Seed-dispersal networks respond differently to resource effects in open and forest habitats

While patterns in species diversity have been well studied across large-scale environmental gradients, little is known about how species' interaction networks change in response to abiotic and biotic factors across such gradients. Here we studied seed-dispersal networks on 50 study plots distributed over ten different habitat types on the southern slopes of Mt. Kilimanjaro, Tanzania, to disentangle the effects of climate, habitat structure, fruit diversity and fruit availability on different measures of interaction diversity. We used direct observations to record the interactions of frugivorous birds and mammals with fleshy-fruited plants and recorded climatic conditions, habitat structure, fruit diversity and availability. We found that Shannon interaction diversity (H) increased with fruit diversity and availability, whereas interaction evenness (EH) and network specialization (H2') responded differently to changes in fruit availability depending on habitat structure. The direction of...尽管物种多样性格局在大尺度环境梯度下已得到充分研究，但目前学界对物种互作网络如何响应此类梯度下的非生物与生物因子变化仍知之甚少。本研究以坦桑尼亚乞力马扎罗山南坡十种不同生境类型下的50个样地为研究对象，针对种子扩散网络展开调查，旨在厘清气候、生境结构、果实多样性及果实可获得性对不同互作多样性指标的影响。研究采用直接观测法记录食果鸟类与哺乳动物同肉质果植物的互作关系，并同步记录气候条件、生境结构、果实多样性及可获得性数据。研究结果显示，香农互作多样性（Shannon interaction diversity, H）随果实多样性与可获得性的提升而升高；而互作均匀度（interaction evenness, EH）与网络特化指数（network specialization, H2'）对果实可获得性变化的响应方向则依赖于生境结构。其响应方向……