集合种群动态对生境毁坏空间异质性的响应

Metapopulation dynamics response to the spatial heterogeneity of habitat destruction

首次将分形几何(Fractal geometry)与元胞自动机(Cellular automata)相结合,研究了破碎化生境中集合种群的空间分布格局动态,以及集合种群动态对生境毁坏空间异质性的响应。研究发现:(1)各个物种种群在生境中的分布具有很好的分形特征,物种的计盒维数(Box dimension)不仅可以很好地反映种群的空间分布结构,也能很好地反映种群动态。(2)如果将空间因素考虑进来的话,生境毁坏的灭绝债务(Time debt)将大于空间隐含模式所模拟的结果。(3)物种灭绝同时存在强物种灭绝和弱物种灭绝。并且只有在生境随机毁坏下,才与空间隐含的模拟结果比较接近,即强物种中将是最强物种率先灭绝。而在边缘毁坏这种比较集中成块的开发方式下,将是较强的物种灭绝。(4)边缘毁坏相对随机毁坏有利于物种,尤其是弱物种的长期续存。

The speeds of species extinction reach the climax in history and earth is facing the greatest mass extinction during the past 6500 millions. In the meanwhile, Habitat destruction is the most pervasive and pernicious human impact on other species and the major cause of biodiversity loss. Therefore, there are many studies on the effects of habitat destruction on species diversity through spatial implicitly models or spatial explicitly ones. Because the pattern of habitat destruction in real landscape is random, it can not be ignored. Spatial explicitly models, especially for cellular automata, are widely used because of their consideration of spatial patterns. However, few studies have studied the dynamics of population spatial patterns in fragmented habitat through fractal geometry. So, we have studied the dynamics of the population spatial patterns in fragmented habitat and metapopulation dynamics response to the spatial heterogeneity of habitat destruction through the integration of cellular automata and fractal geometry at the first time. The results show that ： （ 1 ） the spatial distribution patterns of population have fractal characteristics. Box dimension can represent not only population spatial patterns, but also population dynamics. （2） By taking spatial factors into consideration, the extinction debt will be much greater. （3） There is the extinction not only of superior competitors, but also of inferior ones. Only under random destruction, will the results （i. e. , the best competitor will go extinct at first. ） be similar to those under spatial implicitly models. It will be the third best competitor that goes extinct first. （4） Aggregated destruction such as edge destruction is more favorable to species persistence than random destruction, especially for inferior competitors.