Aquatic Vegetation and Fish Community Monitoring at the Emiquon Nature Preserve

Floodplains provide many ecosystem services, including biodiversity, fish and wildlife refuge, flood-peak reduction, shoreline stabilization, groundwater recharge, sediment. accretion, nutrient uptake, as well as recreational, educational, research, economic, and aesthetic services. River connectivity is critical for maintaining ecosystem integrity and services. The Illinois River is one example of a productive floodplain river system, but its natural biological productivity has changed through floodplain disconnection, elevated nutrient inputs, and invasive fish species introductions. Cun-ently, floodplain restoration efforts are intended to benefit and improve the Illinois River, as well as others throughout the Midwest. Thompson and Flag lakes at The Nature Conservancy's Emiquon Nature Preserve serve as one example and have sustained a diverse (10 species) and abundant native submersed aquatic vegetation community that is othe1w ise difficult to find within the Illinois River valley today. As the diversity and plant density increased has since restoration, so has the species richness and biomass of native fishes. However, common ca1v ( Cyprinus cmpio) are present in the Emiquon Preserve and management is critical for maintaining balance in aquatic ecosystems. Because rotenone is not 100 percent effective, additional research on largemouth bass (Micropterus salmoides), bowfin (Amia calva), and gars (Lepisosteus) has been conducted and suggests that they cannot control common ca1p population growth through direct predation. Additionally, research has been conducted to assess how the aquatic vegetation and fish communities respond to river connection and natural flood events. The knowledge gained from this research will continually serve useful for the Emiquon Preserve and future floodplain restoration projects.