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Long ME, Stewart KM, Shoemaker KT, Reich H, Lackey CW, Beckmann JP. Selection of den sites and chronology of denning by black bears in the eastern Sierra Nevada and western Great Basin. Ecol Evol 2024; 14:e11689. [PMID: 38988341 PMCID: PMC11236437 DOI: 10.1002/ece3.11689] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2023] [Revised: 06/11/2024] [Accepted: 06/20/2024] [Indexed: 07/12/2024] Open
Abstract
Use of dens during winter is an important strategy for American black bears (Ursus americanus) for both energy conservation and reproduction; and occupancy of suitable den sites has implications for reproductive fitness. Denning strategies may change as a result of changing climatic conditions and habitat loss. Black bears occupy arid environments in the eastern Sierra Nevada and the western ranges of the Great Basin Ecosystem. Our objectives were to identify: (1) which physical characteristics of habitat influenced selection of den sites at multiple spatial scales and (2) which environmental factors influenced timing of entrance and exit of dens by females and males. We evaluated selection of den sites by black bears at three spatial scales (300, 1000, and 4000 m) from 2011 to 2022. Terrain ruggedness was important for selection of den sites at all spatial scales. Within a 300-m buffer from the den, bears selected den sites with rugged terrain, lower horizontal visibility, and greater canopy cover, resulting in more concealment and protection than that of the surrounding environment. Within 1000- and 4000-m buffers around each den, bears selected den sites with rugged terrain, northern aspects, and steep slopes. At the 4000-m scale, we observed interactions between sex with slope and distance to roads; females selected den sites on steeper slopes and closer to roads than did males. Females remained in the dens longer than males by entering earlier in the autumn and exiting later in the spring. Male bears exited their dens earlier with increasing consecutive days above freezing temperatures, but that relationship was weak for females. Knowing what characteristics are important for selection of den sites, and influence timing of denning, will be important for understanding how shifting climatic patterns will affect bears, particularly in arid environments that may be prone to wider fluctuations in climatic drivers of denning in the future.
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Affiliation(s)
- Morgan E. Long
- Ecology Evolution and Conservation Biology Graduate Program and Department of Natural Resources and Environmental ScienceUniversity of NevadaRenoNevadaUSA
| | - Kelley M. Stewart
- Ecology Evolution and Conservation Biology Graduate Program and Department of Natural Resources and Environmental ScienceUniversity of NevadaRenoNevadaUSA
| | - Kevin T. Shoemaker
- Ecology Evolution and Conservation Biology Graduate Program and Department of Natural Resources and Environmental ScienceUniversity of NevadaRenoNevadaUSA
| | | | | | - Jon P. Beckmann
- Wildlife Conservation SocietyBozemanMontanaUSA
- Present address:
Kansas Department of Wildlife and ParksPrattKansasUSA
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Poirier M, Gauthier G, Domine F, Fauteux D. Lemming winter habitat: the quest for warm and soft snow. Oecologia 2023:10.1007/s00442-023-05385-y. [PMID: 37351629 DOI: 10.1007/s00442-023-05385-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Accepted: 05/08/2023] [Indexed: 06/24/2023]
Abstract
During the cold arctic winter, small mammals like lemmings seek refuge inside the snowpack to keep warm and they dig tunnels in the basal snow layer, usually formed of a soft depth hoar, to find vegetation on which they feed. The snowpack, however, is a heterogenous medium and lemmings should use habitats where snow properties favor their survival and winter reproduction. We determined the impact of snow physical properties on lemming habitat use and reproduction in winter by sampling their winter nests for 13 years and snow properties for 6 years across 4 different habitats (mesic, riparian, shrubland, and wetland) on Bylot Island in the Canadian High Arctic. We found that lemmings use riparian habitat most intensively because snow accumulates more rapidly, the snowpack is the deepest and temperature of the basal snow layer is the highest in this habitat. However, in the deepest snowpacks, the basal depth hoar layer was denser and less developed than in habitats with shallower snowpacks, and those conditions were negatively related to lemming reproduction in winter. Shrubland appeared a habitat of moderate quality for lemmings as it favored a soft basal snow layer and a deep snowpack compared with mesic and wetland, but snow conditions in this habitat critically depend on weather conditions at the beginning of the winter. With climate change, a hardening of the basal layer of the snowpack and a delay in snow accumulation are expected, which could negatively affect the winter habitat of lemmings and be detrimental to their populations.
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Affiliation(s)
- Mathilde Poirier
- Centre d'Études Nordiques, Université Laval, Pavillon Abitibi-Price, 2405, rue de la Terrasse, Québec, QC, Canada.
