The exchange of water, sediment, carbon, and nutrients between terrestrial and aquatic ecosystems is regulated by riparian zones. More than 73 km of upland streams exist in the 2185 ha of forest at Coweeta Hydrologic Laboratory. Therefore, riparian zones constitute a large proportion of the landscape. Most riparian zones in these forested areas are dominated by Rhododendron maximum, an evergreen shrub. This keystone species (i.e., it has a greater role than its coverage would suggest) is slow growing, but has increased in coverage since fire suppression began in the 1920s. To determine the effect of Rhododendron in riparian areas, soilwater, groundwater, nutrients, and litter fluxes are being quantified in areas where Rhododendron has been  removed, and compared to untreated control areas during a multi-year study.

       Socioeconomic research in our southern Appalachian regionalization study area has quantified both the past (1950s) and current land use patterns for selected study areas. These Geographic Information System (GIS) layers are the bases for both anthropological and economic studies to determine the causes and consequences of observed land use patterns and changes over time. In addition, our socioeconomic studies are predicting land use patterns for the year 2030, which will provide likely future scenarios depicting the consequences of present patterns of population growth and land use change. Current trends indicate that the largest land use shift is from marginal agricultural land back to successional forested areas, but increased home construction is causing the forested areas to become more fragmented.

       Regional aquatic studies in the greater 56,000 km 2 southern Appalachian study area quantify the impact that historical and current land use has on the productivity and diversity of stream fauna. Even though terrestrial vegetation may have recovered from disturbance in most of a watershed, stream fauna reflect past disturbance conditions from as many as 50 years earlier, suggesting that recovery time may be greater for stream than terrestrial ecosystems.

      Terrestrial studies are focusing on the impact of disturbance on both small mammal and herbaceous diversity. In addition, we are  building a carbon cycling model, based on measured pools and fluxes of carbon across land use types. This model will allow carbon cycling predictions to be made for the southern Appalachian region based on current and predicted land use patterns derived from socioeconomic research.