scholarly journals On the integration of ecological and physiological variables in polar bear toxicology research: a systematic review

2018 ◽  
Vol 26 (1) ◽  
pp. 1-12 ◽  
Author(s):  
Thea Bechshoft ◽  
Andrew E. Derocher ◽  
Michelle Viengkone ◽  
Heli Routti ◽  
Jon Aars ◽  
...  
Keyword(s):  
Polar Bear ◽  
Barents Sea ◽  
Temporal Trends ◽  
Polar Bears ◽  
Unintended Effects ◽  
Apex Predators ◽  
Pollution Effects ◽  
Contaminant Exposure ◽  
Physiological Variables ◽  
Ecological Variables

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, present-day polar bear toxicological papers often incorporate ecological variables. This systematic literature review investigates the ecological and physiological variables that have been integrated in such studies. The systematic literature search resulted in 207 papers, published between 1970 and 2016. Representation of each of the 19 polar bear subpopulations varied from 0 to 72 papers; East Greenland, Barents Sea, Southern Beaufort Sea, and Lancaster Sound had the most published research, with over 30 papers each. Samples were collected between 1881 and 2015, primarily from harvested bears (66%); most from the 1990s and 2000s. Adipose tissue, liver, and blood were the most common tissues examined, and mean number of bears analyzed per paper was 76 (range 1–691). Papers investigating temporal trends did so using a mean sample of 61 bears over a 6-year period.The frequency with which ecological and physiological variables were integrated into toxicological papers varied. Age and (or) sex was the only ecological variable(s) considered in 51% of papers. Further, a total of 37% of the papers included in the review investigated physiological effects in relation to contaminant concentrations. Of the papers, 98% dealt with contaminant exposure at the individual level, leaving population level effects largely unstudied. Solitary subadult and adult polar bears were included in 57% and 79% of the papers, respectively. Younger bears were included in fewer papers: yearlings in 20% and cubs-of-the-year in 13%. Only 12% of the papers examined reproduction relative to contaminants. Finally, body condition was included in 26% of the research papers, whereas variables related to polar bear diet were included in ≤9%. Based on our findings, we suggest future polar bear toxicology studies increase sample sizes, include more ecological variables, increase studies on family groups, and increase the applicability of studies to management and conservation by examining pollution effects on reproduction and survival.

scholarly journals Predation of Harp Seals, Pagophilus groenlandicus, by Polar Bears, Ursus maritimus, in Svalbard

ARCTIC ◽  
2019 ◽  
Vol 72 (2) ◽  
pp. 197-202 ◽  
Author(s):  
Thomas G. Smith ◽  
Ian Stirling
Keyword(s):  
Sea Ice ◽  
Polar Bear ◽  
Barents Sea ◽  
Population Level ◽  
Open Water ◽  
Ursus Maritimus ◽  
Polar Bears ◽  
Pagophilus Groenlandicus ◽  
Large Numbers ◽  
Pack Ice

Harp seals (Pagophilus groenlandicus) that breed in February and March in the White Sea migrate to open water around Svalbard and Franz Josef Land in the Barents Sea, feeding pelagically while following the receding ice edge northward to the edge of the polar pack. Although harp seals are present throughout the area during the summer, they are primarily pelagic and do not appear to be extensively preyed upon by polar bears (Ursus maritimus). However, occasionally, large numbers of harp seals may haul out and rest on the pack ice or feed in the water below the ice and surface to breathe between the floes. When approached by a polar bear while on the ice, harp seals do not exhibit the instant flight response characteristic of the polar bear’s primary prey species, ringed (Pusa hispida) and bearded seals (Erignathus barbatus). In this situation, polar bears may make multiple kills without either consuming their own prey or scavenging seals killed by other bears. This behavior appears not to frighten other nearby harp seals, whether hauled out on the ice or in the water below the floes. These unusual concentrations of harp seals hauled out on sea ice may be related to the distribution and abundance of fish or other epontic prey. Their lack of an escape response to predators on the surface of the sea ice is probably a result of briefly hauling out in large numbers in spring while whelping on the sea ice in areas where the consequences of potential polar bear predation are insignificant. The rare events of harp seal mortality from bears killing them on the surface of pack ice during the summer do not appear to have a significant impact at the population level of either species.

