干旱区生态环境知识资源中心

Geographic ranges of mammals from territory of the former USSR were matched by use of IDRISI 4.1 software for mapping mammal species richness (all mammals and, separately, quadrupeds and bats). Plains landscapes are characterized by a regular increase of mammal species richness from tundra to forest-steppe zone, where the Budyko-ratio index of aridity equals 1, then a decrease. Continental plains deserts of North Eurasia (Budyko-ratio > 3) are characterized by low species richness of mammal (thirty to thirty-three species). Mountains (with the exception of the Ural Mountains) have significantly greater mammal species richness as a result of greater diversity of habitats and smaller landscape units. Significant differences in relationships of mammal species richness in arid or mesic regions in Eurasia and North America can be explained by the influence of complicated mountain condition in North American deserts (with significantly greater habitat diversity and smaller landscape units) and by overestimation of the actual number of co-existing species as a result of superimposing mammalian ranges. This must be taken into account when attempting to correlate species richness with simple environmental descriptors, such as potential or actual evapotranspiration. Actual numbers of co-existing species from long-term studies on natural protected areas can be used to improve current knowledge regarding the relationship between spatial patterns of biodiversity and climatic change.