Unusual Predation Attempts of Polar Bears on Ringed Seals in the Southern Beaufort Sea: Possible Significance of Changing Spring Ice Conditions

In April and May 2003 through 2006, unusually rough and rafted sea ice extended for several tens of kilometres offshore in the southeastern Beaufort Sea from about Atkinson Point to the Alaska border. Hunting success of polar bears (Ursus maritimus) seeking seals was low despite extensive searching for prey. It is unknown whether seals were less abundant in comparison to other years or less accessible because they maintained breathing holes below rafted ice rather than snowdrifts, or whether some other factor was involved. However, we found 13 sites where polar bears had clawed holes through rafted ice in attempts to capture ringed seals (Phoca hispida) in 2005 through 2006 and another site during an additional research project in 2007. Ice thickness at the 12 sites that we measured averaged 41 cm. These observations, along with cannibalized and starved polar bears found on the sea ice in the same general area in the springs of 2004 through 2006, suggest that during those years, polar bears in the southern Beaufort Sea were nutritionally stressed. Searches made farther north during the same period and using the same methods produced no similar observations near Banks Island or in Amundsen Gulf. A possible underlying ecological explanation is a decadal-scale downturn in seal populations. But a more likely explanation is major changes in the sea-ice and marine environment resulting from record amounts and duration of open water in the Beaufort and Chukchi seas, possibly influenced by climate warming. Because the underlying causes of observed changes in polar bear body condition and foraging behaviour are unknown, further study is warranted.En avril et en mai des années 2003 à 2006, de la glace de mer inhabituellement raboteuse et entassée s’est étendue sur plusieurs dizaines de kilomètres au large du sud-est de la mer de Beaufort, à partir de la pointe Atkinson environ jusqu’à la frontière de l’Alaska. Les ours polaires (Ursus maritimus) avaient donc du mal à attraper des phoques malgré la chasse intense. On ne sait pas si les phoques s’y trouvaient en moins grande abondance par rapport aux autres années ou s’ils étaient moins accessibles parce qu’ils maintenaient des trous d’air sous la glace entassée plutôt que dans les congères, ou si un autre facteur entrait en jeu. Cependant, de 2005 à 2006, on a repéré 13 endroits où les ours polaires avaient griffé des trous dans la glace entassée pour essayer d’attraper les phoques annelés (Phoca hispida), puis un autre endroit dans le cadre d’un autre projet de recherche en 2007. Aux 12 endroits mesurés, l’épaisseur de la glace atteignait 41 cm en moyenne. Ces observations, en plus des observations d’ours polaires cannibalisés et d’ours polaires affamés trouvés sur la glace de mer dans à peu près la même région du printemps 2004 au printemps 2006, laissent croire que pendant ces années, les ours polaires du sud de la mer de Beaufort éprouvaient du stress alimentaire. Des recherches effectuées plus au nord pendant cette même période, recherches réalisées à l’aide des mêmes méthodes, n’ont pas permis d’aboutir à des observations similaires près de l’île de Banks ou du golfe Amundsen. Du point de vue écologique, une explication sous-jacente consisterait en un fléchissement décadaire des populations de phoques. Cependant, une explication plus plausible consisterait en des changements majeurs caractérisant la glace de mer et le milieu marin découlant de quantités et de durées records d’eau libre dans les mers de Beaufort et de Chukchi, ce qui pourrait être le résultat du réchauffement climatique. Puisqu’on ne connaît pas les causes sous-jacentes des changements observés sur le plan de l’état du corps et des comportements alimentaires des ours polaires, des recherches plus poussées pourraient être justifiées

