Caribou (Rangifer tarandus) COSEWIC assessment and status report 2014: chapter 1

Common name

Caribou - Northern Mountain population

Scientific name

Rangifer tarandus

Status

Special Concern

Reason for designation

This population occurs in 45 subpopulations ranging from west-central British Columbia to the Yukon and western Northwest Territories. Almost all of its distribution is in Canada, where it numbers about 43,000 - 48,000 mature individuals. There is little long-term (three generations) trend information, and many current estimates are based on survey data more than 5 years old. Currently 2 subpopulations are thought to be increasing, 7 are stable and 9 are declining. The condition of the remaining 27 subpopulations is unknown. The two largest subpopulations comprise > 15,000 animals, or 26-29% of the estimated population, and are thought to be stable. About half of the 45 subpopulations each contain < 500 individuals. All stable or increasing subpopulations are located in the northern part of the range, whereas 9 in the southern part of the range have declined by 27% since the last assessment. The status of northern subpopulations may be compromised in the future because of increasing threats, particularly land use change with industrial development causing shifts in predator-prey dynamics.

Occurrence

Yukon, Northwest Territories, British Columbia

Status history

The Northern Mountain population was designated Not at Risk in May 2000. This population was formerly designated as part of the “Western population”(now de-activated). Status re-examined and designated Special Concern in May 2002. Following the Designatable Unit report on caribou (COSEWIC 2011), a new population structure was proposed and accepted by COSEWIC. This new Northern Mountain population is composed of all 36 subpopulations in the previous Northern Mountain population of Caribou in addition to 9 subpopulations from the previous (2002) Southern Mountain population. The Northern Mountain population was designated Special Concern in May 2014.

Common name

Caribou - Central Mountain population

Scientific name

Rangifer tarandus

Status

Endangered

Reason for designation

This population is endemic to Canada and occurs in 10 extant subpopulations in east-central British Columbia and west-central Alberta in and around the Rocky Mountains. The current estimate for the population is 469 mature individuals and it has declined by at least 64% over the past 3 generations. One subpopulation in central British Columbia was confirmed extirpated in 2014, and an additional one in Banff in 2010. All extant subpopulations are estimated to contain fewer than 250 mature individuals, with 4 of these having fewer than 50. Two recognized subpopulations in 2002 have since split due to lack of dispersal within former ranges. All subpopulations have experienced declines of about 60% since the last assessment in 2002, and declines continue for all but one subpopulation, which has an unknown trend. Surveys have shown consistently high adult mortality and low calf recruitment, accelerating decline rates. Threats are continuing and escalating.

Occurrence

British Columbia, Alberta

Status history

Following the Designatable Unit report on caribou (COSEWIC 2011), a new population structure was proposed and accepted by COSEWIC. This resulted in the new Central Mountain population, composed of 12 subpopulations from the previous Southern Mountain population of Caribou (COSEWIC 2002). The Central Mountain population was designated Endangered in May 2014.

Common name

Caribou - Southern Mountain population

Scientific name

Rangifer tarandus

Status

Endangered

Reason for designation

This population is largely restricted to Canada, except for < 40 animals in Idaho and Washington. It occurs in 15 extant subpopulations in southeastern British Columbia. Two subpopulations have been extirpated since 2002. The current estimate for the population is 1,356 mature individuals, which has declined by at least 45% in the past three generations, and 27% since the last assessment in 2002. All but two extant subpopulations are estimated to contain fewer than 250 mature individuals, with 9 of these having fewer than 50, and 6 with fewer than 15 mature individuals. Dispersal within the ranges of 11 subpopulations is severely limited. Surveys have shown consistently high adult mortality and low calf recruitment, accelerating decline rates. Threats are continuing and escalating.

Occurrence

British Columbia

Status history

The Southern Mountain population was designated Threatened in May 2000. This population was formerly designated as part of the “Western population” (now deactivated). Status re-examined and confirmed in May 2002. Following the Designatable Unit report on Caribou (COSEWIC 2011), a new population structure was proposed and accepted by COSEWIC. This resulted in the new Southern Mountain population, composed of 17 subpopulations from the former Southern Mountain population of Caribou (COSEWIC 2002). The remaining subpopulations were assigned to the new Central and Northern Mountain populations.The Southern Mountain population was designated Endangered in May 2014.

