Data from: Rapid evolution leads to differential population dynamics and top-down control in resurrected Daphnia populations

There is growing evidence of rapid genetic adaptation of natural populations to environmental change, opening the perspective that evolutionary trait change may subsequently impact ecological processes such as population dynamics, community composition and ecosystem functioning. To study such eco-evolutionary feedbacks in natural populations, however, requires samples across time. Here we capitalize on a resurrection ecology study that documented rapid and adaptive evolution in a natural population of the water flea Daphnia magna in response to strong changes in predation pressure by fish, and carry out a follow-up mesocosm experiment to test whether the observed genetic changes influence population dynamics and top-down control of phytoplankton. We inoculated populations of the water flea D. magna derived from three time periods of the same natural population known to have genetically adapted to changes in predation pressure in replicate mesocosms, and monitored both Daphnia population densities and phytoplankton biomass in the presence and absence of fish. Our results revealed differences in population dynamics and top-down control of algae between mesocosms harboring populations from the time period before, during and after a peak in fish predation pressure caused by human fish stocking. The differences, however, deviated from our a priori expectations. An S-map approach on time series revealed that the interactions between adults and juveniles strongly impacted the dynamics of populations and their top-down control on algae in the mesocosms, and that the strength of these interactions was modulated by rapid evolution as it occurred in nature. Our study provides an example of an evolutionary response that fundamentally alters the processes structuring population dynamics and impacts ecosystem features.

越来越多的证据表明，自然种群正快速发生遗传适应以响应环境变化，这为探究演化性状改变后续如何影响种群动态、群落组成及生态系统功能等生态过程提供了研究视角。然而，若要在自然种群中研究这类生态-演化反馈过程，则需要获取不同时间节点的样本。本研究依托一项复活生态学（resurrection ecology）研究——该研究记录了大型溞（Daphnia magna）自然种群在应对鱼类捕食压力显著变化时发生的快速适应性演化——并开展了后续中型实验生态系统（mesocosm）实验，以验证观测到的遗传改变是否会影响种群动态以及浮游植物的下行控制（top-down control）效应。我们将来自同一自然种群三个不同时间节点的大型溞（D. magna）种群接种至重复设置的中型实验生态系统中，这些种群已知已通过遗传适应应对了捕食压力变化；同时在有鱼和无鱼的条件下，分别监测大型溞的种群密度与浮游植物生物量。研究结果显示，接种了来自人类鱼类放养导致的鱼类捕食压力峰值前、峰值期及峰值后三个时间节点种群的中型实验生态系统之间，其种群动态与藻类下行控制效应均存在差异。但这些差异与我们的先验预期并不一致。通过对时间序列采用S-map方法分析后发现，中型实验生态系统中大型溞成体与幼体间的相互作用强烈影响种群动态及其对藻类的下行控制效应，且这类相互作用的强度受到野外自然发生的快速演化的调控。本研究提供了一个演化响应的实例——该演化响应从根本上改变了塑造种群动态的过程，并对生态系统特征产生影响。