Community Persistence and the Pattern of Community Variability Over Time: A Test Using Fossil Assemblages From Four Marine Transgressions in the Breathitt Formation......

这项研究将使用肯塔基州东部四次单独的海洋淹没的化石记录来测试群落在10 - 10年时间尺度上的持久性。每次海洋淹没都导致底栖生物栖息地的建立，这些栖息地被相同或相似的海洋无脊椎动物占据，并被保存为化石页岩层。四个海洋单元将在多个地点进行采样和复制，以获得每个样本的完整化石物种丰度。每个样品的岩性和微动物特征将用于确定在可比生境中形成的样品。将对来自可比生境的样本进行统计比较。重复样本将提供对抽样造成的变异的估计，这将构成判断海洋单元内各地点之间变异重要性的基础。比较一个海洋单元内多个地点的统计测试将显示每次海洋淹没期间存在的群落结构变化的地理格局。在每个海洋单元中所看到的物种丰度的变化，反过来将为判断相同的群落结构是否在重大破坏后重新组合并在部分或全部海洋淹没中持续存在提供基础。该项目旨在严格测试(a)化石组合是否在更高度结构化的意义上代表群落，而不仅仅是组成物种的巧合共存；(b)化石群落（以来自特定栖息地的化石组合为代表）是否在重大破坏后持续存在。

This study will use the fossil record of four separate marine inundations of eastern Kentucky to test for community persistence on a time scale of 10 - 10 years. Each marine inundation resulted in the establishment of benthic habitats that were colonized by the same or similar species of marine invertebrates and preserved as layers of fossiliferous shale. Four marine units will be sampled with replication at multiple locations to obtain complete fossil species abundances for each sample. The lithological and microfaunal characteristics of each sample will be used to determine which samples formed in comparable habitats. Samples from comparable habitats will be statistically compared. Replicate samples will provide an estimate of variation due to sampling that will form the basis for judging the significance of variation between localities within a marine unit. Statistical tests comparing multiple localities within a marine unit will demonstrate the geographic pattern of variation in community structure that existed during each marine inundation. The variation in species abundances seen within each marine unit will, in turn, provide a basis for judging whether the same community structure was reassembled after major disruptions and persisted through some or all of the marine inundations. The project is designed to rigorously test (a) whether fossil assemblages represent communities in a more highly structured sense than just the coincidental co-occurrence of component species, and (b) whether fossil communities (as represented by fossil assemblages from particular habitats) persist through time despite major disruptions.