Data from: Evolution mediates the effects of apex predation on aquatic food webs

Ecological and evolutionary mechanisms are increasingly thought to shape local community dynamics. Here, I evaluate if the local adaptation of a meso-predator to an apex predator alters local food webs. The marbled salamander (Ambystoma opacum) is an apex predator that consumes both the spotted salamander (Ambystoma maculatum) and shared zooplankton prey. Common garden experiments reveal that spotted salamander populations which co-occur with marbled salamanders forage more intensely than those that face other predator species. These foraging differences, in turn, alter the diversity, abundance and composition of zooplankton communities in common garden experiments and natural ponds. Locally adapted spotted salamanders exacerbate prey biomass declines associated with apex predation, but dampen the top-down effects of apex predation on prey diversity. Countergradient selection on foraging explains why locally adapted spotted salamanders exacerbate prey biomass declines. The two salamander species prefer different prey species, which explains why adapted spotted salamanders buffer changes in prey composition owing to apex predation. Results suggest that local adaptation can strongly mediate effects from apex predation on local food webs. Community ecologists might often need to consider the evolutionary history of populations to understand local diversity patterns, food web dynamics, resource gradients and their responses to disturbance.生态与进化机制正日益被学界认为是调控局域群落动态的核心驱动力。本研究旨在探究：中捕食者（meso-predator）对顶级捕食者（apex predator）的局域适应，是否会改变局域食物网结构。云斑钝口螈（marbled salamander, Ambystoma opacum）是一种顶级捕食者（apex predator），其捕食对象涵盖斑点钝口螈（spotted salamander, Ambystoma maculatum）以及共享的浮游动物（zooplankton）猎物。共同花园实验（common garden experiment）结果显示，与云斑钝口螈同域共存的斑点钝口螈种群，其觅食强度显著高于遭遇其他捕食者的种群。这些觅食行为差异，进而会改变共同花园实验与自然池塘中浮游动物群落的多样性、丰度与组成结构。经局域适应的斑点钝口螈会加剧顶级捕食者引发的猎物生物量下降，但却会削弱顶级捕食者对猎物多样性的下行控制效应（top-down effect）。觅食行为相关的反梯度选择（countergradient selection），可以解释经局域适应的斑点钝口螈为何会加剧猎物生物量的下降。两种钝口螈偏好不同的猎物类群，这一特征解释了经局域适应的斑点钝口螈为何能够缓冲顶级捕食者引发的猎物组成变化。研究结果表明，局域适应能够显著调控顶级捕食者对当地食物网的影响效应。群落生态学家通常需要考量种群的进化历史，才能充分理解局域多样性格局、食物网动态、资源梯度及其对干扰的响应规律。