Jon Aars

Jon Aars
Norwegian Polar Institute · Scientific Research Department

PhD

About

171
Publications
61,474
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Introduction
Skills and Expertise
Additional affiliations
January 2003 - present
Norwegian Polar Institute
Position
  • Researcher

Publications

Publications (171)
Article
Polar bears are susceptible to climate warming because of their dependence on sea ice, which is declining rapidly. We present the first evidence for a genetically distinct and functionally isolated group of polar bears in Southeast Greenland. These bears occupy sea-ice conditions resembling those projected for the High Arctic in the late 21st centu...
Article
Full-text available
Aim Identify hotspots and areas of high species richness for Arctic marine mammals. Location Circumpolar Arctic. Methods A total of 2115 biologging devices were deployed on marine mammals from 13 species in the Arctic from 2005 to 2019. Getis‐Ord Gi* hotspots were calculated based on the number of individuals in grid cells for each species and fo...
Article
Full-text available
Satellite telemetry (ST) has played a critical role in the management and conservation of polar bears (Ursus maritimus) over the last 50 years. ST data provide biological information relevant to subpopulation delineation, movements, habitat use, maternal denning, health, human-bear interactions, and accurate estimates of vital rates and abundance....
Article
Full-text available
Climate warming has resulted in extensive sea ice loss across the Arctic. Polar bears (Ursus maritimus) rely on sea ice for hunting, resting, travelling and in some parts of the Arctic also maternity denning. In the European Arctic, polar bears rely on snow drifts on land to den and give birth. Consequently, timely arrival of sea ice around land ma...
Article
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The Arctic is warming rapidly, with concomitant sea ice losses and ecosystem changes. The animals most vulnerable to Arctic food web changes are long-lived and slow-growing such as marine mammals, which may not be able to adapt rapidly enough to respond to changes in their resource bases. To determine the current extent and sources of these resourc...
Article
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There has been a considerable number of reports on Hg concentrations in Arctic mammals since the last Arctic Monitoring and Assessment Programme (AMAP) effort to review biological effects of the exposure to mercury (Hg) in Arctic biota in 2010 and 2018. Here, we provide an update on the state of the knowledge of health risk associated with Hg conce...
Article
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We examined spatial variation in total mercury (THg) concentrations in 100 hair samples collected between 2008 and 2016 from 87 polar bears (Ursus maritimus) from the Norwegian (Svalbard Archipelago, western Barents Sea) and Russian Arctic (Kara Sea, Laptev Sea, and Chukchi Sea). We used latitude and longitude of home range centroid for the Norwegi...
Article
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The polar bear Ursus maritimus is one of the species most endangered by the rapidly declining sea–ice cover in the Arctic, which they use as a platform to hunt fatty, high-energy seals. In recent decades, more polar bears have been forced to remain longer on land, so their access to seals is limited. The importance of terrestrial food to polar bear...
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Loss of Arctic sea ice owing to climate change is predicted to reduce both genetic diversity and gene flow in ice-dependent species, with potentially negative consequences for their long-term viability. Here, we tested for the population-genetic impacts of reduced sea ice cover on the polar bear (Ursus maritimus) sampled across two decades (1995-20...
Chapter
Although the Arctic has experienced previous periods of warmer climate, the rate of sea ice loss in recent decades is likely faster than polar bears have ever experienced. The rapidly changing climate means that any response in polar bear behavior is unlikely to be driven by microevolution, but rather it will depend on behavioral plasticity. Fortun...
Article
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This study investigated concentrations of phthalates (diesters of phthalic acids) in blubber/adipose tissue of blue whales (Balaenoptera musculus), fin whales (Balaenoptera physalus), bowhead whales (Balaena mysticetus) and polar bears (Ursus maritimus) sampled in the Svalbard Archipelago (extending westward in the case of bowhead whales). Addition...
Article
Philopatry influences animal distribution and can lead to a kinship-based spatial structure, where proximity and relatedness are tightly linked. In the Barents Sea region, polar bears (Ursus maritimus) of the coastal ecotype remain year-round within the Svalbard archipelago. This coastal strategy is thought to be stable across years; however, littl...
Article
Full-text available
• In species providing extended parental care, one or both parents care for altricial young over a period including more than one breeding season. We expect large parental investment and long‐term dependency within family units to cause high variability in life trajectories among individuals with complex consequences at the population level. So far...
Article
Being at the food chain apex, polar bears (Ursus maritimus) are highly contaminated with persistent organic pollutants (POPs). Females transfer POPs to their offspring through gestation and lactation, therefore, young cubs present higher POPs concentrations than their mothers. Recent studies suggest that POPs affect lipid metabolism in female polar...
