scholarly journals Wolf (Canis lupus) Predation of a Polar Bear (Ursus maritimus) Cub on the Sea Ice off Northwestern Banks Island, Northwest Territories, Canada

ARCTIC ◽  
2009 ◽  
Vol 59 (3) ◽  
Author(s):  
E.S. Richardson ◽  
D. Andriashek
Keyword(s):  
Sea Ice ◽  
Northwest Territories ◽  
Canis Lupus ◽  
Polar Bear ◽  
Ursus Maritimus ◽  
Banks Island

scholarly journals Testing the hypothesis that routine sea ice coverage of 3-5 mkm2 results in a greater than 30% decline in population size of polar bears (Ursus maritimus)

2017 ◽  
Author(s):  
Susan J Crockford
Keyword(s):  
Sea Ice ◽  
Population Size ◽  
Habitat Loss ◽  
Polar Bear ◽  
Population Decline ◽  
Ursus Maritimus ◽  
The Arctic ◽  
Polar Bears ◽  
Population Declines ◽  
Sea Ice Decline

The polar bear (Ursus maritimus) was the first species to be classified as threatened with extinction based on predictions of future conditions rather than current status. These predictions were made using expert-opinion forecasts of population declines linked to modeled habitat loss – first by the International Union for the Conservation of Nature (IUCN)’s Red List in 2006, and then by the United States Fish and Wildlife Service (USFWS) in 2008 under the Endangered Species Act (ESA), based on data collected to 2005 and 2006, respectively. Both assessments predicted significant population declines of polar bears would result by mid-century as a consequence of summer sea ice extent rapidly reaching 3-5 mkm2 on a regular basis: the IUCN predicted a >30% decline in total population, while the USFWS predicted the global population would decline by 67% (including total extirpation of ten subpopulations within two vulnerable ecoregions). Biologists involved in these conservation assessments had to make several critical assumptions about how polar bears might be affected by future habitat loss, since sea ice conditions predicted to occur by 2050 had not occurred prior to 2006. However, summer sea ice declines have been much faster than expected: low ice levels not expected until mid-century (about 3-5 mkm2) have occurred regularly since 2007. Realization of predicted sea ice levels allows the ‘rapid sea ice decline = population decline’ assumption for polar bears to be treated as a testable hypothesis. Data collected between 2007 and 2015 reveal that polar bear numbers have not declined as predicted and no subpopulation has been extirpated. Several subpopulations expected to be at high risk of decline remained stable and five showed increases in population size. Another at-risk subpopulation was not counted but showed marked improvement in reproductive parameters and body condition with less summer ice. As a consequence, the hypothesis that repeated summer sea ice levels of below 5 mkm2 will cause significant population declines in polar bears is rejected, a result that indicates the ESA and IUCN judgments to list polar bears as threatened based on future risks of habitat loss were scientifically unfounded and that similar predictions for Arctic seals and walrus may be likewise flawed. The lack of a demonstrable ‘rapid sea ice decline = population decline’ relationship for polar bears also potentially invalidates updated survival model outputs that predict catastrophic population declines should the Arctic become ice-free in summer.

scholarly journals Testing the hypothesis that routine sea ice coverage of 3-5 mkm2 results in a greater than 30% decline in population size of polar bears (Ursus maritimus)

2017 ◽  
Author(s):  
Susan J Crockford
Keyword(s):  
Sea Ice ◽  
Population Size ◽  
Habitat Loss ◽  
Polar Bear ◽  
Population Decline ◽  
Ursus Maritimus ◽  
The Arctic ◽  
Polar Bears ◽  
Population Declines ◽  
Sea Ice Decline

The polar bear (Ursus maritimus) was the first species to be classified as threatened with extinction based on predictions of future conditions rather than current status. These predictions were made using expert-opinion forecasts of population declines linked to modeled habitat loss – first by the International Union for the Conservation of Nature (IUCN)’s Red List in 2006, and then by the United States Fish and Wildlife Service (USFWS) in 2008 under the Endangered Species Act (ESA), based on data collected to 2005 and 2006, respectively. Both assessments predicted significant population declines of polar bears would result by mid-century as a consequence of summer sea ice extent rapidly reaching 3-5 mkm2 on a regular basis: the IUCN predicted a >30% decline in total population, while the USFWS predicted the global population would decline by 67% (including total extirpation of ten subpopulations within two vulnerable ecoregions). Biologists involved in these conservation assessments had to make several critical assumptions about how polar bears might be affected by future habitat loss, since sea ice conditions predicted to occur by 2050 had not occurred prior to 2006. However, summer sea ice declines have been much faster than expected: low ice levels not expected until mid-century (about 3-5 mkm2) have occurred regularly since 2007. Realization of predicted sea ice levels allows the ‘rapid sea ice decline = population decline’ assumption for polar bears to be treated as a testable hypothesis. Data collected between 2007 and 2015 reveal that polar bear numbers have not declined as predicted and no subpopulation has been extirpated. Several subpopulations expected to be at high risk of decline remained stable and five showed increases in population size. Another at-risk subpopulation was not counted but showed marked improvement in reproductive parameters and body condition with less summer ice. As a consequence, the hypothesis that repeated summer sea ice levels of below 5 mkm2 will cause significant population declines in polar bears is rejected, a result that indicates the ESA and IUCN judgments to list polar bears as threatened based on future risks of habitat loss were scientifically unfounded and that similar predictions for Arctic seals and walrus may be likewise flawed. The lack of a demonstrable ‘rapid sea ice decline = population decline’ relationship for polar bears also potentially invalidates updated survival model outputs that predict catastrophic population declines should the Arctic become ice-free in summer.

