Cooperative Fish and Wildlife Research Units Program: Iowa
Education, Research and Technical Assistance for Managing Our Natural Resources

Invasive species and hydrologic alterations from navigation, flood control, and hydroelectric dams are among the most serious stressors present in the Upper Mississippi River basin. Both stressors can inflict ecosystem-level effects including the restructuring of food webs through increased competition, predation, habitat alteration, water quality degradation, and fragmentation. Bigheaded carp (Hypophthalmichthys molitrix and Hypophthalmichthys nobilis) are high-profile invasive species in North America that are continuing to expand upstream in the Mississippi River basin. In response, many state and federal agencies partner to reduce the undesirable effects of invasive carp through early detection, barrier management, and removal. Despite these programs, our understanding of the full consequences of bigheaded carp invasions is incomplete hampering our ability to enact scientifically led decision making to control their spread as well as understanding the ecosystem impacts they can have at different densities.

We assess the effects of these invasive planktivores on a variety of trophic guilds using stable isotope analyses across a natural gradient of invasive carp density in Iowa.