Mouvement, Abondance, Distribution
Marius SOMVEILLE
- Publication : 16 février 2012
Ancien membre de l'équipe DPB - cette page n'est plus maintenue
(date de dernière mise à jour: 05/11/2015)
Doctorant
Evolutionary Ecology Group
Department of Zoology
University of Cambridge
Downing Street, Cambridge, CB2 3EJ
United Kingdom
et
CEFE/CNRS
Campus du CNRS
1919, route de Mende
34293 Montpellier cedex 5
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Directeurs de Thèse : Andrea Manica (University of Cambridge) et Ana Rodrigues (CEFE)
Etablissement d’inscription : University of Cambridge, UK
Projet : The global ecology of bird migration: patterns and processes.
Thesis Summary:
Nearly twenty percent of bird species are migratory, their seasonal movements causing a redistribution of bird diversity that radically changes avian community composition worldwide. And yet, bird migration has been largely ignored in studies of global avian biodiversity. This thesis is the first macroecological study of the global bird migration system, using the global patterns of migratory bird diversity to test hypotheses for the ecological processes driving bird distributions in space and time.
Using a dataset on the geographical distributions of the world’s birds, in chapter two I start by mapping global diversity patterns associated with bird migration. Despite their great biological and ecological diversity, strong spatial patterns emerge when all migratory species are pooled together. In chapters three to five I test hypotheses for the ecological patterns underpinning these processes. In chapter three, results of correlative statistical models strongly indicate that migratory birds move to their breeding grounds to exploit a seasonal surplus in energy and resources, and then redistribute to the nearest suitable non-breeding grounds. In chapter four, I find that, underneath their great diversity of breeding and nonbreeding destinations, migratory birds appear to follow a common strategy of tracking their climatic niche year-round, within a broader trade-off between the costs of migration and the benefits of better access to resources. From the results of these statistical correlative analyses, I develop in chapter five a global spatially-explicit, process-based, mechanistic model of the global bird migration system. Building from first principles (to account for the energy use by species across the year and including key ecological and biological processes), this model successfully explains the diversity patterns of migratory bird diversity quantified in chapter two.
Overall, this thesis work advances understanding of the mechanisms driving bird migration worldwide, shedding light into one of Nature’s most fascinating phenomenon.