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.
Hawaii Arrowhead (Sagittaria sagittifolia) is a wetland plant native to Eurasia. This plant can grow in water up to 4 ft as well as in muddy conditions. It reproduces both by seed and vegetatively. S. sagittifolia has been used as a food source and for medicinal properties. The history of invasiveness is High. The plant has been introduced into other countries including Australia, New Zealand and Mexico and established populations there. This species is currently listed as a Federal Noxious Weed, and is banned from several States but some trade in the tubers as a food source has been allowed. There is information regarding impacts from S. sagittifolia invasion including impacts on crop production and water chemistry. Climate matching indicated the contiguous United States has a high climate match. Areas of high match were spread across the contiguous United States. However, there may be much of the species’ range that is not represented in the source points used for the climate match due to a lack of available data. The certainty of assessment is medium, mostly due to the gap in distribution data for the climate match. The overall risk assessment category is High.