Generation time
(calculated using IUCN formula)

9 year

Is there an [observed, inferred, or projected] continuing decline in number of mature individuals?
(Trend is known for 18 of 45 subpopulations representing approximately 54% of the current population; 9 are declining, mostly in the southern portion of the DU (including all 5 west-central BC subpopulations), and 2 are known to be increasing; 6 of 10 subpopulations with ≥3 years of late winter recruitment data have calf recruitment <15%)

Overall trend is unknown

Estimated percent of continuing decline in total number of mature individuals within [5 years or 2 generations]
(See above)

Overall trend is unknown

[Observed, estimated, inferred, or suspected] percent [reduction or increase] in total number of mature individuals over the last [10 years, or 3 generation].
(See above)

Overall trend is unknown

[Projected or suspected] percent [reduction or increase] in total number of mature individuals over the next [10 years, or 3 generations].
(See above. Subpopulations that are declining will likely continue to decline. However, fluctuations in the number of caribou in large subpopulations in the northern portion of the DU or refined population estimates for those subpopulations could mask declines of smaller subpopulations when considering the total number of caribou in the DU)

Overall trend is unknown

[Observed, estimated, inferred, or suspected] percent [reduction or increase] in total number of mature individuals over any [10 years, or 3 generations] period, over a time period including both the past and the future.
(See above)

Overall trend is unknown

Are the causes of the decline clearly reversible and understood and ceased?
(Causes of decline known for 9 declining subpopulations, but declines are not ceased and are not clearly reversible)

N/A Trend unknown for most of the 45 subpopulations

Are there extreme fluctuations in number of mature individuals?

No

Estimated extent of occurrence

1,050,174 km²

Index of area of occupancy (IAO)

523,672 km²

Is the population severely fragmented?

No

Number of locations ^{Extent and Occupancy Information Footnote1}
(Diverse threats across range)

N/A

Is there an inferred continuing decline in extent of occurrence?

No

Is there an [observed, inferred, or projected] continuing decline in index of area of occupancy?
(9 populations are known to be declining, leading to a reduction in density, but not total distribution)

Not likely

Is there an [observed, inferred, or projected] continuing decline in number of populations?
(some subpopulations have declined to low levels but no subpopulations have yet been extirpated in this DU; as more information is collected on distribution and movements of subpopulations, further refinement of subpopulation boundaries may result in a recalibration of the number of subpopulations)

No

Is there an [observed, inferred, or projected] continuing decline in number of locations ^{Extent and Occupancy Information Footnote1}?

N/A

Is there an observed continuing decline in and/or quality of habitat?
(in the southern portion of the DU and in more accessible ranges in the northern portion of the DU, industrial and other human activities resulting in habitat change favouring other prey species, and/or disturbance to caribou are continuing)

Yes

Are there extreme fluctuations in number of populations?

No

Are there extreme fluctuations in number of locations ^{Extent and Occupancy Information Footnote1}?

N/A

Are there extreme fluctuations in extent of occurrence?

No

Are there extreme fluctuations in index of area of occupancy?

No

Probability of extinction in the wild is at least [20% within 20 years or 5 generations, or 10% within 100 years].
(Population viability analyses [PVAs] are available for only 2 subpopulations, both in west-central BC. The PVA for the Tweedsmuir subpopulation predicts that the population will decrease by at least 50% in 20 years and the model for the Itcha-Ilgachuz PVA also predicts a decline)

N/A

Altered predator-prey dynamics due to habitat change, human disturbance/habitat loss as a result of forest harvesting, mineral exploration and development and associated access, changes in habitat structure following Mountain Pine Beetle infestations and/or associated salvage logging, and motorized and non-motorized recreational activities.

Status of outside population(s)?
Interior Alaska subpopulations have not been assessed with respect to COSEWIC designatable units

Ranked as secure in Alaska, but many subpopulations are declining

Is immigration known or possible?

