Proceedings of the 2022 Mississippi Water Resources Conference

Year: 2022 Authors: Ervin G.N., Turnage G., Lazaro-Lobo A.

Resource managers of public lands, such as national wildlife refuges, are tasked with meeting multiple use needs of the fish and wildlife that reside on these lands, as well as the people who utilize those lands for recreational activities such as fishing, boating, and wildlife watching. Biologists at the Sam D. Hamilton Noxubee National Wildlife Refuge (NNWR) have identified the dominance of certain problematic aquatic plants as a key obstacle to achieving these multiple use needs in lakes and associated wetlands on this and other southeastern wildlife refuges. Few methods are currently known that allow the control of some of the problematic aquatic plant species that they encounter, while simultaneously enhancing the diversity of desirable species, maintaining water quality, and providing diverse aquatic habitats that are needed for many species of wildlife and for human users of these facilities.

This project was aimed at determining optimally effective methods of managing invasive and problematic aquatic plants to enhance wetland plant diversity in a way that improves the quality of wetlands as wildlife habitat and sources of recreational use, while also minimizing potential negative impacts on water quality and desirable native plant species. We tested a variety of chemical control measures (herbicides) to reduce the abundance of key nuisance plant species, while attempting to minimize negative impacts on key water quality parameters (e.g., dissolved oxygen, nitrogen, and phosphorus). We found that all three herbicides tested gave long-term reduction of white water lily and water shield, but a timing mismatch in the phenology of these species and American lotus resulted in failure to control the latter species. None of the water quality parameters that were monitored indicated substantial negative impacts of the herbicide treatments.