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Tschritter CM, van Coeverden de Groot P, Branigan M, Dyck M, Sun Z, Jenkins E, Buhler K, Lougheed SC. The geographic distribution, and the biotic and abiotic predictors of select zoonotic pathogen detections in Canadian polar bears. Sci Rep 2024; 14:12027. [PMID: 38797747 PMCID: PMC11128453 DOI: 10.1038/s41598-024-62800-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Accepted: 05/21/2024] [Indexed: 05/29/2024] Open
Abstract
Increasing Arctic temperatures are facilitating the northward expansion of more southerly hosts, vectors, and pathogens, exposing naïve populations to pathogens not typical at northern latitudes. To understand such rapidly changing host-pathogen dynamics, we need sensitive and robust surveillance tools. Here, we use a novel multiplexed magnetic-capture and droplet digital PCR (ddPCR) tool to assess a sentinel Arctic species, the polar bear (Ursus maritimus; n = 68), for the presence of five zoonotic pathogens (Erysipelothrix rhusiopathiae, Francisella tularensis, Mycobacterium tuberculosis complex, Toxoplasma gondii and Trichinella spp.), and observe associations between pathogen presence and biotic and abiotic predictors. We made two novel detections: the first detection of a Mycobacterium tuberculosis complex member in Arctic wildlife and the first of E. rhusiopathiae in a polar bear. We found a prevalence of 37% for E. rhusiopathiae, 16% for F. tularensis, 29% for Mycobacterium tuberculosis complex, 18% for T. gondii, and 75% for Trichinella spp. We also identify associations with bear age (Trichinella spp.), harvest season (F. tularensis and MTBC), and human settlements (E. rhusiopathiae, F. tularensis, MTBC, and Trichinella spp.). We demonstrate that monitoring a sentinel species, the polar bear, could be a powerful tool in disease surveillance and highlight the need to better characterize pathogen distributions and diversity in the Arctic.
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Affiliation(s)
| | | | - Marsha Branigan
- Department of Environment and Climate Change, Government of the Northwest Territories, Inuvik, Northwest Territories, Canada
| | - Markus Dyck
- Department of Environment, Government of Nunavut, Igloolik, NT, Canada
| | - Zhengxin Sun
- Department of Biology, Queen's University, Kingston, ON, Canada
| | - Emily Jenkins
- Western College of Veterinary Medicine (WCVM), Saskatoon, SK, Canada
| | - Kayla Buhler
- Western College of Veterinary Medicine (WCVM), Saskatoon, SK, Canada
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2
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Tschritter CM, V. C. de Groot P, Branigan M, Dyck M, Sun Z, Lougheed SC. A new multiplexed magnetic capture-Droplet digital PCR tool for monitoring wildlife population health and pathogen surveillance. Ecol Evol 2023; 13:e10655. [PMID: 37915804 PMCID: PMC10616740 DOI: 10.1002/ece3.10655] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Accepted: 10/09/2023] [Indexed: 11/03/2023] Open
Abstract
Anthropogenic stressors are exacerbating the emergence and spread of pathogens worldwide. In regions like the Arctic, where ecosystems are particularly susceptible, marked changes are predicted in regional diversity, intensity, and patterns of infectious diseases. To understand such rapidly changing host-pathogen dynamics and mitigate the impacts of novel pathogens, we need sensitive disease surveillance tools. We developed and validated a novel multiplexed, magnetic capture, and ddPCR tool for the surveillance of multiple pathogens in polar bears, a sentinel species that is considered susceptible to climate change and other stressors with a pan-Arctic distribution. Through sequence-specific magnetic capture, we concentrated five target template sequences from three zoonotic bacteria (Erysipelothrix rhusiopathiae, Francisella tularensis, and Mycobacterium tuberculosis complex) and two parasitic (Toxoplasma gondii and Trichinella spp.) pathogens from large quantities (<100 g) of host tissue. We then designed and validated two multiplexed probe-based ddPCR assays for the amplification and detection of the low-concentration target DNA. Validations used 48 polar bear tissues (muscle and liver). We detected 14, 1, 3, 4, and 22 tissue positives for E. rhusiopathiae, F. tularensis, M. tuberculosis complex, T. gondii, and Trichinella spp., respectively. These multiplexed assays offer a rapid, specific tool for quantifying and monitoring the changing geographical and host distributions of pathogens relevant to human and animal health.
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Affiliation(s)
| | | | - Marsha Branigan
- Department of Environment and Natural ResourcesGovernment of the Northwest TerritoriesInuvikNorthwest TerritoriesCanada
| | - Markus Dyck
- Department of EnvironmentGovernment of NunavutIgloolikNunavutCanada
| | - Zhengxin Sun
- Department of BiologyQueen's UniversityKingstonOntarioCanada
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3
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Fry TL, Friedrichs KR, Ketz AC, Duncan C, Van Deelen TR, Goldberg TL, Atwood TC. Long-term assessment of relationships between changing environmental conditions and the physiology of southern Beaufort Sea polar bears (Ursus maritimus). GLOBAL CHANGE BIOLOGY 2023; 29:5524-5539. [PMID: 37503782 DOI: 10.1111/gcb.16883] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Revised: 06/28/2023] [Accepted: 06/30/2023] [Indexed: 07/29/2023]
Abstract
Climate change is influencing polar bear (Ursus maritimus) habitat, diet, and behavior but the effects of these changes on their physiology is not well understood. Blood-based biomarkers are used to assess the physiologic health of individuals but their usefulness for evaluating population health, especially as it relates to changing environmental conditions, has rarely been explored. We describe links between environmental conditions and physiologic functions of southern Beaufort Sea polar bears using data from blood samples collected from 1984 to 2018, a period marked by extensive environmental change. We evaluated associations between 13 physiologic biomarkers and circumpolar (Arctic oscillation index) and regional (wind patterns and ice-free days) environmental metrics and seasonal and demographic co-variates (age, sex, season, and year) known to affect polar bear ecology. We observed signs of dysregulation of water balance in polar bears following years with a lower annual Arctic oscillation index. In addition, liver enzyme values increased over time, which is suggestive of potential hepatocyte damage as the Arctic has warmed. Biomarkers of immune function increased with regional-scale wind patterns and the number of ice-free days over the Beaufort Sea continental shelf and were lower in years with a lower winter Arctic oscillation index, suggesting an increased allocation of energetic resources for immune processes under these conditions. We propose that the variation in polar bear immune and metabolic function is likely indicative of physiologic plasticity, a response that allows polar bears to remain in homeostasis even as they experience changes in nutrition and habitat in response to changing environments.
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Affiliation(s)
- Tricia L Fry
- School of Veterinary Medicine, University of Wisconsin, Madison, Wisconsin, USA
| | | | - Alison C Ketz
- Department of Forest and Wildlife Ecology, Wisconsin Cooperative Research Unit, University of Wisconsin, Madison, Wisconsin, USA
| | - Colleen Duncan
- Department of Microbiology, Immunology and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, Colorado, USA
| | - Timothy R Van Deelen
- Department of Forest and Wildlife Ecology, University of Wisconsin, Madison, Wisconsin, USA
| | - Tony L Goldberg
- School of Veterinary Medicine, University of Wisconsin, Madison, Wisconsin, USA
| | - Todd C Atwood
- U.S. Geological Survey, Alaska Science Center, Anchorage, Alaska, USA
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4
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Fry TL, Owens LA, Ketz AC, Atwood TC, Dunay E, Goldberg TL. Serum Virome of Southern Beaufort Sea polar bears ( Ursus maritimus) during a period of rapid climate change. CONSERVATION PHYSIOLOGY 2023; 11:coad054. [PMID: 39070777 PMCID: PMC10375943 DOI: 10.1093/conphys/coad054] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Revised: 06/02/2023] [Accepted: 07/07/2023] [Indexed: 07/30/2024]
Abstract
Climate change affects the behavior, physiology and life history of many Arctic wildlife species. It can also influence the distribution and ecology of infectious agents. The southern Beaufort Sea (SB) subpopulation of polar bears (Ursus maritimus) has experienced dramatic behavioral changes due to retreating sea ice and other climate-related factors, but the effects of these changes on physiology and infection remain poorly understood. Using serum from polar bears sampled between 2004 and 2015 and metagenomic DNA sequencing, we identified 48 viruses, all of the family Anelloviridae. Anelloviruses are small, ubiquitous infectious agents with circular single-stranded DNA genomes that are not known to cause disease but, in humans, covary in diversity and load with immunological compromise. We therefore examined the usefulness of anelloviruses as biomarkers of polar bear physiological stress related to climate and habitat use. Polar bear anelloviruses sorted into two distinct clades on a phylogenetic tree, both of which also contained anelloviruses of giant pandas (Ailuropoda melanoleuca), another ursid. Neither anellovirus diversity nor load were associated with any demographic variables, behavioral factors or direct physiological measures. However, pairwise genetic distances between anelloviruses were positively correlated with pairwise differences in sampling date, suggesting that the polar bear "anellome" is evolving over time. These findings suggest that anelloviruses are not a sensitive indicator of polar physiological stress, but they do provide a baseline for evaluating future changes to polar bear viromes.
