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.
Azolla caroliniana, the Carolina Mosquitofern, is an aquatic plant native to much of the eastern United States, Central and South America, as well as the Caribbean. This species has been introduced to many countries to be used in agriculture as a green fertilizer, for horticultural and ornamental purposes, and pest control. A. caroliniana has become established outside of its native range in Hawaii, Spain, France, Italy, Ukraine, and China. Some information on impacts of introduction were found including competition with native plants, some of which are locally threatened, interference with recreational activities, and it can change water quality and hydrology. Information on documented negative impacts of introduction was available, therefore the history of invasiveness is High. The climate match for the contiguous United States was High, with high match found throughout the native range in the eastern States, with additional areas of high match found in the West and Midwest. The certainty of this assessment is Medium, due to the taxonomic confusion of the Azolla genus and primary sources for the impacts of introduction not being available in English. The overall risk assessment category for Azolla caroliniana is High.
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High Risk
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