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Arctic regions are particularly affected by the global warming and it is possible to anticipate changes in physical properties of snow and a reduction of the snow period. Lemmings reside all year long in the northern regions. They have to spend up to 9 months under the snow but they do not stop their activities; they dig tunnels to find food and they build nests in which they can reproduce. Many evidence suggests that winter reproduction plays a key role in their population dynamics. Hence, we are looking into how the changes in physical properties of snow affected by global warming could influence the population dynamics of lemmings in the Canadian Arctic. We are particularly interested in the density and the hardness of the basal snow layer, where lemmings live during winter.
Since 2013, probes have been deployed in the Qarlikturvik Valley, on Bylot Island, to measure physical properties of snow (depth, temperature, thermal conductivity) year round. In spring, fieldwork will be done to manually sample physical properties of snow directly in sites used by lemmings (snow drift) and in control sites. In summer, demographic parameters of lemmings will be collected through fieldwork. Abundance, intensity of reproduction and summer survival will be sampled on 3 trapping grids using the capture-mark-recapture method. Wintering nests will also be sampled through line transects to measure wintering abundance and intensity of reproduction by the presence of droppings from young.
This project will help us better understand the effects of climate changes on lemming populations living in Arctic. Being the main prey of resident mammals of the tundra and of many migrating avian predators during the summer, the lemming is an important component in this ecosystem. It is therefore important to have a global view of all the factors that can affect their population dynamics.