Ringed Seal Monitoring and Planning Workshop

Ringed seals (Pusa hispida) are the most abundant seal in the Arctic. They are an important traditional food for Inuit throughout Nunavut, and ringed seal skins are an important resource used for clothing and other products. Ringed seals rely on first-year sea ice as a platform for resting and moulting (shedding old hair and replacing it with new growth) and they construct birth lairs beneath the snow for protecting pups against both predators and weather. In many parts of their range, ringed seals feed on fishes and other organisms associated with epontic (under-ice) biological communities. Ringed seals are therefore an important species to monitor as they are vulnerable to changes in environmental conditions, such as ice extent and thickness, snowfall, and abundance of other marine species. Changes in ringed seal health will also affect the health of Inuit communities. In particular, there have been advisories on the consumption of ringed seal liver as a result of contaminants and pollutants. Ringed seal research programs exist across the Canadian Arctic, especially in the eastern Arctic, and involve the participation of local hunters in the collection of samples and data. There is growing interest among communities and researchers in expanding both the focus of research and the communities involved. We held a workshop in Iqaluit, NU on March 6-7, 2014, that invited researchers, managers, community members, and students to discuss knowledge and issues around ringed seal research in Nunavut. The purpose of the workshop was to provide an opportunity to exchange knowledge, identify information gaps and priorities, plan for future collaborative and community-based research on ringed seals, as well as identify management and community concerns. The workshop involved 10 community members from across Nunavut; 14 researchers from universities and government; 5 staff from Nunavut government departments and management organizations; 2 representatives from Nunavut Tunngavik Incorporated; a representative from the Nunavut Research Institute; and 14 students from the Environmental Technology Program (ETP) at Nunavut Arctic College. The workshop structure involved breakout sessions during which small groups shared their perspectives about specific topics, followed by plenary sessions where each breakout group reported the main points from their discussions to the full group. Breakout sessions focused on 1) identifying knowledge priorities, 2) the communication and use of knowledge, and 3) identifying a set of next steps for future action. Questions that were brought up throughout the plenary sessions were also recorded, and an additional breakout session was dedicated to providing groups with a chance to respond to those questions that were relevant to them.Aboriginal Affairs and Northern Development Canada (Nunavut General Monitoring Plan and Northern Contaminants Program), Government of Nunavut, Nunavut Wildlife Management Board, World Wildlife Fund Canada, Environment Canad

Comparing temporal patterns in body condition of ringed seals living within their core geographic range with those living at the edge

Ecological theory suggests that demographic responses by populations to environmental change vary depending on whether individuals inhabit central or peripheral regions within the species’ geographic range. Here, we tested this prediction by comparing a population of ringed seals Pusa hispida located at high latitudes as part of their core range (core) with a population located at the southern extremity of their range (peripheral). First, we compared the two regions’ environmental trends in timing of sea-ice breakup and freeze-up, open-water duration and the North Atlantic Oscillation (NAO). We found that the core region shifted to progressively warmer conditions in the early 1990s; whereas, in the peripheral region, the warming trend shifted in 1999 to one with no warming trend but high inter-annual variability. Next, we examined how body condition, inferred from blubber depth, responded to temporal changes in sea-ice and climatic variables – variables that have been shown to influence ringed seal demography. Core seals displayed minimal seasonal changes in body condition; whereas peripheral seals displayed a 20–60% amplitude seasonal change in body condition with a phase shift to earlier initiation of fat accumulation and loss. Finally, we tested for interannual differences and found that both core and peripheral seals responded similarly with decreased body condition following more positive NAO. Environmental variables influenced body condition in opposite directions between the two regions with core seals declining in body condition with later spring breakup and shorter open-water duration, whereas peripheral seals showed opposite relationships. Seals living at the core likely benefit from an evolved match between adaptation and environmental variation resulting in dampened seasonal and interannual fluctuations in body condition. Knowledge of how different populations respond to environmental change depending on geographic location within a species range can assist in anticipating population specific responses to climate warming

Brane-World Gravity

The observable universe could be a 1+3-surface (the "brane") embedded in a 1+3+\textit{d}-dimensional spacetime (the "bulk"), with Standard Model particles and fields trapped on the brane while gravity is free to access the bulk. At least one of the \textit{d} extra spatial dimensions could be very large relative to the Planck scale, which lowers the fundamental gravity scale, possibly even down to the electroweak ($\sim$ TeV) level. This revolutionary picture arises in the framework of recent developments in M theory. The 1+10-dimensional M theory encompasses the known 1+9-dimensional superstring theories, and is widely considered to be a promising potential route to quantum gravity. At low energies, gravity is localized at the brane and general relativity is recovered, but at high energies gravity "leaks" into the bulk, behaving in a truly higher-dimensional way. This introduces significant changes to gravitational dynamics and perturbations, with interesting and potentially testable implications for high-energy astrophysics, black holes, and cosmology. Brane-world models offer a phenomenological way to test some of the novel predictions and corrections to general relativity that are implied by M theory. This review analyzes the geometry, dynamics and perturbations of simple brane-world models for cosmology and astrophysics, mainly focusing on warped 5-dimensional brane-worlds based on the Randall--Sundrum models. We also cover the simplest brane-world models in which 4-dimensional gravity on the brane is modified at \emph{low} energies -- the 5-dimensional Dvali--Gabadadze--Porrati models. Then we discuss co-dimension two branes in 6-dimensional models.Comment: A major update of Living Reviews in Relativity 7:7 (2004) "Brane-World Gravity", 119 pages, 28 figures, the update contains new material on RS perturbations, including full numerical solutions of gravitational waves and scalar perturbations, on DGP models, and also on 6D models. A published version in Living Reviews in Relativit