- Department of Biology, Université Laval, 1045 av. de la Médecine, Québec, QC, Canada.
- Takuvik Joint International Laboratory, Université Laval (Canada) and CNRS-INSU (France), 1045 av. de la Médecine, Québec, QC, Canada.
| | - Gilles Gauthier
- Centre d'Études Nordiques, Université Laval, Pavillon Abitibi-Price, 2405, rue de la Terrasse, Québec, QC, Canada
- Department of Biology, Université Laval, 1045 av. de la Médecine, Québec, QC, Canada
| | - Florent Domine
- Centre d'Études Nordiques, Université Laval, Pavillon Abitibi-Price, 2405, rue de la Terrasse, Québec, QC, Canada
- Takuvik Joint International Laboratory, Université Laval (Canada) and CNRS-INSU (France), 1045 av. de la Médecine, Québec, QC, Canada
- Department of Chemistry, Université Laval, 1045 av. de la Médecine, Québec, QC, Canada
| | - Dominique Fauteux
- Centre d'Études Nordiques, Université Laval, Pavillon Abitibi-Price, 2405, rue de la Terrasse, Québec, QC, Canada
- Centre for Arctic Knowledge and Exploration, Canadian Museum of Nature, Station D, P.O. Box 3443, Ottawa, ON, Canada
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Sorum MS, Cameron MD, Crupi A, Sage GK, Talbot SL, Hilderbrand GV, Joly K. Pronounced brown bear aggregation along anadromous streams in interior Alaska. WILDLIFE BIOLOGY 2023. [DOI: 10.1002/wlb3.01057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/03/2023]
Affiliation(s)
- Mathew S. Sorum
- Gates of the Arctic National Park and Preserve, National Park Service Fairbanks Alaska USA
| | - Matthew D. Cameron
- Gates of the Arctic National Park and Preserve, National Park Service Fairbanks Alaska USA
| | | | - George K. Sage
- Far Northwestern Inst. of Art and Science, Alaska Office Alaska USA
| | - Sandra L. Talbot
- Far Northwestern Inst. of Art and Science, Alaska Office Alaska USA
| | | | - Kyle Joly
- Gates of the Arctic National Park and Preserve, National Park Service Fairbanks Alaska USA
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Swaminathan S, Sharp TR, Arun AS, Smith TS, Larsen R, Satyanarayan K, Seshamani G. Sloth bear maternal and resting den locations in eastern Karnataka. J Wildl Manage 2023. [DOI: 10.1002/jwmg.22360] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
| | - Thomas R. Sharp
- Wildlife SOS 406 East 300 South, No. 302 Salt Lake City UT 84111 USA
| | - Attur S. Arun
- Wildlife SOS, Bannerghatta Bear Rescue and Rehab Centre Bangalore 560083 India
| | - Tom S. Smith
- Brigham Young University 5050 Life Sciences Building Provo UT 84602 USA
| | - Randy Larsen
- Brigham Young University 5050 Life Sciences Building Provo UT 84602 USA
| | | | - Geeta Seshamani
- Wildlife SOS, Bannerghatta Bear Rescue and Rehab Centre Bangalore 560083 India
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Joly K, Cameron MD, Sorum MS, Gustine DD, Deacy W, Hilderbrand GV. Factors influencing Arctic brown bear annual home range sizes and limitations of home range analyses. URSUS 2022. [DOI: 10.2192/ursus-d-21-00015.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Affiliation(s)
- Kyle Joly
- National Park Service, Gates of the Arctic National Park and Preserve, 4175 Geist Road, Fairbanks, AK 99709, USA
| | - Matthew D. Cameron
- National Park Service, Gates of the Arctic National Park and Preserve, 4175 Geist Road, Fairbanks, AK 99709, USA
| | - Mathew S. Sorum
- National Park Service, Gates of the Arctic National Park and Preserve, 4175 Geist Road, Fairbanks, AK 99709, USA
| | - David D. Gustine
- U.S. Fish and Wildlife Service, Marine Mammals Management, Polar Bear Program, 1011 E. Tudor Road, Anchorage, AK 99503, USA
| | - William Deacy
- National Park Service, Arctic Inventory and Monitoring Program, 4175 Geist Road, Fairbanks, AK 99709, USA
| | - Grant V. Hilderbrand
- National Park Service, Alaska Regional Office, 240 W 5th Avenue, Anchorage, AK 99501, USA
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Thompson PR, Lewis MA, Edwards MA, Derocher AE. Time-dependent memory and individual variation in Arctic brown bears (Ursus arctos). MOVEMENT ECOLOGY 2022; 10:18. [PMID: 35410401 PMCID: PMC8996616 DOI: 10.1186/s40462-022-00319-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Accepted: 03/24/2022] [Indexed: 06/14/2023]
Abstract
BACKGROUND Animal movement modelling provides unique insight about how animals perceive their landscape and how this perception may influence space use. When coupled with data describing an animal's environment, ecologists can fit statistical models to location data to describe how spatial memory informs movement. METHODS We performed such an analysis on a population of brown bears (Ursus arctos) in the Canadian Arctic using a model incorporating time-dependent spatial memory patterns. Brown bear populations in the Arctic lie on the periphery of the species' range, and as a result endure harsh environmental conditions. In this kind of environment, effective use of memory to inform movement strategies could spell the difference between survival and mortality. RESULTS The model we fit tests four alternate hypotheses (some incorporating memory; some not) against each other, and we found a high degree of individual variation in how brown bears used memory. We found that 71% (15 of 21) of the bears used complex, time-dependent spatial memory to inform their movement decisions. CONCLUSIONS These results, coupled with existing knowledge on individual variation in the population, highlight the diversity of foraging strategies for Arctic brown bears while also displaying the inference that can be drawn from this innovative movement model.
