An application of upscaled optimal foraging theory using hidden Markov modelling: year-round behavioural variation in a large arctic herbivore
Abstract Background In highly seasonal environments, animals face critical decisions regarding time allocation, diet optimisation, and habitat use. In the Arctic, the short summers are crucial for replenishing body reserves, while low food availability and increased energetic demands characterise th...
Published in: | Movement Ecology |
---|---|
Main Authors: | , , , , , , , , , |
Other Authors: | , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
Springer Science and Business Media LLC
2020
|
Subjects: | |
Online Access: | http://dx.doi.org/10.1186/s40462-020-00213-x https://link.springer.com/content/pdf/10.1186/s40462-020-00213-x.pdf https://link.springer.com/article/10.1186/s40462-020-00213-x/fulltext.html |
id |
crspringernat:10.1186/s40462-020-00213-x |
---|---|
record_format |
openpolar |
spelling |
crspringernat:10.1186/s40462-020-00213-x 2023-05-15T14:51:19+02:00 An application of upscaled optimal foraging theory using hidden Markov modelling: year-round behavioural variation in a large arctic herbivore Beumer, Larissa T. Pohle, Jennifer Schmidt, Niels M. Chimienti, Marianna Desforges, Jean-Pierre Hansen, Lars H. Langrock, Roland Pedersen, Stine Højlund Stelvig, Mikkel van Beest, Floris M. 15. Juni Fonden Miljøstyrelsen AUFF Starting Grant 2020 http://dx.doi.org/10.1186/s40462-020-00213-x https://link.springer.com/content/pdf/10.1186/s40462-020-00213-x.pdf https://link.springer.com/article/10.1186/s40462-020-00213-x/fulltext.html en eng Springer Science and Business Media LLC https://creativecommons.org/licenses/by/4.0 https://creativecommons.org/licenses/by/4.0 CC-BY Movement Ecology volume 8, issue 1 ISSN 2051-3933 Ecology, Evolution, Behavior and Systematics journal-article 2020 crspringernat https://doi.org/10.1186/s40462-020-00213-x 2022-01-04T14:49:21Z Abstract Background In highly seasonal environments, animals face critical decisions regarding time allocation, diet optimisation, and habitat use. In the Arctic, the short summers are crucial for replenishing body reserves, while low food availability and increased energetic demands characterise the long winters (9–10 months). Under such extreme seasonal variability, even small deviations from optimal time allocation can markedly impact individuals’ condition, reproductive success and survival. We investigated which environmental conditions influenced daily, seasonal, and interannual variation in time allocation in high-arctic muskoxen ( Ovibos moschatus ) and evaluated whether results support qualitative predictions derived from upscaled optimal foraging theory. Methods Using hidden Markov models (HMMs), we inferred behavioural states (foraging, resting, relocating) from hourly positions of GPS-collared females tracked in northeast Greenland (28 muskox-years). To relate behavioural variation to environmental conditions, we considered a wide range of spatially and/or temporally explicit covariates in the HMMs. Results While we found little interannual variation, daily and seasonal time allocation varied markedly. Scheduling of daily activities was distinct throughout the year except for the period of continuous daylight. During summer, muskoxen spent about 69% of time foraging and 19% resting, without environmental constraints on foraging activity. During winter, time spent foraging decreased to 45%, whereas about 43% of time was spent resting, mediated by longer resting bouts than during summer. Conclusions Our results clearly indicate that female muskoxen follow an energy intake maximisation strategy during the arctic summer. During winter, our results were not easily reconcilable with just one dominant foraging strategy. The overall reduction in activity likely reflects higher time requirements for rumination in response to the reduction of forage quality (supporting an energy intake maximisation strategy). However, deep snow and low temperatures were apparent constraints to winter foraging, hence also suggesting attempts to conserve energy (net energy maximisation strategy). Our approach provides new insights into the year-round behavioural strategies of the largest Arctic herbivore and outlines a practical example of how to approximate qualitative predictions of upscaled optimal foraging theory using multi-year GPS tracking data. Article in Journal/Newspaper Arctic Greenland muskox ovibos moschatus Springer Nature (via Crossref) Arctic Greenland Movement Ecology 8 1 |
institution |
Open Polar |
collection |
Springer Nature (via Crossref) |
op_collection_id |
crspringernat |
language |
English |
topic |
Ecology, Evolution, Behavior and Systematics |
spellingShingle |
Ecology, Evolution, Behavior and Systematics Beumer, Larissa T. Pohle, Jennifer Schmidt, Niels M. Chimienti, Marianna Desforges, Jean-Pierre Hansen, Lars H. Langrock, Roland Pedersen, Stine Højlund Stelvig, Mikkel van Beest, Floris M. An application of upscaled optimal foraging theory using hidden Markov modelling: year-round behavioural variation in a large arctic herbivore |
