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Mikkelsen AJ, Hobson KA, Sergiel A, Hertel AG, Selva N, Zedrosser A. Testing foraging optimization models in brown bears: Time for a paradigm shift in nutritional ecology? Ecology 2024; 105:e4228. [PMID: 38071743 DOI: 10.1002/ecy.4228] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Accepted: 10/30/2023] [Indexed: 12/31/2023]
Abstract
How organisms obtain energy to survive and reproduce is fundamental to ecology, yet researchers use theoretical concepts represented by simplified models to estimate diet and predict community interactions. Such simplistic models can sometimes limit our understanding of ecological principles. We used a polyphagous species with a wide distribution, the brown bear (Ursus arctos), to illustrate how disparate theoretical frameworks in ecology can affect conclusions regarding ecological communities. We used stable isotope measurements (δ13 C, δ15 N) from hairs of individually monitored bears in Sweden and Bayesian mixing models to estimate dietary proportions of ants, moose, and three berry species to compare with other brown bear populations. We also developed three hypotheses based on predominant foraging literature, and then compared predicted diets to field estimates. Our three models assumed (1) bears forage to optimize caloric efficiency (optimum foraging model), predicting bears predominately eat berries (~70% of diet) and opportunistically feed on moose (Alces alces) and ants (Formica spp. and Camponotus spp; ~15% each); (2) bears maximize meat intake (maximizing fitness model), predicting a diet of 35%-50% moose, followed by ants (~30%), and berries (~15%); (3) bears forage to optimize macronutrient balance (macronutrient model), predicting a diet of ~22% (dry weight) or 17% metabolizable energy from proteins, with the rest made up of carbohydrates and lipids (~49% and 29% dry matter or 53% and 30% metabolizable energy, respectively). Bears primarily consumed bilberries (Vaccinium myrtillus; 50%-55%), followed by lingonberries (V. vitis-idaea; 22%-30%), crowberries (Empetrum nigrum; 8%-15%), ants (5%-8%), and moose (3%-4%). Dry matter dietary protein was lower than predicted by the maximizing fitness model and the macronutrient balancing model, but protein made up a larger proportion of the metabolizable energy than predicted. While diets most closely resembled predictions from optimal foraging theory, none of the foraging hypotheses fully described the relationship between foraging and ecological niches in brown bears. Acknowledging and broadening models based on foraging theories is more likely to foster novel discoveries and insights into the role of polyphagous species in ecosystems and we encourage this approach.
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Affiliation(s)
- Ashlee J Mikkelsen
- Department of Natural Sciences and Environmental Health, University of South-Eastern Norway, Bø, Norway
| | - Keith A Hobson
- Environment and Climate Change Canada, Saskatoon, Saskatchewan, Canada
- Department of Biology, University of Western Ontario, London, Ontario, Canada
| | - Agnieszka Sergiel
- Institute of Nature Conservation, Polish Academy of Sciences, Krakow, Poland
| | - Anne G Hertel
- Department of Natural Sciences and Environmental Health, University of South-Eastern Norway, Bø, Norway
- Department of Biology, Ludwig Maximilians University of Munich, Planegg, Germany
| | - Nuria Selva
- Institute of Nature Conservation, Polish Academy of Sciences, Krakow, Poland
| | - Andreas Zedrosser
- Department of Natural Sciences and Environmental Health, University of South-Eastern Norway, Bø, Norway
- Department of Integrative Biology, University of Natural Recourses and Applied Life Sciences, Vienna, Austria
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Abstract
The measurement of naturally occurring stable isotope ratios of the light elements (C, N, H, O, S) in animal tissues and associated organic and inorganic fractions of associated environments holds immense potential as a means of addressing effects of global change on animals. This paper provides a brief review of studies that have used the isotope approach to evaluate changes in diet, isotopic niche, contaminant burden, reproductive and nutritional investment, invasive species and shifts in migration origin or destination with clear links to evaluating effects of global change. This field has now reached a level of maturity that is impressive but generally underappreciated and involves technical as well as statistical advances and access to freely available R-based packages. There is a need for animal ecologists and conservationists to design tissue collection networks that will best answer current and anticipated questions related to the global change and the biodiversity crisis. These developments will move the field of stable isotope ecology toward a more hypothesis driven discipline related to rapidly changing global events.
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Affiliation(s)
- Keith A Hobson
- Wildlife Research Division, Environment and Climate Change Canada, Saskatoon, SK, S7N 0X4, Canada.
- Department of Biology, Western University, London, ON, N6A 5B7, Canada.
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McCue MD. CO 2 scrubbing, zero gases, Keeling plots, and a mathematical approach to ameliorate the deleterious effects of ambient CO 2 during 13 C breath testing in humans and animals. Rapid Commun Mass Spectrom 2023; 37:e9639. [PMID: 37817343 DOI: 10.1002/rcm.9639] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2023] [Revised: 07/17/2023] [Accepted: 08/26/2023] [Indexed: 10/12/2023]
Abstract
13 C breath testing is increasingly used in physiology and ecology research because of what it reveals about the different fuels that animals oxidize to meet their energetic demands. Here I review the practice of 13 C breath testing in humans and other animals and describe the impact that contamination by ambient/background CO2 in the air can have on the accuracy of 13 C breath measurements. I briefly discuss physical methods to avoid sample contamination as well as the Keeling plot approach that researchers have been using for the past two decades to estimate δ13 C from breath samples mixed with ambient CO2 . Unfortunately, Keeling plots are not suited for 13 C breath testing in common situations where (1) a subject's VCO2 is dynamic, (2) ambient [CO2 ] may change, (3) a subject is sensitive to hypercapnia, or (4) in any flow-through indirect calorimetry system. As such, I present a mathematical solution that addresses these issues by using information about the instantaneous [CO2 ] and the δ13 CO2 of ambient air as well as the diluted breath sample to back-calculate the δ13 CO2 in the CO2 exhaled by the animal. I validate this approach by titrating a sample of 13 C-enriched gas into an air stream and demonstrate its ability to provide accurate values across a wide range of breath and air mixtures. This approach allows researchers to instantaneously calculate the δ13 C of exhaled gas of humans or other animals in real time without having to scrub ambient CO2 or rely on estimated values.
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Rode KD, Taras BD, Stricker CA, Atwood TC, Boucher NP, Durner GM, Derocher AE, Richardson ES, Cherry SG, Quakenbush L, Horstmann L, Bromaghin JF. Diet energy density estimated from isotopes in predator hair associated with survival, habitat, and population dynamics. Ecol Appl 2023; 33:e2751. [PMID: 36151883 DOI: 10.1002/eap.2751] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 07/29/2022] [Accepted: 08/30/2022] [Indexed: 06/16/2023]
Abstract
Sea ice loss is fundamentally altering the Arctic marine environment. Yet there is a paucity of data on the adaptability of food webs to ecosystem change, including predator-prey interactions. Polar bears (Ursus maritimus) are an important subsistence resource for Indigenous people and an apex predator that relies entirely on the under-ice food web to meet its energy needs. In this study, we assessed whether polar bears maintained dietary energy density by prey switching in response to spatiotemporal variation in prey availability. We compared the macronutrient composition of diets inferred from stable carbon and nitrogen isotopes in polar bear guard hair (primarily representing summer/fall diet) during periods when bears had low and high survival (2004-2016), between bears that summered on land versus pack ice, and between bears occupying different regions of the Alaskan and Canadian Beaufort Sea. Polar bears consumed diets with lower energy density during periods of low survival, suggesting that concurrent increased dietary proportions of beluga whales (Delphinapterus leucas) did not offset reduced proportions of ringed seals (Pusa hispida). Diets with the lowest energy density and proportions from ringed seal blubber were consumed by bears in the western Beaufort Sea (Alaska) during a period when polar bear abundance declined. Intake required to meet energy requirements of an average free-ranging adult female polar bear was 2.1 kg/day on diets consumed during years with high survival but rose to 3.0 kg/day when survival was low. Although bears that summered onshore in the Alaskan Beaufort Sea had higher-fat diets than bears that summered on the pack ice, access to the remains of subsistence-harvested bowhead whales (Balaena mysticetus) contributed little to improving diet energy density. Because most bears in this region remain with the sea ice year round, prey switching and consumption of whale carcasses onshore appear insufficient to augment diets when availability of their primary prey, ringed seals, is reduced. Our results show that a strong predator-prey relationship between polar bears and ringed seals continues in the Beaufort Sea. The method of estimating dietary blubber using predator hair, demonstrated here, provides a new metric to monitor predator-prey relationships that affect individual health and population demographics.
