David S. Leigh

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We tested the hypothesis that urbanization alters stream sediment regimes and homogenizes fish assemblages in 30 sub-basins of the Etowah River. Sediment variables included average particle size (mean phi) of the stream bed, percent fines (<2 mm) in riffles, and baseflow turbidity (NTU). Homogenization was quantified as ratios of endemic to cosmopolitan(More)
Jackson R. Webster, Ernest F. Benfield, Kristen K. Cecala, John F. Chamblee, Carolyn A. Dehring, Ted Gragson, Jeffrey H. Cymerman, C. Rhett Jackson, Jennifer D. Knoepp, David S. Leigh, John C. Maerz, Catherine Pringle and H. Maurice Valett 1Department of Biological Sciences, Virginia Tech University, Blacksburg, USA 2Warnell School of Forestry and Natural(More)
Morphological and sedimentological responses of streams to basin-scale impact have been well documented for intensively agricultural or urban areas. Sensitivity thresholds of streams to modest levels of disturbance, however, are not well understood. This study addresses the influence of forest conversion on streams of the southern Blue Ridge Mountains, a(More)
Holocene colluvial and alluvial stratigraphy and a radiocarbon chronology are presented for the valley of the lower three kilometers of Raven Fork, a mountain stream draining 194 km2 of high relief (1.3 km) terrain of the Southern Blue Ridge Mountains in western North Carolina, USA, which is in a region that lacks good chronological data. Lower hillslopes,(More)
For less-developed regions like the Blue Ridge Mountains, data are limited that link basin-scale land use with stream quality. Two pairs of lightly-impacted (90-100% forested) and moderately-impacted (70-80% forested) sub-basins of the upper Little Tennessee River basin in the southern Blue Ridge were identified for comparison. The pairs contain physically(More)
Small streams are understudied in the Southern Blue Ridge Mountains, yet they constitute a huge portion of the drainage network and are relevant with respect to human impact on the landscape and stream restoration efforts. Morphologies of 44 streams (0.01 to 20 km2 watersheds) from western North Carolina are characterized and couched in the context of(More)
Many studies have shown that streams degrade in response to urbanization in the watershed. These studies often are based on use of biotic and abiotic variables to measure stream health across a gradient of land cover/land use. The results of these studies can be applied to other urban systems, but often fail to provide a mechanistic understanding of the(More)
Changes in catchment land cover can impact stream ecosystems through altered hydrology and subsequent increases in sedimentation and nonpoint-source pollutants. These stressors can affect habitat suitability and water quality for aquatic invertebrates. We studied the impact of a range of physical and chemical stressors on aquatic insects, and tested whether(More)
We monitored water quality in the Chattooga River Watershed (NE Georgia, NW South Carolina, and SW North Carolina) to compare sediment TMDLs with observed water quality. A judicial consent decree required the EPA to establish TMDLs in one year. The EPA was unable to fully characterize the sediment budgets of these streams and consequently issued phased(More)
Parent materials greatly influence soil development and the distribution of soils on the southeastern US Coastal Plain. We examined the physical, chemical, and mineralogical properties of 11 pedons in a 1-ha plot on the Upper Coastal Plain of Georgia, USA. Uniformity of parent materials was assessed by sand grain size characteristics. The soils have sandy(More)