Polar bears barely adapting to climate change
As polar bears struggle with multiple accelerating challenges in a rapidly warming Arctic, scientists have now pulled together the first comprehensive review of what we know about how the species is responding evolutionarily to these changes.
Although genetic variation is essential for adapting to shifting environmental conditions, the review finds that this capacity is becoming more constrained in some — but not all — populations of polar bears. Shrinking sea ice is making it harder for bears to hunt and interact with each other, interfering with normal population mixing and, in some regions, leading to signs of significant inbreeding. Climate change, along with subsistence hunting and other human pressures, may also be causing bears to become smaller, a typical response to warmer conditions and more unpredictable food supplies. Despite these changes, however, scientists have detected little evidence of true physiological adaptation; instead, bears appear to be coping primarily by altering their behavior, such as hunting for new kinds of prey.
By bringing together scattered genetic and ecological studies, the review highlights an urgent need to integrate these data streams to improve monitoring and protection of wide-ranging animals like polar bears, especially in regions of the world where climate change is already causing significant upheaval.
Read the article in Ecological Monographs: https://esajournals.onlinelibrary.wiley.com/doi/10.1002/ecm.70053
Image credit: Madison Stevens / Polar Bears International