Scientific Name: | Pekania pennanti pop. 5 |
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English Name: | Fisher - Columbian Population |
Provincial Status Summary | |
Status: | S2 |
Date Status Assigned: | March 31, 2020 |
Date Last Reviewed: | February 11, 2020 |
Reasons: | Fisher, Columbian population, occurs over a large range in the central interior of BC. Population numbers are low, estimated between 299-517 individuals. Threats are high, with forest harvesting being the most significant, along with habitat loss and degradation, and trapping where habitats are compromised. Recent trends have shown declines of 30-50% due to loss of forest habitat; current conditions suggest declines may be accelerating. This population has been extirpated from most of the Shuswap, Okanagan, Columbia and Kootenay regions. |
Range | |
Range Extent: | G = 200,000-2,500,000 square km |
Range Extent Estimate (km2): | 229,868 |
Range Extent Comments: | The Columbian population of Fisher (Weir et al. 2024) is found through low to moderate elevations within forested habitat in the central interior of BC (Weir 2003, Lofroth et al. 2010). Range extent is the total area within the extent of fisher distribution with a habitat capability rating greater than nil (Lofroth 2004). The extent of occurrence estimated at 229,868 sq. km. Fishers are no longer distributed within 78,320 sq. km of their former range, primarily in areas south of the Thompson River, the Adams River drainage and lands east, and the Kootenays and Columbia regions. Fishers still occupy suitable landscapes within parts of the Bridge River drainage, the Chilcotin, Cariboo, Omineca, Williston, Nechako, Takla, Bulkley and Skeena. Efforts to re-establish fisher populations in the East Kootenay region of the formerly occupied range (Fontana et al. 1999, Fontana and Teske 2000) were not successful (Weir et al. 2003). |
Area of Occupancy (km2): | H = 2,501-12,500 |
Area of Occupancy Estimate (km2): | 43,824 |
Area of Occupancy Comments: | The estimate of area of occupancy was based on total range extent with a habitat capability rating of moderate or better (Lofroth 2004) as per previous status assessments. Habitat loss and degradation concerns for fishers are not new (Weir, 2003, Lofroth et al. 2010; Bridger et al. 2016), however recent large-scale events (Mountain Pine Beetle infestations, wildfires, and subsequent salvage harvest) have increased those concerns (Eng et al., 2005, Forest Practices Board 2018) due to increases in areas without forest cover (open areas). Area of occupancy was further evaluated using an open area analysis based on an established relationship between fisher occupancy and forest cover (Weir and Corbould 2010). Results suggest that 71% of potentially occupied landscape has a current relative probability of occupancy of less than 20% (Weir unpub. data) due to current habitat condition. Consequently, area of occupancy has been reduced by this amount. Area of occupancy is currently estimated at 43824 square kilometres (10,956 2x2 km grid cells) (E. Lofroth, pers. comm. 2020). |
Occurrences & Population | |
Number of Occurrences: | U = Unknown |
Comments: | No analyses currently exist that inform the number of fisher occurrences. Ongoing population and genetic analyses may better inform this in future. |
Number of Occurrences with Good Viability / Ecological Integrity: | U = Unknown |
Percent Area with Good Viability / Ecological Integrity: | U = Unknown |
Comments: | Portions of some fisher populations may exist within protected areas however they may be limited because fisher are distributed primarily within low and moderate elevation habitats (Weir 2003, Lofroth et al. 2010). Protected areas have also been affected by mountain pine beetle infestations and wildfire. |
Number of Occurrences Appropriately Protected & Managed: | Rank Factor not assessed |
Population Size: | C = 250 - 1,000 individuals |
Comments: | Population size was estimated using methods detailed in Lofroth (2004) and density estimates of 11.7 fishers/1000 sq. km (Weir and Corbould 2006). Areal extent of each class of fisher habitat capability were reduced, consistent with findings of the open area analyses used to determine area of occupancy. Columbian fisher populations are currently estimated at 299-517. Ongoing inventory work for fishers in Chilcotin and Williston regions may refine these estimates in future (E. Lofroth, pers. comm. 2020). |
