摘要：Effects of bridge and culvert construction or replacement were studied on 41 streams in Tennessee. One 100-m stream reach above and two 100-m reaches below were sampled at each bridge or culvert with a 50-m buffer zone separating each reach. Fish communities were sampled bi-annually for two years following single pass depletion techniques using a backpack electrofishing unit. Sediment depth and silt-clay percentages were measured during the spring at the upper end of each 100-m sampling reach. Sediment depth and percent silt-clay were greater at streams with culverts than at streams with bridges. Sediment depth and silt-clay percentages did not differ between structure and downstream transects for either bridges or culverts; but they were greater at structure transects than at upstream transects only on streams with culverts. Fish diversity, abundance, and richness did not differ between streams with bridges and streams with culverts, nor among sample reaches. Sediment characteristics and fish metrics were not correlated with bridge age in months.
