Marie-Andrée Giroux

Université du Québec à Rimouski
Postdoctoral fellow candidate

Supervisor: Dominique Gravel
Nicolas Lecomte
Start: 2014-09-01
End: 2015-08-31
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EMPOWER North : Establishment of a Multidisciplinary research PrOgram to Widen our undERstanding of NORTHern ecosystems
One key question in ecology is whether plant-herbivore or predator-prey interactions drive the functioning of ecosystems. According to the exploitation ecosystems hypothesis, tundra plants are productive enough to support herbivore populations in the Arctic, but the abundance of arctic herbivores is too low to support viable arctic predator populations. Hence, plant-herbivore interactions should drive the functioning of arctic food webs. This hypothesis, however, has failed to predict the relatively diverse structure of many arctic food webs, likely because it does not take into account that food resources originating from other ecosystems (e.g. seals, migratory birds) can subsidize arctic predators. My postdoctoral project will combine theoretical, empirical, and educative approaches to determine whether a model including the consumption of food subsidies by predators better predict the relative strength of predator-prey and plant-herbivore interactions in northern food webs. Specific objectives: 1. Investigate the impacts of food subsidies on the strength of predator-prey interactions along a gradient of primary productivity in northern food webs, combining theoretical modeling and empirical analysis of an existing dataset. This dataset has been collected through a circumpolar and circumboreal network of northern field sites. 2. Contribute to a circumpolar and circumboreal research effort by pursuing the ecosystem monitoring project on Igloolik Island, Nunavut. 3. Include northerners in a circumpolar and circumboreal research effort to monitor northern terrestrial ecosystems by establishing a training program for future community leaders in arctic research.