Aerial strip surveys of polar bears in the Barents Sea

1990 ◽  
Vol 8 (2) ◽  
pp. 309-311
Author(s):  
Øystein Wiig ◽  
Vidar Bakken
Keyword(s):  
Barents Sea ◽  
Polar Bears ◽  
The Barents Sea

Space-Use Strategy Is an Important Determinant of PCB Concentrations in Female Polar Bears in the Barents Sea

2003 ◽  
Vol 37 (21) ◽  
pp. 4919-4924 ◽  
Author(s):  
Gro H. Olsen ◽  
Mette Mauritzen ◽  
Andrew E. Derocher ◽  
Eugen G. Sørmo ◽  
Janneche U. Skaare ◽  
...  
Keyword(s):  
Barents Sea ◽  
Important Determinant ◽  
Space Use ◽  
Polar Bears ◽  
The Barents Sea

scholarly journals The Life and Status of the Polar Bear

Oryx ◽  
1965 ◽  
Vol 8 (3) ◽  
pp. 169-176 ◽  
Author(s):  
C. R. Harrington
Keyword(s):  
Life History ◽  
Endangered Species ◽  
Polar Bear ◽  
Polar Bears ◽  
Valuable Resource ◽  
Kind Permission ◽  
Complete Protection ◽  
Aesthetic Value ◽  
Arctic Species ◽  
Canadian Wildlife

Polar bears are on the IUCN list of endangered species. In 1961, when there were signs of serious depletions, the Canadian Wildlife Service started a five-year research project on the polar bear's biology and ecology, and the author is engaged on this work. He points out that polar bears are a most valuable resource, especially to the Canadian Eskimos, and if their numbers are allowed to dwindle to the point at which they have to be given complete protection they will have little more than aesthetic value, which in the case of an Arctic species is limited. These extracts from a comprehensive paper on the polar bear's life history and status are reproduced from “Canadian Audubon” by kind permission of the author and editor.

‘Verscheurende Beyren’

2022 ◽  
Vol 71 (1) ◽  
pp. 92-115
Author(s):  
Robert Bauernfeind
Keyword(s):  
Polar Bear ◽  
The Arctic ◽  
Polar Bears

This article examines the depiction of polar bears in Dutch painting and graphics from the late 16th to the early 18th centuries. Reports of the first encounters between Dutch humans and polar bears established the idea of these animals as aggressive predators. This idea dominated the image of the bear in illustrated travelogues as well as in allegorical depictions of the Arctic and whaling pictures. The polar bear thus became a symbol for the dangers of the region and appears as an obstacle to the human exploitation of the Arctic. However, depictions of the bloody hunt for polar bears indicate the economically motivated triumph of Europeans in this inhospitable area.

scholarly journals An analysis of heat conduction in polar bear hairs using one-dimensional fractional model

2016 ◽  
Vol 20 (3) ◽  
pp. 785-788 ◽  
Author(s):  
Wei-Hong Zhu ◽  
Shao-Tang Zhang ◽  
Zheng-Biao Li
Keyword(s):  
Heat Conduction ◽  
Heat Conduction Equation ◽  
Polar Bear ◽  
Thermal Protection ◽  
Polar Bears ◽  
Cold Environment ◽  
Membrane Pore ◽  
One Dimensional ◽  
Fractional Heat Conduction ◽  
Maintain Body Temperature

Hairs of a polar bear are of superior properties such as the excellent thermal protection. The polar bears can perennially live in an extremely cold environment and can maintain body temperature at around 37 ?C. Why do polar bears can resist such cold environment? Its membrane-pore structure plays an important role. In the previous work, we established a 1-D fractional heat conduction equation to reveal the hidden mechanism for the hairs. In this paper, we further discuss solutions and parameters of the equation established and analyze heat conduction in polar bear hairs.

scholarly journals Conservation status of polar bears ( Ursus maritimus ) in relation to projected sea-ice declines

