Baskett Marissa L, Weitz Joshua S, Levin Simon A
Department of Ecology and Evolutionary Biology, Princeton University, Princeton, New Jersey 08544, USA.
Am Nat. 2007 Jul;170(1):59-78. doi: 10.1086/518184. Epub 2007 May 22.
The fragmentation of an environment into developed and protected areas may influence selection pressure on dispersal by increasing the chance of moving from a favorable to an unfavorable habitat. We theoretically explore this possibility through two cases: (1) marine systems in which reduced predation and/or increased feeding drive the evolution of planktonic larval duration and (2) more generally, where stochasticity in reproductive yield drives the evolution of the proportion of offspring dispersing. Model results indicate that habitat fragmentation generally shifts selection pressure toward reduced dispersal, particularly when areas outside reserves are uninhabitable. However, shifts to increased dispersal may occur when temporal heterogeneity is the primary selective force and constant-quota harvest occurs outside reserves. In addition, model results suggest the potential for changes in the genetic variability in dispersal after habitat fragmentation. The predicted evolutionary changes in dispersal will depend on factors such as the relative genetic and environmental contributions to dispersal-related traits and the extent of anthropogenic impacts outside reserves. If the predicted evolutionary changes are biologically attainable, they may suggest altering current guidelines for the appropriate size and spacing of marine reserves necessary to achieve conservation and fisheries goals.
将一个环境分割为开发区和保护区可能会增加从适宜栖息地转移到不适宜栖息地的几率，从而影响对扩散的选择压力。我们通过两个案例从理论上探讨了这种可能性：（1）海洋系统中，捕食减少和/或食物增加推动浮游幼虫期的进化；（2）更普遍的情况是，繁殖产量的随机性推动后代扩散比例的进化。模型结果表明，栖息地破碎化通常会使选择压力朝着减少扩散的方向转变，尤其是当保护区外的区域不适宜居住时。然而，当时间异质性是主要选择力且保护区外进行定额捕捞时，可能会出现扩散增加的转变。此外，模型结果表明栖息地破碎化后扩散的遗传变异性可能发生变化。预测的扩散进化变化将取决于诸如扩散相关性状的相对遗传和环境贡献以及保护区外人为影响的程度等因素。如果预测的进化变化在生物学上是可行的，那么它们可能意味着需要改变当前关于实现保护和渔业目标所需的海洋保护区适宜大小和间距的指导方针。
