<4D6963726F736F667420576F7264202D20CF2EDAC8CF20C7E1CEC7E1DE20D5C7E1CD> Diyala Agricultural Sciences Journal, 3( 2 ) 24 – 35 , 2011 Mahdi 24   ECOLOGICAL STUDY OF NICHE DIFFERENTIATION IN TEN PLANT SPECIES. Abdulkhaliq S. Mahdi * Horticulture Department - College of Agriculture - University of Diyala. ABSTRACT Investigation of niche differentiation of ten wild plant species have been showed a little sign of separation between ten species of nine soil characteristics axes. The separation only by random samples (vegetation vacancy) from the target species, in case of EC and Ca++. But in term of pH and K+ there was only 10% separation between target species. Concluding that niche differentiation between target species is not sufficient to interpret plants coexisting, might be because all plants need the same requirements of water, light, carbon dioxide, and nutrition elements. INTRODUCTION Niche is the unique way of ecological factors to which an organism is best adapted (Ackerly, 2004; Voorde et al., 2011). All of the environmental conditions are necessary for an organism to maintain available population, and the amount of each resource required to do so. The ecological niche is therefore a characteristic of an organism, or by extension a characteristic species (Gross et al. 2007; Law et al., 2009). The apparent successes of niche differentiation in explaining coexisting in animals communities, can be explained in part by their mobility, but more important by the diversity of food available to them (Begon et al., 1990; Schneider and Illian 2006). Plant ecologist have had a long-standing interest in the conditions under which species coexist with communities. Many aspect of plant coexisting remain unresolved (Mahdi, 1988 ; Mahdi et al., 1989; Mommor et al., 2010). Several axes has been used in this study to determine the niche of ten target species, precluded statistical analysis, whether the amount of niche separation is compatible ـــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــ Received for publication July 17 , 2011 . Accepted for publication August 7 , 2011 . Diyala Agricultural Sciences Journal, 3( 2 ) 24 – 35 , 2011 Mahdi 25   with observed number of species (Auebrach and Shimida 1993; Coomes et al., 2002). MATERIALS AND METHODS Site and Species: The site understudy was semi-natural community, located between Agriculture College, and Education Sport College, University of Diyala, which about 20 x 50m. The study was carried out in spring / March 2010. Six soil samples were obtained from beneath of each the ten target species. The soil sample was immediately adjacent to the root of the target species. The plants (target species) were chosen because they were relatively abundant and common species plants in the area. The species are: Anagallis arvensis (Aa), Atriplex campanulate (Ac), Cardaria draba (Cdr), Cynodon dactylon (Cd), Lactuca serriola (Ls), Malva paryuflora (Mp), Imperata cylindrical (Ic), phalaris minor (Pm), Salsola kali (Sk), Silybum marianum (Sm), as well as random samples (r), were taken from vacancy between individual plants. The procedure for taking samples soil was as follows: The cylindrical core had a cutting edge and was of 3.5 cm diameter (11 cm2 area) with 15 cm depth. Soil analysis Each of the soil sample was spread out in the laboratory to be dried, and then sieved. Part of the soil was used to measure pH values by pH meter, and EC by Electrical Conductivity set, then the same sample was used to measure saturation percentage (SP%) and field capacity (FC%). The other part of soil sample was used for the determination of Na+, Ca++, K+ , Cl- and Mg++ , by atomic absorption as described by Allen et al. (1974) ; Moor and Chapman (1986). RESULTS AND DISCUSSION AS in Fig. 