关键词: 共存, 荒漠, 周期性, 种群密度, 啮齿动物, 季节性

Abstract: In this paper time series methods are applied to analyse seasonality，trends and periodicity of population density on 11 species of rodents in the Chihuahuan Desert of North Ameriea，and a seasonality．index is developed to evaluate the seasonality of population density as well．The results reveal that Chaetodipus penicillatus has the most significant seasonality，but two species in genus Peromygcus and Perognathus flavus have the most ambiguous seasonality of all, There are trends in population density of7 pecies．Popalation density of 6 species tends to increase，on the contrary that of Dipodomys spetctabilis trends to deerease during the study period．Weind out a 4-year period in fluctuation of population density of Dipodomys merriami，a 4．5-year period in Peromyscus maniculatus and a 1-year period in the other three species includingChaetodipus penicillatus, Reithrodontomys megalaotis and Onychomys leucogaster．A comparative study on seasonality，trends and periodicity shows that population dynamics 11 species varies widely and lacks clear and consistent patterns with their phyloge-netieal history．We suggest that it is diverse seasonality，trends and periodicity patterns that keep coexistence temporally in 11 species.

Key words: Coexistence, Dcsert, Periodielty, PopuIation density, Rodents, Seasonalit