Article
Temporal trends of total mercury (THg) were examined in female polar bear (Ursus maritimus) hair (n = 199) from the Barents Sea in 1995-2016. In addition, hair values of stable isotopes (n = 190-197) of carbon (δ13C), sulfur (δ34S), and nitrogen (δ15N), and information on breeding status, body condition (BCI) and age was obtained. Stable isotope va...
Article
Full-text available
Polar bears Ursus maritimus are currently facing rapid environmental changes with loss of sea ice and shifts in their prey distribution. Two distinct ecotypes exist in the Barents Sea, where sea ice is decreasing at the highest rate in the Arctic. Coastal bears remain within the Archipelago of Svalbard year-round, whereas offshore bears follow the...
Article
Full-text available
We evaluated a novel tool that predicts possible maternity den habitat of the polar bear (Ursus maritimus) based on a physical snow transport model, a digital terrain model and weather data. We observed and compared den locations in three important denning areas in east Svalbard (Kongsøya, n = 288; Svenskøya, n = 86; Hopen, n = 115) with modelled s...
Article
In the Barents Sea, pelagic and coastal polar bears are facing various ecological challenges that may explain the difference in their pollutant levels. We measured polychlorinated biphenyls, organochlorine pesticides, polybrominated diphenyl ethers in fat, and perfluoroalkyl substances in plasma in pelagic and coastal adult female polar bears with...
Article
Full-text available
Since the last Arctic Monitoring and Assessment Programme (AMAP) effort to review biological effects of the exposure to organohalogen compounds (OHCs) in Arctic biota, there has been a considerable number of new Arctic effect studies. Here, we provide an update on the state of the knowledge of OHC, and also include mercury, exposure and/or associat...
Article
Full-text available
Life-history theory predicts that females' age and size affect the level of maternal investment in current reproduction, balanced against the future reproductive effort, maintenance and survival. Using long-term (30 years) individual data on 193 female polar bears ( Ursus maritimus), we assessed age- and size-specific variation on litter size. Litt...
Preprint
Full-text available
In species providing extended parental care, one or both parents care for altricial young over a period including more than one breeding season. We expect large parental investment and long-term dependency within family units to cause high variability in life trajectories among individuals with complex consequences at the population level. So far,...
Article
Ringed seals are a central component of the Arctic ecosystem; they have a circumpolar distribution and are both important predators of lower trophic animals (invertebrates and fishes) and prey for polar bears and coastal human populations. They depend on sea ice for reproduction, moulting and resting, and they consume significant amounts of ice-ass...
Article
Full-text available
Knowledge of subpopulation identity including substructure is a prerequisite for sound management of polar bears (Ursus maritimus). It is not known whether the present catch of polar bears in the East Greenland subpopulation (EG) is sustainable. We used the Mean Measure of Divergence (MMD) to examine geographical variation in non-metrical traits fr...
Article
Temporal trends of persistent organic pollutants (POPs: PCBs, OH-PCBs, p,p’-DDE, HCB, β-HCH, oxychlordane, BDE-47 and 153) in relation to changes in feeding habits and body condition in adult female polar bears (Ursus maritimus) from the Barents Sea subpopulation were examined over 20 years (1997-2017). All 306 samples were collected in the spring...
Article
Full-text available
Temporal trends of persistent organic pollutants (POPs: PCBs, OH-PCBs, p,p′-DDE, HCB, β-HCH, oxy-chlordane, BDE-47, and 153) in relation to changes in feeding habits and body condition in adult female polar bears (Ursus maritimus) from the Barents Sea subpopulation were examined over 20 years (1997−2017). All 306 samples were collected in the sprin...
Preprint
Full-text available
Life history theory predicts that females' age and size affect the level of maternal investment in current reproduction, balanced against future reproductive effort, maintenance and survival. Using long-term (30 years) individual data on 231 female polar bears (Ursus maritimus), we assessed age- and size-specific variation on litter size. Litter si...
Article
Full-text available
Polar bears are ice-associated marine mammals that are known to swim and dive, yet their aquatic behaviour is poorly documented. Reductions in Arctic sea ice are clearly a major threat to this species, but understanding polar bears' potential behavioural plasticity with respect to the ongoing changes requires knowledge of their swimming and diving...
Technical Report
Full-text available
I Tildelingsbrev 2016 fra Klima- og miljødepartementet (KLD) fikk Norsk Polarinstitutt følgende oppdrag med frist 1. april 2017: «Etter bestilling fra Sysselmannen levere kunnskapsgrunnlag for forvaltningsplaner for nasjonalparkene på Sentral-Spitsbergen (Nordre Isfjorden, Sassen-Bünsow Land, Indre Wijdefjorden og Nordenskiöld Land), samt Festning...
Article
In the present study, blood clinical-chemical parameters (BCCPs) were analysed in 20 female and 18 male Svalbard polar bears (Ursus maritimus) captured in spring 2007. The aim was to study how age, body condition (BC), biometrics, plasma lipid content and geographical location may confound the relationship between persistent organic pollutants (POP...
