Data from: Invasive plant species are locally adapted just as frequently and at least as strongly as native plant species

Concerns over the ecological impacts of invasive alien plant species have generated great research interest in understanding the mechanisms that underlie the capacity of such plants to occupy a broad range of habitats. It has been repeatedly suggested that rapid evolution of local adaptation to novel environments may enable invasive plants to occupy a broad range of habitats. However, the classical Darwinian view on evolution by natural selection is that the process is slow and gradual, occurring over thousands of years. Invasive plants typically have a relatively short residence time in their introduced ranges (decades or just a few centuries). Besides the time constraint, founder effects (reduction in population size and genetic diversity) may also limit the capacity of invasive plants to rapidly evolve local adaption. Thus, invasive plants may be less likely than native plants to evolve local adaptation. Interestingly, however, an expanding body of literature documents the existence of local adaptation in invasive plant species within their exotic ranges.
Here, we did a phylogenetically controlled meta-analysis to compare invasive and native plant species for differences in the frequency and magnitude of local adaptation. The meta-analysis was based on different experiments performed in various habitats including grasslands, steppes, deserts, forests, mountains, wetlands and dunes, and used a total of 134 plant species in 52 families. Forty seven of these species (in 24 families) are alien invaders in the region where the studies were undertaken, while the other 91 species (in 38 families) are native.
On average, local plants performed better than foreign plants, and invasive plant species expressed local adaptation just as frequently, and at least as strongly as that exhibited by native plant species. An analysis performed while taking into account different plant life-history traits showed that self-incompatible invasive plants exhibited significantly higher frequencies of local adaptation than native plants characterized by the same breeding system.
Synthesis. The present results support the suggestion that rapid evolution of local adaptation may enable invasive plant species to occupy a broad range of novel habitats.

针对外来入侵植物物种的生态影响所引发的担忧，促使学界产生了浓厚的研究兴趣，以期阐明这类植物能够广泛占据各类生境的内在机制。已有研究反复提出，对新生境的本地适应（local adaptation）快速演化，或许能帮助入侵植物广泛占据各类新型生境。然而，经典达尔文自然选择演化理论认为，该过程缓慢且渐进，往往需要数千年的时间。入侵植物在其入侵区域的定居时间通常相对较短（仅数十年至数百年）。除了时间限制之外，奠基者效应（founder effects，即种群规模与遗传多样性的降低）也可能限制入侵植物快速演化出本地适应的能力。因此，相较于本土植物，入侵植物演化出本地适应的可能性更低。但有趣的是，越来越多的文献报道了入侵植物在其外来分布区内存在本地适应现象。
本研究采用系统发育控制（phylogenetically controlled）的元分析（meta-analysis）方法，对比入侵植物与本土植物的本地适应发生频率及强度差异。本次元分析整合了在草地、温带草原、荒漠、森林、山地、湿地与沙丘等多种生境中开展的不同实验，共纳入52个科的134种植物。其中47个物种（隶属于24个科）为研究开展区域的外来入侵物种，剩余91个物种（隶属于38个科）为本土植物。
整体而言，本地植株的表现优于外来植株，且入侵植物的本地适应发生频率与本土植物相当，其本地适应的强度至少不低于本土植物。结合不同植物生活史性状（life-history traits）开展的分析显示，自交不亲和（self-incompatible）的入侵植物的本地适应发生频率，显著高于具有相同繁育系统（breeding system）的本土植物。
综合与结论。本研究结果支持这一假说：本地适应的快速演化，可帮助入侵植物广泛占据各类新型生境。