Study On The Characteristics Of Soil Protozoan Community In

The community characteristics of sole protozoa in the Ahre-wetland in Danxung county of Lhasa, TAR was studed by “non-flooded Petri-dish method” and In vivo observation under microscopic for five sampling sites and 25 subsites during the period between June 2013 and May 2014. Eac h s ubs ite was devided into s urfac e layer(0-5c m)、 middle layer(5-15cm) and deep layer(15-25cm). 45 samples were examined in total. The result were follows:(1) A total of 329 protozoan species were identified. Within 121 species were Sarcomastigophora(including 15 unidentified), belonging to 16 orders, 32 families, and 51 genera. 208 species were c iliates(including 33 unidentified), belonging to15 orders, 57 families, and 83 genera. Sarcomastigophora was dominant with dominance of 36.78%. Amongst Euglenida, Volvcales and Amoebida were dominant, and each has 25, 17 and 17 spccies, with dominance of 20.66%, 14.05% and 14.05%, respectively. Arcellinida was the subdominant group, which has 15 species, with dominance of 12.40%. Both Choanogflaellida and Pelobiontida were rare among the identified Sarcomastigophora community, with dominace of 0.83%. Within the ciliates community, Prostomatida and Hypotrichida were dominant, and each has 49 and 47 species, with dominance of 23.56% and 22.60%. Peritrichida and Scuticociliatida were the secondary groups, and each has 19 and 18species, with their dominance were 12.12% and 10.10% respectively. Trichostomatida was rare among the community, with dominace of 0.48%.(2) The dominant species varied significantly with in the individual sampling s ites and seasons. There 32 dominant species in the Ahre-Wetland, and they were Oikomonas socialis, Monas sociabilis, Monas arhabdomonas, Cryptomonas ovate, Chilomonas paramaecium, Heteronema polymorphum, Platymonas sp., Distigma proteus, Anisonema reniformis, Chlamydomonas sp., Pyramimonas delicatula, Platymonas sp., Actinosphaerium eichhorni, Colpoda steini, Colpoda inflate, Nassula gracilis, Colpidium campylum, Pseudoglaucoma musorum, Uronema nigricans, Cyclidium granulosum, Halteria grandinella, Keronopsis monilata, Holosticha kessleri, Paruroleptus caudatus, Urosoma cienkowskii, Oxytricha saprobia, Opisthotricha similis, Opisthotricha euglenivora, Histriculus similis, Stylonychia mytilus and Euplotes muscicola, with the total dominace of 9.73%.(3) Using the observational datas of community characteristics, to study the soil characteris itics and the achievements gained from banning grazing.1) 48 protozoan species were unidentified, accounted for 14.59% of the total species. It illustrated that there were large number of specific protozoan in wetland soil, and the particularity of Ahre Wetland’s ecological environment.2) The number of protozoan species in spring is larger than that in summer, with the number in summer is larger than that in autumn. However, in summer the richness is the smallest, with in spring it has the largest one. The date shows that in spring the temperature rises, and ecological environment comes to be improved. In spring, all the protozoan begin to roprouce, but the individual number is small. In summer, the organisms multiply rapidly. After community succession, the dominant species arise gradually, with other species die out in varying degrees. In autumn,both the number of species and richness decrease sharply, with a drop in temperature and deterioration of environment.3) In the same season, the variation tendency between the individual sampling sites is pasture of banning grazing>residential area>open pasture. It states that the bans on grazing have an effect on the recover of species diversity.4) The species numbers reduce from the surface layer to the deep layer in the vertical distribution. The number of the surface layer species is much larger than that in the middle and deep layer, which is obvious of surface-aggregation.5) From open pasture to residential area, pasture of banning grazing, the proportion of BS groups and Simpson dominace index reduce, and Margalef richness index, Simpson divers ity index, Pielou evenness and Shannon-Weaver diversity index rise. It shows that the protozoan community of Ahre Wetland becomes more complex, with increase of species which have cleaning effect, divers ity and evenness index; decrease of dominace index.6) Comparing the protozoan of Ahre Wetland with the protozoan which have been reported,the species number of the former is much more than others. The result of Jaccard similarity analysis is extremely unsimilar(between 0.00 to 0.25). The species in Ahre Wetland are very abundant, being significantly different with protozoan in other regions of China.It reflects that the environmental conditions in Ahre Wetland are quite good.