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

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 additional role of sea ice as a potential, indirect, source of energy to bears has been overlooked. Here we used the highly branched isoprenoid lipid biomarker-based index (H-Print) approach in combination with quantitative fatty acid signature analysis to show that sympagic (sea ice-associated), rather than pelagic, carbon contributions dominated the marine component of polar bear diet (72-100%; 99% CI, n = 55), irrespective of differences in diet composition. The lowest mean estimates of sympagic carbon were found in Baffin Bay bears, which were also exposed to the most rapidly increasing open water season. Therefore, our data illustrate that for future Arctic ecosystems that are likely to be characterised by reduced sea ice cover, polar bears will not only be impacted by a change in their physical habitat, but also potentially in the supply of energy to the ecosystems upon which they depend. This data represents the first quantifiable baseline that is critical for the assessment of likely ongoing changes in energy supply to Arctic predators as we move into an increasingly uncertain future for polar ecosystems

Trans fatty acids provide evidence of anthropogenic feeding by black bears

Bears (Ursus spp.) that become conditioned to anthropogenic food sources pose a risk to human safety and generally need to be relocated, rehabilitated, or destroyed. Identifying food-conditioned bears may be difficult if the animal is not captured or killed while immediately engaged in the nuisance behavior. Fatty acid signature analysis has been used to examine the dietary habits of bears and other carnivores and is based on the predictable incorporation of ingested fatty acids into the consumer’s fat stores. Unusual fatty acids that are available in only a few food types may be particularly useful dietary markers. In this study, we tested the hypothesis that trans fatty acids present in many processed foods could serve as markers of anthropogenic foraging by black bears (Ursus americanus). Among 13 bears that were killed in western and central Colorado, trans fatty acids were more abundant in conflict bears than in non-conflict bears. Further, the abundance of trans fatty acids in bear fat appeared to be correlated with the intensity of bear–human conflict. We conclude that the trophic transfer of trans fatty acids can provide valuable insights into the ecological, demographic, and anthropogenic factors that contribute to bear–human conflict

Drivers and consequences of apex predator diet composition in the Canadian Beaufort Sea

Polar bears (Ursus maritimus) rely on annual sea ice as their primary habitat for hunting marine mammal prey. Given their long lifespan, wide geographic distribution, and position at the top of the Arctic marine food web, the diet composition of polar bears can provide insights into temporal and spatial ecosystem dynamics related to climate-mediated sea ice loss. Polar bears with the greatest ecological constraints on diet composition may be most vulnerable to climate-related changes in ice conditions and prey availability. We used quantitative fatty acid signature analysis (QFASA) to estimate the diets of polar bears (n = 419) in two western Canadian Arctic subpopulations (Northern Beaufort Sea and Southern Beaufort Sea) from 1999 to 2015. Polar bear diets were dominated by ringed seal (Pusa hispida), with interannual, seasonal, age- and sex-specific variation. Foraging area and sea ice conditions also affected polar bear diet composition. Most variation in bear diet was explained by longitude, reflecting spatial variation in prey availability. Sea ice conditions (extent, thickness, and seasonal duration) declined throughout the study period, and date of sea ice break-up in the preceding spring was positively correlated with female body condition and consumption of beluga whale (Delphinapterus leucas), suggesting that bears foraged on beluga whales during entrapment events. Female body condition was positively correlated with ringed seal consumption, and negatively correlated with bearded seal consumption. This study provides insights into the complex relationships between declining sea ice habitat and the diet composition and foraging success of a wide-ranging apex predator

Traditional Ecological Knowledge of Polar Bears in the Northern Eeyou Marine Region, Québec, Canada + Supplementary Appendix 1 (See Article Tools)

