Montana Freshwater Mussels
David Stagliano of the Montana Natural Heritage Program provided the following report on the freshwater mussels of Montana.
"With the completion of Montana’s Comprehensive Fish & Wildlife Conservation Strategy (CFWCS) for native species management in 2006, it became quite apparent that the invertebrate species of the state were lacking basic scientific information. Little attention has been given to Montana’s freshwater mussels since the Henderson reports of 1924 and 1936, but see cursory and regional treatments by Frest and Johannes1995, Gangloff and Gustafson 2000 & McGuire and Marshall 2001. Regardless of this recent work, nothing statewide or comprehensive has occurred.
"The Western Pearlshell (Margaritifera falcata) which is listed as a potential species of concern (S2S24) by NHP came out as an invertebrate species of greatest conservation need (Tier I). Therefore the Montana Natural Heritage Program solicited funds from the State Wildlife Grants (SWG) to implement a comprehensive survey plan to determine distribution & population viability of the 3 native mussel species (the western pearlshell, Margaritifera flacata; the fatmucket, Lampsilis siliquoidaea, the Giant floater, Pyganodon grandis), as well as the recently introduced species; the black sandshell, Ligumia recta, the mapleleaf, Quadrula quadrula and the white heelsplitter, Lasmigona complanata.
"The first year of this three year project focused on the western pearlshell, which was previously reported to exist at ~40 locations (many of these were incidental shell or relic records), but historically has experienced significant range reductions, and may be a possible candidate for the SOC list. As expected, 25 of those 40 previous records or did not contain viable populations."
Summary: 2007 Field Season:
- 266 stream point visits (8/multi-person, 130/2 person, 128/me)
- 18 River Basins visited (4th-code HUC’s)
- avg. reach 300m- 79.8 km or ~50 stream miles evaluated
- 25 of ~40 original reported sites were extirpated or not viable (C, D ranks)
- Recorded only 5 new viable populations (A, B ranks)
References
- Frest, T. J. & E. J. Johannes. 1995. Interior Columbia Basin mollusk species of special concern. Final report to the Interior Columbia Basin Ecosystem Management Project, Walla Walla, WA. Contract #43-0E00-4-9112. 274 pp. plus appendices.
- Gangloff, M. & D. L. Gustafson 2000. The Freshwater Mussels (Bivalvia: Unionoida) of Montana. Vol. 8, Number 1.
- Henderson, J. 1936. Mollusca of Colorado, Utah, Montana, Idaho and Wyoming Supplement. University of Colorado Studies 23(2): 81-145.
- Lippincott, K. & L.B. Davis 2000. A Prehistoric Freshwater Mussel Collection from the Schmitt Chert Mine Site (24BW559) near Three Forks, Montana. Vol. 8, Number 1.
- McGuire, D.L. & D. Marshall. 2001. Current Distribution of the Western Pearl Mussel, Margaritifera falcata, on the Flathead Reservation. Unpublished internal report for the Confederated Salish and Kootenai Tribes, Montana. 7 pp.
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