1
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Chen SC, Musat F, Richnow HH, Krüger M. Microbial diversity and oil biodegradation potential of northern Barents Sea sediments. J Environ Sci (China) 2024; 146:283-297. [PMID: 38969457 DOI: 10.1016/j.jes.2023.12.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Revised: 11/29/2023] [Accepted: 12/07/2023] [Indexed: 07/07/2024]
Abstract
The Arctic, an essential ecosystem on Earth, is subject to pronounced anthropogenic pressures, most notable being the climate change and risks of crude oil pollution. As crucial elements of Arctic environments, benthic microbiomes are involved in climate-relevant biogeochemical cycles and hold the potential to remediate upcoming contamination. Yet, the Arctic benthic microbiomes are among the least explored biomes on the planet. Here we combined geochemical analyses, incubation experiments, and microbial community profiling to detail the biogeography and biodegradation potential of Arctic sedimentary microbiomes in the northern Barents Sea. The results revealed a predominance of bacterial and archaea phyla typically found in the deep marine biosphere, such as Chloroflexi, Atribacteria, and Bathyarcheaota. The topmost benthic communities were spatially structured by sedimentary organic carbon, lacking a clear distinction among geographic regions. With increasing sediment depth, the community structure exhibited stratigraphic variability that could be correlated to redox geochemistry of sediments. The benthic microbiomes harbored multiple taxa capable of oxidizing hydrocarbons using aerobic and anaerobic pathways. Incubation of surface sediments with crude oil led to proliferation of several genera from the so-called rare biosphere. These include Alkalimarinus and Halioglobus, previously unrecognized as hydrocarbon-degrading genera, both harboring the full genetic potential for aerobic alkane oxidation. These findings increase our understanding of the taxonomic inventory and functional potential of unstudied benthic microbiomes in the Arctic.
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Affiliation(s)
- Song-Can Chen
- Department of Isotope Biogeochemistry, Helmholtz Centre for Environmental Research-UFZ, Leipzig, Germany; Division of Microbial Ecology, Department of Microbiology and Ecosystem Science, University of Vienna, Vienna, Austria
| | - Florin Musat
- Department of Biology, Section for Microbiology, Aarhus University, Aarhus, Denmark; Department of Molecular Biology and Biotechnology, Faculty of Biology and Geology, Babeș-Bolyai University, Cluj-Napoca, Romania.
| | - Hans-Hermann Richnow
- Department of Isotope Biogeochemistry, Helmholtz Centre for Environmental Research-UFZ, Leipzig, Germany
| | - Martin Krüger
- Federal Institute for Geosciences and Natural Resources (BGR), Stilleweg 2, 30655, Hannover, Germany
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2
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Aldrich ED, Hendrickson DA, Schmitt TL, Nollens HH, Montano G, Steinman KJ, O’Brien JK, Robeck TR. Laparoscopic Evaluation of the Reproductive Tract in Two Female Polar Bears (Three Procedures) ( Ursus maritimus). Life (Basel) 2024; 14:105. [PMID: 38255720 PMCID: PMC10820367 DOI: 10.3390/life14010105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Revised: 01/03/2024] [Accepted: 01/05/2024] [Indexed: 01/24/2024] Open
Abstract
Polar bears (Ursus maritimus) face a number of challenges that threaten the survival of the species. Captive breeding represents one essential facet of species conservation, but aspects of the polar bear's reproductive physiology, such as follicle maturation, coitus-induced ovulation, and pseudopregnancy, are poorly characterized and present challenges for enhancing natural reproductive success and the application of advanced reproductive techniques. Due to the absence of a reliable transrectal or transabdominal ultrasound method for ovarian examination in the species, the ovaries of two adult female polar bears were examined laparoscopically to evaluate the feasibility of surgical access to the ovaries, oviduct, and uterus. The minimally invasive procedure was easily and rapidly performed in both bears and all procedures. Direct visual assessment of the ovary was possible after dissection of a fatty bursal sac, which completely enclosed the ovaries. In the second bear, laparoscopic manipulation of the ovary to draw it closer to the body wall enabled transcutaneous ultrasound. Laparoscopy may be a valuable tool to aid in the application of advanced reproductive technologies in polar bears.
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Affiliation(s)
- Ellison D. Aldrich
- School of Veterinary Sciences, Massy University, Palmerston North 4442, New Zealand
| | - Dean A. Hendrickson
- College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO 80521, USA
| | - Todd L. Schmitt
- SeaWorld of California, 500 Sea World Drive, San Diego, CA 92109, USA
| | - Hendrik H. Nollens
- Sand Diego Zoo Wildlife Alliance, 15500 San Pasqual Valley Road, Escondido, CA 92027, USA
| | - Gisele Montano
- Species Preservation Laboratory, SeaWorld Parks and Entertainment Corporation, 2595 Ingraham Road, San Diego, CA 92109, USA (T.R.R.)
| | - Karen J. Steinman
- Species Preservation Laboratory, SeaWorld Parks and Entertainment Corporation, 2595 Ingraham Road, San Diego, CA 92109, USA (T.R.R.)
| | | | - Todd R. Robeck
- Species Preservation Laboratory, SeaWorld Parks and Entertainment Corporation, 2595 Ingraham Road, San Diego, CA 92109, USA (T.R.R.)
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3
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Fry TL, Owens LA, Ketz AC, Atwood TC, Dunay E, Goldberg TL. Serum Virome of Southern Beaufort Sea polar bears ( Ursus maritimus) during a period of rapid climate change. CONSERVATION PHYSIOLOGY 2023; 11:coad054. [PMID: 39070777 PMCID: PMC10375943 DOI: 10.1093/conphys/coad054] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Revised: 06/02/2023] [Accepted: 07/07/2023] [Indexed: 07/30/2024]
Abstract
Climate change affects the behavior, physiology and life history of many Arctic wildlife species. It can also influence the distribution and ecology of infectious agents. The southern Beaufort Sea (SB) subpopulation of polar bears (Ursus maritimus) has experienced dramatic behavioral changes due to retreating sea ice and other climate-related factors, but the effects of these changes on physiology and infection remain poorly understood. Using serum from polar bears sampled between 2004 and 2015 and metagenomic DNA sequencing, we identified 48 viruses, all of the family Anelloviridae. Anelloviruses are small, ubiquitous infectious agents with circular single-stranded DNA genomes that are not known to cause disease but, in humans, covary in diversity and load with immunological compromise. We therefore examined the usefulness of anelloviruses as biomarkers of polar bear physiological stress related to climate and habitat use. Polar bear anelloviruses sorted into two distinct clades on a phylogenetic tree, both of which also contained anelloviruses of giant pandas (Ailuropoda melanoleuca), another ursid. Neither anellovirus diversity nor load were associated with any demographic variables, behavioral factors or direct physiological measures. However, pairwise genetic distances between anelloviruses were positively correlated with pairwise differences in sampling date, suggesting that the polar bear "anellome" is evolving over time. These findings suggest that anelloviruses are not a sensitive indicator of polar physiological stress, but they do provide a baseline for evaluating future changes to polar bear viromes.
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Affiliation(s)
- Tricia L Fry
- School of Veterinary Medicine, University of Wisconsin, Madison, WI, 53706
| | - Leah A Owens
- School of Veterinary Medicine, University of Wisconsin, Madison, WI, 53706
| | - Alison C Ketz
- Wisconsin Cooperative Research Unit, Department of Forest and Wildlife Ecology, University of Wisconsin, Madison, WI, 53706
| | - Todd C Atwood
- Alaska Science Center, U. S. Geological Survey, Anchorage, AK 99508
| | - Emily Dunay
- School of Veterinary Medicine, University of Wisconsin, Madison, WI, 53706
| | - Tony L Goldberg
- School of Veterinary Medicine, University of Wisconsin, Madison, WI, 53706
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4
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Brandhuber M, Atkinson S, Cunningham C, Roth T, Curry E. Assessing Dehydroepiandrosterone Sulfate (DHEAS) as a novel biomarker for monitoring estrus and successful reproduction in polar bears. Gen Comp Endocrinol 2023; 338:114276. [PMID: 36940836 PMCID: PMC10319433 DOI: 10.1016/j.ygcen.2023.114276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Revised: 03/13/2023] [Accepted: 03/17/2023] [Indexed: 03/23/2023]
Abstract
Polar bears (Ursus maritimus) in the wild are under threat due to climate change, primarily loss of sea ice, and experience poor reproductive success in zoos. The polar bear is a seasonally polyestrous species that exhibits embryonic diapause and pseudopregnancy, complicating characterization of reproductive function. Fecal excretion of testosterone and progesterone have been studied in polar bears, but accurately predicting reproductive success remains difficult. Dehydroepiandrosterone (DHEA) is a steroid hormone precursor correlated with reproductive success in other species, but has not been well studied in the polar bear. The purpose of the present study was to characterize the longitudinal excretion of DHEAS, the sulfated form of DHEA, from zoo-housed polar bears using a validated enzyme immunoassay. Lyophilized fecal samples from parturient females (n = 10), breeding non-parturient females (n = 11), a non-breeding adult female, a juvenile female, and a breeding adult male were investigated. Five of the breeding non-parturient females had been previously contracepted, while six were never contracepted. DHEAS concentrations were closely associated with testosterone concentrations (p < 0.05, rho > 0.57) for all reproductive statuses. Breeding females exhibited statistically significant (p < 0.05) increases in DHEAS concentration on or near breeding dates, which were not observed outside of the breeding season, or in the non-breeding or juvenile animals. Breeding non-parturient females exhibited higher median and baseline DHEAS concentrations than parturient females over the course of the breeding season. Previously contracepted (PC) breeding non-parturient females also exhibited higher season-long median and baseline DHEAS concentrations than non-previously (NPC) contracepted breeding non-parturient females. These findings suggest that DHEA is related to estrus or ovulation in the polar bear, that there is an optimal DHEA concentration window, and concentrations exceeding that threshold may be associated with reproductive dysfunction.
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Affiliation(s)
- Monica Brandhuber
- University of Alaska Fairbanks, College of Fisheries and Ocean Sciences, Fisheries Dept., Juneau Center, 17101 Pt. Lena Loop Road, Juneau, AK 99801, USA.
| | - Shannon Atkinson
- University of Alaska Fairbanks, College of Fisheries and Ocean Sciences, Fisheries Dept., Juneau Center, 17101 Pt. Lena Loop Road, Juneau, AK 99801, USA.
| | - Curry Cunningham
- University of Alaska Fairbanks, College of Fisheries and Ocean Sciences, Fisheries Dept., Juneau Center, 17101 Pt. Lena Loop Road, Juneau, AK 99801, USA.
| | - Terri Roth
- Center for Conservation and Research of Endangered Wildlife (CREW), Cincinnati Zoo and Botanical Garden, 3400 Vine Street, Cincinnati, OH 45220, USA.
| | - Erin Curry
- Center for Conservation and Research of Endangered Wildlife (CREW), Cincinnati Zoo and Botanical Garden, 3400 Vine Street, Cincinnati, OH 45220, USA.
