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By regulating successional dynamics in Canada's boreal forest, fires can affect the distribution of the Threatened woodland caribou (Rangifer tarandus caribou (Gmelin, 1788)). Caribou tend to avoid areas burned within the last 40 years; however, few studies have compared pre-fire and post-fire caribou observations. In this study, we used caribou GPS locations from the Boreal Shield of Saskatchewan, Canada, to assess the short-term response of caribou to areas that burned while they were collared (hereafter recent burns). We used a 'before-after, control-impact' design to compare the overlap of pre-fire and post-fire seasonal home ranges to the overlap of year-to-year seasonal home ranges. Caribou rarely encountered recent burns and when they did, they adjusted their space use in variable and complex ways that were largely indistinguishable from regular, interannual variation. Caribou tended to reduce use of recent burns in summer-autumn and winter, but not during the calving season, in some cases shifting their home range to incorporate more burned habitat. We conclude that recently burned areas ( Key words: boreal forest, caribou, fire, habitat disturbance, home range, Rangifer tarandus, space use. En regulant la dynamique de succession dans la foret boreale du Canada, le feu peut influer sur la repartition du caribou des bois (Rangifer tarandus caribou (Gmelin, 1788)), une espece menacee. Si les caribous ont tendance a eviter les secteurs brules au cours des 40 annees precedentes, peu d'etudes ont toutefois compare les observations de caribous avant et apres un feu. Nous utilisons des emplacements de caribous obtenus par GPS dans le bouclier boreal de la Saskatchewan (Canada) pour evaluer la reaction a court terme des caribous a des zones brulees alors qu'ils etaient dotes d'un collier (des<< brulis recents >>). Nous employons un schema<>pour comparer le chevauchement des domaines vitaux saisonniers avant et apres le feu au chevauchement des domaines vitaux saisonniers d'une annee a l'autre. La frequence des rencontres de brulis recents par des caribous est faible et, quand elles se produisent, les caribous ajustent leur utilisation de l'espace de manieres variees et complexes qui sont difficiles a departager de la variation interannuelle normale. Les caribous ont tendance a moins utiliser les brulis recents en ete-automne et en hiver, mais non durant la saison de mise bas, deplacant dans certains cas leur domaine vital pour y integrer plus d'habitat brule. Nous concluons que les brulis recents ( Mots-cles: foret boreale, caribou, feu, perturbation de 1'habitat, domaine vital, Rangifer tarandus, utilisation de l'e space., Introduction Global ecosystems are experiencing accelerated rates of change as the frequency, extent, and intensity of natural and human disturbance increases (IPBES 2019). Habitat disturbance is contributing to population declines [...]

Habitat selection is a behavioural process that ultimately affects animal fitness. Forage availability and predation risk are often studied in the context of habitat selection for large ungulates, while other biological and environmental factors such as insect harassment and footing are less studied. Here we examine trade-offs in summer habitat selection between forage availability for wood bison (Bison bison athabascae Rhoads, 1898) with that of biting-fly harassment and soil firmness, which affects activity budgets and predation risk, respectively, and contrast this to winter when flies are absent and soils frozen. Using path analysis, we demonstrate that graminoid availability was not related to habitat selection in summer, but was positively related to habitat selection in winter. Habitat selection in summer was negatively related to biting-fly abundance and positively related to firmer footing. Our results suggest that bison observe trade-offs in summer between maximizing forage intake and minimizing harassment from that of biting flies, while avoiding areas of soft substrates that affect locomotion and vulnerability to predators. In contrast, during the winter, bison focus on areas with greater graminoid availability. Although forage is a key aspect of habitat selection, our results illustrate the importance of considering direct and indirect effects of multiple biological and environmental factors related to ungulate habitat selection. Key words: wood bison, Bison bison athabascae, ungulate, habitat selection, forage, insect harassment, footing. La selection d'habitat est un processus comportemental qui, ultimement, influence l'aptitude des animaux. La disponibilite de nourriture et le risque de predation sont souvent etudies dans le contexte de la selection d'habitat pour les grands ongules, alors que d'autres facteurs biologiques ou environnementaux, comme le harcelement par les insectes et la qualite de la surface du sol, le sont moins. Nous examinons les compromis dans le processus de selection d'habitat en ete par le bison des bois (Bison bison athabascae Rhoads, 1898) entre la disponibilite de nourriture et le harcelement par des mouches piqueuses et la fermete du sol, qui ont une incidence, respectivement, sur les budgets d'activite et le risque de predation, et les comparons a ce qui se passe l'hiver, quand les mouches sont absentes et le sol est gele. En utilisant l'analyse causale, nous demontrons que la disponibilite de graminoides n'est pas reliee a la selection d'habitat en ete, mais presente une relation positive avec la selection en hiver. La selection d'habitat en ete est negativement reliee a l'abondance de mouches piqueuses et positivement reliee a la fermete de la surface du sol. Nos resultats donnent a penser que les bisons font des compromis en ete entre la maximisation de l'ingestion de nourriture et la minimisation du harcelement par les mouches piqueuses, tout en evitant les zones de substrats mous qui influencent leur locomotion et leur vulnerabilite aux predateurs. En comparaison, durant l'hiver, les bisons se concentrent sur des zones caracterisees par une plus grande disponibilite de nourriture. Si la nourriture est un aspect cle de la selection d'habitat, nos resultats illustrent l'importance de tenir compte des effets directs et indirects de plusieurs facteurs biologiques et environnementaux associes a la selection d'habitat chez les ongules. [Traduit par la Redaction] Mots-cles : bison des bois, Bison bison athabascae, ongule, selection d'habitat, nourriture, harcelement par les insectes, surface du sol., Introduction Habitat selection is a behavioural process by which animals select resources, thereby affecting acquisition and competition for food, mates, reproductive success, and ultimately fitness (Schaefer and Messier 1995; Dussault [...]