Movement of a female polar bear (Ursus maritimus) in the Kara Sea during the summer sea-ice break-up

2017 ◽  
Vol 472 (1) ◽  
pp. 17-20 ◽  
Author(s):  
V. V. Rozhnov ◽  
N. G. Platonov ◽  
S. V. Naidenko ◽  
I. N. Mordvintsev ◽  
E. A. Ivanov
Keyword(s):  
Sea Ice ◽  
Polar Bear ◽  
Ursus Maritimus ◽  
Kara Sea ◽  
Female Polar Bear ◽  
Break Up

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.

scholarly journals High contributions of sea ice derived carbon in polar bear (Ursus maritimus) tissue

PLoS ONE ◽  
2018 ◽  
Vol 13 (1) ◽  
pp. e0191631 ◽  
Author(s):  
Thomas A. Brown ◽  
Melissa P. Galicia ◽  
Gregory W. Thiemann ◽  
Simon T. Belt ◽  
David J. Yurkowski ◽  
...  
Keyword(s):  
Sea Ice ◽  
Polar Bear ◽  
Ursus Maritimus

Space use by polar bears in and around Auyuittuq National Park, Northwest Territories, during the ice-free period

1997 ◽  
Vol 75 (10) ◽  
pp. 1585-1594 ◽  
Author(s):  
Steven H. Ferguson ◽  
François Messier ◽  
Mitchell K. Taylor
Keyword(s):  
Sea Ice ◽  
Northwest Territories ◽  
National Park ◽  
Polar Bear ◽  
Satellite Telemetry ◽  
Space Use ◽  
Polar Bears ◽  
Site Specific ◽  
Pregnant Females ◽  
High Elevations

We investigated patterns of space use by polar bears (Ursus maritimus) in and around Auyuittuq National Park, Northwest Territories, during the ice-free period in 1991–1995, using satellite telemetry and capture locations. Female polar bears showed general fidelity to the region but no site-specific fidelity. The pattern of sea-ice ablation influenced when and where bears were forced to leave the ice for land, usually at the end of August. While awaiting the return of sea ice, bears conserved energy by reducing movement and activity. Bears left the land after ice formed that was strong enough to support them, usually in mid-November. During the ice-free period, females with cubs of the year were farther inland, closer to fjords, and less likely to use islands than were males. Males found close to females with cubs of the year were thinner than the average male, suggesting that segregation may result from the threat of intraspecific predation. Females with cubs of the year left the ice for land earlier than other classes of bears and rarely used snow shelters. After about 1 week on land, pregnant females entered a maternal den for the winter. Unlike those in other polar bear populations, most females with 1-year-olds entered a shelter after about 3 weeks on land and remained there for about 2 months. Dens and shelters were located at high elevations and far from the coast, and sheltering bears weighed more than nonsheltering bears.

Conservation and management of Canada’s polar bears (Ursus maritimus) in a changing Arctic1This review is part of the virtual symposium “Flagship Species – Flagship Problems” that deals with ecology, biodiversity and management issues, and climate impacts on species at risk and of Canadian importance, including the polar bear (Ursus maritimus), Atlantic cod (Gadus morhua), Piping Plover (Charadrius melodus), and caribou (Rangifer tarandus).

2011 ◽  
Vol 89 (5) ◽  
pp. 371-385 ◽  
Author(s):  
E. Peacock ◽  
A.E. Derocher ◽  
G.W. Thiemann ◽  
I. Stirling
Keyword(s):  
Climate Change ◽  
Sea Ice ◽  
Polar Bear ◽  
Atlantic Cod ◽  
Ursus Maritimus ◽  
Climate Impacts ◽  
Polar Bears ◽  
Charadrius Melodus ◽  
Land Claims ◽  
Conservation And Management

