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.

Polar Bear tagging in Alaska, 1968

Polar Record ◽  
1969 ◽  
Vol 14 (91) ◽  
pp. 459-462 ◽  
Author(s):  
J. W. Lentfer
Keyword(s):  
Life History ◽  
Air Force ◽  
Research Laboratory ◽  
Polar Bear ◽  
Ursus Maritimus ◽  
The Arctic ◽  
Polar Bears ◽  
The Us ◽  
History Information ◽  
Sport Fisheries

The Alaska Department of Fish and Game started marking Polar Bears (Ursus maritimus) in 1967 to obtain life history information (Lentfer, 1968), and continued in 1968 with the assistance of the US Bureau of Sport Fisheries and Wildlife. Special thanks for use of facilities are given to the Arctic Research Laboratory at Barrow and to the Tin City and Cape Lisburne Air Force stations. Participating biologists were J. W. Lentfer, L. H. Miller, S. H. Eide, and G. N. Bos of the Alaska Department of Fish and Game and J. W. Brooks of the US Bureau of Sport Fisheries and Wildlife.

‘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 The application of life history information to the conservation management of Chrysoritis butterflies (Lepidoptera: Lycaenidae) in South Africa

Koedoe ◽  
2004 ◽  
Vol 47 (1) ◽  
Author(s):  
R.F. Terblanche ◽  
H. Van Hamburg
Keyword(s):  
South Africa ◽  
Life History ◽  
Life Histories ◽  
Host Plants ◽  
Conservation Management ◽  
Aesthetic Value ◽  
Wing Patterns ◽  
In The Wild ◽  
History Of ◽  
Voucher Specimens

Due to their intricate life histories and the unique wing patterns and colouring the butterflies of the genus Chrysoritis are of significant conservation and aesthetic value. Thisoverview probes into practical examples of butterfly life history research applicable to environmental management of this relatively well-known invertebrate group in South Africa. Despite the pioneer work on life histories of Chrysoritis in the past, more should be done to understand the life history of the butterflies in the wild, especially their natural host plants and the behaviour of adults and larvae. A system of voucher specimens of host plants should be introduced in South Africa. Although various host plant species in nature are used by the members of Chrysoritis, including the Chrysoritis chrysaor group, the choice of these in nature by each species is significant for conservation management and in the case of Chrysoritis aureus perhaps even as a specific characteristic.A revision of the ant genus Crematogaster will benefit the conservation management of Chrysoritis species since some of these ant species may consist of a number of specieswith much more restricted distributions than previously thought. Rigorous quantified tudies of population dynamics of Chrysoritis butterflies are absent and the introductionof such studies will benefit conservation management of these localised butterflies extensively.

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.

Protecting California’s Coast

2019 ◽  
pp. 84-114
Author(s):  
David Vogel
Keyword(s):  
Twentieth Century ◽  
San Francisco ◽  
Public Support ◽  
Coastal Areas ◽  
Coastal Protection ◽  
Valuable Resource ◽  
Aesthetic Value ◽  
Economic Resource ◽  
Explanatory Framework ◽  
Business Support

This chapter begins by exploring the conflicts over Southern California's beaches and coastal areas and then turns to efforts to protect the San Francisco Bay and the entire Pacific coast. In addition to its aesthetic value and opportunities for recreation, the coast is a major economic resource. It enhances the value of property located on or near it, and the coastal area also contains substantial deposits of oil. Precisely because the coast is a scarce and valuable resource with so many competing uses, protecting it, like the coastal redwoods, has been highly contentious. On one important dimension, the dynamics of two of the important cases described in this chapter depart from the book's explanatory framework. The campaigns to establish the Bay Conservation and Development Commission, the world's first coastal protection agency, as well as the more sweeping California Coastal Commission, received no business support. In both cases, the interests of business were not divided. Rather, their creation was made possible by extensive citizen mobilization, an outcome that reveals the important role played by public support for environmental protection in California beginning in the middle of the twentieth century.

scholarly journals Box, stalked, and upside-down? Draft genomes from diverse jellyfish (Cnidaria, Acraspeda) lineages: Alatina alata (Cubozoa), Calvadosia cruxmelitensis (Staurozoa), and Cassiopea xamachana (Scyphozoa)

GigaScience ◽  
2019 ◽  
Vol 8 (7) ◽  
Author(s):  
Aki Ohdera ◽  
Cheryl L Ames ◽  
Rebecca B Dikow ◽  
Ehsan Kayal ◽  
Marta Chiodin ◽  
...  
Keyword(s):  
Life History ◽  
Evolutionary History ◽  
Life History Traits ◽  
Hox Genes ◽  
Common Ancestor ◽  
Last Common Ancestor ◽  
Valuable Resource ◽  
Genomic Features ◽  
Cassiopea Xamachana ◽  
Nuisance Species

