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Thompson PR, Harrington PD, Mallory CD, Lele SR, Bayne EM, Derocher AE, Edwards MA, Campbell M, Lewis MA. Simultaneous estimation of the temporal and spatial extent of animal migration using step lengths and turning angles. Mov Ecol 2024; 12:1. [PMID: 38191509 PMCID: PMC10775566 DOI: 10.1186/s40462-023-00444-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Accepted: 12/19/2023] [Indexed: 01/10/2024]
Abstract
BACKGROUND Animals of many different species, trophic levels, and life history strategies migrate, and the improvement of animal tracking technology allows ecologists to collect increasing amounts of detailed data on these movements. Understanding when animals migrate is important for managing their populations, but is still difficult despite modelling advancements. METHODS We designed a model that parametrically estimates the timing of migration from animal tracking data. Our model identifies the beginning and end of migratory movements as signaled by change-points in step length and turning angle distributions. To this end, we can also use the model to estimate how an animal's movement changes when it begins migrating. In addition to a thorough simulation analysis, we tested our model on three datasets: migratory ferruginous hawks (Buteo regalis) in the Great Plains, barren-ground caribou (Rangifer tarandus groenlandicus) in northern Canada, and non-migratory brown bears (Ursus arctos) from the Canadian Arctic. RESULTS Our simulation analysis suggests that our model is most useful for datasets where an increase in movement speed or directional autocorrelation is clearly detectable. We estimated the beginning and end of migration in caribou and hawks to the nearest day, while confirming a lack of migratory behaviour in the brown bears. In addition to estimating when caribou and ferruginous hawks migrated, our model also identified differences in how they migrated; ferruginous hawks achieved efficient migrations by drastically increasing their movement rates while caribou migration was achieved through significant increases in directional persistence. CONCLUSIONS Our approach is applicable to many animal movement studies and includes parameters that can facilitate comparison between different species or datasets. We hope that rigorous assessment of migration metrics will aid understanding of both how and why animals move.
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Affiliation(s)
- Peter R Thompson
- Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada.
| | - Peter D Harrington
- Department of Mathematics, University of British Columbia, Vancouver, BC, Canada
- Department of Mathematical and Statistical Sciences, University of Alberta, Edmonton, AB, Canada
| | | | - Subhash R Lele
- Department of Mathematical and Statistical Sciences, University of Alberta, Edmonton, AB, Canada
| | - Erin M Bayne
- Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada
| | - Andrew E Derocher
- Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada
| | - Mark A Edwards
- Office of the Chief Scientist, Environment and Protected Areas, Government of Alberta, Edmonton, AB, Canada
- Department of Renewable Resources, 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
- Department of Biology, University of Victoria, Victoria, BC, Canada
- Department of Mathematics and Statistics, University of Victoria, Victoria, BC, Canada
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Tidière M, Colchero F, Staerk J, Adkesson MJ, Andersen DH, Bland L, Böye M, Brando S, Clegg I, Cubaynes S, Cutting A, De Man D, Derocher AE, Dorsey C, Elgar W, Gaglione E, Anderson Hansen K, Jungheim A, Kok J, Laule G, Goya AL, Miller L, Monreal-Pawlowsky T, Mucha K, Owen MA, Petersen SD, Pilfold N, Richardson D, Richardson ES, Sabo D, Sato N, Shellabarger W, Skovlund CR, Tomisawa K, Trautwein SE, Van Bonn W, Van Elk C, Von Fersen L, Wahlberg M, Zhang P, Zhang X, Conde DA. Survival improvements of marine mammals in zoological institutions mirror historical advances in human longevity. Proc Biol Sci 2023; 290:20231895. [PMID: 37848064 PMCID: PMC10581765 DOI: 10.1098/rspb.2023.1895] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Accepted: 09/21/2023] [Indexed: 10/19/2023] Open
Abstract
An intense public debate has fuelled governmental bans on marine mammals held in zoological institutions. The debate rests on the assumption that survival in zoological institutions has been and remains lower than in the wild, albeit the scientific evidence in support of this notion is equivocal. Here, we used statistical methods previously applied to assess historical improvements in human lifespan and data on 8864 individuals of four marine mammal species (harbour seal, Phoca vitulina; California sea lion, Zalophus californianus; polar bear, Ursus maritimus; common bottlenose dolphin, Tursiops truncatus) held in zoos from 1829 to 2020. We found that life expectancy increased up to 3.40 times, and first-year mortality declined up to 31%, during the last century in zoos. Moreover, the life expectancy of animals in zoos is currently 1.65-3.55 times longer than their wild counterparts. Like humans, these improvements have occurred concurrently with advances in management practices, crucial for population welfare. Science-based decisions will help effective legislative changes and ensure better implementation of animal care.
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Affiliation(s)
- Morgane Tidière
- Interdisciplinary Centre on Population Dynamics (CPop), University of Southern Denmark, Odense, Denmark
- Department of Biology, University of Southern Denmark, Campusvej 55, 5230 Odense, Denmark
- Conservation and Science Department, Species360, 7900 International Drive, Suite 300, Minneapolis, MN 55425, USA
| | - Fernando Colchero
- Interdisciplinary Centre on Population Dynamics (CPop), University of Southern Denmark, Odense, Denmark
- Department of Mathematics and Computer Science, University of Southern Denmark, Odense, Denmark
- Department of Primate Behavior and Evolution, Max Planck Institute for Evolutionary Anthropology, Deutscher Pl. 6, 04103 Leipzig, Germany
| | - Johanna Staerk
- Interdisciplinary Centre on Population Dynamics (CPop), University of Southern Denmark, Odense, Denmark
- Department of Biology, University of Southern Denmark, Campusvej 55, 5230 Odense, Denmark
- Conservation and Science Department, Species360, 7900 International Drive, Suite 300, Minneapolis, MN 55425, USA
| | | | - Ditte H. Andersen
- Department of Biology, University of Southern Denmark, Campusvej 55, 5230 Odense, Denmark
| | - Lucie Bland
- Conservation and Science Department, Species360, 7900 International Drive, Suite 300, Minneapolis, MN 55425, USA
- Eureka Publishing, Thornbury, Australia
| | - Martin Böye
- Centre de Recherche et d'Etude pour l'Animal Sauvage, Planète Sauvage, 44710 Port Saint Pere, France
| | - Sabrina Brando
- AnimalConcepts, PO Box 378, 03725 Teulada, Alicante, Spain
| | - Isabella Clegg
- Animal Welfare Expertise, The Knoll, Woodlands, Combe Martin, EX34 0ATLittleton Manor, Winchester SO22 6QU, UK
| | - Sarah Cubaynes
- CEFE, Univ Montpellier, CNRS, EPHE-PSL University, IRD, Montpellier, France
| | - Amy Cutting
- Polar Bear International, PO Box 3008, Bozeman, MT, USA
| | - Danny De Man
- European Association of Zoos and Aquaria (EAZA), Plantage Middelaan 45, 1018-DC Amsterdam, The Netherlands
| | - Andrew E. Derocher
- Department of Biological Sciences, University of Alberta; Edmonton, Alberta, Canada T6G 2E9
| | - Candice Dorsey
- Association of Zoos and Aquariums, 8403 Colesville Road Ste 710, Silver Spring, MD 20910, USA
| | - William Elgar
- Zoo Miami, 12400 SW 152 Street, Miami, FL 33177, USA
| | - Eric Gaglione
- Georgia Aquarium, 225 Baker Street, Atlanta, GA 30313, USA
| | - Kirstin Anderson Hansen
- Department of Biology, University of Southern Denmark, Campusvej 55, 5230 Odense, Denmark
- Marine Biological Research Center, University of Southern Denmark, Hindsholmvej 11, 5300 Kerteminde, Denmark
| | - Allison Jungheim
- Como Park Zoo and Conservatory, 1225 Estabrook Dr., Saint Paul, MN 55103, USA
| | - José Kok
- Ouwehands Zoo, Grebbeweg 111, 3911 AV Rhenen, The Netherlands
| | - Gail Laule
- Mandai Wildlife Group, 80 Mandai Lake Road, Singapore 729826
| | | | - Lance Miller
- Chicago Zoological Society, Brookfield Zoo, Brookfield, IL, USA
| | | | - Katelyn Mucha
- Conservation and Science Department, Species360, 7900 International Drive, Suite 300, Minneapolis, MN 55425, USA
| | - Megan A. Owen
- San Diego Zoo Wildlife Alliance, 15600 San Pasqual Valley Rd., Escondido, CA, USA
| | | | - Nicholas Pilfold
- San Diego Zoo Wildlife Alliance, 15600 San Pasqual Valley Rd., Escondido, CA, USA
| | - Douglas Richardson
- Zoological Consultancy Ltd, Columba Cottage, Mill Rd, Kingussie PH21 1LF, UK
- EAZA Polar Bear EEP, Amsterdam, Netherlands
| | - Evan S. Richardson
- Environment and Climate Change Canada, Unit 150–234 Donald Street, Winnipeg, Manitoba R3C 1M8, Canada
| | - Devon Sabo
- Columbus Zoo and Aquarium, 4850 W. Powell Road, PO Box 400, Powell, OH 43065-0400, USA
| | - Nobutaka Sato
- Asahiyama Zoological Park, Kuranuma, Higasiasahikawacho, Asahikawa city, Japan
| | | | - Cecilie R. Skovlund
- Conservation, Copenhagen Zoo, Roskildevej 38, 2000 Frederiksberg, Denmark
- Section of Animal Welfare and Disease Control, Department of Veterinary and Animal Sciences, University of Copenhagen, Grønnegårdsvej 8, 1870 Frederiksberg, Denmark
| | - Kanako Tomisawa
- Omuta City Zoo, 163 Showa-machi, Omuta, Fukuoka 836-0871, Japan
| | - Sandra E. Trautwein
- Conservation and Science Department, Species360, 7900 International Drive, Suite 300, Minneapolis, MN 55425, USA
| | - William Van Bonn
- A. Watson Armour III, Center for Animal Health and Welfare, Animal Care and Science Division, John G. Shedd Aquarium, Chicago, IL 60605, USA
| | - Cornelis Van Elk
- Independent practitioner, Arendsweg 98, Enschede 7544RM, The Netherlands
| | | | - Magnus Wahlberg
- Department of Biology, University of Southern Denmark, Campusvej 55, 5230 Odense, Denmark
- Marine Biological Research Center, University of Southern Denmark, Hindsholmvej 11, 5300 Kerteminde, Denmark
| | - Peijun Zhang
- Mammal and Marine Bioacoustics Laboratory Institute of Deep-sea Science and Engineering, Chinese Academy of Sciences, Sanya 572000, People's Republic of China
| | - Xianfeng Zhang
- Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, People's Republic of China
| | - Dalia A. Conde
- Interdisciplinary Centre on Population Dynamics (CPop), University of Southern Denmark, Odense, Denmark
- Department of Biology, University of Southern Denmark, Campusvej 55, 5230 Odense, Denmark
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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. Ecol Appl 2023; 33:e2751. [PMID: 36151883 DOI: 10.1002/eap.2751] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [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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Togunov RR, Derocher AE, Lunn NJ, Auger-Méthé M. Drivers of polar bear behavior and the possible effects of prey availability on foraging strategy. Mov Ecol 2022; 10:50. [PMID: 36384775 PMCID: PMC9670556 DOI: 10.1186/s40462-022-00351-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Accepted: 11/09/2022] [Indexed: 06/05/2023]
Abstract
BACKGROUND Change in behavior is one of the earliest responses to variation in habitat suitability. It is therefore important to understand the conditions that promote different behaviors, particularly in areas undergoing environmental change. Animal movement is tightly linked to behavior and remote tracking can be used to study ethology when direct observation is not possible. METHODS We used movement data from 14 polar bears (Ursus maritimus) in Hudson Bay, Canada, during the foraging season (January-June), when bears inhabit the sea ice. We developed an error-tolerant method to correct for sea ice drift in tracking data. Next, we used hidden Markov models with movement and orientation relative to wind to study three behaviors (stationary, area-restricted search, and olfactory search) and examine effects of 11 covariates on behavior. RESULTS Polar bears spent approximately 47% of their time in the stationary drift state, 29% in olfactory search, and 24% in area-restricted search. High energy behaviors occurred later in the day (around 20:00) compared to other populations. Second, olfactory search increased as the season progressed, which may reflect a shift in foraging strategy from still-hunting to active search linked to a shift in seal availability (i.e., increase in haul-outs from winter to the spring pupping and molting seasons). Last, we found spatial patterns of distribution linked to season, ice concentration, and bear age that may be tied to habitat quality and competitive exclusion. CONCLUSIONS Our observations were generally consistent with predictions of the marginal value theorem, and differences between our findings and other populations could be explained by regional or temporal variation in resource availability. Our novel movement analyses and finding can help identify periods, regions, and conditions of critical habitat.
