保护区的数量和种群在集合种群水平上的续存

The influence of the number of reserves on population persistence at the metap opulation level

生境的破碎化一般被认为不利于自然种群的长期存活 .在自然保护区的设置上 ,人们一般倾向于建立一个或少数几个大的自然保护区而不是具有相同总面积的更多较小的保护区 .建立了一个既包含局域种群动态 ,又包含集合种群侵占率的模型 ,并在这两个层次上进行了计算机模拟 ,结果表明 :集合种群的存活时间随着保护区数目的增大先增大而后减小 ,即保护区的数目维持在中等大小时最有利于种群在集合种群水平上的存活 ;自然保护区大小的最优值与种群的 Allee效应有关 .

Habitat fragmentation is generally considered to be detrimental to the persistence of natural populations. In nature management, one therefore tends t o prefer one or a few large nature reserves over many small nature reserves havi ng equal total area. This paper begins with local populations and constructs a m odel that includes both local population and metapopulation dynamics. Then a sim ulation is made with computer at these two levels. The results indicate: The time to extinction of a metapopulation increases first and then decreases as th e number of reserves increases. That is to say, an intermediate reserve number e xists for which metapopulation persistence is optimal. The optimal number of reserves is affected by the Allee effect of the population.