Centre for Invasion Biology, Department of Botany & Zoology, Stellenbosch University, Private Bag X1, Stellenbosch, 7602, South Africa.
Mol Ecol. 2013 Dec;22(23):5793-804. doi: 10.1111/mec.12538. Epub 2013 Nov 6.
Conventional wisdom predicts that sequential founder events will cause genetic diversity to erode in species with expanding geographic ranges, limiting evolutionary potential at the range margin. Here, we show that invasive European starlings (Sturnus vulgaris) in South Africa preserve genetic diversity during range expansion, possibly as a result of frequent long-distance dispersal events. We further show that unfavourable environmental conditions trigger enhanced dispersal, as indicated by signatures of selection detected across the expanding range. This brings genetic variation to the expansion front, counterbalancing the cumulative effects of sequential founding events and optimizing standing genetic diversity and thus evolutionary potential at range margins during spread. Therefore, dispersal strategies should be highlighted as key determinants of the ecological and evolutionary performances of species in novel environments and in response to global environmental change.
传统观点认为，在地理分布范围不断扩大的物种中，顺序的起源事件会导致遗传多样性逐渐减少，从而限制了分布范围边缘的进化潜力。在这里，我们表明，南非的入侵欧洲椋鸟（Sturnus vulgaris）在其分布范围扩大的过程中保留了遗传多样性，这可能是由于频繁的长距离扩散事件所致。我们进一步表明，不利的环境条件会引发更强烈的扩散，这可以通过在不断扩大的分布范围中检测到的选择信号来表明。这将遗传变异带到了扩展的前沿，抵消了顺序起源事件的累积效应，从而优化了分布范围边缘的遗传多样性和进化潜力。因此，扩散策略应该被强调为物种在新环境中的生态和进化表现的关键决定因素，并应对全球环境变化。
