Studies On Indiction Of Soil Fauna In Different Degraded Level Grassland Of Gemutan

The importance of the soil fauna lies in their role as soil decomposers and as a driving force in nutrient cycling ecosystem. The composition, diversity, dynamic of seasons, the distribution of temporal, spatial of soil fauna community and the enviromental factor are analyzed in the different degraded level Alpine meadow, discussed soil fauna on the environment as indicators of grassland degradation in the application of classification criterion.1. The results showed that a total of 2536 soil fauna specimens belong to 4 phyla 6 class and 17 order were collected all sampling periods and sites. And among them, 833 individual belonging to 32 groups was up to maximum in enclosuring grassland and 669 individual belonging to 25 groups in moderately degraded grassland, there was 610 individual and 28 groups in lightly degraded grassland and 424 individual and 20 groups to minimum in heavily degraded grassland.2. The composition and structure of soil fauna community were different in different seasons, there is 1121 individual soil fauna belonging to 34 groups in August and 785 individual soil fauna belonging to 28 groups in June and 626 individual soil fauna belonging to 25 groups in Octeber. The horizontal distrbution of soil fauna was not even and assembling in different degraded levels grassland. The vercital distribution of soil fauna were decreased with increase to soil depth, which show obvious nature of surface gathering in 0～10cm soil depth.3. Diversity and Eveness and Simpson index of soil fauna community were obvious difference in the different degraded levels grassland. The simility index of soil fauna is largest in lightly and moderately degraded(0.750), and that is least (0.577) in enclosuring and heavily degraded. Soil nutrient contents are significant decreased with increase to aggravation of degraded levels. Pearson correlation between the number of groups and soil pH is negative correlation and soil water contents are postive correlation. Total N and available N largerly for the number of groups of soil and the individual number of soil fauna, then others factors effect no obvious significant in soil.5. No charactersitic indicators soil fauna(IndVals>70%) has been found in all sampling sites, soil fauna meets with detector indicators(IndVals:5%～70%) in lightly degraded, in moderately degraded, in heavily degraded and in enclosring grassland 21, 18, 13 and 31 groups, respectively. there is Curculionidae, Coccinellidae and larva,Carabiladae,Hymenoptera larva,Lepidoptera,Elateridae larva and Araneae in lightly degraded. Enchytraeidae, StapHylinoidae, Locustidae, Coccinellidae and larva, Lepidoptera and larva in moderately degraded. Curculionidae larva, Aranea, Elateridae larva, Melolonthidae larva, Hymenoptera larva and Chrysomelidae larva in heavily degraded and Chrysomelidae in enclosuring grassland,which species IndVals<5% are unlikely to as a detector indicator.