Climate change

How will Arctic mammals react to climate change?

With the iconic polar bear on thin ice as global warming melts its hunting ground, how will other Arctic mammals fare? Computer modeling allows us to predict how species have responded to climate change in the past and what the outcome will be for them in the future.

Now, a new set of models has been developed to predict the responses of cold-adapted species, particularly in the face of current global warming. Previously, the “expansion-contraction” model was the only model used in Europe to study the responses of species to glacial-interglacial cycles. However, this model is more suitable for tropical and temperate species, and less applicable to arctic species.

“Arctic species are suffering the most from global warming and without a doubt, humans are responsible for this trend,” says author Dr Joanna Stojak of the Polish Academy of Sciences (Poland). “We can’t go back, but hopefully we can still prevent the next mass extinction. And the best start is understanding how global warming is influencing Arctic taxa. »

To carry out this new model, the biogeographical history of terrestrial mammal species adapted to the cold was described, making it possible to identify the responses to glacial cycles and climatic fluctuations. From this research, three new response patterns were identified:

  • Extinction and genetic decrease
  • Termination and replacement
  • Contraction and gene transfer

In the “genetic extinction and decline” response, previously widespread populations have locally disappeared, biogeographic areas have contracted, and the remaining populations have been characterized by low genetic diversity. This is the case of the narrow-headed vole (Lasiopodomys gregalis), Collared Lemming (Dicrostonyx spp.) and the Norway lemming (lemma lemma).

For species like the arctic fox (Vulpes lagopus), wolverine (Gulo Gulo) and reindeer (Rangifer tarandus), their response corresponded to an “extinction and replacement” pattern, where some local populations disappeared, but were replaced by migrating lineages seeking refuge elsewhere. In contrast, the mountain hare (shy lepus) and sable (Martes zibellina) were best modeled by “gene contraction and transfer”, where the biogeographic ranges of these species contracted, while temperate species expanded, resulting in gene transfer between arctic and more temperate species.

“We took a closer look at past and present changes in the genetic diversity of different cold-adapted species and how their ranges were shifting with climate change,” Stojak says. “It was very exciting to see that different taxa reacted differently, but we were still able to identify clear and common patterns.”

These models come at a crucial time to understand the different ways in which cold-adapted species may respond to human-induced climate change and will help inform better decision-making for biodiversity and habitat conservation of the most critical species. more threatened.

This work was published in Mammal review.

An antique illustration of arctic animals, including mammals modeled in this study – wolverine, arctic fox, lemming, reindeer and sable. Credit: mikroman6 / Getty Images

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