topic_facet |
Ecology, Evolution, Behavior and Systematics |
description |
Abstract Background In highly seasonal environments, animals face critical decisions regarding time allocation, diet optimisation, and habitat use. In the Arctic, the short summers are crucial for replenishing body reserves, while low food availability and increased energetic demands characterise the long winters (9–10 months). Under such extreme seasonal variability, even small deviations from optimal time allocation can markedly impact individuals’ condition, reproductive success and survival. We investigated which environmental conditions influenced daily, seasonal, and interannual variation in time allocation in high-arctic muskoxen ( Ovibos moschatus ) and evaluated whether results support qualitative predictions derived from upscaled optimal foraging theory. Methods Using hidden Markov models (HMMs), we inferred behavioural states (foraging, resting, relocating) from hourly positions of GPS-collared females tracked in northeast Greenland (28 muskox-years). To relate behavioural variation to environmental conditions, we considered a wide range of spatially and/or temporally explicit covariates in the HMMs. Results While we found little interannual variation, daily and seasonal time allocation varied markedly. Scheduling of daily activities was distinct throughout the year except for the period of continuous daylight. During summer, muskoxen spent about 69% of time foraging and 19% resting, without environmental constraints on foraging activity. During winter, time spent foraging decreased to 45%, whereas about 43% of time was spent resting, mediated by longer resting bouts than during summer. Conclusions Our results clearly indicate that female muskoxen follow an energy intake maximisation strategy during the arctic summer. During winter, our results were not easily reconcilable with just one dominant foraging strategy. The overall reduction in activity likely reflects higher time requirements for rumination in response to the reduction of forage quality (supporting an energy intake maximisation strategy). However, deep snow and low temperatures were apparent constraints to winter foraging, hence also suggesting attempts to conserve energy (net energy maximisation strategy). Our approach provides new insights into the year-round behavioural strategies of the largest Arctic herbivore and outlines a practical example of how to approximate qualitative predictions of upscaled optimal foraging theory using multi-year GPS tracking data. |
author2 |
15. Juni Fonden Miljøstyrelsen AUFF Starting Grant |
format |
Article in Journal/Newspaper |
author |
Beumer, Larissa T. Pohle, Jennifer Schmidt, Niels M. Chimienti, Marianna Desforges, Jean-Pierre Hansen, Lars H. Langrock, Roland Pedersen, Stine Højlund Stelvig, Mikkel van Beest, Floris M. |
author_facet |
Beumer, Larissa T. Pohle, Jennifer Schmidt, Niels M. Chimienti, Marianna Desforges, Jean-Pierre Hansen, Lars H. Langrock, Roland Pedersen, Stine Højlund Stelvig, Mikkel van Beest, Floris M. |
author_sort |
Beumer, Larissa T. |
title |
An application of upscaled optimal foraging theory using hidden Markov modelling: year-round behavioural variation in a large arctic herbivore |
title_short |
An application of upscaled optimal foraging theory using hidden Markov modelling: year-round behavioural variation in a large arctic herbivore |
title_full |
An application of upscaled optimal foraging theory using hidden Markov modelling: year-round behavioural variation in a large arctic herbivore |
title_fullStr |
An application of upscaled optimal foraging theory using hidden Markov modelling: year-round behavioural variation in a large arctic herbivore |
title_full_unstemmed |
An application of upscaled optimal foraging theory using hidden Markov modelling: year-round behavioural variation in a large arctic herbivore |
title_sort |
application of upscaled optimal foraging theory using hidden markov modelling: year-round behavioural variation in a large arctic herbivore |
publisher |
Springer Science and Business Media LLC |
publishDate |
2020 |
url |
http://dx.doi.org/10.1186/s40462-020-00213-x https://link.springer.com/content/pdf/10.1186/s40462-020-00213-x.pdf https://link.springer.com/article/10.1186/s40462-020-00213-x/fulltext.html |
geographic |
Arctic Greenland |
geographic_facet |
Arctic Greenland |
genre |
Arctic Greenland muskox ovibos moschatus |
genre_facet |
Arctic Greenland muskox ovibos moschatus |
op_source |
Movement Ecology volume 8, issue 1 ISSN 2051-3933 |
op_rights |
https://creativecommons.org/licenses/by/4.0 https://creativecommons.org/licenses/by/4.0 |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.1186/s40462-020-00213-x |
container_title |
Movement Ecology |
container_volume |
8 |
container_issue |
1 |
_version_ |
1766322358349463552 |