Date of Award
Master of Science
Anthropogenic impacts have degraded the function of many large river-floodplain ecosystems. Habitat rehabilitation/management, in the form of water level management, often emphasize the promotion of wetland vegetation. Wetland management is believed to enhance macroinvertebrate populations. To test this assumption, I evaluated macroinvertebrate response to habitat rehabilitation, habitat type, and vegetation density in Swan Lake, an Illinois River floodplain lake located in Calhoun County, Illinois. Results indicated wetland rehabilitation generally enhanced macroinvertebrate availability for spring migrating waterfowl. Results comparing habitats available at Swan Lake indicated moist soil habitats provided greater abundance and biomass of water column macroinvertebrates in the fall season, while spring was more variable. In addition, benthic macroinvertebrate communities indicated inconsistent differences between habitat types. Fall estimates indicated inundation can be an effective mechanism for controlling the timing of water column macroinvertebrate colonization. Vegetation manipulations did not consistently impact macroinvertebrate taxonomic and functional groups, but results indicated some specific taxonomic groups were influenced by vegetation presence/absence and were correlated (positively or negatively) with coarse organic matter. This research supported the principle that management of habitat and hydrologic regime can be effective tools for improving macroinvertebrate populations in order to optimize nutritional resources for waterfowl.
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