Ecological Risk Screening Summary - Greater European Peaclam (Pisidium amnicum) - Uncertain Risk

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.

Pisidium amnicum, Greater European Peaclam, is a mollusk that is native to the Palearctic region. The native range is described as encompassing most of Europe to Siberia in Russia and northern Africa. P. amnicum is a small clam that prefers soft bottoms of lakes, rivers, and streams. It has been introduced to the Great Lakes, Hudson River, and St. Lawrence River in the United States and Canada. P. amnicum was likely introduced to the contiguous United States through shipping in the early 1900s. Impacts from those introduced populations have not yet been documented. The History of Invasiveness for Pisidium amnicum is classified as Data Deficient due to the lack of clear, convincing, reliable characterizations of impacts or lack of impacts. The climate matching analysis for the contiguous United States indicates establishment concern for this species. The climate match for Pisidium amnicum to the contiguous United States was highest in the Midwest and Northeast, especially around the Great Lakes. The Certainty of Assessment is classified as Low due to the lack of information regarding impacts from introductions and possible gaps in the representation of the native range in the climate matching analysis. The Overall Risk Assessment Category for Pisidium amnicum in the contiguous United States is Uncertain.