduction of the global forest area stopped recently (UNFF, 2017; FAO, 2018); 30 per cent of global forest cover has been cleared and another 20 per cent degrad- ed losing their capacity to provide services to people and nature, most of the rest has been fragmented, leaving only about 15 per cent intact. Overall, agricultural use is responsi- ble for around 80 per cent of deforestation worldwide; concerning the developing coun- 205Kertész, Á. and Křeček, J. Hungarian Geographical Bulletin 68 (2019) (3) 201–221. tries (Hosonuma, N. et al. 2012); commercial agriculture is the most important driver in Latin America (68% contrary to around 35% in Africa and Asia) while the effects of local agriculture are equally distributed among the continents (27–40%). IUCN (2017) re- ported that over half of the tropical forests have been destroyed since the 1960s by the conversion of forest to agriculture land. In Europe, forests cover 38 per cent of the land area (EEA, 2007 – Figure 1): about three quarters of them are considered ‘un- disturbed’ (mostly located in the Russian Federation). The devastating pressure on European forests is caused particularly by air pollution (mainly in Central and Eastern Europe), and fire (which is a major concern in Southern Europe). On average 700,000 hectares of wooded land in Europe are burnt each year by a total of 60,000 fires (FAO, 2011). According to (EEA, 2017), the most harmful air pollutants in terms of damage to forests are ozone (O3), ammonia (NH3) and nitrogen oxides (NOx). However, 3.7 million hectares of Europe’s forests were damaged by acid rain impacts initiated by sulphur emissions culminating in the middle of the 1980s. The exceedance of acidity critical loads in 2000 is shown in Figure 2. In 2014, transboundary air pollution exceeded the critical level for the protection of forests over 68 per cent of the total EU–28 forest area (EEA, 2017). The acid rain calamity in the ‘European Black Triangle’ (the border area of the Czech Republic, Germany and Poland) lead to an extended commercial harvest of spruce plantations (Picea abies) replaced by Junco effusi-Calamagrostietum villosae community with dominant grass cover (Křeček, J. and Hořická, Z. 2006). In 1982 and 2015, ef- fects of forest clear-cut were studied in the Jizerka experimental catchment (the Jizera Mountains, Czech Republic). Skidding the timber by wheeled tractors caused 10.3 per km of skid trails and the drainage density increased from 1.45 to 7.55 per km (Figure 3). On the harvested runoff plots, not affected by skid trails, the loss of soil 0.007–0.014 mm per year was comparable with undisturbed forests. But, the eroded soil in skid trails reached 6.17 mm (61.73 m3 per ha) by harvesting 23,882 m3 of timber (i.e. 0.25 m3 per m3 of harvested timber). At the catch- ment outlet, sediment yield reached 25 per cent of the eroded soil. Natural regeneration of erosion rills was supported particularly by the development of herbaceous vegetation. Fig. 2. European exceedance of critical acidity loads in 2000. Source: EEA (2017). Fig. 1. European forest cover (light yellow 0–5%, dark green > 60%). Source: EEA (2007). Kertész, Á. and Křeček, J. Hungarian Geographical Bulletin 68 (2019) (3) 201–221.206 In 2003, twelve years after the logging, only 1.5 km (15%) of active deeper rills were still identified (Křeček, J. et al. 2017a). Forest conservation and recovery About 7 per cent of the European forest area is under protection and about 3 per cent under strict protection. Nature-based solu- tions for managing forests for soil and water protection and forest landscape restoration can reverse the effects of deforestation and degradation and regain the ecological, social, climatic and economic benefits of forests. But, due to the complex nature of forests, the ecosystem services they provide, especially water-related services are often misunder- stood, undervalued, and therefore over- looked (Křeček, J. et al. 2017b). In the near future, dominant spruce stands in mountain catchments will be endangered by impacts of the global climate change (increasing global temperatures by 1.4–5.8 °C till 2100) (EEA, 2003; Christensen, J.H. 2005) as well as by more frequent floods and draughts. The risks of climate change will be considerably higher and less manageable in those countries which already suffer significantly from drought stress such as the Mediterranean countries. Soil degradation Land degradation and climate change are es- timated to lead to a reduction of global crop yields by about 10 per cent by 2050. In India, China and sub-Saharan Africa land degrada- tion could bisect crop