Zoology, School of Natural Sciences, Trinity College Dublin, Dublin 2, Ireland;
School of Agriculture and Food Science, University of Queensland, Gatton, 4343, Australia.
Proc Natl Acad Sci U S A. 2020 Feb 25;117(8):4218-4227. doi: 10.1073/pnas.1915848117. Epub 2020 Feb 7.
When plants establish outside their native range, their ability to adapt to the new environment is influenced by both demography and dispersal. However, the relative importance of these two factors is poorly understood. To quantify the influence of demography and dispersal on patterns of genetic diversity underlying adaptation, we used data from a globally distributed demographic research network comprising 35 native and 18 nonnative populations of Species-specific simulation experiments showed that dispersal would dilute demographic influences on genetic diversity at local scales. Populations in the native European range had strong spatial genetic structure associated with geographic distance and precipitation seasonality. In contrast, nonnative populations had weaker spatial genetic structure that was not associated with environmental gradients but with higher within-population genetic diversity. Our findings show that dispersal caused by repeated, long-distance, human-mediated introductions has allowed invasive plant populations to overcome environmental constraints on genetic diversity, even without strong demographic changes. The impact of invasive plants may, therefore, increase with repeated introductions, highlighting the need to constrain future introductions of species even if they already exist in an area.
当植物在其原生范围之外建立时，它们适应新环境的能力受到种群动态和扩散的影响。然而，这两个因素的相对重要性还了解甚少。为了量化种群动态和扩散对适应基础上遗传多样性模式的影响，我们使用了一个由 35 个本地和 18 个非本地种群组成的全球分布的种群动态研究网络的数据。物种特异性模拟实验表明，扩散将在局部尺度上稀释种群动态对遗传多样性的影响。在欧洲本土范围内的种群与地理距离和降水季节性有关，具有强烈的空间遗传结构。相比之下，非本地种群的空间遗传结构较弱，与环境梯度无关，而与种群内遗传多样性较高有关。我们的研究结果表明，由于反复的、远距离的、人为介导的引入而导致的扩散，使得入侵植物种群能够克服遗传多样性对环境的限制，即使没有强烈的种群动态变化。因此，入侵植物的影响可能会随着重复引入而增加，这凸显了即使在一个地区已经存在物种，也需要限制未来的引入。
