沙鼠亚科物种空间分布格局及其与环境因素的关系

SPATIAL DISTRIBUTION PATTERNS OF CHINESE GERBILS (GERBILLINE) IN RELATION TO ENVIRONMENTAL FACTORS

通过查阅大量文献和标本采集记录 ,获得我国 7种沙鼠的分布资料。借助中国资源环境数据库( 1∶4 0 0 0 0 0 0 ) ,运用GIS软件 ,通过沙鼠亚科的生境分析 ,确认该类群的物种分布数据。在分布资料基础上 ,绘制物种数字化空间分布图 ,获得较为准确的物种地理分布信息。按 12 3 92 4km2 的等面积栅格收集物种分布和相关的地理要素数据 ,然后进行因子分析 ,确定影响动物空间分布的主要因素。结果表明 ,我国沙鼠亚科物种分布在 3 4 4～ 5 0 2°N ,74 1～ 12 4 1°E ,多分布在海拔 10 0 0～ 15 0 0m的荒漠和荒漠草原地带。分布区西部的物种丰富度相对高于东部。自阿拉山口 ,沿天山北麓至将军戈壁一带 ,以及河西走廊西段和弱水流域的荒漠区为物种丰富度高值区。因子分析表明 ,影响沙鼠亚科空间分布的决定因素是以土壤、植被、地貌和高度差为主的要素所构成的基本景观因子 ,其次是体现年总辐射量、年均降雨量和沙漠化程度的干旱和沙漠化程度因子 ,以及温度因子。变量分析表明 ,沙鼠亚科的物种丰富度与年均温度和沙漠化程度有着直接的联系 ;栅格因子得分分析表明 ,在沙鼠亚科物种丰富度高值区 ,干旱和沙漠化程度较高 ,年均温度较高 ,生境相对复杂。

There are seven species of Gerbils belonging to three genera mainly in the arid regions of Mongolian Xinjiang Plateau and its adjacent arid regions. Their distributional ranges include Xinjiang, Gansu, Ningxia, Qinghai, Inner Mongolia, Shannxi, Shanxi, Hebei, Jilin, Liaoning and Henan. They are important biodiversity indicator in the arid ecosystems. An approach of geographical information systems (GIS) along with multivariate analysis was applied to study the spatial distribution patterns of the gerbil species and their correlation with environmental variables using resources and environment data of China on a scale of 1∶4 000 000. Geographic distribution data were collected from literatures and museum collections. All the available geographic distribution data were used in habitat analysis with MapInfo Professional Version 4 0, and then used to get digital species range maps. Environmental variables in the distribution area of gerbils collected with the 12 392 4 km 2 equal area grids were used for factor analysis to determine the principal factors that affected the distribution patterns of gerbils. We found that distribution of gerbils ranged from 34 4°to 50 2°N and from 74 1°to 124 1°E, with altitudes from -100 to 2 500 m. The gerbils mainly inhabited desert and semi desert with altitudes from 1 000 to 1 500 m. There were more species in west than in east part of the distribution area, where the richest species of gerbils were along north piedmont of Tianshan from the Alataw Shankou to Jiangjun Gobi, and in western Hexi Hallway and Ruo Shui Valley as well. The factor analysis on the environmental variables which affect the distribution of gerbil revealed that diversity of soil, vegetation and geomorphologic and altitude difference played a dominant role as a basic landscape factor, that total annual solar radiant energy and mean annual rainfall consisted of another principal factor, a factor of aridity and desertlization tendencies, and that the third was temperature. The figure of R analysis on the loadings of environmental variables performed by the three principal factors indicated that species number of gerbils in grids was close related to mean annual temperature and desertlization tendencies. The analysis of the scores in the gerbils' distribution grids revealed that higher the species richness, higher the probability of aridity and desertlization, higher temperature and more complex the habitats were.