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Affiliation(s)
- Tricia L Fry
- School of Veterinary Medicine, University of Wisconsin, Madison, WI, 53706
| | - Leah A Owens
- School of Veterinary Medicine, University of Wisconsin, Madison, WI, 53706
| | - Alison C Ketz
- Wisconsin Cooperative Research Unit, Department of Forest and Wildlife Ecology, University of Wisconsin, Madison, WI, 53706
| | - Todd C Atwood
- Alaska Science Center, U. S. Geological Survey, Anchorage, AK 99508
| | - Emily Dunay
- School of Veterinary Medicine, University of Wisconsin, Madison, WI, 53706
| | - Tony L Goldberg
- School of Veterinary Medicine, University of Wisconsin, Madison, WI, 53706
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5
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Brandhuber M, Atkinson S, Cunningham C, Roth T, Curry E. Assessing Dehydroepiandrosterone Sulfate (DHEAS) as a novel biomarker for monitoring estrus and successful reproduction in polar bears. Gen Comp Endocrinol 2023; 338:114276. [PMID: 36940836 PMCID: PMC10319433 DOI: 10.1016/j.ygcen.2023.114276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Revised: 03/13/2023] [Accepted: 03/17/2023] [Indexed: 03/23/2023]
Abstract
Polar bears (Ursus maritimus) in the wild are under threat due to climate change, primarily loss of sea ice, and experience poor reproductive success in zoos. The polar bear is a seasonally polyestrous species that exhibits embryonic diapause and pseudopregnancy, complicating characterization of reproductive function. Fecal excretion of testosterone and progesterone have been studied in polar bears, but accurately predicting reproductive success remains difficult. Dehydroepiandrosterone (DHEA) is a steroid hormone precursor correlated with reproductive success in other species, but has not been well studied in the polar bear. The purpose of the present study was to characterize the longitudinal excretion of DHEAS, the sulfated form of DHEA, from zoo-housed polar bears using a validated enzyme immunoassay. Lyophilized fecal samples from parturient females (n = 10), breeding non-parturient females (n = 11), a non-breeding adult female, a juvenile female, and a breeding adult male were investigated. Five of the breeding non-parturient females had been previously contracepted, while six were never contracepted. DHEAS concentrations were closely associated with testosterone concentrations (p < 0.05, rho > 0.57) for all reproductive statuses. Breeding females exhibited statistically significant (p < 0.05) increases in DHEAS concentration on or near breeding dates, which were not observed outside of the breeding season, or in the non-breeding or juvenile animals. Breeding non-parturient females exhibited higher median and baseline DHEAS concentrations than parturient females over the course of the breeding season. Previously contracepted (PC) breeding non-parturient females also exhibited higher season-long median and baseline DHEAS concentrations than non-previously (NPC) contracepted breeding non-parturient females. These findings suggest that DHEA is related to estrus or ovulation in the polar bear, that there is an optimal DHEA concentration window, and concentrations exceeding that threshold may be associated with reproductive dysfunction.
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Affiliation(s)
- Monica Brandhuber
- University of Alaska Fairbanks, College of Fisheries and Ocean Sciences, Fisheries Dept., Juneau Center, 17101 Pt. Lena Loop Road, Juneau, AK 99801, USA.
| | - Shannon Atkinson
- University of Alaska Fairbanks, College of Fisheries and Ocean Sciences, Fisheries Dept., Juneau Center, 17101 Pt. Lena Loop Road, Juneau, AK 99801, USA.
| | - Curry Cunningham
- University of Alaska Fairbanks, College of Fisheries and Ocean Sciences, Fisheries Dept., Juneau Center, 17101 Pt. Lena Loop Road, Juneau, AK 99801, USA.
| | - Terri Roth
- Center for Conservation and Research of Endangered Wildlife (CREW), Cincinnati Zoo and Botanical Garden, 3400 Vine Street, Cincinnati, OH 45220, USA.
| | - Erin Curry
- Center for Conservation and Research of Endangered Wildlife (CREW), Cincinnati Zoo and Botanical Garden, 3400 Vine Street, Cincinnati, OH 45220, USA.
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6
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Rode KD, Taras BD, Stricker CA, Atwood TC, Boucher NP, Durner GM, Derocher AE, Richardson ES, Cherry SG, Quakenbush L, Horstmann L, Bromaghin JF. Diet energy density estimated from isotopes in predator hair associated with survival, habitat, and population dynamics. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2023; 33:e2751. [PMID: 36151883 DOI: 10.1002/eap.2751] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 07/29/2022] [Accepted: 08/30/2022] [Indexed: 06/16/2023]
Abstract
Sea ice loss is fundamentally altering the Arctic marine environment. Yet there is a paucity of data on the adaptability of food webs to ecosystem change, including predator-prey interactions. Polar bears (Ursus maritimus) are an important subsistence resource for Indigenous people and an apex predator that relies entirely on the under-ice food web to meet its energy needs. In this study, we assessed whether polar bears maintained dietary energy density by prey switching in response to spatiotemporal variation in prey availability. We compared the macronutrient composition of diets inferred from stable carbon and nitrogen isotopes in polar bear guard hair (primarily representing summer/fall diet) during periods when bears had low and high survival (2004-2016), between bears that summered on land versus pack ice, and between bears occupying different regions of the Alaskan and Canadian Beaufort Sea. Polar bears consumed diets with lower energy density during periods of low survival, suggesting that concurrent increased dietary proportions of beluga whales (Delphinapterus leucas) did not offset reduced proportions of ringed seals (Pusa hispida). Diets with the lowest energy density and proportions from ringed seal blubber were consumed by bears in the western Beaufort Sea (Alaska) during a period when polar bear abundance declined. Intake required to meet energy requirements of an average free-ranging adult female polar bear was 2.1 kg/day on diets consumed during years with high survival but rose to 3.0 kg/day when survival was low. Although bears that summered onshore in the Alaskan Beaufort Sea had higher-fat diets than bears that summered on the pack ice, access to the remains of subsistence-harvested bowhead whales (Balaena mysticetus) contributed little to improving diet energy density. Because most bears in this region remain with the sea ice year round, prey switching and consumption of whale carcasses onshore appear insufficient to augment diets when availability of their primary prey, ringed seals, is reduced. Our results show that a strong predator-prey relationship between polar bears and ringed seals continues in the Beaufort Sea. The method of estimating dietary blubber using predator hair, demonstrated here, provides a new metric to monitor predator-prey relationships that affect individual health and population demographics.
