POLAR BEAR DIETS AND ARCTIC MARINE FOOD WEBS: INSIGHTS FROM FATTY ACID ANALYSIS
We used quantitative fatty acid signature analysis (QFASA) to examine the diets of 1738 individual polar bears (Ursus maritimus) sampled across the Canadian Arctic over a 30-year span. Polar bear foraging varied over large and small spatial and temporal scales, and between demographic groups. Diets...
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ftdatacite:10.6084/m9.figshare.c.3309405.v1 2023-05-15T14:54:27+02:00 POLAR BEAR DIETS AND ARCTIC MARINE FOOD WEBS: INSIGHTS FROM FATTY ACID ANALYSIS Thiemann, Gregory W. Iverson, Sara J. Stirling, Ian 2016 https://dx.doi.org/10.6084/m9.figshare.c.3309405.v1 https://figshare.com/collections/POLAR_BEAR_DIETS_AND_ARCTIC_MARINE_FOOD_WEBS_INSIGHTS_FROM_FATTY_ACID_ANALYSIS/3309405/1 unknown Figshare https://dx.doi.org/10.1890/07-1050.1 https://dx.doi.org/10.6084/m9.figshare.c.3309405 CC-BY http://creativecommons.org/licenses/by/3.0/us CC-BY Environmental Science Ecology FOS Biological sciences Collection article 2016 ftdatacite https://doi.org/10.6084/m9.figshare.c.3309405.v1 https://doi.org/10.1890/07-1050.1 https://doi.org/10.6084/m9.figshare.c.3309405 2021-11-05T12:55:41Z We used quantitative fatty acid signature analysis (QFASA) to examine the diets of 1738 individual polar bears (Ursus maritimus) sampled across the Canadian Arctic over a 30-year span. Polar bear foraging varied over large and small spatial and temporal scales, and between demographic groups. Diets in every subpopulation were dominated by ringed seals (Phoca hispida) and, in the eastern Arctic, secondarily by harp seals (Pagophilus groenlandica). Beluga whales (Delphinapterus leucas) were an important food source for bears in the High Arctic, which is consistent with previous anecdotal reports. Foraging patterns were most similar among neighboring subpopulations with similar prey assemblages, but also differed geographically within Western Hudson Bay. The sexual size dimorphism of polar bears had an important effect on foraging, as large bearded seals (Erignathus barbatus) and walruses (Odobenus rosmarus) were consumed most often by older, male bears, whereas ringed seals and, where available, harbor seals (P. vitulina) were most important to younger age classes. Larger, older bears also had the greatest dietary diversity, apparently because of their ability to include larger-bodied prey. During spring and summer, polar bears in some areas increased predation on migratory harp seals and beluga whales. In Western Hudson Bay, bearded seal consumption declined between 1995 and 2001 for both male and female bears and continued to decline among females up to the most recent sampling (2004). Ringed seal consumption in Western Hudson Bay increased between 1998 and 2001, perhaps in response to increased ringed seal productivity, but was not significantly affected by date of sea-ice breakup. Overall, our data indicate that polar bears are capable of opportunistically altering their foraging to take advantage of locally abundant prey, or to some degree compensating for a decline in a dominant prey species. However, in other areas polar bears are dependent on the availability of ringed and bearded seals. Recent population data suggest that polar bears with the most specialized diets may be most vulnerable to climate-related changes in ice conditions. The results of this large-scale, ecosystem-based study indicate a complex relationship between sea-ice conditions, prey population dynamics, and polar bear foraging. Article in Journal/Newspaper Arctic bearded seal Beluga Beluga* Delphinapterus leucas Erignathus barbatus Hudson Bay Odobenus rosmarus Phoca hispida ringed seal Sea ice Ursus maritimus walrus* DataCite Metadata Store (German National Library of Science and Technology) Arctic Hudson Hudson Bay |
institution |
Open Polar |
collection |
DataCite Metadata Store (German National Library of Science and Technology) |
op_collection_id |
ftdatacite |
language |
unknown |
topic |
Environmental Science Ecology FOS Biological sciences |
spellingShingle |
Environmental Science Ecology FOS Biological sciences Thiemann, Gregory W. Iverson, Sara J. Stirling, Ian POLAR BEAR DIETS AND ARCTIC MARINE FOOD WEBS: INSIGHTS FROM FATTY ACID ANALYSIS |
