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BC Conservation Data Centre: Conservation Status Report

Pekania pennanti
Fisher

 
Scientific Name: Pekania pennanti
Scientific Name Synonyms: Martes pennanti
English Name: Fisher
   
Provincial Status Summary
Status: S3
Date Status Assigned: April 27, 2015
Date Last Reviewed: March 31, 2020
Reasons: This is the conservation status rank and report for Fisher at the species level. Status assessments have also been completed for the Boreal and Columbian Fisher populations, which are available through the CDC BC Species and Ecosystem Explorer tool.

Although widespread over close to half of the province, this species is not numerous (estimated at 1195-2036 animals) and is vulnerable to habitat loss through logging, hydro-electric development or other land use changes, and to trapping where habitats are compromised.
 
Range
Range Extent: G = 200,000-2,500,000 square km
Range Extent Estimate (km2): 459,268
Range Extent Comments: Fisher is found through low to moderate elevations within forested habitat in the central interior and boreal regions of BC (Weir 2003, Lofroth et al. 2010). Recent (2019) research has identified two genetically separate populations - the Columbian and Boreal populations (Weir et al. in prep.). 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 is estimated at 459,268 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). Records of fishers at the northwestern limit of their range within southern Yukon have increased in the past three decades (Jung and Slough 2011) but is unclear if this observation suggests possible population growth in adjacent BC or expansion due to climate change (E. Lofroth, pers. comm. 2020).
Area of Occupancy (km2): I = >12,500
Area of Occupancy Estimate (km2): 175,594
Area of Occupancy Comments: The estimate of area of occupancy for the Columbian fisher population 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 <20% (Weir unpub. data) due to current habitat condition. Consequently, area of occupancy has been reduced by this amount. The estimate of area of occupancy for the Boreal fisher population was based on total area of range extent with a habitat capability rating of moderate or better (Lofroth 2004) as per previous status assessments. The area of occupancy has not been further reduced as models analogous to Weir and Corbould (2010) do not exist for this element. Area of occupancy is likely less than estimated due to lands that are unlikely to be occupied by fishers due to anthropogenic disturbances that have changed forest cover. Total area of occupancy is currently estimated at 175,594 square kilometres (43,899 2x2km 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
Number of Occurrences Appropriately Protected & Managed: U = Unknown
Comments: Unknown. 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, particularly within the range of the Columbian fisher population have also been affected by mountain pine beetle infestations and wildfire (E. Lofroth, pers. comm. 2020).
Population Size: D = 1,000 - 2,500 individuals
Comments: Population size for the Columbian fisher population 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. Ongoing inventory work for fishers in Chilcotin and Williston regions may refine these estimates in future. Population size for the Boreal fisher population was estimated using methods detailed in Lofroth (2004) and density estimates of 16.3 fishers/1000 sq. km (Weir et al. 2011). Fisher populations are currently estimated at 1195-2036 (E. Lofroth, pers. comm. 2020).
 
Threats (to population, occurrences, or area affected)
Degree of Threat: B = High
Comments: 2018: Threats were assessed as High by a group of experts. Significant threats include included logging and wood harvesting and trapping (E. Lofroth, pers. comm. 2020).

2015: Forestry, hydro-electric development and trapping are of the greatest concern to Fishers (J. Krebs, pers. comm.; E. Lofroth, pers. comm.; R. Weir, pers. comm.). The mountain pine beetle outbreak has exacerbated the loss of forested habitat. Loss of habitat through the cutting for conversion to other land uses (urban, semi-rural and agriculture), over-trapping and the widespread use of poisons as a harvest and predator control method have also contributed to the reduction and extirpation of Fisher populations (Douglas and Strickland 1987; Handley 1991). Forest harvesting also increases access for trappers. Fishers are taken in Marten sets, and Marten trapping is a mainstay of BC's fur industry.
 
