Lakeshore and littoral physical habitat structure in a national lakes assessment

AbstractNear-shore physical habitat is crucial for supporting biota and ecological processes in lakes. We used data from a statistical sample of 1101 lakes and reservoirs from the 2007 US Environmental Protection Agency National Lakes Assessment (NLA) to develop 4 indices of physical habitat condition: (1) Lakeshore Anthropogenic Disturbance, (2) Riparian Vegetation Cover Complexity, (3) Littoral Cover Complexity, and (4) Littoral–Riparian Habitat Complexity. We compared lake index values with distributions from least-disturbed lakes. Our results form the first US national assessment of lake physical habitat, inferring the condition (with known confidence) of the 49,500 lakes and reservoirs in the conterminous United States with surface areas >4 ha and depths >1 m. Among the physical and chemical characteristics examined by the NLA, near-shore physical habitat was the most extensively altered relative to least-disturbed condition. Riparian Vegetation Cover Complexity was good in 46% (±3%), fair in 18% (±2...