Department of Ecology, Evolution and Environmental Biology, Columbia University, 1200 Amsterdam Ave, New York, NY, 10027, USA.
Ecol Lett. 2018 Oct;21(10):1496-1504. doi: 10.1111/ele.13130. Epub 2018 Aug 7.
Although individual-level variation (IV) is ubiquitous in nature, it is not clear how it influences species coexistence. Theory predicts that IV will hinder coexistence but empirical studies have shown that it can facilitate, inhibit, or have a neutral effect. We use a theoretical model to explore the consequences of IV on local and regional species coexistence in the context of spatial environmental structure. Our results show that individual variation can have a positive effect on species coexistence and that this effect will critically depend on the spatial structure of such variation. IV facilitates coexistence when a negative, concave-up relationship between individuals' competitive response and population growth rates propagates to a disproportionate advantage for the inferior competitor, provided that each species specialises in a habitat. While greater variation in the preferred habitat generally fosters coexistence, the opposite is true for non-preferred habitats. Our results reconcile theory with empirical findings.
虽然个体变异（IV）在自然界中普遍存在，但它如何影响物种共存还不清楚。理论预测 IV 会阻碍共存，但实证研究表明它可以促进、抑制或产生中性影响。我们使用一个理论模型来探讨个体变异在空间环境结构背景下对本地和区域物种共存的影响。我们的结果表明，个体变异可以对物种共存产生积极影响，而且这种影响将取决于这种变异的空间结构。如果个体的竞争反应和种群增长率之间存在负的、凸向上的关系，并且这种关系对劣势竞争者产生不成比例的优势，那么个体变异就会促进共存，只要每个物种都专门适应一个栖息地。虽然偏好栖息地的更大变异通常会促进共存，但对于非偏好栖息地则相反。我们的结果调和了理论和实证发现。