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Affiliation(s)
- Karyn D Rode
- U.S. Geological Survey, Alaska Science Center, Anchorage, Alaska, USA
| | - Brian D Taras
- Alaska Department of Fish and Game, Fairbanks, Alaska, USA
| | - Craig A Stricker
- U.S. Geological Survey, Fort Collins Science Center, Fort Collins, Colorado, USA
| | - Todd C Atwood
- U.S. Geological Survey, Alaska Science Center, Anchorage, Alaska, USA
| | - Nicole P Boucher
- University of Alberta, Edmonton, Alberta, Canada
- School of Environmental Studies, University of Victoria, Victoria, British Columbia, Canada
| | - George M Durner
- U.S. Geological Survey, Alaska Science Center, Anchorage, Alaska, USA
| | | | - Evan S Richardson
- Environment and Climate Change Canada, Science and Technology Branch, Winnipeg, Manitoba, Canada
| | - Seth G Cherry
- University of Alberta, Edmonton, Alberta, Canada
- Parks Canada, East Kootenay, British Columbia, Canada
| | | | - Lara Horstmann
- College of Fisheries and Ocean Sciences, University of Alaska Fairbanks, Fairbanks, Alaska, USA
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Abellan-Borja A, Rodriguez-Sanchez IP, Carrera-Treviño R, Villanueva-Segura OK, Zapata-Morin PA, Martinez-de-Villareal LE, Barboza-Aranda LJ, Gomez-Govea MA, Martinez-Fierro ML, Delgado-Enciso I, Ruiz-Ayma G, Gonzalez-Rojas JI, Guzman-Velasco A. Free amino acid and acylcarnitine values in Ursus americanus Pallas 1780 (black bear) from Northeastern Mexico. PLoS One 2023; 18:e0272979. [PMID: 36735654 PMCID: PMC9897576 DOI: 10.1371/journal.pone.0272979] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Accepted: 07/29/2022] [Indexed: 02/04/2023] Open
Abstract
INTRODUCTION Ursus americanus Pallas 1780 is the largest carnivore and the only ursid in Mexico. It is considered an endangered species in the country because its distribution and population have been reduced by up to 80% because of habitat loss or furtive hunting. These problems can lead to a diet change, which could result in metabolic disorders, such as fatty acid β-oxidation defects or organic acid metabolism disorders. In our study, a free amino acid and acylcarnitine profile was characterized. METHODS Peripheral blood samples were drawn from nine free-ranging black bears in a period of five months, from June to October of 2019 in Northeastern Mexico, and 12 amino acids and 30 acylcarnitines were determined and quantified. Age differences were observed in the samples through ANOVA and post-hoc Tukey test. RESULTS Only three metabolites showed a significant difference with age: alanine (Ala) [cubs vs juvenile], free-carnitine (C0) [juvenile vs cubs] and acetylcarnitine (C2) [cubs vs adults and juvenile vs cubs]. CONCLUSION Metabolites with variability due to age were identified, making them potential biomarkers to monitor metabolic status as early diagnosis in endangered species. This is the first study of black bear amino acid and acylcarnitine profiles, and the values found could be used as reference for free amino acid and acylcarnitine concentrations in further studies of the species.
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Affiliation(s)
- Andres Abellan-Borja
- Facultad de Ciencias Biológicas, Laboratorio de Fisiología Molecular y Estructural, Universidad Autonoma de Nuevo Leon, San Nicolas de los Garza, Mexico
| | - Iram P. Rodriguez-Sanchez
- Facultad de Ciencias Biológicas, Laboratorio de Fisiología Molecular y Estructural, Universidad Autonoma de Nuevo Leon, San Nicolas de los Garza, Mexico
| | - Rogelio Carrera-Treviño
- Facultad de Medicina Veterinaria y Zootecnia, Laboratorio de Vida Silvestre, Universidad Autonoma de Nuevo Leon, General Escobedo, Mexico
| | - Olga Karina Villanueva-Segura
- Facultad de Ciencias Biológicas, Laboratorio de Fisiología Molecular y Estructural, Universidad Autonoma de Nuevo Leon, San Nicolas de los Garza, Mexico
| | - Patricio Adrian Zapata-Morin
- Facultad de Ciencias Biológicas, Laboratorio de Fisiología Molecular y Estructural, Universidad Autonoma de Nuevo Leon, San Nicolas de los Garza, Mexico
| | | | - Luis Javier Barboza-Aranda
- Facultad de Medicina Veterinaria y Zootecnia, Laboratorio de Vida Silvestre, Universidad Autonoma de Nuevo Leon, General Escobedo, Mexico
| | - Mayra A. Gomez-Govea
- Facultad de Ciencias Biológicas, Laboratorio de Fisiología Molecular y Estructural, Universidad Autonoma de Nuevo Leon, San Nicolas de los Garza, Mexico
| | | | - Ivan Delgado-Enciso
- Universidad de Colima, Colima, Mexico
- Secretaria de Salud de Colima, Instituto Estatal de Cancer, Colima, Mexico
| | - Gabriel Ruiz-Ayma
- Facultad de Ciencias Biologicas, Laboratorio de Conservacion de Vida Silvestre y Desarrollo Sustentable, Universidad Autonoma de Nuevo Leon, San Nicolas de los Garza, Mexico
| | - Jose Ignacio Gonzalez-Rojas
- Facultad de Ciencias Biologicas, Laboratorio de Conservacion de Vida Silvestre y Desarrollo Sustentable, Universidad Autonoma de Nuevo Leon, San Nicolas de los Garza, Mexico
- * E-mail: (AGV); (JIGR)
| | - Antonio Guzman-Velasco
- Facultad de Ciencias Biologicas, Laboratorio de Conservacion de Vida Silvestre y Desarrollo Sustentable, Universidad Autonoma de Nuevo Leon, San Nicolas de los Garza, Mexico
- * E-mail: (AGV); (JIGR)
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Bonin M, Dussault C, Taillon J, Pisapio J, Lecomte N, Côté SD. Diet flexibility of wolves and black bears in the range of migratory caribou. J Mammal 2023. [DOI: 10.1093/jmammal/gyad002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Abstract
The diet of predators can be highly variable, which is exemplified by their ability to acclimate to a wide range of ecological conditions. Such flexibility in foraging may be a key aspect of their performance in unpredictable environments such as at the edge of the range of a species or where food availability varies greatly in time and space. Gaining information on the diets of predators under such conditions could foster our comprehension of their ecological flexibility and the potential role of predation on the population dynamics of prey. We determined the diet of wolves (Canis lupus) and black bears (Ursus americanus) in northern Québec and Labrador (Canada) within the range of two migratory caribou (Rangifer tarandus) herds: the high-abundance Rivière-aux-Feuilles herd (RFH) and low-abundance Rivière-George herd (RGH). Worldwide, decline in caribou populations has become a concern, stressing the need to better understand the factors involved in these declines, including predation. In northern Québec (RFH range), caribou was the primary year-round prey of wolves while moose (Alces alces) and muskoxen (Ovibos moschatus) were consumed in some sectors. The diet of wolves in northern Labrador (RGH range) varied seasonally, with caribou, moose, and fish as main prey during different periods throughout the year. Black bear diets varied seasonally and regionally. Among the foods we analyzed, caribou was the main source of animal protein for bears in northern Québec and northern Labrador, except during a high abundance of Ungava collared lemming (Dicrostonyx hudsonius). Only bears in northern Québec ate caribou during late summer/fall. Our results highlight the diet flexibility of wolves and black bears in northern food webs, and how their diets change in relation to the distribution and abundance of prey. Our results will help quantify the potential impact of these predators on prey populations in northern systems.
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Affiliation(s)
- Michaël Bonin
- Caribou Ungava, département de biologie, Université Laval , 1045 avenue de la Médecine, Québec City, Québec G1V 0A6 , Canada
- Centre d’études nordiques, Université Laval , 2405 rue de la Terrasse, Québec City, Québec G1V 0A6 , Canada
| | - Christian Dussault
- Caribou Ungava, département de biologie, Université Laval , 1045 avenue de la Médecine, Québec City, Québec G1V 0A6 , Canada
- Direction de l’expertise sur la faune terrestre, l’herpétofaune et l’avifaune, Ministère des Forêts, de la Faune et des Parcs du Québec, 880 chemin Sainte-Foy , Québec City, Québec G1S 4X4 , Canada
| | - Joëlle Taillon
- Caribou Ungava, département de biologie, Université Laval , 1045 avenue de la Médecine, Québec City, Québec G1V 0A6 , Canada
- Direction de l’expertise sur la faune terrestre, l’herpétofaune et l’avifaune, Ministère des Forêts, de la Faune et des Parcs du Québec, 880 chemin Sainte-Foy , Québec City, Québec G1S 4X4 , Canada
| | - John Pisapio
- Caribou Ungava, département de biologie, Université Laval , 1045 avenue de la Médecine, Québec City, Québec G1V 0A6 , Canada
- Wildlife Division, Newfoundland and Labrador Department of Fisheries, Forests and Agriculture , Happy Valley-Goose Bay, Newfoundland and Labrador A0P 1E0 , Canada
| | - Nicolas Lecomte
- Caribou Ungava, département de biologie, Université Laval , 1045 avenue de la Médecine, Québec City, Québec G1V 0A6 , Canada
- Centre d’études nordiques, Université Laval , 2405 rue de la Terrasse, Québec City, Québec G1V 0A6 , Canada
- Chaire de recherche du Canada en écologie polaire et boréale et Centre d’études nordiques, département de biologie, Université de Moncton , 18 avenue Antonine-Maillet, Moncton, New Brunswick E1A 3E9 , Canada
| | - Steeve D Côté
- Caribou Ungava, département de biologie, Université Laval , 1045 avenue de la Médecine, Québec City, Québec G1V 0A6 , Canada
- Centre d’études nordiques, Université Laval , 2405 rue de la Terrasse, Québec City, Québec G1V 0A6 , Canada
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Keogh MJ, Nicholson KL, Skinner JP. Relationships between age, diet, and stress-related hormones and reproduction in American marten ( Martes americana). J Mammal 2022. [DOI: 10.1093/jmammal/gyac067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Abstract
American marten (Martes americana) in Interior Alaska are at the northwestern limit of their North American range. To investigate factors that may be associated with reproduction we determined the cementum age and the presence or absence of blastocysts in 118 female martens for 3 years (2012, 2014, and 2016) in two regions. For each marten we collected fur samples and measured steroid hormone concentrations (cortisol, testosterone, and progesterone) and stable isotopes (δ15N and δ13C values, a proxy for diet). These parameters reflect the diet and endocrine activity between June and October when fur is grown. We also collected two claws from a subset of 39 female marten from one region in 2012 and 2014. Progesterone concentrations were measured in one whole claw and from a second claw divided into proximal (recent growth) and distal sections. Differences in the probability of blastocysts being present were associated with geographic region and sample year suggesting that reproduction in female marten varies on a fine scale. We found the that presence of blastocysts was positively associated with marten age and δ15N values in fur but negatively associated with fur cortisol concentrations. These findings suggest that the likelihood a female marten will reproduce in a given year is influenced, in part, by the proportion of protein in their diet and stressors encountered during late summer and fall, months before active gestation begins.