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Affiliation(s)
- Karyn D Rode
- U.S. Geological Survey, Alaska Science Center, Anchorage, Alaska, USA
| | - Brian D Taras
- Alaska Department of Fish and Game, Fairbanks, Alaska, USA
| | - Craig A Stricker
- U.S. Geological Survey, Fort Collins Science Center, Fort Collins, Colorado, USA
| | - Todd C Atwood
- U.S. Geological Survey, Alaska Science Center, Anchorage, Alaska, USA
| | - Nicole P Boucher
- University of Alberta, Edmonton, Alberta, Canada
- School of Environmental Studies, University of Victoria, Victoria, British Columbia, Canada
| | - George M Durner
- U.S. Geological Survey, Alaska Science Center, Anchorage, Alaska, USA
| | | | - Evan S Richardson
- Environment and Climate Change Canada, Science and Technology Branch, Winnipeg, Manitoba, Canada
| | - Seth G Cherry
- University of Alberta, Edmonton, Alberta, Canada
- Parks Canada, East Kootenay, British Columbia, Canada
| | | | - Lara Horstmann
- College of Fisheries and Ocean Sciences, University of Alaska Fairbanks, Fairbanks, Alaska, USA
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7
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Kellner A, Atwood TC, Douglas DC, Breck SW, Wittemyer G. High winds and melting sea ice trigger landward movement in a polar bear population of concern. Ecosphere 2023. [DOI: 10.1002/ecs2.4420] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023] Open
Affiliation(s)
- Annie Kellner
- Graduate Degree Program in Ecology Colorado State University Fort Collins Colorado USA
- Department of Fish, Wildlife, and Conservation Biology Colorado State University Fort Collins Colorado USA
| | - Todd C. Atwood
- U.S. Geological Survey Alaska Science Center Anchorage Alaska USA
| | | | - Stewart W. Breck
- USDA‐WS‐National Wildlife Research Center Fort Collins Colorado USA
| | - George Wittemyer
- Graduate Degree Program in Ecology Colorado State University Fort Collins Colorado USA
- Department of Fish, Wildlife, and Conservation Biology Colorado State University Fort Collins Colorado USA
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8
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Rode KD, Douglas D, Atwood T, Durner G, Wilson R, Pagano A. Observed and forecasted changes in land use by polar bears in the Beaufort and Chukchi Seas, 1985–2040. Glob Ecol Conserv 2022. [DOI: 10.1016/j.gecco.2022.e02319] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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9
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Babiy UV, Salomashkina VV, Kulemeev PS, Kholodova MV, Gruzdev AR, Regehr EV. First evidence of a brown bear on Wrangel Island, Russia. URSUS 2022. [DOI: 10.2192/ursus-d-20-00024.1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Affiliation(s)
| | | | | | | | | | - Eric V. Regehr
- Polar Science Center, University of Washington, Seattle, Washington, USA
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10
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Regehr EV, Runge MC, Von Duyke A, Wilson RR, Polasek L, Rode KD, Hostetter NJ, Converse SJ. Demographic risk assessment for a harvested species threatened by climate change: polar bears in the Chukchi Sea. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2021; 31:e02461. [PMID: 34582601 PMCID: PMC9286533 DOI: 10.1002/eap.2461] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 02/09/2021] [Accepted: 04/05/2021] [Indexed: 06/13/2023]
Abstract
Climate change threatens global biodiversity. Many species vulnerable to climate change are important to humans for nutritional, cultural, and economic reasons. Polar bears Ursus maritimus are threatened by sea-ice loss and represent a subsistence resource for Indigenous people. We applied a novel population modeling-management framework that is based on species life history and accounts for habitat loss to evaluate subsistence harvest for the Chukchi Sea (CS) polar bear subpopulation. Harvest strategies followed a state-dependent approach under which new data were used to update the harvest on a predetermined management interval. We found that a harvest strategy with a starting total harvest rate of 2.7% (˜85 bears/yr at current abundance), a 2:1 male-to-female ratio, and a 10-yr management interval would likely maintain subpopulation abundance above maximum net productivity level for the next 35 yr (approximately three polar bear generations), our primary criterion for sustainability. Plausible bounds on starting total harvest rate were 1.7-3.9%, where the range reflects uncertainty due to sampling variation, environmental variation, model selection, and differing levels of risk tolerance. The risk of undesired demographic outcomes (e.g., overharvest) was positively related to harvest rate, management interval, and projected declines in environmental carrying capacity; and negatively related to precision in population data. Results reflect several lines of evidence that the CS subpopulation has been productive in recent years, although it is uncertain how long this will last as sea-ice loss continues. Our methods provide a template for balancing trade-offs among protection, use, research investment, and other factors. Demographic risk assessment and state-dependent management will become increasingly important for harvested species, like polar bears, that exhibit spatiotemporal variation in their response to climate change.
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Affiliation(s)
- Eric V. Regehr
- Polar Science CenterApplied Physics LaboratoryUniversity of WashingtonSeattleWashington98105USA
| | - Michael C. Runge
- Patuxent Wildlife Research CenterU.S. Geological SurveyLaurelMaryland20708USA
| | - Andrew Von Duyke
- Department of Wildlife ManagementNorth Slope BoroughUtqiaġvikAlaska99723USA
| | - Ryan R. Wilson
- Marine Mammals ManagementU.S. Fish and Wildlife ServiceAnchorageAlaska99503USA
| | - Lori Polasek
- Division of Wildlife ConservationAlaska Department of Fish and GameJuneauAlaska99802USA
| | - Karyn D. Rode
- Alaska Science CenterU.S. Geological SurveyAnchorageAlaska99508USA
| | - Nathan J. Hostetter
- Washington Cooperative Fish and Wildlife Research UnitSchool of Aquatic and Fishery SciencesUniversity of WashingtonSeattleWashington98105USA
| | - Sarah J. Converse
- Washington Cooperative Fish and Wildlife Research UnitSchool of Environmental and Forest Sciences (SEFS) & School of Aquatic and Fishery Sciences (SAFS)U.S. Geological SurveyUniversity of WashingtonSeattleWashington98105USA
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11
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Pilfold NW, Richardson ES, Ellis J, Jenkins E, Scandrett WB, Hernández‐Ortiz A, Buhler K, McGeachy D, Al‐Adhami B, Konecsni K, Lobanov VA, Owen MA, Rideout B, Lunn NJ. Long-term increases in pathogen seroprevalence in polar bears (Ursus maritimus) influenced by climate change. GLOBAL CHANGE BIOLOGY 2021; 27:4481-4497. [PMID: 34292654 PMCID: PMC8457125 DOI: 10.1111/gcb.15537] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Accepted: 12/28/2020] [Indexed: 05/10/2023]
Abstract
The influence of climate change on wildlife disease dynamics is a burgeoning conservation and human health issue, but few long-term studies empirically link climate to pathogen prevalence. Polar bears (Ursus maritimus) are vulnerable to the negative impacts of sea ice loss as a result of accelerated Arctic warming. While studies have associated changes in polar bear body condition, reproductive output, survival, and abundance to reductions in sea ice, no long-term studies have documented the impact of climate change on pathogen exposure. We examined 425 serum samples from 381 adult polar bears, collected in western Hudson Bay (WH), Canada, for antibodies to selected pathogens across three time periods: 1986-1989 (n = 157), 1995-1998 (n = 159) and 2015-2017 (n = 109). We ran serological assays for antibodies to seven pathogens: Toxoplasma gondii, Neospora caninum, Trichinella spp., Francisella tularensis, Bordetella bronchiseptica, canine morbillivirus (CDV) and canine parvovirus (CPV). Seroprevalence of zoonotic parasites (T. gondii, Trichinella spp.) and bacterial pathogens (F. tularensis, B. bronchiseptica) increased significantly between 1986-1989 and 1995-1998, ranging from +6.2% to +20.8%, with T. gondii continuing to increase into 2015-2017 (+25.8% overall). Seroprevalence of viral pathogens (CDV, CPV) and N. caninum did not change with time. Toxoplasma gondii seroprevalence was higher following wetter summers, while seroprevalences of Trichinella spp. and B. bronchiseptica were positively correlated with hotter summers. Seroprevalence of antibodies to F. tularensis increased following years polar bears spent more days on land, and polar bears previously captured in human settlements were more likely to be seropositive for Trichinella spp. As the Arctic has warmed due to climate change, zoonotic pathogen exposure in WH polar bears has increased, driven by numerous altered ecosystem pathways.