Polar bears are important socio-cultural symbols in the communities of the Eeyou Marine Region (EMR) in northwestern Québec, Canada. Members of the Cree communities in this region are generally not active polar bear hunters, but they encounter polar bears when fishing, trapping, or hunting during the ice-free season. A growing body of scientific evidence suggests that reduced annual sea ice cover in Hudson Bay has led to declines in body condition of polar bears in the local Southern Hudson Bay subpopulation and to a population decline in the neighboring Western Hudson Bay subpopulation. In June 2012, we conducted 15 semi-directed interviews on the subject of polar bear biology and climate change with local elders and hunters in three communities in the northern EMR: Wemindji, Chisasibi, and Whapmagoostui. The interviews held in Whapmagoostui included informants from Kuujjuarapik, the adjacent Inuit community. The interviews addressed knowledge gaps in the Recovery Strategy for Polar Bear in Ontario. Transcripts of the interviews were coded thematically and analyzed using both qualitative and quantitative methods. The interviews revealed important insights into polar bear distribution, terrestrial habitat use, denning, and foraging patterns. Participants were unanimous in their recognition of a warming climate and prolonged ice-free season in the area in recent years. However, communities differed in their observations on other issues, with latitudinal trends evident in observations of polar bear distribution, denning activity, and foraging habits. Communities also differed in their perception of the prevalence of problem polar bears and the conservation status of the species, with one-third of participants reporting that polar bears will be unaffected by, or even benefit from, longer ice-free periods. A majority of participants indicated that the local polar bear population was stable or increasing. Interviewees also identified future research priorities pertinent to the communities, and provided comments on the methods employed by polar bear biologists. Our results demonstrate that communities in the EMR have important knowledge about polar bear ecology and illustrate the unique opportunities and challenges of combining traditional ecological knowledge with wildlife science in the context of a rapidly changing subarctic environment.L’ours blanc revêt un caractère socioculturel important pour les communautés de la Région marine d’Eeyou (RME), située dans le nord-ouest de la province de Québec, au Canada. Bien que les Cris de ces communautés ne soient pas reconnus pour chasser particulièrement l’ours blanc, ils partagent le territoire avec l’ours blanc lors de leurs déplacements et activités de chasse, de pêche et de trappe. Un nombre croissant de preuves scientifiques suggère que la réduction annuelle de la couverture de glace dans la baie d’Hudson aurait causé une dégradation de la condition physique des ours blancs de la sous-population sud de la baie d’Hudson et un déclin de la sous-population voisine, dans l’ouest de la baie d’Hudson. En juin 2012, nous avons réalisé une série de 15 entrevues semi-dirigées concernant la biologie de l’ours blanc et les changements climatiques avec des aînés et des chasseurs de trois communautés de la portion nordique de la RME : Wemindji, Chisasibi et Whapmagoostui. Les entrevues tenues à Whapmagoostui ont inclus des répondants du village inuit adjacent, Kuujjuarapik. Les entrevues abordaient des lacunes au niveau des connaissances, telles que déterminées par le Programme de rétablissement de l’ours polaire en Ontario. Les entrevues ont été transcrites et codées par thèmes afin d’être analysées suivant des méthodes qualitatives et quantitatives. Les entrevues révèlent d’importantes informations relativement aux connaissances sur la distribution, l’utilisation des habitats terrestres, les aires de mise bas et les habitudes alimentaires des ours blancs. Les participants ont unanimement constaté le réchauffement du climat et la prolongation de la période libre de glace au cours des dernières années sur leur territoire d’activités. Cependant, les points de vue des participants diffèrent pour ce qui est de certains enjeux, selon un gradient latitudinal évident, concernant la distribution, les activités de mise bas et les habitudes alimentaires de l’espèce. Les perceptions des communautés diffèrent aussi relativement à la prévalence des ours blancs problématiques et en ce qui concerne le statut de conservation de l’espèce, avec le tiers des participants jugeant que les ours blancs ne seraient pas affectés, ou pourraient même bénéficier, d’une plus longue période libre de glace. Une majorité de participants indique que la population locale d’ours blancs est stable ou en augmentation. Enfin, les répondants ont indiqué les priorités de recherches pertinentes à leur communauté et partagé des commentaires sur les méthodes employées par les biologistes. Les résultats montrent que les communautés de la RME possèdent des connaissances importantes concernant l’écologie de l’ours blanc, illustrant ainsi les opportunités et les défis afin de combiner ces données à celles des sciences biologiques, ceci dans un contexte de changement rapide de l’environnement subarctique

Appendix A. A table summarizing the bear subpopulation distribution of samples from independent-age (>2.5 yr) polar bears collected across the Canadian Arctic from 1972 to 2004 and used to examine interannual changes in diets.

A table summarizing the bear subpopulation distribution of samples from independent-age (>2.5 yr) polar bears collected across the Canadian Arctic from 1972 to 2004 and used to examine interannual changes in diets