Item – Thèses Canada

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Numéro d'OCLC
55105217
Lien(s) vers le texte intégral
Exemplaire de BAC
Exemplaire de BAC
Auteur
Reed, Eric Thomas.
Titre
Coûts des soins parentaux et effets des conditions environnementales sur la reproduction de la grande oie des neiges.
Diplôme
Thèse (Ph. D.)--Université Laval, 2003.
Éditeur
Ottawa : National Library of Canada = Bibliothèque nationale du Canada, [2004]
Description
3 microfiches
Notes
Comprend des références bibliographiques
Résumé
This thesis' objective was to quantify investment and costs (reduced future survival or reproduction) associated with prolonged parental care, as well as the effects of environmental conditions on the demography of Greater Snow Geese ('Chen caerulescens atlantica') nesting in the Canadian High Arctic. Data were collected from 1990-2001 at Bylot Island (Nunavut), on staging areas (Québec) and on the wintering grounds (USA). We first quantified individual variation in the duration of parent-offspring association and the costs associated with prolonged parental care. Our results indicate that family break-up between fall and spring was mostly due to mortality of offspring whereas separations of families became important between spring and summer. We present empirical evidence of a survival cost for females providing care for 10 months or more but no cost on future reproduction. We next looked at moult migration. The majority of adult non-breeders and failed nesters left Bylot Island for the moult. The potential negative effect of an auxiliary marker (neck bands) was also examined. Neck-banded females had reduced breeding probabilities and clutch size but their survival was not affected. This negative effect is likely due to increased energetic expenditure during flight. Finally, we studied the effects of environmental conditions on demographic parameters. Our results indicate that juvenile survival, hence recruitment of individuals in the breeding population, was negatively related to an individual's hatching date. Juvenile survival was also highly variable among cohorts but this variation could not be explained by the environmental variables considered. Indirect trophic interactions caused by common predators resulted in almost null recruitment of individuals in lemming crash years. Finally, reproduction probabilities of sexually mature adults were highly variable among years, and this variation could be explained in part by spring snow cover. These results show costs associated with long-term parental care and the importance of environmental conditions on the dynamics of this population.
ISBN
0612802752
9780612802759