Synopsis Aquatic plants are an important part of freshwater systems. They perform a wide variety of ecological functions. They provide nesting sites, cover and food for all kinds of aquatic life, including fish, waterfowl and smaller animals. Plants invigorate the water body by increasing oxygen concentrations in the water and sediments. Rooted aquatic plant communities help secure and stabilize shorelines. In some cases aquatic plants help improve water clarity by competing for nutrients with algae. These are but a few of the beneficial roles that aquatic plants play. Under certain conditions, however, aquatic plants can become a problem. Excess growth of aquatic plants can affect beneficial uses of a water body, such as recreational and aesthetic enjoyment, irrigation and water supply uses, and wildlife habitat. In addition, invasion by non-native (exotic) plant species. Such as Eurasian watermilfbil, can seriously damage an aquatic ecosystem. Exotic weeds can choke out native vegetation, and can form dense stands that are a nuisance to humans and create poor habitat for fish and wildlife.