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Affiliation(s)
- Ron R. Togunov
- Institute for the Oceans and Fisheries, The University of British Columbia, V6T 1Z4 Vancouver, Canada
- Department of Zoology, The University of British Columbia, Vancouver, V6T 1Z4 Canada
| | - Andrew E. Derocher
- Department of Biological Sciences, University of Alberta, Edmonton, T6G 2E9 Canada
| | - Nicholas J. Lunn
- Wildlife Research Division, Science and Technology Branch, Environment and Climate Change Canada, Edmonton, T6G 2E9 Canada
| | - Marie Auger-Méthé
- Institute for the Oceans and Fisheries, The University of British Columbia, V6T 1Z4 Vancouver, Canada
- Department of Statistics, The University of British Columbia, Vancouver, V6T 1Z4 Canada
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5
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Dietz R, Letcher RJ, Aars J, Andersen M, Boltunov A, Born EW, Ciesielski TM, Das K, Dastnai S, Derocher AE, Desforges JP, Eulaers I, Ferguson S, Hallanger IG, Heide-Jørgensen MP, Heimbürger-Boavida LE, Hoekstra PF, Jenssen BM, Kohler SG, Larsen MM, Lindstrøm U, Lippold A, Morris A, Nabe-Nielsen J, Nielsen NH, Peacock E, Pinzone M, Rigét FF, Rosing-Asvid A, Routti H, Siebert U, Stenson G, Stern G, Strand J, Søndergaard J, Treu G, Víkingsson GA, Wang F, Welker JM, Wiig Ø, Wilson SJ, Sonne C. A risk assessment review of mercury exposure in Arctic marine and terrestrial mammals. Sci Total Environ 2022; 829:154445. [PMID: 35304145 DOI: 10.1016/j.scitotenv.2022.154445] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Revised: 02/25/2022] [Accepted: 03/06/2022] [Indexed: 06/14/2023]
Abstract
There has been a considerable number of reports on Hg concentrations in Arctic mammals since the last Arctic Monitoring and Assessment Programme (AMAP) effort to review biological effects of the exposure to mercury (Hg) in Arctic biota in 2010 and 2018. Here, we provide an update on the state of the knowledge of health risk associated with Hg concentrations in Arctic marine and terrestrial mammal species. Using available population-specific data post-2000, our ultimate goal is to provide an updated evidence-based estimate of the risk for adverse health effects from Hg exposure in Arctic mammal species at the individual and population level. Tissue residues of Hg in 13 species across the Arctic were classified into five risk categories (from No risk to Severe risk) based on critical tissue concentrations derived from experimental studies on harp seals and mink. Exposure to Hg lead to low or no risk for health effects in most populations of marine and terrestrial mammals, however, subpopulations of polar bears, pilot whales, narwhals, beluga and hooded seals are highly exposed in geographic hotspots raising concern for Hg-induced toxicological effects. About 6% of a total of 3500 individuals, across different marine mammal species, age groups and regions, are at high or severe risk of health effects from Hg exposure. The corresponding figure for the 12 terrestrial species, regions and age groups was as low as 0.3% of a total of 731 individuals analyzed for their Hg loads. Temporal analyses indicated that the proportion of polar bears at low or moderate risk has increased in East/West Greenland and Western Hudson Bay, respectively. However, there remain numerous knowledge gaps to improve risk assessments of Hg exposure in Arctic mammalian species, including the establishment of improved concentration thresholds and upscaling to the assessment of population-level effects.
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Affiliation(s)
- Rune Dietz
- Aarhus University, Arctic Research Centre (ARC), Department of Ecoscience, P.O. Box 358, DK-4000 Roskilde, Denmark.
| | - Robert J Letcher
- Ecotoxicology and Wildlife Health Division, Environment and Climate Change Canada, National Wildlife Research Centre, Carleton University, Ottawa, ON K1A 0H3, Canada.
| | - Jon Aars
- Norwegian Polar Institute, Tromsø NO-9296, Norway
| | | | - Andrei Boltunov
- Marine Mammal Research and Expedition Centre, 36 Nahimovskiy pr., Moscow 117997, Russia
| | - Erik W Born
- Greenland Institute of Natural Resources, P.O. Box 570, DK-3900 Nuuk, Greenland
| | - Tomasz M Ciesielski
- Department of Biology, Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
| | - Krishna Das
- Freshwater and Oceanic sciences Unit of reSearch (FOCUS), University of Liege, 4000 Liege, Belgium
| | - Sam Dastnai
- Aarhus University, Arctic Research Centre (ARC), Department of Ecoscience, P.O. Box 358, DK-4000 Roskilde, Denmark
| | - Andrew E Derocher
- Department of Biological Sciences, University of Alberta, Edmonton, AB T6G 2E9, Canada
| | - Jean-Pierre Desforges
- Aarhus University, Arctic Research Centre (ARC), Department of Ecoscience, P.O. Box 358, DK-4000 Roskilde, Denmark; Department of Environmental Studies and Science, University of Winnipeg, Winnipeg, MB, Canada
| | - Igor Eulaers
- Aarhus University, Arctic Research Centre (ARC), Department of Ecoscience, P.O. Box 358, DK-4000 Roskilde, Denmark; Norwegian Polar Institute, Tromsø NO-9296, Norway
| | - Steve Ferguson
- Fisheries and Oceans Canada, 501 University Crescent, Winnipeg, MB R3T 2N6, Canada; Department of Biological Sciences, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| | | | | | - Lars-Eric Heimbürger-Boavida
- Géosciences Environnement Toulouse, CNRS/IRD/Université Paul Sabatier Toulouse III, Toulouse, France; Aix Marseille Université, CNRS/INSU, Université de Toulon, IRD, Mediterranean Institute of Oceanography (MIO) UM 110, Marseille, France
| | | | - Bjørn M Jenssen
- Aarhus University, Arctic Research Centre (ARC), Department of Ecoscience, P.O. Box 358, DK-4000 Roskilde, Denmark; Department of Biology, Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
| | - Stephen Gustav Kohler
- Department of Chemistry, Norwegian University of Science and Technology, Realfagbygget, E2-128, Gløshaugen, NO-7491 Trondheim, Norway
| | - Martin M Larsen
- Aarhus University, Arctic Research Centre (ARC), Department of Ecoscience, P.O. Box 358, DK-4000 Roskilde, Denmark
| | - Ulf Lindstrøm
- Department of Arctic and Marine Biology, UiT The Arctic University of Norway, NO-9037 Tromsø, Norway; Department of Arctic Technology, Institute of Marine Research, FRAM Centre, NO-9007 Tromsø, Norway
| | - Anna Lippold
- Norwegian Polar Institute, Tromsø NO-9296, Norway
| | - Adam Morris
- Northern Contaminants Program, Crown-Indigenous Relations and Northern Affairs Canada, 15 Eddy Street, 14th floor, Gatineau, Quebec K1A 0H4, Canada
| | - Jacob Nabe-Nielsen
- Aarhus University, Arctic Research Centre (ARC), Department of Ecoscience, P.O. Box 358, DK-4000 Roskilde, Denmark
| | - Nynne H Nielsen
- Greenland Institute of Natural Resources, P.O. Box 570, DK-3900 Nuuk, Greenland
| | - Elizabeth Peacock
- USGS Alaska Science Center, 4210 University Dr., Anchorage, AK 99508-4626, USA
| | - Marianna Pinzone
- Department of Environmental Studies and Science, University of Winnipeg, Winnipeg, MB, Canada
| | - Frank F Rigét
- Aarhus University, Arctic Research Centre (ARC), Department of Ecoscience, P.O. Box 358, DK-4000 Roskilde, Denmark
| | - Aqqalu Rosing-Asvid
- Greenland Institute of Natural Resources, P.O. Box 570, DK-3900 Nuuk, Greenland
| | - Heli Routti
- Norwegian Polar Institute, Tromsø NO-9296, Norway
| | - Ursula Siebert
- Institute for Terrestrial and Aquatic Wildlife Research, University of Veterinary Medicine Hannover, Foundation, Werftstr. 6, DE-25761 Büsum, Germany
| | - Garry Stenson
- Northwest Atlantic Fisheries Centre, Department DFO-MPO, 80 EastWhite Hills vie, St John's A1C 5X1, Newfoundland and Labrador, Canada
| | - Gary Stern
- Centre for Earth Observation Sciences (CEOS), Clayton H. Riddell Faculty of Environment, Earth and Resources, University of Manitoba, 586Wallace Bld, 125 Dysart Rd., Winnipeg, Manitoba R3T, 2N2, Canada
| | - Jakob Strand
- Aarhus University, Arctic Research Centre (ARC), Department of Ecoscience, P.O. Box 358, DK-4000 Roskilde, Denmark
| | - Jens Søndergaard
- Aarhus University, Arctic Research Centre (ARC), Department of Ecoscience, P.O. Box 358, DK-4000 Roskilde, Denmark
| | - Gabriele Treu
- Leibniz Institute for Zoo and Wildlife Research, Alfred-Kowalke-Str. 17, 10315 Berlin, Germany
| | - Gisli A Víkingsson
- Marine and Freshwater Research Institute, Skúlagata 4, 101 Reykjavík, Iceland
| | - Feiyue Wang
- Centre for Earth Observation Sciences (CEOS), Clayton H. Riddell Faculty of Environment, Earth and Resources, University of Manitoba, 586Wallace Bld, 125 Dysart Rd., Winnipeg, Manitoba R3T, 2N2, Canada
| | - Jeffrey M Welker
- University of Alaska Anchorage, Anchorage 99508, United States; University of Oulu, Oulu 90014, Finland; University of the Arctic, Rovaniemi 96460, Finland
| | - Øystein Wiig
- Natural History Museum, University of Oslo, P.O. Box 1172, Blindern, N-0318 Oslo, Norway
| | - Simon J Wilson
- Arctic Monitoring and Assessment Programme (AMAP) Secretariat, Box 6606 Stakkevollan, N-9296 Tromsø, Norway
| | - Christian Sonne
- Aarhus University, Arctic Research Centre (ARC), Department of Ecoscience, P.O. Box 358, DK-4000 Roskilde, Denmark
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Vongraven D, Derocher AE, Pilfold NW, Yoccoz NG. Polar Bear Harvest Patterns Across the Circumpolar Arctic. Front Conserv Sci 2022. [DOI: 10.3389/fcosc.2022.836544] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Wildlife harvest remains a conservation concern for many species and assessing patterns of harvest can provide insights on sustainability and inform management. Polar bears (Ursus maritimus) are harvested over a large part of their range by local people. The species has a history of unsustainable harvest that was largely rectified by an international agreement that required science-based management. The objective of our study was to examine the temporal patterns in the number of polar bears harvested, harvest sex ratios, and harvest rates from 1970 to 2018. We analyzed data from 39,049 harvested polar bears (annual mean 797 bears) collected from 1970 to 2018. Harvest varied across populations and times that reflect varying management objectives, episodic events, and changes based on new population estimates. More males than females were harvested with an overall M:F sex ratio of 1.84. Harvest varied by jurisdiction with 68.0% of bears harvested in Canada, 18.0% in Greenland, 11.8% in the USA, and 2.2% in Norway. Harvest rate was often near the 4.5% target rate. Where data allowed harvest rate estimation, the target rate was exceeded in 11 of 13 populations with 1–5 populations per year above the target since 1978. Harvest rates at times were up to 15.9% of the estimated population size suggesting rare episodes of severe over-harvest. Harvest rate was unrelated to a proxy for ecosystem productivity (area of continental shelf within each population) but was correlated with prey diversity. In the last 5–10 years, monitored populations all had harvest rates near sustainable limits, suggesting improvements in management. Polar bear harvest management has reduced the threat it once posed to the species. However, infrequent estimates of abundance, new management objectives, and climate change have raised new concerns about the effects of harvest.