Threats (to population, occurrences, or area affected) | |
Degree of Threat: | B = High |
Comments: | A threats calculator was completed by a group of experts in 2018, resulting in a score of High. Primary threats are forest harvesting. Accelerated harvests due to wildfire and mountain pine beetle salvage exacerbate these threats. Secondary threats are loss or degradation of habitat due to agriculture, transportation, and wildfire, and threats to populations from trapping where habitats are compromised (E. Lofroth, pers. comm. 2020). |
Trend (in population, range, area occupied, and/or condition of occurrences) | |
Short-Term Trend: | E = Decline of 30-50% |
Comments: | Occupancy analyses suggest continued and extensive declines in abundance. Declines have been suggested consistently in the past (Banci 1989, Weir 2003). Current conditions suggest declines may be accelerating (E. Lofroth, pers. comm. 2020). |
Long-Term Trend: | D = Decline of 50-70% |
Comments: | Declines include historic extirpation from most of the Shuswap, Okanagan, Columbia and Kootenay regions and recent loss of forested habitat within the current area of extent (E. Lofroth, pers. comm. 2020). |
Other Factors | |
Intrinsic Vulnerability: | B=Moderately vulnerable |
Comments: | Factors that contribute to the intrinsic vulnerability include low reproductive output and low survival rates (Lofroth et al. 2010). |
Environmental Specificity: | B=Narrow. Specialist or community with key requirements common. |
Comments: | Fishers use specific habitat features primarily found in late-successional forests (Lofroth et al. 2010, Raley et al. 2012). This requirement is most specific for natal and maternal dens, where atypically large black cottonwood, trembling aspen, Douglas-fir or lodgepole pine trees are used by the females (Davis 2009, Weir and Harestad 2003, Weir and Corbould 2008). Attributes for resting locations are also tied to features of older successional stages (Aubry et al 2013). |
Other Rank Considerations: | |
Information Gaps | |
Research Needs: | Landscape occupancy models need to be further refined, evaluated and tested for the entire range of Columbian fisher. Landscape models that delineate priority conservation areas for fishers and assist in prioritization of habitat protection and restoration are needed. Improvements in understanding linkages between habitat condition and demographic parameters (survival and reproduction) are key to developing effective conservation and management approaches. Trials and refinement of fisher exclusion devices for trapping need to continue. Evaluation of interim management measures to bridge habitat loss (e.g., fisher den boxes) should continue (E. Lofroth, pers. comm. 2020). |
Inventory Needs: | Inventory is required within areas affected by mountain pine beetle and subsequent wildfire and forest harvest. Inventory is needed within areas where fisher abundance and distribution are poorly understood, especially Bulkley, and Skeena areas (E. Lofroth, pers. comm. 2020). |
Stewardship | |
Protection: | |
Management: | Fisher require appropriate habitat management at landscape and stand scales. Voluntary guidance is currently available for stand level management but requires consistent application to be effective (BC Fisher Habitat Web Module 2020). Landscape management requires the use of data-driven landscape models to identify high priority conservation areas for extant fisher habitat and to prioritize areas of high fisher habitat capability for protection and restoration (E. Lofroth, pers. comm. 2020). |
Version | |
Author: | Lofroth, E. |
Date: | February 11, 2020 |
References | |
Aubry, K.B., C.M. Raley, S.W. Buskirk, et al. 2013. Meta-analyses of habitat selection by fishers at resting sites in the Pacific coastal region. J. Wildl. Manag. 77(5):965?974.
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Banci, V. 1989. A fisher management study for British Columbia. B.C. Minist. Environ., Wildl. Bull. B-63. Victoria. 127pp.
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BC Fisher Habitat Working Group. British Columbia Fisher Habitat and Forestry Web Module. Available: http://www.bcfisherhabitat.ca (accessed 31 January 2020).
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Bridger, M.C., C.J. Johnson, and M.P. Gillingham. 2016. Assessing cumulative impacts of forest development on the distribution of furbearers using expert-based habitat modeling. Ecological Applications. 26(2): 499?514.
