Data from: How much do phenotypic plasticity and local genetic variation contribute to phenotypic divergences along environmental gradients in widespread invasive plants? A meta-analysis

For introduced species that have spread across a wide distributional range, phenotypic plasticity (PLA) has often been proposed as an important contributor to invasion success, because it increases the survival rate during initial colonization. In contrast, local genetic variation (LOC) has also been proposed to be important, because it could allow invaders to evolve high performance in a new habitat. While evolutionary ecologists have long been interested in understanding genetic mechanisms that allow rapid colonization and spread of species, until recently experimental tests of these concepts have been limited. As a step towards generalization in our understanding of the importance of PLA and LOC, we review the current state of the literature on this topic using meta-analysis. Here, we focused on three fundamental questions: (i) Which strategy, PLA or LOC, better explains the phenotypic divergences during invader range expansion across different environmental gradients? (ii) Which species characteristics correlate with the occurrence of these different phenomena? And (iii) Does the detection of PLA versus LOC depend on the trait studied? Using meta-analysis we found that plasticity explained a higher proportion of phenotypic variation regardless of the environmental gradients studied or plant growth forms. PLA predominated in clonal, self-compatible and perennial species, while LOC predominated in annual species. The patterns were trait-dependent: LOC was significantly more important than PLA in phenology, while opposite patterns were found in fecundity and biomass allocation. The frequent simultaneous detection of PLA and genotypic variation in PLA among invasive populations suggested that PLA might benefit from LOC to some extent. Our results also indicate that the contribution of plasticity to the competitive advantages of invasive plants may be more informative than the level of plasticity itself.

针对已实现大范围扩散的外来入侵物种，表型可塑性（phenotypic plasticity, PLA）常被视作其入侵成功的关键驱动因子，因其可提升物种在初始定殖阶段的存活率。与之相对，本地遗传变异（local genetic variation, LOC）同样被认为具有重要作用：它可使入侵物种在新栖息地中演化出优异的适应性能。长期以来，进化生态学家一直致力于阐明支撑物种快速定殖与扩散的遗传机制，但直至近期，针对这两类假说的实验验证仍较为有限。为深化我们对表型可塑性与本地遗传变异重要性的普适性认知，本研究采用元分析（meta-analysis）对该领域的现有文献开展系统综述。我们聚焦于三个核心问题：（i）在不同环境梯度下的入侵物种分布范围扩张过程中，表型可塑性与本地遗传变异哪一种更能解释表型分化现象？（ii）哪些物种特征与这两类现象的发生存在关联？（iii）表型可塑性与本地遗传变异的检出是否取决于所研究的性状？通过元分析我们发现，无论所研究的环境梯度或植物生长型如何，表型可塑性均能解释更高比例的表型变异。表型可塑性在无性系、自交亲和以及多年生植物中占主导地位，而本地遗传变异则在一年生植物中更为普遍。上述模式存在显著的性状依赖性：本地遗传变异在物候性状中的重要性显著高于表型可塑性，而在繁殖力与生物量分配性状中则呈现相反的结果。此外，我们频繁在入侵种群中同时检测到表型可塑性以及入侵种群间表型可塑性的遗传变异，这表明表型可塑性或许可在一定程度上借助本地遗传变异获得收益。我们的研究结果还表明，相较于表型可塑性本身的水平，其对入侵植物竞争优势的贡献更具研究价值。