Winter energy balance and activity of female caribou on Coats Island, Northwest Territories: the relative importance of foraging and body reserves
Reduced availability of forage in winter is the dominant limiting factor for the isolated, predator-free caribou (Rangifer tarandus groenlandicus) population on Coats Island, Northwest Territories. Pregnant females in this population typically begin winter with large fat reserves but catabolize most...
Published in: | Canadian Journal of Zoology |
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Canadian Science Publishing
1993
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crcansciencepubl:10.1139/z93-167 2024-10-06T13:48:02+00:00 Winter energy balance and activity of female caribou on Coats Island, Northwest Territories: the relative importance of foraging and body reserves Adamczewski, J. Z. Hudson, R. J. Gates, C. C. 1993 http://dx.doi.org/10.1139/z93-167 http://www.nrcresearchpress.com/doi/pdf/10.1139/z93-167 en eng Canadian Science Publishing http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining Canadian Journal of Zoology volume 71, issue 6, page 1221-1229 ISSN 0008-4301 1480-3283 journal-article 1993 crcansciencepubl https://doi.org/10.1139/z93-167 2024-09-12T04:13:26Z Reduced availability of forage in winter is the dominant limiting factor for the isolated, predator-free caribou (Rangifer tarandus groenlandicus) population on Coats Island, Northwest Territories. Pregnant females in this population typically begin winter with large fat reserves but catabolize most of them by spring. We modelled net energy requirements of a pregnant female during two winters (1982 – 1983 and 1983 – 1984) to evaluate energy requirements for maintenance, activity, and pregnancy, and to estimate the contribution of body reserves in supplying these requirements. A secondary objective was to determine whether winter activity budgets were related to energy balance, quality of winter diets, or body condition. Estimated net energy requirements were lowest during midwinter (16 MJ/d for an average female) but increased rapidly toward spring. Maintenance was at all times the largest component of requirements, but gestation costs increased to 12 – 14% of total requirements by winter's end, and activity costs tended to increase from 3.8–4.0 MJ/d (23–25% of requirements) at the beginning of winter to 4.6–4.8 MJ/d (26 – 29% of costs) in late winter. Body reserves supplied an estimated 14.2% (1982 – 1983) and 19.2% (1983 – 1984) of overall winter requirements. The contribution from body reserves varied from 9 to 24% during different portions of the two winters and, in late winter 1982 – 1983, reserves may have been a crucial supplement at a time of decreased forage availability and rising energy costs. Caribou were least active in early winter, when they were fattest, and most active at winter's end when their energy needs were increasing. These patterns were not consistent with activity budgets of most mainland caribou, and winter activity budgets were not consistently related to either diet quality or body condition. Article in Journal/Newspaper Coats Island Northwest Territories Rangifer tarandus Canadian Science Publishing Coats Island ENVELOPE(-82.974,-82.974,62.620,62.620) Midwinter ENVELOPE(139.931,139.931,-66.690,-66.690) Northwest Territories Canadian Journal of Zoology 71 6 1221 1229 |
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Open Polar |
collection |
Canadian Science Publishing |
op_collection_id |
crcansciencepubl |
language |
English |
description |
Reduced availability of forage in winter is the dominant limiting factor for the isolated, predator-free caribou (Rangifer tarandus groenlandicus) population on Coats Island, Northwest Territories. Pregnant females in this population typically begin winter with large fat reserves but catabolize most of them by spring. We modelled net energy requirements of a pregnant female during two winters (1982 – 1983 and 1983 – 1984) to evaluate energy requirements for maintenance, activity, and pregnancy, and to estimate the contribution of body reserves in supplying these requirements. A secondary objective was to determine whether winter activity budgets were related to energy balance, quality of winter diets, or body condition. Estimated net energy requirements were lowest during midwinter (16 MJ/d for an average female) but increased rapidly toward spring. Maintenance was at all times the largest component of requirements, but gestation costs increased to 12 – 14% of total requirements by winter's end, and activity costs tended to increase from 3.8–4.0 MJ/d (23–25% of requirements) at the beginning of winter to 4.6–4.8 MJ/d (26 – 29% of costs) in late winter. Body reserves supplied an estimated 14.2% (1982 – 1983) and 19.2% (1983 – 1984) of overall winter requirements. The contribution from body reserves varied from 9 to 24% during different portions of the two winters and, in late winter 1982 – 1983, reserves may have been a crucial supplement at a time of decreased forage availability and rising energy costs. Caribou were least active in early winter, when they were fattest, and most active at winter's end when their energy needs were increasing. These patterns were not consistent with activity budgets of most mainland caribou, and winter activity budgets were not consistently related to either diet quality or body condition. |
format |
Article in Journal/Newspaper |
author |
Adamczewski, J. Z. Hudson, R. J. Gates, C. C. |
spellingShingle |
Adamczewski, J. Z. Hudson, R. J. Gates, C. C. Winter energy balance and activity of female caribou on Coats Island, Northwest Territories: the relative importance of foraging and body reserves |
author_facet |
Adamczewski, J. Z. Hudson, R. J. Gates, C. C. |
author_sort |
Adamczewski, J. Z. |
title |
Winter energy balance and activity of female caribou on Coats Island, Northwest Territories: the relative importance of foraging and body reserves |
title_short |
Winter energy balance and activity of female caribou on Coats Island, Northwest Territories: the relative importance of foraging and body reserves |
title_full |
Winter energy balance and activity of female caribou on Coats Island, Northwest Territories: the relative importance of foraging and body reserves |
title_fullStr |
Winter energy balance and activity of female caribou on Coats Island, Northwest Territories: the relative importance of foraging and body reserves |
title_full_unstemmed |
Winter energy balance and activity of female caribou on Coats Island, Northwest Territories: the relative importance of foraging and body reserves |
title_sort |
winter energy balance and activity of female caribou on coats island, northwest territories: the relative importance of foraging and body reserves |
publisher |
Canadian Science Publishing |
publishDate |
1993 |
url |
http://dx.doi.org/10.1139/z93-167 http://www.nrcresearchpress.com/doi/pdf/10.1139/z93-167 |
long_lat |
ENVELOPE(-82.974,-82.974,62.620,62.620) ENVELOPE(139.931,139.931,-66.690,-66.690) |
geographic |
Coats Island Midwinter Northwest Territories |
geographic_facet |
Coats Island Midwinter Northwest Territories |
genre |
Coats Island Northwest Territories Rangifer tarandus |
genre_facet |
Coats Island Northwest Territories Rangifer tarandus |
op_source |
Canadian Journal of Zoology volume 71, issue 6, page 1221-1229 ISSN 0008-4301 1480-3283 |
op_rights |
http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining |
op_doi |
https://doi.org/10.1139/z93-167 |
container_title |
Canadian Journal of Zoology |
container_volume |
71 |
container_issue |
6 |
container_start_page |
1221 |
op_container_end_page |
1229 |
_version_ |
1812176190293671936 |