Patterns of Ecological Performance and Aquatic Insect Diversity in High Quality Protected Area Networks

Protected areas are at the heart of plans for biodiversity conservation. Networks of protected areas may provide opportunities to protect conservation targets or objectives not attainable for single parcels of land. The landscape of potential decisions available to conservation planners is constrained by uncertainty about the form of future climate states. New methods are available that can provide objective assessments of the direction and magnitude of shifts in climate regimes that are not first filtered through theoretical responses of biodiversity. Successful predictions of where, in protected area networks, climates are most likely to change, or most likely to remain in situ, would be valuable information for planners and conservationists. As climate change influences the potential distribution of plants and animals on the landscape, the realized effects of these changes will be determined in part by the capacity for dispersal among habitats, including protected areas. Understanding the processes that generate species diversity first requires describing the patterns; for aquatic insect species in the southeastern United States these patterns are not fully known. I describe the composition of aquatic insect assemblages in national parks as a function of the size and distance between parks, composition of regional source pools, position along environmental gradients and assessments of the perceived imperilment of individual aquatic insect species. I compare turnover among habitats and parks to test hypotheses about the partitioning of species diversity among sites, including general comparisons of headwater and mid-order streams and more explicit hypotheses on the structure of turnover along spatial and environmental gradients. Benthic data on family or genera level identifications cannot adequately test these hypotheses because the lack of taxonomic resolution obscures the sources of compositional dissimilarity between sites.