production. By 2050, up to 700 million people are estimated to have been displaced due to issues linked to scarce land resources. The figure could reach up to 10 billion by the end of this century (Cherlet, M. et al. 2018). Future land degradation will be, of course, different in various parts of the world. According to Crosson, P.R. (1997) an accelerat- ing rate of degradation (0.4%) can be assumed for the coming 30 years, accompanied by a de- cline of altogether 17 per cent of agricultural activity. Land degradation will not be a serious threat to food supply because this supply will come from the non-degrading lands. In soil science the terms “land degrada- tion” and “soil degradation” are often used with the same meaning. Soil degradation processes belong to land and landscape degradation processes because the degrada- tion of the soil leads to the degradation of all landscape forming factors (see Introduction). In the EEA Environmental Assessment Report (2003) the following soil degradation Fig. 3. Drainage network and erosion rills in the Jizerka catchment before (1983) and after the forest harvest (1990, 2003). Source: Křeček, J. et al. (2018). 207Kertész, Á. and Křeček, J. Hungarian Geographical Bulletin 68 (2019) (3) 201–221. processes are mentioned, with special em- phasis on European soils: (1) Soil sealing. It is a unique and very im- portant harmful process as the result of soil sealing is the isolation of the soil from the atmosphere, hydrosphere and the biosphere. The soil is covered by an impervious mate- rial. The areas affected are settlements and transportation infrastructures. One of the most significant consequences is that the wa- ter on sealed surfaces is running off without any filtration with an increased speed and in great quantities. Sealed surfaces are lost to other land uses (e.g. agriculture and forestry). Ecological soil functions, e.g. carbon storage and habitat for unique biota are limited or hampered. Soil sealing can lead to habitat fragmentation and to the disruption of migration corridors for wildlife species. (2) Soil erosion by water and wind. As every degradation process, soil erosion has also been exacerbated by human activities, espe- cially by the extension of agriculture to the hilly, sloping areas and so soil erosion can be regarded as one of the major and most widespread forms of land degradation. According to Oldeman, L.R. et al. (1991) about 17 per cent of the total land area in Europe is affected by soil erosion to some ex- tent. According to Eurostat (2018), based on a study performed by Joint Research Centre, approximately 11.4 per cent of the EU terri- tory is estimated to be affected by moder- ate to high level soil erosion rate (more than 5 tons per ha per year). A previous assess- ment estimated the percentage of the area affected by soil erosion at 16 per cent (EEA, 2003). The explanation for this reduction is due to the application of management prac- tices against soil erosion. Mean rates of soil erosion by water amounted to 2.4 tons per ha per year. The total annual soil loss in the EU is estimated at 950 megatons (Eurostat, 2018). Unsustainable agricultural practices, the lack of measures against soil erosion in some areas, large-scale farming, overgrazing, poor water management and forest fires in the Mediterranean region are the most signifi- cant influencing factors of soil erosion. In Europe soil erosion by water acts on about 92 per cent of the total area affected by ero- sion. Wind erosion is less important and it is localized to some areas of Western, Central and Eastern Europe. It should be mentioned, however, that wind erosion played an ex- tremely important role in the establishment of the Soil Conservation Service of the United States in the 1920s. Land degradation is accompanied by a negative effect on productivity. According to Pimentel, D. et al. (1993) soil erosion caus- es 15–30 per cent less production. Nutrient depletion because of erosion leads to 29 per cent decline of crop production and 19 per cent loss in total production. An additional negative effect is yield reduction (e.g. yield reduction in Africa due to past soil erosion may range from 2 to 40 per cent, with a mean loss of 8.2 per cent for the continent (Eswaran, H. et al. 1999). The relationship between erosion and productivity can be ex- pressed by a negatively-exponential curve, i.e. production diminishes very rapidly in the early stages of erosion. Different soil types show, of course, different patterns (Tengberg, A. and Stocking, M. 1997). (3) Soil contamination from non-point (dif- fuse) and point sources causes