Risk effects in Elk (Cervus elaphus) : behavioral and nutritional responses to wolves and environmental conditions
Until recently, predators have been though to regulate prey primarily through direct predation, in ecosystems where top down effects have been shown to be important. However, experiments and recent empirical observations show that the costs of antipredator responses in individuals that successfully...
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Montana State University - Bozeman, College of Agriculture
2008
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ftmontanastateu:oai:scholarworks.montana.edu:1/1076 2023-05-15T15:51:00+02:00 Risk effects in Elk (Cervus elaphus) : behavioral and nutritional responses to wolves and environmental conditions Christianson, David Alan Chairperson, Graduate Committee: Scott Creel. 2008 application/pdf https://scholarworks.montana.edu/xmlui/handle/1/1076 en eng Montana State University - Bozeman, College of Agriculture https://scholarworks.montana.edu/xmlui/handle/1/1076 Copyright 2008 by David Alan Christianson Elk Animal behavior Wolves Predation (Biology) Feeds Dissertation 2008 ftmontanastateu 2022-06-06T07:28:58Z Until recently, predators have been though to regulate prey primarily through direct predation, in ecosystems where top down effects have been shown to be important. However, experiments and recent empirical observations show that the costs of antipredator responses in individuals that successfully avoid predation can exert equal or larger driving forces on population dynamics than the numerical effect of direct predation. Such a mechanism has not been explored in a large terrestrial vertebrate. I explored the antipredator responses of elk (Cervus elaphus) to wolves (Canis lupus) in the Upper Gallatin Canyon of southwest Montana, USA, December through May in the winters of 2003-2006. First I reviewed elk winter diet studies to understand what drives elk foraging behavior. Next I modeled the consequences of diet shifts in grazing and browsing on mass dynamics in wintering female elk. I also developed a new nutritional index, fecal chlorophyll, that I used primarily between winter and spring periods of nutrition as foraging constraints (and costs of antipredator response) would be quite different between these two periods. Specifically, I measured foraging behavior, diet selection, and nutrient balance in wintering elk and monitored daily predation risk as wolves moved naturally, in and out of four creek drainages that formed the primary winter range. Elk showed great sensitivity to fine-scale descriptions of wolf predation risk in nearly every response variable. In particular, adult female elk increased browsing on woody stems, sagebrush, and confers while adult males showed the opposition response and increased grazing on days when wolves were present in the same drainage. This work implies that predator may in fact play a large role in ecosystems including ecosystems where predators were deemed non-influential and bottom up effects important. Doctoral or Postdoctoral Thesis Canis lupus Montana State University (MSU): ScholarWorks Four Creek ENVELOPE(-127.137,-127.137,54.616,54.616) |
institution |
Open Polar |
collection |
Montana State University (MSU): ScholarWorks |
op_collection_id |
ftmontanastateu |
language |
English |
topic |
Elk Animal behavior Wolves Predation (Biology) Feeds |
spellingShingle |
Elk Animal behavior Wolves Predation (Biology) Feeds Christianson, David Alan Risk effects in Elk (Cervus elaphus) : behavioral and nutritional responses to wolves and environmental conditions |
topic_facet |
Elk Animal behavior Wolves Predation (Biology) Feeds |
description |
Until recently, predators have been though to regulate prey primarily through direct predation, in ecosystems where top down effects have been shown to be important. However, experiments and recent empirical observations show that the costs of antipredator responses in individuals that successfully avoid predation can exert equal or larger driving forces on population dynamics than the numerical effect of direct predation. Such a mechanism has not been explored in a large terrestrial vertebrate. I explored the antipredator responses of elk (Cervus elaphus) to wolves (Canis lupus) in the Upper Gallatin Canyon of southwest Montana, USA, December through May in the winters of 2003-2006. First I reviewed elk winter diet studies to understand what drives elk foraging behavior. Next I modeled the consequences of diet shifts in grazing and browsing on mass dynamics in wintering female elk. I also developed a new nutritional index, fecal chlorophyll, that I used primarily between winter and spring periods of nutrition as foraging constraints (and costs of antipredator response) would be quite different between these two periods. Specifically, I measured foraging behavior, diet selection, and nutrient balance in wintering elk and monitored daily predation risk as wolves moved naturally, in and out of four creek drainages that formed the primary winter range. Elk showed great sensitivity to fine-scale descriptions of wolf predation risk in nearly every response variable. In particular, adult female elk increased browsing on woody stems, sagebrush, and confers while adult males showed the opposition response and increased grazing on days when wolves were present in the same drainage. This work implies that predator may in fact play a large role in ecosystems including ecosystems where predators were deemed non-influential and bottom up effects important. |
author2 |
Chairperson, Graduate Committee: Scott Creel. |
format |
Doctoral or Postdoctoral Thesis |
author |
Christianson, David Alan |
author_facet |
Christianson, David Alan |
author_sort |
Christianson, David Alan |
title |
Risk effects in Elk (Cervus elaphus) : behavioral and nutritional responses to wolves and environmental conditions |
title_short |
Risk effects in Elk (Cervus elaphus) : behavioral and nutritional responses to wolves and environmental conditions |
title_full |
Risk effects in Elk (Cervus elaphus) : behavioral and nutritional responses to wolves and environmental conditions |
title_fullStr |
Risk effects in Elk (Cervus elaphus) : behavioral and nutritional responses to wolves and environmental conditions |
title_full_unstemmed |
Risk effects in Elk (Cervus elaphus) : behavioral and nutritional responses to wolves and environmental conditions |
title_sort |
risk effects in elk (cervus elaphus) : behavioral and nutritional responses to wolves and environmental conditions |
publisher |
Montana State University - Bozeman, College of Agriculture |
publishDate |
2008 |
url |
https://scholarworks.montana.edu/xmlui/handle/1/1076 |
long_lat |
ENVELOPE(-127.137,-127.137,54.616,54.616) |
geographic |
Four Creek |
geographic_facet |
Four Creek |
genre |
Canis lupus |
genre_facet |
Canis lupus |
op_relation |
https://scholarworks.montana.edu/xmlui/handle/1/1076 |
op_rights |
Copyright 2008 by David Alan Christianson |
_version_ |
1766386039466754048 |