Winged MapleleafQuadrula fragosa
At one time the federally endangered winged mapleleaf inhabited at least 34 river systems in 12 states (USFWS 1997). Quadrula fragosa (Conrad 1835) is now thought to occur in select reaches of St. Croix River, Wisconsin, Kiamachi River, Oklahoma, and Bourbeuse River, Missouri. One of the last known reproducing populations occurs in the St. Croix River where the river forms the border between Minnesota and Wisconsin. Until very recently winged mapleleaf were thought to occur only downstream of the St. Croix Falls dam. In 1999 and 2001 Hove et. al found dead valves above the St. Croix Falls Dam, suggesting a greater distribution of this mussel in the St. Croix. We are currently examining possible relocation sites above the dam for Winged Mapleleaf mussels that be produced in propagation trials.
More information regarding the factors that may have lead to the decline of the winged mapleleaf mussels can be found in the flyer produced by the Fish and Wildlife Service. A PDF copy of the flyer can be found here. The Recovery Plan for this species as a PDF is at http://ecos.fws.gov/docs/recovery_plan/970625.pdf. Dan Hornbach was a member of the recovery team developing this plan.
Hove, M. C., L. A.
Cunningham, K. G. Esse, and D. J.
Hornbach. 1999. Range extension of the federally endangered winged
mapleleaf: valves collected from upper St. Croix River, Minnesota.
Triannual Unionid Report 18: 9.
Hove, M. C., D. C. Allen, R. S. Derhak, K. M. Swenson, J. E. Thomas, and D. J. Hornbach. 2001. Second collection of winged mapleleaf valves from the upper St. Croix River. Ellipsaria 3(2): 11-12.
U.S. Fish and Wildlife Service. 1997. Winged mapleleaf mussel (Quadrula fragosa) recovery plan. Fort Snelling, Minnesota. 69 pp.