topic_facet |
Environmental Science Ecology FOS Biological sciences |
description |
We used quantitative fatty acid signature analysis (QFASA) to examine the diets of 1738 individual polar bears (Ursus maritimus) sampled across the Canadian Arctic over a 30-year span. Polar bear foraging varied over large and small spatial and temporal scales, and between demographic groups. Diets in every subpopulation were dominated by ringed seals (Phoca hispida) and, in the eastern Arctic, secondarily by harp seals (Pagophilus groenlandica). Beluga whales (Delphinapterus leucas) were an important food source for bears in the High Arctic, which is consistent with previous anecdotal reports. Foraging patterns were most similar among neighboring subpopulations with similar prey assemblages, but also differed geographically within Western Hudson Bay. The sexual size dimorphism of polar bears had an important effect on foraging, as large bearded seals (Erignathus barbatus) and walruses (Odobenus rosmarus) were consumed most often by older, male bears, whereas ringed seals and, where available, harbor seals (P. vitulina) were most important to younger age classes. Larger, older bears also had the greatest dietary diversity, apparently because of their ability to include larger-bodied prey. During spring and summer, polar bears in some areas increased predation on migratory harp seals and beluga whales. In Western Hudson Bay, bearded seal consumption declined between 1995 and 2001 for both male and female bears and continued to decline among females up to the most recent sampling (2004). Ringed seal consumption in Western Hudson Bay increased between 1998 and 2001, perhaps in response to increased ringed seal productivity, but was not significantly affected by date of sea-ice breakup. Overall, our data indicate that polar bears are capable of opportunistically altering their foraging to take advantage of locally abundant prey, or to some degree compensating for a decline in a dominant prey species. However, in other areas polar bears are dependent on the availability of ringed and bearded seals. Recent population data suggest that polar bears with the most specialized diets may be most vulnerable to climate-related changes in ice conditions. The results of this large-scale, ecosystem-based study indicate a complex relationship between sea-ice conditions, prey population dynamics, and polar bear foraging. |
format |
Article in Journal/Newspaper |
author |
Thiemann, Gregory W. Iverson, Sara J. Stirling, Ian |
author_facet |
Thiemann, Gregory W. Iverson, Sara J. Stirling, Ian |
author_sort |
Thiemann, Gregory W. |
title |
POLAR BEAR DIETS AND ARCTIC MARINE FOOD WEBS: INSIGHTS FROM FATTY ACID ANALYSIS |
title_short |
POLAR BEAR DIETS AND ARCTIC MARINE FOOD WEBS: INSIGHTS FROM FATTY ACID ANALYSIS |
title_full |
POLAR BEAR DIETS AND ARCTIC MARINE FOOD WEBS: INSIGHTS FROM FATTY ACID ANALYSIS |
title_fullStr |
POLAR BEAR DIETS AND ARCTIC MARINE FOOD WEBS: INSIGHTS FROM FATTY ACID ANALYSIS |
title_full_unstemmed |
POLAR BEAR DIETS AND ARCTIC MARINE FOOD WEBS: INSIGHTS FROM FATTY ACID ANALYSIS |
title_sort |
polar bear diets and arctic marine food webs: insights from fatty acid analysis |
publisher |
Figshare |
publishDate |
2016 |
url |
https://dx.doi.org/10.6084/m9.figshare.c.3309405.v1 https://figshare.com/collections/POLAR_BEAR_DIETS_AND_ARCTIC_MARINE_FOOD_WEBS_INSIGHTS_FROM_FATTY_ACID_ANALYSIS/3309405/1 |
geographic |
Arctic Hudson Hudson Bay |
geographic_facet |
Arctic Hudson Hudson Bay |
genre |
Arctic bearded seal Beluga Beluga* Delphinapterus leucas Erignathus barbatus Hudson Bay Odobenus rosmarus Phoca hispida ringed seal Sea ice Ursus maritimus walrus* |
genre_facet |
Arctic bearded seal Beluga Beluga* Delphinapterus leucas Erignathus barbatus Hudson Bay Odobenus rosmarus Phoca hispida ringed seal Sea ice Ursus maritimus walrus* |
op_relation |
https://dx.doi.org/10.1890/07-1050.1 https://dx.doi.org/10.6084/m9.figshare.c.3309405 |
op_rights |
CC-BY http://creativecommons.org/licenses/by/3.0/us |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.6084/m9.figshare.c.3309405.v1 https://doi.org/10.1890/07-1050.1 https://doi.org/10.6084/m9.figshare.c.3309405 |
_version_ |
1766326181918932992 |