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.
Elodea (Elodea canadensis) is a freshwater, aquatic plant that is native to North America. The plant grows fully submerged except for its flowers. E. canadensis is a popular plant sold in the aquarium trade to increase the available oxygen in a tank. The history of invasiveness is high. E. canadensis has been introduced around the world, mainly as an escapee from captivity, and has established populations on every continent except for Antarctica. E. canadensis invasions have resulted in local extirpations or near extirpation of native plant species, changes in use of lake depth by native species, decreases in crayfish populations, and altered abiotic conditions of a lake (pH, dissolved CO2 and O2, turbidity, phosphorus). Dense beds of E. canadensis can interfere with commercial (preventing navigation) and recreational (fishing, swimming, boating) usage of waterways, clog irrigation channels, and interfere with hydropower and municipal water supplies. E. canadensis is native to much of the lower 48 and there are established populations across the contiguous United States; it has a correspondingly high climate match across the same area. The certainty of assessment is high, peer-reviewed literature is available regarding the assessment elements. The overall risk assessment category is high.
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High Risk
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