Impacts of Migration on Pond Food Web Structure: Insights From Metacommunity Biology and Implications for Multi-Scale Diversity

生态扩散对群落过程的重要性得到了广泛的认识。然而，无论是迁徙对物种丰富的群落的影响的大小，还是扩散和当地社区过程的相互作用，都没有得到很好的理解。也许探讨移徙到社区和区域的后果最合适的框架是元社区，因为它承认影响社区动态的多尺度过程。元群落生物学解决群落间扩散的影响，并在空间明确的背景下将局部过程与区域过程联系起来。新出现的集合群落理论表明，分散率可以显著影响当地和地区的物种丰富度和生态系统功能，但使用简单化的食物网模型来做到这一点。相比之下，经验的集合群落调查采用了多个营养水平，但未能成功地分离出与迁徙相互作用的局部机制。我们的研究解决了这两种方法之间的明显脱节，并采用多营养和机械的方法来评估扩散和社区水平的时空异质性对池塘食物网的影响。结果表明，扩散速率改变了局部和区域尺度上的物种丰富度，并影响营养结构。拟议的工作扩展了这些概念，并将生活史权衡理论纳入到元社区框架中。通过综合机械论、元群落和权衡理论，这项研究可能为物种的发生和共存提供新的见解。此外，随着支离破碎的景观变得越来越普遍，以及当地和区域生物群的修改，这项研究对保护具有很强的意义。归根结底，重要的是隔离和确定当地和区域物种丰富的驱动因素，以便在全球范围内保持生物完整性。

The importance of ecological dispersal on community processes is widely recognized. However, neither the magnitude of migration effects on species-rich communities, nor the interplay of dispersal and local community processes, is well understood. Perhaps the most appropriate framework for exploring the consequences of migration to the community and region is the metacommunity, as it acknowledges multi-scale processes influencing community dynamics. Metacommunity biology addresses the impacts of inter-community dispersal, and links local to regional processes in a spatially explicit context. Emergent metacommunity theory indicates that dispersal rate can dramatically affect local and regional species richness, and ecosystem functioning, yet uses simplistic food web models to do so. In contrast, empirical metacommunity investigations employ multiple trophic levels but unsuccessfully isolate local mechanisms interacting with migration. Our research addresses the apparent disconnect between the two methods, and takes a multi-trophic and mechanistic approach to evaluating the effects of dispersal and community-level spatio-temporal heterogeneity on pond food webs. Results indicate that dispersal rate alters species richness at local and regional scales, and affects trophic structure. The proposed work extends these concepts and incorporates life-history trade-off theory into a metacommunity framework. By synthesizing mechanistic, metacommunity, and trade-off theory the research may provide novel insight into species incidence and coexistence. Further, the research has strong implications for conservation as fragmented landscapes become increasingly prevalent, and local and regional biotas modified. Ultimately, it is important to isolate and identify drivers of local and regional species richness in order to maintain biotic integrity at the global scale.