INTERACTIONS (long-term project): A joint circumpolar project to measure and predict the cascading impacts of “Indirect Trophic in arctic terrestrial vertebrate communities. Period 2023-2026 (related to our ANR funded project): PArental Care Strategies (PACS) of arctic shorebirds: consequences of the interplay between abiotic conditions and predator-prey interactions on breeding success

There is ample evidence that climate changes (CC) are among the most influential drivers of biodiversity, and predicting the consequences of CC on species and their ecosystems is a major challenge for ecologists. Most studies have concentrated on the effects of CC of phenology and physiology on organisms, as well as changes in the distribution and range shifts of species. By contrast, detailed studies of animal behaviour and species interactions remain scarce. Thus, in the current context of CC, understanding the relative contributions of abiotic and biotic factors in driving the behaviour of species remains among the major questions for ecologists. Abiotic factors (here including temperature, precipitations, snow regimes and, by extension, primary productivity) directly impact breeding success of birds, and are expected to induce modulation of their parental care strategies (PACS). However, PACS can also be influenced by biotic interactions like predation. Furthermore, individual responses (incl. PACS) to changes in abiotic factors and predator-prey interactions are often studied separately, while they may act in synergy. Thus, understanding the complex interplay between abiotic factors and biotic interactions is essential to fully understand how individuals cope with their changing environment and to what extent they can respond to ongoing CC.

In the Arctic, two main PACS co-occur in closely related Arctic shorebirds: biparental care, in which both parents share incubation duties, and uniparental care, in which only one adult incubates the eggs. In addition to harsh and changing abiotic conditions, these ground nesting birds must mitigate strong predation risk by arctic fox, the main cause of breeding failure. Because the Arctic region is warming more rapidly than any other on Earth, this region and its species are highly exposed to CC and particularly suited to answer our questions.

This project is the continuation of our “INTERACTIONS-1036” project funded by the French Polar Institute-IPEV between 2011 and 2022. For the duration of this project we want to place shorebirds at the centre of our project in interaction with a generalist predator (Arctic fox) and its main prey species (lemming) by focusing on the study on their incubation strategies in the current context of changes in abiotic conditions and predation risk. Building on results from the previous « Interactions » project and thanks to our long-lasting collaborations with other international research teams, our research objectives are twofold:

– How shorebirds mitigate the trade-off between incubation and foraging as an adaptive response to local climate conditions and food availability.

– How the spatial and temporal variations of predation risk by predators, mainly arctic foxes, impact the incubation strategies, breeding success and distribution of shorebirds.
In the coming years we wish integrate ours results in a synergetic model to assess the relative importance of abiotic factors and inter-specific interactions in explaining observed predation rates on shorebird nests.