Multispecies Coexistence without Diffuse Competition; or, Why Phylogenetic Signal and Trait Clustering Weaken Coexistence
Multispecies Coexistence without Diffuse Competition; or, Why Phylogenetic Signal and Trait Clustering Weaken Coexistence
复制标题
多物种共存，无分散竞争；
作者：
S. Stump
相关和表型相似的物种往往比不相关和不同的物种竞争更激烈。对于这种复杂的相互作用在社区一级的影响，人们知之甚少。在这里，我们研究他们如何影响社区动态不同的扩散相互作用（竞争平等与所有异种）。我们得出的结果，适用于许多形式的密度依赖模型，也研究了具体情况下使用的森林动态的网站占用模型。结果表明，非扩散竞争产生了扩散竞争下不存在的三种效应：一是中心生态位效应，即如果一个物种与多个竞争者有较高的生态位重叠，则其平均适合度降低;第二，共同竞争者效应-如果一个物种与更常见的物种有高的生态位重叠，那么它的平均适合度就会降低（这两种效应通常是均衡的，因为更有利的生态位可能包含更多的物种和更丰富的物种）;最后，群落再分配效应-当一个物种福尔斯密度降低时，其竞争对手的相对丰富度将发生变化，从而改变其恢复能力。群落再分配效应通常会破坏共存，因为群落通常会被入侵者最接近的竞争者所控制。这项研究提供了测量这些影响在该领域的指示和分析系统发育信号，基于性状的生态位轴，和其他形式的非扩散竞争影响共存的框架。
Related and phenotypically similar species often compete more strongly than unrelated and dissimilar species. Much is unknown about the community-level implications of such complex interactions. Here, we study how they affect community dynamics differently from diffuse interactions (competing equally with all heterospecifics). We derive results for a model that applies to many forms of density dependence and also examine specific cases using a site-occupancy model of forest dynamics. The results indicate that nondiffuse competition produces three effects that will not occur under diffuse competition: first, the central niche effect—if a species has high niche overlap with several competitors, then its average fitness is reduced; second, the common competitor effect—if a species has high niche overlap with more common species, then its average fitness is reduced (these two effects are usually equalizing, because more favorable niches are likely to contain more species and more abundant species); and, finally, the community redistribution effect—when a species falls to low density, the relative abundance of its competitors will change, altering its ability to recover. The community redistribution effect usually undermines coexistence, because the community will usually become dominated by an invader’s closest competitors. This study provides both instructions for measuring these effects in the field and a framework for analyzing how phylogenetic signal, trait-based niche axes, and other forms of nondiffuse competition affect coexistence.