Jerri Phillips, Effect Of Riparian Land Use On The Biotic Integrity Of Fish Assemblages In Black Creek, Chattanooga, Tennessee
Faculty Chair: Dr. Mark Schorr
Black Creek is a third-order Ridge and Valley stream (Tennessee River drainage) in Chattanooga, Tennessee. Most of Black Creek's watershed is forested (ca. 71% in 1991). However, increasing urban development, particularly along the riparian landscapes, could impact the stream's ecological health. I assessed fish assemblages (biotic integrity), water quality, instream habitat, and riparian land-use features at eight sites in Black Creek, May-June 2000. Water quality conditions (temperature, dissolved oxygen, pH, conductivity) were favorable for stream fishes, but some level of habitat degradation (bank erosion, sedimentation, loss of riparian vegetation) was observed at all sites. Electrofishing samples yielded a total of 29 species and 9,178 fish. Index of biotic integrity (IBI) scores ranged from 30 to 42, corresponding to IBI ratings of "poor" to "fair," respectively, at the individual sites. The IBI score was negatively correlated with sediment depth in the stream (r = -0.727, P = 0.041) and the percentage of urban land use in the riparian zone (r = -0.739, P = 0.036). Urban land use was negatively correlated with the dissolved oxygen concentration (r = -0.888, P = 0.003). Findings from this study document the negative effect of urban land use on biotic integrity in a Ridge and Valley stream, and provide baseline data for community planning, bioassessment, and mitigation projects.