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Affiliation(s)
- Nicholas W. Pilfold
- Conservation Science and Wildlife HealthSan Diego Zoo Wildlife AllianceEscondidoCAUSA
| | - Evan S. Richardson
- Wildlife Research Division, Science and Technology BranchEnvironment and Climate Change CanadaWinnipegMBCanada
| | - John Ellis
- Department of Veterinary MicrobiologyUniversity of SaskatchewanSaskatoonSKCanada
| | - Emily Jenkins
- Department of Veterinary MicrobiologyUniversity of SaskatchewanSaskatoonSKCanada
| | - W. Brad Scandrett
- Centre for Food‐borne and Animal ParasitologyCanadian Food Inspection AgencySaskatoonSKCanada
| | | | - Kayla Buhler
- Department of Veterinary MicrobiologyUniversity of SaskatchewanSaskatoonSKCanada
| | - David McGeachy
- Wildlife Research Division, Science and Technology BranchEnvironment and Climate Change CanadaEdmontonABCanada
| | - Batol Al‐Adhami
- Centre for Food‐borne and Animal ParasitologyCanadian Food Inspection AgencySaskatoonSKCanada
| | - Kelly Konecsni
- Centre for Food‐borne and Animal ParasitologyCanadian Food Inspection AgencySaskatoonSKCanada
| | - Vladislav A. Lobanov
- Centre for Food‐borne and Animal ParasitologyCanadian Food Inspection AgencySaskatoonSKCanada
| | - Megan A. Owen
- Conservation Science and Wildlife HealthSan Diego Zoo Wildlife AllianceEscondidoCAUSA
| | - Bruce Rideout
- Conservation Science and Wildlife HealthSan Diego Zoo Wildlife AllianceEscondidoCAUSA
| | - Nicholas J. Lunn
- Wildlife Research Division, Science and Technology BranchEnvironment and Climate Change CanadaEdmontonABCanada
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12
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Bromaghin JF, Douglas DC, Durner GM, Simac KS, Atwood TC. Survival and abundance of polar bears in Alaska's Beaufort Sea, 2001-2016. Ecol Evol 2021; 11:14250-14267. [PMID: 34707852 PMCID: PMC8525099 DOI: 10.1002/ece3.8139] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 08/02/2021] [Accepted: 09/06/2021] [Indexed: 12/20/2022] Open
Abstract
The Arctic Ocean is undergoing rapid transformation toward a seasonally ice-free ecosystem. As ice-adapted apex predators, polar bears (Ursus maritimus) are challenged to cope with ongoing habitat degradation and changes in their prey base driven by food-web response to climate warming. Knowledge of polar bear response to environmental change is necessary to understand ecosystem dynamics and inform conservation decisions. In the southern Beaufort Sea (SBS) of Alaska and western Canada, sea ice extent has declined since satellite observations began in 1979 and available evidence suggests that the carrying capacity of the SBS for polar bears has trended lower for nearly two decades. In this study, we investigated the population dynamics of polar bears in Alaska's SBS from 2001 to 2016 using a multistate Cormack-Jolly-Seber mark-recapture model. States were defined as geographic regions, and we used location data from mark-recapture observations and satellite-telemetered bears to model transitions between states and thereby explain heterogeneity in recapture probabilities. Our results corroborate prior findings that the SBS subpopulation experienced low survival from 2003 to 2006. Survival improved modestly from 2006 to 2008 and afterward rebounded to comparatively high levels for the remainder of the study, except in 2012. Abundance moved in concert with survival throughout the study period, declining substantially from 2003 and 2006 and afterward fluctuating with lower variation around an average of 565 bears (95% Bayesian credible interval [340, 920]) through 2015. Even though abundance was comparatively stable and without sustained trend from 2006 to 2015, polar bears in the Alaska SBS were less abundant over that period than at any time since passage of the U.S. Marine Mammal Protection Act. The potential for recovery is likely limited by the degree of habitat degradation the subpopulation has experienced, and future reductions in carrying capacity are expected given current projections for continued climate warming.
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Affiliation(s)
| | | | | | | | - Todd C. Atwood
- U.S. Geological SurveyAlaska Science CenterAnchorageAKUSA
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13
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Van der Walt M, Neuman-Lee LA, Terletzky PA, Atwood TC, Gese EM, French SS. Measuring adrenal and reproductive hormones in hair from Southern Beaufort Sea polar bears (Ursus maritimus). Gen Comp Endocrinol 2021; 310:113807. [PMID: 33964286 DOI: 10.1016/j.ygcen.2021.113807] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Revised: 04/29/2021] [Accepted: 05/03/2021] [Indexed: 11/23/2022]
Abstract
Polar bears (Ursus maritimus) use sea ice to access marine mammal prey. In Alaska's Southern Beaufort Sea, the declining availability of sea ice habitat in summer and fall has reduced opportunities for polar bears to routinely hunt on the ice for seals, their primary prey. This reduced access to prey may result in physiological stress with subsequent potential consequences to reproductive function (physiological changes that accompany reproduction), which can be measured via reproductive hormones. Hormone concentrations in hair can be used as a minimally invasive alternative to serum concentrations, which must come from animal captures. Hair samples also provide a long-term average measurement of hormone concentrations that is not influenced by short-term fluctuations like that of serum. The aim of this study was (1) to determine if a radioimmunoassay could be used to measure adrenal and reproductive hormones in polar bear hair, and (2) to determine what the relationship is between these hormones and other reproductive, condition, and demographic parameters of polar bears. We successfully validated this method for cortisol, progesterone, estradiol, and testosterone through the analysis of hair and serum of 141 free-ranging polar bears. We found that while hair cannot be used to estimate serum hormone concentrations during the breeding season, hormone concentrations in hair can be used to measure reproductive function in polar bears. Further, our findings support trends in previous studies measuring hormone concentrations in serum. We found that adrenal and some reproductive hormones were positively correlated in hair samples of females. Associations between hormone concentrations in hair and serum did not vary relative to reproductive status of adult females. Serum testosterone increased throughout the breeding season for adult males and was significantly associated with body mass index (BMI). Our research supports the use of hair as a measure of reproductive function in polar bears and allows us to monitor the future effects of climate change on polar bear physiology.
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Affiliation(s)
- Marilize Van der Walt
- Department of Biology and the Ecology Center, Utah State University, 5305 Old Main Hill, Logan, UT 84322, USA.
| | - Lorin A Neuman-Lee
- Department of Biology and the Ecology Center, Utah State University, 5305 Old Main Hill, Logan, UT 84322, USA.
| | - Patricia A Terletzky
- Department of Wildland Resources, Utah State University, 5230 Old Main Hill, Logan, UT 84322, USA.
| | - Todd C Atwood
- U.S. Geological Survey, Alaska Science Center, 4210 University Drive, Anchorage, AK 99508, USA.
| | - Eric M Gese
- U.S. Department of Agriculture, Wildlife Services, National Wildlife Research Center, Department of Wildland Resources, Utah State University, Logan, UT 84322, USA.
| | - Susannah S French
- Department of Biology and the Ecology Center, Utah State University, 5305 Old Main Hill, Logan, UT 84322, USA
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14
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Age-structured Jolly-Seber model expands inference and improves parameter estimation from capture-recapture data. PLoS One 2021; 16:e0252748. [PMID: 34106979 PMCID: PMC8189494 DOI: 10.1371/journal.pone.0252748] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Accepted: 05/22/2021] [Indexed: 11/19/2022] Open
Abstract
Understanding the influence of individual attributes on demographic processes is a key objective of wildlife population studies. Capture-recapture and age data are commonly collected to investigate hypotheses about survival, reproduction, and viability. We present a novel age-structured Jolly-Seber model that incorporates age and capture-recapture data to provide comprehensive information on population dynamics, including abundance, age-dependent survival, recruitment, age structure, and population growth rates. We applied our model to a multi-year capture-recapture study of polar bears (Ursus maritimus) in western Hudson Bay, Canada (2012–2018), where management and conservation require a detailed understanding of how polar bears respond to climate change and other factors. In simulation studies, the age-structured Jolly-Seber model improved precision of survival, recruitment, and annual abundance estimates relative to standard Jolly-Seber models that omit age information. Furthermore, incorporating age information improved precision of population growth rates, increased power to detect trends in abundance, and allowed direct estimation of age-dependent survival and changes in annual age structure. Our case study provided detailed evidence for senescence in polar bear survival. Median survival estimates were lower (<0.95) for individuals aged <5 years, remained high (>0.95) for individuals aged 7–22 years, and subsequently declined to near zero for individuals >30 years. We also detected cascading effects of large recruitment classes on population age structure, which created major shifts in age structure when these classes entered the population and then again when they reached prime breeding ages (10–15 years old). Overall, age-structured Jolly-Seber models provide a flexible means to investigate ecological and evolutionary processes that shape populations (e.g., via senescence, life expectancy, and lifetime reproductive success) while improving our ability to investigate population dynamics and forecast population changes from capture-recapture data.