Article
Full-text available
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 relation to space-use patterns (offshore vs coastal) in adult female polar bears from the Barents Sea equipped wit...
Article
Full-text available
There is growing evidence from experimental and human epidemiological studies that many pollutants can disrupt lipid metabolism. In Arctic wildlife, the occurrence of such compounds could have serious consequences for seasonal feeders. We set out to study whether organohalogenated compounds (OHCs) could cause disruption of energy metabolism in fema...
Article
As apex predators, polar bears (Ursus maritimus) are among the most heavily polluted organisms in the Arctic. In addition to this anthropogenic stressor, climate warming has been shown to negatively affect their body condition, reproductive output and survival. Among potential underlying physiological mechanisms, thyroid hormones (THs), which contr...
Article
Full-text available
We monitored concentrations of per- and polyfluoroalkyl substances (PFASs) in relation to climate-associated changes in feeding habits and food availability in polar bears (Ursus maritimus) and arctic foxes (Vulpes lagopus) (192 plasma and 113 liver samples, respectively) sampled from Svalbard, Norway, during 1997-2014. PFASs concentrations became...
Article
The aim of this study was to determine the effects of persistent organic pollutants (POPs) and biometric variables on circulating levels of steroid hormones (androgens, estrogens and progestagens) in male polar bears (Ursus maritimus) from Svalbard, Norway (n = 23). Levels of pregnenolone (PRE), progesterone (PRO), androstenedione (AN), dehydroepia...
Article
Full-text available
Ecotoxicology evolved as a scientific field as awareness of the unintended effects of anthropogenic pollutants in biota increased. Polar bears (Ursus maritimus) are often the focus of Arctic contaminant exposure studies because they are apex predators with high contaminant loads. While early studies focused on describing and quantifying pollutants,...
Article
The Arctic is warming more rapidly than other region on the planet, and the northern Barents Sea, including the Svalbard Archipelago, is experiencing the fastest temperature increases within the circumpolar Arctic, along with the highest rate of sea ice loss. These physical changes are affecting a broad array of resident Arctic organisms as well as...
Article
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 capacity and inform management efforts designed to mitigate against negative impacts. 2.We investigated how the movement a...
Article
Global climate changes are magnified in the Arctic and are having an especially dramatic effect on the spatial and temporal distribution and the thickness traits of sea ice. Decline of Arctic sea ice may lead to qualitative and/or quantitative changes in diet and reduced body condition (i.e. adipose tissue stores) of ice-associated apex predators s...
Article
Full-text available
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 bear numbers and reveal population substructure. DNA profiles from biopsy samples and ear tags identified on p...
Article
Full-text available
We quantified the effect of multiple environmental and biological determinants on variation in home range size across multiple spatial (total-home range–core-home range areas) and temporal (seasonal and all seasons combined) scales for 22 adult female polar bears (Ursus maritimus) from Svalbard, Norway (2003–2011). We also evaluated if considering...
Article
Full-text available
This paper examines how anthropogenic threats, such as disturbance, pollution and climate change, are linked to polar bear (Ursus maritimus) population biology in the Svalbard and Barents Sea area, with the aim to increase our understanding of how human activity may impact the population. Overharvesting drastically reduced the population of polar b...
Article
Full-text available
Global changes are thought to affect most Arctic species, yet some populations are more at risk. Today, the Barents Sea ecoregion is suffering the strongest sea ice retreat ever measured; and these changes are suspected to modify food access and thus diet of several species. Biochemical diet tracers enable investigation of diet in species such as p...
Data
Fatty acid and stable isotope determination. (DOCX)
Data
Number of samples available for stable isotopes in plasma and red blood cells (n = 112) and fatty acids in adipose tissue (n = 83) of female polar bears from Svalbard (2012–2013). Samples are then sorted by year, sampling location, breeding status and season. (DOCX)
Data
Average (± standard deviation, SD) mass % of fatty acids in polar bear adipose tissue. Samples were collected from 83 females in Svalbard archipelago in 2012 and 2013. FA in bold are those selected for statistical analyses. (DOCX)
Data
List of the 15 candidate models used for model selection. We used model selection via AICc to determine the best predictors of nitrogen and carbon stable isotope values in plasma and red blood cells, and fatty acid composition in adipose tissue (using principal components values). (DOCX)
Article
Full-text available
The population size of Atlantic walruses (Odobenus rosmarus rosmarus) is depleted relative to historical abundance levels. In Svalbard, centuries of over-exploitation brought the walrus herds to the verge of extinction, and such bottlenecks may have caused loss of genetic variation. To address this for Svalbard walruses, mitochondrial haplotypes of...