As remarkable as Greater Yellowstone and Yellowstone National Park are during the rest of the year, the park in winter is a magical place: steam and boiling water erupt from natural cauldrons in the park’s ice-covered surface, snow-dusted bison exhale vaporous breaths as they lumber through drifts of white, foxes and coyotes paw and pounce in their search for prey in the deep snow, and gray wolves bay beneath the frozen moon. Yellowstone in winter also is a place of vulnerability.
Wildlife endure extremes of cold, wind, and the absence of ready food, their tracks through deep snow tell of tenacious struggles through the long winter. Park conditions in this most severe of seasons become critical to the mortality of wildlife and even to survival of park species.
No wonder the park is so popular in this magical, vulnerable season with those who have enjoyed its charms. It is often said among park staff who live in Yellowstone that winter is their favorite season. Many park visitors who try a winter trip to Yellowstone come back for more.
Deep snow, cold temperatures, and short days characterize winter in the Greater Yellowstone Ecosystem, conditions to which plants and animals are adapted. For example, conifers retain their needles through the winter, which extends their ability to photosynthesize. Aspens and cottonwoods contain chlorophyll in their bark, enabling them to photosynthesize before they produce leaves.
Morphological and Physical
Biochemical and Physiological
Greater Yellowstone’s soundscape is the aggregate of all the sounds within the park, including those inaudible to the human ear. Some sounds are critical for animals to locate a mate or food, or avoid predators. Other sounds, such as those produced by weather, water, and geothermal activity, may be a consequence rather than a driver of ecological processes. Human-caused sounds can mask the natural soundscape. The National Park Service goal is to protect or restore natural soundscapes where possible and minimize human-caused sounds while recognizing that they are generally more appropriate in and near developed areas. The quality of Greater Yellowstone’s soundscape therefore depends on where and how often non-natural sounds are present as well as their levels.
Human-caused sounds that mask the natural soundscape used by wildlife and enjoyed by park visitors are to some extent unavoidable in and near developed areas. However, the potential for frequent and pervasive high-decibel noise from oversnow vehicles has made the winter soundscape an issue of particular concern in Yellowstone. Management of the park’s winter soundscape is important because oversnow vehicles are allowed on roads in much of the park.
The list below includes academic publications, government publications, management documents that inform the decision-making process at Yellowstone. The Yellowstone Resources and Issues Handbook, updated annually, is the book our rangers use to answer many basic park questions.
Bjornlie, D.D. and R.A. Garrott. 2001. Effects of winter road grooming on bison in Yellowstone National Park. The Journal of Wildlife Management 65(3):560–572.
Borkowski, J.J., P.J. White, R. A. Garrott, T. Davis, A.R. Hardy, and D.J. Reinhart. 2006. Behavioral responses of bison and elk in Yellowstone to snowmobiles and snow coaches. Ecological Applications 16(5):1911–1925.
Borrie, W.T., W.A. Freimund, and M.A. Davenport. 2002. Winter visitors to Yellowstone National Park: Their value orientations and support for management actions. Human Ecology Review 9(2):41–48.
Bruggeman, J.E., R.A. Garrott, P.J. White, F.G.R. Watson, and R. Wallen. 2007. Covariates affecting spatial variability in bison travel behavior in Yellowstone National Park. Ecological Applications 17(5):1411–1423.
Cassirer, E.F., D.J. Freddy, and E.D. Ables. 1992. Elk responses to disturbance by cross-country skiers in Yellowstone National Park. Wildlife Society Bulletin 20(4):375–381.
Creel, S., J.E. Fox, J. Sands, B. Garrott, and R.O. Peterson. 2002. Snowmobile activity and glucocorticoid stress responses in wolves and elk. Conservation Biology 16(3):809–814.
Fortin, D. and M. Andruskiw. 2003. Behavioral response of free-ranging bison to human disturbance. Wildlife Society Bulletin 31(3):804–813.
Forrest, L. 1988. Field Guide to Tracking Animals in Snow. Harrisburg, PA: Stackpole Books.
Fuller, J.A., R.A. Garrott, and P.J. White. 2007. Emigration and density dependence in Yellowstone bison. Journal of Wildlife Management 71(6):1924–1933.
Halfpenny, J.C. and R.D. Ozanne. 1989. Winter: An Ecological Handbook. Boulder: Johnson Books.
Marchand, P.J. 1996. Life in the Cold. UNew England.
Thompson, H. 2004. Preserving natural soundscapes in the US national park system. In The George Wright Forum.
Olliff, T., K. Legg, and B. Kaeding. 1999. Effects of winter recreation on wildlife of the Greater Yellowstone area: A literature review and assessment. Greater Yellowstone Coordinating Committee, Greater Yellowstone Winter Wildlife Working Group.
Tanner, R.J., W.A. Freimund, W.T. Borrie, and R.N. Moisey. 2008. A meta-study of the values of visitors to four protected areas in the western United States. Leisure Sciences 30(5):377–390.
Yochim, M.J. 1999. The development of snowmobile policy in Yellowstone National Park. Yellowstone Science. 7(2).