Yes

Would immigrants be adapted to survive in Canada?

Yes

Is there sufficient habitat for immigrants in Canada?

Yes, in the northern part of the DU

Is rescue from outside populations likely?
(Possibly from Alaska but the subpopulations there have not been assessed with respect to COSEWIC designatable units)

Possibly from Alaska

Is this a data-sensitive species?

No

COSEWIC:

The Northern Mountain population was designated Not at Risk in May 2000. This population was formerly designated as part of the “Western population”(now deactivated). Status re-examined and designated Special Concern in May 2002. Following the Designatable Unit report on Caribou (COSEWIC 2011), a new population structure was proposed and accepted by COSEWIC. This new Northern Mountain population is composed of all 36 subpopulations in the previous Northern Mountain population of Caribou in addition to 9 subpopulations from the previous (2002) Southern Mountain population. The Northern Mountain population was designated Special Concern in May 2014.

Status:

Special Concern

Alpha-numeric code:

Not applicable

Reason for Designation:

This population occurs in 45 subpopulations ranging from west-central British Columbia to Yukon and western Northwest Territories. Almost all of its distribution is in Canada, where it numbers about 43,000 - 48,000 mature individuals. There is little long-term (three generations) trend information, and many current estimates are based on survey data more than 5 years old. Currently 2 subpopulations are thought to be increasing, 7 are stable and 9 are declining. The condition of the remaining 27 subpopulations is unknown. The two largest subpopulations comprise > 15,000 animals, or 26-29% of the estimated population, and are thought to be stable. About half of the 45 subpopulations each contain < 500 individuals. All stable or increasing subpopulations are located in the northern part of the range, whereas 9 in the southern part of the range have declined by 27% since the last assessment. The status of northern subpopulations may be compromised in the future because of increasing threats, particularly land use change with industrial development causing shifts in predator-prey dynamics.

Criterion A (Decline in Total Number of Mature Individuals):

Unknown. Evidence for declines in some subpopulations, but overall trend unknown.

Criterion B (Small Distribution Range and Decline or Fluctuation):

Not applicable. EO and IAO exceed thresholds.

Criterion C (Small and Declining Number of Mature Individuals):

Not applicable. Population exceeds 10,000 mature individuals.

Criterion D (Very Small or Restricted Population):

Not applicable. Population exceeds 1,000 mature individuals, and IAO and number of locations exceeds thresholds.

Criterion E (Quantitative Analysis):

Not applicable.

Generation time
(calculated using IUCN formula)

9 yrs

Is there an [observed, inferred, or projected] continuing decline in number of mature individuals?

Yes

Estimated percent of continuing decline in total number of mature individuals within [5 years or 2 generations]
(based on the rate of decline for the past 2 generations). The decline rate is likely an underestimate, as the early surveys on which the decline was based for some subpopulations was more recent than 2 generations ago)

At least 62%

[Observed, estimated, inferred, or suspected] percent [reduction or increase] in total number of mature individuals over the last [10 years, or 3 generation].
(9 of 10 extant subpopulations are declining, one of which may be extirpated, and the trend for the other is unknown. Two additional subpopulations have been confirmed extirpated. The decline rate is likely an underestimate, as the early surveys on which the decline was based for some subpopulations was > 3 generations ago)

At least 64%

[Projected or suspected] percent [reduction or increase] in total number of mature individuals over the next [10 years, or 3 generations].
(based on the rate of decline for the past 3 generations)

At least 64%

[Observed, estimated, inferred, or suspected] percent [reduction or increase] in total number of mature individuals over any [10 years, or 3 generations] period, over a time period including both the past and the future.
(based on the rate of decline for the past 3 generations)

At least 64%

Are the causes of the decline clearly reversible and understood and ceased?
(Although the cause of the decline for most subpopulations has been attributed to altered predator-prey dynamics due to extensive habitat change from industrial activities, there may be additional contributing factors that are not well-understood; recovery of habitat will take decades and industrial activities are continuing and expanding. Subpopulations with lower levels of disturbance are also declining. Habitat destruction from industrial activities is ongoing and becoming more widespread).