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Thompson PR, Lewis MA, Edwards MA, Derocher AE. Time-dependent memory and individual variation in Arctic brown bears (Ursus arctos). Mov Ecol 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] [What about the content of this article? (0)] [Affiliation(s)] [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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8
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Klappstein NJ, Potts JR, Michelot T, Börger L, Pilfold NW, Lewis MA, Derocher AE. Energy‐based step selection analysis: modelling the energetic drivers of animal movement and habitat use. J Anim Ecol 2022; 91:946-957. [DOI: 10.1111/1365-2656.13687] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Accepted: 02/17/2022] [Indexed: 11/30/2022]
Affiliation(s)
| | - Jonathan R. Potts
- School of Mathematics and Statistics University of Sheffield, Hicks Building, Hounsfield Road Sheffield UK
| | - Théo Michelot
- Centre for Research into Ecological and Environmental Modelling University of St Andrews St Andrews UK
| | - Luca Börger
- Department of Biosciences Swansea University Swansea UK
- Centre for Biomathematics, College of Science Swansea University Swansea UK
| | - Nicholas W. Pilfold
- Conservation Science and Wildlife Health, San Diego Zoo Wildlife Alliance San Diego USA
| | - Mark A. Lewis
- Department of Biological Sciences University of Alberta Edmonton Canada
- Department of Mathematical and Statistical Sciences University of Alberta Edmonton Canada
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9
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Thompson PR, Derocher AE, Edwards MA, Lewis MA. Detecting seasonal episodic‐like spatio‐temporal memory patterns using animal movement modelling. Methods Ecol Evol 2021. [DOI: 10.1111/2041-210x.13743] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Peter R. Thompson
- Department of Biological Sciences University of Alberta Edmonton AB Canada
| | - Andrew E. Derocher
- Department of Biological 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
| | - 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
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10
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Maduna SN, Aars J, Fløystad I, Klütsch CFC, Zeyl Fiskebeck EML, Wiig Ø, Ehrich D, Andersen M, Bachmann L, Derocher AE, Nyman T, Eiken HG, Hagen SB. Sea ice reduction drives genetic differentiation among Barents Sea polar bears. Proc Biol Sci 2021; 288:20211741. [PMID: 34493082 PMCID: PMC8424353 DOI: 10.1098/rspb.2021.1741] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Accepted: 08/12/2021] [Indexed: 12/24/2022] Open
Abstract
Loss of Arctic sea ice owing to climate change is predicted to reduce both genetic diversity and gene flow in ice-dependent species, with potentially negative consequences for their long-term viability. Here, we tested for the population-genetic impacts of reduced sea ice cover on the polar bear (Ursus maritimus) sampled across two decades (1995-2016) from the Svalbard Archipelago, Norway, an area that is affected by rapid sea ice loss in the Arctic Barents Sea. We analysed genetic variation at 22 microsatellite loci for 626 polar bears from four sampling areas within the archipelago. Our results revealed a 3-10% loss of genetic diversity across the study period, accompanied by a near 200% increase in genetic differentiation across regions. These effects may best be explained by a decrease in gene flow caused by habitat fragmentation owing to the loss of sea ice coverage, resulting in increased inbreeding of local polar bears within the focal sampling areas in the Svalbard Archipelago. This study illustrates the importance of genetic monitoring for developing adaptive management strategies for polar bears and other ice-dependent species.
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Affiliation(s)
- Simo Njabulo Maduna
- Norwegian Institute of Bioeconomy Research, Division of Environment and Natural Resources, Svanhovd, N-9925 Svanvik, Norway
| | - Jon Aars
- Norwegian Polar Institute, N-9296 Tromsø, Norway
| | - Ida Fløystad
- Norwegian Institute of Bioeconomy Research, Division of Environment and Natural Resources, Svanhovd, N-9925 Svanvik, Norway
| | - Cornelya F. C. Klütsch
- Norwegian Institute of Bioeconomy Research, Division of Environment and Natural Resources, Svanhovd, N-9925 Svanvik, Norway
| | | | - Øystein Wiig
- Natural History Museum, University of Oslo, N-0318 Oslo, Norway
| | - Dorothee Ehrich
- Department of Arctic and Marine Biology, UiT Arctic University of Tromsø, N-9037 Tromsø, Norway
| | | | - Lutz Bachmann
- Natural History Museum, University of Oslo, N-0318 Oslo, Norway
| | - Andrew E. Derocher
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada T6G 2E9
| | - Tommi Nyman
- Norwegian Institute of Bioeconomy Research, Division of Environment and Natural Resources, Svanhovd, N-9925 Svanvik, Norway
| | - Hans Geir Eiken
- Norwegian Institute of Bioeconomy Research, Division of Environment and Natural Resources, Svanhovd, N-9925 Svanvik, Norway
| | - Snorre B. Hagen
- Norwegian Institute of Bioeconomy Research, Division of Environment and Natural Resources, Svanhovd, N-9925 Svanvik, Norway
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11
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Affiliation(s)
- Ron R. Togunov
- Institute for the Oceans and Fisheries The University of British Columbia Vancouver BC Canada
- Department of Zoology The University of British Columbia Vancouver BC Canada
| | - Andrew E. Derocher
- Department of Biological Sciences University of Alberta Edmonton AB Canada
| | - Nicholas J. Lunn
- Department of Biological Sciences University of Alberta Edmonton AB Canada
- Wildlife Research Division, Science and Technology Branch Environment and Climate Change Canada Edmonton AB Canada
| | - Marie Auger‐Méthé
- Institute for the Oceans and Fisheries The University of British Columbia Vancouver BC Canada
- Department of Statistics University of British Columbia Vancouver BC Canada
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12
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Abstract
Abstract
The space use strategies animals use to acquire resources needed for survival and reproduction reflect life history traits and individual behaviors. For large solitary carnivores, such as cougars (Puma concolor), prey, mates, and safe habitat in which to raise offspring, are resources that influence space use. Most animal home range studies investigate differences between sexes but fail to explore the space use patterns among individuals. We first used 95% minimum convex polygon (MCP), kernel density estimate (KDE), and Brownian bridge estimator (BB), to estimate the home range of 43 cougars satellite-collared in west-central Alberta, Canada, in 2016–2018. We found that adult males (MCP = 498 km2; KDE = 623 km2; BB = 547 km2) had home ranges that were more than twice the size of those of adult females (MCP = 181 km2; KDE = 273 km2; BB = 217 km2). We then used net squared displacement, path segmentation analysis, and multi-response permutation procedure, to examine the space use patterns of 27 female and 16 male cougars. We constructed a decision tree and found that 23% of cougars were dispersers (12% of females and 44% of males), 47% were residents (58% of females and 31% of males), 9% were seasonal home range shifters (12% of females and 6% of males), and 19% shifted to a new area during the study period (19% of females and 19% of males). We learned that dispersers all were subadults, whereas all residents, seasonal shifters, and shifters, were adults, except for one subadult male. Our study provides insights on animal home ranges with methods to categorize different space use strategies which could be used to help assess the dynamics of a population.
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Affiliation(s)
- Corey A Smereka
- Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada
| | - Paul F Frame
- Alberta Environment and Parks, Edmonton, AB, Canada
| | - Mark A Edwards
- Royal Alberta Museum, Edmonton, AB, Canada
- Department of Renewable Resources, University of Alberta, Edmonton, AB, Canada
| | - Owen M Slater
- Faculty of Veterinary Medicine, University of Calgary, Calgary, AB, Canada
| | | | - Andrew E Derocher
- Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada
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13
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Abstract
Abstract
Migration is predicted to change both spatially and temporally as climate change alters seasonal resource availability. Species in extreme environments are especially susceptible to climate change; hence, it is important to determine environmental and biological variables that influence their migration. Polar bears (Ursus maritimus) are an Arctic apex carnivore whose migration phenology has been affected by climate change and is vulnerable to future changes. Here, we used satellite-linked telemetry collar data from adult female polar bears in western Hudson Bay from 2004 to 2016 and multivariate response regression models to demonstrate that 1) spatial and temporal migration metrics are correlated, 2) ice concentration and wind are important environmental variables that influence polar bear migration in seasonal ice areas, and 3) migration did not vary across the years of our study, highlighting the importance of continued monitoring. Specifically, we found that ice concentration, wind speed, and wind direction affected polar bear migration onto ice during freeze-up and ice concentration and wind direction affected migration onto land during breakup. Bears departed from land earlier with increased wind speed and the effect of wind direction on migration may be linked to prey searching and ice drift. Low ice concentration was associated with higher movement during freeze-up and breakup. Our findings suggest that migration movement may increase in response to climate change as ice concentration and access to prey declines, potentially increasing nutritional stress on bears.
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Affiliation(s)
- Alyssa M Bohart
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
| | - Nicholas J Lunn
- Wildlife Research Division, Science and Technology Branch, Environment and Climate Change Canada, University of Alberta, Edmonton, Alberta, Canada
| | - Andrew E Derocher
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
| | - David McGeachy
- Wildlife Research Division, Science and Technology Branch, Environment and Climate Change Canada, University of Alberta, Edmonton, Alberta, Canada
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14
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Johnson AC, Reimer JR, Lunn NJ, Stirling I, McGeachy D, Derocher AE. Influence of sea ice dynamics on population energetics of Western Hudson Bay polar bears. Conserv Physiol 2020; 8:coaa132. [PMID: 33408870 PMCID: PMC7772618 DOI: 10.1093/conphys/coaa132] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Revised: 10/23/2020] [Accepted: 12/07/2020] [Indexed: 05/27/2023]
Abstract
The Arctic marine ecosystem has experienced extensive changes in sea ice dynamics, with significant effects on ice-dependent species such as polar bears (Ursus maritimus). We used annual estimates of the numbers of bears onshore in the core summering area, age/sex structure and body condition data to estimate population energy density and storage energy in Western Hudson Bay polar bears from 1985 to 2018. We examined intra-population variation in energetic patterns, temporal energetic trends and the relationship between population energetics and sea ice conditions. Energy metrics for most demographic classes declined over time in relation to earlier sea ice breakup, most significantly for solitary adult females and subadult males, suggesting their greater vulnerability to nutritional stress than other age/sex classes. Temporal declines in population energy metrics were related to earlier breakup and longer lagged open-water periods, suggesting multi-year effects of sea ice decline. The length of the open-water period ranged from 102 to 166 days and increased significantly by 9.9 days/decade over the study period. Total population energy density and storage energy were significantly lower when sea ice breakup occurred earlier and the lagged open-water period was longer. At the earliest breakup and a lagged open-water period of 180 days, population energy density was predicted to be 33% lower than our minimum estimated energy density and population storage energy was predicted to be 40% lower than the minimum estimated storage energy. Consequently, over the study, the total population energy density declined by 53% (mean: 3668 ± 386 MJ kg-1/decade) and total population storage energy declined by 56% (mean: 435900 ± 46770 MJ/decade). This study provides insights into ecological mechanisms linking population responses to sea ice decline and highlights the significance of maintaining long-term research programs.
