How sea ice processes and climate fluctuations affect the demography an Arctic diving seabird?

• Main Authors: 3rd World Seabird Conference 2021, Jan, Pierre-Loup
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Underline Science Inc. 2021
• Subjects: Ecology; FOS Biological sciences; Ecosystem; Ornithology; Arctic; Cooper Island; Beaufort Sea; Black guillemot; Cepphus grylle; Sea ice
• Online Access: https://dx.doi.org/10.48448/h9zh-4q57; https://underline.io/lecture/34860-how-sea-ice-processes-and-climate-fluctuations-affect-the-demography-an-arctic-diving-seabirdquestion

Abstract: Mandt's Black Guillemot (Cepphus grylle mandtii) is one of the few Arctic seabirds dependent on sea ice and associated waters throughout the year. This species has undergone a long-term decline since the early 1990s, coinciding with a shift in the Arctic Oscillation causing increased atmospheric temperatures and sea ice melt throughout the Arctic. The largest breeding colony of the species in the Beaufort Sea, at Cooper Island, has been monitored annually since 1975. At its most prolific time, in 1987, the colony supported 209 breeding pairs, while in 2019 only 80 pairs bred. Past studies showed that climatic and oceanographic changes are linked to the observed decline: breeding productivity of this colony has decreased as decreasing summer sea ice reduced prey availability to parents provisioning nestlings. However, a full understanding of the demographic response of the colony to the recent environmental changes in the region requires to study its whole population dynamic. To fulfill this aim, we are analyzing a 45-year database with detailed information on the breeding and survival of 5456 individuals with known histories. Results indicate a high sensitivity of the population growth to immigration and experienced breeder survival. We found a decrease in immigration to be the most important factor in the colony's decline, with a positive correlation between summer sea ice concentration at source colonies and subsequent immigration rate on Cooper Island. We are currently expanding the model to include environmental covariates and quantify their respective influence on the demographic parameters, and preliminary results already suggest that survival of black guillemots is positively correlated with sea ice extent in winter foraging area. Our long-term monitoring data and model provide one of the few biological evidence of the consequences of recent sea ice loss to Arctic bird populations and Artic biota in general. Authors: Pierre-Loup Jan¹, Christophe Barbraud¹, Stéphanie Jenouvrier², George Divoky³ ¹French National Centre for Scientific Research, ²Woods Hole Oceanographic Institution, ³Friends of Cooper Island