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15
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Conn PB, Chernook VI, Moreland EE, Trukhanova IS, Regehr EV, Vasiliev AN, Wilson RR, Belikov SE, Boveng PL. Aerial survey estimates of polar bears and their tracks in the Chukchi Sea. PLoS One 2021; 16:e0251130. [PMID: 33956835 PMCID: PMC8101751 DOI: 10.1371/journal.pone.0251130] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Accepted: 04/20/2021] [Indexed: 11/19/2022] Open
Abstract
Polar bears are of international conservation concern due to climate change but are difficult to study because of low densities and an expansive, circumpolar distribution. In a collaborative U.S.-Russian effort in spring of 2016, we used aerial surveys to detect and estimate the abundance of polar bears on sea ice in the Chukchi Sea. Our surveys used a combination of thermal imagery, digital photography, and human observations. Using spatio-temporal statistical models that related bear and track densities to physiographic and biological covariates (e.g., sea ice extent, resource selection functions derived from satellite tags), we predicted abundance and spatial distribution throughout our study area. Estimates of 2016 abundance ([Formula: see text]) ranged from 3,435 (95% CI: 2,300-5,131) to 5,444 (95% CI: 3,636-8,152) depending on the proportion of bears assumed to be missed on the transect line during Russian surveys (g(0)). Our point estimates are larger than, but of similar magnitude to, a recent estimate for the period 2008-2016 ([Formula: see text]; 95% CI 1,522-5,944) derived from an integrated population model applied to a slightly smaller area. Although a number of factors (e.g., equipment issues, differing platforms, low sample sizes, size of the study area relative to sampling effort) required us to make a number of assumptions to generate estimates, it establishes a useful lower bound for abundance, and suggests high spring polar bear densities on sea ice in Russian waters south of Wrangell Island. With future improvements, we suggest that springtime aerial surveys may represent a plausible avenue for studying abundance and distribution of polar bears and their prey over large, remote areas.
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Affiliation(s)
- Paul B. Conn
- Alaska Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, Seattle, Washington, United States of America
- * E-mail:
| | - Vladimir I. Chernook
- Ecological Center, Autonomous Non-Commercial Organization, Saint-Petersburg, Russia
| | - Erin E. Moreland
- Alaska Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, Seattle, Washington, United States of America
| | - Irina S. Trukhanova
- North Pacific Wildlife Consulting, LLC, Seattle, Washington, United States of America
| | - Eric V. Regehr
- Marine Mammals Management, United States Fish and Wildlife Service, Anchorage, Alaska, United States of America
- Applied Physics Laboratory, Polar Science Center, University of Washington, Seattle, Washington, United States of America
| | | | - Ryan R. Wilson
- Marine Mammals Management, United States Fish and Wildlife Service, Anchorage, Alaska, United States of America
| | - Stanislav E. Belikov
- All-Russian Research Institute for Nature Protection (Federal State Budgetary Institution), Moscow, Russia
| | - Peter L. Boveng
- Alaska Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, Seattle, Washington, United States of America
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16
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Heemskerk S, Johnson AC, Hedman D, Trim V, Lunn NJ, McGeachy D, Derocher AE. Temporal dynamics of human-polar bear conflicts in Churchill, Manitoba. Glob Ecol Conserv 2020. [DOI: 10.1016/j.gecco.2020.e01320] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
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17
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Quantifying tourism booms and the increasing footprint in the Arctic with social media data. PLoS One 2020; 15:e0227189. [PMID: 31945097 PMCID: PMC6964912 DOI: 10.1371/journal.pone.0227189] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Accepted: 12/09/2019] [Indexed: 11/28/2022] Open
Abstract
Arctic tourism has rapidly increased in the past two decades. We used social media data to examine localized tourism booms and quantify the spatial expansion of the Arctic tourism footprint. We extracted geotagged locations from over 800,000 photos on Flickr and mapped these across space and time. We critically examine the use of social media as a data source in data-poor regions, and find that while social media data is not suitable as an early warning system of tourism growth in less visited parts of the world, it can be used to map changes at large spatial scales. Our results show that the footprint of summer tourism quadrupled and winter tourism increased by over 600% between 2006 and 2016, although large areas of the Arctic remain untouched by tourism. This rapid increase in the tourism footprint raises concerns about the impacts and sustainability of tourism on Arctic ecosystems and communities. This boom is set to continue, as new parts of the Arctic are being opened to tourism by melting sea ice, new airports and continued promotion of the Arctic as a ‘last chance to see’ destination. Arctic societies face complex decisions about whether this ongoing growth is socially and environmentally sustainable.
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18
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Wilson RR, Durner GM. Seismic Survey Design and Effects on Maternal Polar Bear Dens. J Wildl Manage 2019. [DOI: 10.1002/jwmg.21800] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Ryan R. Wilson
- U.S. Fish and Wildlife Service 1011 E. Tudor Rd. Anchorage AK 99503 USA
| | - George M. Durner
- U.S. Geological Survey, Alaska Science Center 4210 University Dr. Anchorage AK 99508 USA
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19
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Post E, Alley RB, Christensen TR, Macias-Fauria M, Forbes BC, Gooseff MN, Iler A, Kerby JT, Laidre KL, Mann ME, Olofsson J, Stroeve JC, Ulmer F, Virginia RA, Wang M. The polar regions in a 2°C warmer world. SCIENCE ADVANCES 2019; 5:eaaw9883. [PMID: 31840060 PMCID: PMC6892626 DOI: 10.1126/sciadv.aaw9883] [Citation(s) in RCA: 132] [Impact Index Per Article: 26.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Accepted: 09/26/2019] [Indexed: 05/21/2023]
Abstract
Over the past decade, the Arctic has warmed by 0.75°C, far outpacing the global average, while Antarctic temperatures have remained comparatively stable. As Earth approaches 2°C warming, the Arctic and Antarctic may reach 4°C and 2°C mean annual warming, and 7°C and 3°C winter warming, respectively. Expected consequences of increased Arctic warming include ongoing loss of land and sea ice, threats to wildlife and traditional human livelihoods, increased methane emissions, and extreme weather at lower latitudes. With low biodiversity, Antarctic ecosystems may be vulnerable to state shifts and species invasions. Land ice loss in both regions will contribute substantially to global sea level rise, with up to 3 m rise possible if certain thresholds are crossed. Mitigation efforts can slow or reduce warming, but without them northern high latitude warming may accelerate in the next two to four decades. International cooperation will be crucial to foreseeing and adapting to expected changes.
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Affiliation(s)
- Eric Post
- Department of Wildlife, Fish, and Conservation Biology, University of California, Davis, Davis, CA 95616, USA
| | - Richard B. Alley
- Department of Geosciences, and Earth and Environmental Systems Institute, The Pennsylvania State University, University Park, PA 16802, USA
| | - Torben R. Christensen
- Department of Bioscience, Arctic Research Centre, Aarhus University, Frederiksborgvej 399, 4000 Roskilde, Denmark
| | - Marc Macias-Fauria
- School of Geography and the Environment, University of Oxford, Oxford OX1 3QY, UK
| | - Bruce C. Forbes
- Arctic Centre, University of Lapland, Box 122, FI-96101 Rovaniemi, Finland
| | - Michael N. Gooseff
- Institute of Arctic and Alpine Research, University of Colorado, Boulder, CO 80303, USA
| | - Amy Iler
- Chicago Botanic Garden, 1000 Lake Cook Road, Glencoe, IL 60022, USA
| | - Jeffrey T. Kerby
- Department of Wildlife, Fish, and Conservation Biology, University of California, Davis, Davis, CA 95616, USA
- Neukom Institute for Computational Science, Institute of Arctic Studies, and Environmental Studies Program, Dartmouth College, Hanover, NH 03755, USA
| | - Kristin L. Laidre
- Polar Science Center, Applied Physics Laboratory, University of Washington, 1013 NE 40th Street, Seattle, WA 98105, USA
| | - Michael E. Mann
- Department of Meteorology and Atmospheric Science and Department of Geosciences, The Pennsylvania State University, University Park, PA 16802, USA
| | - Johan Olofsson
- Department of Ecology and Environmental Science, Umeå University, S-901 87 Umeå, Sweden
| | - Julienne C. Stroeve
- University College London, Bloomsbury, London, UK
- National Snow and Ice Data Center, Boulder, CO 80303, USA
| | - Fran Ulmer
- Chair, U.S. Arctic Research Commission, 420 L Street, Suite 315 Anchorage, AK 99501, USA
- Chair, U.S. Artic Research Commission, 4350 N. Fairfax Drive, Suite 510, Arlington, VA 22203, USA
- Belfer Center for Science and International Affairs John F. Kennedy School of Government, Harvard University, Cambridge, MA 02138, USA
| | - Ross A. Virginia
- Institute of Arctic Studies, and Environmental Studies Program, Dartmouth College, Hanover, NH 03755, USA
| | - Muyin Wang
- Joint Institute for the Study of the Atmosphere and Ocean, University of Washington, Seattle, WA 98195, USA
- National Oceanic and Atmospheric Administration Pacific Marine Environmental Laboratory, Seattle, WA 98115, USA
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20
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Durner GM, Douglas DC, Atwood TC. Are polar bear habitat resource selection functions developed from 1985-1995 data still useful? Ecol Evol 2019; 9:8625-8638. [PMID: 31410267 PMCID: PMC6686286 DOI: 10.1002/ece3.5401] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Revised: 05/20/2019] [Accepted: 05/28/2019] [Indexed: 02/04/2023] Open
Abstract
Greenhouse-gas-induced warming in the Arctic has caused declines in sea ice extent and changed its composition, raising concerns by all circumpolar nations for polar bear conservation.Negative impacts have been observed in three well-studied polar bear subpopulations. Most subpopulations, however, receive little or no direct monitoring, hence, resource selection functions (RSF) may provide a useful proxy of polar bear distributions. However, the efficacy of RSFs constructed from past data, that is, reference RSFs, may be degraded under contemporary conditions, especially in a rapidly changing environment.We assessed published Arctic-wide reference RSFs using tracking data from adult female polar bears captured in the Beaufort Sea. We compared telemetry-derived seasonal distributions of polar bears to RSF-defined optimal sea ice habitat during the period of RSF model development, 1985-1995, and two subsequent periods with diminished sea ice: 1996-2006 and 2007-2016. From these comparisons, we assessed the applicability of the reference RSFs for contemporary polar bear conservation.In the two decades following the 1985-1995 reference period, use and availability of optimal habitat by polar bears declined during the ice melt, ice minimum, and ice growth seasons. During the ice maximum season (i.e., winter), polar bears used the best habitat available, which changed relatively little across the three decades of study. During the ice melt, ice minimum, and ice growth seasons, optimal habitat in areas used by polar bears decreased and was displaced north and east of the Alaska Beaufort Sea coast. As optimal habitat diminished in these seasons, polar bears expanded their range and occupied greater areas of suboptimal habitat.Synthesis and applications: Sea ice declines due to climate change continue to challenge polar bears and their conservation. The distribution of Southern Beaufort Sea polar bears remained similar during the ice maximum season, so the reference RSFs developed from data collected >20 years ago continue to accurately model their winter distribution. In contrast, reference RSFs for the ice transitional and minimum seasons showed diminished predictive efficacy but were useful in revealing that contemporary polar bears have been increasingly forced to use suboptimal habitats during those seasons.
