Dynamic And Function Of Soil Fauna Community During The Process Of Main Species Litter Decomposition In Leymus Chinensis Grassland

Leymus chinensis grassland in the west of JiLin Province is the eastern beginning of European-Asian grassland zone. Climate conditions are better than traditional grassland, so the production of vegetation here is bigger. These years the deterioration of grassland in this area became more and more serious, and then the function of grassland ecosystem got sick day after day. Though there were many studies on recovering this ecosystem's function and process, scientists focus their researches on the function of soil fauna during matter decomposition and nutrient release process were really rare.The thesis had been studied on main litter species mass losing and soil fauna community dynamic during the second year decomposition process in Leymus chinensis grassland. And one goal of this study is discussing the contribution of different soil fauna on litter decomposition; the other goal is discussing the relation ship between characteristics of soil fauna community and environment factors. This study cannot only give some scientific basics for the recover of Leymus chinensis grassland ecosystem, but also enrich our Chinese researches about soil fauna function in grassland ecosystem.In April, June, August and October, 2009, we got different litter bags back to the laboratory respectively and calculated mass losing percent in each litter bags. The results showed that there were differences in mass losing among litter species and mesh sizes. Among three litter species, Chloris virgata had highest decomposition percents, while Calamagrostis epigejos had lowest mass losing percents, and Leymus chinensis decomposition percents were between these two. Litter in mesh size 4㎜and 2㎜ litter bags had significant higher decomposition rates than 0.01㎜.By hand selecting and Tullgren method, the study totally gathered 10551 soil fauna individual from litter bags, belonging to 1 phyla, 2 classes, 13 orders and 36 families. Dominant groups included Gamasida, Actinedida and Oribatida. Lygaeidae, Psocidae, Cydnidae, Pseudachorutidae, Carabidae, Tubalifera, Isotomidae were common groups. Others were rare groups, for example Nitidulidae, Anthocoridae, Salticidae, Heteropodidae, Formicidae, Coccidae, Paronellidae, Carabidae.We also studied soil fauna community composition in background environment. Totally we gathered 2707macro soil fauna individuals, belonging to 1 phyla, 2 classes, 14 orders and 31 families. Formicidae was dominant group.Muscidae, Scarabaeidae larve, Staphylinidae et al. were common groups. Besides, 799 meso-micro soil fauna individuals were gathered. Those belonged to 1 phyla, 2 classes, 13 orders and 17 families. Oribatida and Gamasida were included in dominant groups. Common groups composition were Actinedida, Isotomidae, Hypogastruridae et al.Our study proved that in litter decomposition process soil fauna had accelerative effects. However there were differences among soil fauna kinds. Meso-micro soil fauna had much more contribution on the decomposition. The Pearson correlation analysis indicates there was significant negative relationship between litter mass loss percent and characteristic of soil fauna community. By ANOVA, time factor affected on soil fauna which live in litter bags significantly. Grey correlation analysis revealed that soil organic matter and soil pH are significant factors which respectively affected soil fauna individual number and group number.