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Barnas AF, Simone CAB, Geldart EA, Love OP, Jagielski PM, Gilchrist HG, Richardson ES, Dey CJ, Semeniuk CAD. An interspecific foraging association with polar bears increases foraging opportunities for avian predators in a declining Arctic seabird colony. Ecol Evol 2024; 14:e11012. [PMID: 38469043 PMCID: PMC10926061 DOI: 10.1002/ece3.11012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Revised: 12/04/2023] [Accepted: 12/06/2023] [Indexed: 03/13/2024] Open
Abstract
Interspecific foraging associations (IFAs) are biological interactions where two or more species forage in association with each other. Climate-induced reductions in Arctic sea ice have increased polar bear (Ursus maritimus) foraging in seabird colonies, which creates foraging opportunities for avian predators. We used drone video of bears foraging within a common eider (Somateria mollissima) colony on East Bay Island (Nunavut, Canada) in 2017 to investigate herring gull (Larus argentatus) foraging in association with bears. We recorded nest visitation by gulls following n = 193 eider flushing events from nests during incubation. The probability of gulls visiting eider nests increased with higher number of gulls present (β = 0.14 ± 0.03 [SE], p < .001) and for nests previously visited by a bear (β = 1.14 ± 0.49 [SE], p < .02). In our model examining the probability of gulls consuming eggs from nests, we failed to detect statistically significant effects for the number of gulls present (β = 0.09 ± 0.05 [SE], p < .07) or for nests previously visited by a bear (β = -0.92 ± 0.71 [SE], p < .19). Gulls preferred to visit nests behind bears (χ2 = 18, df = 1, p < .0001), indicating gulls are risk averse in the presence of polar bears. Our study provides novel insights on an Arctic IFA, and we present evidence that gulls capitalize on nests made available due to disturbance associated with foraging bears, as eiders disturbed off their nest allow gulls easier access to eggs. We suggest the IFA between gulls and polar bears is parasitic, as gulls are consuming terrestrial resources which would have eventually been consumed by bears. This finding has implications for estimating the energetic contribution of bird eggs to polar bear summer diets in that the total number of available clutches to consume may be reduced due to avian predators.
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Affiliation(s)
- Andrew F. Barnas
- Department of Integrative BiologyUniversity of WindsorWindsorOntarioCanada
- School of Environmental StudiesUniversity of VictoriaVictoriaBritish ColumbiaCanada
| | | | - Erica A. Geldart
- Department of Integrative BiologyUniversity of WindsorWindsorOntarioCanada
| | - Oliver P. Love
- Department of Integrative BiologyUniversity of WindsorWindsorOntarioCanada
| | | | - H. Grant Gilchrist
- National Wildlife Research Centre, Science and Technology BranchEnvironment and Climate Change CanadaOttawaOntarioCanada
| | - Evan S. Richardson
- Science and Technology BranchEnvironment and Climate Change CanadaOttawaOntarioCanada
| | - Cody J. Dey
- Department of Integrative BiologyUniversity of WindsorWindsorOntarioCanada
- Science and Technology BranchEnvironment and Climate Change CanadaOttawaOntarioCanada
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Galicia MP, Thiemann GW, Dyck MG, Ferguson SH. Are tissue samples obtained via remote biopsy useful for fatty acid-based diet analyses in a free-ranging carnivore? J Mammal 2021. [DOI: 10.1093/jmammal/gyab041] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Abstract
Fundamental knowledge on free-ranging animals has been obtained through capture-based studies; however, these may be logistically intensive, financially expensive, and potentially inconsistent with local cultural values. Genetic mark–recapture using remote tissue sampling has emerged as a less invasive alternative to capture-based population surveys but provides fewer opportunities to collect samples and measurements for broader ecological studies. We compared lipid content, fatty acid (FA) composition, and diet estimates from adipose tissue of polar bears (Ursus maritimus) obtained from two collection methods: remote biopsies (n = 138) sampled from helicopters and hunter-collected tissue (n = 499) from bears harvested in Davis Strait and Gulf of Boothia, Nunavut, 2010 – 2018. Lipid content of adipose tissue was lower in remote biopsies than harvest samples likely because remote biopsies removed only the outermost layer of subcutaneous tissue, rather than the more metabolically dynamic innermost tissue obtained from harvest samples. In contrast, FA composition was similar between the two collection methods with relatively small proportional differences in individual FAs. For diet estimates in Davis Strait, collection method was not a predictor of prey contribution to diet. In Gulf of Boothia, collection method was a predictor for some prey types, but the differences were relatively minor; the rank order of prey types was similar (e.g., ringed seal; Pusa hispida was consistently the primary prey in diets) and prey proportions differed by < 6% between the collection methods. Results from both methods showed that diets varied by geographic area, season, year, age class, and sex. Our study demonstrates that adipose tissue from remote biopsy provides reliable estimates of polar bear diet based on FA analysis and can be used to monitor underlying ecological changes in Arctic marine food webs.