damage of sev- eral soil functions and the contamination of groundwater and surface water. The main non-point sources of soil contamination are the deposition from runoff, surface waters and from the eroded soil, atmospheric depo- sition (acidification and eutrophication com- pounds, fertilizers, pesticides, sewage sludge and manure which may contain heavy met- als, too). Contamination from point sourc- es can originate from industrial plants no longer in operation, municipal and indus- trial waste disposals and former industrial accidents (EEA, 2003). Operating industrial plants and mining sites are a contamination risk for soils and groundwater. (4) Salinization, i.e. the accumulation of wa- ter-soluble salts near the soil surface is an im- portant soil degradation process in Europe. Saltwater intrusion in the Mediterranean and Kertész, Á. and Křeček, J. Hungarian Geographical Bulletin 68 (2019) (3) 201–221.208 inland salinization mainly in Eastern and South Eastern Europe as well as secondary salinization due to the application of salt rich irrigation water lead to unproductive soils and other environmental problems. The lat- ter points to the role of human society mainly by inappropriate irrigation practices. The area affected by salinization is estimated to cover 3.8 million ha in Europe (EEA, 1995). The global estimate of the area made unus- able by secondary salinization is 1 million ha in a year. In advanced stages salinization may lead to the extirpation of vegetation and to transforming fertile land to barren and the end of the process can be desertified land. (5) Soil compaction is mainly the conse- quence of the repetitive and cumulative ef- fect of heavy machinery. Soil compaction decreases infiltration, increases surface run- off and leads to accelerated water erosion accompanied by the loss of topsoil and nu- trients. Biochemical and microbiological ac- tivities will change, too. Topsoil compaction can be easily handled while subsoil compac- tion is persistent and difficult to be reversed. The first global survey of land (soil) degra- dation, GLASOD (Global Assessment of Soil Degradation) was performed by Oldeman, H. et al. (1991). It contains the extension of various forms of soil degradation (water and wind erosion, chemical and physical degradation), the rate of degradation (light, moderate, strong, extreme) and the causes of degradation (deforestation, overgrazing, im- proper farming, overexploitation, contamina- tion). According to this survey 3.7 per cent of the Earth’s surface is affected by physical and chemical degradation and 12 per cent by water and wind erosion. According to Oldeman, H. et al. (1991) 38 per cent of the agricultural area of the Earth is degraded. The percentage of degraded are- as in Africa is 65 per cent, in Central America 74 per cent and in South America 45 per cent. The proportion of degraded pasture and for- ests is smaller (21% and 18%, respectively). Considering agricultural area, permanent pasture and forests together, the percentage of degraded area is 23 per cent. Land degradation and ecosystem services Ecosystem services are “the benefits people obtain from ecosystems” (Millennium Eco- system Assessment, 2006). The four catego- ries of ecosystem services are as follows: – supporting services provide the basic con- ditions for life, e.g. fertile soils; – regulating services provide the function- ing of ecosystems, e.g. flood and decease control; – provisioning services belong to the third group (e.g. food, water, fuel, wood); – the cultural services include e.g. recre- ational, cultural benefits. Because of the significance and critical state of ecosystem services an international platform was created: The Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) which is an intergovernmental body on the state of biodiversity and of the ecosystem services. The Millennium Ecosystem Assessment (Millennium Ecosystem Assessment, 2006) preceded IPBES. The thematic assessment of land degradation and restoration is deliver- able 3(b)(i) of the IPBES working program (IPBES, 2019). According The Global Land Outlook a sig- nificant proportion of managed and natural ecosystems are degrading: over the last two decades, approximately 20 per cent of the Earth’s vegetated surface shows persistent declining trends in productivity, mainly as a result of land/water use and management practices (UNCCD 2017). Land degradation reduces the quality of land in multiple ways. Improper land use leads to long-term losses of ecosystem function and productivity. Desertification The term of desertification was first men- tioned in the 1920s (Bovill, E.W. 1921, cited by Herrmann, S.M. and Hutchinson, C.F. 2005) when the extension of the West African Sa- hara into the Sahel zone was first observed. Aubreville used the term first (Aubreville, 209Kertész, Á. and Křeček, J. Hungarian Geographical Bulletin 68 (2019) (3) 201–221. A. 1949) describing the change of produc- tive land into a desert (Herrmann, S.M. and Hutchinson, C.F. 2005). This statement indi- cated that the term desertification is always connected with human activities, with land mismanagement. Drylands have a huge extension covering approximatively 40 per cent of the Earth surface. Because of the significance of dry- lands, it seemed to be appropriate to define a special group of land degradation processes. In 1977 after a series of extremely arid peri- ods in Sahelian Africa UNCOD organized a conference (United Nations Conference on Desertification) in Nairobi. According to the United Nations Intergovernmental Convention to Combat Desertification “Desertification means land degradation in arid, semiarid and dry sub-humid areas resulting from various factors including climate variation and human activities” (UNCOD, 1977). The threshold values of the given climatic zones are defined by the FAO-UNESCO (1977) bioclimatic index: P/ETP (precipitation/potential evapotranspi- ration, see e.g. Kertész, Á. 2009). The UNCOD definition interprets deserti- fication as a process leading to desert devel- opment. This definition concentrates mainly on marginal zones surrounding deserts, like the Sahara–Sahel marginal belt. It should be kept in mind, however, that the process of desertification may not lead to desert de- velopment. Proper management can stop and may reverse the process. All concepts agree upon the fact that desertification means severe degradation problems of territories with water deficits and ongoing aridification (Kertész, Á. 2009). Desertification occurs also in other climate zones (e.g. associated with salinization). If the land is properly managed drought doesn’t lead to desertification, not even under arid climatic conditions. Desertification is the re- sult of a combination of drought with land mismanagement (Le Houérou, H.N. 1996). Desertification processes affect 42 million km2 (33% of the Earth’s land surface – Eswaran, H. and Reich, P. 1998) and some 1 billion peo- ple. According to recent data published by IFAD (2016) about 40 per cent of Earth’s land is covered by drylands, and these areas are home to over 2 billion people. There is uncertainty about the areal extent of desertification. Reynolds, J.F. et al. (2003) report that up to 70 per cent of all drylands are ‘desertified’; others suggest that the fig- ure is no more than 17 per cent. 37 per cent of global population live on either potentially, or actually degraded land (Gisladottir, G. and Stocking, M. 2005). The word „desertification” suggests the gradual disappearing of vegetation and in reality the primary cause of desertification is the removal of vegetation by human ac- tivities like deforestation, overgrazing etc. Drought conditions as a result of global warming trigger the sustained growth of vegetation as well. The consequence of veg- etation removal leads to the change of the near surface climate leading to surface in- duration and crusting and hindering infil- tration. As a result, soil erosion rates will in- crease. The upper soil layers, rich in humus and nutrients will be removed and impede the re-establishment of vegetation and the use of the land for agriculture. The rate of desertification depends also on initial soil moisture content and human in- terventions, and the latter can be a positive interference. The course and consequences of the process are clear, from the initial status (i.e. sub-humid, semi-arid or arid conditions) proceeding sequentially through the stages (e.g. if the area in question had a sub-humid climate, then undergoing transformation to semi-arid and then arid conditions). As a consequence of ongoing aridification the area may become hyper-arid. In terms of vegeta- tion, steppe will turn into savannah, followed by thorny savannah and then into semi-de- sert, reaching the ultimate stage of a desert. Landscape degradation in Hungary Land degradation is strongly related to hu- man impact including agricultural activities. Kertész, Á. and Křeček, J. Hungarian Geographical Bulletin 68 (2019) (3) 201–221.210 This statement applies especially for those countries where agriculture still has a consid- erable contribution to the national economy like in Hungary. According to the data of the Hungarian Central Statistical Office the