Small mammals are a group of species central to northern terrestrial ecosystems because of their predominance in the diet of predators and their significant consumption of crop production. Northern populations are subject to a three to four-year abundance cycles whose fluctuations lead populations to densities close to 0 to more than 10 to 15 individuals per hectare. These abundance cycles vary from one site to another mainly at the level of amplitudes, but recently, the cycles of certain populations of small European mammals have collapsed, coinciding with recent climate changes. In the Canadian Arctic, lemmings continue to fluctuate in three or four-year cycles, but few populations have been monitored over the long term and our understanding of the mechanisms leading to the cycles is still limited. Three sites in the high Arctic (Bylot Island) and low Arctic (Cambridge Bay and Salluit) were selected for their populations of small mammals with different population dynamic properties. Among the species studied, the Ungava lemming, a species endemic to Quebec and Labrador, will be monitored in Salluit to document this species, which is probably the least documented rodent in Quebec. New specimens will be collected at each site for taxonomic purposes. National and international collaborations will compare Canadian population cycles with other sites in Canada, Greenland, Fennoscandia and Russia.

Principal investigator: Dominique Fauteux.