Guichard Frédéric
Department of Biology, McGill University, 1205 Penfield, Montreal, Quebec, Canada H3A 1B1.
Proc Biol Sci. 2005 Aug 7;272(1572):1571-6. doi: 10.1098/rspb.2005.3118.
Species interactions and connectivity are both central to explaining the stability of ecological communities and the problem of species extinction. Yet, the role of species interactions for the stability of spatially subdivided communities still eludes ecologists. Ecological models currently address the problem of stability by exploring the role of interaction strength in well mixed habitats, or of connectivity in subdivided communities. Here I propose a unification of interaction strength and connectivity as mechanisms explaining regional community stability. I introduce a metacommunity model based on succession dynamics in coastal ecosystems, incorporating limited dispersal and facilitative interactions. I report a sharp transition in regional stability and extinction probability at intermediate interaction strength, shown to correspond to a phase transition that generates scale-invariant distribution and high regional stability. In contrast with previous studies, stability results from intermediate interaction strength only in subdivided communities, and is associated with large-scale (scale-invariant) synchrony. These results can be generalized to other systems exhibiting phase transitions to show how local interaction strength can be used to resolve the link between regional community stability and pattern formation.
物种相互作用和连通性对于解释生态群落的稳定性以及物种灭绝问题都至关重要。然而，物种相互作用对空间细分群落稳定性的作用仍然让生态学家难以捉摸。目前的生态模型通过探讨相互作用强度在充分混合栖息地中的作用，或者连通性在细分群落中的作用来解决稳定性问题。在此，我提出将相互作用强度和连通性统一起来，作为解释区域群落稳定性的机制。我引入了一个基于沿海生态系统演替动态的集合群落模型，纳入了有限扩散和促进性相互作用。我报告了在中等相互作用强度下区域稳定性和灭绝概率的急剧转变，这表明对应于一个产生尺度不变分布和高区域稳定性的相变。与之前的研究不同，稳定性仅在细分群落中由中等相互作用强度产生，并且与大规模（尺度不变）同步相关。这些结果可以推广到其他表现出相变的系统，以展示如何利用局部相互作用强度来解析区域群落稳定性与模式形成之间的联系。