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Affiliation(s)
| | | | - Todd C. Atwood
- Alaska Science CenterU.S. Geological SurveyAnchorageAlaskaUSA
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21
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Behaviour and characteristics of mating polar bears (Ursus maritimus) in the Beaufort Sea, Canada. Polar Biol 2019. [DOI: 10.1007/s00300-019-02485-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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22
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Whiteman JP, Harlow HJ, Durner GM, Regehr EV, Amstrup SC, Ben-David M. Heightened Immune System Function in Polar Bears Using Terrestrial Habitats. Physiol Biochem Zool 2019; 92:1-11. [DOI: 10.1086/698996] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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23
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Regehr EV, Hostetter NJ, Wilson RR, Rode KD, Martin MS, Converse SJ. Integrated Population Modeling Provides the First Empirical Estimates of Vital Rates and Abundance for Polar Bears in the Chukchi Sea. Sci Rep 2018; 8:16780. [PMID: 30429493 PMCID: PMC6235872 DOI: 10.1038/s41598-018-34824-7] [Citation(s) in RCA: 69] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Accepted: 10/22/2018] [Indexed: 12/27/2022] Open
Abstract
Large carnivores are imperiled globally, and characteristics making them vulnerable to extinction (e.g., low densities and expansive ranges) also make it difficult to estimate demographic parameters needed for management. Here we develop an integrated population model to analyze capture-recapture, radiotelemetry, and count data for the Chukchi Sea subpopulation of polar bears (Ursus maritimus), 2008-2016. Our model addressed several challenges in capture-recapture studies for polar bears by including a multievent structure reflecting location and life history states, while accommodating state uncertainty. Female breeding probability was 0.83 (95% credible interval [CRI] = 0.71-0.90), with litter sizes of 2.18 (95% CRI = 1.71-2.82) for age-zero and 1.61 (95% CRI = 1.46-1.80) for age-one cubs. Total adult survival was 0.90 (95% CRI = 0.86-0.92) for females and 0.89 (95% CRI = 0.83-0.93) for males. Spring on-ice densities west of Alaska were 0.0030 bears/km2 (95% CRI = 0.0016-0.0060), similar to 1980s-era density estimates although methodological differences complicate comparison. Abundance of the Chukchi Sea subpopulation, derived by extrapolating density from the study area using a spatially-explicit habitat metric, was 2,937 bears (95% CRI = 1,552-5,944). Our findings are consistent with other lines of evidence suggesting the Chukchi Sea subpopulation has been productive in recent years, although it is uncertain how long this will continue given sea-ice loss due to climate change.
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Affiliation(s)
- Eric V Regehr
- Marine Mammals Management, U.S. Fish and Wildlife Service, Anchorage, AK, USA.
- Polar Science Center, University of Washington, Seattle, WA, USA.
| | - Nathan J Hostetter
- U.S. Geological Survey, Patuxent Wildlife Research Center, Laurel, MD, USA
| | - Ryan R Wilson
- Marine Mammals Management, U.S. Fish and Wildlife Service, Anchorage, AK, USA
| | - Karyn D Rode
- U.S. Geological Survey, Alaska Science Center, Anchorage, AK, USA
| | - Michelle St Martin
- Marine Mammals Management, U.S. Fish and Wildlife Service, Anchorage, AK, USA
| | - Sarah J Converse
- U.S. Geological Survey, Washington Cooperative Fish and Wildlife Research Unit, School of Environmental and Forest Sciences (SEFS) & School of Aquatic and Fishery Sciences (SAFS), University of Washington, Seattle, WA, USA
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24
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Hamilton SG, Derocher AE. Assessment of global polar bear abundance and vulnerability. Anim Conserv 2018. [DOI: 10.1111/acv.12439] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- S. G. Hamilton
- Department of Biological Sciences University of Alberta Edmonton AB Canada
| | - A. E. Derocher
- Department of Biological Sciences University of Alberta Edmonton AB Canada
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25
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Harvey JA, van den Berg D, Ellers J, Kampen R, Crowther TW, Roessingh P, Verheggen B, Nuijten RJM, Post E, Lewandowsky S, Stirling I, Balgopal M, Amstrup SC, Mann ME. Internet Blogs, Polar Bears, and Climate-Change Denial by Proxy. Bioscience 2018; 68:281-287. [PMID: 29662248 PMCID: PMC5894087 DOI: 10.1093/biosci/bix133] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Increasing surface temperatures, Arctic sea-ice loss, and other evidence of anthropogenic global warming (AGW) are acknowledged by every major scientific organization in the world. However, there is a wide gap between this broad scientific consensus and public opinion. Internet blogs have strongly contributed to this consensus gap by fomenting misunderstandings of AGW causes and consequences. Polar bears (Ursus maritimus) have become a "poster species" for AGW, making them a target of those denying AGW evidence. Here, focusing on Arctic sea ice and polar bears, we show that blogs that deny or downplay AGW disregard the overwhelming scientific evidence of Arctic sea-ice loss and polar bear vulnerability. By denying the impacts of AGW on polar bears, bloggers aim to cast doubt on other established ecological consequences of AGW, aggravating the consensus gap. To counter misinformation and reduce this gap, scientists should directly engage the public in the media and blogosphere.
