A THREE-VARIABLE ECOSYSTEM MODEL AND ITS NUMERICAL SIMULATIONS
A simplified model of grassland ecosystem with single species is developed to inves-tigate the roles of precipitation and vegetation-soil interactions in shaping grass-land. The model consists of three variables: the biomass of living grass, biomass of wilted grass, and soil water content. The influences of atmospheric and soil factors are all assumed to be known and prescribed by fixed parameters. Precipitation is the only climatic driving force and is independent of system. It is time independent or possesses seasonal variation in the model, and the system always approaches to an equilibrium state (either a fixed point or a limit cycle). The results of numeri-cal simulations show that the ecosystem is a desert when the precipitation is lower than critical value, a grassland when the precipitation is larger than a another critical value, and can be either a grassland or a desert when the precipitation is in the middle of this two values. This implies that abrupt transition from grassland to desert can occur even if the precipitation changes smoothly in space. This theory and the numerical results can successfully explain the state of temperate grassland ecosystem in the Inner Mongolia of China.
XIAODONG ZENG SAMUEL S.P. SHEN XUBIN ZENG QING-CUN ZENG
Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, China Institute of Biophysic Dept of Mathematical and Statistical Sciences, University of Alberta, Edmonton, Canada Dept of Atmospheric Sciences, the University of Arizona, Tucson, USA Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, China
国际会议
The Joint Conference of ICCP6 and CCP2003(第6届国际计算伦理会议)
北京
英文
284-287
2004-05-23（万方平台首次上网日期，不代表论文的发表时间）