Abstract
Watershed characteristics impact the habitat and water quality of stream and river ecosystems. In Northwest Iowa, lotic environments are negatively impacted by agricultural practices that result in the removal of riparian vegetation, bank erosion, sedimentation, and eutrophication. Because lotic macroinvertebrates vary in their sensitivity to these types of impacts, they can be used as indicators of habitat integrity. We explored the relative importance of habitat characteristics and allochthonous inputs by examining how macroinvertebrate colonization of leaf packs varied with leaf species, water quality, and stream bank characteristics. Leaf packs were submerged in a reach of the Floyd River at four locations. After four weeks, we collected the packs for analysis. In our 2022 study, we found that richness and abundance of colonizers differed significantly with location, but not with leaf species. We hypothesized that we would see similar results in this study. However, in 2024, richness and abundance did not vary significantly with location. Drought produced low flow conditions in 2022, and historic flooding preceded our 2024 study. These environmental extremes may have eclipsed more subtle local differences due to habitat in the 2024 study. Based on the results of our 2022 study, we hypothesized that colonizer richness and abundance would not significantly vary with leaf species. However, in 2024, we improved our experimental design and included leaves of an invasive species. Despite these changes, macroinvertebrate richness and abundance did not differ with leaf species in this study.
Included in
Macroinvertebrate Colonization of Leaf Packs in the Floyd River
Watershed characteristics impact the habitat and water quality of stream and river ecosystems. In Northwest Iowa, lotic environments are negatively impacted by agricultural practices that result in the removal of riparian vegetation, bank erosion, sedimentation, and eutrophication. Because lotic macroinvertebrates vary in their sensitivity to these types of impacts, they can be used as indicators of habitat integrity. We explored the relative importance of habitat characteristics and allochthonous inputs by examining how macroinvertebrate colonization of leaf packs varied with leaf species, water quality, and stream bank characteristics. Leaf packs were submerged in a reach of the Floyd River at four locations. After four weeks, we collected the packs for analysis. In our 2022 study, we found that richness and abundance of colonizers differed significantly with location, but not with leaf species. We hypothesized that we would see similar results in this study. However, in 2024, richness and abundance did not vary significantly with location. Drought produced low flow conditions in 2022, and historic flooding preceded our 2024 study. These environmental extremes may have eclipsed more subtle local differences due to habitat in the 2024 study. Based on the results of our 2022 study, we hypothesized that colonizer richness and abundance would not significantly vary with leaf species. However, in 2024, we improved our experimental design and included leaves of an invasive species. Despite these changes, macroinvertebrate richness and abundance did not differ with leaf species in this study.