per- centage of the population employed in agri- culture is still relatively high, i.e. 10.97 per cent in 2017 (with respect to 9.57% in 2008). In 2017 3.3 per cent of the GDP was realized by agriculture. In 2018 the percentage of ar- able land was 46,59 per cent (48.37% in 2000) and that of agricultural land in 2018 was 57.44 per cent (62.93% in 2000). Arable and agricultural land slightly diminishes requir- ing a more intensive agriculture. A review of the most relevant publications on landscape degradation processes will not be provided below because of limited space. Sheet erosion Soil erosion is the most important land deg- radation process in agricultural areas. Ag- riculture is extended to the hilly countries in Hungary and so the risk of soil erosion is very high there. Both sheet and gully erosion are present. 2.3 million hectares are affect- ed by water erosion (13.2% slightly, 13.6% moderately and 8.5% severely eroded) and 1.5 million hectares by wind erosion (Ste- fanovits, P. and Várallyay, Gy. 1992). Water-erosion processes imply a consider- able risk in the mountain and hilly regions because of relief and drainage conditions. A significant area of hillslopes is used for agriculture. Sheet erosion on arable land is especially hazardous on large arable fields created mainly in the 1960s and 1970s. The main triggering factors of water erosion are soil parent material (easily erodible loose sediments), slope gradient, high intensity rainfalls and land use. In summer, after the harvest, exactly in the period when extreme rainfalls are likely to happen the surface is without vegetation cover, implying a high soil erosion risk. Soil erosion maps compiled during the last 5–6 decades present actually soil erosion sen- sitivity. The given soil loss values indicate the degree of erosion so that in reality it is a degree on a scale between slight and strong erosion which is behind the values given as soil loss, in tons per hectare. The most recent soil erosion map was pre- pared in the Institute for Soil Sciences and Agricultural Chemistry of the Hungarian Academy of Sciences by Pásztor, L. et al. (2015) (Figure 4). It can be observed on the map that there is a strong relationship be- tween relief and soil loss. Gully erosion The main triggering factors of gully erosion in Hungary are soil parent material (loose sediments), slope gradient, rainfall amount and intensity (especially extreme rainfall events), land use and vegetation cover. De- forestation followed by arable cultivation on hillslopes covered by loose sediments leads to the development of deep gullies within a short time. Soil types and land use play a less important role because they are not in- dependent from relief. The physical and chemical properties of loess and loess-like sediments promote pipe development. Pipes contribute to gully de- velopment, to deepening of the gullies. The map of gully distribution is shown in Figure 5. Digitized 1:10,000 maps provided the basis for this map. The distribution of the gullies is very high in the mountain for- ests, developed during a long period of time, whilst the gullies and rills on arable land were labelled before each cultivation operation. Ephemeral gullies are difficult to survey. The high gully density values in the forests reflect intensive soil erosion of former times and this doesn’t mean a high erosion risk today. The major part of the data falls into the cat- egories < 2.5 m per km2. The highest category of > 25 m per km2 represents 0.7 per cent of the data. Note that two thirds of the territory of Hungary are lowlands where gully den- sity was not surveyed and so this relatively small value is quite remarkable. 211Kertész, Á. and Křeček, J. Hungarian Geographical Bulletin 68 (2019) (3) 201–221. Fig. 4. Soil erosion risk map of Hungary. Source: Pásztor, L. et al. (2015). The legend categories (1–9) correspond to the following tons per ha per year values: 1 = 0.0–0.5; 2 = 0.5–1.0; 3 = 1.0–1.5; 4 = 1.5–2.0; 5 = 2.0–5.0; 6 = 5.0–8.0; 7 = 8.0–11.0; 8 = 11.0–100.0; 9 = > 100.0 Fig. 5. Gully dissection map of Hungary (km per km2) after Jakab, G. 2012. Source: Kertész, Á. et al. (2012). Kertész, Á. and Křeček, J. Hungarian Geographical Bulletin 68 (2019) (3) 201–221.212 Wind erosion Wind erosion affects 16 per cent of the coun- try area. High wind erosion risk endangers 10 per cent of the surface. 