中国干旱地区啮齿动物物种分布的区域分异

DISTRIBUTION OF GLIRES IN ARID REGIONS OF CHINA

搜集整理我国干旱地区啮齿动物地理分布数据 ,通过生境分析 ,确定啮齿动物分布区。基于GIS技术 ,以面积约为 6 470km2 的 76 6个栅格收集我国干旱地区啮齿动物的二元分布数据 ,采用多元分析的分层聚类方法 ,依据欧氏距离平方值 ,将地理分布单元划分为若干个组。结果表明 ,当欧氏距离平方值分别为 11 379、17 0 6 8、 2 2 75 8和 2 8 44 7时 ,76 6个地理分布单元依次可分为 30、 9、 5和 3个组。分布单元组的物种组成比较和生态型分析表明 :①在我国干旱地区的海拔较低地带 ,景观自东向西由草原、荒漠草原过渡到荒漠 ,地理分布单元组亦呈现相应的分布格局 ,喜湿的物种逐渐减少 ,耐旱的种类增加 ;②青藏高原、帕米尔高原寒漠与蒙新温性和暖温性荒漠啮齿动物物种数和组成相近 ,物种多样性低 ;③阿尔泰山地及南麓平原啮齿动物组成较为特殊 ,寒湿啮齿动物成份最高 ;④东祁连山地及其北麓以及伊犁谷地、额敏谷地、伊犁天山、准噶尔界山及东麓山前平原的啮齿动物成份较为复杂 ,物种多样性较高。我国干旱地区东部啮齿动物的物种密度和多样性高于西部 ,但在东部草原和西部荒漠之间的过渡区物种密度较高 ,表现出物种生态地理分布的边缘效应 。

The arid regions of China including Mongolian Xinjiang warm temperature arid region and Qinghai Tibet frigid arid region are located in the West of China, administerially in whole Xinjiang, nearly whole Inner Mongolia, greater parts of Tibet, Qinghai, Gansu and Ningxia, and lesser parts of Shaanxi, Shanxi, Hebei, Henan, Liaoning and Jilin, ranging from 73°40′to 123°40′E,28°to 50°N. There are 120 species of rodents including Lagomorpha and Rodentia. All of the species collection since 1950's were inspected and examined, then the distribution information including collection localities, habitat, distribution height, collection time and so on were put into database. Distributional data in literatures were also collected. Based on the revised distributional information supported by a GIS technique, MapInfo Professional Version 4 0, species ranges were predicted by a wildlife habitat model. Based on these GIS model of species range maps the distribution patterns of rodent species were studied. 766 equal area quadrangle grids that each had an area of 6 470 square kilometers were used as geographic units to collect distributional data of the species supported by MapInfo Professional Version 4 0. All the grids with the distributional data of binary attribute were divided into groups by hierarchical cluster analysis according to Euclidean distance. In order to show species richness of rodents in the groups of distributional units, we retrieved more detailed distributional information in 766 grids from GIS database. Index of Shannon Wiener in the grid groups was calculated as the index of species diversity according to the occurrence frequency of species in grid groups. Species density of distribution types, which were classified according to the species' preference to thermic and moisture, in the grid groups was also calculated. Results were showed as follows. The 766 distributional units could be divided into 30, 9, 5 and 3 groups, where Euclidean distance was 11 379, 17 068, 22 758 and 28 447, respectively. All the groups had their corresponding geographic areas in maps. Specially the species richness, species diversity, fauna and ecological distributional types in 9 groups were analyzed. From these 9 groups of distributional units, three obvious distributional regions could be recognized. They were ①ⅠAa:forest steppe and arid steppe in piedmont of Da Hinggan Mountain, east of Inner Mongolia Plateau and the area around, ⅠAb:arid steppes in Ningxia Plateau, Helan Mountain, center of Inner Monglia Plateau, Ordus Plateau and the area around, ⅠBa:Qinghai Tibet Plateau not including Qilin Mountain, and Pamir Plateau, ⅠBb:wide temperature desert from Alxa Desert to Tarim and Jungar Basin; ②ⅡA:east of Qilin Mountains, ⅡB:north slope of Qilin Mountain and its piedmont plains; ③ⅢA:Altay Mountain and the plains of south piedmont, ⅢBa:Emin Valley, boundary mountains of Jungar and its piedmont plains, ⅢBb:Tianshan Mountain in Ili and Ili Valley. Rodent species in these regions took on the distributional patterns as follows. ① In the lower altitude of arid regions of China, with the change of landscape prairie, semi desert to desert, so were the relative distribution patterns of groups of distributional units, where hygrophilous species declined and xerophilous species increased. ② Rodent components in frigid desert regions of Qinghai Tibet Plateau and Parmir Plateau were closely related to those of warm temperature and warmer temperature desert regions with lower species diversity. ③ Rodent components in Altay Mountains and the plains in their south slope were special, having more hypothermohygrophilous species. ④ There were complex rodent fauna in Tianshan mountains and the valley in Ili, boundary mountains and its eastern plains of Jungar, north slope and east of Qilian Mountain with the characteristic of intergradations. ⑤ Rodent species richness and diversity were higher in the ecotones, taking on edge effects.