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Affiliation(s)
- Mandy J Keogh
- Division of Wildlife Conservation, Alaska Department of Fish and Game , Douglas, Alaska , USA
| | - Kerry L Nicholson
- Division of Wildlife Conservation, Alaska Department of Fish and Game , Fairbanks, Alaska , USA
| | - John P Skinner
- Division of Wildlife Conservation, Alaska Department of Fish and Game , Anchorage, Alaska , USA
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Lippold A, Boltunov A, Aars J, Andersen M, Blanchet MA, Dietz R, Eulaers I, Morshina TN, Sevastyanov VS, Welker JM, Routti H. Spatial variation in mercury concentrations in polar bear (Ursus maritimus) hair from the Norwegian and Russian Arctic. Sci Total Environ 2022; 822:153572. [PMID: 35121036 DOI: 10.1016/j.scitotenv.2022.153572] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 01/26/2022] [Accepted: 01/27/2022] [Indexed: 06/14/2023]
Abstract
We examined spatial variation in total mercury (THg) concentrations in 100 hair samples collected between 2008 and 2016 from 87 polar bears (Ursus maritimus) from the Norwegian (Svalbard Archipelago, western Barents Sea) and Russian Arctic (Kara Sea, Laptev Sea, and Chukchi Sea). We used latitude and longitude of home range centroid for the Norwegian bears and capture position for the Russian bears to account for the locality. We additionally examined hair stable isotope values of carbon (δ13C) and nitrogen (δ15N) to investigate feeding habits and their possible effect on THg concentrations. Median THg levels in polar bears from the Norwegian Arctic (1.99 μg g-1 dry weight) and the three Russian Arctic regions (1.33-1.75 μg g-1 dry weight) constituted about 25-50% of levels typically reported for the Greenlandic or North American populations. Total Hg concentrations in the Norwegian bears increased with intake of marine and higher trophic prey, while δ13C and δ15N did not explain variation in THg concentrations in the Russian bears. Total Hg levels were higher in northwest compared to southeast Svalbard. δ13C and δ15N values did not show any spatial pattern in the Norwegian Arctic. Total Hg concentrations adjusted for feeding ecology showed similar spatial trends as the measured concentrations. In contrast, within the Russian Arctic, THg levels were rather uniformly distributed, whereas δ13C values increased towards the east and south. The results indicate that Hg exposure in Norwegian and Russian polar bears is at the lower end of the pan-Arctic spectrum, and its spatial variation in the Norwegian and Russian Arctic is not driven by the feeding ecology of polar bears.
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Affiliation(s)
- Anna Lippold
- Norwegian Polar Institute, Fram Centre, Tromsø 9296, Norway
| | - Andrei Boltunov
- Marine Mammal Research and Expedition Centre, 36 Nahimovskiy pr., Moscow 117997, Russia
| | - Jon Aars
- Norwegian Polar Institute, Fram Centre, Tromsø 9296, Norway
| | | | - Marie-Anne Blanchet
- Norwegian Polar Institute, Fram Centre, Tromsø 9296, Norway; UiT The Arctic University of Norway, Tromsø 9019, Norway
| | - Rune Dietz
- Aarhus University, Institute of Ecoscience, Arctic Research Centre, Roskilde 4000, Denmark
| | - Igor Eulaers
- Norwegian Polar Institute, Fram Centre, Tromsø 9296, Norway; Aarhus University, Institute of Ecoscience, Arctic Research Centre, Roskilde 4000, Denmark
| | - Tamara N Morshina
- Research and Production Association "Typhoon", 249038 Obninsk, Kaluga Region, Russia
| | | | - Jeffrey M Welker
- University of Alaska Anchorage, Anchorage 99508, United States; University of Oulu, Oulu 90014, Finland; University of the Arctic, Rovaniemi 96460, Finland
| | - Heli Routti
- Norwegian Polar Institute, Fram Centre, Tromsø 9296, Norway.
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Chibowski P, Brzeziński M, Suska-Malawska M, Zub K. Diet/Hair and Diet/Faeces Trophic Discrimination Factors for Stable Carbon and Nitrogen Isotopes, and Hair Regrowth in the Yellow-Necked Mouse and Bank Vole. ANN ZOOL FENN 2022. [DOI: 10.5735/086.059.0115] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
Affiliation(s)
- Piotr Chibowski
- Faculty of Biology, Biological and Chemical Research Centre, University of Warsaw, Żwirki i Wigury 101, PL-02-089 Warsaw, Poland
| | - Marcin Brzeziński
- Faculty of Biology, Biological and Chemical Research Centre, University of Warsaw, Żwirki i Wigury 101, PL-02-089 Warsaw, Poland
| | - Małgorzata Suska-Malawska
- Faculty of Biology, Biological and Chemical Research Centre, University of Warsaw, Żwirki i Wigury 101, PL-02-089 Warsaw, Poland
| | - Karol Zub
- Mammal Research Institute, Polish Academy of Sciences, Stoczek 1, PL-17-230 Białowieża, Poland
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Stricker CA, Rode KD, Taras BD, Bromaghin JF, Horstmann L, Quakenbush L. Summer/fall diet and macronutrient assimilation in an Arctic predator. Oecologia 2022. [PMID: 35412091 DOI: 10.1007/s00442-022-05155-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [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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Javornik J, Šturm MB, Jerina K. Four approaches for estimating isotope discrimination factors produce contrasting dietary estimates for bears. URSUS 2021. [DOI: 10.2192/ursus-d-19-00028.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Affiliation(s)
- Jernej Javornik
- University of Ljubljana, Biotechnical faculty, Department of Forestry, Večna pot 83, 1000 Ljubljana, Slovenia
| | - Martina Burnik Šturm
- University of Natural Resources and Life Sciences (BOKU), Institute of Analytical Chemistry, Mutgasse 18, 1190 Vienna, Austria
| | - Klemen Jerina
- University of Ljubljana, Biotechnical faculty, Department of Forestry, Večna pot 83, 1000 Ljubljana, Slovenia
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Lamb AD, Lippi CA, Watkins‐Colwell GJ, Jones A, Warren DL, Iglesias TL, Brandley MC, Dornburg A. Comparing the dietary niche overlap and ecomorphological differences between invasive Hemidactylus mabouia geckos and a native gecko competitor. Ecol Evol 2021; 11:18719-18732. [PMID: 35003704 PMCID: PMC8717282 DOI: 10.1002/ece3.8401] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Revised: 10/06/2021] [Accepted: 10/12/2021] [Indexed: 12/31/2022] Open
Abstract
Hemidactylus mabouia is one of the most successful, widespread invasive reptile species and has become ubiquitous across tropical urban settings in the Western Hemisphere. Its ability to thrive in close proximity to humans has been linked to the rapid disappearance of native geckos. However, aspects of Hemidactylus mabouia natural history and ecomorphology, often assumed to be linked with this effect on native populations, remain understudied or untested. Here, we combine data from ∂15N and ∂13C stable isotopes, stomach contents, and morphometric analyses of traits associated with feeding and locomotion to test alternate hypotheses of displacement between H. mabouia and a native gecko, Phyllodactylus martini, on the island of Curaçao. We demonstrate substantial overlap of invertebrate prey resources between the species, with H. mabouia stomachs containing larger arthropod prey as well as vertebrate prey. We additionally show that H. mabouia possesses several morphological advantages, including larger sizes in feeding-associated traits and limb proportions that could offer a propulsive locomotor advantage on vertical surfaces. Together, these findings provide the first support for the hypotheses that invasive H. mabouia and native P. martini overlap in prey resources and that H. mabouia possess ecomorphological advantages over P. martini. This work provides critical context for follow-up studies of H. mabouia and P. martini natural history and direct behavioral experiments that may ultimately illuminate the mechanisms underlying displacement on this island and act as a potential model for other systems with Hemidactylus mabouia invasions.
