生境破坏的空间结构对集合种群动态的影响

Effect of habitat destruction structure on the dynamics of metapopulation

构建任意生境破坏结构下集合种群动态的元胞自动机模型,研究生境破坏的空间结构对集合种群全局密度及局部密度的影响.该模型不仅包括了生境破坏的空间结构,而且能够描述集合种群的空间分布模式.模型结果表明:生境破坏的空间结构复杂地影响着集合种群的全局密度和局部密度;生境破坏的混合分布增大了集合种群灭绝的风险;生境破坏的聚集分布降低了集合种群灭绝的风险.在生境破坏比例较小或较大时,集合种群全局密度和局部密度随生境破坏比例的增加而加大,随生境破坏聚集度的增加而减小,且生境破坏比例对集合种群动态的影响要大于生境破坏聚集度的影响.但在特定的情况下,即生境破坏比例在55%左右时,生境聚集度的增加可能会使集合种群的全局密度和局部密度都减小.此外,发现集合种群的局部密度存在一个阈值,当集合种群局部密度低于此值时,集合种群将无法续存.这意味着在生物保护中不能仅仅考虑生境的恢复、斑块的质量,还需要考虑生境破坏的空间结构和被保护物种的局部密度.

To study the effects of habitat destruction on metapopulation dynamics,a model for metapopulation dynamics has been constructed,based on the cellular automaton model,which includes not only metapopulation information about spatial structure,but also the global density and local density of destruction habitat.With the model reveals the spatial structure of destructed habitat profoundly affects the dynamics of metapopulation.The mixed distribution of destructed habitat and suitable habitat,the global density of destructed habitat is bigger than the local,which makes the danger of metapopulation extinction.While with clustering distribution,the global density of destructed habitat is smaller than the local,which will promote the persistence of metapopulation increase.General,the global and local density of metapopulation are in direct proportion to the global density of destructed habitat,and in inverse proportion to the local density of destructed habitat.But,with certain global density of destructed habitat,the global and local density of metapopulation decrease with the increase of the local density of destructed habitat.There is a threshold,which thelocal density of metapopulationis below,the metapopulation would extinct.All these results show that it is important to construct the connectivity among patches and the local density of metapopulation,although habitat restoration and habitat quality improvement are necessary.