Caribou futures: migratory tundra caribou in a warmer world

A new report for WWF Global Arctic Programme assesses the vulnerability of caribou herds to climate change. The report found that all three examined herds are projected to decline under the best- and worst-case scenarios by 2100, but with large differences based on regional climate and vegetation. Based on the findings, the authors provide recommendations for how we can safeguard the futures of caribou.

Download the report (PDF, 3,8 MB)

Download the executive summary (PDF, 2 MB)

Explore our interactive infographics (PDF, 6,9 MB)

Understanding the future of caribou

Caribou are highly important to both Arctic ecosystems and Indigenous Peoples. From an ecological perspective, caribou for example help distribute nutrients over large area as they forage and migrate. They are also part of the food web and support several other species, including wolves, lynx and grizzly bears. For Indigenous Peoples, their relationships with caribou go back thousands of years. Caribou have provided the basis of life through meat and fat, skins for clothing, bedding and tents; sinew for sewing and antlers for tools. They still play a large role in Indigenous culture as well as spiritual beliefs and practices.

As the Arctic is projected to keep warming, we need to understand how caribou will be affected to find effective measures to safeguard the futures of the caribou herds and their role in the Arctic nature. In the report, “Caribou Futures: Assessing Vulnerability of Migratory Tundra Caribou to Climate Change”, caribou experts Don Russell and Anne Gunn used modelling to examine how different climate scenarios with different levels of warming will affect the three different herds.

How will climate change affect caribou?

A warmer climate brings several challenges to caribou, including heat stress and increasing insect harassment. This leads to caribou spending less time foraging. The body weight of the cows determines the likelihood of pregnancy. For the calves, their body weight influences their survival rates. Both of these factors influence how herd sizes change over time. In the best-case scenario, all three herds showed relatively little change until around 2050, followed by more substantial declines by 2100.

Examining three migratory tundra caribou herds

We have examined how three migratory herds, living in different regional climates and vegetation, will be affected by rising temperatures to help identify which herds are most vulnerable and in need of targeted management support. The three chosen herds were: the Bathurst herd, the Central Arctic herd and the Taimyr herd. Results of the modelling could broadly be extrapolated to other caribou herds with similar climate and environmental conditions.

Recommendations: what we can do to safeguard the futures of caribou

Keep landscapes open and connected and protect calving and summer ranges from disturbance

 Caribou rely heavily on their seasonal migrations and spatial memory to adapt to changing conditions. They can adjust their movements in response to seasonal and annual environmental variations, as long as their paths are not obstructed.

Ensure effective caribou herd management under climate change

Governments and co-management bodies collaborating can ensure that science and Indigenous Knowledge are used together and complementarily. This will provide the best-available information for herd management, based on herd characteristics, assessments incorporating climate change effects and providing an indication of risk of different harvest rates. Mitigation plans that are based on such proactive monitoring of herds could mitigate the impacts of the worst-case climate scenario.

Effectively limit greenhouse gas emissions

For all three herds, the models show that their adaptive capacity, as currently understood, will not be enough to mitigate the impacts of a high-warming future. Without effective limits on greenhouse gas emissions, some migratory tundra herds risk dwindling to small remnant populations or disappearing altogether.