1, the soil characteristics showed the following values: For EC Silybum marianum and random samples fall at two endings average (0.92 – 7.76) ds.m-1. Whereas pH (7.72 – 8.45), in contras situation random samples first and S. marianum in the end. In most of characteristics, K+ , EC, Na+ , Mg++ , and Ca++ random samples placed in the end of maximum values. Whereas in case of FC, Cl- and SP (Saturation percentage) characteristics the position of random samples is about in the middle values. Diyala Agricultural Sciences Journal, 3( 2 ) 24 – 35 , 2011 Mahdi 26   Diyala Agricultural Sciences Journal, 3( 2 ) 24 – 35 , 2011 Mahdi 27   Fig. 1. Mean of pH values, SP% (Saturation percentage), FC (Field Capacity), Cl- ppm, K+ ppm, EC (Elecrical conductivity) ds.m-1, Na+ ppm, Mg++ ppm and Ca++ ppm of ten species & random sample. The symbols of species are refer to scientific names. One way analysis of variance shows that only EC and pH values were significant at p<0.001. Whereas K+ and Ca++ values were significant at p<0.05 (Table 1). Diyala Agricultural Sciences Journal, 3( 2 ) 24 – 35 , 2011 Mahdi 28   Table 1. One-way analysis of variance. Variables F values Saturation percentage (SP %) Field Capacity (FC %) Electrical Conductivity (EC ds.m-1) pH Na+ (ppm) K+ (ppm) Mg++ (ppm) Ca++ (ppm) Cl- (ppm) 1.44 ns 0.76 ns 4.21 *** 3.24 *** 1.57 ns 2.22* 1.80 ns 2.30* 0.54 ns ns refer to non-significance. * represent to p<0.05. *** represent p<0.001 Total d.f. = 65. GT2 multiple comparison test (Sokal & Rolf 1981) separated only random samples from other species in EC (Table 2), and Ca++ (Table 3). In pH values, the separation of Phalaris minor, Cardaria draba, Malva parviflora, Anagallis arvensis and Silybum marianum from random samples and Cynodon dactylon, then Imperata cylindrical from S. marianum (Table 4). In term of K+ separation were Malva parviflora from Anagallis arvensis, Phalaris minor, Cynodon dactylon, Salsola kali and Lactuca serriola, separation of random samples from Anagallis arvensis and Phalaris minor. finely separation Imperata cylinderica from Anagallis arvensis (Table 5). Diyala Agricultural Sciences Journal, 3( 2 ) 24 – 35 , 2011 Mahdi 29   Table 2. GT2 Multiple comparison of EC (Electrical Conductivity) ds.m-1. Species Sm Mp Cd Aa Pm Ls Sk Ae Cdr Ic r S. marianum M.parviflora 0.29 C.dactylon 0.43 0.14 A.arvensis 0.68 0.39 0.25 P.minor 0.69 0.40 0.01 0.01 L.serriola 0.80 0.51 0.36 0.12 0.11 S.kali 2.14 1.85 1.71 1.47 1.46 1.35 A.campanulat 2.61 2.32 2.18 1.93 1.92 1.81 0.47 C.draba 2.84 2.55 2.41 2.16 2.16 2.05 0.70 0.23 I.cylindrica 3.94 3.65 3.51 3.26 3.25 3.14 1.80 1.33 1.10 R. samples 6.84* 6.55* 6.41* 6.16* 6.16* 6.05* 4.70* 4.23* 4.00 2.90 mse = 8.92 (mean square error from analysis of variance). MSD = (minimum significant difference). = mx(k & v). (S2)1/2 Where m = 3.5 (from Sokal & Rolf (1981), Table 21. x is the probability = 0.05, k is d.f = 11 - 1 = 10, S2 = mse/n = 8.92/6 = 1.487 MSD = 3.4 x (1.487)1/2 = 3.4 x 1.22 = 4.15 All the values in the Table, bigger than (4.15) are significant different at p=0.05 level. Table of Xi – Xj (in rank order of increasing means). Diyala Agricultural Sciences Journal, 3( 2 ) 24 – 35 , 2011 Mahdi 30   Table 3. GT2 Multiple comparison test of Ca++ ppm. Species Sm Mp Cd Aa Pm Ls Sk Ae Cdr Ic r S.marianum A.arvensis 71 C.dactylon 342 271 L.serriola 520 520 178 M.parviflora 542 471 200 22 P.minor 750 679 408 230 208 S.kali 1006 935 664 486 464 256 C.draba 1025 954 683 505 483 275 19 A.campan. 