Polar bear predatory behaviour reveals seascape distribution of ringed seal lairs

Pilfold, Nicholas W.; Derocher, Andrew E.; Stirling, Ian; Richardson, Evan S.

doi:10.1007/s10144-013-0396-z

Cited by 64 publications

(35 citation statements)

References 59 publications

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“…Similar to our results, Mauritzen et al [12] found that the probability of using high sea ice concentrations decreased when bears were located in areas with high sea ice concentrations, but exhibited the opposite pattern when bears were in areas with low concentrations of sea ice. Polar bears live in a highly dynamic environment, requiring them to respond by constantly moving to areas with conditions suitable for finding and capturing prey [16,36]. The lack of change in functional responses between periods implies that polar bears are making similar decisions in response to their local conditions as they did before sea ice changes.…”

Section: Discussionmentioning

confidence: 99%

“…Future research should also focus on relating polar bear space use to ice metrics that are more directly related to seal presence and abundance (e.g. presence/absence of pressure ridges; [16]). …”

Section: Discussionmentioning

confidence: 99%

“…shifting to deeper water as ice retreats). While polar bear prey currently prefer the shallow waters over the continental shelf [15][16][17], if changing ice and currents in the Arctic Ocean made deeper waters more productive for prey, then we might expect prey to begin using these areas with greater frequency. This would imply that loss of sea ice in summer would have a more limited effect on polar bears than currently thought [18].…”

Section: Introductionmentioning

confidence: 99%

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Invariant polar bear habitat selection during a period of sea ice loss

et al. 2016

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Climate change is expected to alter many species' habitat. A species' ability to adjust to these changes is partially determined by their ability to adjust habitat selection preferences to new environmental conditions. Sea ice loss has forced polar bears (Ursus maritimus) to spend longer periods annually over less productive waters, which may be a primary driver of population declines. A negative population response to greater time spent over less productive water implies, however, that prey are not also shifting their space use in response to sea ice loss. We show that polar bear habitat selection in the Chukchi Sea has not changed between periods before and after significant sea ice loss, leading to a 75% reduction of highly selected habitat in summer. Summer was the only period with loss of highly selected habitat, supporting the contention that summer will be a critical period for polar bears as sea ice loss continues. Our results indicate that bears are either unable to shift selection patterns to reflect new prey use patterns or that there has not been a shift towards polar basin waters becoming more productive for prey. Continued sea ice loss is likely to further reduce habitat with population-level consequences for polar bears.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Invariant polar bear habitat selection during a period of sea ice loss

et al. 2016

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“…Although that explanation seems reasonable given both the current and historical distributions of these various predators, the relative importance of polar bear predation is uncertain because of the confounding influence of aboriginal peoples in the Arctic. It appears, however, that the distribution of ringed seal lairs is driven at least partially by the risk of predation from polar bears (102).…”

Section: Pinnipedsmentioning

confidence: 99%

Megafaunal Impacts on Structure and Function of Ocean Ecosystems

Estes

Heithaus

McCauley

et al. 2016

Annu. Rev. Environ. Resour.

183

167

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Here, we identify the extant species of marine megafauna (>45 kg maximum reported mass), provide a conceptual template for the ways in which these species influence the structure and function of ocean ecosystems, and review the published evidence for such influences. Ecological influences of more than 90% of the 338 known species of extant ocean megafauna are unstudied and thus unknown. The most widely known effect of those few species that have been studied is direct prey limitation, which occurs through consumption and risk avoidance behavior. Consumer-prey interactions result in indirect effects that extend through marine ecosystems to other species and ecological processes. Marine megafauna transport energy, nutrients, and other materials vertically and horizontally through the oceans, often over long distances. The functional relationships between these various ecological impacts and megafauna population densities, in the few well-studied cases, are characterized by phase shifts and hysteresis.

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“…The influence of ringed seal whelping was also observable at inter-annual scales, with total kill frequency positively correlated to years of high ringed seal natality, whereas adults were killed in higher proportion in years when natality was low. Employing locations of seal kills and attempted hunts at ringed seal subnivean lairs, Pilfold et al (2013) showed that polar bears selected for active areas of sea ice near the floe edge when hunting. Ringed seal whelping areas were located over a range of habitats, and the distribution was correlated with their natality rates.…”

Section: Polar Bear Foraging Ecology In the Beaufort Seamentioning

confidence: 99%