Direct and indirect impacts of different parasite-predator-prey interactions on the cyclic dynamics of an Arctic terrestrial vertebrate community subject to climate change

The Arctic region is warming more rapidly than any other region on Earth, and predict the response of biodiversity to climate change (CC) has become an extremely active field of research. Most studies of the impacts of CC on biodiversity have so far focused on individual responses, mainly on phenology, physiology or range shifts. However, it is increasingly apparent that biotic interactions drive key ecological and evolutionary processes and mediate ecosystem responses to CC. Thus, predicting the effects of CC is dependent upon identifying the interactions between species that are most vulnerable to changing climate and are key determinants of the structure and function of a community.

Predator-prey interactions (PPI) play a determinant role in structuring Arctic terrestrial vertebrate communities, and understanding how the strength of these interactions varies under the constraints of CC is crucial to assess ongoing changes in Arctic biodiversity.

If PPI is primarily seen as the direct trophic (lethal) interactions between prey and predator species, at a community level it can also take many different forms. Thus, PPI can be non-trophic/non-lethal when predators induce antipredator responses (risk effects) in preys, hence not necessarily impacting their current abundance but rather their long-term survival and/or their breeding performances.

This project is the continuation of our “INTERACTIONS-1036” program funded by the French Polar Institute-IPEV between 2011 and 2014 and extended during 2015-2018. In our previous programs, we have deepened our understandings of the direct and indirect interactions between lemmings, shorebirds and their shared predators.
The new INTERACTIONS program (2019-2022) will now aim at capitalizing on this expertise in order to broaden the picture to far more complex inter-specific interactions, and involving two aims:
– observations at larger time scale on the previously studied site in order to better appreciate the effect of yearly fluctuation;
– extension to the study of individual responses of predators and prey to the intensity of their interactions.

The originality of our new program consists in the mutual study of the behavioural responses of the prey and the predators to the variations of intensity of their interactions, and the consequences for the dynamics and distribution of the different populations.

Better understanding of the evolution of the predator-prey interactions in Arctic terrestrial ecosystems could have strong implications in our ability to understand the effects of CC on biodiversity and evolution.