干旱区生态环境知识资源中心

173 rodent species representing 70 genera and 13 families inhabit the territory of China. 4 species were recorded only on Taiwan. Basing on their geographic ranges and origin, all the continental species (except the synanthropic (3) and introduced (2) ones) were classified into 4 groups: Palaearctic (63 species), Indo-Malayan (44 species), subendemics (26 species) and endemics (31 species). The maps of the numerical distribution of each group were compiled by the means of the superposition of geographical ranges of the species. 4 foci of endemism, where the percentage of endemics and subendemics is more than 25% can be outlined: Takla-Makan desert, Tibetan Plateau, north-eastern part of China, the middle reaches of Yangtze River and adjacent areas. The highest levels of endemism were noted in Takla-Makan and Tibet, which is caused by the formation of highly specialized but not very reach in species rodent faunae. To. determine the boundary between the Palaearctic and Indo-Malayan regions, the presumed transitional zone between them was studied. That zone is outlined by the northern limit of distribution of Niviventer confucianus, which penetrates most far to the North among Indo-Malayan species, and by the southern frontier of China, since Micromys minutus, one of Palaearctic species, penetrates to the South up to northern Viet-Nam. Basing on the predominance (more than 50%) of Palaearctic and Indo-Malayan rodent species, the studied territory was attributed to one or another faunistic region. Areas, where both above mentioned groups have less than 50% of fetal species number, were classified as the transitional zone between two regions. It lies in the middle reaches of Yangtze.