20 per cent of the country area is covered by windblown sand. Sandy soils are obviously prone to wind ero- sion. In addition to soil parent material the main controlling factors are geomorphol- ogy, climate, soil moisture, vegetation, land use and farming practices (Farsang, A. et al. 2017). Seasonal changes of wind erosion activ- ity are related to soil moisture conditions and to vegetation cover. Wind erosion risk will in- crease with global change, first of all due to the growing frequency of drought periods. A detailed analysis on wind erosion in Hun- gary including wind erosion maps is provid- ed in this issue by Négyesi, G. et al. (2019). Soil sealing The percentage of sealed areas in Hungary in 2012 was 3.21 per cent in 2009 only 3.17 point- ing to an increase of almost 10 per cent in four years (EEA, 2017). Figure 6 shows the degree of soil sealing in Hungary. The map was com- piled from COPERNICUS data of 2015. In 2015 the total sealed area covered al- ready 3.98 per cent of the country area. The area of sealed surfaces between 30–60 per cent is 2.1 per cent of the country area and 52.8 per cent of all sealed areas. If we compare the percentage of sealed ar- eas in Hungary with that of other European countries we come to the conclusion that the value is not very high, it is still acceptable. The reason for this is the high proportion of agricultural, forested and semi-natural ar- eas (e.g. wetlands), like in the cases of France (2.84%) and Denmark (3.62%). Salinization, secondary salinization Concerning extreme soil reaction, both ex- tremes, i.e. acidification and salinization oc- cur in Hungary. Acidification is related to non-calcareous parent material, to leaching and to plant residues decomposition as well as to air pollution and to improper fertilizer application (especially N fertilizers). The lat- ter is more important (Várallyay, Gy. 1989) than dry and wet acid deposition. Salinization is a widespread process in the lowland areas of Hungary. It is important to note that salinization is a natural soil for- mation process. Today saline areas belong to those of nature protection because they represent a special, unique value and they have to be protected. Scientific publications on salinization start- ed at the end of the 19th century. The exten- sion of saline areas is one of the largest in Europe, i.e. 560,000 ha occupying 6 per cent of the country area (Tóth, G. et al. 2008). They develop on the Great Hungarian Plain in the areas with shallow salty ground water table (Figure 7). The development of the areas of second- ary salinization is related to human activi- ties. Previously good quality soils become saline because of rising groundwater levels as a result of improper irrigation and inap- propriately planned irrigation systems. The estimated area of secondary salinization in Hungary is 400,000 ha (KSH, 1986). Saline areas are present in 67 natural mi- cro-regions of the country. The largest saline areas are in the following micro-regions: Hortobágy (939 km2), Tiszafüred–Kunhegyes Plain (359 km2), Csongrád Plain (296 km2), Szolnok–Túr Plain (277 km2), Bihar Plain (273 km2) and Dévaványa Plain (268 km2) (Madarász, B. 2019). The areas sensitive to secondary sa- linization were determined from water depth data, critical water depth and the saline areas of the agro-topographical map (Figure 8) (Madarász, B. 2019). On the basis of the results it can be asserted that 1 m rise of groundwater depth would only affect a smaller area (34,000 ha), but in the case of a 1.5 m rise the size of the areas affected by secondary salinization would be greater than 145,000 ha and the result of a rise of 2 m it would be 235,700 ha. 213Kertész, Á. and Křeček, J. Hungarian Geographical Bulletin 68 (2019) (3) 201–221. Fig. 6. Soil sealing map of Hungary. (Degree of soil sealing in percentage.) Fig. 7. Saline soils of Hungary. Source: RISSAC (1991) Kertész, Á. and Křeček, J. Hungarian Geographical Bulletin 68 (2019) (3) 201–221.214 Those areas are the most susceptible and most endangered where the process of sa- linization can start due to a small water level rise of less than one metre. These territories are attached to existing saline areas along the Tisza, Maros and Körös rivers. The susceptibility map can be successfully used in decision making and planning pre- ceding new investments and the application of new technologies if they may affect the groundwater level. Physical degradation Human activities, e.g. the application of heavy machinery on intensively cultivated fields are the main triggering factors of physical degradation processes. They include compaction, structure destruction and sur- face sealing. A classification system of Várallyay, Gy. and Leszták, M. (1990) was elaborated for Hungarian soils from the aspect of their sus- ceptibility to physical degradation: 1. Non-susceptible soils: sandy soils