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

Canadian Journal of Zoology (Impact Factor: 1.3). 02/2010; 88(3):233-246.


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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    • "The raster habitat layer for wolverine describes areas with and without persistent spring snow (Copeland et al. 2010). To reduce computation time, we have reduced the study landscape to the Bitterroot Mountain Range along the Montana/Idaho border. "
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    ABSTRACT: 1.Power analysis is an important step in designing effective monitoring programs to detect trends in plant or animal populations. Although project goals often focus on detecting changes in population abundance, logistical constraints may require data collection on population indices, such as detection/non-detection data for occupancy estimation.2.We describe the open-source R package, rSPACE, for implementing a spatially-based power analysis for designing monitoring programs. This method incorporates information on species biology and habitat to parameterize a spatially-explicit population simulation. A sampling design can then be implemented to create replicate encounter histories which are subsampled and analyzed to estimate the power of the monitoring program to detect changes in population abundance over time, using occupancy as a surrogate.3.The proposed method and software are demonstrated with an analysis of wolverine monitoring in the U.S. Northern Rocky Mountain landscape.4.The package will be of use to ecologists interested in evaluating objectives and performance of monitoring programs.This article is protected by copyright. All rights reserved.
    Methods in Ecology and Evolution 03/2015; 6(5). DOI:10.1111/2041-210X.12369 · 6.55 Impact Factor
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    • "In this study we use the wolverine (Gulo gulo) as an example species. Because the wolverine is an obligate carnivore with a northern circumpolar distribution [25] it’s range limits are strongly correlated with snow covered areas [26], [27]. Current research indicates that spring snowpack is a critical resource for providing suitable denning sites to support successful wolverine reproduction [28]. "
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    ABSTRACT: We present a unique water-balance approach for modeling snowpack under historic, current and future climates throughout the Sierra Nevada Ecoregion. Our methodology uses a finer scale (270 m) than previous regional studies and incorporates cold-air pooling, an atmospheric process that sustains cooler temperatures in topographic depressions thereby mitigating snowmelt. Our results are intended to support management and conservation of snow-dependent species, which requires characterization of suitable habitat under current and future climates. We use the wolverine (Gulo gulo) as an example species and investigate potential habitat based on the depth and extent of spring snowpack within four National Park units with proposed wolverine reintroduction programs. Our estimates of change in spring snowpack conditions under current and future climates are consistent with recent studies that generally predict declining snowpack. However, model development at a finer scale and incorporation of cold-air pooling increased the persistence of April 1st snowpack. More specifically, incorporation of cold-air pooling into future climate projections increased April 1st snowpack by 6.5% when spatially averaged over the study region and the trajectory of declining April 1st snowpack reverses at mid-elevations where snow pack losses are mitigated by topographic shading and cold-air pooling. Under future climates with sustained or increased precipitation, our results indicate a high likelihood for the persistence of late spring snowpack at elevations above approximately 2,800 m and identify potential climate refugia sites for snow-dependent species at mid-elevations, where significant topographic shading and cold-air pooling potential exist.
    PLoS ONE 09/2014; 9(9):9. DOI:10.1371/journal.pone.0106984 · 3.23 Impact Factor
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    • "Genetic structure, however, tends to increase towards range peripheries in North America [46], [47], [49]–[51], suggesting irregular distributions of populations [36] due to range contractions [44]. Additionally, spring snow cover is positively correlated with wolverine distribution [52], [53] and genetic differentiation [54], underlining the sensitivity of wolverines to climate change. Mitochondrial DNA (mtDNA) studies of this species have revealed strong genetic structure over small geographic scales, reflecting female philopatry (e.g. "
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    ABSTRACT: Interglacial-glacial cycles of the Quaternary are widely recognized in shaping phylogeographic structure. Patterns from cold adapted species can be especially informative - in particular, uncovering additional glacial refugia, identifying likely recolonization patterns, and increasing our understanding of species' responses to climate change. We investigated phylogenetic structure of the wolverine, a wide-ranging cold adapted carnivore, using a 318 bp of the mitochondrial DNA control region for 983 wolverines (n = 209 this study, n = 774 from GenBank) from across their full Holarctic distribution. Bayesian phylogenetic tree reconstruction and the distribution of observed pairwise haplotype differences (mismatch distribution) provided evidence of a single rapid population expansion across the wolverine's Holarctic range. Even though molecular evidence corroborated a single refugium, significant subdivisions of population genetic structure (0.01< ΦST <0.99, P<0.05) were detected. Pairwise ΦST estimates separated Scandinavia from Russia and Mongolia, and identified five main divisions within North America - the Central Arctic, a western region, an eastern region consisting of Ontario and Quebec/Labrador, Manitoba, and California. These data are in contrast to the nearly panmictic structure observed in northwestern North America using nuclear microsatellites, but largely support the nuclear DNA separation of contemporary Manitoba and Ontario wolverines from northern populations. Historic samples (c. 1900) from the functionally extirpated eastern population of Quebec/Labrador displayed genetic similarities to contemporary Ontario wolverines. To understand these divergence patterns, four hypotheses were tested using Approximate Bayesian Computation (ABC). The most supported hypothesis was a single Beringia incursion during the last glacial maximum that established the northwestern population, followed by a west-to-east colonization during the Holocene. This pattern is suggestive of colonization occurring in accordance with glacial retreat, and supports expansion from a single refugium. These data are significant relative to current discussions on the conservation status of this species across its range.
    PLoS ONE 12/2013; 8(12):e83837. DOI:10.1371/journal.pone.0083837 · 3.23 Impact Factor
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