The Chorotypes And Zoogeographical Division Of Amphibian And Reptile In Xinjiang And Adjacent Areas

We try to determine the zoogeographic division of amphibian and reptile in Xinjiang and the adjacent regions based on the clustering methodology of species level, genus level and strong and weak boundary test. According to the analysis, we divided the research area into 17 provinces,6 subregion,5 region and 2 subrealm. Compare with anterior research,we determined the boundary between the two subrealms that runs along the Altai Mountains, the Sayan Mountains, the Hangai Mountains and the Mongolian Dagurr Mountains. The OGUs south of this line belong to the Central Asia Subrealm, and those OGUs to its north belong to the Euro-Siberian Subrealm. Quantitative analysis confirms that the widespread existence of transitional zones,which is a salient characteristic of the arid areas within Centra l Asia,results in indistinct boundaries and exsistence of consults for long time. It has been proposed that the Tianshan Mountains should be set to a separate Middle Asian mountain region, which would be at the same level as the Mongolia-Xinjiang region. It has also been supposed to add a new zoogeographical unit “ Turan Region”. We considered the boundary between Mongolia-Xinjiang region and Qinghai–Tibet region runs through the Qaidam Basin, the Kunlun–Altun Mountain and the Pamirs,so the area south of this line belong to the Qinghai-Tibet region,and those to its north belong to the Mongolia-Xinjiang region. Based on the analysis, we comfirmed the Ili Valley and Emin Basin should be placed under the Turan region; the Qaidam Basin, the Kunlun–Altun Mountain and the Pamirs belong to Qinghai–Tibet region; the Altai Mountain of Irtysh River upstream in Xinjiang was proposed to be classified into Euro-Siberia region rather than into Mongolia-Xinjiang region; the Barkol Hills and Karlik Mountain have tremendous difference with middle and west Tianshan Mountain, so they were classified into Dzungaria Basin subregion in Mongolia-Xinjiang region. Removing the widespread species is not recommended in the study of amphibians and reptiles geographical division of arid areas. It is not adequate to solve the high grade zoogeographic division of amphibian and reptile only by the cluster analysis of species distribution, but high-level taxonomic category clustering analysis with the test of independence applied to strong and weak boundaries resolved the distribution patterns and high level zoogeographical division s of amphibians and reptiles in our study area. This method should be applicable to research not only on other animal groups, but also on large-scale zoogeographical divisions, the barrier effects of physical geographic boundaries, and the attributions in transitional areas.Based on the distribution data of 128 species, in 75 geographical units, amphibians and reptiles within the study area are divid ed into six primary and 16 secondary chorotypes in accordance with the characteristics of the geographic distribution. We get eco-geographic R cluster based on 38 ecological factors matrices for 75 geographic units. Discriminant analysis found that the ecological factors associated with temperature and precipitations are the key factors affecting the distribution pattern of five chorotypes. The correct rate of discriminant function of ecological factors determining certain distribution pattern is not very h igh,indicating that the distribution of amphibians and reptiles within the study area are dominated by geographical factors. Therefore, amphibians and reptiles within the study area are divided into six primary and 16 secondary chorotypes in accordance with the characteristics of the geographic distribution. Advanced geographical(region-level) units correspond directly to primary distribution pattern(except widespread type). For lower zoogeographical unit, the secondary distribution pattern has explicit con gruent relationship with provinces which possess lots of endemic species. The correspondence between secondary chorotype and provincial unit with many endemic species is clearer. On a large scale, geographical factors dominate the chorotypes and zoogeographical division but in small-scale, ecological factors also have a negligible effect. Therefore, the chorotypes and zoogeographical division of amphibians and reptiles reflect temporal evolution of a nimals and modern ecological geographical distribution.