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Affiliation(s)
- Amy C Johnson
- Department of Biological Sciences, University of Alberta, Edmonton, AB T6G 2E9, Canada
| | - Jody R Reimer
- Department of Biological Sciences, University of Alberta, Edmonton, AB T6G 2E9, Canada
- Department of Mathematics, University of Utah, Salt Lake City, UT 84112, USA
| | - Nicholas J Lunn
- Environment and Climate Change Canada, CW-422 Biological Sciences Building, University of Alberta, Edmonton, AB T6G 2E9, Canada
| | - Ian Stirling
- Department of Biological Sciences, University of Alberta, Edmonton, AB T6G 2E9, Canada
- Environment and Climate Change Canada, CW-422 Biological Sciences Building, University of Alberta, Edmonton, AB T6G 2E9, Canada
| | - David McGeachy
- Environment and Climate Change Canada, CW-422 Biological Sciences Building, University of Alberta, Edmonton, AB T6G 2E9, Canada
| | - Andrew E Derocher
- Department of Biological Sciences, University of Alberta, Edmonton, AB T6G 2E9, Canada
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15
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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] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
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16
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Smereka CA, Frame PF, Edwards MA, Frame DD, Slater OM, Derocher AE. Seasonal habitat selection of cougars Puma concolor by sex and reproductive state in west-central Alberta, Canada. Wildlife Biology 2020. [DOI: 10.2981/wlb.00735] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
Affiliation(s)
- Corey A. Smereka
- C. A. Smereka (https://orcid.org/0000-0002-1216-4622) ✉ and A. E Derocher, Dept of Biological Sciences, Univ. of Alberta, Edmonton, AB T6G 2E9, Canada
| | - Paul F. Frame
- P. F. Frame, Alberta Environment and Parks, Edmonton, AB, Canada
| | - Mark A. Edwards
- M. A. Edwards, Dept of Renewable Resources, Univ. of Alberta, Edmonton, AB, Canada, and: Royal Alberta Museum, Edmonton, AB, Canada
| | - Delaney D. Frame
- D. D. Frame, Alberta Environment and Parks, Spruce Grove, AB, Canada
| | - Owen M. Slater
- O. M. Slater, Dept of Ecosystem and Public Health, Univ. of Calgary, Calgary, AB, Canada
| | - Andrew E. Derocher
- C. A. Smereka (https://orcid.org/0000-0002-1216-4622) ✉ and A. E Derocher, Dept of Biological Sciences, Univ. of Alberta, Edmonton, AB T6G 2E9, Canada
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17
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Abstract
Abstract
Despite the important role that population density plays in ecological and evolutionary processes, studies of solitary species that occur at low densities remain scarce. In the context of mating systems, density is expected to influence the ability of males to find and monopolize mates, in turn, influencing variance in lifetime mating/reproductive success and the opportunity for selection. Herein, we investigate variance in male lifetime mating success (LMS), lifetime reproductive success (LRS), and the mating system of a sexually dimorphic carnivore that occurs at low densities, the polar bear (Ursus maritimus). Across 17 cohorts, born from 1975 to 1991, male LMS ranged from 0 to10 mates and LRS from 0 to 14 cubs; 40% of known-age males were not known to have reproduced. The opportunity for sexual selection (Is = 1.66, range = 0.60–4.99) and selection (I = 1.76, range: 0.65–4.89) were low compared to species with similar levels of sexual size dimorphism. Skew in male LRS was also low but significant for most cohorts indicating nonrandom reproductive success. Age-specific reproductive success was biased toward males from 11 to 17 years of age, with variation in fecundity (54%) but not longevity (10%) playing an important role in male reproduction. Our results support a growing body of evidence that suggests that male-biased size dimorphism and polygynous mating systems need not be associated with high variance in male mating and/or reproductive success.
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Affiliation(s)
- Evan S Richardson
- Wildlife Research Division, Science and Technology Branch, Environment and Climate Change Canada, Winnipeg, Manitoba, Canada
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
| | - Corey Davis
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
| | - Ian Stirling
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
- Wildlife Research Division, Science and Technology Branch, Environment and Climate Change Canada, University of Alberta, Edmonton, Alberta, Canada
| | - Andrew E Derocher
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
| | - Nicholas J Lunn
- Wildlife Research Division, Science and Technology Branch, Environment and Climate Change Canada, University of Alberta, Edmonton, Alberta, Canada
| | - René M Malenfant
- Department of Biology, University of New Brunswick, Fredericton, New Brunswick, Canada
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18
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Shave JR, Cherry SG, Derocher AE, Fortin D. Seasonal and inter-annual variation in diet for gray wolves Canis lupus in Prince Albert National Park, Saskatchewan. Wildlife Biology 2020. [DOI: 10.2981/wlb.00695] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
Affiliation(s)
- Justin R. Shave
- J. R. Shave ✉ and A. E. Derocher, Dept of Biological Sciences, Univ. of Alberta, Edmonton, AB, T6G 2E9, Canada
| | - Seth G. Cherry
- S. G. Cherry, Parks Canada Agency, Radium Hot Springs, BC, Canada
| | - Andrew E. Derocher
- J. R. Shave ✉ and A. E. Derocher, Dept of Biological Sciences, Univ. of Alberta, Edmonton, AB, T6G 2E9, Canada
| | - Daniel Fortin
- D. Fortin, Dépt de biologie and Centre d'étude de la Foret; Univ. Laval, Québec, QC, Canada
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19
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Boonstra R, Bodner K, Bosson C, Delehanty B, Richardson ES, Lunn NJ, Derocher AE, Molnár PK. The stress of Arctic warming on polar bears. Glob Chang Biol 2020; 26:4197-4214. [PMID: 32364624 DOI: 10.1111/gcb.15142] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Revised: 04/15/2020] [Accepted: 04/23/2020] [Indexed: 05/25/2023]
Abstract
Arctic ecosystems are changing rapidly in response to climate warming. While Arctic mammals are highly evolved to these extreme environments, particularly with respect to their stress axis, some species may have limited capacity to adapt to this change. We examined changes in key components of the stress axis (cortisol and its carrier protein-corticosteroid binding globulin [CBG]) in polar bears (Ursus maritimus) from western Hudson Bay (N = 300) over a 33 year period (1983-2015) during which time the ice-free period was increasing. Changing sea ice phenology limits spring hunting opportunities and extends the period of onshore fasting. We assessed the response of polar bears to a standardized stressor (helicopter pursuit, darting, and immobilization) during their onshore fasting period (late summer-autumn) and quantified the serum levels of the maximum corticosteroid binding capacity (MCBC) of CBG, the serum protein that binds cortisol strongly, and free cortisol (FC). We quantified bear condition (age, sex, female with cubs or not, fat condition), sea ice (breakup in spring-summer, 1 year lagged freeze-up in autumn), and duration of fasting until sample collection as well as cumulative impacts of the latter environmental traits from the previous year. Data were separated into "good" years (1983-1990) when conditions were thought to be optimal and "poor" years (1991-2015) when sea ice conditions deteriorated and fasting on land was extended. MCBC explained 39.4% of the variation in the good years, but only 28.1% in the poor ones, using both biological and environmental variables. MCBC levels decreased with age. Changes in FC were complex, but more poorly explained. Counterintuitively, MCBC levels increased with increased time onshore, 1 year lag effects, and in poor ice years. We conclude that MCBC is a biomarker of stress in polar bears and that the changes we document are a consequence of climate warming.
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Affiliation(s)
- Rudy Boonstra
- Centre for the Neurobiology of Stress, Department of Biological Sciences, University of Toronto Scarborough, Toronto, ON, Canada
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, ON, Canada
| | - Korryn Bodner
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, ON, Canada
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, Canada
| | - Curtis Bosson
- Centre for the Neurobiology of Stress, Department of Biological Sciences, University of Toronto Scarborough, Toronto, ON, Canada
| | - Brendan Delehanty
- Centre for the Neurobiology of Stress, Department of Biological Sciences, University of Toronto Scarborough, Toronto, ON, Canada
| | - Evan S Richardson
- Wildlife Research Division, Science and Technology Branch, Environment and Climate Change Canada, Winnipeg, MB, Canada
| | - Nicholas J Lunn
- Environment and Climate Change Canada, Biological Sciences Building, University of Alberta, Edmonton, AB, Canada
| | - Andrew E Derocher
- Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada
| | - Péter K Molnár
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, ON, Canada
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, Canada
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20
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Lippold A, Aars J, Andersen M, Aubail A, Derocher AE, Dietz R, Eulaers I, Sonne C, Welker JM, Wiig Ø, Routti H. Two Decades of Mercury Concentrations in Barents Sea Polar Bears ( Ursus maritimus) in Relation to Dietary Carbon, Sulfur, and Nitrogen. Environ Sci Technol 2020; 54:7388-7397. [PMID: 32410455 DOI: 10.1021/acs.est.0c01848] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Temporal trends of total mercury (THg) were examined in female polar bear (Ursus maritimus) hair (n = 199) from the Barents Sea in 1995-2016. In addition, hair values of stable isotopes (n = 190-197) of carbon (δ13C), sulfur (δ34S), and nitrogen (δ15N) and information on breeding status, body condition, and age were obtained. Stable isotope values of carbon and sulfur reflect dietary source (e.g., marine vs terrestrial) and the nitrogen trophic level. Values for δ13C and δ34S declined by -1.62 and -1.18‰ over the time of the study period, respectively, while values for δ15N showed no trend. Total Hg concentrations were positively related to both δ13C and δ34S. Yearly median THg concentrations ranged from 1.61 to 2.75 μg/g and increased nonlinearly by 0.86 μg/g in total over the study. Correcting THg concentrations for stable isotope values of carbon and sulfur and additionally breeding status and age slightly accelerated the increase in THg concentrations; however, confidence intervals of the raw THg trend and the corrected THg trend had substantial overlap. The rise in THg concentrations in the polar bear food web was possibly related to climate-related re-emissions of previously stored Hg from thawing sea-ice, glaciers, and permafrost.
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Affiliation(s)
- Anna Lippold
- Fram Centre, Norwegian Polar Institute, Tromsø 9296, Norway
| | - Jon Aars
- Fram Centre, Norwegian Polar Institute, Tromsø 9296, Norway
| | | | - Aurore Aubail
- Littoral, Environment and Societies (CNRS/La Rochelle University), La Rochelle 17000, France
| | - Andrew E Derocher
- Department of Biological Sciences, University of Alberta, Edmonton T6G 2E9, Canada
| | - Rune Dietz
- Institute of Bioscience, Arctic Research Centre, Aarhus University, Roskilde 4000, Denmark
| | - Igor Eulaers
- Institute of Bioscience, Arctic Research Centre, Aarhus University, Roskilde 4000, Denmark
| | - Christian Sonne
- Institute of Bioscience, Arctic Research Centre, Aarhus University, Roskilde 4000, Denmark
| | - Jeffrey M Welker
- University of Alaska Anchorage, Anchorage 99508, United States
- University of Oulu, Oulu 90014, Finland
- University of the Arctic, Rovaniemi 96460, Finland
| | - Øystein Wiig
- Fram Centre, Norwegian Polar Institute, Tromsø 9296, Norway
- Natural History Museum, University of Oslo, 0318 Oslo, Norway
| | - Heli Routti
- Fram Centre, Norwegian Polar Institute, Tromsø 9296, Norway
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21
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Biddlecombe BA, Bayne EM, Lunn NJ, McGeachy D, Derocher AE. Comparing sea ice habitat fragmentation metrics using integrated step selection analysis. Ecol Evol 2020; 10:4791-4800. [PMID: 32551061 PMCID: PMC7297736 DOI: 10.1002/ece3.6233] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Revised: 02/21/2020] [Accepted: 03/10/2020] [Indexed: 11/06/2022] Open
Abstract
Habitat fragmentation occurs when continuous habitat gets broken up as a result of ecosystem change. While commonly studied in terrestrial ecosystems, Arctic sea ice ecosystems also experience fragmentation, but are rarely studied in this context. Most fragmentation analyses are conducted using patch-based metrics, which are potentially less suitable for sea ice that has gradual changes between sea ice cover, than distinct "long-term" patches. Using an integrated step selection analysis, we compared the descriptive power of a patch-based metric to a more novel metric, the variation in local spatial autocorrelation over time. We used satellite telemetry data from 39 adult female polar bears (Ursus maritimus) in Hudson Bay to examine their sea ice habitat using Advanced Microwave Scanning Radiometer 2 data during sea ice breakup in May through July from 2013-2018. Spatial autocorrelation resulted in better model fits across 64% of individuals, although both metrics were more effective in describing movement patterns than habitat selection. Variation in local spatial autocorrelation allows for the visualization of sea ice habitat at complex spatial and temporal scales, condensing a targeted time period of habitat that would otherwise have to be analyzed daily.
