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.
Trapa natans is an annual floating leaved aquatic plant native to large areas of Eurasia and Africa. A single plant can produce multiple floating rosettes of leaves and produce up to 20 spined nuts. T. natans can have a 10-fold growth rate and the nuts may be viable for up to 10 years. T. natans has been used as a food source for humans and domesticated animals, for medicinal purposes, and it has been proposed for industrial uses. The history of invasiveness for T. natans is high. It has been intentionally planted as an ornamental or food source. Impacts of this aquatic plant include the shading out and replacement of native submerged aquatic plants and severely reducing dissolved oxygen levels. Climate matching indicated the contiguous United States has a high climate match. This species is already established in parts of the Northeast. Certainty of this assessment is high. The overall risk assessment category is high.
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High Risk
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