Sustaining big game populations in the face of increasing land use and environmental change is a top priority for agencies, industry, and the public. WEST has the experience and expertise needed to provide clients with science-based solutions to big game management and conservation challenges.
WEST’s scientists have substantial expertise designing, conducting, and analyzing studies for a wide range of big game species, including mountain sheep, mountain goat, mule deer, white-tailed deer, pronghorn, elk, moose, grizzly bear, polar bear, and cougar. We have accomplished and published dozens of abundance and occupancy analyses using a variety of methods, including mark and recapture, distance sampling, direct counts, photo sampling, infrared sensors, and aerial surveys. WEST specializes in delineating critical habitats (e.g., migratory routes, stopovers, winter range) from Global Positioning System data and impact assessments that evaluate behavioral responses to habitat change and human disturbance.
All routes are not created equal: An ungulate’s choice of migration route can influence its survival
Hall Sawyer, Chad W. LeBeau, T. L. McDonald, W. Zu, and A. D. Middleton
Long‐term effects of energy development on winter distribution and residency of pronghorn in the Greater Yellowstone Ecosystem
Hall Sawyer, J. P. Beckman, R. G. Seidler, and J. Berger
Summer Habitat Use of Female Mule Deer in Oregon
C. A. Eckrich, P. K. Coe, D. A. Clark, R. M. Nielsen, John Lombardi, S. C. Gregory, M. H. Hedrick, B. K. Johnson, and D. H. Johnson
Conserving transboundary wildlife migrations: recent insights from Greater Yellowstone Ecosystem
A. D. Middleton, Hall Sawyer, J. A. Merkle, M. J. Kauffman, E. K. Cole, S. R. Dewey, J. A. Gude, D. D. Gustine, D. E. McWhirter, K. M. Proffitt, and P. J. White
The seasonal migrations of ungulates are increasingly threatened by various forms of anthropogenic disturbance, including roads, fences, and other infrastructure. While roadway impacts of two-lane highways to mule deer can largely be mitigated with underpasses and continuous fencing, similar mitigation may not be effective for pronghorn or other ungulate species that are reluctant to move through confined areas.
The Wyoming Department of Transportation installed six underpasses and two overpasses along 20 kilometers of US Highway 191. Species-specific preferences were evaluated by documenting the number of migratory mule deer and pronghorn that used adjacent overpasses and underpasses for three years following construction.
WEST staff, including Dr. Hall Sawyer documented 40,251 mule deer and 19,290 pronghorn that migrated across the highway. Of those 79% of mule deer moved under the highway whereas 93% of pronghorn moved over the highway.
Our results highlight that species-specific preferences are an important consideration when mitigating roadway impacts with wildlife crossing structures. Overpass and underpass construction reduced wildlife-vehicle collisions by approximately 81%.