Effect of noises on the stability of a metapopulation
噪声对集合种群稳定性的影响

The Levins model subjected to the noise is employed to study the stability of a metapopulation.The analytic expressions of the stationary probability distribution function and the mean extinction time of the metapopulation are obtained according to the Fokker-Planck Equation.The results show that for the case of no correlation between the additive noise and the multiplicative noise (λ= 0,λis the intensity of correlation between multiplicative and additive noise),the increase of the additive noise intensityαand the multiplicative noise intensity D weaken the stability of a metapopulation;for the case ofλ≠0,λenhances the stability of a metapopulation.For—(c—e—D)2/(AcVDa) < A < 1,A can induce the "resonance restrain" phenomenon.Meantime,there exists a critical value of D.When D is lower than the critical value,the stability of the system is enhanced.