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5
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Rode KD, Douglas D, Atwood T, Durner G, Wilson R, Pagano A. Observed and forecasted changes in land use by polar bears in the Beaufort and Chukchi Seas, 1985–2040. Glob Ecol Conserv 2022. [DOI: 10.1016/j.gecco.2022.e02319] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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6
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McKinney MA, Chételat J, Burke SM, Elliott KH, Fernie KJ, Houde M, Kahilainen KK, Letcher RJ, Morris AD, Muir DCG, Routti H, Yurkowski DJ. Climate change and mercury in the Arctic: Biotic interactions. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 834:155221. [PMID: 35427623 DOI: 10.1016/j.scitotenv.2022.155221] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Revised: 03/18/2022] [Accepted: 04/08/2022] [Indexed: 06/14/2023]
Abstract
Global climate change has led to profound alterations of the Arctic environment and ecosystems, with potential secondary effects on mercury (Hg) within Arctic biota. This review presents the current scientific evidence for impacts of direct physical climate change and indirect ecosystem change on Hg exposure and accumulation in Arctic terrestrial, freshwater, and marine organisms. As the marine environment is elevated in Hg compared to the terrestrial environment, terrestrial herbivores that now exploit coastal/marine foods when terrestrial plants are iced over may be exposed to higher Hg concentrations. Conversely, certain populations of predators, including Arctic foxes and polar bears, have shown lower Hg concentrations related to reduced sea ice-based foraging and increased land-based foraging. How climate change influences Hg in Arctic freshwater fishes is not clear, but for lacustrine populations it may depend on lake-specific conditions, including interrelated alterations in lake ice duration, turbidity, food web length and energy sources (benthic to pelagic), and growth dilution. In several marine mammal and seabird species, tissue Hg concentrations have shown correlations with climate and weather variables, including climate oscillation indices and sea ice trends; these findings suggest that wind, precipitation, and cryosphere changes that alter Hg transport and deposition are impacting Hg concentrations in Arctic marine organisms. Ecological changes, including northward range shifts of sub-Arctic species and altered body condition, have also been shown to affect Hg levels in some populations of Arctic marine species. Given the limited number of populations and species studied to date, especially within Arctic terrestrial and freshwater systems, further research is needed on climate-driven processes influencing Hg concentrations in Arctic ecosystems and their net effects. Long-term pan-Arctic monitoring programs should consider ancillary datasets on climate, weather, organism ecology and physiology to improve interpretation of spatial variation and time trends of Hg in Arctic biota.
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Affiliation(s)
- Melissa A McKinney
- Department of Natural Resource Sciences, McGill University, Sainte-Anne-de-Bellevue, QC H9X 3 V9, Canada.
| | - John Chételat
- Ecotoxicology & Wildlife Health, Environment and Climate Change Canada, National Wildlife Research Centre, Carleton University, Ottawa, ON K1A 0H3, Canada
| | - Samantha M Burke
- Minnow Aquatic Environmental Services, Guelph, ON N1H 1E9, Canada
| | - Kyle H Elliott
- Department of Natural Resource Sciences, McGill University, Sainte-Anne-de-Bellevue, QC H9X 3 V9, Canada
| | - Kim J Fernie
- Ecotoxicology & Wildlife Health, Environment and Climate Change Canada, Burlington, ON L7S 1A1, Canada
| | - Magali Houde
- Aquatic Contaminants Research Division, Environment and Climate Change Canada, Montréal, QC H2Y 5E7, Canada
| | - Kimmo K Kahilainen
- Lammi Biological Station, University of Helsinki, FI-16900 Lammi, Finland
| | - Robert J Letcher
- Ecotoxicology & Wildlife Health, Environment and Climate Change Canada, National Wildlife Research Centre, Carleton University, Ottawa, ON K1A 0H3, Canada
| | - Adam D Morris
- Northern Contaminants Program, Crown-Indigenous Relations and Northern Affairs Canada, Gatineau, QC J8X 2V6, Canada
| | - Derek C G Muir
- Aquatic Contaminants Research Division, Environment and Climate Change Canada, Burlington, ON L7S 1A1, Canada
| | - Heli Routti
- Norwegian Polar Institute, Fram Centre, NO-9296 Tromsø, Norway
| | - David J Yurkowski
- Arctic Aquatic Research Division, Fisheries and Oceans Canada, Winnipeg, MB R3T 2N6, Canada
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7
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Smith MEK, Horstmann L, Stimmelmayr R. Stable isotope differences of polar bears in the Southern Beaufort Sea and Chukchi Sea. J Wildl Manage 2022. [DOI: 10.1002/jwmg.22225] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Malia E. K. Smith
- College of Fisheries and Ocean Sciences, University of Alaska Fairbanks 2120 Koyukuk Drive Fairbanks AK 99775 USA
| | - Lara Horstmann
- College of Fisheries and Ocean Sciences, University of Alaska Fairbanks 2120 Koyukuk Drive Fairbanks AK 99775 USA
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8
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Laidre KL, Supple MA, Born EW, Regehr EV, Wiig Ø, Ugarte F, Aars J, Dietz R, Sonne C, Hegelund P, Isaksen C, Akse GB, Cohen B, Stern HL, Moon T, Vollmers C, Corbett-Detig R, Paetkau D, Shapiro B. Glacial ice supports a distinct and undocumented polar bear subpopulation persisting in late 21st-century sea-ice conditions. Science 2022; 376:1333-1338. [PMID: 35709290 DOI: 10.1126/science.abk2793] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Polar bears are susceptible to climate warming because of their dependence on sea ice, which is declining rapidly. We present the first evidence for a genetically distinct and functionally isolated group of polar bears in Southeast Greenland. These bears occupy sea-ice conditions resembling those projected for the High Arctic in the late 21st century, with an annual ice-free period that is >100 days longer than the estimated fasting threshold for the species. Whereas polar bears in most of the Arctic depend on annual sea ice to catch seals, Southeast Greenland bears have a year-round hunting platform in the form of freshwater glacial mélange. This suggests that marine-terminating glaciers, although of limited availability, may serve as previously unrecognized climate refugia. Conservation of Southeast Greenland polar bears, which meet criteria for recognition as the world's 20th polar bear subpopulation, is necessary to preserve the genetic diversity and evolutionary potential of the species.
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Affiliation(s)
- Kristin L Laidre
- Polar Science Center, Applied Physics Laboratory, University of Washington, Seattle, WA 98105, USA.,Greenland Institute of Natural Resources, 3900 Nuuk, Greenland
| | - Megan A Supple
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, Santa Cruz, CA 95064, USA
| | - Erik W Born
- Greenland Institute of Natural Resources, 3900 Nuuk, Greenland
| | - Eric V Regehr
- Polar Science Center, Applied Physics Laboratory, University of Washington, Seattle, WA 98105, USA
| | - Øystein Wiig
- Natural History Museum, University of Oslo, Blindern, NO-0318 Oslo, Norway
| | - Fernando Ugarte
- Greenland Institute of Natural Resources, 3900 Nuuk, Greenland
| | - Jon Aars
- Norwegian Polar Institute, Fram Centre, NO-9296 Tromsø, Norway
| | - Rune Dietz
- Department of Ecoscience and Arctic Research Centre, Aarhus University, DK-4000 Roskilde, Denmark
| | - Christian Sonne
- Department of Ecoscience and Arctic Research Centre, Aarhus University, DK-4000 Roskilde, Denmark
| | - Peter Hegelund
- Greenland Institute of Natural Resources, 3900 Nuuk, Greenland
| | - Carl Isaksen
- Greenland Institute of Natural Resources, 3900 Nuuk, Greenland
| | | | - Benjamin Cohen
- Polar Science Center, Applied Physics Laboratory, University of Washington, Seattle, WA 98105, USA
| | - Harry L Stern
- Polar Science Center, Applied Physics Laboratory, University of Washington, Seattle, WA 98105, USA
| | - Twila Moon
- National Snow and Ice Data Center, Cooperative Institute for Research In Environmental Sciences (CIRES), University of Colorado, Boulder, CO 80309, USA
| | - Christopher Vollmers
- Department of Biomolecular Engineering, University of California, Santa Cruz, Santa Cruz, CA 95064, USA
| | - Russ Corbett-Detig
- Department of Biomolecular Engineering, University of California, Santa Cruz, Santa Cruz, CA 95064, USA
| | - David Paetkau
- Wildlife Genetics International, Nelson, BC V1L 5P9, Canada
| | - Beth Shapiro
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, Santa Cruz, CA 95064, USA.,Howard Hughes Medical Institute, University of California, Santa Cruz, Santa Cruz, CA 95064, USA
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9
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Wilson RR, Martin MS, Regehr EV, Rode KD. Intrapopulation differences in polar bear movement and step selection patterns. MOVEMENT ECOLOGY 2022; 10:25. [PMID: 35606849 PMCID: PMC9128121 DOI: 10.1186/s40462-022-00326-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Accepted: 05/14/2022] [Indexed: 06/15/2023]
Abstract
BACKGROUND The spatial ecology of individuals often varies within a population or species. Identifying how individuals in different classes interact with their environment can lead to a better understanding of population responses to human activities and environmental change and improve population estimates. Most inferences about polar bear (Ursus maritimus) spatial ecology are based on data from adult females due to morphological constraints on applying satellite radio collars to other classes of bears. Recent studies, however, have provided limited movement data for adult males and sub-adults of both sexes using ear-mounted and glue-on tags. We evaluated class-specific movements and step selection patterns for polar bears in the Chukchi Sea subpopulation during spring. METHODS We developed hierarchical Bayesian models to evaluate polar bear movement (i.e., step length and directional persistence) and step selection at the scale of 4-day step lengths. We assessed differences in movement and step selection parameters among the three classes of polar bears (i.e., adult males, sub-adults, and adult females without cubs-of-the-year). RESULTS Adult males had larger step lengths and less directed movements than adult females. Sub-adult movement parameters did not differ from the other classes but point estimates were most similar to adult females. We did not detect differences among polar bear classes in step selection parameters and parameter estimates were consistent with previous studies. CONCLUSIONS Our findings support the use of estimated step selection patterns from adult females as a proxy for other classes of polar bears during spring. Conversely, movement analyses indicated that using data from adult females as a proxy for the movements of adult males is likely inappropriate. We recommend that researchers consider whether it is valid to extend inference derived from adult female movements to other classes, based on the questions being asked and the spatial and temporal scope of the data. Because our data were specific to spring, these findings highlight the need to evaluate differences in movement and step selection during other periods of the year, for which data from ear-mounted and glue-on tags are currently lacking.
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Affiliation(s)
- Ryan R Wilson
- U.S. Fish and Wildlife Service, Marine Mammals Management, Anchorage, AK, USA.
| | - Michelle St Martin
- U.S. Fish and Wildlife Service, Marine Mammals Management, Anchorage, AK, USA
- U.S. Fish and Wildlife Service, Portland, OR, 97266, USA
| | - Eric V Regehr
- Polar Science Center, University of Washington, Seattle, WA, USA
| | - Karyn D Rode
- U.S. Geological Survey, Alaska Science Center, Anchorage, AK, USA
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10
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Summer/fall diet and macronutrient assimilation in an Arctic predator. Oecologia 2022; 198:917-931. [PMID: 35412091 DOI: 10.1007/s00442-022-05155-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Accepted: 03/28/2022] [Indexed: 10/18/2022]
Abstract
Free-ranging predator diet estimation is commonly achieved by applying molecular-based tracers because direct observation is not logistically feasible or robust. However, tracers typically do not represent all dietary macronutrients, which likely obscures resource use as prey proximate composition varies and tissue consumption can be specific. For example, polar bears (Ursus maritimus) preferentially consume blubber, yet diets have been estimated using fatty acids based on prey blubber or stable isotopes of lipid-extracted prey muscle, neither of which represent both protein and lipid macronutrient contributions. Further, additional bias can be introduced because dietary fat is known to be flexibly routed beyond short-term energy production and storage. We address this problem by simultaneously accounting for protein and lipid assimilation using carbon and nitrogen isotope compositions of lipid-containing prey muscle and blubber to infer summer/fall diet composition and macronutrient proportions from Chukchi Sea polar bear guard hair (n = 229) sampled each spring between 2008 and 2017. Inclusion of blubber (85-95% lipid by dry mass) expanded the isotope mixing space and improved separation among prey species. Ice-associated seals, including nutritionally dependent pups, were the primary prey in summer/fall diets with lower contributions by Pacific walruses (Odobenus rosmarus) and whales. Percent blubber estimates confirmed preferential selection of this tissue and represented the highest documented lipid assimilation for any animal species. Our results offer an improved understanding of summer/fall prey macronutrient usage by Chukchi Sea polar bears which likely coincides with a nutritional bottleneck as the sea ice minimum is approached.
