Polar Biology

, Volume 41, Issue 5, pp 953–967 | Cite as

Impacts of climate-driven habitat change on the peak calving date of the Bathurst caribou in Arctic Canada

  • Wenjun Chen
  • Jan Z. Adamczewski
  • Lori White
  • Bruno Croft
  • Anne Gunn
  • Adeline Football
  • Sylvain G. Leblanc
  • Donald E. Russell
  • Boyan Tracz
Original paper


Since mid-1980’s, the population of the Bathurst barren ground caribou (Rangifer tarandus) in Canada’s Arctic has declined by 93%. In order to develop and implement an effective recovery plan, it is important to know how various factors have cumulatively impacted the population decline. To contribute to the knowledge, we investigated the following two questions: how have changes in climate-induced habitat conditions impacted the peak calving date of the Bathurst caribou, and what was the implication of the impact on the population? Our results indicate that the peak calving date was impacted by changes in habitat conditions (e.g., the start date of vegetation growing season SOS) in a complex manner. Large inter-annual variations in SOS on the calving ground and summer range of the Bathurst herd were observed during 1985 and 2012, with the largest difference being 29 days. A 1-day delay of SOS in year i − 1 on the calving ground (SOScg(i − 1)) from its normal date could result in a 0.5-day delay in the peak calving date in year i, likely caused by the delay in the conception date in the previous fall. However, advances in SOScg(i − 1) did not alter the peak calving date in year i. Furthermore, a 1-day delay (or advance) in the current year’s SOS on the summer range (SOSsr(i)) might cause a 0.23-day delay (or advance) in the peak calving date in the current year, likely through changing the caribou’s gestation duration. Together SOScg(i − 1) and SOSsr(i) explained 69.1% of the variation in the peak calving date of the Bathurst caribou herd during 1985–2012, indicating the cumulative impacts on the peak calving date by the changing habitat conditions over a period of 2 years and thus the validation of the cumulative habitat impact hypothesis. Finally, our results also show that a 1-day delay in the peak calving date corresponded approximately 2–3% reduction in the birth rate of the Bathurst caribou, and thus might have been partially responsible for the population decline.


Bathurst caribou Vegetation Phenology Calving date Remote sensing 



Roy Judas and Brain Kodzin (Wekweeti), and Claire Elliott and Elyn Humphreys (Carleton University) participated in the community-based vegetation monitoring in 2013 and 2014. Bonnie Fournier and Adrian D’Hont from Environment and Natural Resources of GNWT provided the collared cow GPS data and range map. Rasim Latifovic, Fuqun Zhou, Richard Fernandes, and Ian Olthof of CCRS provided the 10-day AVHRR composites, snow cover, and land cover data. The guidance, suggestions, and technical assistance from Government of NWT, Tlicho Government, Wek’èezhìi Renewable Resources Board, and CircumArctic Rangifer Monitoring and Assessment Network (CARMA) are much appreciated. We are grateful for the comments made by anonymous reviewers, which have significantly strengthened the manuscript.


The study is funded by the NWT Cumulative Impact Monitoring Program (CIMP) of the Government of Northwest Territories and the Remote Sensing Science Program of Natural Resources Canada.

Compliance with ethical standards

Conflict of interest

The authors declare that they have no conflict of interest.

Ethical approval

All applicable international, national, and institutional guidelines for the care and use of animals were followed.


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Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2018

Authors and Affiliations

  • Wenjun Chen
    • 1
  • Jan Z. Adamczewski
    • 2
  • Lori White
    • 1
    • 7
  • Bruno Croft
    • 2
  • Anne Gunn
    • 3
  • Adeline Football
    • 4
  • Sylvain G. Leblanc
    • 1
  • Donald E. Russell
    • 5
  • Boyan Tracz
    • 6
  1. 1.Canada Centre for Remote SensingNatural Resources CanadaOttawaCanada
  2. 2.Environment and Natural ResourcesGovernment of the Northwest TerritoriesYellowknifeCanada
  3. 3.Salt Spring IslandCanada
  4. 4.Tlicho GovernmentWekweetiCanada
  5. 5.Yukon CollegeWhitehorseCanada
  6. 6.Wek’èezhìi Renewable Resources BoardYellowknifeCanada
  7. 7.National Wildlife Research CentreEnvironment CanadaOttawaCanada

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