中文摘要：

物种丰富度的地理格局是宏观生态学和生物地理学的中心议题之一。本文基于内蒙古草原192个野外样地的调查数据,结合各样地年平均气温、年降水量等9个气候因子,探讨内蒙古草原物种丰富度格局及其主导因素,以确定气候假说在该区的适用性。结果表明：（1）内蒙古草原物种丰富度经度格局显著,呈现沿经度升高而增加的趋势,同时由于经纬度的共线性,也呈现出沿纬度升高而增加的趋势。（2）方差分解显示,能量单独解释率为2.7%,水分单独解释率为11.4%,水分和能量共同解释率为46.3%,未解释部分为39.6%,可见能量与水分的共同作用在物种丰富度格局形成中占主导地位,支持水热动态假说。这说明水热动态假说适用于解释内蒙古草原物种丰富度格局。

英文摘要：

Understanding spatial pattern of species diversity is central to macroecology and biogeography. Based on species diversity and nine different climatic factors of 192 field sites, we explored geographic patterns of species richness and dominant factors in Inner Mongolia grassland, and further determined applicability of different climatic hypotheses in this area. Results indicated the species richness of the Inner Mongolia grassland exhibited significant longitudinal gradients, which increased from west to east. Meanwhile, because of the collinearity of latitude and longitude within the Inner Mongolia grassland, it also exhibited significant latitudinal gradients. Analysis of variance indicated that only 2.7% and 11.4% of the total variance were explained by energy and moisture factors, respectively, while 46.3% was simultaneously explained by the two groups of factors, 39.6% was explained by other undetermined factors. These results indicate that energy and moisture play a decisive role in the distribution patterns of species richness and support the water–energy dynamic hypothesis. We find the water–energy dynamic hypothesis is best suited for the Inner Mongolia grassland.