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Small mammals have an essential role in the food web of many ecosystems of the world, the arctic not being an exception. Having a great influence on their predators and other prey, lemmings are key players in the food web of the terrestrial artic ecosystem and the study of their populations is very important. Nevertheless, we know very little about the factors affecting the spatial distribution of lemmings and the relation to their habitat. Lemmings require protection from predators, protection from the winter cold through an adequate snow cover and access to high quality food. Their basic needs are threatened by climate change, notably by an increase of global temperature, which negatively affects plant growth and snow quality.
Thus, the project objective is to characterize the habitat use of brown lemmings (Lemmus trimucronatus) and collared lemmings (Dicrostonyx groenlandicus) at different spatial levels, in the High Arctic. At the smallest scale, the objective is to establish what are the influences of biotic (e.g. plants) and abiotic elements (e.g. topography, snow) on microhabitats use. On a larger scale, the goal is to understand how the distribution of the two species varies among habitats.
The CEN research station on Bylot Island has been visited by a large number of researchers in the last decades because of its exceptional abundance of wildlife. Habitat utilization at a small scale will be compared between years of high and low lemming abundance and between the different habitats (mesic and humid). In order to characterize which biotic or abiotic elements influence habitat use, some measures will be taken such as the plant cover by dominant species, the softness of the soil to dig burrows, the microtopography and the snow conditions (height during winter and persistence during spring). Those elements will be measured during 2019 and 2020 summers and related to the number of lemmings captured at each station of our trapping grids. To look at habitat use at a larger scale, four sites spaced out by up to 45 km on Bylot Island will be compared. The type of soil, the dominant habitat (mesic or humid), the dominant floral composition and the snow cover will be the habitat elements measured.
This project will lead to a better understanding of how lemmings use their habitat and how they access the resources they need to survive. This new knowledge will help to better apprehend how climate change will affect those small mammals at different spatial scales. Indeed, it will be easier to take decisions about how we conserve and manage the fragile and unique arctic ecosystem and its native fauna.