2016 ◽  
Vol 12 (12) ◽  
pp. 20160556 ◽  
Author(s):  
Eric V. Regehr ◽  
Kristin L. Laidre ◽  
H. Resit Akçakaya ◽  
Steven C. Amstrup ◽  
Todd C. Atwood ◽  
...  
Keyword(s):  
Sea Ice ◽  
Polar Bear ◽  
Extinction Risk ◽  
Conservation Status ◽  
Iucn Red List ◽  
Arctic Sea Ice ◽  
Polar Bears ◽  
Near Term ◽  
Conservation Assessments ◽  
Global Population

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, which determines the timeframe for conservation assessments; (ii) developing a standardized sea-ice metric representing important habitat; and (iii) using statistical models and computer simulation to project changes in the global population under three approaches relating polar bear abundance to sea ice. Mean GL was 11.5 years. Ice-covered days declined in all subpopulation areas during 1979–2014 (median −1.26 days year −1 ). The estimated probabilities that reductions in the mean global population size of polar bears will be greater than 30%, 50% and 80% over three generations (35–41 years) were 0.71 (range 0.20–0.95), 0.07 (range 0–0.35) and less than 0.01 (range 0–0.02), respectively. According to IUCN Red List reduction thresholds, which provide a common measure of extinction risk across taxa, these results are consistent with listing the species as vulnerable. Our findings support the potential for large declines in polar bear numbers owing to sea-ice loss, and highlight near-term uncertainty in statistical projections as well as the sensitivity of projections to different plausible assumptions.

Polar bear research: has science helped management and conservation?

2018 ◽  
Vol 26 (4) ◽  
pp. 358-368 ◽  
Author(s):  
Dag Vongraven ◽  
Andrew E. Derocher ◽  
Alyssa M. Bohart
Keyword(s):  
Temporal Trends ◽  
Scientific Data ◽  
Annual Number ◽  
Polar Bears ◽  
International Agreement ◽  
Research Relationship ◽  
Spatial Coverage ◽  
Scientific Papers ◽  
Sound Management ◽  
Management And Conservation

Wildlife management is predicated upon the use of scientific research to assist decision-making. However, assessment of the effectiveness of the management–research relationship is rarely undertaken. Polar bears (Ursus maritimus) have benefitted from an international agreement that required each of the countries within the species’ range to manage them using the best available scientific data. The objective of this paper is to conduct a systematic review of peer-reviewed literature on polar bears to describe research trends and to assess how effectively research has met management needs. We analyzed 1191 peer-reviewed scientific papers from 1886–2016 covering 24 research topics. Annual counts of papers within each research topic were assessed for temporal trends, spatial coverage, and the extent to which they have facilitated management and monitoring needs. The annual number of papers increased from <10 in the early 1960s to >50 in recent years with a mean of 2.2 papers per subpopulation per year with great variation between the 19 global subpopulations. We conclude that there is an imbalance in the geographic and thematic focus of peer-reviewed research in recent years, and that only four subpopulations appear to have had a research focus covering most parameters essential for conservation and sound management.

scholarly journals Estimation and classification of temporal trends to support integrated ecosystem assessment

2020 ◽  
Author(s):  
Hiroko Kato Solvang ◽  
Benjamin Planque
Keyword(s):  
Time Series ◽  
Barents Sea ◽  
Multivariate Time Series ◽  
Marine Ecosystem ◽  
Temporal Trends ◽  
Dynamic Factor ◽  
Short Time Series ◽  
Common Trends ◽  
Common Trend ◽  
Short Time

Abstract We propose a trend estimation and classification (TREC) approach to estimating dominant common trends among multivariate time series observations. Our methods are based on two statistical procedures that includes trend modelling and discriminant analysis for classifying similar trend (common trend) classes. We use simulations to evaluate the proposed approach and compare it with a relevant dynamic factor analysis in the time domain, which was recently proposed to estimate common trends in fisheries time series. We apply the TREC approach to the multivariate short time series datasets investigated by the ICES integrated assessment working groups for the Norwegian Sea and the Barents Sea. The proposed approach is robust for application to short time series, and it directly identifies and classifies the dominant trends underlying observations. Based on the classified trend classes, we suggest that communication among stakeholders like marine managers, industry representatives, non-governmental organizations, and governmental agencies can be enhanced by finding the common tendency between a biological community in a marine ecosystem and the environmental factors, as well as by the icons produced by generalizing common trend patterns.

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