The Rubenstein School of Environment and Natural Resources, The University of Vermont, Burlington, VT, USA.
USDA Forest Service, Northern Research Station, Burlington, VT, USA.
Ecol Lett. 2018 May;21(5):745-759. doi: 10.1111/ele.12934. Epub 2018 Mar 8.
High competitive ability has often been invoked as a key determinant of invasion success and ecological impacts of non-native plants. Yet our understanding of the strategies that non-natives use to gain competitive dominance remains limited. Particularly, it remains unknown whether the two non-mutually exclusive competitive strategies, neighbour suppression and neighbour tolerance, are equally important for the competitive advantage of non-native plants. Here, we analyse data from 192 peer-reviewed studies on pairwise plant competition within a Bayesian multilevel meta-analytic framework and show that non-native plants outperform their native counterparts due to high tolerance of competition, as opposed to strong suppressive ability. Competitive tolerance ability of non-native plants was driven by neighbour's origin and was expressed in response to a heterospecific native but not heterospecific non-native neighbour. In contrast to natives, non-native species were not more suppressed by hetero- vs. conspecific neighbours, which was partially due to higher intensity of intraspecific competition among non-natives. Heterogeneity in the data was primarily associated with methodological differences among studies and not with phylogenetic relatedness among species. Altogether, our synthesis demonstrates that non-native plants are competitively distinct from native plants and challenges the common notion that neighbour suppression is the primary strategy for plant invasion success.
高竞争力常被认为是决定外来植物入侵成功和生态影响的关键因素。然而，我们对外来植物获得竞争优势所采用的策略的理解仍然有限。特别是，两种非互斥的竞争策略，即邻体抑制和邻体耐受，对于外来植物的竞争优势是否同样重要，目前仍不清楚。在这里，我们在贝叶斯多层次元分析框架内，分析了 192 篇关于植物种间竞争的同行评审研究的数据，结果表明，外来植物由于具有较强的竞争耐受能力，而不是较强的抑制能力，从而优于其本地对应物。外来植物的竞争耐受能力取决于邻体的起源，并对外来同种但不是外来异种邻体的竞争做出响应。与本地种不同，外来种不会因异种与同种邻体的竞争而受到更大的抑制，这在一定程度上是由于外来种之间的种内竞争强度较高。数据中的异质性主要与研究之间的方法差异有关，而与物种之间的系统发育关系无关。总的来说，我们的综合研究表明，外来植物与本地植物在竞争上有明显的区别，这挑战了邻体抑制是植物入侵成功的主要策略的常见观点。
