CDC Logo

BC Conservation Data Centre: Conservation Status Report

Rangifer tarandus pop. 1
Caribou (Southern Mountain Population)

 
Scientific Name: Rangifer tarandus pop. 1
English Name: Caribou (Southern Mountain Population)
   
Provincial Status Summary
Status: S1
Date Status Assigned: March 03, 2003
Date Last Reviewed: February 10, 2017
Reasons: Population has declined greatly and continues to decline. Many subpopulations are disjunct, and the smallest populations have so few animals that they are susceptible to extirpation simply due to stochastic events. Loss of old coniferous forests, primarily to logging, leads to increased predation, loss of forage and increased susceptibility to disturbance. Increasing numbers of other ungulate species have further driven up predator populations. Demographic trends to 2002, if continued, are predicted to extirpate all but 2 (possibly even 1) subpopulations. Trends since 2002 show no sign of improvement. Increasing recreation activity at high elevations may represent an equal threat to logging in some areas. There are no fully protected occurrences, and declines have continued despite partial protection offered through land-use plans.
 
Range
Range Extent: F = 20,000-200,000 square km
Range Extent Comments: On the west slope of the Rocky Mountains, Mountain Caribou range from the Anzac through Morkill river drainages and from the Wood through Bush river drainages. Distribution in the Rockies is more-or-less continuous with that in the Cariboo, northern Monashee and northern Selkirk mountains and the eastern Quesnel and eastern Shuswap highlands, an area collectively from Sugarbowl Mountain to the Trans-Canada Highway. Discontinous range occurs to the northwest in the Fraser Plateau near Narrow Lake and Mount George, and to the south in: the southern Monashee Mountains from the Trans-Canada Highway through Fosthall Creek drainage, the northern Purcell and central Selkirk mountains from the Duncan River drainage south almost to Slocan Lake, the Purcell Mountains from the Skookumchuck through Goat river drainages, and the southern Selkirk Mountains from the West Arm of Kootenay Lake to the USA border (where distribution continues southward to Priest Lake, Idaho). Occasional movements or isolated individuals have been reported between all of the discontinous portions of Mountain Caribou range. Range extent, as calcululated using an alpha-hull, is approximately 86,000 sq km.
Area of Occupancy (km2): H = 2,501-12,500
Area of Occupancy Comments: The Mountain Caribou Technical Advisory Committee (2002) mapped more-or-less the maximum extent of each subpopulation using telemetry, census and sightings data. Based on this, densities varied by subpopulation from 3 to 151 animals per 1000 km2. Based only on radiocollared animals, Wittmer (2004) delineated areas of recent occupancy for each subpopulation based on 95% fixed kernels for all animals combined. Wittmer's delineations are more restricted, and likely would indicate less variation in density among populations. He identified 28,400 km2 excluding the South Selkirk subpopulation, so the total would be about 30,000 km2. The apparent recent loss of the George Mountain subpopulation represents a decrease of perhaps 200 km2 from this figure.
Using a 2x2 km grid, the area of occupancy covers approximately 11,000 grid cells.
 