with- out structure and with a low content of ce- menting compounds (such as carbonates or sesquioxides); 2. Slightly susceptible soils: medium-tex- tured soils with well-developed structure and high aggregate stability; 3. Moderately susceptible soils: medium- textured soils with moderately developed structure and low aggregate stability; 4. Soils susceptible to compaction and sur- face crusting but not to structural damage: sandy soils without structure but with a high content of cementing compounds, mainly carbonates; 5. Soils susceptible to structural damage and compaction: heavy-textured soils of swelling-shrinkage character and low struc- tural stability; 6. Soils susceptible to both structural dam- age and compaction due to salinity-alkalinity; Fig. 8. Extent of areas susceptible to secondary salinization as a function of potential rise of water level. Source: Madarász, B. (2019). 215Kertész, Á. and Křeček, J. Hungarian Geographical Bulletin 68 (2019) (3) 201–221. 7. Organic soils (peats); 8. Shallow soils (solid rock or cemented layer near the surface). According to Birkás, M. et al. (2000) soil compaction is estimated to be present on nearly 50 per cent of Hungarian cropland. More than 50 per cent of Hungarian soils are subject to physical degradation to some extent. However, their exact extension is not known. According to previous surveys (Farsang, A. 2011) 13 per cent of Hungarian soils are strongly, 18 per cent moderately and 23 per cent slightly susceptible to physical degradation. The susceptibility map (Figure 9) was pre- pared by Madarász, B. (2019), based on the reclassification of soils by texture classes (1 = clay, clayey loam, loam; 2 = sandy loam; 3 = sand, peat, coarse fragments), organic ma- terial stock (1 = < 100 t/ha; 2 = 100–300 t/ha; 3 = > 300 t/ha). Three CORINE categories were created allowing for weighting soil characteristics data (0 = artificial surfaces, e.g. settlements, areas covered with water; 1 = arable land; 2 = forested areas). The three categories of susceptibility are equally distributed (29%–31%–33%). It is quite probable that global climate change will not seriously effect physical soil degra- dation. However, if the extent of the areas covered with inland water will increase, it will influence the distribution and extent of the areas susceptible to physical degradation as well. Landslides Landslides are widespread in Hungary be- cause of the wide availability of unconsoli- dated sediments. They occur on hillslopes, piedmonts, mountains and basins. Mass movement hazard is very significant in the regions where landslides frequently happen. Fig. 9. Areas susceptible to physical degradation. – white = settlements, areas covered by water; red = highly susceptible; yellow = susceptible; green = less susceptible areas. Source: Madarász, B. (2019). Kertész, Á. and Křeček, J. Hungarian Geographical Bulletin 68 (2019) (3) 201–221.216 Most landslides develop on Oligo-Mio-Pli- ocene clays, sands and marls, with Pleisto- cene paleosols of high clay content covered by loess mantles of different thickness. Other important controlling factors of landslide formation are the structure, espe- cially the alternation of permeable and im- permeable strata, high relative relief values and a relatively humid climate. Precipitation, especially winter precipitation plays an im- portant role in landslide development. The location can also be a triggering factor of landslides. They are quite widespread in the valleys of the rivers on riverbanks (e.g. along the Danube, Hernád and Sajó rivers) and along the lake shores of the biggest lakes, i.e. Balaton and Fertő. The most frequent types are rotational slumps, sliced landslides and layered slides. Human-induced mass movements are typi- cal of spoil heaps in mining districts (Józsa, E. et al. 2019). A detailed analysis of landslide hazard in Hungary is published in this issue by Józsa, E. et al. (2019). Desertification sensitivity Europe including Hungary is also threatened by desertification. Aridification is already present in the central part of Hungary, i.e. in the Danube-Tisza Interfluve. Aridification is understood meaning increasing dryness (aridity) of the climate as a result of global climate change and its environmental con- sequences. Based on 358 MODIS 8-day com- posite images drought frequency increased between 2000 and 2014 (Gulácsi, A. and Kovács, F. 2018). Shorter or longer dry periods in the past have led to serious water deficit and water imbalances affecting natural systems and land resource production systems. The main driv- ing force is the depletion of the groundwa- ter