Assessing spatial discreteness of Hudson Bay polar bear populations using telemetry and genetics

Viengkone, Michelle; Derocher, Andrew E.; Richardson, Evan S.; Obbard, Martyn E.; Dyck, Markus; Lunn, Nicholas J.; Sahanatien, Vicki; Robinson, Barry G.; Davis, Corey S.

doi:10.1002/ecs2.2364

Cited by 8 publications

(6 citation statements)

References 61 publications

(120 reference statements)

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“…Overall, however, spatial isotopic structure in hair generally did not match the current subpopulation boundaries well. A similar result was found for the geographic variation in genetic structure of the Canadian polar bear population 19 . In contrast to the current management boundaries, this interpolation of isotopic data provides an ecologically-based spatial approach to define subpopulations by identifying geographically explicit, isotopically distinct clusters.…”

Section: Resultssupporting

confidence: 83%

Geographical assignment of polar bears using multi-element isoscapes

Koehler

Kardynal

Hobson

2019

Sci Rep

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Wide-ranging apex predators are among the most challenging of all fauna to conserve and manage. This is especially true of the polar bear ( Ursus maritimus ), an iconic predator that is hunted in Canada and threatened by global climate change. We used combinations of stable isotopes ( 13 C, 15 N, 2 H, 18 O) in polar bear hair from > 1000 individuals, sampled from across much of the Canadian Arctic and sub-Arctic, to test the ability of stable isotopic profiles to ‘assign’ bears to (1) predefined managed subpopulations, (2) subpopulations defined by similarities in stable isotope values using quadratic discriminant analysis, and (3) spatially explicit, isotopically distinct clusters derived from interpolated (i.e. ‘kriged’) isotopic landscapes, or ‘isoscapes’, using the partitioning around medoids algorithm. A four-isotope solution provided the highest overall assignment accuracies (~80%) to pre-existing management subpopulations with accuracy rates ranging from ~30–99% (median = 64%). Assignment accuracies of bears to hierarchically clustered ecological groups based on isotopes ranged from ~64–99%. Multivariate assignment to isotopic clusters resulted in highest assignment accuracies of 68% (33–77%), 84% (47–96%) and 74% (53–85%) using two, three and four stable isotope groups, respectively. The resulting spatial structure inherent in the multiple stable isotopic compositions of polar bear tissues is a powerful forensic tool that will, in this case, contribute to the conservation and management of this species. Currently, it is unclear what is driving these robust isotopic patterns and future research is needed to evaluate the processes behind the pattern. Nonetheless, our isotopic approach can be further applied to other apex mammalian predators under threat, such as the large felids, providing that isotopic structure occurs throughout their range.

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Section: Resultssupporting

confidence: 83%

Geographical assignment of polar bears using multi-element isoscapes

Koehler

Kardynal

Hobson

2019

Sci Rep

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“…Three subpopulations of polar bears occur in Hudson Bay: Foxe Basin, Southern Hudson Bay, and Western Hudson Bay (Peacock, Derocher, Lunn, & Obbard, 2010). During the ice‐free period, these subpopulations are largely segregated from one another due to strong, seasonal fidelity to traditional summering areas but do overlap to some degree on the sea ice during winter and spring (Derocher & Stirling, 1990; Peacock et al., 2010; Stirling, Lunn, Iacozza, Elliott, & Obbard, 2004; Viengkone et al., 2018). The Western Hudson Bay subpopulation has experienced declines in body condition, survival, and reproduction from 1984 to 2004 owing to lengthening ice‐free seasons resulting in ~22% decline in population size (Regehr, Lunn, Amstrup, & Stirling, 2007).…”

