High-quality habitats for caribou (Rangifer tarandus (L., 1758)) are associated primarily with lichens, but lichens alone fail to satisfy summer nutritional requirements. To evaluate the summer forage value of plant communities across northeastern British Columbia (BC), where populations of northern and boreal ecotypes of caribou are declining, we observed foraging by tame, female caribou. We compared diet composition with forage abundance to determine forage selection and to quantify forage availability. Deciduous shrubs, not lichens, largely dominated summer diets. Caribou were highly selective foragers, with 28 species comprising 78% of diets. Caribou avoided ≥50% of understory vegetation in all communities, especially conifers, evergreen shrubs, mosses, and two genera of terrestrial lichens. Availability of accepted forage (species not avoided) was strongly heterogeneous across landscapes. Alpine shrub areas and mid-elevation spruce-fir stands in the mountains, as well as treed rich fens and white spruce communities in the boreal forests, provided the greatest quantities of accepted forage for caribou. Dry alpine sites and unproductive black spruce communities provided the least accepted forage. Our work has direct implications to caribou conservation by contributing to a greater understanding of the forage value of summer habitats, with implications to habitat selection, seasonal movements, and distribution ecology.Key words: Rangifer tarandus caribou, woodland caribou, diet composition, alpine, boreal forest, food selection, foraging.Résumé : Si les habitats de grande qualité pour le caribou (Rangifer tarandus (L., 1758)) sont principalement associés aux lichens, ces derniers seuls ne peuvent satisfaire aux besoins alimentaires estivaux des caribous. Afin d'évaluer la valeur comme fourrage des communautés de plantes dans le nord-est de la Colombie-Britannique (C.-B.), où les populations des écotypes nordique et boréal de caribous sont en baisse, nous avons observé l'approvisionnement de caribous femelles apprivoisés. Nous avons comparé la composition du régime alimentaire à l'abondance de fourrage afin de déterminer quels types de fourrage sont sélectionnés et de quantifier la disponibilité de fourrage. Les arbustes feuillus, et non les lichens, constituaient une portion prépondérante des régimes alimentaires estivaux. Les caribous s'approvisionnaient de manière très sélective, 28 espèces constituant 78 % de leurs régimes alimentaires. Les caribous évitaient ≥50 % de la végétation du sous-bois dans toutes les communautés, particulièrement les arbres et arbustes conifères, les mousses et deux genres de lichens terrestres. La disponibilité de fourrages acceptés (espèces non évitées) était très hétérogène dans les différents paysages. Les zones arbustives alpines et les peuplements d'épinettes et de sapins d'élévation moyenne dans les montagnes, ainsi que les tourbières boisées riches et les communautés d'épinettes blanches dans les forêts boréales offraient les plus grandes quantités de fourrage ac...

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Information garnered from the capture and handling of free-ranging animals helps advance understanding of wildlife ecology and can aid in decisions on wildlife management. Unfortunately, animals may experience increased levels of stress, injuries, and death resulting from captures (e.g., exertional myopathy, trauma). Partial sedation is a technique proposed to alleviate stress in animals during capture, yet efficacy of partial sedation for reducing stress and promoting survival post-capture remains unclear. We evaluated the effects of partial sedation on physiological, biochemical, and behavioral indicators of acute stress and probability of survival post-capture for mule deer (Odocoileus hemionus) that were captured via helicopter net-gunning in the eastern Greater Yellowstone Ecosystem, Wyoming, USA. We administered 10-30 mg of midazolam and 15 mg of azaperone intramuscularly (IM) to 32 mule deer in 2016 and 53 mule deer in 2017, and maintained a control group (captured but not sedated) of 38 mule deer in 2016 and 54 mule deer in 2017. To evaluate indicators of acute stress, we measured heart rate, blood-oxygen saturation, body temperature, respiration rate, and levels of serum cortisol. We recorded number of kicks and vocalizations of deer during handling and evaluated behavior during release. We also measured levels of fecal glucocorticoids as an indicator of baseline stress. Midazolam and azaperone did not reduce physiological, biochemical, or behavioral indicators of acute stress or influence probability of survival post-capture. Mule deer that were administered midazolam and azaperone, however, were more likely to hesitate, stumble or fall, and walk during release compared with individuals in the control group, which were more likely to trot, stot, or run without stumbling or falling. Our findings suggest that midazolam (10-30 mg IM) and azaperone (15 mg IM) may not yield physiological or demographic benefits for captured mule deer as previously assumed and may pose adverse effects that can complicate safety for captured animals, including drug-induced lethargy. Although we failed to find efficacy of midazolam and azaperone

