David Bolduc

Université Laval
M.Sc. candidate

Supervisor: Pierre Legagneux
Dominique Fauteux, Musée Canadien de la Nature
Start: 2020-09-01


Role of the ermine in lemming cycles in the Canadian High-Arctic
Small mammals play an essential role in their respectives ecosystems. This is especially true when their abundance varies widly, temporarly creating ideal conditions for the reproduction of their predators and modifying the interactions between species. The exact causes of their periodic fluctuations are still unknown,but small mustelids are thought to set the rythm of these cycles. This project thus aims to caracterise the ermine (Mustela erminea) population dynamics on Bylot Island, in the Canadian High-Arctic, where brown (Lemmus trimicronatus) and collared lemmings (Dicrostonyx groenlandicus) present 3-4 years abundance cycles. Our first objective is to evaluate if ermines have a cyclic dynamic like their prey. We will use time series of incidental observations, winter relative abundance and long-term presence-absence data. Our second objective is to test the specialist predator hypothesis, which stipulates that small mustelids are causing small mammals cycles. We will first evaluate the dependency between ermine abundance and lemming densities, and then estimate the effect of ermine predation on lemming winter growth rate and spring densities. This project will shed light on the role of this cryptic predator on lemming populations, and thus on the whole Arctic ecosystem.