关键词: 川西平原, 啮齿动物, 群落动态, 趋势, 周期性

Abstract: The time series analysis method was applied to character the trends and periodicity of the 3 variables of a 8-species rodent community in the Western Sichuan Plain , including biomass , Shannon index and Simpson index. Results suggest that : (1) Fluctuations of the 3 variables all showed increasing trends. The trend of biomass is parabola function , Shannon index and Simpson index are exponential and sine functional respectively , and (2) biomass showed one-year periodicity. The annual periodicity of the variable is synchronized with growth and harvest of rice-wheat , rice-rape , or aize-sweet-potato in subtropical agriculture ecosystem in Sichuan. The above adaptive traits resulting from coexistence of rodents and people probably make the rodents respond to cultivation quickly , such as environmental changes like yield increasing , so that increasing trends of 3 community variables were observed. Or the 3 community variables may be increased during the increasing period of their natural fluctuations. In order to
characterize ecologically we need long-term study of the community.

Key words: Community dynamics, Periodicity, Rodents, Trend, Western Sichuan Plain