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Affiliation(s)
- Jeffrey A Harvey
- Department of Terrestrial Ecology at the Netherlands Institute of Ecology, in Wageningen. JAH
| | - Daphne van den Berg
- Department of Ecological Sciences–Animal Ecology at the VU University Amsterdam, in The Netherlands
| | - Jacintha Ellers
- Department of Ecological Sciences–Animal Ecology at the VU University Amsterdam, in The Netherlands
| | | | - Thomas W Crowther
- Department of Terrestrial Ecology at the Netherlands Institute of Ecology, in Wageningen, and with the Institute of Integrative Biology, in Zürich, Switzerland
| | - Peter Roessingh
- Institute for Biodiversity and Ecosystem Dynamics at the University of Amsterdam, in The Netherlands
| | | | - Rascha J M Nuijten
- Department of Animal Ecology at Netherlands Institute of Ecology, in Wageningen
| | - Eric Post
- Department of Wildlife, Fish, and Conservation Biology at the University of California, Davis
| | - Stephan Lewandowsky
- School of Experimental Psychology and Cabot Institute at the University of Bristol, in the United Kingdom, and with CSIRO Oceans and Atmosphere, in Hobart, Tasmania, Australia
| | - Ian Stirling
- Wildlife Research Division of Environment and Climate Change Canada, and with the Department of Biological Sciences at the University of Alberta, in Edmonton, Canada
| | - Meena Balgopal
- Department of Biology at Colorado State University, in Fort Collins
| | - Steven C Amstrup
- Polar Bears International, in Bozeman, Montana, and with the Department of Zoology and Physiology at the University of Wyoming, in Laramie
| | - Michael E Mann
- Department of Meteorology and Atmospheric Science at Pennsylvania State University, in University Park
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26
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Brown TM, Macdonald RW, Muir DCG, Letcher RJ. The distribution and trends of persistent organic pollutants and mercury in marine mammals from Canada's Eastern Arctic. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 618:500-517. [PMID: 29145101 DOI: 10.1016/j.scitotenv.2017.11.052] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Revised: 11/03/2017] [Accepted: 11/04/2017] [Indexed: 05/15/2023]
Abstract
Arctic contaminant research in the marine environment has focused on organohalogen compounds and mercury mainly because they are bioaccumulative, persistent and toxic. This review summarizes and discusses the patterns and trends of persistent organic pollutants (POPs) and mercury in ringed seals (Pusa hispida) and polar bears (Ursus maritimus) in the Eastern Canadian Arctic relative to the rest of the Canadian Arctic. The review provides explanations for these trends and looks at the implications of climate-related changes on contaminants in these marine mammals in a region that has been reviewed little. Presently, the highest levels of total mercury (THg) and the legacy pesticide HCH in ringed seals and polar bears are found in the Western Canadian Arctic relative to other locations. Whereas, highest levels of some legacy contaminants, including ∑PCBs, PCB 153, ∑DDTs, p,p'-DDE, ∑CHLs, ClBz are found in the east (i.e., Ungava Bay and Labrador) and in the Beaufort Sea relative to other locations. The highest levels of recent contaminants, including PBDEs and PFOS are found at lower latitudes. Feeding ecology (e.g., feeding at a higher trophic position) is shaping the elevated levels of THg and some legacy contaminants in the west compared to the east. Spatial and temporal trends for POPs and THg are underpinned by historical loadings of surface ocean reservoirs including the Western Arctic Ocean and the North Atlantic Ocean. Trends set up by the distribution of water masses across the Canadian Arctic Archipelago are then acted upon locally by on-going atmospheric deposition, which is the dominant contributor for more recent contaminants. Warming and continued decline in sea ice are likely to result in further shifts in food web structure, which are likely to increase contaminant burdens in marine mammals. Monitoring of seawater and a range of trophic levels would provide a better basis to inform communities about contaminants in traditionally harvested foods, allow us to understand the causes of contaminant trends in marine ecosystems, and to track environmental response to source controls instituted under international conventions.
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Affiliation(s)
- Tanya M Brown
- Memorial University of Newfoundland, St. John's, Newfoundland A1B 3X9, Canada.
| | - Robie W Macdonald
- Fisheries, Oceans and the Canadian Coast Guard, Institute of Ocean Sciences, Sidney, British Columbia V8L 4B2, Canada; Centre for Earth Observation Science, Department of Environment and Geography, University of Manitoba, Winnipeg R3T 2N2, Canada
| | - Derek C G Muir
- Environment Canada, Canada Centre for Inland Waters, 867 Lakeshore Road, Burlington, Ontario L7R 4A6, Canada
| | - Robert J Letcher
- Environment and Climate Change Canada, National Wildlife Research Centre, Carleton University, Raven Road, Ottawa, Ontario K1A 0H3, Canada
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27
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Neuman‐Lee LA, Terletzky PA, Atwood TC, Gese EM, Smith GD, Greenfield S, Pettit J, French SS. Demographic and temporal variations in immunity and condition of polar bears (
Ursus maritimus
) from the southern Beaufort Sea. JOURNAL OF EXPERIMENTAL ZOOLOGY PART 2017; 327:333-346. [DOI: 10.1002/jez.2112] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Revised: 08/27/2017] [Accepted: 08/29/2017] [Indexed: 11/09/2022]
Affiliation(s)
| | | | - Todd C. Atwood
- U.S. Geological Survey Alaska Science Center Anchorage Alaska
| | - Eric M. Gese
- Department of Wildland Resources Utah State University Logan Utah
- U.S. Department of Agriculture Wildlife Services National Wildlife Research Center Logan Utah
| | - Geoffrey D. Smith
- Department of Biological Sciences Dixie State University St. George Utah
| | | | - John Pettit
- Department of Biology Utah State University Logan Utah
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Durner GM, Douglas DC, Albeke SE, Whiteman JP, Amstrup SC, Richardson E, Wilson RR, Ben-David M. Increased Arctic sea ice drift alters adult female polar bear movements and energetics. GLOBAL CHANGE BIOLOGY 2017; 23:3460-3473. [PMID: 28586523 DOI: 10.1111/gcb.13746] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Revised: 03/17/2017] [Accepted: 04/13/2017] [Indexed: 06/07/2023]
Abstract
Recent reductions in thickness and extent have increased drift rates of Arctic sea ice. Increased ice drift could significantly affect the movements and the energy balance of polar bears (Ursus maritimus) which forage, nearly exclusively, on this substrate. We used radio-tracking and ice drift data to quantify the influence of increased drift on bear movements, and we modeled the consequences for energy demands of adult females in the Beaufort and Chukchi seas during two periods with different sea ice characteristics. Westward and northward drift of the sea ice used by polar bears in both regions increased between 1987-1998 and 1999-2013. To remain within their home ranges, polar bears responded to the higher westward ice drift with greater eastward movements, while their movements north in the spring and south in fall were frequently aided by ice motion. To compensate for more rapid westward ice drift in recent years, polar bears covered greater daily distances either by increasing their time spent active (7.6%-9.6%) or by increasing their travel speed (8.5%-8.9%). This increased their calculated annual energy expenditure by 1.8%-3.6% (depending on region and reproductive status), a cost that could be met by capturing an additional 1-3 seals/year. Polar bears selected similar habitats in both periods, indicating that faster drift did not alter habitat preferences. Compounding reduced foraging opportunities that result from habitat loss; changes in ice drift, and associated activity increases, likely exacerbate the physiological stress experienced by polar bears in a warming Arctic.
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Affiliation(s)
- George M Durner
- U.S. Geological Survey, Alaska Science Center, Anchorage, AK, USA
| | - David C Douglas
- U.S. Geological Survey, Alaska Science Center, Juneau, AK, USA
| | - Shannon E Albeke
- Wyoming Geographic Information Science Center, University of Wyoming, Laramie, WY, USA
| | - John P Whiteman
- Department of Zoology and Physiology, University of Wyoming, Laramie, WY, USA
| | | | - Evan Richardson
- Environment and Climate Change Canada, University of Alberta, Edmonton, AB, Canada
| | - Ryan R Wilson
- U.S. Fish and Wildlife Service, Marine Mammals Management, Anchorage, AK, USA
| | - Merav Ben-David
- Department of Zoology and Physiology, University of Wyoming, Laramie, WY, USA
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McKinney MA, Atwood TC, Pedro S, Peacock E. Ecological Change Drives a Decline in Mercury Concentrations in Southern Beaufort Sea Polar Bears. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2017; 51:7814-7822. [PMID: 28612610 DOI: 10.1021/acs.est.7b00812] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We evaluated total mercury (THg) concentrations and trends in polar bears from the southern Beaufort Sea subpopulation from 2004 to 2011. Hair THg concentrations ranged widely among individuals from 0.6 to 13.3 μg g-1 dry weight (mean: 3.5 ± 0.2 μg g-1). Concentrations differed among sex and age classes: solitary adult females ≈ adult females with cubs ≈ subadults > adult males ≈ yearlings > cubs-of-the-year ≈ 2 year old dependent cubs. No variation was observed between spring and fall samples. For spring-sampled adults, THg concentrations declined by 13% per year, contrasting recent trends observed for other Western Hemispheric Arctic biota. Concentrations also declined by 15% per year considering adult males only, while a slower, nonsignificant decrease of 4.4% per year was found for adult females. Lower THg concentrations were associated with higher body mass index (BMI) and higher proportions of lower trophic position food resources consumed. Because BMI and diet were related, and the relationship to THg was strongest for BMI, trends were re-evaluated adjusting for BMI as the covariate. The adjusted annual decline was not significant. These findings indicate that changes in foraging ecology, not declining environmental concentrations of mercury, are driving short-term declines in THg concentrations in southern Beaufort Sea polar bears.