reserves because of less precipitation and high evaporation, the extraction of confined groundwater for drinking water supply, affor- estation and other land use changes, drainage regulation, direct groundwater extraction and reduced recharge from the mountains, hills and from the Danube. Desertification risk will grow with climate change. Climate change in Hungary is primarily characterized by increasing drought sensi- tivity (Farkas, J.Zs. et al. 2017). The identi- fication of the areas sensitive to desertifica- tion is an important task also for the prepa- ration of decision making. The ESAI index (Environmentally Sensitive Area Index) ap- plied and validated in Mediterranean Europe (Kosmas, C. 1999; Brandt, J. 2005) is the basis of the method to determine desertification sensitivity in the Danube-Tisza Interfluve. The study area is almost 10,000 km2 includ- ing the administrative area of 104 municipali- ties. Four factors are included in the sensitivi- ty analysis (Figure 10): 1. soil (soil texture, soil water management, SOM content, salinity); Fig. 10. Soil (1), climate (2), vegetation (3) and land management (4) sensitivity from the aspect of desertification in the Danube-Tisza Interfluve by Örsi, A. Source: Kertész, Á. et al. (2015). 217Kertész, Á. and Křeček, J. Hungarian Geographical Bulletin 68 (2019) (3) 201–221. 2. climate (mean annual rainfall [1961–1990], drought index [1961–1990] – Pálfai, I. et al. 1999); 3. vegetation (percentage of forests, fire risk); 4. land use intensity (Kertész, Á. and Örsi, A. 2013; Kertész, Á. et al. 2015). The sensitivity of the vegetation was calcu- lated on the basis of fire risk. The intensity of land use was determined by the total amount of water use per unit area. Sensitivity to desertification is presented in Figure 11. The north-western and south-east- ern parts of the area are the most sensitive to desertification. Figure 11 consists of two maps. Map 1 was prepared by taking only soil, climate and vegetation sensitivity into account. Land use intensity is involved in the analysis on Map 2. According to climate change scenarios desertification risk will grow. Temperature increase and precipitation decrease accompa- nied with more frequent and longer periods of drought call for a policy making strategy to combat desertification. Landscape aesthetics This subchapter is not about a landscape degradation process. The aesthetical value of the landscape expresses the situation of the landscapes of Hungary today. Hungary is a relatively green country with a lot of natural landscape elements and landscapes. The current state of the landscape aesthetical value of Hungary was determined by GIS methods. Landscape el- ements increasing landscape beauty (relief, forest cover, lakes and rivers, protected areas and vineyards) were evaluated first. The second step was the evaluation of artificial landscape elements. The classifica- tion and evaluation of artificial landscape elements were carried out according to their range and their negative or positive effect on the surrounding landscape. The landscape aesthetical map of Hungary evaluating both natural and artificial land- scape elements is presented in Figure 12. According to Figure 12 the general statement is that the aesthetical value of Hungarian landscapes is high. The map helps to identify the Hungarian landscapes with outstanding beauty and rich biodiver- sity. The above maps are useful and easily understandable products for the experts of tourism. The complex evaluation of natural and artificial landscape elements is a valu- able supporting tool for decision making. Conclusions The above review of landscape degrada- tion processes in the world and in Hungary is part of the research activity carried out within the framework of an OTKA project (see acknowledgement below). Comparing the processes of landscape degradation in the world and in Hungary the main conclusion is that the landscapes of Hungary are relatively well maintained and they are part of the most valuable landscapes in Europe. This statement doesn’t mean that the above described processes should not be taken seriously. All degradation processes represent important environmental problems which have to be further investigated, ana- lysed and on the basis of these the elabora- tion of a well-established policy making is necessary. Fig. 11. Desertification sensitivity indices in the Danube-Tisza Interfluve (1) due to natural factors and (2) taking land use intensity into account by Örsi, A. Source: Kertész, Á. et al. (2015). Kertész, Á. and Křeček, J. 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