Allee效应对具有生境恢复的集合种群的影响

摘要

Allee效应与种群的灭绝密切相关,其研究对生态保护和管理至关重要.Allee效应对物种续存是潜在的干扰因素,濒危物种更容易受其影响,可能会增加生存于生境破碎化斑块的濒危物种的死亡风险,因此研究Allee效应对种群的动态和续存的影响是必要的.从包含由生物有机体对环境的修复产生的Allee效应的集合种群模型出发,引入由其他机制形成的Allee效应,建立了常微分动力系统模型和基于网格模型的元胞自动机模型.通过理论分析和计算机模拟表明:(1)强Allee效应不利于具有生境恢复的集合种群的续存;(2)生境恢复有利于种群续存;(3)局部扩散影响了集合种群的空间结构、动态行为和稳定性,生境斑块之间的局部作用将会减缓或消除集合种群的Allee效应,有利于集合种群的续存.%Understanding Allee effects is important for ecological conservation and management because it is strongly related to population extinction.The Allee effect is a destabilizing factor in species persistence,and endangered species are more susceptible to the effect as it will increase the risk of extinction associated with living in fragmented habitats.Many mechanisms may account for the Allee effect,such as organism-environment feedback,mate-finding limitations,cooperative defense,social dysfunction,inbreeding depression,and predator avoidance or defense.Because of various ecological mechanisms leading to the Allee effect,a large amount of experimental evidence in recent years has indicated that species have been subjected to multiple Allee effects.Therefore,it is necessary to study the influence of multiple Allee effects on population dynamics and persistence;however,few theoretical studies have been performed on multiple Allee effects.In this study,we began by assuming that metapopulations experience Allee effects caused by organism-environment feedback and also induced the Allee effect through other ecological mechanisms.We constructed a differential dynamical system and we used phase-plane analysis and numerical solutions to illustrate equilibriums and their system stability.Furthermore,we discussed and simulated the influences of the Allee effect on the spatial distribution of a metapopulation by using a cellular automata model based on a lattice model.The results obtained by theoretical analysis and computer simulations suggested that a strong Allee effect could markedly increase the extinction risk for a metapopulation with habitat restoration;(2)Habitat restoration is favorable for population persistence;and (3) local dispersal influences the spatial structure,dynamics,and stability of a population.Our simulations,which explicitly consider spatial structure,also demonstrated that local interaction among habitat patches can greatly mitigate the Allee effect and is favorable for the persistence of a metapopulation.This result suggests that limited local dispersal may be a stabilizing factor.