作 者 ：林振山*,何亮
期 刊 ：生态学报 2010年 30卷 19期 页码：5245~5252
Keywords:aggregation effect, metapopulation, dynamical model,
摘 要 ：引入种群集聚度和集聚效应的概念，通过建立物种的集聚效应模型，结合经典的Tilman集合种群模式，创建了集聚效应下的集合种群动力模式。通过大量的数值模拟分析栖息地未毁坏下的集合种群演化规律与集聚效应的关系，得到：（1）即使生境没有毁坏，种群的集聚效应也会影响种群的演化。（2）集合种群系统中不同种群对集聚效应反应有异同，相同点是各种群都要经历一段准周期波动才达到平衡态。不同点是不同种群对集聚效应反应的强度不一致，竞争能力越强的种群准周期波动的振幅越大，频率越低。竞争能力越弱的种群准周期波动的振幅越小，频率越高。（3）不同的群落对集聚效应的响应也不一致。优势种群相对明显的群落对集聚效应的响应幅度相对较小。（4）在优势种群明显的群落中，集聚效应对弱物种非常不利，弱物种很有可能由于集聚效应而灭绝。（5）群落或n集合种群里的各种群的集聚效应和建群种（或最优势种）的强弱是决定景观生态序的最为重要的2个因素。（6）每个物种对不同的不适集聚程度的响应不一致。不适集聚程度越大，物种演化波动幅度越大，频率越高。
Abstract:Species distribution plays an important role in both the intraspecies competition and the interspecies competition. In order to assess the ecological effect due to the species distribution, this paper establishes the aggregation effect model by combining the Tilman′s metapopulation model on the basis of introducing the ecological concepts of the population aggregation index and the aggregation effect and constructing the metapopulation dynamical model with the aggregation effect. And then，through a bulk of numerical simulations, it analyzes the relationship between the metapopulation evolution law and its aggregation effect on condition that the habitat is not destroyed. Accordingly, it obtains the following interesting results. Firstly, even if the habitat was not destroyed, the evolution of the population could be affected by the aggregation effect. Secondly, different species of the metapopulation bear different reactions to the aggregation effect. The habitat occupied rate of every species displays quasi-periodic fluctuation to the equilibrium. However, the stronger the species is, the longer the vibrating period and the higher relative fluctuation amplitude of the habitat occupied rate. In contrast, the weaker the species is, the shorter the vibrating period and the lower relative fluctuation amplitude of habitat occupied rate. Thirdly, different communities also have different reactions to the aggregation effect. When dominated by superior population, the community tends to be less affected by the aggregation effect. Fourthly, in the community dominated by the superior population, the aggregation effect is proved to be very adverse to the weak population. They are most likely to go extinct due to such effect. Fifthly, the aggregation effect and the habitat occupied rate of the constructive species in the community are the two key factors that essentially determine the landscape ecological sequence. Finally, every species has different reactions to the different discomfortable aggregation index. The larger the aggregation index, the higher the fluctuation amplitude of the habitat occupied rate and the fluctuation frequency. The above results make sense to the theory of species conservation. Generally speaking, the ecological sequence of community is determined by the individuals′ competitive strength, breeding rate and mortality rate as well as the interspecific competitive strength. But, our research shows that it is actually the two key factors, i.e., the habitat occupied rate of the constructive species in the community and the aggregation effect, that finally determine the landscape ecological sequence. For some endangered speices, the ability to aggregate in the most comfortable aggregation index will directly determine whether it will become extinct or not. When the share of the occupied habitat of the constructive species changes, the best coping strategy for the weak species should be their prompt adjustment to the most comfortable aggregation index. At present, the share of the occupied habitat of the constructive species has been immensely increased in the synthetic ecosystem. Thus, from the numerical simulations in this paper, those weak species will inevitably go extinct in this superior species dominated community due to the very adverse aggregation effect. Therefore, both ecologists and the government should make joint efforts to carry out the following two measures. Firstly, to create advantageous conditions for the endangered or weak species to enable them gather in the most comfortable aggregation index; and secondly, to appropriately reduce the share of the occupied habitat of the constructive species in the synthetic ecosystems. Otherwise, we will get half result with twice the effort.
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