Abstract
Stream ecosystems are influenced by their watersheds. Intact watersheds support high water quality and habitat heterogeneity, while providing native allochthonous input. In Iowa, watershed degradation associated with agricultural activities and expanding residential development negatively impacts streams by increasing sedimentation, pesticide exposure, and eutrophication. Our study continued a monitoring program of a low order stream in Sioux County, Iowa. As the surrounding watershed shifts from agricultural to residential use, we are recording changes in stream biodiversity and water quality. At three study sites, we documented the stream’s physical and chemical characteristics and collected macroinvertebrate samples. We also introduced various substrata (gravel, maple leaves, and pavers) to the stream to observe macroinvertebrate colonization. As expected, we found the stream dominated by taxa tolerant of poor water quality. Our results indicate that substrate type significantly affected colonization, with gravel supporting the lowest richness and abundance of macroinvertebrates. Overall, location and colonization month (September vs. October) only affected a subset of our samples. These results differ markedly from those of a similar 2018 study. We anticipate that the results of this study will be compared to future work, enabling researchers to monitor how the stream responds to changes in the watershed and hydrological events.
Included in
Monitoring a Small Northwestern Iowa Stream Undergoing Watershed Changes
Stream ecosystems are influenced by their watersheds. Intact watersheds support high water quality and habitat heterogeneity, while providing native allochthonous input. In Iowa, watershed degradation associated with agricultural activities and expanding residential development negatively impacts streams by increasing sedimentation, pesticide exposure, and eutrophication. Our study continued a monitoring program of a low order stream in Sioux County, Iowa. As the surrounding watershed shifts from agricultural to residential use, we are recording changes in stream biodiversity and water quality. At three study sites, we documented the stream’s physical and chemical characteristics and collected macroinvertebrate samples. We also introduced various substrata (gravel, maple leaves, and pavers) to the stream to observe macroinvertebrate colonization. As expected, we found the stream dominated by taxa tolerant of poor water quality. Our results indicate that substrate type significantly affected colonization, with gravel supporting the lowest richness and abundance of macroinvertebrates. Overall, location and colonization month (September vs. October) only affected a subset of our samples. These results differ markedly from those of a similar 2018 study. We anticipate that the results of this study will be compared to future work, enabling researchers to monitor how the stream responds to changes in the watershed and hydrological events.