Does primary productivity modulate the indirect effects of large herbivores? A global meta-analysis

1. Indirect effects of large mammalian herbivores (LMH), while much less studied than those of apex predators, are increasingly recognized to exert powerful influences on communities and ecosystems. The strength of these effects is spatiotemporally variable, and several sets of authors have suggested that they are governed in part by primary productivity. However, prior theoretical and field studies have generated conflicting results and predictions, underscoring the need for a synthetic global analysis. 2. We conducted a meta-analysis of the direction and magnitude of large mammalian herbivore-initiated indirect interactions using 67 published studies comprising 456 individual responses. We georeferenced 41 of these studies (comprising 253 responses from 33 locations on 5 continents) to a satellite-derived map of primary productivity. Because predator assemblages might also influence the impact of large herbivores, we conducted a similar analysis using a global map of large-carnivore ...1. 大型哺乳动物草食动物（large mammalian herbivores, LMH）的间接效应，尽管其研究程度远不及顶级捕食者（apex predators），但如今日益被学界认识到对群落与生态系统具有强大调控作用。这类效应的强度具有时空异质性，已有多组学者提出其在一定程度上受初级生产力（primary productivity）调控。然而，此前的理论与野外研究得出了相互矛盾的结果与预测，这凸显了开展综合性全球分析的必要性。 2. 本研究针对大型哺乳动物草食动物介导的间接相互作用的方向与强度开展了元分析（meta-analysis），共纳入67项已发表研究，涵盖456个独立响应变量。我们将其中41项研究（包含来自5大洲33个采样点的253个响应变量）的空间坐标匹配至卫星遥感获取的初级生产力分布图。考虑到捕食者类群也可能影响大型草食动物的生态效应，我们借助全球大型食肉动物...