1834 1763 1492 1314 1292 1084 828 809 I.cylindrica 2176 2105 1834 1656 1534 1426 1170 1151 342 R.samples 5133* 5062* 4791* 4613* 4591* 4383* 4127* 4108* 3299* 2957* Mse = 4283165, S2 = 4283165/6 = 713860.83 MSD = 3.4 X (713860.83)1/2 = 3.4 X 844.9 = 2873 Table of Xi − Xj (in rank order of increasing means). Diyala Agricultural Sciences Journal, 3( 2 ) 24 – 35 , 2011 Mahdi 31   Table 4. GT2. Multiple comparison test of pH. Species r Cd Ic Ls Ac Sk Pm Cdr Mp Aa Sm R. samples C.dactylon 0.05 I.cylindrica 0.30 0.25 L.serriola 0.34 0.29 0.04 A.campan. 0.35 0.29 0.04 0.01 S.Kali 0.40 0.34 0.10 0.06 0.05 P.minor 0.51* 0.46* 0.21 0.17 0.17 012 C.draba 0.50* 0.46* 0.21 0.18 0.17 0.12 0.01 M.parviflor 0.54* 0.49* 0.24 0.20 0.19 0.14 0.03 0.03 A.arvensis 0.54* 0.49* 0.24 0.20 0.20 0.14 0.03 0.03 0.01 S.marianum 0.73* 0.68* 0.43* 0.39 0.38 0.33 0.22 0.19 0.19 0.19 Mse = 0.0864, S2 = 0.0864/6 = 0.0144 MSD = 3.2 x (0.0144)1/2 = 3.4 x 0.12 = 041 Table of Xj - Xj (in order of increasing means). Diyala Agricultural Sciences Journal, 3( 2 ) 24 – 35 , 2011 Mahdi 32   Table 5. GT2 Multiple comparison test of K+ ppm. Species Aa Pm Cd Sk Ls Ac Cdr Sm r Mp A.arvensis P.minor 12.5 C.dactylon 55.3 42.8 S.kali 59.8 47.3 4.5 L.Serriola 60.2 47.7 4.9 0.4 A.campan. 74.2 61.7 18.9 14.4 14.0 C.draba 86.5 74.0 31.2 26.7 26.3 12.3 S.marianum 88.3 75.8 33.0 28.5 28.1 14.1 1.8 I.cylindrica 98.7* 86.2* 43.4 38.9 38.5 24.1 12.2 10.4 R.samples 117.0* 104.5* 61.7 57.2 56.8 42.8 30.5 28.7 18.3 M.parviflo. 164.5* 152.0* 109.2* 104.7* 90.3 78.0 76.2 65.8 65.8 74.5 Mse = 4973, S2 = 4973/6 = 828.83 MSD = 3.4 x (828.83)1/2 = 3.4 x 28.79 = 97.88 The average of soil characteristics (Fig. 1) showed moderate value of saturation percentage (SP %), field capacity (FC %), Ca++, and Mg++ . The pH values tend to be alkaline, this is the attribute to nature of semi-desert soil regions (Grime 1990; Bolker et al. 2003). Whereas relatively high values of Cl- , Na+ , & EC, but K+ was very low values. The effect of vegetation seems to be increased (Mahdi et al. 1990; Law and Dieckmann 2000) comparing with random samples. In case of K+ , Na+, and Mg++ the effect was in decreased comparing with random samples, because the consumption of nutrition elements. In term of EC, the vegetation decreased Diyala Agricultural Sciences Journal, 3( 2 ) 24 – 35 , 2011 Mahdi 33   evaporation from the soil, thus the salinity on its surface was decreased (Yodzis 1986; Murrell and Law 2003). One-way analysis of variance among species confirms that there is a lack at separation of SP%, FC%, Na+ , Mg++, and Cl- . In terms of K+ and pH there were little niche separation, being only 13% (Excluded random Samples). The results show that there is little niche separation between species. In view of the major concept of niche theory that two (or more) competing species cannot coexist in the same niche (Hardin 1960). This study may be regard the theory is inappropriate to applied on the plant species (Mahdi et al. 1989; Voorde et al. 2011). 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Bezemer. 2011. Intra and interspecific plant-soil interactions, soil legacies and priority. Journal of Ecology, 99, 945-953. Yodzis, P. 1986. Competition mortality, and community structure, Community Ecology, pp. 480-491. Harper & Row, New York, USA. . دراسة بيئية عن تمايز ألمركز ألبيئي في عشرة أنواع نباتية الخالق صالح مهدي عبد .جامعة ديالى -آلية ألزراعة -وهندسة الحدائق لبستنةاقسم لخالصةا دراسة التمايز ألبيئي لعشرة أنواع نباتية برية، أظهرت قليل من الفصل فيما بينها لتسعة صفات تربة ) والتي أخذت من ألفراغات بين ألنباتات تحت ألدراسة(ألفصل كان فقط للعينات العشوائية . تنموا عليها تاسيوم، ولباروجيني و عنصر حالة ألرقم ألهيدلكن في . و عنصر ألكالسيوملصفتي ألتوصيل ألكهربائي أما بقية صفات ألتربة أألخرى فلم تظهر إي . هناك فقط عشرة بالمائة فصل بين النباتات تحت ألدراسة تحت كافياً لتفسير ألتعايش بين للنباتاتليس ألبيئي بين ألنباتات نستنتج إن تمايز ألمركز .فصل فيما بينها ت لها نفس أالحتياجات من ألماء و ألضوء وثاني أوكسيد ألكربونإن ألنباتاوهذا يعود لسبب .لدراسةا .والمغذيات المعدنية