The nitrogen window for arctic herbivores: plant phenology and protein gain of migratory caribou ( Rangifer tarandus)
Abstract Terrestrial plants are often limited by nitrogen (N) in arctic systems, but constraints of N supply on herbivores are typically considered secondary to those of energy. We tested the hypothesis that forage N is more limiting than energy for arctic caribou by collecting key forages (three sp...
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Online Access: | http://dx.doi.org/10.1002/ecs2.2073 https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Fecs2.2073 https://onlinelibrary.wiley.com/doi/pdf/10.1002/ecs2.2073 https://onlinelibrary.wiley.com/doi/full-xml/10.1002/ecs2.2073 https://onlinelibrary.wiley.com/doi/am-pdf/10.1002%2Fecs2.2073 https://esajournals.onlinelibrary.wiley.com/doi/pdf/10.1002/ecs2.2073 |
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crwiley:10.1002/ecs2.2073 2024-10-13T14:04:48+00:00 The nitrogen window for arctic herbivores: plant phenology and protein gain of migratory caribou ( Rangifer tarandus) Barboza, Perry S. Van Someren, Lindsay L. Gustine, David D. Bret‐Harte, M. Syndonia U.S. Geological Survey 2018 http://dx.doi.org/10.1002/ecs2.2073 https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Fecs2.2073 https://onlinelibrary.wiley.com/doi/pdf/10.1002/ecs2.2073 https://onlinelibrary.wiley.com/doi/full-xml/10.1002/ecs2.2073 https://onlinelibrary.wiley.com/doi/am-pdf/10.1002%2Fecs2.2073 https://esajournals.onlinelibrary.wiley.com/doi/pdf/10.1002/ecs2.2073 en eng Wiley http://creativecommons.org/licenses/by/3.0/ http://creativecommons.org/licenses/by/3.0/ Ecosphere volume 9, issue 1 ISSN 2150-8925 2150-8925 journal-article 2018 crwiley https://doi.org/10.1002/ecs2.2073 2024-09-17T04:49:47Z Abstract Terrestrial plants are often limited by nitrogen (N) in arctic systems, but constraints of N supply on herbivores are typically considered secondary to those of energy. We tested the hypothesis that forage N is more limiting than energy for arctic caribou by collecting key forages (three species of graminoids, three species of woody browse, and one genus of forb) over three summers in the migratory range of the Central Arctic Herd in Alaska from the Brooks Range to the Coastal Plain on the Arctic Ocean. We combined in vitro digestion and detergent extraction to measure fiber, digestible energy, and usable fractions of N in forages ( n = 771). Digestible energy content fell below the minimum threshold value of 9 kJ /g for one single forage group: graminoids, and only beyond 64–75 d from parturition (6 June), whereas all forages fell below the minimum threshold value for digestible N (1% of dry matter) before female caribou would have weaned their calves at 100 d from parturition. The window for digestible N was shortest for browse, which fell below 1% at 30–41 d from parturition, whereas digestible N contents of graminoids were adequate until 46–57 d from parturition. The low quality of browse as a source of N was also apparent from concentrations of available N (i.e., the N not bound to fiber) that were <1% at 72–80 d from parturition. The Coastal Plain may be favored by female caribou because available and digestible concentrations of N are not only greater than those on the Brooks Range, the window of usable N on the Coastal Plain extends the period of protein gain for females and their calves by 17 d. Conversely, inland areas with greater biomass and densities of digestible N than the Coastal Plain may be more favorable for large male caribou that begin gaining protein from spring to breed in autumn. Our study provides evidence that phenological windows for protein gain in caribou are both spatially and temporally dynamic and likely to affect the distribution and growth of the population. Article in Journal/Newspaper Arctic Arctic Ocean Brooks Range Rangifer tarandus Alaska Wiley Online Library Arctic Arctic Ocean Ecosphere 9 1 |
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Open Polar |
collection |
Wiley Online Library |
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crwiley |
language |
English |
description |
