环境波动对生命历程模型的影响

目的应用随机动力学理论模拟环境变化对地理学中生命历程模型的影响,揭示环境变化下生命历程模型的稳定性。方法应用Langevin方程和Fokker-Planck方程计算出系统稳态的概率分布函数。结果当环境波动对地理生命体各环节影响无关联时,环境波动的增强促使地理生命体的数量减小,系统的稳定性削弱。当随机波动增大到一定程度会诱发地理生命体进入灭绝态,促使地理生命体走向衰亡。存在关联时,正负关联产生不同的效应。随着关联强度的增大,负关联时地理生命体的数量减小,但系统的稳定性增强,表明这种关联会抑制地理生命体的发展;相反正关联时,地理生命体数量增加,但系统的稳定性削弱,表明这种关联会促进地理生命体的发展。结论本文研究结果对了解地理生命体在随机波动环境下的发展规律提供了理论依据。

The influence of environmental fluctuations on life course model

Purposes-To simulate the impacts of the environmental fluctuation on the "life cycle" model in the geography by making using the stochastic dynamics and to analyze the stability of this model.Methods-The steady probability distribution function is obtained based on the Langevin Equation and the Fokker-Planck Equation.Results-Under no correlation between growth rate and decay rate, with the increase of the environmental fluctuation, the stability of the system is weaken, and the number of the geographical life decreases.Under the presence of the correlation between growth rate and the decay rate, in the case of negative correlation, with the increase of correlation intensity, the stability of the system is enhanced and the number of the geographical life decreases.On the contrary, in the case of positive correlation, with the increase of correlation intensity, the stability of the system is weaken and the number of the geographical life decreases;the effects of the positive correlation and the negative correlation present an opposite role.Conclusions-The results will provide some theoretic supports for the development rules of the geographical life under the fluctuation environment.