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11
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Hayward KM, Clemente-Carvalho RBG, Jensen EL, de Groot PVC, Branigan M, Dyck M, Tschritter C, Sun Z, Lougheed SC. Genotyping-in-thousands by sequencing (GT-seq) of non-invasive fecal and degraded samples: a new panel to enable ongoing monitoring of Canadian polar bear populations. Mol Ecol Resour 2022; 22:1906-1918. [PMID: 35007402 PMCID: PMC9305793 DOI: 10.1111/1755-0998.13583] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 11/25/2021] [Accepted: 12/07/2021] [Indexed: 11/26/2022]
Abstract
Genetic monitoring using noninvasive samples provides a complement or alternative to traditional population monitoring methods. However, next‐generation sequencing approaches to monitoring typically require high quality DNA and the use of noninvasive samples (e.g., scat) is often challenged by poor DNA quality and contamination by nontarget species. One promising solution is a highly multiplexed sequencing approach called genotyping‐in‐thousands by sequencing (GT‐seq), which can enable cost‐efficient genomics‐based monitoring for populations based on noninvasively collected samples. Here, we develop and validate a GT‐seq panel of 324 single nucleotide polymorphisms (SNPs) optimized for genotyping of polar bears based on DNA from noninvasively collected faecal samples. We demonstrate (1) successful GT‐seq genotyping of DNA from a range of sample sources, including successful genotyping (>50% loci) of 62.9% of noninvasively collected faecal samples determined to contain polar bear DNA; and (2) that we can reliably differentiate individuals, ascertain sex, assess relatedness, and resolve population structure of Canadian polar bear subpopulations based on a GT‐seq panel of 324 SNPs. Our GT‐seq data reveal spatial‐genetic patterns similar to previous polar bear studies but at lesser cost per sample and through use of noninvasively collected samples, indicating the potential of this approach for population monitoring. This GT‐seq panel provides the foundation for a noninvasive toolkit for polar bear monitoring and can contribute to community‐based programmes – a framework which may serve as a model for wildlife conservation and management for species worldwide.
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Affiliation(s)
- Kristen M Hayward
- Department of Biology, Queen's University, Kingston, Ontario, Canada
| | | | - Evelyn L Jensen
- School of Natural and Environmental Sciences, Newcastle University, Newcastle, United Kingdom
| | | | - Marsha Branigan
- Department of Environment and Natural Resources, Government of the Northwest Territories, Inuvik, Northwest Territories, Canada
| | - Markus Dyck
- Department of Environment, Government of Nunavut, Igloolik, Nunavut, Canada
| | | | - Zhengxin Sun
- Department of Biology, Queen's University, Kingston, Ontario, Canada
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12
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Regehr EV, Runge MC, Von Duyke A, Wilson RR, Polasek L, Rode KD, Hostetter NJ, Converse SJ. Demographic risk assessment for a harvested species threatened by climate change: polar bears in the Chukchi Sea. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2021; 31:e02461. [PMID: 34582601 PMCID: PMC9286533 DOI: 10.1002/eap.2461] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 02/09/2021] [Accepted: 04/05/2021] [Indexed: 06/13/2023]
Abstract
Climate change threatens global biodiversity. Many species vulnerable to climate change are important to humans for nutritional, cultural, and economic reasons. Polar bears Ursus maritimus are threatened by sea-ice loss and represent a subsistence resource for Indigenous people. We applied a novel population modeling-management framework that is based on species life history and accounts for habitat loss to evaluate subsistence harvest for the Chukchi Sea (CS) polar bear subpopulation. Harvest strategies followed a state-dependent approach under which new data were used to update the harvest on a predetermined management interval. We found that a harvest strategy with a starting total harvest rate of 2.7% (˜85 bears/yr at current abundance), a 2:1 male-to-female ratio, and a 10-yr management interval would likely maintain subpopulation abundance above maximum net productivity level for the next 35 yr (approximately three polar bear generations), our primary criterion for sustainability. Plausible bounds on starting total harvest rate were 1.7-3.9%, where the range reflects uncertainty due to sampling variation, environmental variation, model selection, and differing levels of risk tolerance. The risk of undesired demographic outcomes (e.g., overharvest) was positively related to harvest rate, management interval, and projected declines in environmental carrying capacity; and negatively related to precision in population data. Results reflect several lines of evidence that the CS subpopulation has been productive in recent years, although it is uncertain how long this will last as sea-ice loss continues. Our methods provide a template for balancing trade-offs among protection, use, research investment, and other factors. Demographic risk assessment and state-dependent management will become increasingly important for harvested species, like polar bears, that exhibit spatiotemporal variation in their response to climate change.
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Affiliation(s)
- Eric V. Regehr
- Polar Science CenterApplied Physics LaboratoryUniversity of WashingtonSeattleWashington98105USA
| | - Michael C. Runge
- Patuxent Wildlife Research CenterU.S. Geological SurveyLaurelMaryland20708USA
| | - Andrew Von Duyke
- Department of Wildlife ManagementNorth Slope BoroughUtqiaġvikAlaska99723USA
| | - Ryan R. Wilson
- Marine Mammals ManagementU.S. Fish and Wildlife ServiceAnchorageAlaska99503USA
| | - Lori Polasek
- Division of Wildlife ConservationAlaska Department of Fish and GameJuneauAlaska99802USA
| | - Karyn D. Rode
- Alaska Science CenterU.S. Geological SurveyAnchorageAlaska99508USA
| | - Nathan J. Hostetter
- Washington Cooperative Fish and Wildlife Research UnitSchool of Aquatic and Fishery SciencesUniversity of WashingtonSeattleWashington98105USA
| | - Sarah J. Converse
- Washington Cooperative Fish and Wildlife Research UnitSchool of Environmental and Forest Sciences (SEFS) & School of Aquatic and Fishery Sciences (SAFS)U.S. Geological SurveyUniversity of WashingtonSeattleWashington98105USA
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13
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Atwood TC, Rode KD, Douglas DC, Simac K, Pagano AM, Bromaghin JF. Long-term variation in polar bear body condition and maternal investment relative to a changing environment. Glob Ecol Conserv 2021. [DOI: 10.1016/j.gecco.2021.e01925] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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14
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A fat chance of survival: Body condition provides life-history dependent buffering of environmental change in a wild mammal population. CLIMATE CHANGE ECOLOGY 2021. [DOI: 10.1016/j.ecochg.2021.100022] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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15
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Hauser DDW, Frost KJ, Burns JJ. Ringed seal (Pusa hispida) breeding habitat on the landfast ice in northwest Alaska during spring 1983 and 1984. PLoS One 2021; 16:e0260644. [PMID: 34843596 PMCID: PMC8629220 DOI: 10.1371/journal.pone.0260644] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Accepted: 11/15/2021] [Indexed: 11/30/2022] Open
Abstract
There has been significant sea ice loss associated with climate change in the Pacific Arctic, with unquantified impacts to the habitat of ice-obligate marine mammals such as ringed seals (Pusa hispida). Ringed seals maintain breathing holes and excavate subnivean lairs on sea ice to provide protection from weather and predators during birthing, nursing, and resting. However, there is limited baseline information on the snow and ice habitat, distribution, density, and configuration of ringed seal structures (breathing holes, simple haul-out lairs, and pup lairs) in Alaska. Here, we describe historic field records from two regions of the eastern Chukchi Sea (Kotzebue Sound and Ledyard Bay) collected during spring 1983 and 1984 to quantify baseline ringed seal breeding habitat and map the distribution of ringed seal structures using modern geospatial tools. Of 490 structures located on pre-established study grids by trained dogs, 29% were pup lairs (25% in Kotzebue Sound and 33% in Ledyard Bay). Grids in Ledyard Bay had greater overall density of seal structures than those in Kotzebue Sound (8.6 structures/km2 and 7.1 structures/km2), but structures were larger in Kotzebue Sound. Pup lairs were located in closer proximity to other structures and characterized by deeper snow and greater ice deformation than haul-out lairs or simple breathing holes. At pup lairs, snow depths averaged 74.9 cm (range 37–132 cm), with ice relief nearby averaging 76 cm (range 31–183 cm), and ice deformation 29.9% (range 5–80%). We compare our results to similar studies conducted in other geographic regions and discuss our findings in the context of recent declines in extent and duration of seasonal cover of landfast sea ice and snow deposition on sea ice. Ultimately, additional research is needed to understand the effects of recent environmental changes on ringed seals, but our study establishes a baseline upon which future research can measure pup habitat in northwest Alaska.
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Affiliation(s)
- Donna D. W. Hauser
- International Arctic Research Center, University of Alaska Fairbanks, Fairbanks, Alaska, United States of America
- * E-mail:
| | - Kathryn J. Frost
- Alaska Department of Fish and Game (retired), Kailua Kona, Hawaii, United States of America
| | - John J. Burns
- Living Resources, Inc., Fairbanks, Alaska, United States of America
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16
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An on-ice aerial survey of the Kane Basin polar bear (Ursus maritimus) subpopulation. Polar Biol 2021; 45:89-100. [PMID: 35125636 PMCID: PMC8776663 DOI: 10.1007/s00300-021-02974-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Revised: 10/16/2021] [Accepted: 11/15/2021] [Indexed: 10/28/2022]
Abstract
AbstractThere is an imminent need to collect information on distribution and abundance of polar bears (Ursus maritimus) to understand how they are affected by the ongoing decrease in Arctic sea ice. The Kane Basin (KB) subpopulation is a group of high-latitude polar bears that ranges between High Arctic Canada and NW Greenland around and north of the North Water polynya (NOW). We conducted a line transect distance sampling aerial survey of KB polar bears during 28 April–12 May 2014. A total of 4160 linear kilometers were flown in a helicopter over fast ice in the fjords and over offshore pack ice between 76° 50′ and 80° N′. Using a mark-recapture distance sampling protocol, the estimated abundance was 190 bears (95% lognormal CI: 87–411; CV 39%). This estimate is likely negatively biased to an unknown degree because the offshore sectors of the NOW with much open water were not surveyed because of logistical and safety reasons. Our study demonstrated that aerial surveys may be a feasible method for obtaining abundance estimates for small subpopulations of polar bears.
