Department of Ecology and Evolutionary Biology, Rice University, Houston, TX 77005, USA.
Ecol Lett. 2009 Dec;12(12):1357-66. doi: 10.1111/j.1461-0248.2009.01390.x. Epub 2009 Oct 6.
Interactions between two populations are often defined by their interaction outcomes; that is, the positive, neutral, or negative effects of species on one another. Yet, signs of outcomes are not absolute, but vary with the biotic and abiotic contexts of interactions. Here, we develop a general theory for transitions between outcomes based on consumer-resource (C-R) interactions in which one or both species exploit the other as a resource. Simple models of C-R interactions revealed multiple equilibria, including one for species coexistence and others for extinction of one or both species, indicating that species' densities alone could determine the fate of interactions. All possible outcomes [(+ +), (+ -), (--), (+ 0), (- 0), (0 0)] of species coexistence emerged merely through changes in parameter values of C-R interactions, indicating that variation in C-R interactions resulting from biotic and abiotic conditions could determine shifts in outcomes. These results suggest that C-R interactions can provide a broad mechanism for understanding context- and density-dependent transitions between interaction outcomes.
两个种群之间的相互作用通常由它们的相互作用结果来定义；也就是说，物种之间的积极、中性或消极影响。然而，结果的迹象并不是绝对的，而是随着相互作用的生物和非生物背景而变化。在这里，我们基于消费者-资源（C-R）相互作用，为结果之间的转变发展了一个一般理论，其中一个或两个物种都将另一个物种作为资源进行利用。C-R 相互作用的简单模型揭示了多种平衡点，包括物种共存的平衡点和一个或两个物种灭绝的平衡点，这表明仅物种密度就可以决定相互作用的命运。物种共存的所有可能结果[（++），（+-），（--），（+0），（-0），（00）]仅通过 C-R 相互作用的参数值变化而出现，这表明生物和非生物条件导致的 C-R 相互作用的变化可以决定结果的转变。这些结果表明，C-R 相互作用可以为理解相互作用结果之间的上下文和密度依赖转变提供广泛的机制。
