Economo Evan P, Keitt Timothy H
Section of Integrative Biology, University of Texas at Austin, 1 University Station C0930, Austin, TX 78712, USA.
Ecol Lett. 2008 Jan;11(1):52-62. doi: 10.1111/j.1461-0248.2007.01126.x. Epub 2007 Nov 15.
Biologists seek an understanding of the processes underlying spatial biodiversity patterns. Neutral theory links those patterns to dispersal, speciation and community drift. Here, we advance the spatially explicit neutral model by representing the metacommunity as a network of smaller communities. Analytic theory is presented for a set of equilibrium diversity patterns in networks of communities, facilitating the exploration of parameter space not accessible by simulation. We use this theory to evaluate how the basic properties of a metacommunity - connectivity, size, and speciation rate - determine overall metacommunity gamma-diversity, and how that is partitioned into alpha- and beta-components. We find spatial structure can increase gamma-diversity relative to a well-mixed model, even when theta is held constant. The magnitude of deviations from the well-mixed model and the partitioning into alpha- and beta-diversity is related to the ratio of migration and speciation rates. gamma-diversity scales linearly with metacommunity size even as alpha- and beta-diversity scale nonlinearly with size.
生物学家致力于理解空间生物多样性模式背后的过程。中性理论将这些模式与扩散、物种形成和群落漂移联系起来。在此，我们通过将集合群落表示为较小群落的网络来推进空间明确的中性模型。针对群落网络中的一组平衡多样性模式提出了解析理论，便于探索模拟无法触及的参数空间。我们运用该理论评估集合群落的基本属性——连通性、规模和物种形成速率——如何决定集合群落的总体伽马多样性，以及伽马多样性如何被划分为阿尔法和贝塔成分。我们发现，即使θ保持不变，相对于完全混合模型，空间结构也能增加伽马多样性。与完全混合模型的偏差幅度以及向阿尔法和贝塔多样性的划分与迁移率和物种形成速率的比率有关。伽马多样性与集合群落规模呈线性关系，而阿尔法和贝塔多样性与规模呈非线性关系。