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17
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Pagano AM, Durner GM, Atwood TC, Douglas DC. Effects of sea ice decline and summer land use on polar bear home range size in the Beaufort Sea. Ecosphere 2021. [DOI: 10.1002/ecs2.3768] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Affiliation(s)
- Anthony M. Pagano
- U.S. Geological Survey Alaska Science Center Anchorage Alaska 99508 USA
| | - George M. Durner
- U.S. Geological Survey Alaska Science Center Anchorage Alaska 99508 USA
| | - Todd C. Atwood
- U.S. Geological Survey Alaska Science Center Anchorage Alaska 99508 USA
| | - David C. Douglas
- U.S. Geological Survey Alaska Science Center Juneau Alaska 99801 USA
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18
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Fatty acid profiles of feeding and fasting bears: estimating calibration coefficients, the timeframe of diet estimates, and selective mobilization during hibernation. J Comp Physiol B 2021; 192:379-395. [PMID: 34687352 DOI: 10.1007/s00360-021-01414-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Revised: 09/20/2021] [Accepted: 10/03/2021] [Indexed: 10/20/2022]
Abstract
Accurate information on diet composition is central to understanding and conserving carnivore populations. Quantitative fatty acid signature analysis (QFASA) has emerged as a powerful tool for estimating the diets of predators, but ambiguities remain about the timeframe of QFASA estimates and the need to account for species-specific patterns of metabolism. We conducted a series of feeding experiments with four juvenile male brown bears (Ursus arctos) to (1) track the timing of changes in adipose tissue composition and QFASA diet estimates in response to a change in diet and (2) quantify the relationship between consumer and diet FA composition (i.e., determine "calibration coefficients"). Bears were fed three compositionally distinct diets for 90-120 days each. Two marine-based diets were intended to approximate the lipid content and composition of the wild diet of polar bears (U. maritimus). Bear adipose tissue composition changed quickly in the direction of the diet and showed evidence of stabilization after 60 days. During hibernation, FA profiles were initially stable but diet estimates after 10 weeks were sensitive to calibration coefficients. Calibration coefficients derived from the marine-based diets were broadly similar to each other and to published values from marine-fed mink (Mustela vison), which have been used as a model for free-ranging polar bears. For growing bears on a high-fat diet, the temporal window for QFASA estimates was 30-90 days. Although our results reinforce the importance of accurate calibration, the similarities across taxa and diets suggest it may be feasible to develop a generalized QFASA approach for mammalian carnivores.
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19
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Atkinson SN, Laidre KL, Arnold TW, Stapleton S, Regehr EV, Born EW, Wiig Ø, Dyck M, Lunn NJ, Stern HL, Paetkau D. A novel mark-recapture-recovery survey using genetic sampling for polar bears Ursus maritimus in Baffin Bay. ENDANGER SPECIES RES 2021. [DOI: 10.3354/esr01148] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Changes in sea-ice dynamics are affecting polar bears Ursus maritimus across their circumpolar range, which highlights the importance of periodic demographic assessments to inform management and conservation. We used genetic mark-recapture-recovery to derive estimates of abundance and survival for the Baffin Bay (BB) polar bear subpopulation—the first time this method has been used successfully for this species. Genetic data from tissue samples we collected via biopsy darting were combined with historical physical capture and harvest recovery data. The combined data set consisted of 1410 genetic samples (2011-2013), 914 physical captures (1993-1995, 1997), and 234 harvest returns of marked bears (1993-2013). The estimate of mean subpopulation abundance was 2826 (95% CI = 2284-3367) in 2012-2013. Estimates of annual survival (mean ± SE) were 0.90 ± 0.05 and 0.78 ± 0.06 for females and males age ≥2 yr, respectively. The proportion of total mortality of adult females and males that was attributed to legal harvest was 0.16 ± 0.05 and 0.26 ± 0.06, respectively. Remote sensing sea-ice data, telemetry data, and spatial distribution of onshore sampling indicated that polar bears were more likely to use offshore sea-ice habitat during the 1990s sampling period compared to the 2010s. Furthermore, in the 1990s, sampling of deep fjords and inland areas was limited, and no offshore sampling occurred in either time period, which precluded comparisons of abundance between the 1993-1997 and 2011-2013 study periods. Our findings demonstrate that genetic sampling can be a practical method for demographic assessment of polar bears over large spatial and temporal scales.
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Affiliation(s)
- SN Atkinson
- Wildlife Research Section, Department of Environment, Government of Nunavut, Igloolik, NU X0A 0L0, Canada
| | - KL Laidre
- Polar Science Center, Applied Physics Laboratory, University of Washington, Seattle, WA 98105, USA
- Greenland Institute of Natural Resources, 3900 Nuuk, Greenland
| | - TW Arnold
- Department of Fisheries, Wildlife, and Conservation Biology, University of Minnesota, St. Paul, MN 55108, USA
| | - S Stapleton
- Department of Fisheries, Wildlife, and Conservation Biology, University of Minnesota, St. Paul, MN 55108, USA
| | - EV Regehr
- Polar Science Center, Applied Physics Laboratory, University of Washington, Seattle, WA 98105, USA
| | - EW Born
- Greenland Institute of Natural Resources, 3900 Nuuk, Greenland
| | - Ø Wiig
- Natural History Museum, University of Oslo, 0318, Oslo, Norway
| | - M Dyck
- Wildlife Research Section, Department of Environment, Government of Nunavut, Igloolik, NU X0A 0L0, Canada
| | - NJ Lunn
- Environment and Climate Change Canada, University of Alberta, Edmonton, AB T6G 2E9, Canada
| | - HL Stern
- Polar Science Center, Applied Physics Laboratory, University of Washington, Seattle, WA 98105, USA
| | - D Paetkau
- Wildlife Genetics International, Nelson, BC V1L 5P9, Canada
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20
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Bromaghin JF, Douglas DC, Durner GM, Simac KS, Atwood TC. Survival and abundance of polar bears in Alaska's Beaufort Sea, 2001-2016. Ecol Evol 2021; 11:14250-14267. [PMID: 34707852 PMCID: PMC8525099 DOI: 10.1002/ece3.8139] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 08/02/2021] [Accepted: 09/06/2021] [Indexed: 12/20/2022] Open
Abstract
The Arctic Ocean is undergoing rapid transformation toward a seasonally ice-free ecosystem. As ice-adapted apex predators, polar bears (Ursus maritimus) are challenged to cope with ongoing habitat degradation and changes in their prey base driven by food-web response to climate warming. Knowledge of polar bear response to environmental change is necessary to understand ecosystem dynamics and inform conservation decisions. In the southern Beaufort Sea (SBS) of Alaska and western Canada, sea ice extent has declined since satellite observations began in 1979 and available evidence suggests that the carrying capacity of the SBS for polar bears has trended lower for nearly two decades. In this study, we investigated the population dynamics of polar bears in Alaska's SBS from 2001 to 2016 using a multistate Cormack-Jolly-Seber mark-recapture model. States were defined as geographic regions, and we used location data from mark-recapture observations and satellite-telemetered bears to model transitions between states and thereby explain heterogeneity in recapture probabilities. Our results corroborate prior findings that the SBS subpopulation experienced low survival from 2003 to 2006. Survival improved modestly from 2006 to 2008 and afterward rebounded to comparatively high levels for the remainder of the study, except in 2012. Abundance moved in concert with survival throughout the study period, declining substantially from 2003 and 2006 and afterward fluctuating with lower variation around an average of 565 bears (95% Bayesian credible interval [340, 920]) through 2015. Even though abundance was comparatively stable and without sustained trend from 2006 to 2015, polar bears in the Alaska SBS were less abundant over that period than at any time since passage of the U.S. Marine Mammal Protection Act. The potential for recovery is likely limited by the degree of habitat degradation the subpopulation has experienced, and future reductions in carrying capacity are expected given current projections for continued climate warming.
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Affiliation(s)
| | | | | | | | - Todd C. Atwood
- U.S. Geological SurveyAlaska Science CenterAnchorageAKUSA
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21
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Florko KRN, Tai TC, Cheung WWL, Ferguson SH, Sumaila UR, Yurkowski DJ, Auger-Méthé M. Predicting how climate change threatens the prey base of Arctic marine predators. Ecol Lett 2021; 24:2563-2575. [PMID: 34469020 DOI: 10.1111/ele.13866] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Accepted: 08/06/2021] [Indexed: 11/29/2022]
Abstract
Arctic sea ice loss has direct consequences for predators. Climate-driven distribution shifts of native and invasive prey species may exacerbate these consequences. We assessed potential changes by modelling the prey base of a widely distributed Arctic predator (ringed seal; Pusa hispida) in a sentinel area for change (Hudson Bay) under high- and low-greenhouse gas emission scenarios from 1950 to 2100. All changes were relatively negligible under the low-emission scenario, but under the high-emission scenario, we projected a 50% decline in the abundance of the well-distributed, ice-adapted and energy-rich Arctic cod (Boreogadus saida) and an increase in the abundance of smaller temperate-associated fish in southern and coastal areas. Furthermore, our model predicted that all fish species declined in mean body size, but a 29% increase in total prey biomass. Declines in energy-rich prey and restrictions in their spatial range are likely to have cascading effects on Arctic predators.
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Affiliation(s)
- Katie R N Florko
- Institute for the Oceans and Fisheries, University of British Columbia, Vancouver, British Columbia, Canada
| | - Travis C Tai
- Institute for the Oceans and Fisheries, University of British Columbia, Vancouver, British Columbia, Canada
| | - William W L Cheung
- Institute for the Oceans and Fisheries, University of British Columbia, Vancouver, British Columbia, Canada
| | - Steven H Ferguson
- Department of Fisheries and Oceans, Freshwater Institute, Winnipeg, Manitoba, Canada.,Department of Biological Sciences, University of Manitoba, Winnipeg, Manitoba, Canada
| | - U Rashid Sumaila
- Institute for the Oceans and Fisheries, University of British Columbia, Vancouver, British Columbia, Canada
| | - David J Yurkowski
- Department of Fisheries and Oceans, Freshwater Institute, Winnipeg, Manitoba, Canada.,Department of Biological Sciences, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Marie Auger-Méthé
- Institute for the Oceans and Fisheries, University of British Columbia, Vancouver, British Columbia, Canada.,Department of Statistics, University of British Columbia, Vancouver, British Columbia, Canada
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22
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Rode KD, Robbins CT, Stricker CA, Taras BD, Tollefson TN. Energetic and health effects of protein overconsumption constrain dietary adaptation in an apex predator. Sci Rep 2021; 11:15309. [PMID: 34321600 PMCID: PMC8319126 DOI: 10.1038/s41598-021-94917-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2021] [Accepted: 07/19/2021] [Indexed: 12/02/2022] Open
Abstract
Studies of predator feeding ecology commonly focus on energy intake. However, captive predators have been documented to selectively feed to optimize macronutrient intake. As many apex predators experience environmental changes that affect prey availability, limitations on selective feeding can affect energetics and health. We estimated the protein:fat ratio of diets consumed by wild polar bears using a novel isotope-based approach, measured protein:fat ratios selected by zoo polar bears offered dietary choice and examined potential energetic and health consequences of overconsuming protein. Dietary protein levels selected by wild and zoo polar bears were low and similar to selection observed in omnivorous brown bears, which reduced energy intake requirements by 70% compared with lean meat diets. Higher-protein diets fed to zoo polar bears during normal care were concurrent with high rates of mortality from kidney disease and liver cancer. Our results suggest that polar bears have low protein requirements and that limitations on selective consumption of marine mammal blubber consequent to climate change could meaningfully increase their energetic costs. Although bear protein requirements appear lower than those of other carnivores, the energetic and health consequences of protein overconsumption identified in this study have the potential to affect a wide range of taxa.
