Impact of Post-Wisconsinan Range Expansions on Community Structure of North American Endemic Earthworms

蚯蚓是大多数陆地生态系统的重要组成部分，对土壤结构和有机质分解过程具有重要影响。本提案利用一个重大的历史事件来关注生态学和生物地理学界面上的蚯蚓。冰期后向北扩散的差异被认为导致了蚯蚓群落结构从南到北的变化。一种分层方法被用来定义与景观特征、生殖生物学和生态因素有关的假设。现代气候对物种范围的限制、外来物种的竞争迁移和群落的相互作用结构被提出作为替代方案。在威斯康星冰川边缘的四个冰川避难所从南到北的样带和边缘以南的海拔样带上进行收集的项目将获得有关蚯蚓群落结构的数据，对扩散速率的长期估计，以及地理障碍对不同生态类别蚯蚓扩散的影响。提出了测量短期分散率和测试单代繁殖可能性的实验和替代模型。将建立一个生物地理和分类数据库。

Earthworms are important constituents of most terrestrial ecosystems and have a major influence on soil structure and organic matter decomposition processes. This proposal uses a major historical event to focus on earthworms at the interface of ecology and biogeography. Differential post-glacial northward dispersal is hypothesized to have caused variation in earthworm community structure from south to north. A hierarchical approach is used to define hypotheses relating dispersal to landscape features, reproductive biology, and ecological factors. Modern climatic limitation of species ranges, competitive displacement by exotic species, and interactive structuring of communities are proposed as alternatives. A program of collecting on four south to north transects from glacial refugia across Wisconsinan glacial margins and on elevational transects south of the margins will obtain data on earthworm community structures, long-term estimates of dispersal rates, and the influence of geographic barriers on dispersal of different ecological categories of earthworms. Experiments measuring short-term dispersal rates and testing the possibility of uniparental reproduction and alternative models are proposed. A biogeographic and taxonomic data base will be created.