Climate impacts on Mediterranean blue tit survival: an investigation across seasons and spatial scales

Authors

  • VLADIMIR GROSBOIS,

    1. Centre d'Ecologie Fonctionnelle et Evolutive, CNRS, 1919 Route de Mende, 34293, Montpellier cedex 5, France,
    2. Department of Biology, Campus Drie Eiken, University of Antwerp, B-2610 Antwerp, Belgium,
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  • PIERRE-YVES HENRY,

    1. Centre d'Ecologie Fonctionnelle et Evolutive, CNRS, 1919 Route de Mende, 34293, Montpellier cedex 5, France,
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    • 1Present address: UMR 5173, Departement d'Ecologie et Gestion de la Biodiversité, Muséum National d'Histoire Naturelle, 55 rue Buffon, 75005 Paris, France.

  • JACQUES BLONDEL,

    1. Centre d'Ecologie Fonctionnelle et Evolutive, CNRS, 1919 Route de Mende, 34293, Montpellier cedex 5, France,
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  • PHILIPPE PERRET,

    1. Centre d'Ecologie Fonctionnelle et Evolutive, CNRS, 1919 Route de Mende, 34293, Montpellier cedex 5, France,
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  • JEAN-DOMINIQUE LEBRETON,

    1. Centre d'Ecologie Fonctionnelle et Evolutive, CNRS, 1919 Route de Mende, 34293, Montpellier cedex 5, France,
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  • DONALD W. THOMAS,

    1. Centre d'Ecologie Fonctionnelle et Evolutive, CNRS, 1919 Route de Mende, 34293, Montpellier cedex 5, France,
    2. Groupe de Recherche en Ecologie, Nutrition et Energétique, Centre de Recherche en Biologie Forestière, Université de Sherbrooke, Sherbrooke, Québec JIK 2R1, Canada
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  • MARCEL M. LAMBRECHTS

    1. Centre d'Ecologie Fonctionnelle et Evolutive, CNRS, 1919 Route de Mende, 34293, Montpellier cedex 5, France,
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Vladimir Grosbois, Centre d'Ecologie Fonctionnelle et Evolutive, CNRS, 1919 Route de Mende, 34293, Montpellier Cedex 5, France, e-mail: vladimirgrosbois@hotmail.com

Abstract

In some hole nesting passerine species, long-term monitoring data are available for several geographically independent populations. Climate forcing can then be documented and predictions made on the scale of distribution ranges. Several demographic studies of Paridae report dramatic impacts of wintertime climatic factors. However, these studies were undertaken in populations located in the northern parts of the species' ranges. Studies on the survival of Paridae in their southern ranges are necessary in order to assess potential latitudinal variation in climate forcing on survival. Based on monitoring of individual adult blue tits (Parus caeruleus), the effects of climatic factors on annual survival were assessed in three distinct Mediterranean populations. In these regions, climatic conditions in early summer might be expected to have a strong impact because they can be extremely hot and dry and because at this time of year Paridae are subjected to intrinsic constraints that stem from energetically costly postbreeding moult, recovery from reproductive costs, and from population densities inflated by the new cohort of fledglings. The impact of climatic conditions in early summer was, thus, addressed in addition to that prevailing in winter. In order to consider a large number of local climatic variables while limiting statistical power loss, integrative indices of local climate were built using multivariate techniques. In addition, the NAO and three large-scale factors that are closely linked with atmospheric and oceanic circulation in the intertropical zone were considered as potentially influential factors in winter and early summer. Relationships between blue tit survival and indices of local temperature and precipitation in winter and in early summer were detected. Adult survival also correlated with a large-scale tropical index in early summer: rainfall in the Sahel. This is one of the first quantitative indications that fluctuations in summer climatic conditions explain a significant part of the temporal variation in adult survival in unconnected populations of a sedentary European vertebrate. Furthermore, the results support the hypothesis that summertime local climates in Western Europe are closely linked with atmospheric and oceanic circulation in the intertropical zone.

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