Arctic Sci. (2018)

Cycles of population boom and bust are common in Arctic species. Lemmings are perhaps the best known example, and their population cycles are ecologically important in the high Arctic. Surprisingly, the drivers of these cycles remain a matter of debate. As lemmings live for much of the year under the snow, modulating the winter climate that they experience (the subnivium), changes in snow cover could contribute to these dynamics.

figure a

Wildscotphotos/Alamy Stock Photo

Florent Domine from the Université Laval, Canada, and CNRS, France, and co-authors investigate the influence of physical snowpack characteristics on brown lemming population dynamics in the Canadian high Arctic using lemming population data and snow modelling over the period 2003–2014. They were particularly interested in the effects of the hardness of the basal layer of snow — which is determined by rain-on-snow events and wind storms in autumn.

They find that winter lemming population growth shows a strong negative response to rain-on-snow occurrence and that summer population and winter nest densities are also negatively affected, although to a lesser extent. The increasing occurrence of rain-on-snow events projected under climate warming can be expected to strongly impact lemming populations and consequently the wider high Arctic ecosystem.