Canada has an important responsibility for the research, conservation, and management of polar bears ( Ursus maritimus Phipps, 1774) because the majority of polar bears in the world occur within the nation’s borders. Two fundamental and recent changes for polar bears and their conservation have arisen: (1) the ongoing and projected further decline of sea-ice habitat as a result of climate change and (2) the implementation of aboriginal land claims and treaties in Canada’s North. Science has documented empirical links between productivity of polar bear population and sea-ice change. Predictive modeling based on these data has forecast significant declines in polar bear abundance and distribution of polar bears. With the signing of northern land claims and treaties, polar bear management in Canada has integrated local aboriginal participation, values, and knowledge. The interaction of scientific and local perspectives on polar bears as they relate to harvest, climate change, and declining habitat has recently caused controversy. Some conservation, management, and research decisions have been contentious because of gaps in scientific knowledge and the polarization and politicization of the roles of the various stakeholders. With these ecological and governance transitions, there is a need to re-focus and re-direct polar bear conservation in Canada.

scholarly journals Use by polar bear (ursus maritimus) of the habitat along coastline throughout the year according to satellite monitoring data

2019 ◽  
pp. 80-91
Author(s):  
N. G. Platonov ◽  
I. A. Mizin ◽  
E. A. Ivanov ◽  
I. N. Mordvintsev ◽  
S. V. Naydenko ◽  
...  
Keyword(s):  
Sea Ice ◽  
Resource Use ◽  
Polar Bear ◽  
Ursus Maritimus ◽  
Water Area ◽  
Monitoring Data ◽  
Satellite Monitoring ◽  
Monthly Scale

A polar bear female (Ursus maritimus) was captured and marked by satellite collar of the Argos system on Vaygach Island. Data of location relative to the coastline in the Kara Gate from April 2016 to September 2017 was analyzed. An analysis of the polar bear trajectory revealed periods of its greater (when on ice) and less (on land) mobility and directed of movement. The largest area of the polar bear habitat on an average monthly scale was in May 2016, when moving on small-hit ice, the smallest – in January 2017, when on land with no ice. We estimated the distance to the coast to analysis for resource use (27% of the time on the coast, 33% on land, 40% in the water area). Comparison with our previous studies has shown, there is a commitment to land, even during the season of sea ice presence.

scholarly journals Observation of polar bear (Ursus maritimus) feeding on Svalbard reindeer (Rangifer tarandus platyrhyncus) – exceptional behaviour or upcoming trend?

2018 ◽  
Vol 8 (2) ◽  
pp. 243-248
Author(s):  
Jan Kavan
Keyword(s):  
Sea Ice ◽  
Polar Bear ◽  
Rangifer Tarandus ◽  
Ursus Maritimus ◽  
Svalbard Reindeer

A polar bear (Ursus maritimus) was observed feeding on Svalbard reindeer (Rangifer tarandus platyrhyncus) on September 3rd 2018 near Skansbukta, central Svalbard. A well-developed male was observed to rest nearby and feed on fresh reindeer carcass. Polar bear hunting a reindeer is rather an exceptional behaviour at present, but could become more frequent with drastic decline of sea ice and thus loss of traditional hunting areas with presence of seals – the usual prey.

scholarly journals Iñupiaq Knowledge of Polar Bears (Ursus maritimus) in the Southern Beaufort Sea, Alaska

ARCTIC ◽  
2021 ◽  
Vol 74 (3) ◽  
pp. 239-257
Author(s):  
Karyn D. Rode ◽  
Hannah Voorhees ◽  
Henry P. Huntington ◽  
George M. Durner
Keyword(s):  
Sea Ice ◽  
Polar Bear ◽  
Late Summer ◽  
Beaufort Sea ◽  
Ursus Maritimus ◽  
The Arctic ◽  
Polar Bears ◽  
Structured Interviews ◽  
Ice Breakup ◽  
Pack Ice

Successful wildlife management depends upon coordination and consultation with local communities. However, much of the research used to inform management is often derived solely from data collected directly from wildlife. Indigenous people living in the Arctic have a close connection to their environment, which provides unique opportunities to observe their environment and the ecology of Arctic species. Further, most northern Arctic communities occur within the range of polar bears (nanuq, Ursus maritimus) and have experienced significant climatic changes. Here, we used semi-structured interviews from 2017 to 2019 to document Iñupiaq knowledge of polar bears observed over four decades in four Alaskan communities in the range of the Southern Beaufort Sea polar bear subpopulation: Wainwright, Utqiaġvik, Nuiqsut, and Kaktovik. All but one of 47 participants described directional and notable changes in sea ice, including earlier ice breakup, later ice return, thinner ice, and less multiyear pack ice. These changes corresponded with observations of bears spending more time on land during the late summer and early fall in recent decades—observations consistent with scientific and Indigenous knowledge studies in Alaska, Canada, and Greenland. Participants noted that polar bear and seal body condition and local abundance either varied geographically or exhibited no patterns. However, participants described a recent phenomenon of bears being exhausted and lethargic when arriving on shore in the summer and fall after extensive swims from the pack ice. Further, several participants suggested that maternal denning is occurring more often on land than sea ice. Participants indicated that village and regional governments are increasingly challenged to obtain resources needed to keep their communities safe as polar bears spend more time on land, an issue that is likely to be exacerbated both in this region and elsewhere as sea ice loss continues. 

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