Ecological Risk Screening Summary - Duck Lettuce (Ottelia alismoides) - 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.

Ottelia alismoides, Duck Lettuce, is an aquatic plant that is native to Southeast Asia, China, India, and northern Australia. This species has been documented outside of its native range in Egypt, Iraq, Italy, Sudan, Tanzania, and the United States. Within the United States Ottelia alismoides is listed as a noxious weed by the USDA and is prohibited within a number of states. Although this species is listed as a noxious weed there are data deficiencies with regards to its impacts of introductions, resulting in a history of invasiveness classification of Data Deficient. The climate match score for the contiguous United States is High. The majority of the contiguous United States had medium to high match with areas of low match in the northeast and pacific northwest. The certainty of assessment is classified as Low due to a lack of information relating to its history of invasiveness. The overall risk assessment category is Uncertain.