Oldfather Meagan F, Van Den Elzen Courtney L, Heffernan Patrick M, Emery Nancy C
Department of Ecology and Evolutionary Biology, University of Colorado Boulder, CO 80309, USA.
Am J Bot. 2021 Sep;108(9):1584-1594. doi: 10.1002/ajb2.1739. Epub 2021 Sep 29.
Dispersal-the movement of an individual from the site of birth to a different site for reproduction-is an ecological and evolutionary driver of species ranges that shapes patterns of colonization, connectivity, gene flow, and adaptation. In plants, the traits that influence dispersal often vary within and among species, are heritable, and evolve in response to the fitness consequences of moving through heterogeneous landscapes. Spatial and temporal variation in the quality and quantity of habitat are important sources of selection on dispersal strategies across species ranges. While recent reviews have evaluated the interactions between spatial variation in habitat and dispersal dynamics, the extent to which geographic variation in temporal variability can also shape range-wide patterns in dispersal traits has not been synthesized. In this paper, we summarize key predictions from metapopulation models that evaluate how dispersal evolves in response to spatial and temporal habitat variability. Next, we compile empirical data that quantify temporal variability in plant demography and patterns of dispersal trait variation across species ranges to evaluate the hypothesis that higher temporal variability favors increased dispersal at plant range limits. We found some suggestive evidence supporting this hypothesis while more generally identifying a major gap in empirical work evaluating plant metapopulation dynamics across species ranges and geographic variation in dispersal traits. To address this gap, we propose several future research directions that would advance our understanding of the interplay between spatiotemporal variability and dispersal trait variation in shaping the dynamics of current and future species ranges.
扩散——个体从出生地点移动到不同地点进行繁殖——是物种分布范围的一种生态和进化驱动因素，它塑造了物种的定殖、连通性、基因流动和适应模式。在植物中，影响扩散的性状在种内和种间通常存在差异，具有遗传性，并会随着在异质景观中移动所带来的适合度后果而进化。栖息地质量和数量的时空变化是影响物种分布范围内扩散策略选择的重要因素。虽然近期的综述评估了栖息地空间变化与扩散动态之间的相互作用，但尚未综合探讨时间变异性的地理差异在多大程度上也能塑造扩散性状的全范围模式。在本文中，我们总结了集合种群模型的关键预测，这些模型评估了扩散如何响应空间和时间上的栖息地变异性而进化。接下来，我们收集实证数据，量化植物种群统计学中的时间变异性以及物种分布范围内扩散性状变异的模式，以评估在植物分布范围边缘更高的时间变异性有利于增加扩散这一假设。我们发现了一些支持该假设的暗示性证据，同时更普遍地指出了在评估跨物种分布范围的植物集合种群动态和扩散性状地理变异的实证研究中存在的一个重大空白。为了填补这一空白，我们提出了几个未来的研究方向，这些方向将推动我们对时空变异性与扩散性状变异之间的相互作用在塑造当前和未来物种分布范围动态方面的理解。
