An evaluation of fisher (Martes pennanti) introductions in Montana

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Translocations can play a crucial role in the conservation and restoration of wildlife populations. The author investigated the impact of translocations on the distribution and genetic structure of fisher populations in Montana. Ten years after the release of 110 fishers from Minnesota and Wisconsin to the Cabinet Mountains of northwestern Montana, the author conducted surveys to document the distribution of fisher. During three winters, verifiable detections were made in four of 17 systematically surveyed sampling units. Surveys revealed that fishers are rare, but present and reproducing in an area where they were believed to be absent prior to the introduction. To establish the occupied range of fisher throughout Montana and examine the evidence for its historic extirpation, all available records on the species’ past and present distribution were gathered. Historic records were scarce, but indicate that fisher occurred in western Montana. No fishers were harvested in the state from 1929 to 1959, suggesting that they were extirpated from Montana. Contemporary occurrence data from harvest, snow tracking, and sightings were used to map fisher distribution statewide. The spatial and temporal distribution of these records demonstrates that translocations have been successful in establishing, and/or augmenting, fisher populations in Montana. Verified fisher records exist in the Bitterroot, Coeur d’Alene, Sapphire, Garnet, Mission, Swan, Cabinet, Purcell, Whitefish, Flathead,Livington, and Beartooth ranges. To investigate the origin of extant populations in Montana, fisher tissue samples from Montana, British Columbia, Minnesota, and Wisconsin were collected, and two regions of the mitochondrial DNA genome were examined. Haplotype frequencies differed significantly by region. Source populations had seven non-overlapping haplotypes: four unique to British Columbia, two to the Midwest, and one to west-central Montana. The distribution of these haplotypes in Montana suggests that fisher populations in the state have multiple origins, reflecting their history of translocations and the influence of native populations. Contrary to historic data, analysis of mitochondrial DNA sequence data indicates that fisher may not have been extirpated from Montana and/or Idaho prior to the translocations. West-central Montana fisher populations show evidence of isolation and distinctiveness, suggesting that they are descended in part from remnant native populations.

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ELECTRONIC FILE - Zoology

Citation: Vinkey, R. S. 2003. An evaluation of fisher (Martes pennanti) introductions in Montana. Unpublished master's thesis, University of Montana, Missoula. 97 pp.