Occurrences & Population
Number of Occurrences: B = 6 - 20
Comments: Heard and Vagt (1998) concluded that there are 12 occurrences (i.e., subpopulations) of the Mountain Caribou ecotype in British Columbia. Simpson et al. (1997) subdivided one of these, resulting in 13 subpopulations that are recognized provincially for management purposes (Mountain Caribou Technical Advisory Committee 2002). Wittmer (2004) analyzed movements of radiocollared Caribou to redefine subpopulation, identifying 18. Since that analysis, the George Mountain subpopulation appears to have been extirpated (D. Seip, Ministry of Forests, pers. comm.). There have also been records of radiocollared resident or previously translocated animals moving between defined subpopulations, and records of non-collared animals in normally unoccupied area between subpopulations, but such activity appears to be uncommon. Based on this, as of 2005 there appear to be about 17 occurrences, i.e. subpopulations that no longer have significant interchange of animals with other such subpopulations.
Number of Occurrences with Good Viability / Ecological Integrity: B = 1 - 3
Comments: Based on demographic data to 2002, Wittmer (2004) determined cumulative median extirpation probabilities of 100% within 200 years for 14 subpopulations, about 80% for 1, and 0% for 1 (2 were not analyzed but their demographic characteristics are poorer than many of the 14 predicted for extirpation). Since that analysis, 1 subpopulation appears to have been extirpated (D. Seip, Ministry of Forests, pers. comm.). Using a generation time of 6.7 years (Thomas and Gray 2002), 5 generations would be about 33 years. Interpolating from charts showing frequency distributions of extirpation probabilities (Wittmer 2004), 6 subpopulations have at least 95% probability of persistence for 33 years. However, of these 6, only 2 maintained stable populations from 2002 to 2004 (Mountain Caribou Technical Advisory Committee, unpubl. data). Thus, there appear to be 2 occurrences with good viability, 15 with poor viability, and 1 that has been extirpated.
Number of Occurrences Appropriately Protected & Managed: B = 1 - 3
Comments: National parks, provincial parks and ecological reserves that provide at least partial protection to areas regularly or occasionally occupied by Mountain Caribou include: Arctic Pacific Lakes, Evanoff, Sugarbowl-Grizzly Den, Ptarmigan Creek, West Twin, Close to the Edge, Upper Rausch, Mount Tinsdale, Bowron Lake, Cariboo Mountains, Wells Gray, Upper Adams, Foster Arm, Cummins Lakes, Goosegrass, Glacier, Mount Revelstoke, Monashee, Goat Range, Purcell Wilderness, Kianuko, Lockhart Creek, West Arm and Stagleap. However, with the exception of the Wells Gray/Cariboo Mountains/Bowron Lakes park system, most parks provide only minimal protection of critical habitats. Additional protection of habitat and in some cases protection from human disturbance is offered by a series of local land-use plans (Mountain Caribou Technical Advisory Committee 2002). However, these do not appear adequate in most cases as only 2 subpopulations have over 50 animals and remained stable from 2002 to 2004 (Mountain Caribou Technical Advisory Committee unpubl. data).
Population Size: D = 1,000 - 2,500 individuals
Comments: The 2004 estimate was 1669 animals (Mountain Caribou Technical Advisory Committee, unpubl. data). Given high rates of mortality and low calf recruitment in recent years, this can be assumed to included very roughly 10% calves, 10% yearlings, and 10% post-reproductive animals. Assuming first reproduction at 16 months for females (Rettie and Messier 1998) and at 28 months for males, and a 1:1 sex ratio, there would have been ~1250 animals of reproductive age in 2004.
 
Threats (to population, occurrences, or area affected)
Degree of Threat: A = Very high
Comments: The most immediate threat to the smallest subpopulations is simply random events eliminating the few remaining individuals (Cichowski et al. 2004). Much of this is the result the high predation rate (Cichowski et al. 2004; Wittmer 2004) resulting from altered predator-prey systems, which in turn are brought about largely by loss of old-forest habitat. Predators, primarily wolves and Cougars, are supported by large populations of Moose, White-tailed Deer, Mule Deer and Elk, all of which obtain food from early-seral forests and other disturbed areas. Broad-scale expansions of these species within Mountain Caribou range since the mid 1800s allowed wolf and cougar numbers and distribution to expand (Seip 1992; Heard and Vagt 1996; Seip and Cichowski 1996; Kinley 2002). At finer scales, the increasing overlap between caribou and predators due to the conversion of old forests to cutblocks and roads (James and Stuart-Smith 2000; Kinley and Apps 2001) is likely to continue this trend. In addition to creating unsustainable predation levels, loss of old forests ultimately will place a limit on carrying capacity as it relates to the availability of arboreal lichens for winter forage. Disturbance due to human recreation, such as snowmobiling, cat-skiing, heliskiing and backcountry ski touring, may also affect recruitment or survival (Simpson and Terry 2000) or cause range abandonment (Kinley 2003). There is increasing interest in recreational snowmobiling, combined with better access due to more technically advanced machines and roads built for high-elevation cutblocks. Industrial development (logging, mining and oil development) can potentially affect caribou, either through displacement or increased predation rates (Smith 2004). Vehicle or train collisions and poaching have resulted in the loss of many caribou in the recent past (Stevenson and Hatler 1985; Compton et al. 1995; Almack 2000), although the continued extent of this is unknown. Mortality from falls, avalanches and other natural accidents resulted in at least 13% of known mortalities among collared Mountain Caribou (Wittmer 2004).
 
