Ecological Risk Screening Summary - American Eelgrass (Vallisneria americana) - 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.

American eelgrass (Vallisneria americana) is a freshwater plant native to parts of the contiguous United States, Central America, South America, and Canada. It has also been listed as native to Asia and Australia but those populations may be separate species. This species is in the aquarium trade and legally imported around the world, but records of the volume traded was not found. V. americana is introduced and established in Belgium, Indonesia, Timor-Leste, Taiwan, and nonnative areas of the United States, such as Hawaii. It is reported as harmful in Indonesia and Timor-Leste but no supporting information for that statement could be found. The history of invasiveness is classified as Data Deficient because no information on impacts of introduction was found. The overall Climate match for the contiguous United States was High. Nearly the entire United States had a high or medium match, only a few tiny areas had a low match. Areas of high match were centered on the native range in the eastern United Sates and areas with established nonnative populations in the western United States. The certainty of assessment is Low due to lack of information on impacts. The overall risk assessment category for Vallisneria americana is Uncertain.