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Affiliation(s)
| | - Erin M. Bayne
- Department of Biological SciencesUniversity of AlbertaEdmontonAlbertaCanada
| | - Nicholas J. Lunn
- Wildlife Research Division, Science and Technology BranchEnvironment and Climate Change CanadaEdmontonABCanada
| | - David McGeachy
- Wildlife Research Division, Science and Technology BranchEnvironment and Climate Change CanadaEdmontonABCanada
| | - Andrew E. Derocher
- Department of Biological SciencesUniversity of AlbertaEdmontonAlbertaCanada
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22
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Boucher NP, Derocher AE, Richardson ES. Spatial and temporal variability in ringed seal ( Pusa hispida) stable isotopes in the Beaufort Sea. Ecol Evol 2020; 10:4178-4192. [PMID: 32489588 PMCID: PMC7246210 DOI: 10.1002/ece3.6186] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Revised: 02/14/2020] [Accepted: 02/17/2020] [Indexed: 12/02/2022] Open
Abstract
Arctic ecosystem dynamics are shifting in response to warming temperatures and sea ice loss. Such ecosystems may be monitored by examining the diet of upper trophic level species, which varies with prey availability. To assess interannual variation in the Beaufort Sea ecosystem, we examined spatial and temporal trends in ringed seal (Pusa hispida) δ13C and δ15N in claw growth layers grown from 1964 to 2011. Stable isotopes were correlated with climate indices, environmental conditions, seal population productivity, and geographic location. Sex and age did not influence stable isotopes. Enriched 13C was linked to cyclonic circulation regimes, seal productivity, and westward sampling locations. Higher δ15N was linked to lower sea surface temperatures, a higher percentage of pups in the subsistence harvest, and sample locations that were eastward and further from shore. From the 1960s to 2000s, ringed seal niche width expanded, suggesting a diversification of diet due to expansion of prey and/or seal space use. Overall, trends in ringed seal stable isotopes indicate changes within the Beaufort Sea ecosystem affected by water temperatures and circulation regimes. We suggest that continued monitoring of upper trophic level species will yield insights into changing ecosystem structure with climate change.
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Affiliation(s)
- Nicole P. Boucher
- Department of Biological SciencesUniversity of AlbertaEdmontonABCanada
| | | | - Evan S. Richardson
- Wildlife Research Division, Science and Technology BranchEnvironment and Climate Change CanadaWinnipegMBCanada
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23
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Florko KRN, Derocher AE, Breiter CJC, Ghazal M, Hedman D, Higdon JW, Richardson ES, Sahanatien V, Trim V, Petersen SD. Polar bear denning distribution in the Canadian Arctic. Polar Biol 2020. [DOI: 10.1007/s00300-020-02657-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
AbstractDeclines in Arctic sea ice associated with climate change have resulted in habitat loss for ice-adapted species, while facilitating increased human development at higher latitudes. Development increases land-use and shipping traffic, which can threaten ecologically and culturally important species. Female polar bears (Ursus maritimus) and cubs are susceptible to disturbance during denning; a better understanding of denning habitat distribution may aid management. We compiled existing location data on polar bear denning (n = 64 sources) in Canada between 1967 and 2018, including traditional ecological knowledge (TEK) studies, government and consultant reports, peer-reviewed scientific articles, and unpublished data acquired through data-sharing agreements. We synthesized these data to create a map of known denning locations. Most coastal regions in northern Canada supported denning, but large areas exist where denning is unreported. Gaps remain in the knowledge of polar bear denning in Canada and filling these will aid the conservation and management of polar bears in a changing Arctic.
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24
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Yurkowski DJ, Richardson ES, Lunn NJ, Muir DCG, Johnson AC, Derocher AE, Ehrman AD, Houde M, Young BG, Debets CD, Sciullo L, Thiemann GW, Ferguson SH. Contrasting Temporal Patterns of Mercury, Niche Dynamics, and Body Fat Indices of Polar Bears and Ringed Seals in a Melting Icescape. Environ Sci Technol 2020; 54:2780-2789. [PMID: 32046488 DOI: 10.1021/acs.est.9b06656] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Polar bears (Ursus maritimus) and ringed seals (Pusa hispida) have a strong predator-prey relationship and are facing climate-associated Arctic habitat loss and harmful dietary exposure to total mercury (THg) and other pollutants. However, little is known about whether both species inhabiting the same area exhibit similar temporal patterns in Hg concentration, niche dynamics, and body fat indices. We used THg, δ13C, and δ15N values of western Hudson Bay polar bear hair (2004-2016) and ringed seal muscle samples (2003-2015) to investigate temporal trends of these variables and multidimensional niche metrics, as well as body fat indices for both species. We found a decline in THg concentration (by 3.8% per year) and δ13C (by 1.5‰) in ringed seals suggesting a change in feeding habits and carbon source use over time, whereas no significant changes occurred in polar bears. In contrast, the polar bear 3-dimensional niche size decreased by nearly half with no change in ringed seal niche size. The δ13C spacing between both species increased by approximately 1.5× suggesting different responses to annual changes in sympagic-pelagic carbon source production. Ringed seal body fat index was higher in years of earlier sea ice breakup with no change occurring in polar bears. These findings indicate that both species are responding differently to a changing environment suggesting a possible weakening of their predator-prey relationship in western Hudson Bay.
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Affiliation(s)
- David J Yurkowski
- University of Manitoba, Winnipeg, Manitoba MB R3T 2N2, Canada
- Fisheries and Oceans Canada, Winnipeg, Manitoba MB R3T 2N6, Canada
| | - Evan S Richardson
- Environment and Climate Change Canada, Winnipeg, Manitoba MB R3B 2B4, Canada
| | - Nicholas J Lunn
- Environment and Climate Change Canada, Edmonton, Alberta AB T5J 0J4, Canada
| | - Derek C G Muir
- Environment and Climate Change Canada, Burlington, Ontario ON L7S 1A1, Canada
| | - Amy C Johnson
- University of Alberta, Edmonton, Alberta AB T6G 2R3, Canada
| | | | - Ashley D Ehrman
- Fisheries and Oceans Canada, Winnipeg, Manitoba MB R3T 2N6, Canada
| | - Magali Houde
- Environment and Climate Change Canada, Montreal, Quebec QC H2Y 2E7, Canada
| | - Brent G Young
- Fisheries and Oceans Canada, Winnipeg, Manitoba MB R3T 2N6, Canada
| | | | - Luana Sciullo
- York University, Toronto, Ontario ON M3J 1P3, Canada
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25
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Folio DM, Aars J, Gimenez O, Derocher AE, Wiig Ø, Cubaynes S. How many cubs can a mum nurse? Maternal age and size influence litter size in polar bears. Biol Lett 2019; 15:20190070. [PMID: 31039729 DOI: 10.1098/rsbl.2019.0070] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Life-history theory predicts that females' age and size affect the level of maternal investment in current reproduction, balanced against the future reproductive effort, maintenance and survival. Using long-term (30 years) individual data on 193 female polar bears ( Ursus maritimus), we assessed age- and size-specific variation on litter size. Litter size varied with maternal age, younger females had higher chances of losing a cub during their first months of life. Results suggest an improvement in reproductive abilities early in life due to experience with subsequent reproductive senescence. Litter size increased with maternal size, indicating that size may reflect individual quality. We also found an optimum in the probability of having twins, suggesting stabilizing selection on female body size. Heterogeneity was observed among the largest females, suggesting that large size comes at a cost.
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Affiliation(s)
- Dorinda Marie Folio
- 1 CEFE, CNRS, Univ Montpellier , Univ Paul Valéry Montpellier 3, EPHE, IRD, Montpellier , France
| | - Jon Aars
- 2 Norwegian Polar Institute, Fram Centre , Tromsø , Norway
| | - Olivier Gimenez
- 1 CEFE, CNRS, Univ Montpellier , Univ Paul Valéry Montpellier 3, EPHE, IRD, Montpellier , France
| | - Andrew E Derocher
- 3 Department of Biological Sciences, University of Alberta , Edmonton , Canada
| | - Øystein Wiig
- 4 Natural History Museum, University of Oslo , Oslo , Norway
| | - Sarah Cubaynes
- 1 CEFE, CNRS, Univ Montpellier , Univ Paul Valéry Montpellier 3, EPHE, IRD, Montpellier , France.,5 MMDN, INSERM U1198, EPHE/PSL and University of Montpellier , France
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26
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Bechshoft T, Dyck M, St Pierre KA, Derocher AE, St Louis V. The use of hair as a proxy for total and methylmercury burdens in polar bear muscle tissue. Sci Total Environ 2019; 686:1120-1128. [PMID: 31412508 DOI: 10.1016/j.scitotenv.2019.06.087] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Revised: 06/05/2019] [Accepted: 06/05/2019] [Indexed: 06/10/2023]
Abstract
Polar bears (Ursus maritimus) are an ecologically important species in the Arctic, whose health, and that of the people whose livelihoods depend on them, are increasingly affected by climate change and the bioaccumulation of contaminants such as mercury (Hg). Although methylmercury (MeHg) is the toxic form of Hg that biomagnifies up food webs, risk assessment studies typically only report on total Hg (THg) concentrations because it is cheaper to quantify. Furthermore, hair is commonly analysed for THg in polar bear as well as human risk assessment studies because it is relatively non-invasive to collect, yet we know little of how THg and MeHg concentrations differ between hair and muscle tissues. In this study, we quantified THg and MeHg concentrations in hair and muscle from 44 polar bears (24 sub-adults: 9 females, 15 males; 18 adults: 5 females, 13 males, and 2 males of unknown age group), harvested in 2015 and 2016 from four subpopulations in Nunavut, Canada (Davis Strait, n = 3; Gulf of Boothia, n = 8; Baffin Bay, n = 15; Foxe Basin, n = 18). We found only moderately positive correlations (0.4 ≤ r ≤ 0.5) between THg concentrations in hair and THg and MeHg concentrations in muscle. Further, 75% and 88% of THg was MeHg in hair and muscle, respectively. High concentrations of THg in hair - 71% of the samples were above the suggested neurochemical no observed effect level for polar bears - suggest some of the bears may be adversely affected by Hg-related health effects. Despite this, all MeHg concentrations in muscle (0.1 to 0.4 mg/kg (wet weight, ww)) were below the consumption maximum Hg concentration of 0.5 mg/kg (ww) set by Canadian health authorities.
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Affiliation(s)
- Thea Bechshoft
- University of Alberta, Department of Biological Sciences, Edmonton, Alberta T6G 2E9, Canada.
| | - Markus Dyck
- Department of Environment, Government of Nunavut, Igloolik, Nunavut X0A 0H0, Canada.
| | - Kyra A St Pierre
- University of Alberta, Department of Biological Sciences, Edmonton, Alberta T6G 2E9, Canada.
| | - Andrew E Derocher
- University of Alberta, Department of Biological Sciences, Edmonton, Alberta T6G 2E9, Canada.
| | - Vincent St Louis
- University of Alberta, Department of Biological Sciences, Edmonton, Alberta T6G 2E9, Canada.
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27
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Reimer JR, Mangel M, Derocher AE, Lewis MA. Modeling optimal responses and fitness consequences in a changing Arctic. Glob Chang Biol 2019; 25:3450-3461. [PMID: 31077520 DOI: 10.1111/gcb.14681] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2019] [Accepted: 04/29/2019] [Indexed: 06/09/2023]
Abstract
Animals must balance a series of costs and benefits while trying to maximize their fitness. For example, an individual may need to choose how much energy to allocate to reproduction versus growth, or how much time to spend on vigilance versus foraging. Their decisions depend on complex interactions between environmental conditions, behavioral plasticity, reproductive biology, and energetic demands. As animals respond to novel environmental conditions caused by climate change, the optimal decisions may shift. Stochastic dynamic programming provides a flexible modeling framework with which to explore these trade-offs, but this method has not yet been used to study possible changes in optimal trade-offs caused by climate change. We created a stochastic dynamic programming model capturing trade-off decisions required by an individual adult female polar bear (Ursus maritimus) as well as the fitness consequences of her decisions. We predicted optimal foraging decisions throughout her lifetime as well as the energetic thresholds below which it is optimal for her to abandon a reproductive attempt. To explore the effects of climate change, we shortened the spring feeding period by up to 3 weeks, which led to predictions of riskier foraging behavior and higher reproductive thresholds. The resulting changes in fitness may be interpreted as a best-case scenario, where bears adapt instantaneously and optimally to new environmental conditions. If the spring feeding period was reduced by 1 week, her expected fitness declined by 15%, and if reduced by 3 weeks, expected fitness declined by 68%. This demonstrates an effective way to explore a species' optimal response to a changing landscape of costs and benefits and highlights the fact that small annual effects can result in large cumulative changes in expected lifetime fitness.