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Affiliation(s)
- Karyn D Rode
- U.S. Geological Survey, Alaska Science Center, 4210 University Drive, Anchorage, AK, 99508, USA.
| | - Charles T Robbins
- School of the Environment and School of Biological Sciences, Washington State University, Pullman, WA, 99164, USA
| | - Craig A Stricker
- U.S. Geological Survey, Fort Collins Science Center, Fort Collins, CO, 80526, USA
| | - Brian D Taras
- Division of Wildlife Conservation, Alaska Department of Fish and Game, Fairbanks, AK, 99701, USA
| | - Troy N Tollefson
- Mazuri Exotic Animal Nutrition, Land O'Lakes, Inc., St. Louis, MO, 63166, USA
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23
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Lomac-MacNair K, Wisdom S, Pedro De Andrade J, Stepanuk JE, Esteves E. Polar bear behavioral response to vessel surveys in northeastern Chukchi Sea, 2008–2014. URSUS 2021. [DOI: 10.2192/ursus-d-20-00023.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Affiliation(s)
- Kate Lomac-MacNair
- CCMAR, Centro de Ciências do Mar, Universidade do Algarve Campus de Gambelas, 8005-139 Faro, Portugal
| | - Sheyna Wisdom
- Fairweather Science LLC, 301 Calista Court, Anchorage, AK 99518, USA
| | - José Pedro De Andrade
- CCMAR, Centro de Ciências do Mar, Universidade do Algarve Campus de Gambelas, 8005-139 Faro, Portugal
| | - Julia E. Stepanuk
- Department of Ecology and Evolution, Stony Brook University, Stony Brook, NY 11794, USA
| | - Eduardo Esteves
- CCMAR, Centro de Ciências do Mar and Instituto Superior de Engenharia, Universidade do Algarve Campus da Penha, 8005-139 Faro, Portugal
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24
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Rode KD, Regehr EV, Bromaghin JF, Wilson RR, St Martin M, Crawford JA, Quakenbush LT. Seal body condition and atmospheric circulation patterns influence polar bear body condition, recruitment, and feeding ecology in the Chukchi Sea. GLOBAL CHANGE BIOLOGY 2021; 27:2684-2701. [PMID: 33644944 DOI: 10.1111/gcb.15572] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Accepted: 02/10/2021] [Indexed: 06/12/2023]
Abstract
Polar bears (Ursus maritimus) are experiencing loss of sea ice habitats used to access their marine mammal prey. Simultaneously, ocean warming is changing ecosystems that support marine mammal populations. The interactive effects of sea ice and prey are not well understood yet may explain spatial-temporal variation in the response of polar bears to sea ice loss. Here, we examined the potential combined effects of sea ice, seal body condition, and atmospheric circulation patterns on the body condition, recruitment, diet, and feeding probability of 469 polar bears captured in the Chukchi Sea, 2008-2017. The body condition of ringed seals (Pusa hispida), the primary prey of females and subadults, was related to dietary proportions of ringed seal, feeding probability, and the body condition of females and cubs. In contrast, adult males consumed more bearded seals (Erignathus barbatus) and exhibited better condition when bearded seal body condition was higher. The litter size, number of yearlings per adult female, and the condition of dependent young were higher following winters characterized by low Arctic Oscillation conditions, consistent with a growing number of studies. Body condition, recruitment, and feeding probability were either not associated or negatively associated with sea ice conditions, suggesting that, unlike some subpopulations, Chukchi Sea bears are not currently limited by sea ice availability. However, spring sea ice cover declined 2% per year during our study reaching levels not previously observed in the satellite record and resulting in the loss of polar bear hunting and seal pupping habitat. Our study suggests that the status of ice seal populations is likely an important factor that can either compound or mitigate the response of polar bears to sea ice loss over the short term. In the long term, neither polar bears nor their prey are likely robust to limitless loss of their sea ice habitat.
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Affiliation(s)
- Karyn D Rode
- Alaska Science Center, U.S. Geological Survey, Anchorage, AK, USA
| | - Eric V Regehr
- Polar Science Center, University of Washington, Seattle, WA, USA
| | | | - Ryan R Wilson
- Marine Mammals Management, U.S. Fish and Wildlife Service, Anchorage, AK, USA
| | - Michelle St Martin
- Marine Mammals Management, U.S. Fish and Wildlife Service, Anchorage, AK, USA
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25
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Conn PB, Chernook VI, Moreland EE, Trukhanova IS, Regehr EV, Vasiliev AN, Wilson RR, Belikov SE, Boveng PL. Aerial survey estimates of polar bears and their tracks in the Chukchi Sea. PLoS One 2021; 16:e0251130. [PMID: 33956835 PMCID: PMC8101751 DOI: 10.1371/journal.pone.0251130] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Accepted: 04/20/2021] [Indexed: 11/19/2022] Open
Abstract
Polar bears are of international conservation concern due to climate change but are difficult to study because of low densities and an expansive, circumpolar distribution. In a collaborative U.S.-Russian effort in spring of 2016, we used aerial surveys to detect and estimate the abundance of polar bears on sea ice in the Chukchi Sea. Our surveys used a combination of thermal imagery, digital photography, and human observations. Using spatio-temporal statistical models that related bear and track densities to physiographic and biological covariates (e.g., sea ice extent, resource selection functions derived from satellite tags), we predicted abundance and spatial distribution throughout our study area. Estimates of 2016 abundance ([Formula: see text]) ranged from 3,435 (95% CI: 2,300-5,131) to 5,444 (95% CI: 3,636-8,152) depending on the proportion of bears assumed to be missed on the transect line during Russian surveys (g(0)). Our point estimates are larger than, but of similar magnitude to, a recent estimate for the period 2008-2016 ([Formula: see text]; 95% CI 1,522-5,944) derived from an integrated population model applied to a slightly smaller area. Although a number of factors (e.g., equipment issues, differing platforms, low sample sizes, size of the study area relative to sampling effort) required us to make a number of assumptions to generate estimates, it establishes a useful lower bound for abundance, and suggests high spring polar bear densities on sea ice in Russian waters south of Wrangell Island. With future improvements, we suggest that springtime aerial surveys may represent a plausible avenue for studying abundance and distribution of polar bears and their prey over large, remote areas.
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Affiliation(s)
- Paul B. Conn
- Alaska Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, Seattle, Washington, United States of America
- * E-mail:
| | - Vladimir I. Chernook
- Ecological Center, Autonomous Non-Commercial Organization, Saint-Petersburg, Russia
| | - Erin E. Moreland
- Alaska Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, Seattle, Washington, United States of America
| | - Irina S. Trukhanova
- North Pacific Wildlife Consulting, LLC, Seattle, Washington, United States of America
| | - Eric V. Regehr
- Marine Mammals Management, United States Fish and Wildlife Service, Anchorage, Alaska, United States of America
- Applied Physics Laboratory, Polar Science Center, University of Washington, Seattle, Washington, United States of America
| | | | - Ryan R. Wilson
- Marine Mammals Management, United States Fish and Wildlife Service, Anchorage, Alaska, United States of America
| | - Stanislav E. Belikov
- All-Russian Research Institute for Nature Protection (Federal State Budgetary Institution), Moscow, Russia
| | - Peter L. Boveng
- Alaska Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, Seattle, Washington, United States of America
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26
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Aoki K, Isojunno S, Bellot C, Iwata T, Kershaw J, Akiyama Y, Martín López LM, Ramp C, Biuw M, Swift R, Wensveen PJ, Pomeroy P, Narazaki T, Hall A, Sato K, Miller PJO. Aerial photogrammetry and tag-derived tissue density reveal patterns of lipid-store body condition of humpback whales on their feeding grounds. Proc Biol Sci 2021; 288:20202307. [PMID: 33499785 PMCID: PMC7893258 DOI: 10.1098/rspb.2020.2307] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Monitoring the body condition of free-ranging marine mammals at different life-history stages is essential to understand their ecology as they must accumulate sufficient energy reserves for survival and reproduction. However, assessing body condition in free-ranging marine mammals is challenging. We cross-validated two independent approaches to estimate the body condition of humpback whales (Megaptera novaeangliae) at two feeding grounds in Canada and Norway: animal-borne tags (n = 59) and aerial photogrammetry (n = 55). Whales that had a large length-standardized projected area in overhead images (i.e. whales looked fatter) had lower estimated tissue body density (TBD) (greater lipid stores) from tag data. Linking both measurements in a Bayesian hierarchical model to estimate the true underlying (hidden) tissue body density (uTBD), we found uTBD was lower (-3.5 kg m-3) in pregnant females compared to adult males and resting females, while in lactating females it was higher (+6.0 kg m-3). Whales were more negatively buoyant (+5.0 kg m-3) in Norway than Canada during the early feeding season, possibly owing to a longer migration from breeding areas. While uTBD decreased over the feeding season across life-history traits, whale tissues remained negatively buoyant (1035.3 ± 3.8 kg m-3) in the late feeding season. This study adds confidence to the effectiveness of these independent methods to estimate the body condition of free-ranging whales.
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Affiliation(s)
- Kagari Aoki
- Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwa, Chiba 2778564, Japan
| | - Saana Isojunno
- Sea Mammal Research Unit, School of Biology, University of St Andrews, St Andrews, Fife KY16 8LB, UK
| | - Charlotte Bellot
- Department of Marine Biology, University of Neuchâtel, Neuchâtel 2000, Switzerland
| | - Takashi Iwata
- Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwa, Chiba 2778564, Japan
| | - Joanna Kershaw
- Sea Mammal Research Unit, School of Biology, University of St Andrews, St Andrews, Fife KY16 8LB, UK
| | - Yu Akiyama
- Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwa, Chiba 2778564, Japan
| | - Lucía M Martín López
- Sea Mammal Research Unit, School of Biology, University of St Andrews, St Andrews, Fife KY16 8LB, UK.,Asociación Ipar Perspective, Sopela 48600, Spain
| | - Christian Ramp
- Sea Mammal Research Unit, School of Biology, University of St Andrews, St Andrews, Fife KY16 8LB, UK.,Mingan Island Cetacean Study (MICS), St. Lambert, Quebec, Canada G0G 1V0
| | - Martin Biuw
- Fram Centre, Institute of Marine Research, Tromsø N-9296, Norway
| | - René Swift
- Sea Mammal Research Unit, School of Biology, University of St Andrews, St Andrews, Fife KY16 8LB, UK
| | - Paul J Wensveen
- Sea Mammal Research Unit, School of Biology, University of St Andrews, St Andrews, Fife KY16 8LB, UK.,Faculty of Life and Environmental Sciences, University of Iceland, 102 Reykjavik, Iceland
| | - Patrick Pomeroy
- Sea Mammal Research Unit, School of Biology, University of St Andrews, St Andrews, Fife KY16 8LB, UK
| | - Tomoko Narazaki
- Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwa, Chiba 2778564, Japan
| | - Ailsa Hall
- Sea Mammal Research Unit, School of Biology, University of St Andrews, St Andrews, Fife KY16 8LB, UK
| | - Katsufumi Sato
- Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwa, Chiba 2778564, Japan
| | - Patrick J O Miller
- Sea Mammal Research Unit, School of Biology, University of St Andrews, St Andrews, Fife KY16 8LB, UK
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27
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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. CONSERVATION PHYSIOLOGY 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] [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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28
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Synergistic interactions among growing stressors increase risk to an Arctic ecosystem. Nat Commun 2020; 11:6255. [PMID: 33288746 PMCID: PMC7721797 DOI: 10.1038/s41467-020-19899-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Accepted: 10/29/2020] [Indexed: 11/08/2022] Open
Abstract
Oceans provide critical ecosystem services, but are subject to a growing number of external pressures, including overfishing, pollution, habitat destruction, and climate change. Current models typically treat stressors on species and ecosystems independently, though in reality, stressors often interact in ways that are not well understood. Here, we use a network interaction model (OSIRIS) to explicitly study stressor interactions in the Chukchi Sea (Arctic Ocean) due to its extensive climate-driven loss of sea ice and accelerated growth of other stressors, including shipping and oil exploration. The model includes numerous trophic levels ranging from phytoplankton to polar bears. We find that climate-related stressors have a larger impact on animal populations than do acute stressors like increased shipping and subsistence harvesting. In particular, organisms with a strong temperature-growth rate relationship show the greatest changes in biomass as interaction strength increased, but also exhibit the greatest variability. Neglecting interactions between stressors vastly underestimates the risk of population crashes. Our results indicate that models must account for stressor interactions to enable responsible management and decision-making.
