Caribou (Rangifer tarandus) barren-ground population COSEWIC assessment and status report 2016: chapter 2

Technical summary

Scientific name:
Rangifer tarandus
English name:
Caribou, Barren-ground population (Designatable Unit 3)
French name:
Caribou, population de la toundra (Unité désignable 3)
Range of occurrence in Canada (province/territory/ocean):
Northwest Territories, Nunavut, Yukon, Saskatchewan, Manitoba, Alberta

Demographic information

Demographic information
Summary items Information
Generation time
(Calculated using IUCN guidelines (2008))
8-9 years
Is there a projected continuing decline in number of mature individuals? Yes
Estimated percent of continuing decline in total number of mature individuals within 2 generations Unknown
Estimated percent reduction in total number of mature individuals over the last 3 generations. Estimated at 57% for 7 subpopulations with sufficient information to quantify trends, representing ~70% of the total current population
Suspected percent increase in total number of mature individuals over the next 3 generations. Unknown, but based on past dynamics, where marked fluctuations in abundance have been documented in some subpopulations, numbers may increase within three generations. However, there is uncertainty to this prediction due to ongoing cumulative changes to the environment and unknown success of management actions.
Estimated percent reduction in total number of mature individuals over any 3 generations period, over a time period including both the past and the future. ~57%
Are the causes of the decline clearly reversible and understood and ceased? Causes of declines are complex and not well understood.
Reversible: possibly.
Ceased: no.
Are there extreme fluctuations (>1 order of magnitude) in number of mature individuals? Insufficient information to assess

Extent and occupancy information

Extent and Occupancy Information
Summary items Information
Estimated extent of occurrence 4,253,842 km2
Index of area of occupancy (IAO) (Always report 2x2 grid value). 247,840 km2 (calving grounds; calculated only for 8 subpopulations with sufficient data)
Is the population severely fragmented? No
Number of locations Unknown, but certainly > 14
Is there an observed continuing decline in extent of occurrence? Extent of occurrence fluctuates with abundance, thus recent annual areas for some subpopulations are reduced from maximum recorded abundance in the 1990s
Is there an observed continuing decline in index of area of occupancy? Range size changes with abundance, thus recent annual areas in some subpopulations are reduced from maximum recorded abundance in the 1990s
Is there an observed continuing decline in number of populations As many as three subpopulations may have disappeared within the past three generations
Is there an observed continuing decline in number of locations? Uncertain
Is there an observed continuing decline in area of habitat? Yes
Are there extreme fluctuations in number of populations? No
Are there extreme fluctuations in number of locations? No
Are there extreme fluctuations in extent of occurrence? No
Are there extreme fluctuations in index of area of occupancy? No

Number of mature* individuals (in each subpopulation)

Number of Mature* Individuals (in each subpopulation)
Subpopulation (year of most recent survey) N Individuals
1. Porcupine (2013) 197,000
2. Tuktoyaktuk Peninsula (2015) 1,701
3. Cape Bathurst (2015) 2,259
4. Bluenose-West (2015) 15,268
5. Bluenose-East (2015) 38,592
6. Bathurst (2015) 19,769
7 (8). Beverly/Ahiak (2011) 195,529
9 & 10. Lorillard + Wager Bay (2002) 41,000
11. Boothia Peninsula (1995) 6,658
12. Qamanirjuaq (2014) 264,661
13. Southampton Island (2015) 12,297
14. Coats Island (1991) 500
15. Baffin Island (2014) 4,856
Total (extrapolated from estimates and trends to 2015) ~800,000

* Population estimates are of all individuals

Quantitative Analysis

Quantitative analysis
Summary items Information
Probability of extinction in the wild is at least 20% within 5 generations.
(Population viability analyses [PVAs] are not available)
Not done.

Threats (actual or imminent, to populations or habitats)

Threats (actual or imminent, to populations or habitats)
Summary items Information
  • Disturbances from human activity
  • Climate-mediated habitat and weather changes
  • Over-hunting
  • Predation
  • Pathogens and insects (may intensify under a warmer climate)

Rescue effect (immigration from outside Canada)

Rescue Effect (immigration from outside Canada)
Summary items Information
Status of outside population(s)? Three subpopulations in Alaska may be part of this DU, but have not been evaluated. All three are currently declining.
Is immigration known or possible? Unknown but unlikely
Would immigrants be adapted to survive in Canada? Yes
Is there sufficient habitat for immigrants in Canada? Yes
Is rescue from outside populations likely? No

Data Sensitive Species

Data sensitive species
Summary items Information
Is this a data sensitive species? No

Status history

Status History
Summary items Information
COSEWIC: Designated Threatened in November 2016.

Status and reasons for designation:

Status and Reasons for Designation:
Summary items Information
Status Threatened
Alpha-numeric codes Meets Endangered, A2acd+4acd, but designated Threatened because it does not appear to be facing imminent extinction or extirpation.
Reasons for designation Members of this population give birth on the open arctic tundra, and most subpopulations (herds) winter in vast subarctic forests. Well-known for its large aggregations, lengthy migrations, and significant cultural and social value to northern Aboriginal Peoples and other Canadians, its 14-15 subpopulations range from northeastern Alaska to western Hudson Bay and Baffin Island. Numbering more than 2 million individuals in the early 1990s, the current population is estimated at about 800,000. Most subpopulations have declined dramatically, but two are increasing, including the Porcupine Caribou Herd. For 70% of the population with sufficient data to quantify trends, the decline is estimated at 56% over the past three generations (since 1989), with several of the largest herds having declined by >80% from peak numbers. Available survey data for an additional 25% of the total population also indicate declines. Evidence from both local Aboriginal people and scientific studies suggests that most herds have undergone natural fluctuations in numbers in the past; however, available demographic data indicate no sign of rapid recovery at this time and cumulative threats are without historical precedent. Status meets criteria for Endangered because of a reduction in numbers of ≥50%, but Threatened is recommended because, overall, this population does not appear to be facing imminent extinction at this time. Despite worrisome declines across most of the range, the current numerical abundance of the Porcupine Caribou Herd and the initiation of numerous management actions by governments, wildlife management boards, and communities support Threatened as a more appropriate conservation status. The status of these subpopulations will have to be carefully monitored and may warrant re-assessment within five years.

