Polar bears are the icons of the Arctic region but also remain one of the most threatened species as the climate crisis intensifies. Currently, they are on track to be extinct by 2100 if the amount of greenhouse gas emissions remains unchanged, a 2020 study published in the journal Nature Climate Change said.
While detailed monitoring of these elusive animals is important for conservation, it can put them under stress. To address this, scientists have developed a new tool that uses their DNA from snow tracks.
The new study, published earlier this week in the journal Frontiers in Conservation Science, took inspiration from forensic techniques which can be applied to tiny, degraded DNA samples. Using these techniques, there is no need to physically capture bears, which can be dangerous for both the animal and humans and can be concerning for some local indigenous communities. Instead, the scientists looked at DNA present in their snow tracks to identify them, a press release explains.
“It is particularly challenging, expensive, and time-consuming to find polar bears in the Arctic, let alone count them and understand how they are coping with climate change,” senior author Melanie Lancaster said in the statement.
A common form of environmental DNA can be found when animals defecate. However, the DNA quality is not always sufficient for the analysis needed for conservation, the statement adds. However, snow tracks have fresh cells and the DNA is intact because of the cold temperature, which acts as storage.
For this study, the scientists collected snow from individual tracks made by Alaskan polar bears and Swedish Eurasian lynxes in the wild and captivity. The findings revealed that nuclear DNA from 87.5% of wild polar bear tracks and 59.1% of wild lynx tracks could be retrieved. Furthermore, 13 of the wild polar bear samples could be genotyped, identifying 12 different individuals, the statement adds.
The scientists hope that this non-invasive technique can significantly help in the conservation of these animals, better understand their populations and behaviour, and manage conflict with humans. “We hope this method will be taken up by the polar bear research community, with the involvement of hunters, volunteers, and Indigenous communities, as a new way to collect information on polar bears,” Lancaster said in the statement.