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Affiliation(s)
- April D. Lamb
- Department of Bioinformatics and GenomicsUniversity of North CarolinaCharlotteNorth CarolinaUSA
- North Carolina Museum of Natural SciencesRaleighNorth CarolinaUSA
- Department of Applied EcologyNorth Carolina State UniversityRaleighNorth CarolinaUSA
| | - Catherine A. Lippi
- Department of GeographyQuantitative Disease Ecology and Conservation (QDEC) Lab GroupUniversity of FloridaGainesvilleFloridaUSA
| | | | - Andrew Jones
- Department of Ecology and Evolutionary BiologyYale UniversityNew HavenConnecticutUSA
| | - Dan L. Warren
- Biodiversity and Biocomplexity UnitOkinawa Institute of Science and Technology Graduate UniversityOnna, Kunigami DistrictOkinawa PrefectureJapan
| | - Teresa L. Iglesias
- Animal Resource SectionOkinawa Institute of Science and Technology Graduate UniversityOnna, Kunigami DistrictOkinawa PrefectureJapan
| | - Matthew C. Brandley
- Section of Amphibians and ReptilesCarnegie Museum of Natural HistoryPittsburghPennsylvaniaUSA
| | - Alex Dornburg
- Department of Bioinformatics and GenomicsUniversity of North CarolinaCharlotteNorth CarolinaUSA
- North Carolina Museum of Natural SciencesRaleighNorth CarolinaUSA
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Thiemann GW, Rode KD, Erlenbach JA, Budge SM, Robbins CT. 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. [PMID: 34687352 DOI: 10.1007/s00360-021-01414-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [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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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] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [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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15
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Ro H, Stern JH, Wirsing AJ, Quinn TP. Stable Isotopes Reveal Variation in Consumption of Pacific Salmon by Brown Bears, Despite Ready Access in Small Streams. Journal of Fish and Wildlife Management 2020; 12:40-9. [DOI: 10.3996/jfwm-20-034] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Abstract
Brown bears Ursus arctos consume a wide range of organisms, including ungulates and plants, but Pacific salmon Oncorhynchus spp. are especially important to their diet where their ranges overlap. Although some brown bears minimize antagonistic encounters with other brown bears or infanticide by avoiding streams where salmon spawn, studies generally assume that brown bears with ready access to salmon feed heavily on them. To test this assumption, and the hypothesis that male brown bears would feed more heavily on salmon than females (owing to their sexual size dimorphism), we collected hair samples from brown bears by using barbed wire placed on six small tributaries of Lake Aleknagik, Alaska, USA, where adult Sockeye Salmon Oncorhynchus nerka are readily accessible and frequently consumed by brown bears. Analysis of DNA distinguished among the different brown bears leaving the hair samples, some of which were sampled multiple times within and among years. We assessed the contribution of salmon to the diet of individual brown bears by using carbon and nitrogen stable isotope signatures. The 77 samples analyzed from 31 different bears over 4 y showed isotopic ratios consistent with reliance on salmon, but the wide range of isotopic signatures included values suggesting variable, and in one case considerable, use of terrestrial resources. Stable isotope signatures did not differ between male and female brown bears, nor did they differ between two sides of the lake, despite marked differences in Sockeye Salmon density. We collected the hair samples when salmon were present, so there was some uncertainty regarding whether they reflected feeding during the current or previous season. Notwithstanding this caveat, the results are consistent with the hypothesis that salmon were sufficiently available to provide food for the brown bears and that the considerable isotopic variation among brown bears with access to salmon reflected their age, status, and behavior.
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16
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Shave JR, Cherry SG, Derocher AE, Fortin D. Seasonal and inter-annual variation in diet for gray wolves Canis lupus in Prince Albert National Park, Saskatchewan. Wildlife Biology 2020. [DOI: 10.2981/wlb.00695] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
Affiliation(s)
- Justin R. Shave
- J. R. Shave ✉ and A. E. Derocher, Dept of Biological Sciences, Univ. of Alberta, Edmonton, AB, T6G 2E9, Canada
| | - Seth G. Cherry
- S. G. Cherry, Parks Canada Agency, Radium Hot Springs, BC, Canada
| | - Andrew E. Derocher
- J. R. Shave ✉ and A. E. Derocher, Dept of Biological Sciences, Univ. of Alberta, Edmonton, AB, T6G 2E9, Canada
| | - Daniel Fortin
- D. Fortin, Dépt de biologie and Centre d'étude de la Foret; Univ. Laval, Québec, QC, Canada
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17
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Funck J, Kellam C, Seaton CT, Wooller MJ. Stable isotopic signatures in modern wood bison (Bison bison athabascae) hairs as telltale biomarkers of nutritional stress. CAN J ZOOL 2020. [DOI: 10.1139/cjz-2019-0185] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Assessing the challenges faced by wildlife populations is key to providing effective management but is problematic when dealing with populations in remote locations. Analyses of the stable carbon and nitrogen isotope composition (expressed as δ13C and δ15N values) of sequentially grown tissues, such as hairs, can be used to track changes in the eco-physiology of organisms. We generated δ13C and δ15N values from sequentially sampled (n = 465) hairs taken from wood bison (Bison bison athabascae Rhoads, 1898) (n = 27). Samples were taken from individuals prior to and after their release from captivity into the lower Innoko–Yukon river area of Alaska in 2015. Twenty months after release, individuals had a distinct seasonal pattern in δ13C values. Hairs from individuals that experienced food scarcity or long-distance movement were sampled as case studies. Nutritional stress in these cases lead to a rise in δ15N values and a decrease in δ13C values. Applications of δ13C and δ15N analyses of bison tail hairs could provide wildlife managers a valuable and minimally invasive tool to better understand bison seasonal metabolic status and determine the historical health and behavior of living and dead individuals.
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Affiliation(s)
- Juliette Funck
- Department of Geology and Geoscience, University of Alaska Fairbanks, Fairbanks, AK 99775, USA
- Alaska Stable Isotope Facility, Water and Environmental Research Center, Institute of Northern Engineering, University of Alaska Fairbanks, Fairbanks, AK 99775, USA
| | - Cade Kellam
- Department of Biology and Wildlife, University of Alaska Fairbanks, Fairbanks, AK 99775, USA
| | - C. Tom Seaton
- Wood Bison Restoration Project, Alaska Department of Fish and Game, Fairbanks, AK 99701, USA
| | - Matthew J. Wooller
- Alaska Stable Isotope Facility, Water and Environmental Research Center, Institute of Northern Engineering, University of Alaska Fairbanks, Fairbanks, AK 99775, USA
- College of Fisheries and Ocean Sciences, University of Alaska Fairbanks, Fairbanks, AK 99775, USA
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18
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Rogers MC, Hilderbrand GV, Gustine DD, Joly K, Leacock WB, Mangipane BA, Welker JM. Splitting hairs: dietary niche breadth modelling using stable isotope analysis of a sequentially grown tissue. Isotopes Environ Health Stud 2020; 56:358-369. [PMID: 32631088 DOI: 10.1080/10256016.2020.1787404] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Accepted: 05/23/2020] [Indexed: 06/11/2023]
Abstract
Stable isotope data from durable, sequentially grown tissues (e.g. hair, claw, and baleen) is commonly used for modelling dietary niche breadth. The use of tissues grown over multiple months to years, however, has the potential to complicate isotopic niche breadth modelling, as time-averaged stable isotope signals from whole tissues may obscure information available from chronologically resolved stable isotope signals in serially sectioned tissues. We determined if whole samples of brown bear guard hair produced different isotopic niche breadth estimates than those produced from subsampled, serially sectioned samples of the same tissue from the same set of individuals. We sampled guard hair from brown bears (Ursus arctos) in four regions of Alaska with disparate biogeographies and dietary resource availability. Whole hair and serially sectioned hair samples were used to produce paired isotopic dietary niche breadth estimates for each region in the SIBER Bayesian model framework in R. Isotopic data from serially sectioned hair consistently produced larger estimates of isotopic dietary niche breadth than isotope data from whole hair samples. Serial sampling captures finer-scale changes in diet and when cumulatively used to estimate isotopic niche breadth, the serially sampled isotope data more fully captures dietary variability and true isotopic niche breadth.
