Trophic interactions in a connected Arctic: an empirical and theoretical approach

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We live in a connected world. Alike the anthropogenic world, ecosystems are also connected to each other at local to global scales due to movements of nutrients, prey and consumers across ecosystem boundaries. These connections are currently being disrupted by anthropogenic activities at an unprecedented rate. For instance, some migratory populations connecting ecosystems have sharply declined due to various anthropogenic pressures (e.g. salmons, whales), while others have increased exponentially as a result of agriculture intensification (e.g. geese). Ecologists thus face the challenge of understanding how wildlife is affected by a new global pressure, namely human-induced modifications in connections between ecosystems. Although some of these modifications are known to have induced major ecological and economic impacts, the mechanisms underlying their direct and cascading effects on wildlife are still largely unexplored. My research program will aim at better understanding these critical questions. With my students and colleagues, we will determine whether inputs of resources from other ecosystems can 1) impact trophic interactions at global and circumpolar scales, 2) sustain predator populations at a local scale, and 3) impact species of conservation concern at local and circumpolar scales. To do so, I will lead innovative research projects devoted at studying the community of species inhabiting tundra ecosystems. We will mainly look at the consequences of the availability of marine resources and of migratory birds for arctic predators on consumer demography and predator-prey interactions. We will also use key processes occurring in this study system to develop theoretical models to predict the impact of connections between ecosystems on species interactions. These models will be of interest for a broad range of study systems, because inputs of resources from other ecosystems and their consequences are ubiquitous. The insights gained through my research program will have practical implications to solve issues shared by both scientists and society. Some of the proposed projects will investigate whether the recent explosion of tundra-nesting geese, that sustain arctic predator populations, could contribute to explaining the somewhat general decline of shorebird populations at a circumpolar scale. Tackling this conservation issue may require increasing harvesting pressures on geese by residents of the Arctic, and such measures could simultaneously address the food security issues currently experienced by northerners. My research program will thus continue feeding policy makers, both in Canada and abroad, with the knowledge required to implement evidence-based policies in a world under global pressures.