SPATIAL BEHAVIOR, FORAGING, AND POPULATION DYNAMICS OF A SUBARCTIC UNGULATE
The concept of density-dependence is foundational to our understanding of the ecology and management of large herbivores. As the abundance of large herbivores increases, competition for high-quality resources increases and animals select for lower-quality foods potentially resulting in reduced vital...
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ftunivmontana:oai:scholarworks.umt.edu:etd-13083 2023-07-16T03:57:11+02:00 SPATIAL BEHAVIOR, FORAGING, AND POPULATION DYNAMICS OF A SUBARCTIC UNGULATE Ehlers, Elizabeth (Libby) Parr Williamson 2022-01-01T08:00:00Z application/pdf https://scholarworks.umt.edu/etd/11965 https://scholarworks.umt.edu/context/etd/article/13083/viewcontent/Ehlers_umt_0136D_10737.pdf unknown University of Montana https://scholarworks.umt.edu/etd/11965 https://scholarworks.umt.edu/context/etd/article/13083/viewcontent/Ehlers_umt_0136D_10737.pdf Graduate Student Theses, Dissertations, & Professional Papers behavior demography density dependence migratory caribou nutrition summer diet dissertation 2022 ftunivmontana 2023-06-27T23:53:39Z The concept of density-dependence is foundational to our understanding of the ecology and management of large herbivores. As the abundance of large herbivores increases, competition for high-quality resources increases and animals select for lower-quality foods potentially resulting in reduced vital rates that cause declines in population growth. What remains unclear is how foraging at finer scales, like the ‘bite’, translates to demography. This is difficult because it’s challenging to scale bite-level foraging to population-levels. I test the fine-scale foraging mechanisms of density dependence in a large subarctic herbivore, Barrenground caribou (Rangifer tarandus granti). The nutritional landscape for arctic herbivores is changing faster than anywhere else on Earth from global climate change, so understanding population-level consequences of foraging behavior is paramount. The Fortymile Caribou Herd (FCH) is a barrenground population ranging across Alaska and Yukon, Canada that, unlike most, has recently increased in abundance and distribution. First, I used GPS-video-camera collars to understand fine-scale behavior and diet patterns. This revealed i) a pronounced tradeoff in summer foraging between lichens and shrubs and, ii) the costs of insect harassment on eating. Second, I tested how foraging choices were influenced by spatiotemporal factors in summer. I found spatial tradeoffs in behavioral and foraging choices. As spatial densities of the FCH increased, the probability of eating shrubs increased as cover (%) for Salix spp. shrubs increased. Conversely, the probability of caribou eating lichen declined with increasing spatial densities. Caribou choice for preferred summer foods also increased with the availability of such foods revealing foraging functional responses. Finally, I linked bottom-up drivers of nutritional ecology to juvenile survival to test predictions of density dependence. I found biologically important effects of bottom-up forage-related factors on maternal condition, neonate birth ... Doctoral or Postdoctoral Thesis Arctic Climate change Rangifer tarandus Subarctic Alaska Yukon University of Montana: ScholarWorks Arctic Canada Yukon |
institution |
Open Polar |
collection |
University of Montana: ScholarWorks |
op_collection_id |
ftunivmontana |
language |
unknown |
topic |
behavior demography density dependence migratory caribou nutrition summer diet |
spellingShingle |
behavior demography density dependence migratory caribou nutrition summer diet Ehlers, Elizabeth (Libby) Parr Williamson SPATIAL BEHAVIOR, FORAGING, AND POPULATION DYNAMICS OF A SUBARCTIC UNGULATE |
topic_facet |
behavior demography density dependence migratory caribou nutrition summer diet |
description |
The concept of density-dependence is foundational to our understanding of the ecology and management of large herbivores. As the abundance of large herbivores increases, competition for high-quality resources increases and animals select for lower-quality foods potentially resulting in reduced vital rates that cause declines in population growth. What remains unclear is how foraging at finer scales, like the ‘bite’, translates to demography. This is difficult because it’s challenging to scale bite-level foraging to population-levels. I test the fine-scale foraging mechanisms of density dependence in a large subarctic herbivore, Barrenground caribou (Rangifer tarandus granti). The nutritional landscape for arctic herbivores is changing faster than anywhere else on Earth from global climate change, so understanding population-level consequences of foraging behavior is paramount. The Fortymile Caribou Herd (FCH) is a barrenground population ranging across Alaska and Yukon, Canada that, unlike most, has recently increased in abundance and distribution. First, I used GPS-video-camera collars to understand fine-scale behavior and diet patterns. This revealed i) a pronounced tradeoff in summer foraging between lichens and shrubs and, ii) the costs of insect harassment on eating. Second, I tested how foraging choices were influenced by spatiotemporal factors in summer. I found spatial tradeoffs in behavioral and foraging choices. As spatial densities of the FCH increased, the probability of eating shrubs increased as cover (%) for Salix spp. shrubs increased. Conversely, the probability of caribou eating lichen declined with increasing spatial densities. Caribou choice for preferred summer foods also increased with the availability of such foods revealing foraging functional responses. Finally, I linked bottom-up drivers of nutritional ecology to juvenile survival to test predictions of density dependence. I found biologically important effects of bottom-up forage-related factors on maternal condition, neonate birth ... |
format |
Doctoral or Postdoctoral Thesis |
author |
Ehlers, Elizabeth (Libby) Parr Williamson |
author_facet |
Ehlers, Elizabeth (Libby) Parr Williamson |
author_sort |
Ehlers, Elizabeth (Libby) Parr Williamson |
title |
SPATIAL BEHAVIOR, FORAGING, AND POPULATION DYNAMICS OF A SUBARCTIC UNGULATE |
title_short |
SPATIAL BEHAVIOR, FORAGING, AND POPULATION DYNAMICS OF A SUBARCTIC UNGULATE |
title_full |
SPATIAL BEHAVIOR, FORAGING, AND POPULATION DYNAMICS OF A SUBARCTIC UNGULATE |
title_fullStr |
SPATIAL BEHAVIOR, FORAGING, AND POPULATION DYNAMICS OF A SUBARCTIC UNGULATE |
title_full_unstemmed |
SPATIAL BEHAVIOR, FORAGING, AND POPULATION DYNAMICS OF A SUBARCTIC UNGULATE |
title_sort |
spatial behavior, foraging, and population dynamics of a subarctic ungulate |
publisher |
University of Montana |
publishDate |
2022 |
url |
https://scholarworks.umt.edu/etd/11965 https://scholarworks.umt.edu/context/etd/article/13083/viewcontent/Ehlers_umt_0136D_10737.pdf |
geographic |
Arctic Canada Yukon |
geographic_facet |
Arctic Canada Yukon |
genre |
Arctic Climate change Rangifer tarandus Subarctic Alaska Yukon |
genre_facet |
Arctic Climate change Rangifer tarandus Subarctic Alaska Yukon |
op_source |
Graduate Student Theses, Dissertations, & Professional Papers |
op_relation |
https://scholarworks.umt.edu/etd/11965 https://scholarworks.umt.edu/context/etd/article/13083/viewcontent/Ehlers_umt_0136D_10737.pdf |
_version_ |
1771543699712376832 |