Ursus maritimus
View article
Beyond the obvious: Environmental health implications of polar polycyclic aromatic hydrocarbons Open
The genotoxic, mutagenic and carcinogenic effects of polar polycyclic aromatic hydrocarbons (polar PAHs) are believed to surpass those of their parent PAHs; however, their environmental and human health implications have been largely unexp…
View article
Sea-ice indicators of polar bear habitat Open
Nineteen subpopulations of polar bears (Ursus maritimus) are found throughout the circumpolar Arctic, and in all regions they depend on sea ice as a platform for traveling, hunting, and breeding. Therefore polar bear phenology – the cycle …
View article
High-energy, high-fat lifestyle challenges an Arctic apex predator, the polar bear Open
A demanding lifestyle Polar bears appear to be well adapted to the extreme conditions of their Arctic habitat. Pagano et al. , however, show that the energy balance in this harsh environment is narrower than we might expect (see the Perspe…
View article
Climate change and the increasing impact of polar bears on bird populations Open
The Arctic is becoming warmer at a high rate, and contractions in the extent of sea ice are currently changing the habitats of marine top-predators dependent on ice. Polar bears (Ursus maritimus) depend on sea ice for hunting seals. For th…
View article
Can polar bears use terrestrial foods to offset lost ice‐based hunting opportunities? Open
Increased land use by polar bears ( Ursus maritimus ) due to climate‐change‐induced reduction of their sea‐ice habitat illustrates the impact of climate change on species distributions and the difficulty of conserving a large, highly speci…
View article
Rapid Environmental Change Drives Increased Land Use by an Arctic Marine Predator Open
In the Arctic Ocean's southern Beaufort Sea (SB), the length of the sea ice melt season (i.e., period between the onset of sea ice break-up in summer and freeze-up in fall) has increased substantially since the late 1990s. Historically, po…
View article
Increased Land Use by Chukchi Sea Polar Bears in Relation to Changing Sea Ice Conditions Open
Recent observations suggest that polar bears (Ursus maritimus) are increasingly using land habitats in some parts of their range, where they have minimal access to their preferred prey, likely in response to loss of their sea ice habitat a…
View article
Conservation status of polar bears (<i>Ursus maritimus</i>) in relation to projected sea-ice declines Open
Loss of Arctic sea ice owing to climate change is the primary threat to polar bears throughout their range. We evaluated the potential response of polar bears to sea-ice declines by (i) calculating generation length (GL) for the species, w…
View article
Forecasting the relative influence of environmental and anthropogenic stressors on polar bears Open
Effective conservation planning requires understanding and ranking threats to wildlife populations. We developed a Bayesian network model to evaluate the relative influence of environmental and anthropogenic stressors, and their mitigation…
View article
Trends in body condition in polar bears (<i>Ursus maritimus</i>) from the Southern Hudson Bay subpopulation in relation to changes in sea ice Open
Sea ice is declining over much of the Arctic. In Hudson Bay the ice melts completely each summer, and advances in break-up have resulted in longer ice-free seasons. Consequently, earlier break-up is implicated in declines in body condition…
View article
Genomic Evidence of Widespread Admixture from Polar Bears into Brown Bears during the Last Ice Age Open
Recent genomic analyses have provided substantial evidence for past periods of gene flow from polar bears (Ursus maritimus) into Alaskan brown bears (Ursus arctos), with some analyses suggesting a link between climate change and genomic in…
View article
An Arctic predator–prey system in flux: climate change impacts on coastal space use by polar bears and ringed seals Open
Summary Climate change is impacting different species at different rates, leading to alterations in biological interactions with ramifications for wider ecosystem functioning. Understanding these alterations can help improve predictive cap…
View article
Anthropogenic flank attack on polar bears: interacting consequences of climate warming and pollutant exposure Open
Polar bears (Ursus maritimus) are subjected to several anthropogenic threats, climate warming and exposure to pollutants being two of these. For polar bears, one of the main effects of climate warming is limited access to prey, due to loss…
View article
Harvesting wildlife affected by climate change: a modelling and management approach for polar bears Open
Summary The conservation of many wildlife species requires understanding the demographic effects of climate change, including interactions between climate change and harvest, which can provide cultural, nutritional or economic value to hum…
View article
Polar bear–grizzly bear interactions during the autumn open-water period in Alaska Open