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Affiliation(s)
- Matthew C Rogers
- Department of Biology and Wildlife, University of Alaska Fairbanks, Fairbanks, AK, USA
- NOAA Alaska Fisheries Science Center, Auke Bay Laboratories, Juneau, AK, USA
| | | | - David D Gustine
- National Park Service, Grand Teton National Park, Moose, WY, USA
| | - Kyle Joly
- National Park Service, Gates of the Arctic National Park and Preserve, Fairbanks, AK, USA
| | - William B Leacock
- US Fish and Wildlife Service, Kodiak National Wildlife Refuge, Kodiak, AK, USA
| | - Buck A Mangipane
- National Park Service, Lake Clark National Park and Preserve, Port Alsworth, AK, USA
| | - Jeffrey M Welker
- Department of Biological Sciences, University of Alaska Anchorage, Anchorage, AK, USA
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19
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Lippold A, Aars J, Andersen M, Aubail A, Derocher AE, Dietz R, Eulaers I, Sonne C, Welker JM, Wiig Ø, Routti H. Two Decades of Mercury Concentrations in Barents Sea Polar Bears ( Ursus maritimus) in Relation to Dietary Carbon, Sulfur, and Nitrogen. Environ Sci Technol 2020; 54:7388-7397. [PMID: 32410455 DOI: 10.1021/acs.est.0c01848] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Temporal trends of total mercury (THg) were examined in female polar bear (Ursus maritimus) hair (n = 199) from the Barents Sea in 1995-2016. In addition, hair values of stable isotopes (n = 190-197) of carbon (δ13C), sulfur (δ34S), and nitrogen (δ15N) and information on breeding status, body condition, and age were obtained. Stable isotope values of carbon and sulfur reflect dietary source (e.g., marine vs terrestrial) and the nitrogen trophic level. Values for δ13C and δ34S declined by -1.62 and -1.18‰ over the time of the study period, respectively, while values for δ15N showed no trend. Total Hg concentrations were positively related to both δ13C and δ34S. Yearly median THg concentrations ranged from 1.61 to 2.75 μg/g and increased nonlinearly by 0.86 μg/g in total over the study. Correcting THg concentrations for stable isotope values of carbon and sulfur and additionally breeding status and age slightly accelerated the increase in THg concentrations; however, confidence intervals of the raw THg trend and the corrected THg trend had substantial overlap. The rise in THg concentrations in the polar bear food web was possibly related to climate-related re-emissions of previously stored Hg from thawing sea-ice, glaciers, and permafrost.
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Affiliation(s)
- Anna Lippold
- Fram Centre, Norwegian Polar Institute, Tromsø 9296, Norway
| | - Jon Aars
- Fram Centre, Norwegian Polar Institute, Tromsø 9296, Norway
| | | | - Aurore Aubail
- Littoral, Environment and Societies (CNRS/La Rochelle University), La Rochelle 17000, France
| | - Andrew E Derocher
- Department of Biological Sciences, University of Alberta, Edmonton T6G 2E9, Canada
| | - Rune Dietz
- Institute of Bioscience, Arctic Research Centre, Aarhus University, Roskilde 4000, Denmark
| | - Igor Eulaers
- Institute of Bioscience, Arctic Research Centre, Aarhus University, Roskilde 4000, Denmark
| | - Christian Sonne
- Institute of Bioscience, Arctic Research Centre, Aarhus University, Roskilde 4000, Denmark
| | - Jeffrey M Welker
- University of Alaska Anchorage, Anchorage 99508, United States
- University of Oulu, Oulu 90014, Finland
- University of the Arctic, Rovaniemi 96460, Finland
| | - Øystein Wiig
- Fram Centre, Norwegian Polar Institute, Tromsø 9296, Norway
- Natural History Museum, University of Oslo, 0318 Oslo, Norway
| | - Heli Routti
- Fram Centre, Norwegian Polar Institute, Tromsø 9296, Norway
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20
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Blévin P, Aars J, Andersen M, Blanchet MA, Hanssen L, Herzke D, Jeffreys RM, Nordøy ES, Pinzone M, de la Vega C, Routti H. Pelagic vs Coastal-Key Drivers of Pollutant Levels in Barents Sea Polar Bears with Contrasted Space-Use Strategies. Environ Sci Technol 2020; 54:985-995. [PMID: 31823610 DOI: 10.1021/acs.est.9b04626] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
In the Barents Sea, pelagic and coastal polar bears are facing various ecological challenges that may explain the difference in their pollutant levels. We measured polychlorinated biphenyls, organochlorine pesticides, polybrominated diphenyl ethers in fat, and perfluoroalkyl substances in plasma in pelagic and coastal adult female polar bears with similar body condition. We studied polar bear feeding habits with bulk stable isotope ratios of carbon and nitrogen. Nitrogen isotopes of amino acids were used to investigate their trophic position. We studied energy expenditure by estimating field metabolic rate using telemetry data. Annual home range size was determined, and spatial gradients in pollutants were explored using latitude and longitude centroid positions of polar bears. Pollutant levels were measured in harp seals from the Greenland Sea and White Sea-Barents Sea as a proxy for a West-East gradient of pollutants in polar bear prey. We showed that pelagic bears had higher pollutant loads than coastal bears because (1) they feed on a higher proportion of marine and higher trophic level prey, (2) they have higher energy requirements and higher prey consumption, (3) they forage in the marginal ice zones, and (4) they feed on prey located closer to pollutant emission sources/transport pathways.
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Affiliation(s)
- Pierre Blévin
- Norwegian Polar Institute, Fram Centre , Tromsø 9296 , Norway
| | - Jon Aars
- Norwegian Polar Institute, Fram Centre , Tromsø 9296 , Norway
| | - Magnus Andersen
- Norwegian Polar Institute, Fram Centre , Tromsø 9296 , Norway
| | | | - Linda Hanssen
- Norwegian Institute for Air Research, Fram Centre , Tromsø 9296 , Norway
| | - Dorte Herzke
- Norwegian Institute for Air Research, Fram Centre , Tromsø 9296 , Norway
| | - Rachel M Jeffreys
- School of Environmental Science , University of Liverpool , Liverpool L69 7ZX , United Kingdom
| | | | - Marianna Pinzone
- Laboratory of Oceanology, Department of Biology, Ecology & Evolution , University of Liège , Liège B-4000 , Belgium
| | - Camille de la Vega
- School of Environmental Science , University of Liverpool , Liverpool L69 7ZX , United Kingdom
| | - Heli Routti
- Norwegian Polar Institute, Fram Centre , Tromsø 9296 , Norway
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21
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Stanek A, Wolf N, Welker J, Jensen S. Experimentally derived incorporation rates and diet-to-tissue discrimination values for carbon and nitrogen stable isotopes in gray wolves (Canis lupus) fed a marine diet. CAN J ZOOL 2019. [DOI: 10.1139/cjz-2019-0049] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Recent studies have noted the differential effects of marine versus terrestrial diets on the carbon and nitrogen stable isotope (13C and 15N, respectively) diet-to-tissue discrimination values and incorporation rates for omnivorous and carnivorous mammals. Inaccurate estimates of these parameters may result in misrepresentation of diet composition or in the timing of diet shifts. Here, we present the results of a diet-switch experiment designed to estimate diet-to-tissue discrimination values and incorporation rates for tissues of gray wolves (Canis lupus Linnaeus, 1758) fed a diet of Pacific salmon (genus Oncorhynchus Suckley, 1861). Our results demonstrate substantial differences in both parameters between wolves maintained on a marine (salmon) diet and wolves maintained on terrestrially sourced prey (beef, Bos taurus Linnaeus, 1758). Increased awareness of the significance of marine resources to omnivorous and carnivorous consumers, like wolves, highlights the importance of phenomenological and mechanistic understandings of the effects of fish and other marine prey on dietary investigations based on stable isotopes.