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Affiliation(s)
- Jody R Reimer
- Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada
- Department of Mathematical and Statistical Sciences, University of Alberta, Edmonton, AB, Canada
| | - Marc Mangel
- Institute of Marine Sciences and Department of Applied Mathematics and Statistics, University of California, Santa Cruz, Santa Cruz, California
- Department of Biology, University of Bergen, Bergen, Norway
| | - Andrew E Derocher
- 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
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28
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Affiliation(s)
- Jody R. Reimer
- Department of Biological Sciences University of Alberta Edmonton AB Canada
- Department of Mathematical and Statistical Sciences University of Alberta Edmonton AB Canada
| | - Marc Mangel
- Department of Biology University of Bergen Bergen Norway
- Institute of Marine Sciences and Department of Applied Mathematics University of California Santa Cruz CA USA
| | - Andrew E. Derocher
- 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
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29
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Shave JR, Derocher AE, Cherry SG, Thiemann GW. Chronic stress and body condition of wolf-killed prey in Prince Albert National Park, Saskatchewan. Conserv Physiol 2019; 7:coz037. [PMID: 31308948 PMCID: PMC6618025 DOI: 10.1093/conphys/coz037] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Revised: 05/02/2019] [Accepted: 05/23/2019] [Indexed: 05/30/2023]
Abstract
Chronic stress and poor body condition can cause adverse physiological and behavioural responses and may make animals more vulnerable to predation. We examined hair cortisol concentration (HCC) and marrow lipid content, as bioindicators of chronic stress and body condition, respectively, of bison (Bison bison bison), moose (Alces alces) and white-tailed deer (Odocoileus virginianus) killed by wolves (Canis lupus) in Prince Albert National Park (PANP), Saskatchewan, Canada. The Sturgeon River plains bison population in PANP is one of only a few wild populations of plains bison in their historical range in Canada and has experienced a decline of around 50% since 2005. We expected wolf-killed bison to have elevated HCC compared to human-harvested bison and that there would be a negative relationship between HCC and marrow lipids among wolf-killed animals. We compared HCC between different mortality sources for bison (wolf-killed n = 20 or human-harvested n = 23) and found that HCC was significantly elevated in wolf-killed bison (¯ = 7.56 ± 1.35 pg/mg). We found that HCC, species, sex and snow depth were all significant predictor variables of marrow lipid content of bison (n = 14), moose (n = 11) and deer (n = 27). Bison displayed the strongest negative correlation between HCC and marrow lipid content (r2 = 0.31). Our results suggest that chronic stress and poor body condition make prey more vulnerable to predation by wolves. HCC and marrow lipid content can provide reliable indicators of the physiological response of animals to stressors and may provide information on expected predator success that can be used to predict predator population dynamics.
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Affiliation(s)
- Justin R Shave
- Department of Biological Sciences, University of Alberta, Edmonton, Canada
| | - Andrew E Derocher
- Department of Biological Sciences, University of Alberta, Edmonton, Canada
| | | | - Gregory W Thiemann
- Faculty of Environmental Studies, York University, Toronto, Ontario, Canada
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30
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Abstract
The abundance of ungulate populations may fluctuate in response to several limiting factors, including climate, diseases, and predation. In the northern Richardson Mountains, Canada, Dall sheep (Ovis dalli dalli) have undergone a major decline in the past decades and predation by grizzly bears (Ursus arctos) and wolves (Canis lupus) was suspected as a leading cause. To better understand the relationship between these three species located in this rugged and remote ecosystem, we relied on a combination of indirect methods. We investigated the apparent role of predation on the Dall sheep population using spatial ecology and stable isotopes. We examined seasonal variation in predation risk, focusing on how it may affect Dall sheep habitat use and sexual segregation, and we evaluated the proportion of Dall sheep in the diet of both predators using stable isotopes. The movements of the three species were monitored by satellite telemetry. Dall sheep habitat use patterns were analyzed using topographical features, greenness index, land cover, and apparent predation risk. The diets of grizzly bears and wolves were examined using a Bayesian mixing model for carbon and nitrogen stable isotopes. We found that Dall sheep habitat use varied seasonally, with different patterns for ewes and rams. Exposure to grizzly bear risk was higher for rams during summer, while ewes were further exposed to wolf apparent predation risk during winter. The importance of safe habitats for ewes was reflected in space use patterns. Stable isotopes analyses suggested that the diet of grizzly bears was largely from animal sources, with mountain mammals comprising about one quarter. Wolves mostly fed on both aquatic browsers and mountain mammals. Diet variation between individual predators suggested that some individuals specialized on mountain mammals, likely including Dall sheep. We conclude that grizzly bear and wolf apparent predation risk are important in driving Dall sheep habitat use and play a role in sexual segregation. Overall, this study presents an innovative combination of indirect methods that could be applied elsewhere to better understand predator-prey dynamics in remote ecosystems.
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Affiliation(s)
- Catherine Lambert Koizumi
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
- Gwich’in Renewable Resources Board, Inuvik, Northwest Territories, Canada
| | - Andrew E. Derocher
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
- * E-mail:
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31
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Reimer JR, Caswell H, Derocher AE, Lewis MA. Ringed seal demography in a changing climate. Ecol Appl 2019; 29:e01855. [PMID: 30672632 DOI: 10.1002/eap.1855] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Revised: 10/09/2018] [Accepted: 11/13/2018] [Indexed: 06/09/2023]
Abstract
Climate change is affecting species' distributions and abundances worldwide. Baseline population estimates, against which future observations may be compared, are necessary if we are to detect ecological change. Arctic sea ice ecosystems are changing rapidly and we lack baseline population estimates for many ice-associated species. Provided we can detect them, changes in Arctic marine ecosystems may be signaled by changes in indicator species such as ringed seals (Pusa hispida). Ringed seal monitoring has provided estimates of survival and fertility rates, but these have not been used for population-level inference. Using matrix population models, we synthesized existing demographic parameters to obtain estimates of historical ringed seal population growth and structure in Amundsen Gulf and Prince Albert Sound, Canada. We then formalized existing hypotheses about the effects of emerging environmental stressors (i.e., earlier spring ice breakup and reduced snow depth) on ringed seal pup survival. Coupling the demographic model to ice and snow forecasts available from the Coupled Model Intercomparison Project resulted in projections of ringed seal population size and structure up to the year 2100. These projections showed median declines in population size ranging from 50% to 99%. Corresponding to these projected declines were substantial changes in population structure, with increasing proportions of ringed seal pups and adults and declining proportions of juveniles. We explored if currently collected, harvest-based data could be used to detect the projected changes in population stage structure. Our model suggests that at a present sample size of 100 seals per year, the projected changes in stage structure would only be reliably detected by mid-century, even for the most extreme climate models. This modeling process revealed inconsistencies in existing estimates of ringed seal demographic rates. Mathematical population models such as these can contribute both to understanding past population trends as well as predicting future ones, both of which are necessary if we are to detect and interpret future observations.
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Affiliation(s)
- Jody R Reimer
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta , T6G 2E9, Canada
- Department of Mathematical and Statistical Sciences, University of Alberta, Edmonton, Alberta, T6G 2G1, Canada
| | - Hal Caswell
- Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Amsterdam, 1090, The Netherlands
| | - Andrew E Derocher
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta , T6G 2E9, Canada
| | - Mark A Lewis
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta , T6G 2E9, Canada
- Department of Mathematical and Statistical Sciences, University of Alberta, Edmonton, Alberta, T6G 2G1, Canada
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32
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Lippold A, Bourgeon S, Aars J, Andersen M, Polder A, Lyche JL, Bytingsvik J, Jenssen BM, Derocher AE, Welker JM, Routti H. Temporal Trends of Persistent Organic Pollutants in Barents Sea Polar Bears ( Ursus maritimus) in Relation to Changes in Feeding Habits and Body Condition. Environ Sci Technol 2019; 53:984-995. [PMID: 30548071 DOI: 10.1021/acs.est.8b05416] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Temporal trends of persistent organic pollutants (POPs: PCBs, OH-PCBs, p, p'-DDE, HCB, β-HCH, oxychlordane, BDE-47, and 153) in relation to changes in feeding habits and body condition in adult female polar bears ( Ursus maritimus) from the Barents Sea subpopulation were examined over 20 years (1997-2017). All 306 samples were collected in the spring (April). Both stable isotope values of nitrogen (δ15N) and carbon (δ13C) from red blood cells declined over time, with a steeper trend for δ13C between 2012 and 2017, indicating a decreasing intake of marine and high trophic level prey items. Body condition, based on morphometric measurements, had a nonsignificant decreasing tendency between 1997 and 2005, and increased significantly between 2005 and 2017. Plasma concentrations of BDE-153 and β-HCH did not significantly change over time, whereas concentrations of Σ4PCB, Σ5OH-PCB, BDE-47, and oxychlordane declined linearly. Concentrations of p, p'-DDE and HCB, however, declined until 2012 and 2009, respectively, and increased thereafter. Changes in feeding habits and body condition did not significantly affect POP trends. The study indicates that changes in diet and body condition were not the primary driver of POPs in polar bears, but were controlled in large part by primary and/or secondary emissions of POPs.