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Affiliation(s)
- Peter R Thompson
- Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada.
| | - Mark A Lewis
- Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada
- Department of Mathematical and Statistical Sciences, University of Alberta, Edmonton, AB, Canada
| | - Mark A Edwards
- Mammalogy Department, Royal Alberta Museum, Edmonton, AB, Canada
- Department of Renewable Resources, University of Alberta, Edmonton, AB, Canada
| | - Andrew E Derocher
- Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada
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Crupi AP, Gregovich DP, White KS. Steep and deep: Terrain and climate factors explain brown bear (Ursus arctos) alpine den site selection to guide heli-skiing management. PLoS One 2020; 15:e0238711. [PMID: 32966287 PMCID: PMC7511016 DOI: 10.1371/journal.pone.0238711] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Accepted: 08/21/2020] [Indexed: 11/28/2022] Open
Abstract
Winter recreation and tourism continue to expand worldwide, and where these activities overlap with valuable wildlife habitat, there is greater potential for conservation concerns. Wildlife populations can be particularly vulnerable to disturbance in alpine habitats as helicopters and snowmachines are increasingly used to access remote backcountry terrain. Brown bears (Ursus arctos) have adapted hibernation strategies to survive this period when resources and energy reserves are limited, and disturbance could negatively impact fitness and survival. To help identify areas of potential conflict between helicopter skiing and denning brown bears in Alaska, we developed a model to predict alpine denning habitat and an associated data-based framework for mitigating disturbance activities. Following den emergence in spring, we conducted three annual aerial surveys (2015-2017) and used locations from three GPS-collared bears (2008-2014) to identify 89 brown bear dens above the forest line. We evaluated brown bear den site selection of land cover, terrain, and climate factors using resource selection function (RSF) models. Our top model supported the hypothesis that bears selected dens based on terrain and climate factors that maximized thermal efficiency. Brown bears selected den sites characterized by steep slopes at moderate elevations in smooth, well-drained topographies that promoted vegetation and deep snow. We used the RSF model to map relative probability of den selection and found 85% of dens occurred within terrain predicted as prime denning habitat. Brown bear exposure to helicopter disturbance was evident as moderate to high intensities of helicopter flight tracking data overlapped prime denning habitat, and we quantified where the risk of these impact was greatest. We also documented evidence of late season den abandonment due to disturbance from helicopter skiing. The results from this study provide valuable insights into bear denning habitat requirements in subalpine and alpine landscapes. Our quantitative framework can be used to support conservation planning for winter recreation industries operating in habitats occupied by denning brown bears.
