Biological Assessment of Slope Wetlands on the Coastal Plain of South Carolina

Abstract

ABSTRACT Slope wetlands occur where groundwater emerges from hillsides to create shallow pools. These wetlands may be the initial point of contact between biota and emerging contaminated groundwater. We sampled several slope wetlands on the upper coastal plain of South Carolina that received contaminated groundwater and compared them to undisturbed slope wetlands. All of the wetlands supported a variety of insects, especially midge larvae and other Diptera, annelid worms, and aquatic beetles. Some supported large numbers of mites and copepods, and a few supported salamanders. Most taxa were tolerant of harsh conditions such as low dissolved oxygen and pH. Assemblage composition varied among wetlands due to differences in hydroperiod and likelihood of being flooded by nearby streams. Also important was the lack of shading in some disturbed wetlands, which permitted the growth of filamentous algae, sphagnum moss, and other plants. Few metrics commonly used for impact assessment differed between disturbed and undisturbed wetlands. High natural variability among slope wetlands and the natural tolerance of many slope wetland organisms may complicate the development of slope wetland multimetric indices, although such indices may be useful for identifying severely impacted wetlands.