Effects of Stream Channelization on Aquatic Macroinvertebrates, Buena Vista Marsh, Portage County, Wisconsin

[摘要] Project objectives were to determine the effects ofstream channelization on biomass and composition of streambenthos and drift and on water quality and temperature.Drift and substrate-stratified, quantitative benthos sampleswere collected and stream discharge measured in upstream anddownstream new ditch, old ditch, and natural stream sites,at approximately 6-week intervals during the ice-free periodof the year. Water chemistry samples were collected atapproximately 6-week intervals throughout the year andtemperatures recorded continuously with thermographs.Benthic biomass and density were lowest in sand andhigher in aquatic vegetation, silt-detritus, and gravel(productive substrates) , which provided stable surfaces forreattachment of drifting invertebrates and interstices forentrapment of drifting seston. Benthic biomass and densitywere positively correlated, whereas drifting invertebratebiomass and density, and density of drifting seston, werenegatively correlated with percent composition of theproductive substrates.Percent composition of the productive substrates washighest in the natural stream, followed by the old and newditch in the upstream area, and highest in the new ditch,followed by the old ditch and natural stream in thedownstream area.Water quality and temperature, similar among sites,probably were moderated by groundwater inflow.

[发布机构] University of Wisconsin-Stevens Point, College of Natural Resources