生境破坏的模式对集合种群动态和续存的影响

The effect of habitat destruction pattern on the dynamics and persistence of metapopulation

构建了空间关联的集合种群模型,该模型不但包含了种群的空间结构信息,而且引入了破坏生境的全局密度和局部密度两个指标,它们描述了破坏生境的模式。模型揭示了破坏生境的空间分布格局复杂地影响了集合种群的动态和续存,破坏和未破坏生境斑块的均匀混合不利于集合种群的增长和续存,而生境类型聚集分布可以促进集合种群的快速增长和长期续存;对于两种斑块类型相对均匀混合的生境来说,均匀场假设可能会高估集合种群的续存,对于相对斑块类型高度聚集的生境,均匀场假设可能会低估集合种群的续存;物种的迁移范围也会影响集合种群的续存,迁移范围越大的物种越容易抵御生境的破坏而免遭灭绝。这意味着在生物保护中不能仅仅考虑生境的恢复和斑块质量的改善,生境结构的构建也是很重要的,加强生境斑块之间的连通性也有利于物种的长期续存。

A spatial correlated model for metapopulation has been constructed, which not only includes population information about spatial struetutre, but also introduces the global density and local density of distructed habitat. Model reveals the spatial distribution pattern of destructed habitat profoundly effect the dynamics and persistence of metapopulation. The mixed distribution of two habitat types makes against metapopulation increase and persistence and mean-field assumption may overestimate the persistence of metapopulation in mixed habitat, but clustering distribution will promote its increase and persistence and mean-field assumption may underestimate the persistence of metapopulation in clustering habitat. Metapopulation persisitence is also affected by species migration. The longer migration distance, the more possibly species resists extinction from habitat destruction. All the resluts show that not only the number of destructed habitat is a main cause incuring metapopulation extinction but also the spatial distribution pattern of destruct landscape profoundly effect the dynamics and persistence of metapopulation. All these results show that it is important to costruct the connectivity among patches although habitat restoration and habitat quality improvement is necessary.