Based on population surveys of great gerbil(Rhombomys opimus)by blocking up the mouseholes and inspecting the opened ones conducted in three different habitats in Tengenor,Damaolianheqi,Baotou City of Inner Mongolia in February,April,June,August,October and December from 2003 to 2005,relationship between density of the great gerbil and rainfall was analyzed.Results showed that population densities of the great gerbil vary with seasons and years,and its density curves have a single peak value every year.A regression equation Y8=-8.7202 + 0.8806X(df=16,r=0.5394>r0.05=0.468)resulted from analyzing the relationship of the density to the rainfall the previous month indicates that the population size of the great gerbil was positively related to the previous month’s rainfall.The density occurring in August and October can be predicted by that in April.The forecasting models for the density in August and October are Y8=-1.0925+2.6133X4(df=6,r=0.9776>r0.01=0.834)and Y10=-0.2097+2.4992X4(df=6,r=0.9672>r0.01=0.834)respectively.
We collected available chorological data of birds and mammals in China and assigned faunal types.The 19 sub-regions of the zoogeographical regions of China were used as operative geographical units.Matrices of the geo-graphical units using the species number of each faunal type were then constructed.Based on the matrices we clustered the geographical units using a hierarchical cluster analysis The results of the faunal divisions according to the cluster analysis were illustrated in a geographic information system(GIS).When 19 geographical units were clustered into two clusters,the boundary of the two clusters corresponded to that of the Palearctic and Indomalayan(Oriental)realms in the recent division of Chinese fauna.When the geographical units were clustered into eight clusters,the sub-region Southern Yunnan Hilly became an idiographic cluster.As a result,Southern Yunnan hilly should be regarded as a region rather than a sub-region at the same level as Southwest region,Central China region and South China region.The differences in the distribution patterns of birds and mammals among the units in the Indomalayan(Oriental)realm were more complicated than those in Palearctic realm.Afew differences of the cluster analysis results based on the faunal types were found between the bird and mammal species.These differences might result from the different ecological and geographical distribution patterns of these two animal categories.
