Data from: Impacts of dispersal on rapid adaptation and dynamic stability of Daphnia in fluctuating environments

Prior ecological research has shown that spatial processes can enhance the temporal stability of populations in fluctuating environments. Less explored is the effect of dispersal on rapid adaptation and its concomitant impact on population dynamics. For asexually reproducing populations, theory predicts that dispersal in fluctuating environments can facilitate asynchrony among clones and enhance stability by reducing temporal variability of total population abundance. This effect is predicted when clones exhibit heritable variation in environmental optima and when fluctuations occur asynchronously among patches. We tested this in the field using artificial ponds and metapopulations composed of a diverse assemblage of <i>Daphnia pulex</i> clones. We directly manipulated dispersal presence/absence and environmental fluctuations in the form of nutrient pulses. Consistent with predictions, dispersal enhanced temporal asynchrony among clones in the presence of nutrient pulses; this in turn stabilized population dynamics. This effect only emerged when patches experienced spatially asynchronous nutrient pulses (dispersal had no effect when patches were synchronously pulsed). Clonal asynchrony was driven by strong positive selection for a single clone that exhibited a performance advantage under conditions of low resource availability. Our work highlights the importance of dispersal as a driver of eco-evolutionary dynamics and population stability in variable environments.既往生态学研究表明，在波动环境中，空间过程可提升种群的时间稳定性。目前针对扩散对快速适应及其伴随的种群动态影响的研究仍较为匮乏。针对无性繁殖种群，理论预测在波动环境中，扩散可促进克隆（clone）间的异步性，并通过降低种群总丰度的时间变异性来提升稳定性。该效应的预测前提为：克隆在环境最适条件上存在可遗传变异，且各斑块间的环境波动异步发生。我们采用人工池塘以及由多样的蚤状溞（Daphnia pulex）克隆群落组成的集合种群（metapopulation），在野外开展了相关验证实验。我们直接操控了扩散的有无，并以营养脉冲（nutrient pulses）的形式调控环境波动。与理论预测一致，在存在营养脉冲的情况下，扩散提升了克隆间的时间异步性，进而稳定了种群动态。该效应仅在斑块间营养脉冲空间异步发生时显现——当斑块间营养脉冲同步进行时，扩散未产生任何影响。克隆间的异步性源于对单个克隆的强烈正向选择：该克隆在低资源可获得性条件下表现出适应优势。本研究凸显了扩散作为可变环境中生态-进化动态与种群稳定性驱动因子的重要性。