High resistance towards herbivore-induced habitat change in a high arctic arthropod community

Mammal herbivores may exert strong impacts on plant communities, and are often key drivers of vegetation composition and diversity. We tested whether such mammal-induced changes to a high Arctic plant community are reflected in the structure of other trophic levels. Specifically, we tested whether substantial vegetation changes following the experimental exclusion of muskoxen (Ovibos moschatus) altered the composition of the arthropod community and the predator-prey interactions therein. Overall, we found no impact of muskox-exclusion on the arthropod community: the diversity and abundance of both arthropod predators (spiders) and of their prey were unaffected by muskox presence, and so was the qualitative and quantitative structure of predator-prey interactions. Hence, high Arctic arthropod communities seem highly resistant towards even large biotic changes in their habitat, which we attribute to the high connectance in the food web.

草食性哺乳动物可对植物群落施加显著影响，且通常是调控植被组成与多样性的关键驱动因子。本研究旨在探究：这类由哺乳动物介导的高北极地区植物群落变化，是否会在其他营养级的群落结构中得到体现。具体而言，我们检验了通过实验移除麝牛（Ovibos moschatus）后引发的显著植被变化，是否会改变节肢动物群落的组成及其内部的捕食者-猎物相互作用模式。整体而言，我们未发现麝牛移除实验对节肢动物群落产生显著影响：节肢动物捕食者（蜘蛛）及其猎物的多样性与丰度均未受麝牛存在与否的影响，捕食者-猎物相互作用的定性与定量结构亦未发生改变。由此可见，高北极地区的节肢动物群落即便面对栖息地内的大型生物扰动，亦表现出极强的抗性；我们将这一现象归因于该区域食物网的高连接度。