Ecological Risk Screening Summary - Seminole Ramshorn (Planorbella duryi) - Uncertain Risk

Planorbella duryi, Seminole Rams-horn, is a mollusk that is native to the Florida Peninsula. P duryi can inhabit both man-made and natural freshwater systems, including thermally
regulated waters. This species has become a very popular aquarium snail. Many other hard-to-distinguish planorbid snail species are also popular aquarium snails. Hawaii has listed any species in the genus Helisoma on their conditional list, which would include a synonym of P. duryi. The History of Invasiveness for P. duryi is classified as Data Deficient due to P. duryi being established outside of its native range, with a lack of clear, convincing, and reliable documentation of impacts or lack of impacts from introductions. The climate match analysis for the contiguous United States indicates establishment concern for this species outside its native range. The climate match for P. duryi was highest in the Southeast, including the native range and areas surrounding the native range. The Certainty of Assessment for this ERSS is classified as Low due to the limited available information regarding P. duryi’s history of invasiveness. The Overall Risk Assessment Category for Planorbella duryi in the contiguous United States is Uncertain.

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.