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29
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Laidre KL, Atkinson SN, Regehr EV, Stern HL, Born EW, Wiig Ø, Lunn NJ, Dyck M, Heagerty P, Cohen BR. Transient benefits of climate change for a high-Arctic polar bear (Ursus maritimus) subpopulation. GLOBAL CHANGE BIOLOGY 2020; 26:6251-6265. [PMID: 32964662 DOI: 10.1111/gcb.15286] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Accepted: 05/18/2020] [Indexed: 06/11/2023]
Abstract
Kane Basin (KB) is one of the world's most northerly polar bear (Ursus maritimus) subpopulations, where bears have historically inhabited a mix of thick multiyear and annual sea ice year-round. Currently, KB is transitioning to a seasonally ice-free region because of climate change. This ecological shift has been hypothesized to benefit polar bears in the near-term due to thinner ice with increased biological production, although this has not been demonstrated empirically. We assess sea-ice changes in KB together with changes in polar bear movements, seasonal ranges, body condition, and reproductive metrics obtained from capture-recapture (physical and genetic) and satellite telemetry studies during two study periods (1993-1997 and 2012-2016). The annual cycle of sea-ice habitat in KB shifted from a year-round ice platform (~50% coverage in summer) in the 1990s to nearly complete melt-out in summer (<5% coverage) in the 2010s. The mean duration between sea-ice retreat and advance increased from 109 to 160 days (p = .004). Between the 1990s and 2010s, adult female (AF) seasonal ranges more than doubled in spring and summer and were significantly larger in all months. Body condition scores improved for all ages and both sexes. Mean litter sizes of cubs-of-the-year (C0s) and yearlings (C1s), and the number of C1s per AF, did not change between decades. The date of spring sea-ice retreat in the previous year was positively correlated with C1 litter size, suggesting smaller litters following years with earlier sea-ice breakup. Our study provides evidence for range expansion, improved body condition, and stable reproductive performance in the KB polar bear subpopulation. These changes, together with a likely increasing subpopulation abundance, may reflect the shift from thick, multiyear ice to thinner, seasonal ice with higher biological productivity. The duration of these benefits is unknown because, under unmitigated climate change, continued sea-ice loss is expected to eventually have negative demographic and ecological effects on all polar bears.
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Affiliation(s)
- Kristin L Laidre
- Polar Science Center, Applied Physics Laboratory, University of Washington, Seattle, WA, USA
- Greenland Institute of Natural Resources, Nuuk, Greenland
| | - Stephen N Atkinson
- Wildlife Research Section, Department of Environment, Government of Nunavut, Igloolik, NU, Canada
| | - Eric V Regehr
- Polar Science Center, Applied Physics Laboratory, University of Washington, Seattle, WA, USA
| | - Harry L Stern
- Polar Science Center, Applied Physics Laboratory, University of Washington, Seattle, WA, USA
| | - Erik W Born
- Greenland Institute of Natural Resources, Nuuk, Greenland
| | - Øystein Wiig
- Natural History Museum, University of Oslo, Oslo, Norway
| | - Nicholas J Lunn
- Environment and Climate Change Canada, University of Alberta, Edmonton, AB, Canada
| | - Markus Dyck
- Wildlife Research Section, Department of Environment, Government of Nunavut, Igloolik, NU, Canada
| | - Patrick Heagerty
- Department of Biostatistics, University of Washington, Seattle, WA, USA
| | - Benjamin R Cohen
- Polar Science Center, Applied Physics Laboratory, University of Washington, Seattle, WA, USA
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30
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Penk SR, Bodner K, Vargas Soto JS, Chenery ES, Nascou A, Molnár PK. Mechanistic models can reveal infection pathways from prevalence data: the mysterious case of polar bears
Ursus maritimus
and
Trichinella nativa. OIKOS 2020. [DOI: 10.1111/oik.07458] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Stephanie R. Penk
- Laboratory of Quantitative Global Change Ecology, Dept of Biological Sciences, Univ. of Toronto Scarborough 1265 Military Trail Scarborough ON M1C 1A4 Canada
- Dept of Ecology and Evolutionary Biology, Univ. of Toronto 25 Willcocks Street Toronto ON M5S 3B2 Canada
| | - Korryn Bodner
- Laboratory of Quantitative Global Change Ecology, Dept of Biological Sciences, Univ. of Toronto Scarborough 1265 Military Trail Scarborough ON M1C 1A4 Canada
- Dept of Ecology and Evolutionary Biology, Univ. of Toronto 25 Willcocks Street Toronto ON M5S 3B2 Canada
| | - Juan S. Vargas Soto
- Laboratory of Quantitative Global Change Ecology, Dept of Biological Sciences, Univ. of Toronto Scarborough 1265 Military Trail Scarborough ON M1C 1A4 Canada
- Dept of Ecology and Evolutionary Biology, Univ. of Toronto 25 Willcocks Street Toronto ON M5S 3B2 Canada
| | - Emily S. Chenery
- Laboratory of Quantitative Global Change Ecology, Dept of Biological Sciences, Univ. of Toronto Scarborough 1265 Military Trail Scarborough ON M1C 1A4 Canada
- Dept of Ecology and Evolutionary Biology, Univ. of Toronto 25 Willcocks Street Toronto ON M5S 3B2 Canada
| | - Alexander Nascou
- Laboratory of Quantitative Global Change Ecology, Dept of Biological Sciences, Univ. of Toronto Scarborough 1265 Military Trail Scarborough ON M1C 1A4 Canada
- Dept of Ecology and Evolutionary Biology, Univ. of Toronto 25 Willcocks Street Toronto ON M5S 3B2 Canada
| | - Péter K. Molnár
- Laboratory of Quantitative Global Change Ecology, Dept of Biological Sciences, Univ. of Toronto Scarborough 1265 Military Trail Scarborough ON M1C 1A4 Canada
- Dept of Ecology and Evolutionary Biology, Univ. of Toronto 25 Willcocks Street Toronto ON M5S 3B2 Canada
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31
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Teitelbaum CS, Altizer S, Hall RJ. Movement rules determine nomadic species' responses to resource supplementation and degradation. J Anim Ecol 2020; 89:2644-2656. [PMID: 32783225 DOI: 10.1111/1365-2656.13318] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Accepted: 07/27/2020] [Indexed: 11/29/2022]
Abstract
In environments that vary unpredictably, many animals are nomadic, moving in an irregular pattern that differs from year to year. Exploring the mechanisms of nomadic movement is needed to understand how animals survive in highly variable environments, and to predict behavioural and population responses to environmental change. We developed a network model to identify plausible mechanisms of nomadic animal movement by comparing the performance of multiple movement rules along a continuum from nomadism to residency. Using simulations and analytical results, we explored how different types of habitat modifications (that augment or decrease resource availability) might affect the abundance and movement rates of animals following each of these rules. Movement rules for which departure from patches depended on resource availability and/or competition performed almost equally well and better than residency or uninformed movement under most conditions, even though animals using each rule moved at substantially different rates. Habitat modifications that stabilized resources, either by resource supplementation or degradation, eroded the benefits of informed nomadic movements, particularly for movements based on resource availability alone. These results suggest that simple movement rules can explain nomadic animal movements and determine species' responses to environmental change. In particular, landscape stabilization and supplementation might be useful strategies for promoting populations of resident animals, but would be less beneficial for managing highly mobile species, many of which are threatened by habitat disruption and changes in climate.
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Affiliation(s)
| | - Sonia Altizer
- Odum School of Ecology, University of Georgia, Athens, GA, USA
| | - Richard J Hall
- Odum School of Ecology, University of Georgia, Athens, GA, USA.,Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA, USA
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32
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Florko KRN, Thiemann GW, Bromaghin JF. Drivers and consequences of apex predator diet composition in the Canadian Beaufort Sea. Oecologia 2020; 194:51-63. [PMID: 32897468 DOI: 10.1007/s00442-020-04747-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Accepted: 08/28/2020] [Indexed: 10/23/2022]
Abstract
Polar bears (Ursus maritimus) rely on annual sea ice as their primary habitat for hunting marine mammal prey. Given their long lifespan, wide geographic distribution, and position at the top of the Arctic marine food web, the diet composition of polar bears can provide insights into temporal and spatial ecosystem dynamics related to climate-mediated sea ice loss. Polar bears with the greatest ecological constraints on diet composition may be most vulnerable to climate-related changes in ice conditions and prey availability. We used quantitative fatty acid signature analysis (QFASA) to estimate the diets of polar bears (n = 419) in two western Canadian Arctic subpopulations (Northern Beaufort Sea and Southern Beaufort Sea) from 1999 to 2015. Polar bear diets were dominated by ringed seal (Pusa hispida), with interannual, seasonal, age- and sex-specific variation. Foraging area and sea ice conditions also affected polar bear diet composition. Most variation in bear diet was explained by longitude, reflecting spatial variation in prey availability. Sea ice conditions (extent, thickness, and seasonal duration) declined throughout the study period, and date of sea ice break-up in the preceding spring was positively correlated with female body condition and consumption of beluga whale (Delphinapterus leucas), suggesting that bears foraged on beluga whales during entrapment events. Female body condition was positively correlated with ringed seal consumption, and negatively correlated with bearded seal consumption. This study provides insights into the complex relationships between declining sea ice habitat and the diet composition and foraging success of a wide-ranging apex predator.
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Affiliation(s)
- Katie R N Florko
- Department of Biology, York University, 4700 Keele Street, Toronto, ON, M3J 1P3, Canada.
| | - Gregory W Thiemann
- Faculty of Environmental Studies, York University, 4700 Keele Street, Toronto, ON, M3J 1P3, Canada
| | - Jeffrey F Bromaghin
- Alaska Science Center, U.S. Geological Survey, 4210 University Drive, Anchorage, AK, 99508, USA
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33
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Rode KD, Atwood TC, Thiemann GW, St. Martin M, Wilson RR, Durner GM, Regehr EV, Talbot SL, Sage GK, Pagano AM, Simac KS. Identifying reliable indicators of fitness in polar bears. PLoS One 2020; 15:e0237444. [PMID: 32813753 PMCID: PMC7437918 DOI: 10.1371/journal.pone.0237444] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Accepted: 07/27/2020] [Indexed: 01/08/2023] Open
Abstract
Animal structural body size and condition are often measured to evaluate individual health, identify responses to environmental change and food availability, and relate food availability to effects on reproduction and survival. A variety of condition metrics have been developed but relationships between these metrics and vital rates are rarely validated. Identifying an optimal approach to estimate the body condition of polar bears is needed to improve monitoring of their response to decline in sea ice habitat. Therefore, we examined relationships between several commonly used condition indices (CI), body mass, and size with female reproductive success and cub survival among polar bears (Ursus maritimus) measured in two subpopulations over three decades. To improve measurement and application of morphometrics and CIs, we also examined whether CIs are independent of age and structural size–an important assumption for monitoring temporal trends—and factors affecting measurement precision and accuracy. Maternal CIs and mass measured the fall prior to denning were related to cub production. Similarly, maternal CIs, mass, and length were related to the mass of cubs or yearlings that accompanied her. However, maternal body mass, but not CIs, measured in the spring was related to cub production and only maternal mass and length were related to the probability of cub survival. These results suggest that CIs may not be better indicators of fitness than body mass in part because CIs remove variation associated with body size that is important in affecting fitness. Further, CIs exhibited variable relationships with age for growing bears and were lower for longer bears despite body length being related to cub survival and female reproductive success. These results are consistent with findings from other species indicating that body mass is a useful metric to link environmental conditions and population dynamics.
