Females roam while males patrol: divergence in breeding season movements of pack-ice polar bears (
            <i>Ursus maritimus</i>
            )

Laidre, Kristin L.; Born, Erik W.; Gurarie, Eliezer; Wiig, Øystein; Dietz, Runé; Stern, Harry L.

doi:10.1098/rspb.2012.2371

Cited by 73 publications

(70 citation statements)

References 45 publications

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“…Our analyses, which also included harvest recoveries of both sexes, did not indicate vastly different movement between males and females. Previous studies in BB also indicated that both sexes utilize the same habitats in spring (Laidre et al., 2013). We therefore suggest our satellite telemetry data are a representative index of broad population movement patterns.…”

Section: Discussionmentioning

confidence: 99%

Range contraction and increasing isolation of a polar bear subpopulation in an era of sea‐ice loss

Laidre

Born

Atkinson

et al. 2018

Ecology and Evolution

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Climate change is expected to result in range shifts and habitat fragmentation for many species. In the Arctic, loss of sea ice will reduce barriers to dispersal or eliminate movement corridors, resulting in increased connectivity or geographic isolation with sweeping implications for conservation. We used satellite telemetry, data from individually marked animals (research and harvest), and microsatellite genetic data to examine changes in geographic range, emigration, and interpopulation connectivity of the Baffin Bay (BB) polar bear (Ursus maritimus) subpopulation over a 25‐year period of sea‐ice loss. Satellite telemetry collected from n = 43 (1991–1995) and 38 (2009–2015) adult females revealed a significant contraction in subpopulation range size (95% bivariate normal kernel range) in most months and seasons, with the most marked reduction being a 70% decline in summer from 716,000 km2 (SE 58,000) to 211,000 km2 (SE 23,000) (p < .001). Between the 1990s and 2000s, there was a significant shift northward during the on‐ice seasons (2.6° shift in winter median latitude, 1.1° shift in spring median latitude) and a significant range contraction in the ice‐free summers. Bears in the 2000s were less likely to leave BB, with significant reductions in the numbers of bears moving into Davis Strait (DS) in winter and Lancaster Sound (LS) in summer. Harvest recoveries suggested both short and long‐term fidelity to BB remained high over both periods (83–99% of marked bears remained in BB). Genetic analyses using eight polymorphic microsatellites confirmed a previously documented differentiation between BB, DS, and LS; yet weakly differentiated BB from Kane Basin (KB) for the first time. Our results provide the first multiple lines of evidence for an increasingly geographically and functionally isolated subpopulation of polar bears in the context of long‐term sea‐ice loss. This may be indicative of future patterns for other polar bear subpopulations under climate change.

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Section: Discussionmentioning

confidence: 99%

Range contraction and increasing isolation of a polar bear subpopulation in an era of sea‐ice loss

Laidre

Born

Atkinson

et al. 2018

Ecology and Evolution

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“…We estimated that females traveled 51.6 AE 47.0 (SD) km over a 7 day period (n = 13,241 movement measurements). Collar-based movement data were not available for males in this region, but Laidre et al (2012) found no difference in movement rates of males and females in the spring.…”

Section: Objective 1: Spatial and Temporal Variation In Fasting Behmentioning

confidence: 99%

Spring fasting behavior in a marine apex predator provides an index of ecosystem productivity

Rode

Wilson

Douglas

et al. 2017

Global Change Biology

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The effects of declining Arctic sea ice on local ecosystem productivity are not well understood but have been shown to vary inter-specifically, spatially, and temporally.Because marine mammals occupy upper trophic levels in Arctic food webs, they may be useful indicators for understanding variation in ecosystem productivity. Polar bears (Ursus maritimus) are apex predators that primarily consume benthic and pelagic-feeding ice-associated seals. As such, their productivity integrates sea ice conditions and the ecosystem supporting them. Declining sea ice availability has been linked to negative population effects for polar bears but does not fully explain observed population changes. We examined relationships between spring foraging success of polar bears and sea ice conditions, prey productivity, and general patterns of ecosystem productivity in the Beaufort and Chukchi Seas (CSs). Fasting status (≥7 days) was estimated using serum urea and creatinine levels of 1,448 samples collected from 1,177 adult and subadult bears across three subpopulations. Fasting increased in the Beaufort Sea between 1983-1999 and 2000-2016 and was related to an index of ringed seal body condition.This change was concurrent with declines in body condition of polar bears and observed changes in the diet, condition and/or reproduction of four other vertebrate consumers within the food chain. In contrast, fasting declined in CS polar bears between periods and was less common than in the two Beaufort Sea subpopulations consistent with studies demonstrating higher primary productivity and maintenance or improved body condition in polar bears, ringed seals, and bearded seals despite recent sea ice loss in this region. Consistency between regional and temporal variation in spring polar bear fasting and food web productivity suggests that polar bears may be a useful indicator species. Furthermore, our results suggest that spatial and temporal ecological variation is important in affecting upper trophic-level productivity in these marine ecosystems.

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“…Our approach assumes that our sample of adult female movements is also representative of male movements. While not specifically addressed for polar bears in our study region, Laidre et al (2013) found that males and females of two separate polar bear populations exhibited similar habitat selection patterns and 4- Fig. 3.…”

Section: Discussionmentioning

confidence: 98%

Potential impacts of offshore oil spills on polar bears in the Chukchi Sea

Wilson

Perham

French-McCay

et al. 2018

Environmental Pollution

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a b s t r a c tSea ice decline is anticipated to increase human access to the Arctic Ocean allowing for offshore oil and gas development in once inaccessible areas. Given the potential negative consequences of an oil spill on marine wildlife populations in the Arctic, it is important to understand the magnitude of impact a large spill could have on wildlife to inform response planning efforts. In this study we simulated oil spills that released 25,000 barrels of oil for 30 days in autumn originating from two sites in the Chukchi Sea (one in Russia and one in the U.S.) and tracked the distribution of oil for 76 days. We then determined the potential impact such a spill might have on polar bears (Ursus maritimus) and their habitat by overlapping spills with maps of polar bear habitat and movement trajectories. Only a small proportion (1 e10%) of high-value polar bear sea ice habitat was directly affected by oil sufficient to impact bears. However, 27e38% of polar bears in the region were potentially exposed to oil. Oil consistently had the highest probability of reaching Wrangel and Herald islands, important areas of denning and summer terrestrial habitat. Oil did not reach polar bears until approximately 3 weeks after the spills. Our study found the potential for significant impacts to polar bears under a worst case discharge scenario, but suggests that there is a window of time where effective containment efforts could minimize exposure to bears. Our study provides a framework for wildlife managers and planners to assess the level of response that would be required to treat exposed wildlife and where spill response equipment might be best stationed. While the size of spill we simulated has a low probability of occurring, it provides an upper limit for planners to consider when crafting response plans.Published by Elsevier Ltd.

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Females roam while males patrol: divergence in breeding season movements of pack-ice polar bears ( Ursus maritimus )

Cited by 73 publications

References 45 publications

Range contraction and increasing isolation of a polar bear subpopulation in an era of sea‐ice loss

Range contraction and increasing isolation of a polar bear subpopulation in an era of sea‐ice loss

Spring fasting behavior in a marine apex predator provides an index of ecosystem productivity

Potential impacts of offshore oil spills on polar bears in the Chukchi Sea

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