Ecological Risk Screening Summary - Lesser Pond Sedge (Carex acutiformis) - High Risk

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.

Carex acutiformis, also known as the Lesser Pond Sedge, is native to Eurasia—north to Scandinavia and eastward to western China and central Siberia—and Africa. C. acutiformis is found in most wetlands and along a variety of water bodies where it can potentially form extensive monospecific stands. Likely introduced via European hay or other agricultural exports, C. acutiformis has been reported beyond its native range in Canada and the United States. Within the United States, introductions have occurred in the Northeast and Great Lakes regions. C. acutiformis does not appear to disperse well naturally across long distances, although its seeds, rhizome, and root masses could be transplanted via animals, equipment, or vehicles that have passed through established stands. The History of Invasiveness is classified as High as there was information on realized negative impacts of introductions, particularly in Ontario, Canada where C. acutiformis has displaced native vegetation creating dense monocultures. The climate matching analysis for the contiguous United States indicates establishment concern for this species. Regions of particularly high matches were reported from the Atlantic Coast, the Great Lakes region, and portions of the Intermountain West. The Certainty of Assessment for this ERSS is classified as Medium due to the information on impacts of introductions being from grey literature. The Overall Risk Assessment Category for C. acutiformis in the contiguous United States is High.