Flowering rush creates dense stands that impede water flow and damage fishing, hunting, boating, and other recreational activities. It acts as an ecosystem engineer, creating floating mats and encouraging sedimentation under dense stands. It invades previously non-vegetated areas, displaces native plant species, increases water temperature, alters habitat structure and nutrient cycling, and may provide substrate for invasive mussels as well as aquatic snails serving as the intermediate host for the swimmer’s itch parasite. In some locations, such as the Columbia Basin, there is concern that flowering rush can provide increased habitat for predatory non-native fish species, including northern pike and smallmouth bass which feed on native trout and salmonid species.