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Affiliation(s)
| | - Gregory W Thiemann
- Faculty of Environmental and Urban Change, York University, Toronto, Ontario, Canada
| | - Markus G Dyck
- Wildlife Research Section, Department of Environment, Government of Nunavut, Igloolik, Nunavut, Canada
| | - Steven H Ferguson
- Fisheries and Oceans Canada, Central and Arctic Region, Winnipeg, Manitoba, Canada
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Jagielski PM, Dey CJ, Gilchrist HG, Richardson ES, Semeniuk CA. Polar bear foraging on common eider eggs: estimating the energetic consequences of a climate-mediated behavioural shift. Anim Behav 2021. [DOI: 10.1016/j.anbehav.2020.11.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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Viengkone M, Derocher AE, Richardson ES, Obbard ME, Dyck MG, Lunn NJ, Sahanatien V, Robinson BG, Davis CS. Assessing spatial discreteness of Hudson Bay polar bear populations using telemetry and genetics. Ecosphere 2018. [DOI: 10.1002/ecs2.2364] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Affiliation(s)
- Michelle Viengkone
- Department of Biological Sciences; University of Alberta; Edmonton Alberta T6G 2E9 Canada
| | - Andrew E. Derocher
- Department of Biological Sciences; University of Alberta; Edmonton Alberta T6G 2E9 Canada
| | - Evan S. Richardson
- Wildlife Research Division, Science and Technology Branch; Environment and Climate Change Canada; Biological Sciences Building; University of Alberta; Edmonton Alberta T6G 2E9 Canada
| | - Martyn E. Obbard
- Wildlife Research and Monitoring Section; Ontario Ministry of Natural Resources and Forestry; Trent University; Peterborough Ontario K9J 7B8 Canada
| | - Markus G. Dyck
- Department of Environment; Government of Nunavut; Igloolik Nunavut X0A 0L0 Canada
| | - Nicholas J. Lunn
- Wildlife Research Division, Science and Technology Branch; Environment and Climate Change Canada; Biological Sciences Building; University of Alberta; Edmonton Alberta T6G 2E9 Canada
| | - Vicki Sahanatien
- Department of Biological Sciences; University of Alberta; Edmonton Alberta T6G 2E9 Canada
| | - Barry G. Robinson
- Department of Biological Sciences; University of Alberta; Edmonton Alberta T6G 2E9 Canada
| | - Corey S. Davis
- Department of Biological Sciences; University of Alberta; Edmonton Alberta T6G 2E9 Canada
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Wilson RR, Regehr EV, Rode KD, St Martin M. Invariant polar bear habitat selection during a period of sea ice loss. Proc Biol Sci 2017; 283:rspb.2016.0380. [PMID: 27534959 DOI: 10.1098/rspb.2016.0380] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Accepted: 07/26/2016] [Indexed: 11/12/2022] Open
Abstract
Climate change is expected to alter many species' habitat. A species' ability to adjust to these changes is partially determined by their ability to adjust habitat selection preferences to new environmental conditions. Sea ice loss has forced polar bears (Ursus maritimus) to spend longer periods annually over less productive waters, which may be a primary driver of population declines. A negative population response to greater time spent over less productive water implies, however, that prey are not also shifting their space use in response to sea ice loss. We show that polar bear habitat selection in the Chukchi Sea has not changed between periods before and after significant sea ice loss, leading to a 75% reduction of highly selected habitat in summer. Summer was the only period with loss of highly selected habitat, supporting the contention that summer will be a critical period for polar bears as sea ice loss continues. Our results indicate that bears are either unable to shift selection patterns to reflect new prey use patterns or that there has not been a shift towards polar basin waters becoming more productive for prey. Continued sea ice loss is likely to further reduce habitat with population-level consequences for polar bears.