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Affiliation(s)
- Karyn D. Rode
- U.S. Geological Survey, Alaska Science Center, Anchorage, Alaska, United States of America
- * E-mail:
| | - Todd C. Atwood
- U.S. Geological Survey, Alaska Science Center, Anchorage, Alaska, United States of America
| | | | - Michelle St. Martin
- U.S. Fish and Wildlife Service, Marine Mammals Management, Anchorage, Alaska, United States of America
| | - Ryan R. Wilson
- U.S. Fish and Wildlife Service, Marine Mammals Management, Anchorage, Alaska, United States of America
| | - George M. Durner
- U.S. Geological Survey, Alaska Science Center, Anchorage, Alaska, United States of America
| | - Eric V. Regehr
- University of Washington, Polar Science Center, Seattle, Washington, United States of America
| | - Sandra L. Talbot
- U.S. Geological Survey, Alaska Science Center, Anchorage, Alaska, United States of America
| | - George K. Sage
- U.S. Geological Survey, Alaska Science Center, Anchorage, Alaska, United States of America
| | - Anthony M. Pagano
- U.S. Geological Survey, Alaska Science Center, Anchorage, Alaska, United States of America
| | - Kristin S. Simac
- U.S. Geological Survey, Alaska Science Center, Anchorage, Alaska, United States of America
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34
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35
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Mangipane LS, Lafferty DJR, Joly K, Sorum MS, Cameron MD, Belant JL, Hilderbrand GV, Gustine DD. Dietary plasticity and the importance of salmon to brown bear (Ursus arctos) body size and condition in a low Arctic ecosystem. Polar Biol 2020. [DOI: 10.1007/s00300-020-02690-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
AbstractEcological flexibility within animal populations can allow for variation in resource use and foraging decisions. We estimated brown bear (Ursus arctos) diet composition in Gates of the Arctic National Park and Preserve, Alaska from 2013 to 2015 to evaluate how variation in foraging behavior influences body condition and size. We used stable carbon (δ13C) and nitrogen (δ15N) isotope analyses of sectioned brown bear hair samples to evaluate assimilated diet. We then developed a set of a priori linear models to evaluate differences in the diet composition of brown bears (n = 80) in relation to body fat (%) and mass. The proportion of meat (salmon [Oncorhynchus keta] and terrestrial meat combined) in the diet from July through late September varied between male and female bears, with males ($$\stackrel{-}{x}$$
x
-
= 62%, SD = 30) assimilating significantly more meat than females ($$\stackrel{-}{x}$$
x
-
= 40%, SD = 29). Most of the meat consumed came from marine-derived resources for males (53% of the total diet or 86% of the meat) and females (31% of the total diet or 77% of the meat). As we found the range of observed diets was unrelated to physiological outcomes (i.e., percentage body fat), we suggest that ecological flexibility within populations may provide an adaptive advantage by allowing individuals to reduce competition with conspecifics by foraging on alternate food resources. Identifying variable foraging behaviors within a population can allow for a better understanding of complex behaviors and, ultimately, lead to more informed management decisions related to habitat use, development, and harvest.
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36
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Laidre KL, Atkinson S, Regehr EV, Stern HL, Born EW, Wiig Ø, Lunn NJ, Dyck M. Interrelated ecological impacts of climate change on an apex predator. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2020; 30:e02071. [PMID: 31925853 PMCID: PMC7317597 DOI: 10.1002/eap.2071] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Revised: 09/12/2019] [Accepted: 11/11/2019] [Indexed: 05/29/2023]
Abstract
Climate change has broad ecological implications for species that rely on sensitive habitats. For some top predators, loss of habitat is expected to lead to cascading behavioral, nutritional, and reproductive changes that ultimately accelerate population declines. In the case of the polar bear (Ursus maritimus), declining Arctic sea ice reduces access to prey and lengthens seasonal fasting periods. We used a novel combination of physical capture, biopsy darting, and visual aerial observation data to project reproductive performance for polar bears by linking sea ice loss to changes in habitat use, body condition (i.e., fatness), and cub production. Satellite telemetry data from 43 (1991-1997) and 38 (2009-2015) adult female polar bears in the Baffin Bay subpopulation showed that bears now spend an additional 30 d on land (90 d in total) in the 2000s compared to the 1990s, a change closely correlated with changes in spring sea ice breakup and fall sea ice formation. Body condition declined for all sex, age, and reproductive classes and was positively correlated with sea ice availability in the current and previous year. Furthermore, cub litter size was positively correlated with maternal condition and spring breakup date (i.e., later breakup leading to larger litters), and negatively correlated with the duration of the ice-free period (i.e., longer ice-free periods leading to smaller litters). Based on these relationships, we projected reproductive performance three polar bear generations into the future (approximately 35 yr). Results indicate that two-cub litters, previously the norm, could largely disappear from Baffin Bay as sea ice loss continues. Our findings demonstrate how concurrent analysis of multiple data types collected over long periods from polar bears can provide a mechanistic understanding of the ecological implications of climate change. This information is needed for long-term conservation planning, which includes quantitative harvest risk assessments that incorporate estimated or assumed trends in future environmental carrying capacity.
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Affiliation(s)
- Kristin L. Laidre
- Polar Science CenterApplied Physics LaboratoryUniversity of WashingtonSeattleWashington98105USA
| | - Stephen Atkinson
- Wildlife Research SectionDepartment of EnvironmentGovernment of NunavutP.O. Box 209IgloolikNunavutX0A 0L0Canada
| | - Eric V. Regehr
- Polar Science CenterApplied Physics LaboratoryUniversity of WashingtonSeattleWashington98105USA
| | - Harry L. Stern
- Polar Science CenterApplied Physics LaboratoryUniversity of WashingtonSeattleWashington98105USA
| | - Erik W. Born
- Greenland Institute of Natural ResourcesP.O. Box 5703900NuukGreenland
| | - Øystein Wiig
- Natural History MuseumUniversity of OsloP.O. Box 1172BlindernN‐0318OsloNorway
| | - Nicholas J. Lunn
- Environment and Climate Change CanadaCW‐422 Biological Sciences BuildingUniversity of AlbertaEdmontonAlbertaT6G 2E9Canada
| | - Markus Dyck
- Wildlife Research SectionDepartment of EnvironmentGovernment of NunavutP.O. Box 209IgloolikNunavutX0A 0L0Canada
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37
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Jensen EL, Tschritter C, de Groot PVC, Hayward KM, Branigan M, Dyck M, Clemente‐Carvalho RBG, Lougheed SC. Canadian polar bear population structure using genome-wide markers. Ecol Evol 2020; 10:3706-3714. [PMID: 32313629 PMCID: PMC7160183 DOI: 10.1002/ece3.6159] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Revised: 01/23/2020] [Accepted: 02/18/2020] [Indexed: 12/01/2022] Open
Abstract
Predicting the consequences of environmental changes, including human-mediated climate change on species, requires that we quantify range-wide patterns of genetic diversity and identify the ecological, environmental, and historical factors that have contributed to it. Here, we generate baseline data on polar bear population structure across most Canadian subpopulations (n = 358) using 13,488 genome-wide single nucleotide polymorphisms (SNPs) identified with double-digest restriction site-associated DNA sequencing (ddRAD). Our ddRAD dataset showed three genetic clusters in the sampled Canadian range, congruent with previous studies based on microsatellites across the same regions; however, due to a lack of sampling in Norwegian Bay, we were unable to confirm the existence of a unique cluster in that subpopulation. These data on the genetic structure of polar bears using SNPs provide a detailed baseline against which future shifts in population structure can be assessed, and opportunities to develop new noninvasive tools for monitoring polar bears across their range.
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Affiliation(s)
- Evelyn L. Jensen
- Department of BiologyQueen’s UniversityKingstonONCanada
- Present address:
Department of Ecology and Evolutionary BiologyYale UniversityNew HavenCTUSA
| | | | | | | | - Marsha Branigan
- Department of Environment and Natural ResourcesGovernment of the Northwest TerritoriesInuvikNTCanada
| | - Markus Dyck
- Department of EnvironmentGovernment of NunavutIgloolikNUCanada
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38
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Foraging behaviour of the South American sea lion (Otaria byronia) in two disparate ecosystems assessed through blubber fatty acid analysis. Sci Rep 2020; 10:5725. [PMID: 32235837 PMCID: PMC7109089 DOI: 10.1038/s41598-020-62178-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2019] [Accepted: 02/14/2020] [Indexed: 11/08/2022] Open
Abstract
Fatty acids have been widely used as trophic biomarkers in marine mammals. However, for the South American sea lion, the most abundant otariid in the eastern South Pacific, there is no information about blubber fatty acids and their link to diet. Here, we compare fatty acid profiles of sea lions from two distinct oceanographic regions in northern and southern Chile. Their fatty acids vary greatly between regions, suggesting dietary differences at a spatial scale. The fatty acid C22:6ω3 was more abundant in sea lions from the northern region, likely associated with consumption of anchovy, cephalopods, and crustaceans, which are rich in that fatty acid, and have been reported as their main prey items. Sea lions from the southern region were richer in C22:1 and C20:1, characteristic of teleost fish, suggesting a piscivorous diet. Males displayed a more diverse fatty acid composition than females, suggesting a wider trophic niche. Few individual sea lions within the southern region had unusually high levels of C18:2ω6, commonly found in terrestrial environments. This suggests consumption of farmed salmon, whose diet is usually based on terrestrial sources. This demonstrates how human intervention is being reflected in the tissues of a top predator in a natural environment.
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39
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Pagano AM, Atwood TC, Durner GM, Williams TM. The seasonal energetic landscape of an apex marine carnivore, the polar bear. Ecology 2020; 101:e02959. [DOI: 10.1002/ecy.2959] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Revised: 10/22/2019] [Accepted: 11/12/2019] [Indexed: 12/12/2022]
Affiliation(s)
- Anthony M. Pagano
- U.S. Geological SurveyAlaska Science Center4210 University Drive Anchorage Alaska99508USA
- Department of Ecology & Evolutionary Biology University of California Santa Cruz 130 McAllister Way Santa Cruz California95060USA
| | - Todd C. Atwood
- U.S. Geological SurveyAlaska Science Center4210 University Drive Anchorage Alaska99508USA
| | - George M. Durner
- U.S. Geological SurveyAlaska Science Center4210 University Drive Anchorage Alaska99508USA
| | - Terrie M. Williams
- Department of Ecology & Evolutionary Biology University of California Santa Cruz 130 McAllister Way Santa Cruz California95060USA
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Galicia MP, Thiemann GW, Dyck MG. Correlates of seasonal change in the body condition of an Arctic top predator. GLOBAL CHANGE BIOLOGY 2020; 26:840-850. [PMID: 31465583 DOI: 10.1111/gcb.14817] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Accepted: 07/26/2019] [Indexed: 06/10/2023]
Abstract
Climate-driven sea ice loss has led to changes in the timing of key biological events in the Arctic, however, the consequences and rate of these changes remain largely unknown. Polar bears (Ursus maritimus) undergo seasonal changes in energy stores in relation to foraging opportunities and habitat conditions. Declining sea ice has been linked to reduced body condition in some subpopulations, however, the specific timing and duration of the feeding period when bears acquire most of their energy stores and its relationship to the timing of ice break-up is poorly understood. We used community-based sampling to investigate seasonality in body condition (energy stores) of polar bears in Nunavut, Canada, and examined the influence of sea ice variables. We used adipose tissue lipid content as an index of body condition for 1,206 polar bears harvested from 2010-2017 across five subpopulations with varying seasonal ice conditions: Baffin Bay (October-August), Davis Strait and Foxe Basin (year-round), Gulf of Boothia and Lancaster Sound (August-May). Similar seasonal patterns were found in body condition across subpopulations with bears at their nadir of condition in the spring, followed by fat accumulation past break-up date and subsequent peak body condition in autumn, indicating that bears are actively foraging in late spring and early summer. Late season feeding implies that even minor advances in the timing of break-up may have detrimental effects on foraging opportunities, body condition, and subsequent reproduction and survival. The magnitude of seasonal changes in body condition varied across the study area, presumably driven by local environmental conditions. Our results demonstrate how community-based monitoring of polar bears can reveal population-level responses to climate warming in advance of detectable demographic change. Our data on the seasonal timing of polar bear foraging and energy storage should inform predictive models of the effects of climate-mediated sea ice loss.