Reversible: Unknown;Understood: Incomplete;Ceased: No

Are there extreme fluctuations in number of mature individuals?
Does not meet IUCN definition of extreme fluctuations

No

Estimated extent of occurrence

85,986 km²

Index of area of occupancy (IAO)

46,144 km²

Is the population severely fragmented?

Yes

Number of locations ^{Extent and Occupancy Information Footnote2}

N/A

Is there an inferred continuing decline in extent of occurrence?
(2 subpopulations have been extirpated since the previous status report in 2002 and the Bearhole/Redwillow portion of the Narraway subpopulation is considered to no longer occur in Alberta. EO cannot be directly compared with that of previous assessment due to change in DU boundaries)

Likely

Is there an [observed, inferred, or projected] continuing decline in index of area of occupancy?
(2 subpopulations have been extirpated since the previous status report in 2002. IAO cannot be directly compared with that of previous assessment due to change in DU boundaries)

Likely

Is there an [observed, inferred, or projected] continuing decline in number of populations?
(2 subpopulations have been extirpated since the previous status report in 2002)

Yes

Is there an [observed, inferred, or projected] continuing decline in number of locations ^{Extent and Occupancy Information Footnote2}?

N/A

Is there an observed continuing decline in and/or quality of habitat?
(industrial and other human activities resulting in habitat change favouring other prey species, and/or disturbance to caribou is continuing; a recent analysis of habitat change for east-central BC subpopulations reported loss of very high and high quality winter habitat from 0 to 66% [Williamson-Ehlers et al. 2013]).

Yes

Are there extreme fluctuations in number of populations?

No

Are there extreme fluctuations in number of locations ^{Extent and Occupancy Information Footnote2}?

N/A

Are there extreme fluctuations in extent of occurrence?

No

Are there extreme fluctuations in index of area of occupancy?

No

Probability of extinction in the wild is at least [20% within 20 years or 5 generations, or 10% within 100 years].
(PVAs were conducted on 10 subpopulations in three studies, but probability of extinction was not calculated for all)

None available.

Altered predator-prey dynamics due to habitat change resulting from forest harvesting and forest harvesting in combination with oil and gas exploration and development; human disturbance and other habitat loss due to multiple industrial activities including forest harvesting, coal exploration and development, and oil and gas exploration and development. Other factors include vehicle collisions, motorized recreation (ATV, snowmobiling), facilitated access for predators, small population effects, and infectious diseases that are likely to have increasing negative impacts in a changing climate.

Status of outside population(s)?
Endemic to Canada

N/A

Is immigration known or possible?

No

Would immigrants be adapted to survive in Canada?

N/A

Is there sufficient habitat for immigrants in Canada?

N/A

Is rescue from outside populations likely?

No

Is this a data-sensitive species?

No

COSEWIC:

Following the Designatable Unit report on caribou (COSEWIC 2011), a new population structure was proposed and accepted by COSEWIC. This resulted in the new Central Mountain population, composed of 12 subpopulations from the previous Southern Mountain population of Caribou (COSEWIC 2002). The Central Mountain population was designated Endangered in May 2014.

Status:

Endangered

Alpha-numeric code:

A2a+3a+4a; C1+C2a(i)

Reason for Designation:

This population is endemic to Canada and occurs in 10 extant subpopulations in east-central British Columbia and west-central Alberta in and around the Rocky Mountains. The current estimate for the population is 469 mature individuals and it has declined by at least 64% over the past 3 generations. One subpopulation in central British Columbia was confirmed extirpated in 2014, and an additional one in Banff in 2010. All extant subpopulations are estimated to contain fewer than 250 mature individuals, with 4 of these having fewer than 50. Two recognized subpopulations in 2002 have since split due to lack of dispersal within former ranges. All subpopulations have experienced declines of about 60% since the last assessment in 2002, and declines continue for all but one subpopulation, which has an unknown trend. Surveys have shown consistently high adult mortality and low calf recruitment, accelerating decline rates. Threats are continuing and escalating.

