In search of Ivory Gull: a sentinel species of climate change in the most threatened and remote areas of Greenland – Phase III

Species living in the Arctic are facing strong environmental changes. Forecasting impacts of such changes on endemic Arctic species require a full understanding of their ecology and habitat requirement. A limited number of sea ice-associated Arctic species act as sentinel species, whose ecological responses to the consequences of environmental modifications deserve special attention and can set an example for all Arctic biota. This is the case of the ivory gull (Pagophila eburnea), a species that entirely completes its life cycle in the Arctic and is thus directly facing impacts of the arctic alteration. This proposal follows two previous phases (Ivory-1 and Ivory-2) of our long-term research program focusing on ivory gull populations in Northern Greenland under climate change and other environmental modifications. In this new phase, our objective is to expand our investigations of the demographic trend, social structure, and contaminant load of this arctic species. In the first two phases of our project, (i) we combined genetic and genomic information to infer recent demographic trajectory and genomic structure of populations, (ii) we used GPS tracking to infer movements and habitat selection by ivory gulls, and iii) we documented mercury contamination and potential health risks to ivory gulls in comparative and meta-analyses studies. We also preliminarily investigated these contaminant loads in relation with the trophic position of the species in its last Greenlandic breeding strongholds. On the basis of the results obtained, in this third phase we intend to continue this work by improving and extending the information collected in order to answer some of our open questions (in particular on demography, adult survival and the relationship between trophic position and contaminant load) and to develop new ones, in particular on social structure, breeding behavior, dispersal and the causes and consequences of the unexpected sex ratio observed in the species (approximately 70% males). Overall the complementary approach we developed in this long-tern program should produce fundamental biological information for the conservation of the ivory gull, making the species a sentinel of environmental change in the most threatened and remote areas of Greenland.