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Affiliation(s)
- Ryan R Wilson
- US Fish and Wildlife Service, 1011 E Tudor Road, Anchorage, AK 99503, USA
| | - Eric V Regehr
- US Fish and Wildlife Service, 1011 E Tudor Road, Anchorage, AK 99503, USA
| | - Karyn D Rode
- US Geological Survey, Alaska Science Center, 4210 University Drive, Anchorage, AK 99508, USA
| | - Michelle St Martin
- US Fish and Wildlife Service, 1011 E Tudor Road, Anchorage, AK 99503, USA
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Viengkone M, Derocher AE, Richardson ES, Malenfant RM, Miller JM, Obbard ME, Dyck MG, Lunn NJ, Sahanatien V, Davis CS. Assessing polar bear ( Ursus maritimus) population structure in the Hudson Bay region using SNPs. Ecol Evol 2016; 6:8474-8484. [PMID: 28031799 PMCID: PMC5167041 DOI: 10.1002/ece3.2563] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2015] [Revised: 09/14/2016] [Accepted: 09/20/2016] [Indexed: 12/28/2022] Open
Abstract
Defining subpopulations using genetics has traditionally used data from microsatellite markers to investigate population structure; however, single‐nucleotide polymorphisms (SNPs) have emerged as a tool for detection of fine‐scale structure. In Hudson Bay, Canada, three polar bear (Ursus maritimus) subpopulations (Foxe Basin (FB), Southern Hudson Bay (SH), and Western Hudson Bay (WH)) have been delineated based on mark–recapture studies, radiotelemetry and satellite telemetry, return of marked animals in the subsistence harvest, and population genetics using microsatellites. We used SNPs to detect fine‐scale population structure in polar bears from the Hudson Bay region and compared our results to the current designations using 414 individuals genotyped at 2,603 SNPs. Analyses based on discriminant analysis of principal components (DAPC) and STRUCTURE support the presence of four genetic clusters: (i) Western—including individuals sampled in WH, SH (excluding Akimiski Island in James Bay), and southern FB (south of Southampton Island); (ii) Northern—individuals sampled in northern FB (Baffin Island) and Davis Strait (DS) (Labrador coast); (iii) Southeast—individuals from SH (Akimiski Island in James Bay); and (iv) Northeast—individuals from DS (Baffin Island). Population structure differed from microsatellite studies and current management designations demonstrating the value of using SNPs for fine‐scale population delineation in polar bears.
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Affiliation(s)
- Michelle Viengkone
- Department of Biological Sciences University of Alberta Edmonton AB Canada
| | | | - Evan Shaun Richardson
- Wildlife Research Division Science and Technology Branch Environment and Climate Change Canada University of Alberta Edmonton AB Canada
| | - René Michael Malenfant
- Department of Biological Sciences University of Alberta Edmonton AB Canada; Department of Biology University of New Brunswick Fredericton NB Canada
| | - Joshua Moses Miller
- Department of Biological Sciences University of Alberta Edmonton AB Canada; Department of Ecology and Evolutionary Biology Yale University New Haven CT USA
| | - Martyn E Obbard
- Wildlife Research and Monitoring Section Ontario Ministry of Natural Resources and Forestry Trent University Peterborough ON Canada
| | - Markus G Dyck
- Department of Environment Government of Nunavut Igloolik NU Canada
| | - Nick J Lunn
- Wildlife Research Division Science and Technology Branch Environment and Climate Change Canada University of Alberta Edmonton AB Canada
| | - Vicki Sahanatien
- Department of Biological Sciences University of Alberta Edmonton AB Canada
| | - Corey S Davis
- Department of Biological Sciences University of Alberta Edmonton AB Canada
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Cherry SG, Derocher AE, Lunn NJ. Habitat-mediated timing of migration in polar bears: an individual perspective. Ecol Evol 2016; 6:5032-42. [PMID: 27547331 PMCID: PMC4979725 DOI: 10.1002/ece3.2233] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Revised: 05/12/2016] [Accepted: 05/16/2016] [Indexed: 11/27/2022] Open
Abstract
Migration phenology is largely determined by how animals respond to seasonal changes in environmental conditions. Our perception of the relationship between migratory behavior and environmental cues can vary depending on the spatial scale at which these interactions are measured. Understanding the behavioral mechanisms behind population‐scale movements requires knowledge of how individuals respond to local cues. We show how time‐to‐event models can be used to predict what factors are associated with the timing of an individual's migratory behavior using data from GPS collared polar bears (Ursus maritimus) that move seasonally between sea ice and terrestrial habitats. We found the concentration of sea ice that bears experience at a local level, along with the duration of exposure to these conditions, was most associated with individual migration timing. Our results corroborate studies that assume thresholds of >50% sea ice concentration are necessary for suitable polar bear habitat; however, continued periods (e.g., days to weeks) of exposure to suboptimal ice concentrations during seasonal melting were required before the proportion of bears migrating to land increased substantially. Time‐to‐event models are advantageous for examining individual movement patterns because they account for the idea that animals make decisions based on an accumulation of knowledge from the landscapes they move through and not simply the environment they are exposed to at the time of a decision. Understanding the migration behavior of polar bears moving between terrestrial and marine habitat, at multiple spatiotemporal scales, will be a major aspect of quantifying observed and potential demographic responses to climate‐induced environmental changes.
