摘要：We studied fish assemblages within seven streams in the Ridge and Valley ecoregion near Chattanooga, Tennessee. These were all second- to fifth-order streams with small drainage areas (<23 km 2 ). Sites were characterized in terms of water quality, habitat, and fish assemblages. Relationships among these features and land use were examined at both the riparian and watershed scales. Forty fish species representing nine families were collected by electrofishing. Site-specific findings included the vulnerable flame chub (Hemitremia flammae) and a disjunct population of southern redbelly dace (Phoxinus elythrogaster). Species richness and diversity varied considerably among sites, and index of biotic integrity (IBI) ratings ranged tiom very poor to faidgood. Species diversity and IBI scores were negatively correlated with watershed urban land use and positively correlated with rocky substrate. Urbanized watersheds were characterized by sites with higher levels of sedimentation and conductivity. Reaches draining well-forested watersheds exhibited more rocky substrate, higher levels of dissolved oxygen, lower temperatures, and more diverse fish assemblages. Riparian forest cover was positively correlated with rocky substrate but not correlated with species diversity or biotic integrity.