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Affiliation(s)
- Melissa A McKinney
- Wildlife and Fisheries Conservation Center, Department of Natural Resources and the Environment and Center for Environmental Sciences and Engineering, University of Connecticut , Storrs, Connecticut 06269, United States
| | - Todd C Atwood
- United States Geological Survey, Alaska Science Center , Anchorage, Alaska 99508, United States
| | - Sara Pedro
- Wildlife and Fisheries Conservation Center, Department of Natural Resources and the Environment and Center for Environmental Sciences and Engineering, University of Connecticut , Storrs, Connecticut 06269, United States
| | - Elizabeth Peacock
- United States Geological Survey, Alaska Science Center , Anchorage, Alaska 99508, United States
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Wilder JM, Vongraven D, Atwood T, Hansen B, Jessen A, Kochnev A, York G, Vallender R, Hedman D, Gibbons M. Polar bear attacks on humans: Implications of a changing climate. WILDLIFE SOC B 2017. [DOI: 10.1002/wsb.783] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- James M. Wilder
- U.S. Fish and Wildlife Service, Marine Mammals Management; 1011 E. Tudor Road Anchorage AK 99503 USA
| | - Dag Vongraven
- Norwegian Polar Institute, Fram Center; N-9296 Tromsø Norway
| | - Todd Atwood
- U.S. Geological Survey, Alaska Science Center; 4210 University Road Anchorage AK 99508 USA
| | - Bob Hansen
- Government of Nunavut; Igloolik NU X0A 0L0 Canada
| | - Amalie Jessen
- Government of Greenland, Department of Wildlife and Agriculture; P.O. Box 269 3900 Nuuk Greenland
| | - Anatoly Kochnev
- Russian Academy of Sciences, Far East Branch, Institute of Biological Problems of the North, Mammals Ecology Lab; 18 Portovaya Street 685000 Magadan Russia
| | - Geoff York
- Polar Bears International; PO Box 3008 Bozeman MT 59772 USA
| | - Rachel Vallender
- Canadian Wildlife Service, Environment Canada; 351 St. Joseph Boulevard Gatineau QC K1A 0H3 Canada
| | - Daryll Hedman
- Manitoba Conservation and Water Stewardship; Northeast Region, Box 28 Thompson MB R8N 1N2 Canada
| | - Melissa Gibbons
- Wapusk National Park and Manitoba North National Historic Sites, Parks Canada; Box 127 Churchill MB R0B 0E0 Canada
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31
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Regehr EV, Wilson RR, Rode KD, Runge MC, Stern HL. Harvesting wildlife affected by climate change: a modelling and management approach for polar bears. J Appl Ecol 2017; 54:1534-1543. [PMID: 29081540 PMCID: PMC5637955 DOI: 10.1111/1365-2664.12864] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2016] [Accepted: 12/22/2016] [Indexed: 11/29/2022]
Abstract
The conservation of many wildlife species requires understanding the demographic effects of climate change, including interactions between climate change and harvest, which can provide cultural, nutritional or economic value to humans.We present a demographic model that is based on the polar bear Ursus maritimus life cycle and includes density-dependent relationships linking vital rates to environmental carrying capacity (K). Using this model, we develop a state-dependent management framework to calculate a harvest level that (i) maintains a population above its maximum net productivity level (MNPL; the population size that produces the greatest net increment in abundance) relative to a changing K, and (ii) has a limited negative effect on population persistence.Our density-dependent relationships suggest that MNPL for polar bears occurs at approximately 0·69 (95% CI = 0·63-0·74) of K. Population growth rate at MNPL was approximately 0·82 (95% CI = 0·79-0·84) of the maximum intrinsic growth rate, suggesting relatively strong compensation for human-caused mortality.Our findings indicate that it is possible to minimize the demographic risks of harvest under climate change, including the risk that harvest will accelerate population declines driven by loss of the polar bear's sea-ice habitat. This requires that (i) the harvest rate - which could be 0 in some situations - accounts for a population's intrinsic growth rate, (ii) the harvest rate accounts for the quality of population data (e.g. lower harvest when uncertainty is large), and (iii) the harvest level is obtained by multiplying the harvest rate by an updated estimate of population size. Environmental variability, the sex and age of removed animals and risk tolerance can also affect the harvest rate. Synthesis and applications. We present a coupled modelling and management approach for wildlife that accounts for climate change and can be used to balance trade-offs among multiple conservation goals. In our example application to polar bears experiencing sea-ice loss, the goals are to maintain population viability while providing continued opportunities for subsistence harvest. Our approach may be relevant to other species for which near-term management is focused on human factors that directly influence population dynamics within the broader context of climate-induced habitat degradation.
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Affiliation(s)
- Eric V Regehr
- U.S. Fish and Wildlife Service Anchorage AK USA.,Present address: University of Washington Seattle WA USA
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Pagano AM, Rode KD, Cutting A, Owen MA, Jensen S, Ware JV, Robbins CT, Durner GM, Atwood TC, Obbard ME, Middel KR, Thiemann GW, Williams TM. Using tri-axial accelerometers to identify wild polar bear behaviors. ENDANGER SPECIES RES 2017. [DOI: 10.3354/esr00779] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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33
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Implications of Rapid Environmental Change for Polar Bear Behavior and Sociality. MARINE MAMMAL WELFARE 2017. [DOI: 10.1007/978-3-319-46994-2_24] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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Regehr EV, Laidre KL, Akçakaya HR, Amstrup SC, Atwood TC, Lunn NJ, Obbard M, Stern H, Thiemann GW, Wiig Ø. Conservation status of polar bears (Ursus maritimus) in relation to projected sea-ice declines. Biol Lett 2016; 12:20160556. [PMID: 27928000 PMCID: PMC5206583 DOI: 10.1098/rsbl.2016.0556] [Citation(s) in RCA: 93] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Accepted: 10/21/2016] [Indexed: 11/12/2022] Open
Abstract
Loss of Arctic sea ice owing to climate change is the primary threat to polar bears throughout their range. We evaluated the potential response of polar bears to sea-ice declines by (i) calculating generation length (GL) for the species, which determines the timeframe for conservation assessments; (ii) developing a standardized sea-ice metric representing important habitat; and (iii) using statistical models and computer simulation to project changes in the global population under three approaches relating polar bear abundance to sea ice. Mean GL was 11.5 years. Ice-covered days declined in all subpopulation areas during 1979-2014 (median -1.26 days year-1). The estimated probabilities that reductions in the mean global population size of polar bears will be greater than 30%, 50% and 80% over three generations (35-41 years) were 0.71 (range 0.20-0.95), 0.07 (range 0-0.35) and less than 0.01 (range 0-0.02), respectively. According to IUCN Red List reduction thresholds, which provide a common measure of extinction risk across taxa, these results are consistent with listing the species as vulnerable. Our findings support the potential for large declines in polar bear numbers owing to sea-ice loss, and highlight near-term uncertainty in statistical projections as well as the sensitivity of projections to different plausible assumptions.
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Affiliation(s)
- Eric V Regehr
- Marine Mammals Management, US Fish and Wildlife Service, Anchorage, AK 99503, USA
| | - Kristin L Laidre
- Polar Science Center, Applied Physics Laboratory, University of Washington, Seattle, WA 98105, USA
| | - H Resit Akçakaya
- Department of Ecology and Evolution, Stony Brook University, Stony Brook, NY 11794, USA
| | | | - Todd C Atwood
- Alaska Science Center, US Geological Survey, Anchorage, AK 99508, USA
| | - Nicholas J Lunn
- Environment and Climate Change Canada, Edmonton, Alberta, Canada T6G 2E9
| | - Martyn Obbard
- Ontario Ministry of Natural Resources and Forestry, Peterborough, Ontario, Canada K9J 7B8
| | - Harry Stern
- Polar Science Center, Applied Physics Laboratory, University of Washington, Seattle, WA 98105, USA
| | - Gregory W Thiemann
- Faculty of Environmental Studies, York University, Toronto, Ontario, Canada M3J 1P3
| | - Øystein Wiig
- Natural History Museum, University of Oslo, Oslo 0318, Norway
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