Terrestrial Ecology Unit, Department of Biology, Ghent University, K.L. Ledeganckstraat 35, B-9000 Ghent, Belgium.
Mol Ecol. 2011 May;20(9):1829-44. doi: 10.1111/j.1365-294X.2011.05028.x. Epub 2011 Feb 24.
Habitat fragmentation can restrict geneflow, reduce neighbourhood effective population size, and increase genetic drift and inbreeding in small, isolated habitat remnants. The extent to which habitat fragmentation leads to population fragmentation, however, differs among landscapes and taxa. Commonly, researchers use information on the current status of a species to predict population effects of habitat fragmentation. Such methods, however, do not convey information on species-specific responses to fragmentation. Here, we compare levels of past population differentiation, estimated from microsatellite genotypes, with contemporary dispersal rates, estimated from multi-strata capture-recapture models, to infer changes in mobility over time in seven sympatric, forest-dependent bird species of a Kenyan cloud forest archipelago. Overall, populations of sedentary species were more strongly differentiated and clustered compared to those of vagile ones, while geographical patterning suggested an important role of landscape structure in shaping genetic variation. However, five of seven species with broadly similar levels of genetic differentiation nevertheless differed substantially in their current dispersal rates. We conclude that post-fragmentation levels of vagility, without reference to past population connectivity, may not be the best predictor of how forest fragmentation affects the life history of forest-dependent species. As effective conservation strategies often hinge on accurate prediction of shifts in ecological and genetic relationships among populations, conservation practices based solely upon current population abundances or movements may, in the long term, prove to be inadequate.
生境破碎化会限制基因流动，降低局域有效种群大小，并增加小而孤立的生境残余物中的遗传漂变和近交。然而，生境破碎化导致种群破碎化的程度因景观和分类群而异。通常，研究人员利用物种当前状况的信息来预测生境破碎化对种群的影响。然而，这些方法并没有传达物种对破碎化的具体反应的信息。在这里，我们比较了过去种群分化程度，根据微卫星基因型估计，与当代扩散率，根据多层次捕获-再捕获模型估计，以推断七种肯尼亚云森林群岛森林依赖鸟类的时间推移上的移动性变化。总体而言，与迁徙物种相比，定居物种的种群分化和聚类程度更强，而地理格局表明景观结构在塑造遗传变异方面起着重要作用。然而，在具有相似遗传分化水平的七个物种中，有五个物种的当前扩散率却有很大差异。我们得出的结论是，在没有参考过去种群连通性的情况下，后破碎化时代的迁徙能力可能不是衡量森林破碎化如何影响森林依赖物种生活史的最佳预测指标。由于有效的保护策略通常取决于对种群之间生态和遗传关系变化的准确预测，因此仅基于当前种群数量或运动的保护实践从长远来看可能证明是不够的。
