中文摘要：

物种多样性对生态系统功能的影响是生态学领域的核心问题之一.本研究利用内蒙古荒漠草原80 个野外植被、土壤调查样地资料,结合气候数据,探讨物种多样性、生产力与气候因子和土壤养分的关系,为进一步认识多样性-生产力关系提供参考.结果表明,1）物种多样性、生物量与年平均降水量均呈线性正相关,与年平均温度均呈线性负相关,与干燥指数均呈线性正相关.2）物种丰富度与土壤全磷含量呈线性负相关（R^2 =0.072,P〈0.05）,与速效氮含量呈线性正相关（R^2 =0.183,P〈0.01）,Shannon- Wiener指数与速效氮也呈线性正相关（R^2=0.061,P〈0.05）;生物量与土壤全氮、速效氮和有机碳含量都呈线性正相关,相关系数分别为0.150,0.177,0.089（P〈0.01）.3）群落生物量与物种多样性呈线性正相关关系.4）干燥指数是影响多样性和生物量的主要环境因子.

英文摘要：

The effect of species diversity on ecosystem function is one of the core issues in ecology.Our objec-tive was to explore the relationship between species diversity,productivity,climatic factors,and soil nutrients in the desert steppe,to enhance understanding of the diversity-productivity relationship.Species richness and Shannon-Wiener index were used to measure species diversity.Climatic,vegetation and soil data were collect-ed for 80 sampling sites across the desert steppe of Inner Mongolia.Regression analysis and stepwise regression analysis were used for determining the relationship between environmental factors and species diversity and productivity.The effects of environmental factors on species diversity and productivity were evaluated,based on the coefficient of determination from regression analysis.It was found that species diversity and biomasswere both positively and linearly correlated with mean annual precipitation and aridity index.However,Shan-non-Wiener index and biomass were both negatively and linearly correlated with mean annual temperature. Species richness was negatively and linearly correlated with soil total phosphorus content (R 2 =0.072,P <0.05),but positively and linearly correlated with soil available nitrogen content (R 2 =0.183,P <0.01);Shan-non-Wiener index was also positively and linearly correlated with soil available nitrogen content (R 2 =0.061, P <0.05),and biomass was positively and linearly correlated with total nitrogen,soil available nitrogen,and soil organic carbon content.The coefficients of determination were 0.150,0.177,0.089 (P <0.01 ),respec-tively.Biomass increased significantly with the increase of species richness and Shannon-Wiener index.These results indicate that aridity index is the most influential factor affecting species diversity and biomass of desert steppe.