Criterion A (Decline in Total Number of Mature Individuals):

Meets EN A2a+3a+4a.
Meets Endangered A2a with overall decline (at least 64%) exceeding 50%. Causes have not ceased and may not be reversible. Trend calculated based on a) direct observation. Meets Endangered A3a due to inferred reduction of greater than 50% in the next 3 generations based on ongoing decline trends. Trend calculated based on a) direct observation. Meets Endangered A4a due to suspected inferred reduction of greater than 50% based on impact within a 3-generation period in the past or into the future. Trend calculated based on a) direct observation. A1 is not applicable because the causes of the decline have not ceased.

Criterion B (Small Distribution Range and Decline or Fluctuation):

Not applicable. EO and IAO both exceed thresholds.

Criterion C (Small and Declining Number of Mature Individuals):

Meets Endangered C1+2a(i). Meets Endangered C1 as population numbers fewer than 2,500 and is experiencing an estimated continuing 2-generation decline of greater than 62% (exceeds 20% threshold). Meets Endangered C2a(i) as there is a continuing decline in number of mature individuals and no subpopulation is estimated to contain more than 250 individuals.

Criterion D (Very Small or Restricted Population):

Meets Threatened D1 as population fewer than 1,000 mature individuals. D2 is not applicable as IAO and the number of locations exceed thresholds.

Criterion E (Quantitative Analysis):

Not applicable. Three PVAs were conducted on most subpopulations but probability of extinction was not predicted for all.

Generation time
(calculated using IUCN formula)

9 yrs

Is there an [observed, inferred, or projected] continuing decline in number of mature individuals?

Yes

Estimated percent of continuing decline in total number of mature individuals within [5 years or 2 generations]
(based on the rate of decline for the past 2 generations. The decline rate may be underestimated as the early survey upon which the decline was based for some subpopulations was more recent than 2 generations ago)

At least 40%

[Observed, estimated, inferred, or suspected] percent [reduction or increase] in total number of mature individuals over the last [10 years, or 3 generation].
(14/15 subpopulations have declined over the last 3 generations, and 2 have been extirpated. Only 1 is known to be increasing and that subpopulation currently consists of only 78 mature individuals. The decline rate may be underestimated as the early survey upon which the decline was based for some subpopulations was more recent than 3 generations ago)

At least 45%

[Projected or suspected] percent [reduction or increase] in total number of mature individuals over the next [10 years, or 3 generations].
(based on the rate of decline for the past 3 generations)

At least 45%

[Observed, estimated, inferred, or suspected] percent [reduction or increase] in total number of mature individuals over any [10 years, or 3 generations] period, over a time period including both the past and the future.
(based on the rate of decline for the past 3 generations)

At least 45%

Are the causes of the decline clearly reversible and understood and ceased?
(Although the cause of the decline has been attributed to altered predator-prey dynamics due to habitat change resulting from forest harvesting in adjacent valley bottoms, there may be additional contributing factors that are not well-understood; recovery of habitat will take decades and industrial activities are continuing and expanding)

Reversible: Unknown Understood: Incomplete Ceased: No

Are there extreme fluctuations in number of mature individuals?

No

Estimated extent of occurrence

118,2401 km²

Index of area of occupancy (IAO)

46,324 km²

Is the population severely fragmented?

No

Number of locations ^{Extent and Occupancy Information Footnote3}
(diverse threats across range)

N/A

Is there an inferred continuing decline in extent of occurrence?
(2 subpopulations have been extirpated since the previous status report in 2002; EO cannot be directly compared with that of previous assessment due to change in DU boundaries)

Yes

Is there an [observed, inferred, or projected] continuing decline in index of area of occupancy?
(2 subpopulations have been extirpated since the previous status report in 2002. IAO cannot be directly compared with that of previous assessment due to change in DU boundaries)

Yes

Is there an [observed, inferred, or projected] continuing decline in number of populations?
(2 subpopulations have been extirpated since the previous status report in 2002)

Yes

Is there an [observed, inferred, or projected] continuing decline in number of locations ^{Extent and Occupancy Information Footnote3}?

N/A

Is there an observed continuing decline in and/or quality of habitat?

