Department of Ecology and Evolution, University of Chicago, Chicago, Illinois 60637, USA.
Ecology. 2011 May;92(5):1174-80. doi: 10.1890/10-0953.1.
Intransitive communities, those in which species' abilities cannot be ranked in a hierarchy, have been the focus of theoretical and empirical research, as intransitivity could help explain the maintenance of biodiversity. Here we show that models for intransitive competition embedding slightly different interaction rules can produce opposite patterns. In particular, we find that interactions in which an individual can be outcompeted by its neighbors, but cannot outcompete its neighbors, produce negative frequency dependence that, in turn, promotes coexistence. Whenever the interaction rule is modified toward symmetry (the individual and the neighbors can outcompete each other) the negative frequency dependence vanishes, producing different coexistence levels. Macroscopically, we find that asymmetric interactions yield highest biodiversity if species compete globally, while symmetric interactions favor highest biodiversity if competition takes place locally.
非传递群落，即物种之间的能力无法在等级体系中进行排序的群落，一直是理论和实证研究的焦点，因为非传递性可以帮助解释生物多样性的维持。在这里，我们表明，嵌入略有不同相互作用规则的非传递竞争模型可以产生相反的模式。特别是，我们发现，个体可以被邻居竞争淘汰，但不能淘汰邻居的相互作用，会产生负频率依赖性，从而促进共存。只要相互作用规则朝着对称性（个体和邻居可以相互竞争）进行修改，负频率依赖性就会消失，从而产生不同的共存水平。从宏观上看，如果物种在全球范围内竞争，那么非对称相互作用会产生最高的生物多样性，而如果竞争发生在局部，那么对称相互作用会产生最高的生物多样性。
