Patterns of Species Loss in Forest Understory Plant Communities

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9974041WallerPlant communities in many areas are losing species at unprecedented rates. While the mechanisms responsible for these losses vary and are often difficult to identify, there appear to be general trends governing which species are most vulnerable to being lost. Rare and localized species are usually at greater risk of local extirpation, and patterns of species loss often result in most habitat patches containing common and widespread species. Habitat fragmentation, shifts in historic disturbance regimes, the invasion of exotic species, and herbivory by elevated populations of white-tailed deer all appear to be proximate mechanisms driving these losses in various habitats. This study will investigate patterns of community composition and species loss in understory plant communities in forests of northern Wisconsin and Michigan's upper peninsula as a vehicle to understand the nature, extent, and mechanisms of these losses. Data will be collected from 120+ sites distributed across six community/soil types in this region to address several ecological questions. To test the predictability of species loss, nested species compositions will be analyzed. To assess historic losses, contemporary species presence data will be compared to historical data collected by John T. Curtis and colleagues for these forests. Patterns of historical decline will be compared to current patterns of nestedness among habitat patches to assess how well current patterns of nestedness reflect historical processes. Hierarchical spatial sampling will allow us to construct species-area curves for comparisons across community and soil types. These results will improve our understanding of natural community dynamics, historical shifts in these communities, and current mechanisms of species loss.