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Affiliation(s)
- A.E. Stanek
- Department of Biological Sciences, University of Alaska Anchorage, 3211 Providence Drive, Anchorage, AK 99508, USA
| | - N. Wolf
- Department of Biological Sciences, University of Alaska Anchorage, 3211 Providence Drive, Anchorage, AK 99508, USA
| | - J.M. Welker
- Department of Biological Sciences, University of Alaska Anchorage, 3211 Providence Drive, Anchorage, AK 99508, USA
- Ecology and Genetics Research Unit, University of Oulu, Finland 90014, and UArctic Research Chair
| | - S. Jensen
- The Alaska Zoo, 4731 O’Malley Road, Anchorage, AK 99507, USA
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22
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Javornik J, Hopkins JB, Zavadlav S, Levanič T, Lojen S, Polak T, Jerina K. Effects of ethanol storage and lipids on stable isotope values in a large mammalian omnivore. J Mammal 2019. [DOI: 10.1093/jmammal/gyy187] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Jernej Javornik
- Biotechnical Faculty, Department of Forestry, University of Ljubljana, Večna pot, Ljubljana, Slovenia
| | - John B Hopkins
- Biotechnical Faculty, Department of Forestry, University of Ljubljana, Večna pot, Ljubljana, Slovenia
- School of Biodiversity Conservation, Unity College, Unity, ME, USA
| | - Saša Zavadlav
- Biotechnical Faculty, Department of Forestry, University of Ljubljana, Večna pot, Ljubljana, Slovenia
- Department of Yield and Silviculture, Slovenian Forestry Institute, Večna pot, Ljubljana, Slovenia
| | - Tom Levanič
- Biotechnical Faculty, Department of Forestry, University of Ljubljana, Večna pot, Ljubljana, Slovenia
- Department of Yield and Silviculture, Slovenian Forestry Institute, Večna pot, Ljubljana, Slovenia
| | - Sonja Lojen
- Biotechnical Faculty, Department of Forestry, University of Ljubljana, Večna pot, Ljubljana, Slovenia
- Department of Environmental Sciences, Jožef Stefan Institute, Jamova cesta, Ljubljana, Slovenia
- School of Environmental Sciences, University of Nova Gorica, Lanthieri mansion, Glavni,Vipava, Slovenia
| | - Tomaž Polak
- Biotechnical Faculty, Department of Food Science and Technology, University of Ljubljana, Jamnikarjeva, Ljubljana, Slovenia
| | - Klemen Jerina
- Biotechnical Faculty, Department of Forestry, University of Ljubljana, Večna pot, Ljubljana, Slovenia
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23
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McHuron EA, Holser RR, Costa DP. What's in a whisker? Disentangling ecological and physiological isotopic signals. Rapid Commun Mass Spectrom 2019; 33:57-66. [PMID: 30334287 DOI: 10.1002/rcm.8312] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Revised: 10/10/2018] [Accepted: 10/11/2018] [Indexed: 06/08/2023]
Abstract
RATIONALE Stable isotope analysis of keratinized tissues is an informative tool for quantifying foraging ecology that can address questions related to niche specialization and temporal variation in behavior. Application of this approach relies on an understanding of tissue growth and how isotope ratios relate to physiological and ecological processes, data that are lacking for many species. METHODS We collected paired whisker length measurements from northern elephant seals to estimate growth and shedding patterns (n = 16). A subset of seals (n = 5) carried a satellite tag and time-depth recorder across the 7+ month foraging trip following the annual pelage molt. Stable isotopes of carbon and nitrogen were measured in whisker segments grown across the 6+ week fasting on land and the subsequent foraging trip; profiles were combined with growth parameters to timestamp each segment and investigate relationships with foraging behavior. RESULTS Whisker loss and initial regrowth primarily occurred during the annual pelage molt, but newly grown whiskers exhibited active, nonlinear growth across the foraging trip. The δ13 C and δ15 N values were higher in segments grown on land than at sea and exhibited a characteristic decline upon departure from the rookery. There was a relationship between latitude and longitude and δ15 N values, and individual whisker segments grown at sea could be classified to the correct ecoregion with 81% accuracy. CONCLUSIONS Fasting affected both δ13 C and δ15 N values and the ability to exclude these values from ecological investigations is crucial given the temporal overlap with tissue growth. The rapid decline in isotope ratios upon departure can be used to isolate portions of the whisker with a strong physiological signal, even for whiskers with unknown growth histories. The active growth across the foraging trip combined with the ability to identify differences in foraging behavior validates the utility of this approach for addressing ecological questions.
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Affiliation(s)
- Elizabeth A McHuron
- Department of Ecology and Evolution, University of California Santa Cruz, Santa Cruz, CA, 95060, USA
| | - Rachel R Holser
- Department of Ecology and Evolution, University of California Santa Cruz, Santa Cruz, CA, 95060, USA
| | - Daniel P Costa
- Department of Ecology and Evolution, University of California Santa Cruz, Santa Cruz, CA, 95060, USA
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24
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Lippold A, Bourgeon S, Aars J, Andersen M, Polder A, Lyche JL, Bytingsvik J, Jenssen BM, Derocher AE, Welker JM, Routti H. Temporal Trends of Persistent Organic Pollutants in Barents Sea Polar Bears ( Ursus maritimus) in Relation to Changes in Feeding Habits and Body Condition. Environ Sci Technol 2019; 53:984-995. [PMID: 30548071 DOI: 10.1021/acs.est.8b05416] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Temporal trends of persistent organic pollutants (POPs: PCBs, OH-PCBs, p, p'-DDE, HCB, β-HCH, oxychlordane, BDE-47, and 153) in relation to changes in feeding habits and body condition in adult female polar bears ( Ursus maritimus) from the Barents Sea subpopulation were examined over 20 years (1997-2017). All 306 samples were collected in the spring (April). Both stable isotope values of nitrogen (δ15N) and carbon (δ13C) from red blood cells declined over time, with a steeper trend for δ13C between 2012 and 2017, indicating a decreasing intake of marine and high trophic level prey items. Body condition, based on morphometric measurements, had a nonsignificant decreasing tendency between 1997 and 2005, and increased significantly between 2005 and 2017. Plasma concentrations of BDE-153 and β-HCH did not significantly change over time, whereas concentrations of Σ4PCB, Σ5OH-PCB, BDE-47, and oxychlordane declined linearly. Concentrations of p, p'-DDE and HCB, however, declined until 2012 and 2009, respectively, and increased thereafter. Changes in feeding habits and body condition did not significantly affect POP trends. The study indicates that changes in diet and body condition were not the primary driver of POPs in polar bears, but were controlled in large part by primary and/or secondary emissions of POPs.
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Affiliation(s)
- Anna Lippold
- Norwegian Polar Institute , Tromsø 9296 , Norway
- The Arctic University of Norway (UiT) , Tromsø 9019 , Norway
| | - Sophie Bourgeon
- The Arctic University of Norway (UiT) , Tromsø 9019 , Norway
| | - Jon Aars
- Norwegian Polar Institute , Tromsø 9296 , Norway
| | | | - Anuschka Polder
- Norwegian University of Life Sciences (NMBU) , Oslo 0454 , Norway
| | - Jan Ludvig Lyche
- Norwegian University of Life Sciences (NMBU) , Oslo 0454 , Norway
| | - Jenny Bytingsvik
- Akvaplan-niva AS , Tromsø 9296 , Norway
- Norwegian University of Science and Technology (NTNU) Trondheim 7491 , Norway
| | - Bjørn Munro Jenssen
- Norwegian University of Science and Technology (NTNU) Trondheim 7491 , Norway
| | | | - Jeffrey M Welker
- University of Alaska Anchorage (UAA) , Anchorage 99508 , United States
- University of Oulu , Oulu 90014 , Finland
- University of the Arctic
| | - Heli Routti
- Norwegian Polar Institute , Tromsø 9296 , Norway
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Scotter SE, Tryland M, Nymo IH, Hanssen L, Harju M, Lydersen C, Kovacs KM, Klein J, Fisk AT, Routti H. Contaminants in Atlantic walruses in Svalbard part 1: Relationships between exposure, diet and pathogen prevalence. Environ Pollut 2019; 244:9-18. [PMID: 30317087 DOI: 10.1016/j.envpol.2018.10.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Revised: 09/26/2018] [Accepted: 10/01/2018] [Indexed: 06/08/2023]
Abstract
This study investigated relationships between organohalogen compound (OHC) exposure, feeding habits, and pathogen exposure in a recovering population of Atlantic walruses (Odobenus rosmarus rosmarus) from the Svalbard Archipelago, Norway. Various samples were collected from 39 free-living, apparently healthy, adult male walruses immobilised at three sampling locations during the summers of 2014 and 2015. Concentrations of lipophilic compounds (polychlorinated biphenyls, organochlorine pesticides and polybrominated diphenyl ethers) were analysed in blubber samples, and concentrations of perfluoroalkylated substances (PFASs) were determined in plasma samples. Stable isotopes of carbon and nitrogen were measured in seven tissue types and surveys for three infectious pathogens were conducted. Despite an overall decline in lipophilic compound concentrations since this population was last studied (2006), the contaminant pattern was similar, including extremely large inter-individual variation. Stable isotope ratios of carbon and nitrogen showed that the variation in OHC concentrations could not be explained by some walruses consuming higher trophic level diets, since all animals were found to feed at a similar trophic level. Antibodies against the bacteria Brucella spp. and the parasite Toxoplasma gondii were detected in 26% and 15% of the walruses, respectively. Given the absence of seal-predation, T. gondii exposure likely took place via the consumption of contaminated bivalves. The source of exposure to Brucella spp. in walruses is still unknown. Parapoxvirus DNA was detected in a single individual, representing the first documented evidence of parapoxvirus in wild walruses. Antibody prevalence was not related to contaminant exposure. Despite this, dynamic relationships between diet composition, contaminant bioaccumulation and pathogen exposure warrant continuing attention given the likelihood of climate change induced habitat and food web changes, and consequently OHC exposure, for Svalbard walruses in the coming decades.
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Affiliation(s)
- Sophie E Scotter
- Department of Arctic and Marine Biology, UiT The Arctic University of Norway, N-9019, Tromsø, Norway
| | - Morten Tryland
- Department of Arctic and Marine Biology, UiT The Arctic University of Norway, N-9019, Tromsø, Norway
| | - Ingebjørg H Nymo
- Department of Arctic and Marine Biology, UiT The Arctic University of Norway, N-9019, Tromsø, Norway; Norwegian Veterinary Institute, Stakkevollveien 23, N-9010, Tromsø, Norway
| | - Linda Hanssen
- Norwegian Institute for Air Research (NILU), Fram Centre, N-9296, Tromsø, Norway
| | - Mikael Harju
- Norwegian Institute for Air Research (NILU), Fram Centre, N-9296, Tromsø, Norway
| | | | - Kit M Kovacs
- Norwegian Polar Institute, FRAM Centre, N-9296, Tromsø, Norway
| | - Jörn Klein
- University College of Southeast Norway (USN), Post Box 235, N-3603, Kongsberg, Norway
| | - Aaron T Fisk
- Great Lakes Institute for Environmental Research, University of Windsor, Windsor, Ontario, N9B 3P4, Canada
| | - Heli Routti
- Norwegian Polar Institute, FRAM Centre, N-9296, Tromsø, Norway.