Abstract Background Anthozoa, Endocnidozoa, and Medusozoa are the 3 major clades of Cnidaria. Medusozoa is further divided into 4 clades, Hydrozoa, Staurozoa, Cubozoa, and Scyphozoa—the latter 3 lineages make up the clade Acraspeda. Acraspeda encompasses extraordinary diversity in terms of life history, numerous nuisance species, taxa with complex eyes rivaling other animals, and some of the most venomous organisms on the planet. Genomes have recently become available within Scyphozoa and Cubozoa, but there are currently no published genomes within Staurozoa and Cubozoa. Findings Here we present 3 new draft genomes of Calvadosia cruxmelitensis (Staurozoa), Alatina alata (Cubozoa), and Cassiopea xamachana (Scyphozoa) for which we provide a preliminary orthology analysis that includes an inventory of their respective venom-related genes. Additionally, we identify synteny between POU and Hox genes that had previously been reported in a hydrozoan, suggesting this linkage is highly conserved, possibly dating back to at least the last common ancestor of Medusozoa, yet likely independent of vertebrate POU-Hox linkages. Conclusions These draft genomes provide a valuable resource for studying the evolutionary history and biology of these extraordinary animals, and for identifying genomic features underlying venom, vision, and life history traits in Acraspeda.

Research and management of polar bears Ursus maritimus

Polar Record ◽  
1986 ◽  
Vol 23 (143) ◽  
pp. 167-176 ◽  
Author(s):  
Ian Stirling
Keyword(s):  
Natural Resources ◽  
Polar Bear ◽  
World Wide ◽  
Ursus Maritimus ◽  
Polar Bears ◽  
International Agreement ◽  
International Union ◽  
International Coordination ◽  
The 1950S ◽  
Circumpolar Arctic

AbstractThrough the 1950s and 1960s there was a marked increase in recorded numbers of polar bears being killed for their hides, giving rise to world-wide concern that the species might be endangered. At a meeting in Fairbanks, Alaska 1965, representatives of circumpolar arctic nations discussed conservation of polar bears and concluded that international coordination of research and management efforts was essential. Subsequent meetings of scientists engaged in polar bear research were organized every two years by the International Union for the Conservation of Nature and Natural Resources, facilitating exchanges of views and cooperation; as a result, in 1973 the International Agreement on the Conservation of Polar Bears and their Habitats was signed in Oslo, Norway. This paper describes some of the research and management undertaken in the years leading up to the agreement, and initiatives that are continuing because of it.

scholarly journals Allee effect in polar bears: a potential consequence of polychlorinated biphenyl contamination

2016 ◽  
Vol 283 (1843) ◽  
pp. 20161883 ◽  
Author(s):  
Viola Pavlova ◽  
Jacob Nabe-Nielsen ◽  
Rune Dietz ◽  
Christian Sonne ◽  
Volker Grimm
Keyword(s):  
Reproductive Success ◽  
Population Growth ◽  
Polar Bear ◽  
Allee Effect ◽  
Polychlorinated Biphenyl ◽  
Sperm Quality ◽  
Male Competition ◽  
Male Reproductive Success ◽  
Male Mating ◽  
Polar Bears

Polar bears ( Ursus maritimus ) from East Greenland and Svalbard exhibited very high concentrations of polychlorinated biphenyls (PCBs) in the 1980s and 1990s. In Svalbard, slow population growth during that period was suspected to be linked to PCB contamination. In this case study, we explored how PCBs could have impacted polar bear population growth and/or male reproductive success in Svalbard during the mid-1990s by reducing the fertility of contaminated males. A dose–response relationship linking the effects of PCBs to male polar bear fertility was extrapolated from studies of the effects of PCBs on sperm quality in rodents. Based on this relationship, an individual-based model of bear interactions during the breeding season predicted fertilization success under alternative assumptions regarding male–male competition for females. Contamination reduced pregnancy rates by decreasing the availability of fertile males, thus triggering a mate-finding Allee effect, particularly when male–male competition for females was limited or when infertile males were able to compete with fertile males for females. Comparisons of our model predictions on age-dependent reproductive success of males with published empirical observations revealed that the low representation of 10–14-year-old males among breeding males documented in Svalbard in mid-1990s could have resulted from PCB contamination. We conclude that contamination-related male infertility may lead to a reduction in population growth via an Allee effect. The magnitude of the effect is largely dependent on the population-specific mating system. In eco-toxicological risk assessments, appropriate consideration should therefore be given to negative effects of contaminants on male fertility and male mating behaviour.

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