Human-mediated disturbances can lead to novel environmental features that can affect native biota beyond simple habitat loss. In boreal forests of western Canada, linear features (LFs; e.g., pipelines, seismic lines, and roads) are known to alter behaviour, movements, and interactions among species. Understanding LF impacts on native species has therefore been a management priority. Here, we investigate how LFs affect the spatial behaviour of wood bison (Bison bison athabascae Rhoads, 1898), which are designated as 'threatened' in Canada. Using data collected from the Ronald Lake population in northeastern Alberta, we assessed how LFs influenced habitat selection and movement of bison by testing support among three hypotheses explaining whether LFs (i) increased forage availability, (ii) enhanced movement efficiency, or (iii) increased predation risk. Results supported the movement efficiency hypothesis as bison were generally ambivalent toward LFs, showing weak selection or avoidance depending on land-cover type, but moved slightly faster when on them. These findings contrast with avoidance behaviours reported for sympatric woodland caribou (Rangifer tarandus caribou (Gmelin, 1788)), which are also 'threatened.' Our results should inform critical habitat decisions for wood bison, but we caution that further research is needed to understand the effects of LFs on bison demography. Key words: wood bison, Bison bison athabascae, linear features, boreal forest, seismic lines, anthropogenic disturbance, critical habitat. Les perturbations d'origine humaine peuvent mener a de nouveaux elements du milieu qui peuvent avoir des effets sur le biote indigene autres que la simple disparition d'habitat. Dans les forets boreales de l'Ouest canadien, il est etabli que les elements lineaires (EL; p. ex. pipelines, lignes sismiques et routes) modifient les comportements, les deplacements et les interactions d'especes. La comprehension des impacts d'EL sur les especes indigenes constitue donc une priorite de gestion. Nous examinons l'incidence d'EL sur le comportement spatial des bisons des bois (Bison bison athabascae Rhoads, 1898), qui figurent sur la liste des especes << menacees >> au Canada. En utilisant des donnees obtenues de la population du lac Ronald, dans le nord-est de l'Alberta, nous avons evalue l'influence des EL sur la selection d'habitats et les deplacements des bisons en nous penchant sur les observations qui appuieraient trois hypotheses, a savoir que les EL (i) accroissent la disponibilite de fourrage, (ii) accroissent l'efficacite des deplacements ou (iii) accroissent les risques de predation. Les resultats appuient l'hypothese de l'efficacite des deplacements, puisque les bisons sont generalement ambivalents en ce qui concerne les EL, presentant une faible selection ou un faible evitement selon le type de couverture, mais se deplacant legerement plus vite quand ils sont dans ces zones. Ces constatations different des comportements d'evitement signales pour les caribous des bois (Rangifer tarandus caribou (Gmelin, 1788)) sympatriques, qui sont egalement << menaces >>. Nos resultats devraient etre pris en consideration dans la prise de decisions concernant les habitats essentiels pour le bison des bois, mais nous tenons a souligner que d'autres travaux sont necessaires pour comprendre les effets des EL sur la demographie des bisons. [Traduit par la Redaction] Mots-cles : bison des bois, Bison bison athabascae, elements lineaires, foret boreale, lignes sismiques, perturbation d'origine humaine, habitat essentiel., Introduction Across the globe, human activities are altering natural landscapes at rates and spatial scales exceeding those associated with natural disturbance regimes (Seidl et al. 2016). In addition to habitat [...]

Seasonal food habits and activity patterns were examined for grizzly bears (Ursus arctos) in west-central Alberta, Canada, to better understand habitat requirements in a threatened population. Food habits were based on an analysis of 665 feces collected from 18 grizzly bears between April and October 2001-2003. Trends in the use of foods were comparable to those of other central Rocky Mountain populations, with minor differences likely reflecting regional habitat and forage availability. Five activities (bedding, sweet vetch digging, insect feeding, frugivory, and ungulate kills) were identified for each of 1,032 field-visited global positioning system radiotelemetry locations from 9 female grizzly bears. We predicted the probability of each activity during relevant periods by time of day (crepuscular, diumal, and nocturnal) and habitat. Selection ratios were used to assess which habitat and time periods were selected. Activity patterns changed considerably over a 24-h period, with foraging activities occurring mostly during diurnal and crepuscular periods and bedding at night. Habitats were important predictors of activity. Forested areas were selected for bedding areas, whereas digging, insect-foraging, and frugivory activities were associated with herbaceous, recently disturbed forest and open-canopy forests. We suggest that researchers consider behavior and time of day in analyses of habitat selection to improve explanations of habitat use and mechanisms of selection. Key words: activity, Alberta, conservation, diet, foraging, grizzly bear, Ursus arctos