Yes

Are there extreme fluctuations in number of populations?

No

Are there extreme fluctuations in number of locations ^{Extent and Occupancy Information Footnote3}?

N/A

Are there extreme fluctuations in extent of occurrence?

No

Are there extreme fluctuations in index of area of occupancy?

No

Probability of extinction in the wild is at least [20% within 20 years or 5 generations, or 10% within 100 years].
(2 PVAs have been conducted on subpopulations within the Southern Mountain DU: one was based on vital rates [Wittmer et al. 2010], and one on population estimates from surveys [Hatter 2006]. Wittmer et al. [2010] found that 8/10 had probabilities >20% within 45 yrs (5 generations) and Hatter [2006] predicted quasi-extinction [<20 animals] in 20 years was >20% for 13 of 15 subpopulations)

Yes

Altered predator/prey dynamics due to habitat change resulting from forest harvesting in adjacent low elevation valley bottoms, and from increased predator efficiency using trails created by snowmobiling and heli-skiing. Infectious diseases are likely to cause increasing negative impacts, particularly in a changing climate.

Status of outside population(s)?

Endangered in Idaho and Washington

Is immigration known or possible?

No

Would immigrants be adapted to survive in Canada?

Possibly

Is there sufficient habitat for immigrants in Canada?

N/A

Is rescue from outside populations likely?

No

Is this a data-sensitive species?

No

COSEWIC:

The Southern Mountain population was designated Threatened in May 2000. This population was formerly designated as part of the “Western population” (now deactivated). Status re-examined and confirmed in May 2002. Following the Designatable Unit report on Caribou (COSEWIC 2011), a new population structure was proposed and accepted by COSEWIC. This resulted in the new Southern Mountain population, composed of 17 subpopulations from the former Southern Mountain population (COSEWIC 2002). The remaining subpopulations were assigned to the new Central and Northern Mountain populations.The Southern Mountain population was designated Endangered in May 2014.

Status:

Endangered

Alpha-numeric code:

A3a+4a; C1

Reason for Designation:

This population is largely restricted to Canada, except for < 40 animals in Idaho and Washington. It occurs in 15 extant subpopulations in southeastern British Columbia. Two subpopulations have been extirpated since 2002. The current estimate for the population is 1,356 mature individuals, which has declined by at least 45% in the past three generations, and 27% since the last assessment in 2002. All but two extant subpopulations are estimated to contain fewer than 250 mature individuals, with 9 of these having fewer than 50, and 6 with fewer than 15 mature individuals. Dispersal within the ranges of 11 subpopulations is severely limited. Surveys have shown consistently high adult mortality and low calf recruitment, accelerating decline rates. Threats are continuing and escalating.

Criterion A (Decline in Total Number of Mature Individuals):

Meets Endangered A3a based on inferred reduction of >50% in the next 3 generations based on ongoing decline trends. Trend calculated based on a) direct observation.
Meets Endangered A4a based on suspected inferred reduction of >50% based on impact within a 3-generation period in the past or into the future. Trend calculated based on a) direct observation.
Meets Threatened A2a with overall decline (at least 45%) exceeding 30%. Causes have not ceased and may not be reversible. Trend calculated based on a) direct observation.
A1 is not applicable as causes of decline have not ceased.

Criterion B (Small Distribution Range and Decline or Fluctuation):

Not applicable. EO and IAO both exceed thresholds.

Criterion C (Small and Declining Number of Mature Individuals):

Meets Endangered C1 as population contains < 2,500 mature individuals and shows a 2-generation decline of >40% (exceeds 20% threshold).
Meets Threatened C2a(i). There is a continuing decline and all subpopulations estimated to contain < 1000 mature individuals (all but two < 250, almost meeting Endangered).

Criterion D (Very Small or Restricted Population):

D1 is not applicable. Population > 1,000 individuals.
D2 is not applicable. IAO and # locations exceed thresholds.

Criterion E (Quantitative Analysis):

Meets Endangered E. Two PVAs conducted on 10/15 and 15/15 extant subpopulations respectively, predicted extinction risk > 20% in approximately 45 years (5 generations) for 13.