Section: Methodsmentioning

confidence: 99%

The stress of Arctic warming on polar bears

Boonstra

Bodner

Bosson

et al. 2020

Global Change Biology

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Arctic ecosystems are changing rapidly in response to climate warming. While Arctic mammals are highly evolved to these extreme environments, particularly with respect to their stress axis, some species may have limited capacity to adapt to this change. We examined changes in key components of the stress axis (cortisol and its carrier protein—corticosteroid binding globulin [CBG]) in polar bears (Ursus maritimus) from western Hudson Bay (N = 300) over a 33 year period (1983–2015) during which time the ice‐free period was increasing. Changing sea ice phenology limits spring hunting opportunities and extends the period of onshore fasting. We assessed the response of polar bears to a standardized stressor (helicopter pursuit, darting, and immobilization) during their onshore fasting period (late summer–autumn) and quantified the serum levels of the maximum corticosteroid binding capacity (MCBC) of CBG, the serum protein that binds cortisol strongly, and free cortisol (FC). We quantified bear condition (age, sex, female with cubs or not, fat condition), sea ice (breakup in spring–summer, 1 year lagged freeze‐up in autumn), and duration of fasting until sample collection as well as cumulative impacts of the latter environmental traits from the previous year. Data were separated into “good” years (1983–1990) when conditions were thought to be optimal and “poor” years (1991–2015) when sea ice conditions deteriorated and fasting on land was extended. MCBC explained 39.4% of the variation in the good years, but only 28.1% in the poor ones, using both biological and environmental variables. MCBC levels decreased with age. Changes in FC were complex, but more poorly explained. Counterintuitively, MCBC levels increased with increased time onshore, 1 year lag effects, and in poor ice years. We conclude that MCBC is a biomarker of stress in polar bears and that the changes we document are a consequence of climate warming.

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“…‘latent factor mixed models’, Frichot et al, 2013; and ‘redundancy analysis’, Kierepka & Latch, 2015), and advances are being made in integrating genetic data with acoustic, satellite telemetry and stable isotopes (e.g. Townsend et al, 2018; Viengkone et al, 2018; Sremba et al, 2019; Montanari, Kershaw & Rosenbaum, 2020). The advancement of these often‐complex analytical approaches should occur in parallel with the development of communication strategies to support the interpretation of analytical methods, results, and conservation applications by non‐specialists.…”

Section: Discussionmentioning

confidence: 99%

Geospatial genetics: Integrating genetics into marine protection and spatial planning

Kershaw

McClintock

Andrews

et al. 2021

Aquatic Conservation

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The protection of evolutionary processes and maintenance of genetic diversity is necessary for the persistence of biodiversity and ecosystem resilience. The importance of genetic diversity has been reflected in a range of marine policy mechanisms, and the genetic ‘toolbox’ has great potential to support marine protection and marine spatial planning (MSP) at multiple scales. Despite scientific advances in the application of genetics in marine protection and management, systematic integration of genetic information has been generally lacking, primarily due to a knowledge and communication disconnect between geneticists and the marine policy and management community. To meet these outstanding needs, a ‘geospatial genetics’ approach to spatially map species‐specific genetic data and associated information in a way that can be readily integrated by practitioners into marine protection and MSP decisions was developed. Techniques to derive geospatial genetic data layers, which can be viewed and mapped alongside other kinds of spatial data commonly used by conservation practitioners, hold promise for increasing the accessibility of genetic data to support policy decisions more fully. While applicable to many mobile and sessile taxa, an initial focus was placed on marine mammals, and the approach was developed and refined through a series of international meetings and published papers, as well as the development of interactive, expert‐reviewed case studies hosted on the MSP tool SeaSketch. Outcomes of the work to date are currently serving in the policy arena by informing the identification of Important Marine Mammal Areas, an initiative led by the IUCN Marine Mammal Protected Areas Task Force to apply criteria to identify marine mammal habitats across the world's ocean, seas and relevant inland waters through a standardized process. It has become clear that geospatial genetics has great potential to foster increased collaboration among an intersectional community of geneticists, spatial ecologists, and practitioners. This increased opportunity for dialogue and cooperation will help ensure that evolutionary processes are factored into marine protection and MSP processes, and potentially for freshwater and terrestrial systems.

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Assessing spatial discreteness of Hudson Bay polar bear populations using telemetry and genetics

Cited by 8 publications

References 61 publications

Geographical assignment of polar bears using multi-element isoscapes

Geographical assignment of polar bears using multi-element isoscapes

The stress of Arctic warming on polar bears

Geospatial genetics: Integrating genetics into marine protection and spatial planning

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