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

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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.