Species that are considered uncertain risk need a more in-depth assessment beyond the Risk Summary to better define the species’ risk to U.S. environments.
Azolla microphylla is an aquatic fern species that is potentially native to parts of both North and South America. A. microphylla has been used as a green fertilizer, animal feed, natural filter for waste treatment, and large populations may be useful for reducing mosquito populations. The taxonomic confusion within the Azolla genus has made it difficult to determine what information can be correctly attributed to this species. The history of invasiveness is classified as Data Deficient. Introductions have resulted in established populations in South Africa, Mozambique, and Bangladesh. Some information regarding impacts to water quality for human consumption were reported from a survey of residents near a large infestation. The climate match with the contiguous United States is high. The climate match indicates that there is suitable climate for an expansion of this species outside the known current range. The certainty of this assessment is low because of a lack of information reliably pertaining to A. microphylla, and the taxonomic confusion of Azolla in general, which also reduces the certainty in the information regarding the range of the species and the interpretation of the climate match results. The overall risk assessment category is Uncertain.
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Uncertain Risk
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