Division of Aquatic Ecology and Evolution, Institute of Ecology and Evolution, University of Bern, Baltzerstrasse 6, CH-3012 Bern, Switzerland.
Nature. 2012 Feb 15;482(7385):357-62. doi: 10.1038/nature10824.
Species diversity can be lost through two different but potentially interacting extinction processes: demographic decline and speciation reversal through introgressive hybridization. To investigate the relative contribution of these processes, we analysed historical and contemporary data of replicate whitefish radiations from 17 pre-alpine European lakes and reconstructed changes in genetic species differentiation through time using historical samples. Here we provide evidence that species diversity evolved in response to ecological opportunity, and that eutrophication, by diminishing this opportunity, has driven extinctions through speciation reversal and demographic decline. Across the radiations, the magnitude of eutrophication explains the pattern of species loss and levels of genetic and functional distinctiveness among remaining species. We argue that extinction by speciation reversal may be more widespread than currently appreciated. Preventing such extinctions will require that conservation efforts not only target existing species but identify and protect the ecological and evolutionary processes that generate and maintain species.
种群减少和通过渐渗杂交导致的物种形成逆转。为了研究这些过程的相对贡献，我们分析了来自 17 个前阿尔卑斯山欧洲湖泊的重复白鱼辐射的历史和当代数据，并使用历史样本重建了遗传物种分化随时间的变化。在这里，我们提供的证据表明，物种多样性是对生态机会的响应而进化的，而富营养化通过减少这种机会，通过物种形成逆转和种群减少导致了灭绝。在整个辐射中，富营养化的程度解释了物种丧失的模式以及剩余物种之间遗传和功能独特性的水平。我们认为，通过物种形成逆转的灭绝可能比目前人们所认识到的更为普遍。防止这种灭绝需要保护工作不仅针对现有物种，还要确定和保护产生和维持物种的生态和进化过程。