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Davis, L.R. 2009. Denning ecology and habitat use by fisher (Martes pennanti) in pine dominated ecosystems of the Chilcotin Plateau. M.Sc. Thesis, Simon Fraser Univ., Burnaby, BC.
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Eng, M., A. Fall, J. Hughes, et al. 2005. Provincial level projection of the current Mountain Pine Beetle outbreak: An overview of the model and results of Year 2 of the project. Natural Resources Canada. Mountain Pine Beetle Initiative Working Paper.
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Fontana, A.J., and I.E. Teske. 2000. East Kootenay Fisher Reintroduction Program. P. 693 in L.M. Darling, ed. 2000. Proc. Conf. on the Biology and Manage. Species and Habitats at Risk, Kamloops, B.C., 15-19 Feb., 1999. Vol. 2; B.C. Minist. Environ., Lands and Parks, Victoria, BC, and Univ. College of the Cariboo, Kamloops, BC. 520pp.
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Fontana, A.J., I.E. Teske, and K. Pritchard. 1999. East Kootenay fisher reintroduction program final report 1996-1999. Minist. of Environ., Lands, and Parks, Cranbrook, BC. Canada.
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Forest Practices Board. 2018. Timber Salvage Harvesting and Fisher Management in the Nazko Area. Complaint Investigation #16037. FPB/IRC/217.
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Lofroth, E. 2004. Fisher (Martes pennanti) British Columbia Population Science Assessment Review. Minist. of Water, Land and Air Protection, Victoria, B.C. 21 pp.
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Lofroth. E.C., C.R. Raley, J.M. Higley, et al. 2010. Conservation of fishers (Martes pennanti) in south-central British Columbia, western Washington, western Oregon, and California - Volume I: Conservation Assessment. USDI Bureau of Land Management, Denver, Colorado, USA.
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Raley, C.M., E.C. Lofroth, R.L. Truex, et al. 2012. Habitat ecology of fishers in western North America: a new synthesis. Pages 231 - 254 in K.B. Aubry, W.J. Zielinski, M.G. Raphael, et al., eds. Biology and conservation of martens, sables, and fishers: a new synthesis. Comstock Publishing Associates, Cornell University Press, Ithaca, NY, USA.
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Weir, R.D, Rankin, A.M., Robinson, L., Pilgrim, K.L, Schwartz, M.K, and Lucid, M.K. 2024. Genetic structuring of fishers in British Columbia,Canada: implications for population conservation and management. Journal of Mammalogy. 105 (3) 465:480.
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Weir, R.D. 2003. Status of the Fisher in British Columbia. B.C. Minist. Water, Land and Air Prot., Biodiversity Branch, and B.C. Minist. Sustainable Resour. Manage., Conservation Data Centre Victoria, BC. Wildl. Bull. B-105. 47pp.
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Weir, R.D., and A.S. Harestad. 2003. Scale-dependent habitat selectivity by fishers in south-central British Columbia. J. Wildl. Manag. 67:73-82.
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Weir, R.D., and F.B. Corbould. 2006. Densities of fishers in the Sub-Boreal Spruce biogeoclimatic zone of British Columbia. Northwest Naturalist 87: 118-127.
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Weir, R.D., and F.B. Corbould. 2008. Ecology of Fishers in the Sub-boreal Forests of North-central British Columbia: Final Report. Peace/Williston Fish and Wildlife Compensation Program Report No. 315. 178 pp plus appendices.
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Weir, R.D., and F.B. Corbould. 2010. Factors affecting landscape occupancy by fishers in north-central British Columbia. J. Wildl. Manag. 74:405-410.
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Weir, R.D., I.T. Adams, and A.J. Fontana. 2003. East Kootenay fisher assessment. Unpub. rep. prepared for Minist. of Water, Land and Air Protection. BC. 31pp.
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Please visit the website Conservation Status Ranks for information on how the CDC determines conservation status ranks. For global conservation status reports and ranks, please visit the NatureServe website http://www.natureserve.org/.
B.C. Conservation Data Centre. 2020. Conservation Status Report: Pekania pennanti pop. 5. B.C. Minist. of Environment. Available: https://a100.gov.bc.ca/pub/eswp/ (accessed Feb 6, 2025).