Polar bears in Canada’s high Arctic are most vulnerable to climate change, research shows

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A report by researchers including from the University of Manitoba indicates that polar bears further north may be less able to adapt to climate warming.

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Published Wednesday in Ecology Letters, the report “Assessing the risk of climate maladaptation for Canadian polar bears” includes a map with hotspots of polar bear vulnerability and resilience across Canada, home to two-thirds of the world’s polar bears.

Researchers from leading institutions including Polar Bears International, Environment and Climate Change Canada, the San Diego Zoo Wildlife Alliance, the University of Manitoba, and MacEwan University have analyzed all of Canada’s polar bear populations and found that the most northern polar bears, those in Canada’s High Arctic, are less likely to be able to adapt to a rapidly warming Arctic.

With the Arctic warming up to four times faster than the rest of the planet, and polar bears reliant on sea ice to reach their seal prey, the authors find that many polar bears are genetically unsuited for future warming. This cutting-edge research represents a breakthrough in wildlife conservation technology, as pinpointing polar bears’ vulnerability will help guide conservation and management efforts.

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“This research is a first look at the genetics behind the vulnerability of polar bears in warming climates, and we found that while polar bears in the high Arctic face the most challenges to climate change, those at lower latitudes may be more robust to continued warming,” says lead author Dr. Ruth Rivkin, postdoctoral research fellow with Polar Bears International, University of Manitoba, and the San Diego Zoo Wildlife Alliance in a press release, adding “Our work analyzing the adaptive potential of polar bears is crucial, as it will continue to inform conservation efforts of polar bears that are most sensitive to climate change, and offers glimmers of hope in understanding which polar bears may be more resilient.”

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Key takeaways:
– High Arctic (>68 °N) polar bears (including parts of northern Nunavut and the Northwest Territories): These subpopulations have lower genetic diversity, which reduces their potential to adapt to climate change. The subpopulations with the largest genetic mismatch to climate change are Norwegian Bay, and M’Clintock Channel
– Low Arctic (55-68 °N) and sub-Arctic (&LT55 °N) polar bears (based in Ontario and Manitoba – including Churchill, the polar bear capital of the world): While polar bear populations in the Hudson Bay area have significantly declined, for example Western Hudson Bay’s polar bears decreased 27% between 2016-2021, they may be more genetically suited to climate change thanks to their extensive exposure to warm temperatures – whereas High Arctic bears haven’t experienced the same conditions.

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This will require further research, as will questions surrounding whether these polar bears can adapt quickly enough to match the rapid pace of Arctic warming, researchers said. The more genetically resilient subpopulations are Southern Hudson Bay, Western Hudson Bay, Foxe Basin, and Davis Strait. The researchers found five genetic clusters of polar bears. One cluster includes three subpopulations within Hudson Bay (Southern Hudson Bay, Western Hudson Bay, and Fox Basin), suggesting that the bears are moving around Hudson Bay and encountering each other.

“Our past emissions have committed the planet to ongoing warming in coming centuries. The extent to which populations might respond adaptively to warming is an open and important question for conserving biodiversity,” notes Dr. Colin Garroway, co-author and Associate Professor at the University of Manitoba, adding, “Forecasting where environments will cause the most evolutionary pressure for multiple warming scenarios will help guide management and understand ecological change in the Arctic.”

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“Climate change is putting enormous pressure on species across the globe, perhaps nowhere more so than in the Arctic,” says Dr. Aryn Wilder, co-author and Scientist in Conservation Genetics at the San Diego Zoo Wildlife Alliance, “Genomic approaches like these are becoming increasingly important for identifying populations that may need conservation intervention, such as additional protections or genetic rescue, to ease pressure and facilitate adaptation to their
changing environment.

This study uses genetic data and machine learning to predict how polar bears will need to evolve under climate change, offering a future look to inform conservation, management, and policy-making organizations. The study looked at 13 of the world’s 20 polar bear subpopulations, analyzing 411 samples in total.

glen.dawkins@kleinmedia.ca

X: @SunGlenDawkins

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