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Affiliation(s)
- Seth G Cherry
- Department of Biological Sciences University of Alberta Edmonton AB T6G 2E9 Canada
| | - Andrew E Derocher
- Department of Biological Sciences University of Alberta Edmonton AB T6G 2E9 Canada
| | - Nicholas J Lunn
- Environment and Climate Change Canada University of Alberta CW405 Biological Sciences Building Edmonton AB T6G 2E9 Canada
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Galicia MP, Thiemann GW, Dyck MG, Ferguson SH, Higdon JW. Dietary habits of polar bears in Foxe Basin, Canada: possible evidence of a trophic regime shift mediated by a new top predator. Ecol Evol 2016; 6:6005-18. [PMID: 27547372 PMCID: PMC4983609 DOI: 10.1002/ece3.2173] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Revised: 04/05/2016] [Accepted: 04/13/2016] [Indexed: 11/09/2022] Open
Abstract
Polar bear (Ursus maritimus) subpopulations in several areas with seasonal sea ice regimes have shown declines in body condition, reproductive rates, or abundance as a result of declining sea ice habitat. In the Foxe Basin region of Nunavut, Canada, the size of the polar bear subpopulation has remained largely stable over the past 20 years, despite concurrent declines in sea ice habitat. We used fatty acid analysis to examine polar bear feeding habits in Foxe Basin and thus potentially identify ecological factors contributing to population stability. Adipose tissue samples were collected from 103 polar bears harvested during 2010-2012. Polar bear diet composition varied spatially within the region with ringed seal (Pusa hispida) comprising the primary prey in northern and southern Foxe Basin, whereas polar bears in Hudson Strait consumed equal proportions of ringed seal and harp seal (Pagophilus groenlandicus). Walrus (Odobenus rosmarus) consumption was highest in northern Foxe Basin, a trend driven by the ability of adult male bears to capture large-bodied prey. Importantly, bowhead whale (Balaena mysticetus) contributed to polar bear diets in all areas and all age and sex classes. Bowhead carcasses resulting from killer whale (Orcinus orca) predation and subsistence harvest potentially provide an important supplementary food source for polar bears during the ice-free period. Our results suggest that the increasing abundance of killer whales and bowhead whales in the region could be indirectly contributing to improved polar bear foraging success despite declining sea ice habitat. However, this indirect interaction between top predators may be temporary if continued sea ice declines eventually severely limit on-ice feeding opportunities for polar bears.
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Affiliation(s)
- Melissa P Galicia
- Department of Biology York University Toronto Ontario M3J 1P3 Canada
| | - Gregory W Thiemann
- Faculty of Environmental Studies York University Toronto Ontario M3J 1P3 Canada
| | - Markus G Dyck
- Wildlife Research Section Department of Environment Government of Nunavut P.O. Box 209 Igloolik Nunavut X0A 0L0 Canada
| | - Steven H Ferguson
- Fisheries and Oceans Canada 501 University Crescent Winnipeg Manitoba R3T 2N6 Canada
| | - Jeff W Higdon
- Higdon Wildlife Consulting 912 Ashburn Street Winnipeg Manitoba R3G 3C9 Canada
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