Polar seabirds, sentinels of the sea ice : Demographic responses and life history traits

• Main Author: Sauser, Christophe
• Other Authors: Centre d'Études Biologiques de Chizé - UMR 7372 (CEBC), Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Université de La Rochelle, Christophe Barbraud
• Format: Doctoral or Postdoctoral Thesis
• Language: French
• Published: HAL CCSD 2020
• Subjects: Demography; Seabirds; Sea ice; Antarctica; Sentinels species; Démographie; Oiseaux marins; Glace de mer; Antarctique; Espèce sentinelle; [SDV.BA]Life Sciences [q-bio]/Animal biology; Nivea; Sentinelles; Southern Ocean; Antarc*; Antarctique*; Cape Petrel; Daption capense; Snow Petrel; Snow Petrels
• Online Access: https://tel.archives-ouvertes.fr/tel-03342325; https://tel.archives-ouvertes.fr/tel-03342325/document; https://tel.archives-ouvertes.fr/tel-03342325/file/2020SAUSER154889.pdf

The impact of climate change on sea ice and polar ecosystems has been well recognized. However, these environments are generally difficult to study because of their extreme climate, isolation and the associated logistical difficulties. The lack of knowledge regarding the mechanisms linking the life history traits of polar organisms and sea ice variation limit our understanding of the consequences of climate change on long-lived species such as polar seabirds and sea ice ecosystems. Seabirds, generally located at the top of food webs, could however constitute sentinel species of ecosystems linked to sea ice. The objective of this thesis is to improve knowledge on the processes involved in the responses of polar marine predators to environmental variations, and mainly the mechanisms linked to sea ice. For this purpose we have based our analyses on the long-term monitoring of two polar seabirds, the snow petrel (Pagodroma nivea) and the Cape petrel (Daption capense). Both species breed in polar environments of the Southern Ocean. One is particularly dependent on sea ice for foraging (snow petrel) while the other prefers ice-free habitats (Cape petrel). During this PhD, we estimated the influence of extrinsic factors (top-down, bottom-up, local weather) and intrinsic factors (age, breeding experience, sex and colony) on the demographic responses of these two species using multi-states capture-recapture models. We also tested the influence of environmental factors on phenotypic traits (body condition and breeding phenology) of snow petrels. For the Cape petrel, we show a decrease in breeding success as well as an influence of several extrinsic parameters (sea surface temperature, predation, local weather) on this demographic parameter. We also show an increase in adult survival linked to variations of a large scale climate index, the southern annular mode. Modelling of the population dynamics using a matrix population model indicated a positive population growth rate and suggest that this species probably ...