16.3 Status of Peary Caribou in a changing climate

Last Updated: 
November 12, 2015

This indicator reports on the status of Peary caribou, a key species at risk, in NWT Arctic ecosystems. It also tracks changes in muskox populations, the only other large herbivore sharing the Peary caribou range. This indicator sheds light on the low carrying capacity of the NWT’s most northern ecosystems and the potential effects of changing climate on the recovery of a subspecies of caribou at risk of extinction.

Peary caribou and muskox population estimates are measured using multi-species aerial surveys performed at irregular intervals by ENR, GNWT.

NWT Focus

Peary caribou exist only in Canada and about 40-60% of the population is in the NWT. Peary caribou was assessed as endangered in Canada in 20041 and threatened in the NWT in 20122. Hunting Peary caribou is permitted on Banks Island under a quota system. A zero harvest on Peary caribou on NW Victoria Island was initiated in 1993. It is reviewed annually.

Muskoxen were intensively hunted until, by the 1930s, there were very few herds remaining in the barrenlands and some Arctic islands. At one time considered to be on the brink of extinction, muskoxen are no longer considered at risk of extirpation. Their numbers are increasing most rapidly on the mainland NWT and Nunavut3. Muskoxen are hunted in the NWT and there is an average commercial harvest of 342 muskoxen per year (range 0-1,450, between 1998 and 2008) on Banks Island4,5.

Current view: status and trend

The High Arctic - Western Queen Elizabeth Islands - Prince Patrick, Melville, and adjacent islands

In 1961, a survey showed the Western High Arctic Islands had about 5,000 muskoxen and 24,000 Peary caribou6. In the winter of 1973/74 and then again in the winters of 1993/94 and 1994/95, large numbers of both species died off. Many carcasses of both Peary caribou and muskoxen were observed during these winters and there was evidence of increased movements of animals between islands in search of a better range. There is evidence of at least some recovery between 1976 and 1993 on Bathurst Island. No surveys were conducted on Prince Patrick and Melville Islands between 1988 and 1996 but signs of recovery followed by die-offs on these islands suggest it is likely the same events affected all the High Arctic Islands. Evidence points to higher than normal snow cover and/or icing during winter as the cause of these large declines. To obtain food in winter, caribou and muskoxen must dig or paw down to the vegetation under the snow. This is easier in areas where wind has removed most of the snow and in years of less snow. Rain in the fall can create ground-fast ice that restricts the availability of the animals to reach forage later in the winter. Years with the highest recorded snowfall (at Resolute Weather station) also showed die-offs: the winter of 1973/74; and, the three consecutive winters of 1994/95, 1995/96 and 1996/97.

There is evidence that muskox and Peary caribou populations can recover if warm, snowy winters occur only rarely. Consecutive winters with late rain or high levels of snowfall are especially difficult for populations of the only two species of large herbivores adapted to live on the High Arctic islands. The impact of future harsh winters on Peary caribou and muskox populations on the High Arctic islands is unknown. However, results from the latest surveys on northwestern Queen Elizabeth Islands in 2012 are encouraging as more Peary caribou were seen and new areas were occupied than in the past decade2.

Peary caribou population
Peary caribou population in the NWT Markers represent years with survey data. Error bars +1 SE. Lines between markers are not indicative of trends between survey years but only serve to visualize overall trends over many years and surveys for each island. Source: Peary caribou data: SARC Report 2012.

Muskox populations
Muskox on northern islands in the NWT. Muskox populations also exist on the mainland, but data not shown. Error bars = 1 SE. Markers represent years with survey data. Lines between markers are not indicative of trends between survey years but only serve to visualize overall trends over many years and surveys for each island. Source: Muskox data: Fournier, B, and A. Gunn. 1997. Muskox Numbers and Distribution in the Northwest Territories, 1997. ENR File Report 121. 55pp., Gunn, A. and J. Dragon. 2000. Peary Caribou and Muskox Abundance and Distribution on the Western Queen Elizabeth Islands, Northwest Territories and Nunavut June-July 1997. ENR File Report 130. 87pp., Davison and Williams 2012. Preliminary Results Summary.

