Eurasian brown bear (Ursus arctos arctos) female, Stari Kot, Slovenia. Credit: Charles J. Sharp, Sharp Photography, sharpphotography.co.uk
Key points:
- Researchers analyzed the genomes of ancient brown bears to determine the basis of range reductions and regional restrictions that occurred during the last Ice Age.
- Genetic diversity linked to ancient brown bears is absent in today’s populations, as the ancient bears went extinct rather than moving with the shifting environment.
- These findings help quantify patterns of current diversity and inform predictions about how species may respond to future environmental change.
The brown bear is one of the few large carnivores that survived the end of the last Ice Age. Although these bears are ecologically flexible and have a broad dietary range, they still experienced extensive range reductions and regional extinctions during the last Ice Age. To date, scientists have not identified the underpinnings of the decline or disappearance of bear populations.
Now, in a study published in the Proceedings of the Royal Society B, researchers address the evolutionary relationships between brown bears across space and time. They studied the genomes of ancient brown bears dated to between 3,800 and 60,000 years old, including several individuals from outside their current range.
They determined that brown bear populations went extinct rather than moving with the shifting environment. The analyses revealed that ancient brown bears represent genetic diversity that is absent in current populations. Despite surviving global extinction, brown bears suffered major losses of their historical range and genetic diversity.
These findings shed new light on a critical period in the brown bear history and reveal the type of challenges they faced during and after the last Ice Age. In fact, this type of analysis helps scientists make inferences about how species changed through time and how they may adapt in the future.
“As we continue to grapple with the challenges of coexistence between humans and wildlife, insights from the deep past are invaluable in shaping a sustainable future,” explained senior author Michael Westbury of the University of Copenhagen. “By including samples from the past and from areas a species no longer exists, we can better quantify how patterns of current diversity arose, and inform predictions about how they may respond to future environmental change.”