Benthos in Brushy and Meadow Habitats of a Central Wisconsin Trout Stream

Abstract

Monthly benthos samples were collected in an upstream Meadow Zone and in two downstream Brushy Zones of a small brook trout (Salvelinus fontinalis) stream from April 1972 through April 1973. Benthic density and biomass were much higher in the Meadow Zone than in both Brushy Zones. The total and [weighted] mean number of organisms was 1430/m^2 [322/m^2] in the Meadow Zone and they decreased to 440/m^2 [1.37 /m^2] in the adjacent downstream Brushy Control Zone. The total and weighted mean biomass in the Meadow Zone was 15.71g/m^2 [3.47g/m^2] and lowest in the Brushy Control Zone, 4.51g/m^2 [1.36g/m^2]. Benthic density and biomass were highest in vegetation and gravel substrates, found only in the Meadow Zone, and they decreased in detritus and sand substrates, respectively. Mean density and biomass in detritus and sand substrates were also highest in the Meadow Zone compared to downstream Brushy Zones. Flooding, which occurs infrequently, resulted in the lowest numbers and biomass encountered during the study. Results from. this study support brush removal as a management technique for improving the food base for trout in small heavily shaded streams.