Large herbivores trigger spatiotemporal changes in forest plant diversity

Large herbivores can exert top-down control on terrestrial plant communities, but the magnitude, direction, and scale-dependency of their impacts remain equivocal, especially in temperate and boreal forests, where multiple disturbances often interact. Using a unique, long-term and replicated landscape experiment, we assessed the influence of a high density of white-tailed deer (Odocoileus virginianus) on the spatiotemporal dynamics of diversity, composition, and successional trajectories of understorey plant assemblages in recently logged boreal forests. This experiment provided a rare opportunity to test whether deer herbivory represents a direct filter on plant communities or if it mainly acts to suppress dominant plants which, in turn, release other plant species from strong negative plant-plant interactions. These two hypotheses make different predictions about changes in community composition, alpha and beta diversity in different vegetation layers and at different spatial scales. ...

大型草食动物可对陆地植物群落施加下行调控效应，但其影响的强度、方向及尺度依赖性仍存在争议，尤其是在多重干扰时常相互作用的温带与北方森林中。本研究依托一项独特的长期重复景观实验，探究了高密度白尾鹿（Odocoileus virginianus）对近期采伐后的北方森林林下植物群落的多样性、组成及演替轨迹的时空动态影响。该实验为我们提供了难得的研究契机，用以检验鹿类植食作用究竟是对植物群落构成直接过滤，还是主要通过抑制优势植物，进而使其他植物物种摆脱强烈的种间负相互作用。这两种假说针对不同植被层、不同空间尺度下的群落组成、α多样性与β多样性变化做出了不同的预测……