Article

The bioclimatic envelope of the wolverine (Gulo gulo): do climatic constraints limit its geographic distribution?

Canadian Journal of Zoology (Impact Factor: 1.35). 02/2010; 88(3):233-246.

ABSTRACT We propose a fundamental geographic distribution for the wolverine (Gulo gulo (L., 1758)) based on the hypothesis that the occurrence of wolverines is constrained by their obligate association with persistent spring snow cover for successful reproductive denning and by an upper limit of thermoneutrality. To investigate this hypothesis, we developed a composite of MODIS classified satellite images representing persistent snow cover from 24 April to 15 May, which encompasses the end of the wolverine's reproductive denning period. To investigate the wolverine's spatial relationship with average maximum August temperatures, we used interpolated temperature maps. We then compared and correlated these climatic factors with spatially referenced data on wolverine den sites and telemetry locations from North America and Fennoscandia, and our contemporary understanding of the wolverine's circumboreal range. All 562 reproductive dens from Fennoscandia and North America occurred at sites with persistent spring snow cover. Ninety-five percent of summer and 86% of winter telemetry locations were concordant with spring snow coverage. Average maximum August temperature was a less effective predictor of wolverine presence, although wolverines preferred summer temperatures lower than those available. Reductions in spring snow cover associated with climatic warming will likely reduce the extent of wolverine habitat, with an associated loss of connectivity.Nous présentons une répartition géographique fondamentale du glouton (Gulo gulo (L., 1758)) basée sur l'hypothèse selon laquelle la présence des gloutons est restreinte par leur association obligatoire à une couverture persistante de neige au printemps nécessaire pour le succès des terriers de reproduction, ainsi que par la limite supérieure de la thermoneutralité. Afin d'examiner cette hypothèse, nous mettons au point un assemblage d'images satellites classifiées MODIS représentant la couverture persistante de neige du 24 avril au 15 mai, ce qui englobe la fin de la période d'utilisation des terriers de reproduction chez les gloutons. Afin d'examiner la relation spatiale du glouton avec les températures maximales moyennes d'août, nous utilisons des cartes de températures interpolées. Ensuite, nous comparons et corrélons ces facteurs climatiques avec des données géographiques spatiales sur les emplacements des terriers de gloutons et les sites de télémétrie en Amérique du Nord et en Fennoscandie, ainsi qu'avec notre compréhension actuelle de l'aire de répartition circumboréale du glouton. Tous les 562 terriers de reproduction de Fennoscandie et d'Amérique du Nord se retrouvent dans des sites à couverture de neige persistante au printemps. Quatre-vingt-quinze pourcent des sites de télémétrie en été et 86 % des sites en hiver concordent avec la couverture de neige du printemps. La température maximale moyenne en août est une variable prédictive moins efficace de la présence des gloutons, bien que les gloutons préfèrent des températures d'été plus fraîches que celles qui sont disponibles. La réduction de la couverture de neige au printemps associée au réchauffement climatique va vraisemblablement réduire l'étendue de l'habitat du glouton, ce qui entraînera une perte de connectivité.

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