Dlugosch Katrina M, Cang F Alice, Barker Brittany S, Andonian Krikor, Swope Sarah M, Rieseberg Loren H
Department of Botany, University of British Columbia, BC V6T1Z4, Canada ; Department of Ecology and Evolutionary Biology, University of Arizona, AZ 85721, USA.
Department of Botany, University of British Columbia, BC V6T1Z4, Canada.
Nat Plants. 2015 Jun;1. doi: 10.1038/nplants.2015.66. Epub 2015 Jun 1.
Non-native plants are now a pervasive feature of ecosystems across the globe. One hypothesis for this pattern is that introduced species occupy open niches in recipient communities. If true, then non-native plants should often benefit from low competition for limiting resources that define niches. Many plants have evolved larger size after introduction, consistent with increased access to limiting resources. It has been difficult to test whether larger size reflects adaptation to exploit open resources, however, because vacant niches are generally challenging to identify in plants. Here we take advantage of a situation in which a highly invasive non-native plant, L. (yellow starthistle, hereafter 'YST'), occupies a well-described environmental niche, wherein water is a known limiting resource. We use a glasshouse common environment and climatic niche modeling to reveal that invading YST has evolved a higher-fitness life history at the expense of increased dependence on water. Critically, historical declines in resident competitors have made water more available for introduced plants, demonstrating how native biodiversity declines can open niches and create opportunities for introduced species to evolve increased resource use, a potentially widespread basis for introduction success and the evolution of invasive life histories.
非本土植物如今已成为全球生态系统中普遍存在的特征。对于这种模式的一种假设是，外来物种占据了受纳群落中的开放生态位。如果这一假设成立，那么非本土植物通常应受益于对界定生态位的有限资源的低竞争。许多植物在被引入后进化出了更大的体型，这与获取有限资源的增加相一致。然而，很难检验体型变大是否反映了对开放资源的利用适应性，因为在植物中通常很难确定空的生态位。在此，我们利用一种情况，即一种极具入侵性的非本土植物——黄矢车菊（以下简称“YST”）——占据了一个描述详尽的环境生态位，其中水是一种已知的有限资源。我们利用温室共同环境和气候生态位建模来揭示，入侵的YST进化出了更高适应性的生活史，但代价是对水的依赖性增加。至关重要的是，本地竞争者数量的历史下降使得水对引入植物来说更容易获取，这表明本地生物多样性的下降如何能够打开生态位，并为引入物种创造机会，使其进化出增加的资源利用能力，这可能是引入成功和入侵性生活史进化的一个普遍基础。