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L'Hérault V, Lecomte N, Truchon MH, Berteaux D. Discrimination factors of carbon and nitrogen stable isotopes from diet to hair in captive large Arctic carnivores of conservation concern. Rapid Commun Mass Spectrom 2018; 32:1773-1780. [PMID: 30030922 DOI: 10.1002/rcm.8239] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Revised: 05/30/2018] [Accepted: 07/12/2018] [Indexed: 06/08/2023]
Abstract
RATIONALE Stable isotope analysis is widely used to reconstruct diet, delineate trophic interactions, and determine energy pathways. Such ecological inferences are based on the idea that animals are, isotopically, what they eat but with a predictable difference between the isotopic ratio of a consumer and that of its diet, coined as the discrimination factor. Providing correct estimates of diet-consumer isotopic discrimination in controlled conditions is key for a robust application of the stable isotopes technique in the wild. METHODS Using a Finnigan Mat Delta Plus isotope-ratio mass spectrometer, we investigated isotopic discrimination of carbon and nitrogen isotope ratios (δ13 C and δ15 N values) in guard hairs of four Arctic predators; the wolf (n = 7), the wolverine (n = 2), the grizzly bear (n = 2), and the polar bear (n = 3). During a 3-month trial, carnivores were fed a mixed diet. The δ13 C and δ15 N values, and the mass (g) of diet items, were monitored weekly for each individual to determine their Total Diet Average ratios. RESULTS Diet-hair isotopic discrimination (Δx) varied according to species, ranging [1.88 ± 0.69‰: 3.2 ± 0.69‰] for δ13 C values, and [1.58 ± 0.17‰: 3.81 ± 0.22‰] for δ15 N values. Adult wolves Δ13 C average (2.03 ± 0.7‰) was lower than that of young wolves (2.60 ± 0.8‰) and any other species (combined average of 2.59 ± 0.28‰), except for the wolverine (2.12 ± 0.23‰). Wolves Δ15 N averages (juveniles: 3.51 ± 0.34‰, adults: 3.68 ± 0.28‰) were higher than those of any other species (combined average: 2.50 ± 0.58‰). CONCLUSIONS The discrimination factors for δ13 C and δ15 N values calculated in this study could be used in ecological studies dealing with free-ranging animals, with implications for non-invasive research approaches. As in other controlled discrimination studies, we recommend caution in applying our discrimination factors when the population structure is heterogeneous.
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Affiliation(s)
- Vincent L'Hérault
- Canada Research Chair on Northern Biodiversity and Centre for Northern Studies, Université du Québec à Rimouski, QC, Canada, G5L 3A1
- ARCTIConnexion, Québec City, QC, Canada, G1L 1Y8
| | - Nicolas Lecomte
- Canada Research Chair in Polar and Boreal Ecology, Université de Moncton, Moncton, NB, Canada, E1A 3E9
| | | | - Dominique Berteaux
- Canada Research Chair on Northern Biodiversity and Centre for Northern Studies, Université du Québec à Rimouski, QC, Canada, G5L 3A1
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Tartu S, Aars J, Andersen M, Polder A, Bourgeon S, Merkel B, Lowther AD, Bytingsvik J, Welker JM, Derocher AE, Jenssen BM, Routti H. Choose Your Poison-Space-Use Strategy Influences Pollutant Exposure in Barents Sea Polar Bears. Environ Sci Technol 2018; 52:3211-3221. [PMID: 29363970 DOI: 10.1021/acs.est.7b06137] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Variation in space-use is common within mammal populations. In polar bears, Ursus maritimus, some individuals follow the sea ice (offshore bears) whereas others remain nearshore yearlong (coastal bears). We studied pollutant exposure in relation to space-use patterns (offshore vs coastal) in adult female polar bears from the Barents Sea equipped with satellite collars (2000-2014, n = 152). First, we examined the differences in home range (HR) size and position, body condition, and diet proxies (nitrogen and carbon stable isotopes, n = 116) between offshore and coastal space-use. Second, we investigated how HR, space-use, body condition, and diet were related to plasma concentrations of polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs) ( n = 113), perfluoroalkyl substances (PFASs; n = 92), and hydroxylated-PCBs ( n = 109). Offshore females were in better condition and had a more specialized diet than did coastal females. PCBs, OCPs, and hydroxylated-PCB concentrations were not related to space-use strategy, yet PCB concentrations increased with increasing latitude, and hydroxylated-PCB concentrations were positively related to HR size. PFAS concentrations were 30-35% higher in offshore bears compared to coastal bears and also increased eastward. On the basis of the results we conclude that space-use of Barents Sea female polar bears influences their pollutant exposure, in particular plasma concentrations of PFAS.
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Affiliation(s)
- Sabrina Tartu
- Norwegian Polar Institute , Fram Centre , Tromsø NO-9296 , Norway
| | - Jon Aars
- Norwegian Polar Institute , Fram Centre , Tromsø NO-9296 , Norway
| | - Magnus Andersen
- Norwegian Polar Institute , Fram Centre , Tromsø NO-9296 , Norway
| | - Anuschka Polder
- Norwegian University of Life Science , Campus Adamstua , Oslo NO-1432 , Norway
| | - Sophie Bourgeon
- UiT-The Arctic University of Norway , Department of Arctic and Marine Biology , Tromsø NO-9010 , Norway
| | - Benjamin Merkel
- Norwegian Polar Institute , Fram Centre , Tromsø NO-9296 , Norway
| | - Andrew D Lowther
- Norwegian Polar Institute , Fram Centre , Tromsø NO-9296 , Norway
| | | | - Jeffrey M Welker
- Department of Biological Sciences , University of Alaska-Anchorage , Anchorage , Alaska 99508 , United States
- Department of Arctic Technology , University Center in Svalbard , Longyearbyen, Svalbard NO-9171 , Norway
| | - Andrew E Derocher
- Department of Biological Sciences , University of Alberta , Edmonton T6G 2R3 , Canada
| | - Bjørn Munro Jenssen
- Department of Arctic Technology , University Center in Svalbard , Longyearbyen, Svalbard NO-9171 , Norway
- Department of Biology , Norwegian University of Science and Technology , Trondheim NO-7491 , Norway
| | - Heli Routti
- Norwegian Polar Institute , Fram Centre , Tromsø NO-9296 , Norway
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Whiteman JP, Harlow HJ, Durner GM, Regehr EV, Amstrup SC, Ben-David M. Phenotypic plasticity and climate change: can polar bears respond to longer Arctic summers with an adaptive fast? Oecologia 2017; 186:369-381. [DOI: 10.1007/s00442-017-4023-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Accepted: 11/22/2017] [Indexed: 02/02/2023]
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Routti H, Aars J, Fuglei E, Hanssen L, Lone K, Polder A, Pedersen ÅØ, Tartu S, Welker JM, Yoccoz NG. Emission Changes Dwarf the Influence of Feeding Habits on Temporal Trends of Per- and Polyfluoroalkyl Substances in Two Arctic Top Predators. Environ Sci Technol 2017; 51:11996-12006. [PMID: 28918622 DOI: 10.1021/acs.est.7b03585] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
We monitored concentrations of per- and polyfluoroalkyl substances (PFASs) in relation to climate-associated changes in feeding habits and food availability in polar bears (Ursus maritimus) and arctic foxes (Vulpes lagopus) (192 plasma and 113 liver samples, respectively) sampled from Svalbard, Norway, during 1997-2014. PFASs concentrations became greater with increasing dietary trophic level, as bears and foxes consumed more marine as opposed to terrestrial food, and as the availability of sea ice habitat increased. Long-chained perfluoroalkyl carboxylates (PFCAs) in arctic foxes decreased with availability of reindeer carcasses. The ∼9-14% yearly decline of C6-8 perfluoroalkyl sulfonates (PFSAs) following the cease in C6-8 PFSA precursor production in 2001 indicates that the peak exposure was mainly a result of atmospheric transport of the volatile precursors. However, the stable PFSA concentrations since 2009-2010 suggest that Svalbard biota is still exposed to ocean-transported PFSAs. Long-chain ocean-transported PFCAs increased 2-4% per year and the increase in C12-14 PFCAs in polar bears tended to level off since ∼2009. Emerging short-chain PFASs showed no temporal changes. Climate-related changes in feeding habits and food availability moderately affected PFAS trends. Our results indicate that PFAS concentrations in polar bears and arctic foxes are mainly affected by emissions.
