Smith Thomas B, Milá Borja, Grether Gregory F, Slabbekoorn Hans, Sepil Irem, Buermann Wolfgang, Saatchi Sassan, Pollinger John P
Center for Tropical Research, Institute of the Environment, University of California Los Angeles, 619 Charles Young Dr, Los Angeles, CA 90095, USA.
Mol Ecol. 2008 Jan;17(1):58-71. doi: 10.1111/j.1365-294X.2007.03478.x. Epub 2007 Sep 12.
Relatively little attention has been directed towards understanding the impacts of human disturbance on evolutionary processes that produce and maintain biodiversity. Here, we examine the influence of anthropogenic habitat changes on traits typically associated with natural and sexual selection in the little greenbul (Andropadus virens), an African rainforest bird species. Using satellite remote-sensing and field survey data, we classified habitats into nonhuman-altered mature and human-altered secondary forest. Mature rainforest consisted of pristine rainforest, with little or no human influence, and secondary forest was characterized by plantations of coffee and cacao and high human impacts. Andropadus virens abundance was higher in secondary forest, and populations inhabiting mature rainforest were significantly larger in wing and tarsus length and bill size; characters often correlated with fitness. To assess the extent to which characters important in sexual section and mate choice might be influenced by habitat change, we also examined differences in plumage colour and song. Plumage colour and the variance in plumage luminance were found to differ between forest types, and song duration was found to be significantly longer in mature forest. The possible adaptive significance of these differences in traits is discussed. Despite relatively high levels of gene flow across habitats, amplified fragment length polymorphism analysis revealed that a small proportion of high-F(ST) loci differentiated mature from secondary forest populations. These loci were significant outliers against neutral expectations in a simulation analysis, suggesting a role for divergent selection in differentiation across habitats. A distance-based redundancy analysis further showed that forest type as defined by remote-sensing variables was significantly associated with genetic dissimilarities between habitats, even when controlling for distance. The observed shifts in morphology, plumage and song were consistent with divergent selection on heritable variation, but a role for plasticity cannot be ruled out. Results suggest that anthropogenic habitat changes may have evolutionary consequences, with implications for conservation and restoration.
相对而言，人们很少关注人类干扰对产生和维持生物多样性的进化过程的影响。在此，我们研究了人为栖息地变化对一种非洲雨林鸟类——小青背织雀（Andropadus virens）中通常与自然选择和性选择相关的性状的影响。利用卫星遥感和实地调查数据，我们将栖息地分为未受人类改变的成熟森林和受人类改变的次生林。成熟雨林由几乎没有或没有人类影响的原始雨林组成，次生林的特征是咖啡和可可种植园以及较高的人类影响。小青背织雀在次生林中的数量较多，而栖息在成熟雨林中的种群在翅长、跗跖长和喙大小方面明显更大；这些特征通常与适应性相关。为了评估在性选择和配偶选择中重要的性状可能受栖息地变化影响的程度，我们还研究了羽毛颜色和鸣声的差异。发现森林类型之间的羽毛颜色和羽毛亮度方差存在差异，并且成熟森林中的鸣声持续时间明显更长。讨论了这些性状差异可能的适应性意义。尽管不同栖息地之间存在相对较高水平的基因流动，但扩增片段长度多态性分析表明，一小部分高F(ST)位点区分了成熟森林和次生林种群。在模拟分析中，这些位点是偏离中性预期的显著异常值，表明趋异选择在不同栖息地分化中发挥了作用。基于距离的冗余分析进一步表明，即使在控制距离的情况下，由遥感变量定义的森林类型与栖息地之间的遗传差异显著相关。观察到的形态、羽毛和鸣声的变化与对可遗传变异的趋异选择一致，但不能排除可塑性的作用。结果表明，人为栖息地变化可能具有进化后果，对保护和恢复具有重要意义。
