Good Animals in Bad Places: Evaluating Landscape Attributes Associated with Elk Vulnerability to Wolf Predation

Scientific Disciplines
Biological Sciences - Terrestrial
Montana State University
Yellowstone national park
gray wolf
wolf reintroduction
wolf predation
environmental attributes
mortality risk
Volume 18, No. 1-4

Good animals in bad places: Evaluating landscape 
Attributes associated with elk vulnerability to 
Wolf predation
Shana L. Dunkley*, Department of Ecology, Montana State University, Bozeman, Montana 59717 
Robert A. Garrott, Department of Ecology, Montana State University, Bozeman, Montana 59717 
Jay J. Rotella, Department of Ecology, Montana State University, Bozeman, Montana 59717 
Megan D. Higgs, Department of Mathematical Sciences, Montana State University, Bozeman, 
Montana 59717 
Fred G. R. Watson, Division of Science and Environmental Policy, California State University 
Monterey Bay, Seaside, California 93955
Patrick J. White, Yellowstone Center for Resources, Yellowstone National Park, Wyoming 82190
Vulnerability of prey to predators is heavily influenced by their respective physical and 
behavioral characteristics; however their interactions with landscape, and climate, collectively 
termed “environmental vulnerability,” may also assume considerable importance.  Little is 
known about the impact of environmental vulnerability in large mammal systems, where 
post-encounter vulnerability may assume more importance than encounter probability. This 
study utilized 18 years of survival and mortality data for radio-collared elk (Cervus elaphus), 
in concert with abundance, distribution, and habitat use data prior to and following restoration 
of wolves (Canis lupus) to Yellowstone National Park to evaluate the relationship between 
environmental attributes and elk mortality.  We modeled the odds of mortality for 108 elk in 
1257 animal sample intervals from 1991-2009 across a range of environmental conditions 
and gradients of wolf predation risk to evaluate: 1) The relationship between landscape, 
habitat, and environmental attributes and elk vulnerability to wolf predation and 2) Changes 
in the attributes related to elk mortality before and after wolf colonization.  In the absence of 
wolf predation, mortality risk for elk was primarily associated with physical attributes of elk 
known to influence starvation mortality.  Following wolf reintroduction mortality risk was 
more strongly associated with characteristics of the landscape and climate within an animal’s 
home range. These environmental influences resulted in substantial changes in distribution 
and abundance of elk in the study system and suggests environmental heterogeneity may have 
an important influence on wolf and elk distributions and dynamics.