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Affiliation(s)
| | | | - Markus G Dyck
- Wildlife Research Station, Department of Environment, Government of Nunavut, Igloolik, NU, Canada
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Scharf HR, Hooten MB, Wilson RR, Durner GM, Atwood TC. Accounting for phenology in the analysis of animal movement. Biometrics 2019; 75:810-820. [PMID: 30859552 DOI: 10.1111/biom.13052] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2018] [Accepted: 02/26/2019] [Indexed: 11/29/2022]
Abstract
The analysis of animal tracking data provides important scientific understanding and discovery in ecology. Observations of animal trajectories using telemetry devices provide researchers with information about the way animals interact with their environment and each other. For many species, specific geographical features in the landscape can have a strong effect on behavior. Such features may correspond to a single point (eg, dens or kill sites), or to higher dimensional subspaces (eg, rivers or lakes). Features may be relatively static in time (eg, coastlines or home-range centers), or may be dynamic (eg, sea ice extent or areas of high-quality forage for herbivores). We introduce a novel model for animal movement that incorporates active selection for dynamic features in a landscape. Our approach is motivated by the study of polar bear (Ursus maritimus) movement. During the sea ice melt season, polar bears spend much of their time on sea ice above shallow, biologically productive water where they hunt seals. The changing distribution and characteristics of sea ice throughout the year mean that the location of valuable habitat is constantly shifting. We develop a model for the movement of polar bears that accounts for the effect of this important landscape feature. We introduce a two-stage procedure for approximate Bayesian inference that allows us to analyze over 300 000 observed locations of 186 polar bears from 2012 to 2016. We use our model to estimate a spatial boundary of interest to wildlife managers that separates two subpopulations of polar bears from the Beaufort and Chukchi seas.
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Affiliation(s)
- Henry R Scharf
- Department of Statistics, Colorado State University, Fort Collins, Colorado
| | - Mevin B Hooten
- Department of Statistics, Colorado State University, Fort Collins, Colorado.,Department of Fish, Wildlife, and Conservation Biology, Colorado Cooperative Fish and Wildlife Research Unit, U.S. Geological Survey, Fort Collins, Colorado
| | - Ryan R Wilson
- Marine Mammals Management, U.S. Fish and Wildlife Service, Anchorage, Alaska
| | - George M Durner
- Alaska Science Center, U.S. Geological Survey, Anchorage, Alaska
| | - Todd C Atwood
- Alaska Science Center, U.S. Geological Survey, Anchorage, Alaska
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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. ENVIRONMENTAL SCIENCE & TECHNOLOGY 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] [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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Fry TL, Friedrichs KR, Atwood TC, Duncan C, Simac K, Goldberg T. Reference intervals for blood-based biochemical analytes of southern Beaufort Sea polar bears. CONSERVATION PHYSIOLOGY 2019; 7:coz040. [PMID: 31548889 PMCID: PMC6748785 DOI: 10.1093/conphys/coz040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Revised: 05/09/2019] [Accepted: 06/10/2019] [Indexed: 05/14/2023]
Abstract
Accurate reference intervals (RIs) for commonly measured blood-based analytes are essential for health monitoring programmes. Baseline values for a panel of analytes can be used to monitor physiologic and pathophysiologic processes such as organ function, electrolyte balance and protein catabolism. Our reference population includes 651 serum samples from polar bears (Ursus maritimus) from the southern Beaufort Sea (SB) subpopulation sampled in Alaska, USA, between 1983 and 2016. To establish RI for 13 biochemical analytes, we defined specific criteria for characterizing the reference population and relevant subgroups. To account for differences in seasonal life history characteristics, we determined separate RI for the spring and fall seasons, when prey availability and energetic requirements of bears differ. We established RI for five subgroups in spring based on sex, age class and denning status, and three subgroups in fall based on sex and age class in females only. Alkaline phosphatase activities were twice as high in subadult as in adult polar bears in spring (z males = 4.08, P males < 0.001, z females = 3.90, P females < 0.001) and did not differ between seasons. Denning females had significantly higher glucose concentrations than non-denning females (z = 4.94, P < 0.001), possibly reflecting differences in energy expenditure during lactation. A total of 10 of the 13 analytes differed significantly between seasons in either males or females; however, the physiologic importance of these differences may be minimal. Establishing these RIs allows for temporal monitoring of polar bear health in the SB and may prove useful for assessing and monitoring additional polar bear subpopulations in a changing Arctic environment.
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Affiliation(s)
- Tricia L Fry
- Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin, Madison, USA
- Corresponding author: Hanson Laboratories, University of Wisconsin–Madison, 1656 Linden Drive, Madison, Wisconsin 53706, USA. Tel: 608-448-5181.
| | - Kristen R Friedrichs
- Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin, Madison, USA
| | - Todd C Atwood
- Alaska Science Center, US Geological Survey, Anchorage, AK, USA
| | - Colleen Duncan
- Department of Microbiology, Immunology and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO, USA
| | - Kristin Simac
- Alaska Science Center, US Geological Survey, Anchorage, AK, USA
| | - Tony Goldberg
- Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin, Madison, USA
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Regehr EV, Hostetter NJ, Wilson RR, Rode KD, Martin MS, Converse SJ. Integrated Population Modeling Provides the First Empirical Estimates of Vital Rates and Abundance for Polar Bears in the Chukchi Sea. Sci Rep 2018; 8:16780. [PMID: 30429493 PMCID: PMC6235872 DOI: 10.1038/s41598-018-34824-7] [Citation(s) in RCA: 69] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Accepted: 10/22/2018] [Indexed: 12/27/2022] Open
Abstract
Large carnivores are imperiled globally, and characteristics making them vulnerable to extinction (e.g., low densities and expansive ranges) also make it difficult to estimate demographic parameters needed for management. Here we develop an integrated population model to analyze capture-recapture, radiotelemetry, and count data for the Chukchi Sea subpopulation of polar bears (Ursus maritimus), 2008-2016. Our model addressed several challenges in capture-recapture studies for polar bears by including a multievent structure reflecting location and life history states, while accommodating state uncertainty. Female breeding probability was 0.83 (95% credible interval [CRI] = 0.71-0.90), with litter sizes of 2.18 (95% CRI = 1.71-2.82) for age-zero and 1.61 (95% CRI = 1.46-1.80) for age-one cubs. Total adult survival was 0.90 (95% CRI = 0.86-0.92) for females and 0.89 (95% CRI = 0.83-0.93) for males. Spring on-ice densities west of Alaska were 0.0030 bears/km2 (95% CRI = 0.0016-0.0060), similar to 1980s-era density estimates although methodological differences complicate comparison. Abundance of the Chukchi Sea subpopulation, derived by extrapolating density from the study area using a spatially-explicit habitat metric, was 2,937 bears (95% CRI = 1,552-5,944). Our findings are consistent with other lines of evidence suggesting the Chukchi Sea subpopulation has been productive in recent years, although it is uncertain how long this will continue given sea-ice loss due to climate change.
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Affiliation(s)
- Eric V Regehr
- Marine Mammals Management, U.S. Fish and Wildlife Service, Anchorage, AK, USA.
- Polar Science Center, University of Washington, Seattle, WA, USA.
| | - Nathan J Hostetter
- U.S. Geological Survey, Patuxent Wildlife Research Center, Laurel, MD, USA
| | - Ryan R Wilson
- Marine Mammals Management, U.S. Fish and Wildlife Service, Anchorage, AK, USA
| | - Karyn D Rode
- U.S. Geological Survey, Alaska Science Center, Anchorage, AK, USA
| | - Michelle St Martin
- Marine Mammals Management, U.S. Fish and Wildlife Service, Anchorage, AK, USA
| | - Sarah J Converse
- U.S. Geological Survey, Washington Cooperative Fish and Wildlife Research Unit, School of Environmental and Forest Sciences (SEFS) & School of Aquatic and Fishery Sciences (SAFS), University of Washington, Seattle, WA, USA
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45
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Estimating the abundance of polar bears on Wrangel Island during late summer using high-resolution satellite imagery: a pilot study. Polar Biol 2018. [DOI: 10.1007/s00300-018-2384-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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46
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Hamilton SG, Derocher AE. Assessment of global polar bear abundance and vulnerability. Anim Conserv 2018. [DOI: 10.1111/acv.12439] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- S. G. Hamilton
- Department of Biological Sciences University of Alberta Edmonton AB Canada
| | - A. E. Derocher
- Department of Biological Sciences University of Alberta Edmonton AB Canada
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47
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Laidre KL, Stern H, Born EW, Heagerty P, Atkinson S, Wiig Ø, Lunn NJ, Regehr EV, McGovern R, Dyck M. Changes in winter and spring resource selection by polar bears Ursus maritimus in Baffin Bay over two decades of sea-ice loss. ENDANGER SPECIES RES 2018. [DOI: 10.3354/esr00886] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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48
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Florko KRN, Bernhardt W, Breiter CJC, Ferguson SH, Hainstock M, Young BG, Petersen SD. Decreasing sea ice conditions in western Hudson Bay and an increase in abundance of harbour seals (Phoca vitulina) in the Churchill River. Polar Biol 2018. [DOI: 10.1007/s00300-018-2277-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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49
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Hilderbrand GV, Gustine DD, Mangipane BA, Joly K, Leacock W, Mangipane LS, Erlenbach J, Sorum MS, Cameron MD, Belant JL, Cambier T. Body size and lean mass of brown bears across and within four diverse ecosystems. J Zool (1987) 2018. [DOI: 10.1111/jzo.12536] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
| | - D. D. Gustine
- Grand Teton National Park National Park Service Moose WY USA
| | - B. A. Mangipane
- Lake Clark National Park and Preserve National Park ServicePort Alsworth AK USA
| | - K. Joly
- Gates of the Arctic National Park and PreserveNational Park Service Fairbanks AK USA
| | - W. Leacock
- US Fish and Wildlife Service Kodiak National Wildlife Refuge KodiakAK USA
| | - L. S. Mangipane
- Carnivore Ecology Laboratory Forest and Wildlife Research Center Mississippi State University Mississippi State MS USA
| | - J. Erlenbach
- Department of Zoology Washington State University Pullman WAUSA
| | - M. S. Sorum
- Gates of the Arctic National Park and PreserveNational Park Service Fairbanks AK USA
| | - M. D. Cameron
- Gates of the Arctic National Park and PreserveNational Park Service Fairbanks AK USA
| | - J. L. Belant
- Carnivore Ecology Laboratory Forest and Wildlife Research Center Mississippi State University Mississippi State MS USA
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50
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Affiliation(s)
- John P Whiteman
- Department of Biology, University of New Mexico, Albuquerque, NM 87131, USA.
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