Department of Mathematics and Statistics, University of Helsinki, PO Box 68, FIN-00014, Helsinki, Finland.
Current address: Department of Evolutionary Biology and Environmental Studies, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland.
Evolution. 2019 Dec;73(12):2529-2537. doi: 10.1111/evo.13866. Epub 2019 Nov 5.
Functional connectivity, the realized flow of individuals between the suitable sites of a heterogeneous landscape, is a prime determinant of the maintenance and evolution of populations in fragmented habitats. While a large body of literature examines the evolution of dispersal propensity, it is less known how evolution shapes functional connectivity via traits that influence the distribution of the dispersers. Here, we use a simple model to demonstrate that, in a heterogeneous environment with clustered and solitary sites (i.e., with variable structural connectivity), the evolutionarily stable population contains strains that are strongly differentiated in their pattern of connectivity (local vs. global dispersal), but not necessarily in the fraction of dispersed individuals. Also during evolutionary branching, selection is disruptive predominantly on the pattern of connectivity rather than on dispersal propensity itself. Our model predicts diversification along a hitherto neglected axis of dispersal strategies and highlights the role of the solitary sites-the more isolated and therefore seemingly less important patches of habitat-in maintaining global dispersal that keeps all sites connected.
功能连接，即个体在异质景观适宜地点之间的实际流动，是维持和进化破碎生境中种群的主要决定因素。虽然大量文献研究了扩散倾向的进化，但通过影响扩散者分布的特征来塑造功能连接的进化方式却鲜为人知。在这里，我们使用一个简单的模型来证明，在一个具有聚类和孤立地点的异质环境中（即具有可变结构连接），进化稳定的种群包含在连接模式上存在强烈差异的菌株（局部与全局扩散），但不一定在分散个体的比例上存在差异。同样在进化分支过程中，选择主要对连接模式而不是对扩散倾向本身具有破坏性。我们的模型预测了沿着一个迄今为止被忽视的扩散策略轴的多样化，并强调了孤立地点的作用——这些孤立的、因此看似不太重要的栖息地斑块——在维持使所有地点保持连接的全局扩散方面的作用。
