Polar bear diet composition reveals spatiotemporal distribution of Arctic marine mammals across Nunavut, Canada

Climate warming and associated physical and biological changes will likely force widespread species redistribution, particularly in polar environments. However, tracking such distributional shifts is difficult. The dietary habits of apex predators, like polar bears (Ursus maritimus), may provide ear...

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Autores principales: Melissa P. Galicia, Gregory W. Thiemann, Markus G. Dyck, Steven H. Ferguson
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Publicado: Elsevier 2021
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spelling oai:doaj.org-article:66e810957203458080189e7358a79ba72021-12-01T05:01:13ZPolar bear diet composition reveals spatiotemporal distribution of Arctic marine mammals across Nunavut, Canada1470-160X10.1016/j.ecolind.2021.108245https://doaj.org/article/66e810957203458080189e7358a79ba72021-12-01T00:00:00Zhttp://www.sciencedirect.com/science/article/pii/S1470160X21009109https://doaj.org/toc/1470-160XClimate warming and associated physical and biological changes will likely force widespread species redistribution, particularly in polar environments. However, tracking such distributional shifts is difficult. The dietary habits of apex predators, like polar bears (Ursus maritimus), may provide early signals of distributional change in prey populations. We used harvest-based sampling to investigate the spatial feeding patterns of polar bears across Nunavut from 2010 to 2018 (n = 1570) and identify spatiotemporal clusters of different prey based on predator diet estimates. Quantitative fatty acid signature analysis and the Getis-Ord Gi* statistic identified spatial clusters of high or low dietary proportions (i.e., “hot spots” and “cold spots”) reflecting seasonal and spatial availability of prey. Ringed seal (Pusa hispida) was the primary prey of bears throughout Nunavut followed by bearded seal (Erignathus barbatus), although proportional consumption varied spatially. A consistent ringed seal consumption hot spot was found in Gulf of Boothia indicating the importance of year-round availability of ringed seals. Spatial clusters of bearded seal and Atlantic walrus (Odobenus rosmarus rosmarus) throughout Foxe Basin suggested overlapping seasonal distributions and high regional abundance. Bears had consistently high dietary levels of harbour seal (Phoca vitulina) around Southampton Island and along the western coast of Hudson Bay suggesting a possible year-round concentration of this prey. Hot spots of harp seal (Pagophilus groenlandicus) consumption were evident throughout Davis Strait and a spring-summer hot spot around Jones Sound was consistent with harp seal migratory patterns. Year-round beluga whale (Delphinapterus leucas) hot spots were found along eastern Baffin Island and southern Viscount Melville Sound providing new knowledge of local conditions that promote polar bear predation or scavenging. Narwhal (Monodon monoceros) were less susceptible to predation with only one spatial cluster of high consumption appearing during spring-summer in Barrow Strait. Bowhead whale (Balaena mysticetus) hot spots occurred around south-western Foxe Basin and seasonally in southern Viscount Melville Sound suggesting carcasses are locally accessible to bears and may act as a supplemental food source in particular areas and seasons. The congruence of polar bear feeding habits and known prey distribution suggests polar bears serve as ecological indicators and ongoing monitoring of their diets may reveal regional and broad-scale changes in prey population distributions and Arctic ecosystem functioning.Melissa P. GaliciaGregory W. ThiemannMarkus G. DyckSteven H. FergusonElsevierarticlePolar bearsArcticMarine mammalsDietSpatial distributionQuantitative fatty acid signature analysis (QFASA)EcologyQH540-549.5ENEcological Indicators, Vol 132, Iss , Pp 108245- (2021)
institution DOAJ
collection DOAJ
language EN
topic Polar bears
Arctic
Marine mammals
Diet
Spatial distribution
Quantitative fatty acid signature analysis (QFASA)
Ecology
QH540-549.5
spellingShingle Polar bears
Arctic
Marine mammals
Diet
Spatial distribution
Quantitative fatty acid signature analysis (QFASA)
Ecology
QH540-549.5
Melissa P. Galicia
Gregory W. Thiemann
Markus G. Dyck
Steven H. Ferguson
Polar bear diet composition reveals spatiotemporal distribution of Arctic marine mammals across Nunavut, Canada
description Climate warming and associated physical and biological changes will likely force widespread species redistribution, particularly in polar environments. However, tracking such distributional shifts is difficult. The dietary habits of apex predators, like polar bears (Ursus maritimus), may provide early signals of distributional change in prey populations. We used harvest-based sampling to investigate the spatial feeding patterns of polar bears across Nunavut from 2010 to 2018 (n = 1570) and identify spatiotemporal clusters of different prey based on predator diet estimates. Quantitative fatty acid signature analysis and the Getis-Ord Gi* statistic identified spatial clusters of high or low dietary proportions (i.e., “hot spots” and “cold spots”) reflecting seasonal and spatial availability of prey. Ringed seal (Pusa hispida) was the primary prey of bears throughout Nunavut followed by bearded seal (Erignathus barbatus), although proportional consumption varied spatially. A consistent ringed seal consumption hot spot was found in Gulf of Boothia indicating the importance of year-round availability of ringed seals. Spatial clusters of bearded seal and Atlantic walrus (Odobenus rosmarus rosmarus) throughout Foxe Basin suggested overlapping seasonal distributions and high regional abundance. Bears had consistently high dietary levels of harbour seal (Phoca vitulina) around Southampton Island and along the western coast of Hudson Bay suggesting a possible year-round concentration of this prey. Hot spots of harp seal (Pagophilus groenlandicus) consumption were evident throughout Davis Strait and a spring-summer hot spot around Jones Sound was consistent with harp seal migratory patterns. Year-round beluga whale (Delphinapterus leucas) hot spots were found along eastern Baffin Island and southern Viscount Melville Sound providing new knowledge of local conditions that promote polar bear predation or scavenging. Narwhal (Monodon monoceros) were less susceptible to predation with only one spatial cluster of high consumption appearing during spring-summer in Barrow Strait. Bowhead whale (Balaena mysticetus) hot spots occurred around south-western Foxe Basin and seasonally in southern Viscount Melville Sound suggesting carcasses are locally accessible to bears and may act as a supplemental food source in particular areas and seasons. The congruence of polar bear feeding habits and known prey distribution suggests polar bears serve as ecological indicators and ongoing monitoring of their diets may reveal regional and broad-scale changes in prey population distributions and Arctic ecosystem functioning.
format article
author Melissa P. Galicia
Gregory W. Thiemann
Markus G. Dyck
Steven H. Ferguson
author_facet Melissa P. Galicia
Gregory W. Thiemann
Markus G. Dyck
Steven H. Ferguson
author_sort Melissa P. Galicia
title Polar bear diet composition reveals spatiotemporal distribution of Arctic marine mammals across Nunavut, Canada
title_short Polar bear diet composition reveals spatiotemporal distribution of Arctic marine mammals across Nunavut, Canada
title_full Polar bear diet composition reveals spatiotemporal distribution of Arctic marine mammals across Nunavut, Canada
title_fullStr Polar bear diet composition reveals spatiotemporal distribution of Arctic marine mammals across Nunavut, Canada
title_full_unstemmed Polar bear diet composition reveals spatiotemporal distribution of Arctic marine mammals across Nunavut, Canada
title_sort polar bear diet composition reveals spatiotemporal distribution of arctic marine mammals across nunavut, canada
publisher Elsevier
publishDate 2021
url https://doaj.org/article/66e810957203458080189e7358a79ba7
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