内外涨落效应对单一种群数量的影响

Effects of Internal and External Fluctuations on the Quantity of Single Biologic Species

通过分析随机的佛霍尔斯特方程 ,讨论了内外涨落对单一物种演化的影响 .即 :当涨落不可忽略 ,即使繁殖率小于死亡率 ,种群物种数量仍有可能保持在一个较小的规模 .当增长率小于零 ,内涨落对物种数量的定态几率分布曲线的影响更明显 ;当增长率大于零 。

Effects of internal and external fluctuations on evolvement of a biologic species are studied. Discussing the stochastic Verhulst equation, the results show that the quantity of biologic species retains a little range because of the effects of fluctuations, Even though the procreation coefficient is less than the death rate. When the increase rate is less than zero, effects of internal fluctuations on the stationary probability distribution of the biologic species are obvious. When the increase rate is more than zero, effects of external fluctuations on the stationary probability distribution of the biologic species are larger.