Ecological Risk Screening Summary - Narrowleaf Anacharis (Elodea naias) - Uncertain Risk

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

Elodea naias, Narrowleaf Anacharis, is an aquatic plant that is native to South America. E. naias is a dioecious, submerged, perennial forb found in freshwater. It is present in the aquarium trade. An established population of E. naias was found in Florida but has since been eradicated through human intervention. It is also recorded as introduced in Asia and possibly Europe, having established populations in southeastern China and peninsular Malaysia. Information regarding nuisance characteristics, including impacts to power generation, was available from the species’ native range. However, no information was available regarding impacts from introduced non-native populations. The History of Invasiveness for E. naias is classified as Data Deficient due to the lack of information on impacts from introduced populations.E. naias is regulated in California. The climate matching analysis for the contiguous United States indicates establishment concern for this species. Climate matching was high for the contiguous United States across portions of the Gulf Coast, Southeast, and Peninsular Florida regions. The Certainty of Assessment for this ERSS is classified as Low due to unknown impacts caused by introductions and lack of information about nonnative populations outside the United States. The Overall Risk Assessment Category for E. naias in the contiguous United States is Uncertain.