Banks Island

Surveys in 1972 showed  3,800 muskoxen and 12,098 Peary caribou  present on the island7. Unlike other islands, surveys have been conducted more regularly and, in a more systematic fashion, on Banks Island8. Surveys showed by 1994, muskoxen had increased to about 64,000 and Peary caribou numbers had decreased to about 800. More recently, muskox numbers have declined and the number of Peary caribou has increased slightly again. Banks Island is relatively lush compared to the Queen Elizabeth islands and it's climate is milder. As on islands further north, unusually mild and wet winters, especially with freezing rain, have resulted in die-offs and lower calf production for muskox and, more notably, Peary caribou in some years. The ecology of both species on Banks Island is still being studied. A combination of factors may explain the low recovery of caribou numbers after low survival winters, including competition with muskoxen for food or feeding areas, increased predation pressure and movement of caribou off the island. Caribou hunting is allowed under such a low quota that it may not be a significant pressure. Little weather data is available for Banks Island, making it difficult to track the effects of mild snowy winters and rain or snow events on large herbivores on the island9. Climate models and satellite data showed a severe rainfall event in October 200310, which resulted in a die-off of about half of the muskox population on the island.

Looking forward

A slight increase in numbers of Peary caribou observed during the last survey on Banks, Melville and other northern islands signals some recovery of these populations at present. Warmer and snowier winters have occurred more often in the High Arctic in the past two decades than before. If such warm winters become the norm,  prospects for a full recovery of populations of the endangered Peary caribou on NWT’s northern-most islands appear slim11. The possibility of Peary caribou disappearing from many northern-most islands in the High Arctic is still high.

Muskox populations may abandon the High Arctic islands for better forage areas in a more southern range in the Southern Arctic. Muskox populations on the mainland in the NWT are variable12. Despite population declines, especially in the northern-most part of their range, muskoxen populations have shown great capacity to recover quickly.

Looking around

Peary caribou and muskoxen also occur in Nunavut. Similar weather effects, interactions between the two species, and movements between islands have also been noted on Nunavut’s High Arctic Islands1.

Find out more

  • To find more on Peary caribou and muskox ecology visit the ENR website.
  • On species at risk such as Peary Caribou visit the COSEWIC website.

Other focal points

Technical Notes

  • More information on trends in calf/cow ratio, survival rates, food and habitat selection of both species can be found in references below.

 

Found an error or have a question? Contact the team at NWTSOER@gov.nt.ca.


Reference List

Ref 1 - COSEWIC.  2004. Peary Caribou. 

Ref 2 - SARC. 2012. Species status report on Peary Caribou in the NWT. ENR,

Ref 3 - ENR Webpage.  2007. Muskox. GNWT.

Ref 4 - Nagy J. A., Larter N.C., Fraser V.P. 1996. Population demography of Peary caribou and muskox on Banks Island, NWT, 1983-1992. Rangifer 16 (4):213-222.

Ref 5 - Governmetn of the Northwest Territories. 2008. Summary of Harvest Data for Species Under Quota in the Invuialuit Settlement Region:  July 2003 to June 2008. Government of the Northwest Territories. DENR. Invuik Region.

Ref 6 - Miller F. L., Gunn A., 2003. Status, population fluctations and ecological relationships of Peary caribou on the Queen Elizabeth Islands: Implications for their survival. Rangifer 14:213-226.

Ref 7 - Harding L.E., 2004. Update COSEWIC Status Report of Peary Caribou Rangifer tarandus pearyi in Canada, Ottawa, ON.

Ref 8 - Nagy J. A., Larter N. C., Fraser V. P. 1996. Population demography of Peary caribou and muskox on Banks Island, N.W.T., 1982-1992. Rangifer 16(4):213-222

Ref 9 - Environment Canada.  2004. Resolute CARS Historical Weather.EC, Canada.

Ref 10 - Grenfell T. C., Putkonen J.2008. A method for the detection of the severe rain-on-snow event on Banks Island, October 2003, using passive microwave remote sensing. Water Resources Research 44:W03425

Ref 11 - Miller F. L., Gunn A.2003. Status, population fluctuations and ecological relationships of Peary caribou on the Queen Elizabeth Islands: Implications for their survival. Rangifer 213-226

Ref 12 - Veitch A. M. 1997. An Aerial Survey For Muskoxen In The Northern Sahtu Settlement Area, March 1997. Manuscript Report 103, GNWT – ENR.