Trend (in population, range, area occupied, and/or condition of occurrences)
Short-Term Trend: EF = Decline of 10-50%
Comments: Thomas and Gray (2002) determined generation length to be about 6.7 years, or 20 years for 3 generations. Using 2 methods to extrapolate past populations, Hatter et al. (in prep.) estimated the 1984 population at 2349-2356. This equates to a 3-generation reduction of 29-35%, based on a 2004 population estimate of 1669 (Mountain Caribou Technical Advisory Committee unpubl. data). The rate of decline appears to have accelerated since 1995, and the current rate of decline is estimated at 10%/year (Hatter et al. in prep).
Long-Term Trend: BD = Decline of 50-90%
Comments: Although its absolute magnitude is unknown, there was a widespread decline in Mountain Caribou during the last century (Demarchi 1999; Spalding 2000). The initial decline has been linked to the spread of Moose into the province and the subsequent increase in wolf numbers and predation rates on Caribou (Seip 1991, 1992; Seip and Cichowski 1996), and ongoing increases in predation due to alteration of old-forest habitats and over-hunting (Mountain Caribou Technical Advisory Committee 2002; Cichowski et al. 2004). One estimate is that Mountain Caribou have been extirpated from approximately 43% of their historic range in BC and 60% of their historic range in BC and the United States (Ministry of Environment, Lands and Parks 2001). Historic numbers have been crudely estimated by 2 investigators at between 5,000 and 6,000 (Demarchi 1999) and less than 7,000 (D. Spalding, pers. comm., cited in Demarchi 1999).
 
Other Factors
Intrinsic Vulnerability: B=Moderately vulnerable
Comments: Mountain Caribou appear to be highly vulnerable to loss of old-forest habitat, as it affects forage availability, predation rates and potentially displacement The natural conditions occurring within their range at the time of European contact appear to have represented close to one extreme in the range of natural environmental variability for that region (i.e. old forests were widespread, other ungulates and their predators were less common, human disturbance was minimal). Thus, almost all forms of human resource-use activity appear to negatively affect Mountain Caribou. Conversely, Mountain Caribou are highly mobile and are adapted to a winter food source many other ungulates cannot use effectively, and under ideal conditions a female Caribou may produce up to 10 offspring in her lifetime. When limiting factors are moderated, populations can expand.
Environmental Specificity: B=Narrow. Specialist or community with key requirements common.
Comments: Where predation is minimal, Mountain Caribou live within areas spanning a range of moisture regimes (moist to very wet) and forest cover types. However, due to the influence of early-seral forests on the abundance of other ungulates that attract predators, negative demographic trends are associated with the conversion of old forest to young forest (Wittmer 2004). Thus, in the absence of human intervention to reduce alternative prey species or their predators, Mountain Caribou are specifically tied to landscapes dominated by old forest. Habitat selection assessments throughout Mountain Caribou range show strongest selection by Mountain Caribou for older forests (Apps and Kinley 2000b, 2000c; Hamilton et al. 2000; Apps et al. 2001; Johnson et al. 2004; Kinley and Apps, in prep.).
Other Rank Considerations: At least 98% and possibly over 99% of the world's Mountain Caribou live entirely within British Columbia. Recovery efforts have had limited success so far. For example, the translocation of 103 animals into the South Selkirk subpopulation between 1987 and 1998 (Almack 2000), while probably preventing extirpation, has resulted in this group currently having only about 33 animals (Mountain Caribou Technical Advisory Committee unpubl. data). Virtually all subpopulations of Mountain Caribou have declined in recent years, with the rate apparently accelerating (ibid., Hatter et al. in prep.), despite the recent enactment of habitat-protection provisions.
 
Information Gaps
Research Needs: The relationship between alternate prey (other ungulates), predators (wolf, Cougar, bear, Wolverine) and Mountain Caribou, particularly as they relate to the amount and interspersion of early seral habitats with old forest, should be researched further.
Inventory Needs: Routine inventories of the entire metapopulation (17 extant occurrences, 1 presumed extirpated occurrence), preferably at 2- to 3-year intervals, must be completed to maintain a good understanding of numbers and trends. Opportunities to explore the degree of Caribou activity between recognized subpopulations (sightings by the public, vehicle collisions, etc.) should be acted upon.
 
