Ecological Risk Screening Summary - Waterpoppy (Hydrocleys nymphoides)

Species that are considered high risk have a well-documented history of invasiveness in at least one location globally and are of establishment concern for the contiguous United States based on a climate matching analysis.

Hydrocleys nymphoides, Waterpoppy, is a freshwater aquatic plant native to Central America, South America, Puerto Rico, and Trinidad. H. nymphoides grows in shallow, warm, well-lit bodies of water. H. nymphoides has been introduced and established in several countries. It has been introduced in California, Hawaii, Texas, Louisiana, and Florida and is established in California, Texas, and Florida. It has also been introduced and become established in eastern Asia, South Africa, Australia, and New Zealand. H. nymphoides has a high presence in the ornamental trade both within the United States and internationally. The History of Invasiveness for H. nymphoides is classified as High due to this species being established outside its native range and having documented negative impacts from those introductions. Introduced and established populations have resulted in negative impacts such as reduced light penetration, reduced oxygen levels, decreased water quality, altered habitat, decreased land value, clogged drains, blocked dams, and displacement of native flora and fauna. The climate matching analysis for the contiguous United States indicates establishment concern for this species. The climate matching analysis for the contiguous United States found areas of high match in central and southern California, along the Gulf Coast, Southern Atlantic Coast, Mid-Atlantic Coast, and Southeast regions of the United States. The Certainty of Assessment for this ERSS is classified as High. The Overall Risk Assessment Category for H. nymphoides in the contiguous United States is High.