Abstract Terrestrial plants are often limited by nitrogen (N) in arctic systems, but constraints of N supply on herbivores are typically considered secondary to those of energy. We tested the hypothesis that forage N is more limiting than energy for arctic caribou by collecting key forages (three species of graminoids, three species of woody browse, and one genus of forb) over three summers in the migratory range of the Central Arctic Herd in Alaska from the Brooks Range to the Coastal Plain on the Arctic Ocean. We combined in vitro digestion and detergent extraction to measure fiber, digestible energy, and usable fractions of N in forages ( n = 771). Digestible energy content fell below the minimum threshold value of 9 kJ /g for one single forage group: graminoids, and only beyond 64–75 d from parturition (6 June), whereas all forages fell below the minimum threshold value for digestible N (1% of dry matter) before female caribou would have weaned their calves at 100 d from parturition. The window for digestible N was shortest for browse, which fell below 1% at 30–41 d from parturition, whereas digestible N contents of graminoids were adequate until 46–57 d from parturition. The low quality of browse as a source of N was also apparent from concentrations of available N (i.e., the N not bound to fiber) that were <1% at 72–80 d from parturition. The Coastal Plain may be favored by female caribou because available and digestible concentrations of N are not only greater than those on the Brooks Range, the window of usable N on the Coastal Plain extends the period of protein gain for females and their calves by 17 d. Conversely, inland areas with greater biomass and densities of digestible N than the Coastal Plain may be more favorable for large male caribou that begin gaining protein from spring to breed in autumn. Our study provides evidence that phenological windows for protein gain in caribou are both spatially and temporally dynamic and likely to affect the distribution and growth of the population. |
author2 |
U.S. Geological Survey |
format |
Article in Journal/Newspaper |
author |
Barboza, Perry S. Van Someren, Lindsay L. Gustine, David D. Bret‐Harte, M. Syndonia |
spellingShingle |
Barboza, Perry S. Van Someren, Lindsay L. Gustine, David D. Bret‐Harte, M. Syndonia The nitrogen window for arctic herbivores: plant phenology and protein gain of migratory caribou ( Rangifer tarandus) |
author_facet |
Barboza, Perry S. Van Someren, Lindsay L. Gustine, David D. Bret‐Harte, M. Syndonia |
author_sort |
Barboza, Perry S. |
title |
The nitrogen window for arctic herbivores: plant phenology and protein gain of migratory caribou ( Rangifer tarandus) |
title_short |
The nitrogen window for arctic herbivores: plant phenology and protein gain of migratory caribou ( Rangifer tarandus) |
title_full |
The nitrogen window for arctic herbivores: plant phenology and protein gain of migratory caribou ( Rangifer tarandus) |
title_fullStr |
The nitrogen window for arctic herbivores: plant phenology and protein gain of migratory caribou ( Rangifer tarandus) |
title_full_unstemmed |
The nitrogen window for arctic herbivores: plant phenology and protein gain of migratory caribou ( Rangifer tarandus) |
title_sort |
nitrogen window for arctic herbivores: plant phenology and protein gain of migratory caribou ( rangifer tarandus) |
publisher |
Wiley |
publishDate |
2018 |
url |
http://dx.doi.org/10.1002/ecs2.2073 https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Fecs2.2073 https://onlinelibrary.wiley.com/doi/pdf/10.1002/ecs2.2073 https://onlinelibrary.wiley.com/doi/full-xml/10.1002/ecs2.2073 https://onlinelibrary.wiley.com/doi/am-pdf/10.1002%2Fecs2.2073 https://esajournals.onlinelibrary.wiley.com/doi/pdf/10.1002/ecs2.2073 |
geographic |
Arctic Arctic Ocean |
geographic_facet |
Arctic Arctic Ocean |
genre |
Arctic Arctic Ocean Brooks Range Rangifer tarandus Alaska |
genre_facet |
Arctic Arctic Ocean Brooks Range Rangifer tarandus Alaska |
op_source |
Ecosphere volume 9, issue 1 ISSN 2150-8925 2150-8925 |
op_rights |
http://creativecommons.org/licenses/by/3.0/ http://creativecommons.org/licenses/by/3.0/ |
op_doi |
https://doi.org/10.1002/ecs2.2073 |
container_title |
Ecosphere |
container_volume |
9 |
container_issue |
1 |
_version_ |
1812810450121785344 |