Ecological Risk Screening Summary - Floating Watermoss (Salvinia natans) - Uncertain Risk

Species that are considered uncertain risk need a more in-depth assessment beyond the Risk Summary to better define the species’ risk to U.S. environments.

Floating watermoss, Salvinia natans, is an aquatic plant native to Europe, Asia, and northern Africa. This species is found in the aquarium trade in the United States and is listed as a prohibited species in Texas. S. natans has been reported as introduced in the United States but no populations are currently established. It has also been reported as introduced and established in Jamaica and Cuba. Impacts have been reported from the Kashmir region of Central Asia, where it grows in thick mats that cause changes in water temperature and reduce dissolved oxygen concentrations, potentially affecting native plant and fish health. However, sources do not agree on the nonnative status of S. natans in Kashmir, so the history of invasiveness is Data Deficient. The overall climate match for the contiguous United States is High, with the highest matches occurring in the Great Lakes and north-central regions. The certainty of assessment is Low due to limited information on establishment and impacts of introduction. The overall risk assessment category for Salvinia natans is Uncertain.