Food quality and availability, when combined with energetic demands in seasonal environments, shape resource acquisition and allocation by animals and hold consequences for life‐history strategies. In long‐lived species with extensive maternal care, regulation of somatic reserves of energy and protein can occur in a risk‐sensitive manner, wherein resources are preferentially allocated to support survival at the cost of investment in reproduction. We investigated how Rocky Mountain bighorn sheep (Ovis canadensis), an alpine mammal in a highly seasonal environment, allocates somatic reserves across seasons. In accordance with the hypothesis of risk‐sensitive resource allocation, we expected accretion and catabolism of somatic reserves to be regulated relative to preseason nutritional state, reproductive state, and variation among populations in accordance with local environmental conditions. To test that hypothesis, we monitored seasonal changes in percent ingesta‐free body fat (IFBFat) and ingesta‐free, fat‐free body mass (IFFFBMass) in three populations of bighorn sheep in northwest Wyoming between 2015 and 2019 through repeated captures of female sheep in December and March of each year in a longitudinal study design. Regulation of somatic reserves was risk‐sensitive and varied relative to the amount of somatic reserves an animal had at the beginning of the season. Regulation of fat reserves was sensitive to reproductive state and differed by population, particularly over the summer. In one population with low rates of recruitment of young, sheep that recruited offspring lost fat over the summer in contrast to the other two populations where sheep that recruited gained fat. And yet, all populations exhibited similar changes in fat catabolism and risk sensitivity over winter. The magnitude of body fat and mass change across seasons may be indicative of sufficiency of seasonal ranges to meet energetic demands of survival and reproduction. Risk‐sensitive allocation of resources was pervasive, suggesting nutritional underpinnings are foundational to behavior, vital rates, and, ultimately, population dynamics. For species living in alpine environments, risk‐sensitive resource allocation may be essential to balance investment in reproduction with ensuring survival.

1. Energy stores and migration are important adaptations for animals in seasonal environments, but their roles may vary relative to an animal's endogenous and exogenous environment. In partially migratory populations, migrants and residents experience different seasonal environments; thus, the influence of energy stores on survival may differ relative to migratory tactic, with potential consequences to survival and fitness.2. Using data from Sierra Nevada bighorn sheep (Ovis canadensis sierrae; hereafter, Sierra bighorn), we tested the hypothesis that body fat (energy stores) buffers animals against their environment, but that buffering capacity differs across environments experienced by high-elevation residents (using a single range yearround), traditional migrants (making 1 round-trip movement between high-and low-elevation ranges during winter) and vacillating migrants (making ≥2 round trips between high-and low-elevation ranges during winter). We predicted that: for animals with high levels of body fat, survival would be high regardless of migratory tactic; residents would require larger stores of body fat to survive than migrants; energy stores would be least influential to survival for vacillating migrants.3. High levels of body fat in autumn (≥14% for females and ≥19% for males) largely buffered animals against harsh environments (survival >0.90) regardless of migratory tactic. At lower levels of body fat, traditional migrants had higher survival than residents. Vacillating migrants exhibited nearly 100% survival with no detectable effect of body fat on survival. 4. Collectively, these results support the hypothesis that body fat buffers animals against harsh environments but that the buffering capacity differed relative to the environment and highly flexible behaviours (i.e. vacillating migration) can allow animals to decouple survival from body fat. 5. Our work reveals that synergies between physiological and behavioural adaptations of animals in highly seasonal environments carry potential fitness consequences for individuals and demographic consequences for populations.