Stewardship
Protection: See Management Needs.
Management: A population viability assessment is required to determine the probability of metapopulation extinction and subpopulation extirpations based on current and potential management regimes. These would update the static predictions made by Wittmer (2004). There must be at least short-term and potentially ongoing reductions in numbers of other ungulates and their predators within Mountain Caribou range to stem rapid Caribou losses. Several small subpopulations are likely to become extirpated within 1 to 3 generations without the translocation of additional Caribou. Captive breeding and maternal penning may be required in some cases. Old forest, in the amounts and distribution determined by the population viability analysis, needs to be reserved or potentially harvested under modified silvicultural regimes. Simpson et al. (1997), Stevenson et al. (2001) and Seip (1998) recommend an interconnecting mosaic of reserves and integrated management areas to maintain long-term viability of the species. Additional research is needed to determine the influence of various silvicultural prescriptions on caribou predation risk and forage. This information then needs to be incorporated into policy and management actions (Simpson et al. 1997). Where recreation- or industrial-based disturbances limit the use of preferred habitats, such activities must be prevented or carefully managed. The impacts of snowmobiling and other backcountry recreation activities on caribou (behavioural and physiological responses to disturbance, displacement from critical habitats, population consequences of disturbance, and potential for habituation) needs to be investigated.
 