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Affiliation(s)
- Anthony P. Crupi
- Division of Wildlife Conservation, Alaska Department of Fish and Game, Douglas, Alaska, United States of America
| | - David P. Gregovich
- Division of Wildlife Conservation, Alaska Department of Fish and Game, Douglas, Alaska, United States of America
| | - Kevin S. White
- Division of Wildlife Conservation, Alaska Department of Fish and Game, Douglas, Alaska, United States of America
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Shiratsuru S, Friebe A, Swenson JE, Zedrosser A. Room without a view-Den excavation in relation to body size in brown bears. Ecol Evol 2020; 10:8044-8054. [PMID: 32788960 PMCID: PMC7417226 DOI: 10.1002/ece3.6371] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Revised: 04/23/2020] [Accepted: 04/24/2020] [Indexed: 11/22/2022] Open
Abstract
Hibernation is an adaptive strategy to survive harsh winter conditions and food shortage. The use of well-insulated winter dens helps animals minimize energy loss during hibernation. Brown bears (Ursus arctos) commonly use excavated dens for hibernation. Physical attributes of excavated dens are expected to impact the bear's heat retention and energy conservation. The objective of this study was to examine the determinants of cavity size of excavated dens and the impact of physical attributes of excavated dens on energy conservation in hibernating bears, hypothesizing that bears excavate dens in a way to minimize heat loss and optimize energy conservation during hibernation. We predicted that den cavity size would be determined by the bear's body size and that older bears would excavate better-fitting cavities to minimize heat loss, due to their previous experience. We further predicted that physical attributes of excavated dens would affect the bears' posthibernation body condition. Our results revealed that bears excavated a den cavity in relation to their body size, regardless of sex, and that older bears tended to excavate better-fitting den cavities compared to young bears, as we expected. Older bears excavated better-fitting den cavities, suggesting a potentially experience-based shift with age in den-excavation behavior and an optimum cavity size relative to a bear's body size. Our key finding is that insulation of excavated dens provided by wall/rood thickness and bedding materials had a significant positive effect on bears' posthibernation body condition. We believe that our study provides new insight into how not only the quality of denning habitat, but also the quality of dens may affect hibernating animals, by presenting a potential adaptive aspect of den preparation (age effect on efficiency in den excavation) and effect of den attributes on the posthibernation body condition of brown bears.
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Affiliation(s)
| | - Andrea Friebe
- Scandinavian Brown Bear Research ProjectOrsaSweden
- Norwegian Institute for Nature ResearchTrondheimNorway
| | - Jon E. Swenson
- Faculty of Environmental Sciences and Natural Resource ManagementNorwegian University of Life SciencesÅsNorway
| | - Andreas Zedrosser
- Department of Natural Sciences and Environmental HealthUniversity of South‐Eastern NorwayTelemarkNorway
- Department of Integrative BiologyInstitute of Wildlife Biology and Game ManagementUniversity of Natural Resources and Life SciencesViennaAustria
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González-Bernardo E, Russo LF, Valderrábano E, Fernández Á, Penteriani V. Denning in brown bears. Ecol Evol 2020; 10:6844-6862. [PMID: 32724555 PMCID: PMC7381752 DOI: 10.1002/ece3.6372] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 04/16/2020] [Accepted: 04/22/2020] [Indexed: 12/12/2022] Open
Abstract
Hibernation represents an adaptation for coping with unfavorable environmental conditions. For brown bears Ursus arctos, hibernation is a critical period as pronounced temporal reductions in several physiological functions occur.Here, we review the three main aspects of brown bear denning: (1) den chronology, (2) den characteristics, and (3) hibernation physiology in order to identify (a) proximate and ultimate factors of hibernation as well as (b) research gaps and conservation priorities.Den chronology, which varies by sex and reproductive status, depends on environmental factors, such as snow, temperature, food availability, and den altitude. Significant variation in hibernation across latitudes occurs for both den entry and exit.The choice of a den and its surroundings may affect individual fitness, for example, loss of offspring and excessive energy consumption. Den selection is the result of broad- and fine-scale habitat selection, mainly linked to den insulation, remoteness, and availability of food in the surroundings of the den location.Hibernation is a metabolic challenge for the brown bears, in which a series of physiological adaptations in tissues and organs enable survival under nutritional deprivation, maintain high levels of lipids, preserve muscle, and bone and prevent cardiovascular pathologies such as atherosclerosis. It is important to understand: (a) proximate and ultimate factors in denning behavior and the difference between actual drivers of hibernation (i.e., factors to which bears directly respond) and their correlates; (b) how changes in climatic factors might affect the ability of bears to face global climate change and the human-mediated changes in food availability; (c) hyperphagia (period in which brown bears accumulate fat reserves), predenning and denning periods, including for those populations in which bears do not hibernate every year; and (d) how to approach the study of bear denning merging insights from different perspectives, that is, physiology, ecology, and behavior.
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Affiliation(s)
- Enrique González-Bernardo
- Research Unit of Biodiversity (UMIB, CSIC-UO-PA) Mieres Spain
- Pyrenean Institute of Ecology (IPE-CSIC) Zaragoza Spain
| | - Luca Francesco Russo
- Research Unit of Biodiversity (UMIB, CSIC-UO-PA) Mieres Spain
- Department of Biosciences and the Territory Università degli Studi del Molise Pesche Italy
| | - Esther Valderrábano
- COPAR Research Group Faculty of Veterinary University of Santiago de Compostela Lugo Spain
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