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Affiliation(s)
- Anna Lippold
- Norwegian Polar Institute , Tromsø 9296 , Norway
- The Arctic University of Norway (UiT) , Tromsø 9019 , Norway
| | - Sophie Bourgeon
- The Arctic University of Norway (UiT) , Tromsø 9019 , Norway
| | - Jon Aars
- Norwegian Polar Institute , Tromsø 9296 , Norway
| | | | - Anuschka Polder
- Norwegian University of Life Sciences (NMBU) , Oslo 0454 , Norway
| | - Jan Ludvig Lyche
- Norwegian University of Life Sciences (NMBU) , Oslo 0454 , Norway
| | - Jenny Bytingsvik
- Akvaplan-niva AS , Tromsø 9296 , Norway
- Norwegian University of Science and Technology (NTNU) Trondheim 7491 , Norway
| | - Bjørn Munro Jenssen
- Norwegian University of Science and Technology (NTNU) Trondheim 7491 , Norway
| | | | - Jeffrey M Welker
- University of Alaska Anchorage (UAA) , Anchorage 99508 , United States
- University of Oulu , Oulu 90014 , Finland
- University of the Arctic
| | - Heli Routti
- Norwegian Polar Institute , Tromsø 9296 , Norway
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33
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Yurkowski DJ, Auger-Méthé M, Mallory ML, Wong SNP, Gilchrist G, Derocher AE, Richardson E, Lunn NJ, Hussey NE, Marcoux M, Togunov RR, Fisk AT, Harwood LA, Dietz R, Rosing-Asvid A, Born EW, Mosbech A, Fort J, Grémillet D, Loseto L, Richard PR, Iacozza J, Jean-Gagnon F, Brown TM, Westdal KH, Orr J, LeBlanc B, Hedges KJ, Treble MA, Kessel ST, Blanchfield PJ, Davis S, Maftei M, Spencer N, McFarlane-Tranquilla L, Montevecchi WA, Bartzen B, Dickson L, Anderson C, Ferguson SH. Abundance and species diversity hotspots of tracked marine predators across the North American Arctic. DIVERS DISTRIB 2018. [DOI: 10.1111/ddi.12860] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Affiliation(s)
| | | | | | | | - Grant Gilchrist
- Environment and Climate Change Canada; Ottawa Ontario Canada
| | | | - Evan Richardson
- Environment and Climate Change Canada; Winnipeg Manitoba Canada
| | | | | | | | - Ron R. Togunov
- University of British Columbia; Vancouver British Columbia Canada
| | | | - Lois A. Harwood
- Fisheries and Oceans Canada; Yellowknife Northwest Territories Canada
| | | | | | - Erik W. Born
- Greenland Institute of Natural Resources; Nuuk Greenland
| | | | - Jérôme Fort
- Littoral, Environnement et Sociétés (LIENSs); UMR7266 CNRS-University of La Rochelle; La Rochelle France
| | - David Grémillet
- Centre d’Ecologie Fonctionnelle et Evolutive; UMR 5175, CNRS; Montpellier France
| | - Lisa Loseto
- Fisheries and Oceans Canada; Winnipeg Manitoba Canada
| | | | - John Iacozza
- University of Manitoba; Winnipeg Manitoba Canada
| | | | | | | | - Jack Orr
- Fisheries and Oceans Canada; Winnipeg Manitoba Canada
| | | | | | | | - Steven T. Kessel
- Daniel P. Haerther Center for Conservation and Research; John G. Shedd Aquarium; Chicago Illinois
| | | | - Shanti Davis
- High Arctic Gull Research Group; Victoria British Columbia Canada
| | - Mark Maftei
- High Arctic Gull Research Group; Victoria British Columbia Canada
| | - Nora Spencer
- High Arctic Gull Research Group; Victoria British Columbia Canada
| | | | | | - Blake Bartzen
- Environment and Climate Change Canada; Saskatoon Saskatchewan Canada
| | - Lynne Dickson
- Environment and Climate Change Canada; Edmonton Alberta Canada
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Liu Y, Richardson ES, Derocher AE, Lunn NJ, Lehmler HJ, Li X, Zhang Y, Cui JY, Cheng L, Martin JW. Hundreds of Unrecognized Halogenated Contaminants Discovered in Polar Bear Serum. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201809906] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Yanna Liu
- Division of Analytical and Environmental Toxicology; Department of Laboratory Medicine and Pathology; University of Alberta; Edmonton Alberta T6G 2G3 Canada
| | - Evan S. Richardson
- Wildlife Research Division, Science and Technology Branch; Environment and Climate Change Canada; Government of Canada; Winnipeg Manitoba R3C 4W2 Canada
| | - Andrew E. Derocher
- Department of Biological Sciences; University of Alberta; Edmonton Alberta T6G 2E9 Canada
| | - Nicholas J. Lunn
- Wildlife Research Division, Science and Technology Branch; Environment and Climate Change Canada; Edmonton Alberta T6G 2E9 Canada
| | - Hans-Joachim Lehmler
- Department of Occupational and Environmental Health; College of Public Health; University of Iowa; Iowa City IA 52242-5000 USA
| | - Xueshu Li
- Department of Occupational and Environmental Health; College of Public Health; University of Iowa; Iowa City IA 52242-5000 USA
| | - Yifeng Zhang
- Division of Analytical and Environmental Toxicology; Department of Laboratory Medicine and Pathology; University of Alberta; Edmonton Alberta T6G 2G3 Canada
| | - Julia Yue Cui
- Department of Environmental & Occupational Health Sciences; University of Washington; Seattle WA 98105-6099 USA
| | - Lihua Cheng
- Department of Environmental & Occupational Health Sciences; University of Washington; Seattle WA 98105-6099 USA
| | - Jonathan W. Martin
- Division of Analytical and Environmental Toxicology; Department of Laboratory Medicine and Pathology; University of Alberta; Edmonton Alberta T6G 2G3 Canada
- Science for Life Laboratory; Department of Environmental Science and Analytical Chemistry; Stockholm University; 10691 Stockholm Sweden
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Liu Y, Richardson ES, Derocher AE, Lunn NJ, Lehmler HJ, Li X, Zhang Y, Cui JY, Cheng L, Martin JW. Hundreds of Unrecognized Halogenated Contaminants Discovered in Polar Bear Serum. Angew Chem Int Ed Engl 2018; 57:16401-16406. [PMID: 30376612 DOI: 10.1002/anie.201809906] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Revised: 10/11/2018] [Indexed: 11/06/2022]
Abstract
Exposure of polar bears (Ursus maritimus) to persistent organic pollutants was discovered in the 1970s, but recent evidence suggests the presence of unknown toxic chemicals in their blood. Protein and phospholipid depleted serum was stirred with polyethersulfone capillaries to extract a broad range of analytes, and nontarget mass spectrometry with "fragmentation flagging" was used for detection. Hundreds of analytes were discovered belonging to 13 classes, including novel polychlorinated biphenyl (PCB) metabolites and many fluorinated or chlorinated substances not previously detected. All analytes were detected in the oldest (mid-1980s) archived polar bear serum from Hudson Bay and Beaufort Sea, and all fluorinated classes showed increasing trends. A mouse experiment confirmed the novel PCB metabolites, suggesting that these could be widespread in mammals. Historical exposure and toxic risk has been underestimated, and these halogenated contaminants pose uncertain risks to this threatened species.
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Affiliation(s)
- Yanna Liu
- Division of Analytical and Environmental Toxicology, Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, Alberta, T6G 2G3, Canada
| | - Evan S Richardson
- Wildlife Research Division, Science and Technology Branch, Environment and Climate Change Canada, Government of Canada, Winnipeg, Manitoba, R3C 4W2, Canada
| | - Andrew E Derocher
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, T6G 2E9, Canada
| | - Nicholas J Lunn
- Wildlife Research Division, Science and Technology Branch, Environment and Climate Change Canada, Edmonton, Alberta, T6G 2E9, Canada
| | - Hans-Joachim Lehmler
- Department of Occupational and Environmental Health, College of Public Health, University of Iowa, Iowa City, IA, 52242-5000, USA
| | - Xueshu Li
- Department of Occupational and Environmental Health, College of Public Health, University of Iowa, Iowa City, IA, 52242-5000, USA
| | - Yifeng Zhang
- Division of Analytical and Environmental Toxicology, Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, Alberta, T6G 2G3, Canada
| | - Julia Yue Cui
- Department of Environmental & Occupational Health Sciences, University of Washington, Seattle, WA, 98105-6099, USA
| | - Lihua Cheng
- Department of Environmental & Occupational Health Sciences, University of Washington, Seattle, WA, 98105-6099, USA
| | - Jonathan W Martin
- Division of Analytical and Environmental Toxicology, Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, Alberta, T6G 2G3, Canada.,Science for Life Laboratory, Department of Environmental Science and Analytical Chemistry, Stockholm University, 10691, Stockholm, Sweden
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O'Donovan SA, Budge SM, Hobson KA, Kelly AP, Derocher AE. Intrapopulation variability in wolf diet revealed using a combined stable isotope and fatty acid approach. Ecosphere 2018. [DOI: 10.1002/ecs2.2420] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Affiliation(s)
- Sean A. O'Donovan
- Department of Biological Sciences; University of Alberta; Edmonton Alberta T6G 2E9 Canada
| | - Suzanne M. Budge
- Department of Process Engineering and Applied Science; Dalhousie University; Halifax Nova Scotia B3H 4R2 Canada
| | - Keith A. Hobson
- Department of Biology; University of Western Ontario; London Ontario N6A 5B7 Canada
| | - Allicia P. Kelly
- Environment and Natural Resources; Government of Northwest Territories; Fort Smith Northwest Territories X0E 0P0 Canada
| | - Andrew E. Derocher
- Department of Biological Sciences; University of Alberta; Edmonton Alberta T6G 2E9 Canada
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Viengkone M, Derocher AE, Richardson ES, Obbard ME, Dyck MG, Lunn NJ, Sahanatien V, Robinson BG, Davis CS. Assessing spatial discreteness of Hudson Bay polar bear populations using telemetry and genetics. Ecosphere 2018. [DOI: 10.1002/ecs2.2364] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Affiliation(s)
- Michelle Viengkone
- Department of Biological Sciences; University of Alberta; Edmonton Alberta T6G 2E9 Canada
| | - Andrew E. Derocher
- Department of Biological Sciences; University of Alberta; Edmonton Alberta T6G 2E9 Canada
| | - Evan S. Richardson
- Wildlife Research Division, Science and Technology Branch; Environment and Climate Change Canada; Biological Sciences Building; University of Alberta; Edmonton Alberta T6G 2E9 Canada
| | - Martyn E. Obbard
- Wildlife Research and Monitoring Section; Ontario Ministry of Natural Resources and Forestry; Trent University; Peterborough Ontario K9J 7B8 Canada
| | - Markus G. Dyck
- Department of Environment; Government of Nunavut; Igloolik Nunavut X0A 0L0 Canada
| | - Nicholas J. Lunn
- Wildlife Research Division, Science and Technology Branch; Environment and Climate Change Canada; Biological Sciences Building; University of Alberta; Edmonton Alberta T6G 2E9 Canada
| | - Vicki Sahanatien
- Department of Biological Sciences; University of Alberta; Edmonton Alberta T6G 2E9 Canada
| | - Barry G. Robinson
- Department of Biological Sciences; University of Alberta; Edmonton Alberta T6G 2E9 Canada
| | - Corey S. Davis
- Department of Biological Sciences; University of Alberta; Edmonton Alberta T6G 2E9 Canada
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Tartu S, Aars J, Andersen M, Polder A, Bourgeon S, Merkel B, Lowther AD, Bytingsvik J, Welker JM, Derocher AE, Jenssen BM, Routti H. Choose Your Poison-Space-Use Strategy Influences Pollutant Exposure in Barents Sea Polar Bears. Environ Sci Technol 2018; 52:3211-3221. [PMID: 29363970 DOI: 10.1021/acs.est.7b06137] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Variation in space-use is common within mammal populations. In polar bears, Ursus maritimus, some individuals follow the sea ice (offshore bears) whereas others remain nearshore yearlong (coastal bears). We studied pollutant exposure in relation to space-use patterns (offshore vs coastal) in adult female polar bears from the Barents Sea equipped with satellite collars (2000-2014, n = 152). First, we examined the differences in home range (HR) size and position, body condition, and diet proxies (nitrogen and carbon stable isotopes, n = 116) between offshore and coastal space-use. Second, we investigated how HR, space-use, body condition, and diet were related to plasma concentrations of polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs) ( n = 113), perfluoroalkyl substances (PFASs; n = 92), and hydroxylated-PCBs ( n = 109). Offshore females were in better condition and had a more specialized diet than did coastal females. PCBs, OCPs, and hydroxylated-PCB concentrations were not related to space-use strategy, yet PCB concentrations increased with increasing latitude, and hydroxylated-PCB concentrations were positively related to HR size. PFAS concentrations were 30-35% higher in offshore bears compared to coastal bears and also increased eastward. On the basis of the results we conclude that space-use of Barents Sea female polar bears influences their pollutant exposure, in particular plasma concentrations of PFAS.
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Affiliation(s)
- Sabrina Tartu
- Norwegian Polar Institute , Fram Centre , Tromsø NO-9296 , Norway
| | - Jon Aars
- Norwegian Polar Institute , Fram Centre , Tromsø NO-9296 , Norway
| | - Magnus Andersen
- Norwegian Polar Institute , Fram Centre , Tromsø NO-9296 , Norway
| | - Anuschka Polder
- Norwegian University of Life Science , Campus Adamstua , Oslo NO-1432 , Norway
| | - Sophie Bourgeon
- UiT-The Arctic University of Norway , Department of Arctic and Marine Biology , Tromsø NO-9010 , Norway
| | - Benjamin Merkel
- Norwegian Polar Institute , Fram Centre , Tromsø NO-9296 , Norway
| | - Andrew D Lowther
- Norwegian Polar Institute , Fram Centre , Tromsø NO-9296 , Norway
| | | | - Jeffrey M Welker
- Department of Biological Sciences , University of Alaska-Anchorage , Anchorage , Alaska 99508 , United States
- Department of Arctic Technology , University Center in Svalbard , Longyearbyen, Svalbard NO-9171 , Norway
| | - Andrew E Derocher
- Department of Biological Sciences , University of Alberta , Edmonton T6G 2R3 , Canada
| | - Bjørn Munro Jenssen
- Department of Arctic Technology , University Center in Svalbard , Longyearbyen, Svalbard NO-9171 , Norway
- Department of Biology , Norwegian University of Science and Technology , Trondheim NO-7491 , Norway
| | - Heli Routti
- Norwegian Polar Institute , Fram Centre , Tromsø NO-9296 , Norway
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Rode KD, Wilson RR, Douglas DC, Muhlenbruch V, Atwood TC, Regehr EV, Richardson ES, Pilfold NW, Derocher AE, Durner GM, Stirling I, Amstrup SC, St Martin M, Pagano AM, Simac K. Spring fasting behavior in a marine apex predator provides an index of ecosystem productivity. Glob Chang Biol 2018; 24:410-423. [PMID: 28994242 DOI: 10.1111/gcb.13933] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2017] [Accepted: 08/02/2017] [Indexed: 05/27/2023]
Abstract
The effects of declining Arctic sea ice on local ecosystem productivity are not well understood but have been shown to vary inter-specifically, spatially, and temporally. Because marine mammals occupy upper trophic levels in Arctic food webs, they may be useful indicators for understanding variation in ecosystem productivity. Polar bears (Ursus maritimus) are apex predators that primarily consume benthic and pelagic-feeding ice-associated seals. As such, their productivity integrates sea ice conditions and the ecosystem supporting them. Declining sea ice availability has been linked to negative population effects for polar bears but does not fully explain observed population changes. We examined relationships between spring foraging success of polar bears and sea ice conditions, prey productivity, and general patterns of ecosystem productivity in the Beaufort and Chukchi Seas (CSs). Fasting status (≥7 days) was estimated using serum urea and creatinine levels of 1,448 samples collected from 1,177 adult and subadult bears across three subpopulations. Fasting increased in the Beaufort Sea between 1983-1999 and 2000-2016 and was related to an index of ringed seal body condition. This change was concurrent with declines in body condition of polar bears and observed changes in the diet, condition and/or reproduction of four other vertebrate consumers within the food chain. In contrast, fasting declined in CS polar bears between periods and was less common than in the two Beaufort Sea subpopulations consistent with studies demonstrating higher primary productivity and maintenance or improved body condition in polar bears, ringed seals, and bearded seals despite recent sea ice loss in this region. Consistency between regional and temporal variation in spring polar bear fasting and food web productivity suggests that polar bears may be a useful indicator species. Furthermore, our results suggest that spatial and temporal ecological variation is important in affecting upper trophic-level productivity in these marine ecosystems.
