Annual Cycle of Brandt's Vole (Microtus brandti) and Succession of Rodent Community in Xilinguole Grasslands

The population data of rodents in Narenbaolige Sumu,Abaga Banner,Inner Mongolia during 1979-1997 showed annual cyclical fluctuations of Microtus brandti population to a certain degree by cycling index (S).There were 10 rodent species,with M.brandti (88.45%) and Ochotona daurica (5.37%) in 1989-1997.There were positive correlation relationships among the total densities (the sum of population densities of rodents in unit area),density of M.brandti and O.daurica (P=0.0001).The regression model was:the total densities=0.8806+1.0048 (density of M.brandti)+0.8779 (density of O.dauricus) (P=0.0001).The diversity and evenness of rodents were influenced significantly by the density of M.brandti.Absolute dominant species was M.brandti in rodent community during 1970-1997.