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Affiliation(s)
- Heli Routti
- Norwegian Polar Institute , Fram Centre, Tromsø, Norway
| | - Jon Aars
- Norwegian Polar Institute , Fram Centre, Tromsø, Norway
| | - Eva Fuglei
- Norwegian Polar Institute , Fram Centre, Tromsø, Norway
| | - Linda Hanssen
- Norwegian Institute for Air Research , Fram Centre, Tromsø, Norway
| | - Karen Lone
- Norwegian Polar Institute , Fram Centre, Tromsø, Norway
| | - Anuschka Polder
- Norwegian University of Life Sciences , Campus Adamstua, Oslo, Norway
| | | | - Sabrina Tartu
- Norwegian Polar Institute , Fram Centre, Tromsø, Norway
| | - Jeffrey M Welker
- University of Alaska Anchorage , Department of Biological Sciences, Anchorage, Alaska 99508, United States
| | - Nigel G Yoccoz
- UiT-The Arctic University of Norway , Department of Arctic and Marine Biology, Tromsø, Norway
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Tartu S, Bourgeon S, Aars J, Andersen M, Lone K, Jenssen BM, Polder A, Thiemann GW, Torget V, Welker JM, Routti H. Diet and metabolic state are the main factors determining concentrations of perfluoroalkyl substances in female polar bears from Svalbard. Environ Pollut 2017; 229:146-158. [PMID: 28587979 DOI: 10.1016/j.envpol.2017.04.100] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Revised: 04/05/2017] [Accepted: 04/29/2017] [Indexed: 05/26/2023]
Abstract
Perfluoroalkyl substances (PFASs) have been detected in organisms worldwide, including Polar Regions. The polar bear (Ursus maritimus), the top predator of Arctic marine ecosystems, accumulates high concentrations of PFASs, which may be harmful to their health. The aim of this study was to investigate which factors (habitat quality, season, year, diet, metabolic state [i.e. feeding/fasting], breeding status and age) predict PFAS concentrations in female polar bears captured on Svalbard (Norway). We analysed two perfluoroalkyl sulfonates (PFSAs: PFHxS and PFOS) and C8-C13 perfluoroalkyl carboxylates (PFCAs) in 112 plasma samples obtained in April and September 2012-2013. Nitrogen and carbon stable isotope ratios (δ15N, δ13C) in red blood cells and plasma, and fatty acid profiles in adipose tissue were used as proxies for diet. We determined habitat quality based on movement patterns, capture position and resource selection functions, which are models that predict the probability of use of a resource unit. Plasma urea to creatinine ratios were used as proxies for metabolic state (i.e. feeding or fasting state). Results were obtained from a conditional model averaging of 42 general linear mixed models. Diet was the most important predictor of PFAS concentrations. PFAS concentrations were positively related to trophic level and marine diet input. High PFAS concentrations in females feeding on the eastern part of Svalbard, where the habitat quality was higher than on the western coast, were likely related to diet and possibly to abiotic factors. Concentrations of PFSAs and C8-C10 PFCAs were higher in fasting than in feeding polar bears and PFOS was higher in females with cubs of the year than in solitary females. Our findings suggest that female polar bears that are exposed to the highest levels of PFAS are those 1) feeding on high trophic level sea ice-associated prey, 2) fasting and 3) with small cubs.
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Affiliation(s)
- Sabrina Tartu
- Norwegian Polar Institute, Fram Centre, Tromsø, Norway.
| | - Sophie Bourgeon
- Norwegian Polar Institute, Fram Centre, Tromsø, Norway; UiT-The Arctic University of Norway, Department of Arctic and Marine Biology, Tromsø, Norway
| | - Jon Aars
- Norwegian Polar Institute, Fram Centre, Tromsø, Norway
| | | | - Karen Lone
- Norwegian Polar Institute, Fram Centre, Tromsø, Norway
| | - Bjørn Munro Jenssen
- Norwegian University of Science and Technology, Department of Biology, Trondheim, Norway
| | - Anuschka Polder
- Norwegian University of Life Science, Campus Adamstua, Oslo, Norway
| | | | - Vidar Torget
- Norwegian University of Science and Technology, Department of Biology, Trondheim, Norway
| | - Jeffrey M Welker
- University of Alaska Anchorage, Department of Biological Sciences, Anchorage, AK, USA; University Center in Svalbard, Longyearbyen, Svalbard, Norway
| | - Heli Routti
- Norwegian Polar Institute, Fram Centre, Tromsø, Norway
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Kirby R, Macfarland DM, Pauli JN. Consumption of intentional food subsidies by a hunted carnivore: Carnivore Use of Subsidies. J Wildl Manage 2017; 81:1161-9. [DOI: 10.1002/jwmg.21304] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Ferguson SH, Young BG, Yurkowski DJ, Anderson R, Willing C, Nielsen O. Demographic, ecological, and physiological responses of ringed seals to an abrupt decline in sea ice availability. PeerJ 2017; 5:e2957. [PMID: 28168119 PMCID: PMC5292026 DOI: 10.7717/peerj.2957] [Citation(s) in RCA: 72] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Accepted: 01/04/2017] [Indexed: 01/19/2023] Open
Abstract
To assess whether demographic declines of Arctic species at the southern limit of their range will be gradual or punctuated, we compared large-scale environmental patterns including sea ice dynamics to ringed seal (Pusa hispida) reproduction, body condition, recruitment, and stress in Hudson Bay from 2003 to 2013. Aerial surveys suggested a gradual decline in seal density from 1995 to 2013, with the lowest density occurring in 2013. Body condition decreased and stress (cortisol) increased over time in relation to longer open water periods. The 2010 open water period in Hudson Bay coincided with extremes in large-scale atmospheric patterns (North Atlantic Oscillation, Arctic Oscillation, El Nino-Southern Oscillation) resulting in the earliest spring breakup and the latest ice formation on record. The warming event was coincident with high stress level, low ovulation rate, low pregnancy rate, few pups in the Inuit harvest, and observations of sick seals. Results provide evidence of changes in the condition of Arctic marine mammals in relation to climate mediated sea ice dynamics. We conclude that although negative demographic responses of Hudson Bay seals are occurring gradually with diminishing sea ice, a recent episodic environmental event played a significant role in a punctuated population decline.
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Affiliation(s)
- Steven H. Ferguson
- Fisheries and Oceans Canada, Winnipeg, MB, Canada
- Department of Biological Sciences, University of Manitoba, Winnipeg, MB, Canada
- Centre for Earth Observation Science, University of Manitoba, Winnipeg, MB, Canada
| | - Brent G. Young
- Fisheries and Oceans Canada, Winnipeg, MB, Canada
- Department of Biological Sciences, University of Manitoba, Winnipeg, MB, Canada
| | - David J. Yurkowski
- Fisheries and Oceans Canada, Winnipeg, MB, Canada
- Department of Biological Sciences, University of Manitoba, Winnipeg, MB, Canada
| | - Randi Anderson
- Department of Biological Sciences, University of Manitoba, Winnipeg, MB, Canada
| | - Cornelia Willing
- Department of Biological Sciences, University of Manitoba, Winnipeg, MB, Canada
- Centre for Earth Observation Science, University of Manitoba, Winnipeg, MB, Canada
| | - Ole Nielsen
- Fisheries and Oceans Canada, Winnipeg, MB, Canada
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Jouta J, Dietz MW, Reneerkens J, Piersma T, Rakhimberdiev E, Hallgrímsson GT, Pen I. Ecological forensics: using single point stable isotope values to infer seasonal schedules of animals after two diet switches. Methods Ecol Evol 2016. [DOI: 10.1111/2041-210x.12695] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- Jeltje Jouta
- Department of Coastal Systems and Utrecht University NIOZ Royal Netherlands Institute for Sea Research P.O. Box 59, 1790 AB Den Burg Texel The Netherlands
- Groningen Institute for Evolutionary Life Sciences (GELIFES) University of Groningen P.O. Box 11103 9700 CC Groningen The Netherlands
| | - Maurine W. Dietz
- Groningen Institute for Evolutionary Life Sciences (GELIFES) University of Groningen P.O. Box 11103 9700 CC Groningen The Netherlands
| | - Jeroen Reneerkens
- Groningen Institute for Evolutionary Life Sciences (GELIFES) University of Groningen P.O. Box 11103 9700 CC Groningen The Netherlands
| | - Theunis Piersma
- Department of Coastal Systems and Utrecht University NIOZ Royal Netherlands Institute for Sea Research P.O. Box 59, 1790 AB Den Burg Texel The Netherlands
- Groningen Institute for Evolutionary Life Sciences (GELIFES) University of Groningen P.O. Box 11103 9700 CC Groningen The Netherlands
| | - Eldar Rakhimberdiev
- Department of Coastal Systems and Utrecht University NIOZ Royal Netherlands Institute for Sea Research P.O. Box 59, 1790 AB Den Burg Texel The Netherlands
- Department of Vertebrate Zoology Lomonosov Moscow State University 119991 Moscow Russia
| | | | - Ido Pen
- Groningen Institute for Evolutionary Life Sciences (GELIFES) University of Groningen P.O. Box 11103 9700 CC Groningen The Netherlands
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