Ecological Risk Screening Summary - South American Spongeplant (Limnobium laevigatum) - High Risk

Species that are considered high risk have a well-documented history of invasiveness in at least one location globally, and a high or medium climate match to the contiguous United States.

South American Spongeplant, Limnobium laevigatum, is a floating, freshwater aquatic herb native to Mexico, Central and South America and the Caribbean, including Puerto Rico. L. laevigatum is commonly traded around the world for aquariums and aquascapes and reportedly, has a potential role in bioremediation. It has been introduced to and become established in many areas, including California, Nevada and Washington in the United States, Australia, and southern Africa. There are documented impacts from these introductions including, obstructing waterways, reducing water quality, and decreasing the biodiversity. It is regulated in more than one State and is considered a noxious weed by the USDA. The history of invasiveness is classified as High. The overall climate match with the contiguous United States is High, with a medium to high match across much of the United States. The certainty of assessment is Medium. Statements regarding impacts from introduction were found but documentation of the methods used to determine the impacts was not available. The overall risk assessment category is High.