Reduction of summer sea ice extent has led some polar bear (Ursus maritimus) populations to increase their use of land during the summer/autumn open-water period. While terrestrial food resources are generally not sufficient to compensate …
View article
Invariant polar bear habitat selection during a period of sea ice loss Open
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 for…
View article
The number and distribution of polar bears in the western Barents Sea Open
Polar bears have experienced a rapid loss of sea-ice habitat in the Barents Sea. Monitoring this subpopulation focuses on the effects on polar bear demography. In August 2015, we conducted a survey in the Norwegian Arctic to estimate polar…
View article
Interrelated ecological impacts of climate change on an apex predator Open
Climate change has broad ecological implications for species that rely on sensitive habitats. For some top predators, loss of habitat is expected to lead to cascading behavioral, nutritional, and reproductive changes that ultimately accele…
View article
Energetic costs of locomotion in bears: is plantigrade locomotion energetically economical? Open
Ursids are the largest mammals to retain a plantigrade posture. This primitive posture has been proposed to result in reduced locomotor speed and economy relative to digitigrade and unguligrade species, particularly at high speeds. Previou…
View article
Re-assessing abundance of Southern Hudson Bay polar bears by aerial survey: effects of climate change at the southern edge of the range Open
The Southern Hudson Bay polar bear (Ursus maritimus Phipps, 1774) subpopulation is considered stable, but conflicting evidence lends uncertainty to that designation. Capture–recapture studies conducted in 1984–1986 and 2003–2005 and an aer…
View article
Dietary habits of polar bears in Foxe Basin, Canada: possible evidence of a trophic regime shift mediated by a new top predator Open
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 Nuna…
View article
Assessing polar bear (<i>Ursus maritimus</i>) population structure in the Hudson Bay region using <span>SNP</span>s Open
Defining subpopulations using genetics has traditionally used data from microsatellite markers to investigate population structure; however, single‐nucleotide polymorphisms ( SNP s) have emerged as a tool for detection of fine‐scale struct…
View article
Estimating the energy expenditure of free‐ranging polar bears using tri‐axial accelerometers: A validation with doubly labeled water Open
Measures of energy expenditure can be used to inform animal conservation and management, but methods for measuring the energy expenditure of free‐ranging animals have a variety of limitations. Advancements in biologging technologies have e…
View article
Circumpolar Genetic Structure and Recent Gene Flow of Polar Bears: A Reanalysis Open
Recently, an extensive study of 2,748 polar bears (Ursus maritimus) from across their circumpolar range was published in PLOS ONE, which used microsatellites and mitochondrial haplotypes to apparently show altered population structure and …
View article
High contributions of sea ice derived carbon in polar bear (Ursus maritimus) tissue Open
Polar bears (Ursus maritimus) rely upon Arctic sea ice as a physical habitat. Consequently, conservation assessments of polar bears identify the ongoing reduction in sea ice to represent a significant threat to their survival. However, the…
View article
Implications of the Circumpolar Genetic Structure of Polar Bears for Their Conservation in a Rapidly Warming Arctic Open
We provide an expansive analysis of polar bear (Ursus maritimus) circumpolar genetic variation during the last two decades of decline in their sea-ice habitat. We sought to evaluate whether their genetic diversity and structure have change…
View article
Temporal complexity of southern<span>B</span>eaufort<span>S</span>ea polar bear diets during a period of increasing land use Open
From 2000 to 2013, use of land as a seasonal habitat by polar bears ( Ursus maritimus ) of the southern Beaufort Sea ( SB ) subpopulation substantially increased. This onshore use has been linked to reduced spatial and temporal availabilit…
View article
Choose Your Poison—Space-Use Strategy Influences Pollutant Exposure in Barents Sea Polar Bears Open
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 re…
View article
Evaluating and ranking threats to the long-term persistence of polar bears Open
The polar bear (Ursus maritimus) was listed as a globally threatened species under the U.S. Endangered Species Act (ESA) in 2008, mostly due to the significant threat to their future population viability from rapidly declining Arctic sea i…
View article
High genetic variability of vagrant polar bears illustrates importance of population connectivity in fragmented sea ice habitats Open
Projections by the Intergovernmental Panel on Climate Change (IPCC) and sea ice forecasts suggest that Arctic sea ice will decline markedly in coming decades. Expected effects on the entire ecosystem include a contraction of suitable polar…