Trend (in population, range, area occupied, and/or condition of occurrences)
Short-Term Trend: EF = Decline of 10-50%
Comments: Occupancy analyses for the Columbian fisher population 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. No occupancy analyses or current inventory are available to inform this factor for the Boreal fisher population. Declines have been suggested consistently in the past (Banci 1989, Weir 2003). Fisher?s strong relationships with forest cover (Lofroth et al. 2010, Raley et al. 2012) suggest declines due to loss of forest cover to industrial activities (primarily oil and gas and forestry) are probable (E. Lofroth, pers. comm. 2020).
Long-Term Trend: E = Decline of 30-50%
Comments: Declines within the Columbian fisher population include historical extirpation from most of the Shuswap, Okanagan, Columbia and Kootenay regions and recent loss of forested habitat within the current area of extent. Declines within the Boreal fisher population are currently more difficult to assess due to limited data but are expected due to extensive industrial development and agriculture over the past 100 years (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, balsam popular, trembling aspen, Douglas-fir or lodgepole pine trees are used by the females (Davis 2009, Weir and Harestad 2003, Weir and Corbould 2008, Weir et al. 2012). Attributes for resting locations are also tied to features of older successional stages (Weir 2010; Aubry et al 2013).
Other Rank Considerations:
 
Information Gaps
Research Needs: Landscape occupancy models for the Columbian fisher population 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. Landscape occupancy models for the Boreal fisher population need to be developed to inform land management decisions within the range extent for Boreal fisher. Research is required to evaluate effects of extensive oil and gas development on fisher habitat value within the range extant of Boreal fisher (E. Lofroth, pers. comm. 2020).
Inventory Needs: Inventory for the Columbian fisher population 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. Inventory for the Boreal fisher population is required for areas where fisher abundance and distribution are poorly understood, especially boreal forest regions in the northeast of BC. Inventory is also needed in areas most affected by industrial development (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:
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.
Banci, V. 1989. A fisher management study for British Columbia. B.C. Minist. Environ., Wildl. Bull. B-63. Victoria. 127pp.
BC Fisher Habitat Working Group. British Columbia Fisher Habitat and Forestry Web Module. Available: http://www.bcfisherhabitat.ca (accessed 31 January 2020).
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.
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.
Douglas, C.W., and M.A. Strickland. 1987. Fisher. Pages 511-529 in M. Novak, J.A. Baker, M.E. Obbard, and B. Malloch, eds. Wild furbearer management and conservation in North America. Ontario Trapper's Assoc., North Bay, ON.
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.
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.
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.
Forest Practices Board. 2018. Timber Salvage Harvesting and Fisher Management in the Nazko Area. Complaint Investigation #16037. FPB/IRC/217.
Handley, C.O. Jr. 1991. Mammals. Pages 539-616 in K. Terwilliger, coordinator. Virginia's endangered species: proceedings of a symposium. McDonald and Woodward Publishing Company, Blacksburg, Virginia.
Jung, T.S., and B.G. Slough. 2011. The status of fishers (Martes pennanti) at the northwestern edge of their range: Are they increasing and expanding in the Yukon? Northwest Naturalist 92:57-64.
Lofroth, E. 2004. Fisher (Martes pennanti) British Columbia Population Science Assessment Review. Minist. of Water, Land and Air Protection, Victoria, B.C. 21 pp.
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.
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.
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.
Weir, R.D. 2010. Ecology of fishers in the boreal mixedwood forests of northeastern British Columbia Year-end Report 2009-10. Unpub. rep. prepared for Louisiana Pacific, BC Ministry of Environment and Encana Corp. 54pp.
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.
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.
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.
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.
Weir, R.D., E.C. Lofroth and M. Phinney. 2011. Density of fishers in boreal mixedwood forests of northeastern British Columbia. Northwestern Naturalist 92:65-69.
Weir, R.D., E.M. Phinney and E.C. Lofroth. 2012. Big, sick and rotting: Why tree size, damage, and decay are important to fisher reproductive habitat. Forest Ecology and Management 265:230-240.
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.
 

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/.

Suggested Citation:

B.C. Conservation Data Centre. 2020. Conservation Status Report: Pekania pennanti. B.C. Minist. of Environment. Available: https://a100.gov.bc.ca/pub/eswp/ (accessed Jun 30, 2024).