When the extreme becomes the norm for Arctic animals

APRIL 8, 2019

by Norwegian University of Science and Technology

Think of reindeer on Norway's Svalbard archipelago as the arctic equivalent of sloths. It's not a perfect analogy, except that like tropical sloths, Svalbard reindeer move as little as possible to conserve energy.

This, combined with the fact that they don't have any predators, allows them to stay in the same area year-round, nibbling on the grasses, herbs and sedges they can find. When snow comes, they simply paw it away and keep nibbling. It's a lifestyle that has allowed Svalbard reindeer to persist over the millennia, long enough for them to adapt physiologically and evolve into a separate subspecies.

But over the last few decades, the warming climate has brought more rain and less snow in some winters. These rain-on-snow (ROS) events can cause ice to form on the ground. The ice coats the reindeer's preferred food and causes them to starve— a potential catastrophe.

In a study just published in Nature Communications, researcher Brage Bremset Hansen, from the Norwegian University of Science and Technology's Centre for Biodiversity Dynamics (CBD) and colleagues describe how they modeled the effects on reindeer population dynamics if icing becomes the norm, rather than an extreme event.

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