Recovery of streams from agriculture

Matthew Eric McTammany

E. F. Benfield, Chairman

ABSTRACT

Agriculture has affected streams in the eastern United States for over 250 years. Socioeconomic changes in the southern Appalachian Mountains have led to widespread abandonment of agricultural fields and subsequent reforestation. We have been investigating the recovery of stream ecosystems from agriculture in the southern Appalachians by locating streams whose watersheds are currently forested but were historically (circa 1950) agricultural. Sites were selected by categorizing watersheds (500-1000 ha) into one of six classes representing a gradient of current and historical agriculture. Five sites from across the southern Appalachians (NC and VA) were selected in each category (30 streams total). We have been assessing degree of and recovery from agricultural impact on many different aspects of streams including: geomorphology, water chemistry, biological structure (algae, benthic macroinvertebrates, and fish), and ecosystem function (wood breakdown and metabolism). Preliminary results indicate that historical agriculture has a continued effect on stream properties despite decades of watershed reforestation. Continued research should enable us to model recovery patterns of agriculturally impacted streams.