Abstract: From 1992-1995,We studied the community dynamic of macrofauna under the experimental grazing pressures in lnner Mongolia typical steppe.The relationships between the experimental grazing pressures and the density,biomass,biodiversity,evenness of macrofauna community was negative.With the grazing pressures rising,the changes of macrofauna community are not linearity.As the grazing pressures were 4 and 8 sheeps per hectare,the diversity and evenncss of macrofauna community were highcr than that of other grazing pressures.At the grazing pressure of 20 sheeps per hectare,the biomass and density of macrofauna were not very lower .but the dominant groups were simplified,and the stability of the macrofauna community is lower.Under the condition of grazing pressures increasing,the biodiversity,evenness and richness of macrofauna community were decrcasc.This largely expressed the featurcs of the soil animal response to the changes of grazing pressures.

Key words: Grassland ecosystem, Dynamic of macrofauna community, Experimental grazing pressures, Blodiversity

摘要： 本文研究在定量化实验牧压下内蒙古典型草原区大型土壤动物群落动态及其对牧压变化的反应。结果表明,在4-8只羊/hm²放牧强度下土壤动物多样性、均匀性相对较其他放牧区高。在过牧区(20只羊/hm²),土壤动物生物量、密度虽无明显降低,但优势类群单一化,群落稳定性差。土壤动物密度、生物量、群落多样性、均匀性、种类丰富度与放牧强度的提高呈负相关,但随着放牧强度的提高,上述变化不呈线性下降。放牧强度增加时土壤动物群落演替的趋势是：多样性、均匀性、种类丰富度降低,优势类群单调但生物量、密度不明显随之降低,体现了土壤动物对放牧扰动反应的特殊性。

关键词: 草原生态系统, 土壤动物群落动态, 放牧强度, 生物多样性