Ecological Risk Screening Summary - Yellow Velvetleaf (Limnocharis flava) - 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.

Limnocharis flava is a prolific plant native to tropical and subtropical America, with a far-reaching range of northwestern Mexico to Brazil and includes several Caribbean nations. The plant shows a preference for shallow swamps, ditches, pools, wet rice fields, and stagnant fresh water. L. flava offers a wide range of human uses including forage for wildlife, ornamental, food for humans, manure, medicinal and research. One or more of these benefits led to introductions in many countries throughout Southeast Asia. However, these introductions have also led to negative biological and economic impacts. For example, in some areas infestations became so severe that they forced abandonment of rice fields and created blockage of water flow in other areas. Infestations can also provide unwanted breeding grounds for disease-vectors and restrict wetland habitat for native aquatic plants and animals. A single plant produces over one million seeds a year that can easily spread by water, birds, man, or with infested crops such as rice. While distribution within the contiguous United States is unclear, the species has been reported as an ornamental plant in private ponds and has been cultivated by Missouri Botanical Gardens. It was listed as a noxious weed in Florida in 2002, designated as a “Prohibited aquatic plant, Class 1.” Climate match within the contiguous United States is medium, with Florida, Georgia, South Carolina, and Texas providing high matches. Given its high history of invasiveness, medium climate match, and documented negative impacts of introduction, the overall risk of Limnocharis flava within the United States is high.