Applicability of criteria

Applicability of Criteria
Summary items Information
Criterion A (Decline in Total Number of Mature Individuals) Meets Endangered A2acd, with 3-generation decline of 56% estimated for 70% of the population (based on aerial surveys [a], with habitat quality decline [c] and exploitation [d] also driving population decline), with an additional 25% of the population undergoing unquantified declines; trends for the remaining 5% are unknown. Also meets A4acd (past and future), because some ongoing decline is predicted based on current demographic information and ongoing threats.
Criterion B (Small Distribution Range and Decline or Fluctuation) Not applicable.
Criterion C (Small and Declining Number of Mature Individuals) Not applicable.
Criterion D (Very Small or Restricted Population) Not applicable.
Criterion E (Quantitative Analysis) Not applicable.


Several designatable units (hereafter referred as DUs, formerly “populations”) of caribou (Rangifer tarandus) have been assessed more than once by COSEWIC (COSEWIC 2002; 2004; 2014a,b; 2016). All are currently listed under Schedule 1 of SARA. This status report for Barren-ground Caribou (DU3) follows an analysis of designatable unit structure of caribou in Canada undertaken by COSEWIC as a special project (COSEWIC 2011) to define the DUs for future status assessments and reassessments of this species according to the latest guidelines (COSEWIC 2015). Although prevailing taxonomy (Banfield 1961) recognizes four native extant and one extinct subspecies in North America, it is out of date and does not capture the variability of caribou across their range in Canada. Based on the COSEWIC DU criteria for discreteness and significance (COSEWIC 2015), Barren-ground Caribou were recognized as a DU (COSEWIC 2011) and are assessed here for the first time.

This status report benefited from the simultaneous drafting of a status report in development for assessment under the territorial Species At Risk (NWT) Act (SARC 2016). The traditional knowledge section of that report was a particularly important source of ATK, as were products from subpopulation-specific caribou hearings and conservation actions being conducted in NWT and NU. This report also includes updates from traditional ecological knowledge collected and summarized from First Nations and Métis sources by the COSEWIC Aboriginal Traditional Knowledge (ATK) Subcommittee. These sources have been compiled and assessed in two reports: the Caribou ATK Source Report and the Caribou ATK Assessment Report.

A map of place names referred to in this report is in Appendix A.

COSEWIC history

The Committee on the Status of Endangered Wildlife in Canada (COSEWIC) was created in 1977 as a result of a recommendation at the Federal-Provincial Wildlife Conference held in 1976. It arose from the need for a single, official, scientifically sound, national listing of wildlife species at risk. In 1978, COSEWIC designated its first species and produced its first list of Canadian species at risk. Species designated at meetings of the full committee are added to the list. On June 5, 2003, the Species at Risk Act (SARA) was proclaimed. SARA establishes COSEWIC as an advisory body ensuring that species will continue to be assessed under a rigorous and independent scientific process.

COSEWIC mandate

The Committee on the Status of Endangered Wildlife in Canada (COSEWIC) assesses the national status of wild species, subspecies, varieties, or other designatable units that are considered to be at risk in Canada. Designations are made on native species for the following taxonomic groups: mammals, birds, reptiles, amphibians, fishes, arthropods, molluscs, vascular plants, mosses, and lichens.

COSEWIC membership

COSEWIC comprises members from each provincial and territorial government wildlife agency, four federal entities (Canadian Wildlife Service, Parks Canada Agency, Department of Fisheries and Oceans, and the Federal Biodiversity Information Partnership, chaired by the Canadian Museum of Nature), three non-government science members and the co-chairs of the species specialist subcommittees and the Aboriginal Traditional Knowledge subcommittee. The Committee meets to consider status reports on candidate species.

Definitions (2016)

Wildlife species
A species, subspecies, variety, or geographically or genetically distinct population of animal, plant or other organism, other than a bacterium or virus, that is wild by nature and is either native to Canada or has extended its range into Canada without human intervention and has been present in Canada for at least 50 years.
Extinct (X)
A wildlife species that no longer exists.
Extirpated (XT)
A wildlife species no longer existing in the wild in Canada, but occurring elsewhere.
Endangered (E)
A wildlife species facing imminent extirpation or extinction.
Threatened (T)
A wildlife species likely to become endangered if limiting factors are not reversed.
Special concern (SC)
(Note: Formerly described as “Vulnerable” from 1990 to 1999, or “Rare” prior to 1990.)
A wildlife species that may become a threatened or an endangered species because of a combination of biological characteristics and identified threats.
Not at risk (NAR)
(Note: Formerly described as “Not in any category”, or “No designation required.”)
A wildlife species that has been evaluated and found to be not at risk of extinction given the current circumstances.
Data deficient (DD)
(Note: Formerly described as “Indeterminate” from 1994 to 1999 or “ISIBD” [insufficient scientific information on which to base a designation] prior to 1994. Definition of the [DD] category revised in 2006.)
A category that applies when the available information is insufficient (a) to resolve a species’ eligibility for assessment or (b) to permit an assessment of the species’ risk of extinction.

The Canadian Wildlife Service, Environment and Climate Change Canada, provides full administrative and financial support to the COSEWIC Secretariat.

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