Dynamics of a prey-predator system of marine birds in Antarctica

• Main Author: Viollat, Lise
• Other Authors: INSTITUT AGRO Agrocampus Ouest, Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro), Centre d'études biologiques de Chizé (CEBC), 405 route de Prissé la Charrière, 79360 Villiers-en-Bois, Frédéric Hamelin, Christophe Barbraud, Maud Quéroué, Olivier Gimenez
• Format: Master Thesis
• Language: French
• Published: HAL CCSD 2021
• Subjects: State-space model; Integrated population model (IPM); Seabirds; Prey-predator systems; Demography; Bayesian inference; Modèle à espaces d'états; Modèle de population intégré (IPM); Oiseaux marins; Systèmes proies-prédateur; Démographie; Inférence bayésienne; [SDV]Life Sciences [q-bio]; McCormick; Pointe-Géologie; Manchot; Empereur; Antarc*; Antarctica; Antarctique*; Aptenodytes forsteri; Pygoscelis adeliae; Stercorarius maccormicki
• Online Access: https://dumas.ccsd.cnrs.fr/dumas-03572822; https://dumas.ccsd.cnrs.fr/dumas-03572822/document; https://dumas.ccsd.cnrs.fr/dumas-03572822/file/2021_Viollat_Lise_MODE.pdf

One of the greatest challenges of population ecology is to assess the complex mechanisms of climate and interspecific relationships on population dynamics. The aim of our study is to understand the effect of inter, intraspecific interactions and environmental conditions on the demographic parameters of a prey-predator system of three seabirds' populations nesting at Pointe-Géologie archipelago, Antarctica, which play major roles in the polar ecosystem: the south polar skua (Stercorarius maccormicki), and its two main preys during the breeding season, the Adélie penguin (Pygoscelis adeliae) and the emperor penguin (Aptenodytes forsteri). We built two monospecific models: an integrated population model (IPM) from count and capture-recapture data for the skuas and a state-space model from count data for Adélie penguins, to estimate their demographic parameters and their abundances. We then used Bayesian linear models to evaluate the effects of climatic covariates and of the abundance of predators and their prey on the posterior distribution of the parameters estimated by the two models. Our results show that the demography of skuas and Adélie penguins is sensitive to intraspecific density-dependence, interspecific interactions, and environmental conditions. This system is, therefore, drive-by top-down processes and by density dependence. We also highlighted differences in responses to the intrinsic and extrinsic factors of skuas according to their reproductive status of the previous year. L’objectif de notre étude est d'évaluer les effets des interactions inter et intraspécifiques et des conditions environnementales sur les paramètres démographiques d'un système proies-prédateur de trois populations d'oiseaux marins nichant en Antarctique : le labbe de McCormick (Stercorarius maccormicki), et de ses deux proies principales pendant la saison de reproduction, le manchot Adélie (Pygoscelis adeliae) et le manchot empereur (Aptenodytes forsteri). Ces oiseaux marins jouent des rôles majeurs dans le fonctionnement de ...