SPATIAL DISTRIBUTION PATTERNS OF CHINESE GERBILS (GERBILLINE) IN RELATION TO ENVIRONMENTAL FACTORS
ZHOU Li Zhi ①② MA Yong ① LI Di Qiang ③ (①Institute of Zoology, The Chinese Academy of Sciences, Beijing 100080, China) (②Biology Department, Huaibei Coal Industry Teachers' College, Huaibei, Anhui 235000, China) (③Institute
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.