Influence of sea ice dynamics on population energetics of Western Hudson Bay polar bears
Abstract The Arctic marine ecosystem has experienced extensive changes in sea ice dynamics, with significant effects on ice-dependent species such as polar bears (Ursus maritimus). We used annual estimates of the numbers of bears onshore in the core summering area, age/sex structure and body conditi...
Published in: | Conservation Physiology |
---|---|
Main Authors: | , , , , , |
Other Authors: | |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
Oxford University Press (OUP)
2020
|
Subjects: | |
Online Access: | http://dx.doi.org/10.1093/conphys/coaa132 http://academic.oup.com/conphys/article-pdf/8/1/coaa132/35268960/coaa132.pdf |
id |
croxfordunivpr:10.1093/conphys/coaa132 |
---|---|
record_format |
openpolar |
spelling |
croxfordunivpr:10.1093/conphys/coaa132 2023-10-01T03:54:20+02:00 Influence of sea ice dynamics on population energetics of Western Hudson Bay polar bears Johnson, Amy C Reimer, Jody R Lunn, Nicholas J Stirling, Ian McGeachy, David Derocher, Andrew E Cooke, Steven 2020 http://dx.doi.org/10.1093/conphys/coaa132 http://academic.oup.com/conphys/article-pdf/8/1/coaa132/35268960/coaa132.pdf en eng Oxford University Press (OUP) http://creativecommons.org/licenses/by/4.0/ Conservation Physiology volume 8, issue 1 ISSN 2051-1434 Management, Monitoring, Policy and Law Nature and Landscape Conservation Ecological Modeling Physiology journal-article 2020 croxfordunivpr https://doi.org/10.1093/conphys/coaa132 2023-09-08T10:50:15Z Abstract The Arctic marine ecosystem has experienced extensive changes in sea ice dynamics, with significant effects on ice-dependent species such as polar bears (Ursus maritimus). We used annual estimates of the numbers of bears onshore in the core summering area, age/sex structure and body condition data to estimate population energy density and storage energy in Western Hudson Bay polar bears from 1985 to 2018. We examined intra-population variation in energetic patterns, temporal energetic trends and the relationship between population energetics and sea ice conditions. Energy metrics for most demographic classes declined over time in relation to earlier sea ice breakup, most significantly for solitary adult females and subadult males, suggesting their greater vulnerability to nutritional stress than other age/sex classes. Temporal declines in population energy metrics were related to earlier breakup and longer lagged open-water periods, suggesting multi-year effects of sea ice decline. The length of the open-water period ranged from 102 to 166 days and increased significantly by 9.9 days/decade over the study period. Total population energy density and storage energy were significantly lower when sea ice breakup occurred earlier and the lagged open-water period was longer. At the earliest breakup and a lagged open-water period of 180 days, population energy density was predicted to be 33% lower than our minimum estimated energy density and population storage energy was predicted to be 40% lower than the minimum estimated storage energy. Consequently, over the study, the total population energy density declined by 53% (mean: 3668 ± 386 MJ kg-1/decade) and total population storage energy declined by 56% (mean: 435900 ± 46770 MJ/decade). This study provides insights into ecological mechanisms linking population responses to sea ice decline and highlights the significance of maintaining long-term research programs. Article in Journal/Newspaper Arctic Hudson Bay Sea ice Ursus maritimus Oxford University Press (via Crossref) Arctic Hudson Bay Hudson Conservation Physiology 8 1 |
institution |
Open Polar |
collection |
Oxford University Press (via Crossref) |
op_collection_id |
croxfordunivpr |
language |
English |
topic |
Management, Monitoring, Policy and Law Nature and Landscape Conservation Ecological Modeling Physiology |
spellingShingle |
Management, Monitoring, Policy and Law Nature and Landscape Conservation Ecological Modeling Physiology Johnson, Amy C Reimer, Jody R Lunn, Nicholas J Stirling, Ian McGeachy, David Derocher, Andrew E Influence of sea ice dynamics on population energetics of Western Hudson Bay polar bears |
topic_facet |
Management, Monitoring, Policy and Law Nature and Landscape Conservation Ecological Modeling Physiology |
description |
Abstract The Arctic marine ecosystem has experienced extensive changes in sea ice dynamics, with significant effects on ice-dependent species such as polar bears (Ursus maritimus). We used annual estimates of the numbers of bears onshore in the core summering area, age/sex structure and body condition data to estimate population energy density and storage energy in Western Hudson Bay polar bears from 1985 to 2018. We examined intra-population variation in energetic patterns, temporal energetic trends and the relationship between population energetics and sea ice conditions. Energy metrics for most demographic classes declined over time in relation to earlier sea ice breakup, most significantly for solitary adult females and subadult males, suggesting their greater vulnerability to nutritional stress than other age/sex classes. Temporal declines in population energy metrics were related to earlier breakup and longer lagged open-water periods, suggesting multi-year effects of sea ice decline. The length of the open-water period ranged from 102 to 166 days and increased significantly by 9.9 days/decade over the study period. Total population energy density and storage energy were significantly lower when sea ice breakup occurred earlier and the lagged open-water period was longer. At the earliest breakup and a lagged open-water period of 180 days, population energy density was predicted to be 33% lower than our minimum estimated energy density and population storage energy was predicted to be 40% lower than the minimum estimated storage energy. Consequently, over the study, the total population energy density declined by 53% (mean: 3668 ± 386 MJ kg-1/decade) and total population storage energy declined by 56% (mean: 435900 ± 46770 MJ/decade). This study provides insights into ecological mechanisms linking population responses to sea ice decline and highlights the significance of maintaining long-term research programs. |
author2 |
Cooke, Steven |
format |
Article in Journal/Newspaper |
author |
Johnson, Amy C Reimer, Jody R Lunn, Nicholas J Stirling, Ian McGeachy, David Derocher, Andrew E |
author_facet |
Johnson, Amy C Reimer, Jody R Lunn, Nicholas J Stirling, Ian McGeachy, David Derocher, Andrew E |
author_sort |
Johnson, Amy C |
title |
Influence of sea ice dynamics on population energetics of Western Hudson Bay polar bears |
title_short |
Influence of sea ice dynamics on population energetics of Western Hudson Bay polar bears |
title_full |
Influence of sea ice dynamics on population energetics of Western Hudson Bay polar bears |
title_fullStr |
Influence of sea ice dynamics on population energetics of Western Hudson Bay polar bears |
title_full_unstemmed |
Influence of sea ice dynamics on population energetics of Western Hudson Bay polar bears |
title_sort |
influence of sea ice dynamics on population energetics of western hudson bay polar bears |
publisher |
Oxford University Press (OUP) |
publishDate |
2020 |
url |
http://dx.doi.org/10.1093/conphys/coaa132 http://academic.oup.com/conphys/article-pdf/8/1/coaa132/35268960/coaa132.pdf |
geographic |
Arctic Hudson Bay Hudson |
geographic_facet |
Arctic Hudson Bay Hudson |
genre |
Arctic Hudson Bay Sea ice Ursus maritimus |
genre_facet |
Arctic Hudson Bay Sea ice Ursus maritimus |
op_source |
Conservation Physiology volume 8, issue 1 ISSN 2051-1434 |
op_rights |
http://creativecommons.org/licenses/by/4.0/ |
op_doi |
https://doi.org/10.1093/conphys/coaa132 |
container_title |
Conservation Physiology |
container_volume |
8 |
container_issue |
1 |
_version_ |
1778521825943224320 |