Polar bear denning distribution in the Canadian Arctic

Florko, Katie R. N.; Derocher, Andrew E.; Breiter, C-Jae C.; Ghazal, Maha; Hedman, Daryll; Higdon, Jeff W.; Richardson, Evan S.; Sahanatien, Vicki; Trim, Vicki; Petersen, Stephen D.

doi:10.1007/s00300-020-02657-8

Cited by 13 publications

(9 citation statements)

References 38 publications

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“…Tagging was performed primarily in the Western Hudson Bay polar bears’ summering and denning grounds in Wapusk National Park, Manitoba (Fig. 2 ; [ 43 , 126 , 139 ]). To determine age, a vestigial premolar was extracted from each bear whose age was unknown (i.e., bears years that were not previously captured), and age was determined by counting annuli in the cementum [ 19 ].…”

Section: Methodsmentioning

confidence: 99%

Drivers of polar bear behavior and the possible effects of prey availability on foraging strategy

et al. 2022

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Background Change in behavior is one of the earliest responses to variation in habitat suitability. It is therefore important to understand the conditions that promote different behaviors, particularly in areas undergoing environmental change. Animal movement is tightly linked to behavior and remote tracking can be used to study ethology when direct observation is not possible. Methods We used movement data from 14 polar bears (Ursus maritimus) in Hudson Bay, Canada, during the foraging season (January–June), when bears inhabit the sea ice. We developed an error-tolerant method to correct for sea ice drift in tracking data. Next, we used hidden Markov models with movement and orientation relative to wind to study three behaviors (stationary, area-restricted search, and olfactory search) and examine effects of 11 covariates on behavior. Results Polar bears spent approximately 47% of their time in the stationary drift state, 29% in olfactory search, and 24% in area-restricted search. High energy behaviors occurred later in the day (around 20:00) compared to other populations. Second, olfactory search increased as the season progressed, which may reflect a shift in foraging strategy from still-hunting to active search linked to a shift in seal availability (i.e., increase in haul-outs from winter to the spring pupping and molting seasons). Last, we found spatial patterns of distribution linked to season, ice concentration, and bear age that may be tied to habitat quality and competitive exclusion. Conclusions Our observations were generally consistent with predictions of the marginal value theorem, and differences between our findings and other populations could be explained by regional or temporal variation in resource availability. Our novel movement analyses and finding can help identify periods, regions, and conditions of critical habitat.

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Section: Methodsmentioning

confidence: 99%

Drivers of polar bear behavior and the possible effects of prey availability on foraging strategy

et al. 2022

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“…Most polar bear subpopulations den near the interface between sea ice and land, although some den further inland (Florko et al, 2020). Some den on ice flows (Lentfer, 1975).…”

Section: Polar Bear Movement To Landmentioning

confidence: 99%

Contribution of hybridization between polar bears and grizzly bears to polar bear extinction

Shafer

2023

Wildlife Letters

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This review explores whether recent hybridization events between polar bears (Ursus maritimus) and grizzly bears (Ursus arctos horribilis) will eventually contribute to the extinction of the modern polar bear. In April 2006, genetic analysis of an odd‐looking bear killed in the Northwest Territories, Canada, revealed this specimen to be a polar bear–grizzly bear hybrid, and additional hybrid bears were harvested beginning in April 2010. These events have been sensationalized by some in the media, who have speculated that the modern polar bear may become extinct due to crossbreeding with grizzly bears. Although studies support the introgression of brown bear genes into the polar bear genome during the Pleistocene, no evidence supports the occurrence of a similar event today. Even if such an introgression event occurred, hybrids evolving rapidly enough to adapt to ongoing sea ice depletion is not scientifically plausible. The loss of genetic integrity and modified morphology due to inbreeding between polar bears and grizzly bears are not considered threats to polar bear survival. As many scientists have stressed for decades, the greatest threat to the survival of the modern polar bear is sea ice depletion due to climate change.

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“…In a recent study, Larson and colleagues (2020) discovered that overall, denning polar bears are quite tolerant of human disturbance; however, the degree of tolerance is dependent on the disturbance stimuli (e.g., machinery vs humans on foot) and its distance from the den. Locating polar bear denning sites will be informative in guiding management decisions in an increasingly human-occupied Arctic (Florko et al 2020). Once dens are discovered, monitoring den sites will aid in understanding how bears respond to den abandonment near human occupied areas.…”

Section: Den Site Locationmentioning

confidence: 99%

The utility of drones for studying polar bear behaviour in the Canadian Arctic: opportunities and recommendations

et al. 2022

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Climate-induced sea-ice loss represents the greatest threat to polar bears (Ursus maritimus), and utilizing drones to characterize behavioural responses to sea-ice loss is valuable to forecasting polar bear persistence. In this manuscript, we review previously published literature and draw on our own experience of using multirotor aerial drones to study polar bear behaviour in the Canadian Arctic. Specifically, we suggest that drones can minimize human-bear conflicts by allowing users to observe bears from a safe vantage point; produce high-quality behavioural data that can be reviewed as many times as needed and shared with multiple stakeholders; and foster knowledge generation through co-production with northern communities. We posit that in some instances drones may be considered as an alternative tool for studying polar bear foraging behaviour, interspecific interactions, human-bear interactions, human safety and conflict mitigation, and den-site location at individual-level, small spatial scales. Finally, we discuss flying techniques to ensure ethical operation around polar bears, regulatory requirements to consider, and recommend that future research focus on understanding polar bears’ behavioural and physiological responses to drones and the efficacy of drones as a deterrent tool for safety purposes.

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Polar bear denning distribution in the Canadian Arctic

Cited by 13 publications

References 38 publications

Drivers of polar bear behavior and the possible effects of prey availability on foraging strategy

Drivers of polar bear behavior and the possible effects of prey availability on foraging strategy

Contribution of hybridization between polar bears and grizzly bears to polar bear extinction

The utility of drones for studying polar bear behaviour in the Canadian Arctic: opportunities and recommendations

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