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Affiliation(s)
- Karyn D Rode
- U.S. Geological Survey, Alaska Science Center, Anchorage, AK, USA
| | - Ryan R Wilson
- U.S. Fish and Wildlife Service, Marine Mammals Management, Anchorage, AK, USA
| | - David C Douglas
- U.S. Geological Survey, Alaska Science Center, Juneau, AK, USA
| | | | - Todd C Atwood
- U.S. Geological Survey, Alaska Science Center, Anchorage, AK, USA
| | - Eric V Regehr
- U.S. Fish and Wildlife Service, Marine Mammals Management, Anchorage, AK, USA
| | - Evan S Richardson
- Wildlife Research Division, Science and Technology Branch, Environment Canada, Edmonton, AB, Canada
| | - Nicholas W Pilfold
- Institute for Conservation Research, San Diego Zoo Global, Escondido, CA, USA
| | - Andrew E Derocher
- Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada
| | - George M Durner
- U.S. Geological Survey, Alaska Science Center, Anchorage, AK, USA
| | - Ian Stirling
- Wildlife Research Division, Science and Technology Branch, Environment Canada, Edmonton, AB, Canada
- Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada
| | - Steven C Amstrup
- Polar Bears International, Bozeman, MT, USA
- Department of Zoology and Physiology, University of Wyoming, Laramie, WY, USA
| | - Michelle St Martin
- U.S. Fish and Wildlife Service, Marine Mammals Management, Anchorage, AK, USA
| | - Anthony M Pagano
- U.S. Geological Survey, Alaska Science Center, Anchorage, AK, USA
| | - Kristin Simac
- U.S. Geological Survey, Alaska Science Center, Anchorage, AK, USA
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Pilfold NW, Hedman D, Stirling I, Derocher AE, Lunn NJ, Richardson E. Mass Loss Rates of Fasting Polar Bears. Physiol Biochem Zool 2016; 89:377-88. [DOI: 10.1086/687988] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Cherry SG, Derocher AE, Lunn NJ. Habitat-mediated timing of migration in polar bears: an individual perspective. Ecol Evol 2016; 6:5032-42. [PMID: 27547331 PMCID: PMC4979725 DOI: 10.1002/ece3.2233] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Revised: 05/12/2016] [Accepted: 05/16/2016] [Indexed: 11/27/2022] Open
Abstract
Migration phenology is largely determined by how animals respond to seasonal changes in environmental conditions. Our perception of the relationship between migratory behavior and environmental cues can vary depending on the spatial scale at which these interactions are measured. Understanding the behavioral mechanisms behind population‐scale movements requires knowledge of how individuals respond to local cues. We show how time‐to‐event models can be used to predict what factors are associated with the timing of an individual's migratory behavior using data from GPS collared polar bears (Ursus maritimus) that move seasonally between sea ice and terrestrial habitats. We found the concentration of sea ice that bears experience at a local level, along with the duration of exposure to these conditions, was most associated with individual migration timing. Our results corroborate studies that assume thresholds of >50% sea ice concentration are necessary for suitable polar bear habitat; however, continued periods (e.g., days to weeks) of exposure to suboptimal ice concentrations during seasonal melting were required before the proportion of bears migrating to land increased substantially. Time‐to‐event models are advantageous for examining individual movement patterns because they account for the idea that animals make decisions based on an accumulation of knowledge from the landscapes they move through and not simply the environment they are exposed to at the time of a decision. Understanding the migration behavior of polar bears moving between terrestrial and marine habitat, at multiple spatiotemporal scales, will be a major aspect of quantifying observed and potential demographic responses to climate‐induced environmental changes.
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Affiliation(s)
- Seth G Cherry
- Department of Biological Sciences University of Alberta Edmonton AB T6G 2E9 Canada
| | - Andrew E Derocher
- Department of Biological Sciences University of Alberta Edmonton AB T6G 2E9 Canada
| | - Nicholas J Lunn
- Environment and Climate Change Canada University of Alberta CW405 Biological Sciences Building Edmonton AB T6G 2E9 Canada
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Auger-Méthé M, Derocher AE, DeMars CA, Plank MJ, Codling EA, Lewis MA. Evaluating random search strategies in three mammals from distinct feeding guilds. J Anim Ecol 2016; 85:1411-21. [DOI: 10.1111/1365-2656.12562] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Accepted: 05/29/2016] [Indexed: 11/28/2022]
Affiliation(s)
- Marie Auger-Méthé
- Department of Biological Sciences; University of Alberta; Edmonton AB Canada T6G 2E9
| | - Andrew E. Derocher
- Department of Biological Sciences; University of Alberta; Edmonton AB Canada T6G 2E9
| | - Craig A. DeMars
- Department of Biological Sciences; University of Alberta; Edmonton AB Canada T6G 2E9
| | - Michael J. Plank
- School of Mathematics and Statistics; University of Canterbury; Christchurch Private Bag 4800 New Zealand
| | - Edward A. Codling
- Department of Mathematical Sciences; University of Essex; Colchester CO4 3SQ UK
| | - Mark A. Lewis
- Department of Biological Sciences; University of Alberta; Edmonton AB Canada T6G 2E9
- Department of Mathematical and Statistical Sciences; Centre for Mathematical Biology; University of Alberta; Edmonton AB Canada T6G 2G1
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Smereka CA, Edwards MA, Pongracz J, Branigan M, Pilfold NW, Derocher AE. Den selection by barren-ground grizzly bears, Mackenzie Delta, Northwest Territories. Polar Biol 2016. [DOI: 10.1007/s00300-016-1974-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Auger-Méthé M, Field C, Albertsen CM, Derocher AE, Lewis MA, Jonsen ID, Mills Flemming J. State-space models' dirty little secrets: even simple linear Gaussian models can have estimation problems. Sci Rep 2016; 6:26677. [PMID: 27220686 PMCID: PMC4879567 DOI: 10.1038/srep26677] [Citation(s) in RCA: 85] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2015] [Accepted: 05/05/2016] [Indexed: 11/17/2022] Open
Abstract
State-space models (SSMs) are increasingly used in ecology to model time-series such as animal movement paths and population dynamics. This type of hierarchical model is often structured to account for two levels of variability: biological stochasticity and measurement error. SSMs are flexible. They can model linear and nonlinear processes using a variety of statistical distributions. Recent ecological SSMs are often complex, with a large number of parameters to estimate. Through a simulation study, we show that even simple linear Gaussian SSMs can suffer from parameter- and state-estimation problems. We demonstrate that these problems occur primarily when measurement error is larger than biological stochasticity, the condition that often drives ecologists to use SSMs. Using an animal movement example, we show how these estimation problems can affect ecological inference. Biased parameter estimates of a SSM describing the movement of polar bears (Ursus maritimus) result in overestimating their energy expenditure. We suggest potential solutions, but show that it often remains difficult to estimate parameters. While SSMs are powerful tools, they can give misleading results and we urge ecologists to assess whether the parameters can be estimated accurately before drawing ecological conclusions from their results.
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Affiliation(s)
- Marie Auger-Méthé
- Dalhousie University, Department of Mathematics and Statistics, Halifax, B3H 4R2, Canada
| | - Chris Field
- Dalhousie University, Department of Mathematics and Statistics, Halifax, B3H 4R2, Canada
| | - Christoffer M. Albertsen
- Technical University of Denmark, National Institute of Aquatic Resources, Charlottenlund, 2920, Denmark
| | - Andrew E. Derocher
- University of Alberta, Department of Biological Sciences, Edmonton, T6G 2E9, Canada
| | - Mark A. Lewis
- University of Alberta, Department of Biological Sciences, Edmonton, T6G 2E9, Canada
- University of Alberta, Department of Mathematical and Statistical Sciences, Edmonton, T6G 2G1, Canada
| | - Ian D. Jonsen
- Macquarie University, Department of Biological Sciences, Sydney, 2109, Australia
| | - Joanna Mills Flemming
- Dalhousie University, Department of Mathematics and Statistics, Halifax, B3H 4R2, Canada
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Bechshoft T, Derocher AE, Richardson E, Lunn NJ, St Louis VL. Hair Mercury Concentrations in Western Hudson Bay Polar Bear Family Groups. Environ Sci Technol 2016; 50:5313-5319. [PMID: 27095340 DOI: 10.1021/acs.est.6b00483] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Methylmercury is one of the more toxic forms of mercury (Hg), the biomagnification of which is prevalent in the Arctic where apex predators such as polar bears (Ursus maritimus) can carry high loads. The maternal transfer of contaminants to offspring is a concern, as offspring may be particularly sensitive to the effects of environmental pollutants during early development. However, few studies of polar bears report on Hg in dependent young. We examined hair total Hg (THg) concentrations in 24 polar bear family groups in western Hudson Bay: mother, cub-of-the-year (COY), yearling, and 2 year old. THg concentrations increased with bear age, with COYs having lower concentrations than other offspring groups (p ≤ 0.008). Using AICc-based regression models, we found maternal THg to be positively related to body condition and litter size, while overall offspring THg was positively related to maternal body condition in addition to being dependent on the sex and age of the offspring. COY THg concentrations were positively related to maternal THg while also depending on the sex of the offspring. Considering our results, future studies in polar bear ecotoxicology are encouraged to include offspring of different ages and sexes.
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Affiliation(s)
- Thea Bechshoft
- Department of Biological Sciences, University of Alberta , Edmonton, Alberta T6G 2E9, Canada
| | - Andrew E Derocher
- Department of Biological Sciences, University of Alberta , Edmonton, Alberta T6G 2E9, Canada
| | - Evan Richardson
- Wildlife Research Division, Science and Technology Branch, Environment and Climate Change Canada, University of Alberta , CW405, Biological Sciences Building, Edmonton, AB T6G 2E9, Canada
| | - Nicholas J Lunn
- Wildlife Research Division, Science and Technology Branch, Environment and Climate Change Canada, University of Alberta , CW405, Biological Sciences Building, Edmonton, AB T6G 2E9, Canada
| | - Vincent L St Louis
- Department of Biological Sciences, University of Alberta , Edmonton, Alberta T6G 2E9, Canada
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Cullingham CI, Thiessen CD, Derocher AE, Paquet PC, Miller JM, Hamilton JA, Coltman DW. Population structure and dispersal of wolves in the Canadian Rocky Mountains. J Mammal 2016. [DOI: 10.1093/jmammal/gyw015] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Robinson BG, Franke A, Derocher AE. Estimating nestling diet with cameras: quantifying uncertainty from unidentified food items. Wildlife Biology 2015. [DOI: 10.2981/wlb.00114] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
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Peacock E, Sonsthagen SA, Obbard ME, Boltunov A, Regehr EV, Ovsyanikov N, Aars J, Atkinson SN, Sage GK, Hope AG, Zeyl E, Bachmann L, Ehrich D, Scribner KT, Amstrup SC, Belikov S, Born EW, Derocher AE, Stirling I, Taylor MK, Wiig Ø, Paetkau D, Talbo SL. Correction: Implications of the circumpolar genetic structure of polar bears for their conservation in a rapidly warming Arctic. PLoS One 2015; 10:e0136126. [PMID: 26273835 PMCID: PMC4537302 DOI: 10.1371/journal.pone.0136126] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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