Statistical Properties of Multispecies Competition Ecosystems Subjected to Dichotomous Noises

【摘要】 <正> We investigate statistical properties of multispecies competition ecosystems subjected to both symmetricand asymmetric dichotomous noises.The expression of the stationary probability distribution function（SPDF）isanalytically derived by means of mean-held approximation,and verified by stochastic simulations.The results indicatethat:（i）A noise amplitude（a-0）,a noise autocorrelation time（τ₀）and a noise symmetry parameter（k）all can affectthe SPDF;（ii）There is an optimal τ₀,which makes the mean value of population density be maximal,near which atransition takes place,i.e.,the stationary mean value of species density(〈x〉_st)suddenly falls to a lower constant;（iii）As k decreases,the maximum of 〈x〉_stand the optimal τ₀ increase.The parameter planes of τ₀ — a₀² and τ₀-k for thetransition are plotted.更多还原

【Abstract】 We investigate statistical properties of multispecies competition ecosystems subjected to both symmetric and asymmetric dichotomous noises.The expression of the stationary probability distribution function（SPDF）is analytically derived by means of mean-held approximation,and verified by stochastic simulations.The results indicate that:（i）A noise amplitude（a-0）,a noise autocorrelation time（τ₀）and a noise symmetry parameter（k）all can affect the SPDF;（ii）There is an optimal τ₀,which makes the mean value of population density be maximal,near which a transition takes place,i.e.,the stationary mean value of species density(〈x〉_st)suddenly falls to a lower constant;（iii） As k decreases,the maximum of 〈x〉_stand the optimal τ₀ increase.The parameter planes of τ₀ — a₀² and τ₀-k for the transition are plotted.更多还原