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Isolated wetlands of the southeastern United States: abundance and expected condition
Citation:
LANE, C. R., E. D'Amico, AND B. C. AUTREY. Isolated wetlands of the southeastern United States: abundance and expected condition. WETLANDS. The Society of Wetland Scientists, McLean, VA, 32(4):753-767, (2012).
Impact/Purpose:
There are three main objectives of the proposed research in isolated wetlands: 1) isolated wetland characterization and conditional assessment; 2) isolated wetlands and landscape nutrient dynamics, including annual and seasonal variation in soil and water parameters; and 3) accuracy assessment and extent determination of isolated wetlands.
Description:
In the wake of two U.S. Supreme Court decisions that severely curtailed federal protection for isolated wetlands in the U.S. (i.e., those completely surrounded by uplands), the true extent of the wetlands impacted, and thus, the implications of the decisions, is unknown. Best professional judgment from almost a decade ago estimated <20% of the contiguous U.S. wetland area to be isolated. In this study we used the National Wetlands Inventory and a buffering process to mask where potential wetlands in an eight state region of the southeastern and mid-Atlantic U.S. intersected stream, river and lake buffers and identified 813,163 putative isolated wetlands covering 1,185,022.6 ha. Isolated wetlands ranged from 3.6 - 11/0% of the total freshwater habitat, were densely occurring and typically small. Approximately 50% of the extant isolated wetlands were found to be in "reference" or good condition, as determined by examining the land use surrounding each wetland and applying a landscape-level measure of anthropogenic disturbance, the Landscape Development Intensity (LDI) index. Based on this study, >3% of the wetland area in the conterminous U.S. are potential isolated wetlands occurring in this eight-state study area.
