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Faire face à l'hiver - Quelles réponses à l'hétérogénéité de la ressource en agroécosystème ? L'exemple de l'alouette des champs (Alauda arvensis)

Abstract : Both quantity and quality of food vary in time and space under the influence of environmental conditions. It is now recognized that a decrease of food is involving in a decline for many species of seed-eating farmland birds. According to this heterogeneity, individuals promote strategies to ensure individual and collective energy needs. In this context, this work has focused on understanding the strategies developed in an avian species characteristic of farmland. The experimental study of the trade-off between foraging and predation reveals the importance of environmental variables related to the resource, the group-size and group density, or the predation risk on the intake rate of individuals. More surprisingly, our results have shown sexual differences in energy acquisition strategies. The choices made by individuals under this trade-off have strong consequences on habitat selection. The study of the aggregative response has highlighted the impact crop type and different landscape variables in habitat use, more specially for foraging habitat. Finally, a study on the sex ratio in relationships with latitude in France has been able to demonstrate a spatial segregation between the sexes, with a high proportion of males in the north. This sexual segregation could be related with different physiological capabilities (energy expenditure and hypothermia), emphasizing a greater tolerance of males at low winter temperatures encountered in the higher latitudes during wintering period.
keyword : Alauda arvensis
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https://tel.archives-ouvertes.fr/tel-00748810
Contributor : Martine Lacalle <>
Submitted on : Tuesday, November 6, 2012 - 9:52:42 AM
Last modification on : Thursday, January 11, 2018 - 6:14:38 AM
Long-term archiving on: : Thursday, February 7, 2013 - 3:44:07 AM

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  • HAL Id : tel-00748810, version 1

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Thibaut Powolny. Faire face à l'hiver - Quelles réponses à l'hétérogénéité de la ressource en agroécosystème ? L'exemple de l'alouette des champs (Alauda arvensis). Sciences de l'environnement. Université de Poitiers, 2012. Français. ⟨tel-00748810⟩

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