Version
Author: Kinley, T. A.
Date: February 01, 2005
 
References
Almack, J.A. 2000a. Mountain caribou recovery in the southern Selkirk Mountains of Washington, Idaho, and British Columbia. Prog. rep. October 1998 - March 2000. Washington Dep. Fish and Wildl., Olympia, WA.
Apps, C., and T. Kinley. 2000b. Multiscale habitat modeling for mountain caribou in the Columbia Highlands and Northern Columbia Mountains ecoregions, British Columbia. Prepared for Minist. Water, Land and Air Prot., Williams Lake, BC. Aspen Wildl. Res., Calgary, AB.
Apps, C., and T. Kinley. 2000c. Multi-scale habitat associations of mountain caribou in the southern Purcell Mountains, British Columbia. Prepared for East Kootenay Environ. Soc., Kimberley, BC, and Tembec Industries Inc., Cranbrook, BC. Aspen Wildl. Res., Calgary, AB.
Apps, C., B. McLellan, T. Kinley, and J. Flaa. 2001. Scale-dependent habitat selection by Mountain Caribou, Columbia Mountains, British Columbia. J. Wildl. Manage. 65(1):65-77.
Banfield, A.W.F. 1974. The mammals of Canada. Univ. of Toronto Press, Toronto, Can. 438pp.
British Columbia Ministry of Water, Land and Air Protection. 2004aa. Caribou in Accounts and measures for managing identified wildlife. British Columbia Ministry of Water, Land and Air Protection, Victoria, BC. 52pp.
Compton, B.B., P. Zager, and G. Servheen. 1995. Survival and mortality of translocated woodland caribou. Wildl. Soc. Bull. 23:490-496.
Demarchi, D.N. 1999. Population trends of the big game species in British Columbia. Draft. B.C. Wildl. Fed., Surrey, and B.C. Conserv. Found., Surrey.
Hamilton, D., S.F. Wilson, and G. Smith. 2000. Mountain caribou habitat use and population characteristics for the Central Selkirks Caribou Inventory Project. Prepared for Pope and Talbot Ltd., Nakusp, BC, Meadow Creek Cedar, Kaslo, BC, Slocan Forest Products Ltd., Slocan, BC, and Minist. Environ., Lands and Parks, Nelson, BC by Nanuq Consulting Ltd., Nelson, BC.
Hatter, I.W., J. Quayle, and L.R. Ramsay. A conservation status assessment of the mountain caribou ecotype based on IUCN red list criteria. Minist. Water, Land and Air Prot., Victoria, BC. (in prep.).
Heard, D.C., and K.L. Vagt. 1996. The status of caribou in British Columbia in 1996. Unpubl. rep. B.C. Minist. Environ., Land and Parks, Prince George. 11pp. plus tables and figures.
Heard, D.C., and K.L. Vagt. 1998. Caribou in British Columbia: A 1996 status report. Rangifer, Spec. Issue 10:117-123.
James, A.R.C., and A.K. Stuart-Smith. 2000. Distribution of caribou and wolves in relation to linear corridors. J. Wildl. Manage. 64:154-159.
Johnson, C.J., D.R. Seip, and M.S. Boyce. 2004. A quantitative approach to conservation planning: using resource selection functions to identify important habitats for mountain caribou. J. Appl. Ecol. 41:238-251.
Kinley, T. 2002b. Background information for public consultation regarding the proposed translocation of caribou from the Itcha-Ilgachuz Mountains to the southern Purcell Mountains. Prepared for Columbia Basin Fish and Wildl. Compensation Program, Nelson, BC, and Minist. Water, Land and Air Prot., Nelson, BC. Sylvan Consulting Ltd., Invermere, BC.
Kinley, T. 2003a. Snowmobile - mountain caribou interactions: a summary of perceptions and an analysis of trends in caribou distribution. Prepared for Minist. Water, Land and Air Prot., Victoria, BC by Sylvan Consulting Ltd., Invermere, BC.
Kinley, T., and C. Apps. 2001. Mortality patterns in a subpopulation of endangered mountain caribou. Wildl. Soc. Bull. 29(1):158-164.
Ministry of Environment, Lands and Parks. 2001. Wildlife populations in British Columbia. Technical background document: environmental trends in British Columbia. State of the Environ. Reporting office, Victoria, BC.
Mountain Caribou Technical Advisory Committee (MCTAC). 2002. A Strategy for the Recovery of Mountain Caribou in British Columbia. B.C. Minist. Water, Land and Air Prot., Biodiv. Branch. Recovery Plan RP-02. 85pp.
Nagorsen, D. 1990. The mammals of British Columbia: a taxonomic catalogue. Mem. No. 4. Royal B.C. Mus., Victoria. 140pp.
Rettie, W.J., and F. Messier. 1998. Dynamics of woodland caribou populations at the southern limit of their range in Saskatchewan. Can. J. Zool. 76:251-259.
Seip, D., and D.B. Cichowski. 1996. Population ecology of the Caribou in British Columbia: Rangifer, Spec. Issue No. 9:73-80.
Seip, D.R. 1991. Predation and caribou populations. Rangifer Spec. Issue 7:46-52.
Seip, D.R. 1992. Factors limiting woodland caribou populations and their interrelationships with wolves and moose in southeastern British Columbia. Can. J. Zool. 70:1494-1503.
Seip, D.R. 1998. Ecosystem management and the conservation of caribou in British Columbia. Rangifer Spec. Issue 10:203-212.
Simpson, K., and E. Terry. 2000. Impacts of Backcountry Recreation Activities on Mountain Caribou. B.C. Minist. Environ., Lands and Parks, Wildl. Branch. Working Rep. WR-99. 12pp.
Simpson, K., E. Terry, and D. Hamilton. 1997. Toward a Mountain Caribou management strategy for British Columbia - habitat requirements and sub-population status. B.C. Minist. Environ., Lands and Parks, Wildl. Branch. Victoria. Wildl. Working Rep. WR-90. 29pp.
Smith, K.G. 2004. Woodland caribou demography and persistence relative to landscape change in west-central Alberta. Thesis, Univ. Alberta, Edmonton, AB.
Spalding, D.J. 2000. The Early History of Woodland Caribou (Rangifer tarandus caribou) in British Columbia. B.C. Minist. Environ., Lands and Parks, Wildl. Branch. Wildl. Bull. B-100. 61pp.
Stevenson, S.K. et al. 2001. Mountain Caribou in Managed Forests: Recommendations for Managers, 2nd edition. B.C. Minist. Environ, Lands and Parks, Wildl. Branch. Tech. Rep. R-26. 71pp.
Stevenson, S.K., and D.F. Hatler. 1985b. Woodland caribou and their habitat in southern and central British Columbia. Volume 2. Land Manage. Rep. No. 23, B.C. Minist. For., Victoria.
Thomas, D.C., and D.R. Gray. 2002. Update COSEWIC status report on the woodland caribou Rangifer tarandus caribou in Canada. Committee on the Status of Endangered Wildlife in Canada. Ottawa. xi + 98pp.
Wittmer, H.U. 2004. Mechanisms underlying the decline of mountain caribou (Rangifer tarandus caribou) in British Columbia. Dissertation, Univ. British Columbia, Vancouver, BC.
 

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. 2005. Conservation Status Report: Rangifer tarandus pop. 1. B.C. Minist. of Environment. Available: https://a100.gov.bc.ca/pub/eswp/ (accessed Apr 25, 2024).