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.
Curly leaved pondweed (Potamogeton crispus) is a plant native to Eurasia, Africa, and Australia. The submerged macrophyte is used in medical treatments, as habitat and food for wildlife, and in restoration projects due to its tolerance of polluted conditions. However, the history of invasiveness is high. Concerns with this plant include competition with native plants, reduced biodiversity, altered water flow in canals, and impacts on water-based recreation. P. crispus can alter nutrient cycles and deplete dissolved oxygen levels through the species’ interesting spring and fall growth patterns. Climate matching indicated the contiguous United States has a very high climate match. This is unsurprising, given the species is established in all 48 contiguous States. The plant has shown a capability to establish in most eutrophic systems. Certainty of this assessment is high. The overall risk assessment category is high.