Effects of winter recreation on gray wolves

Authors(s): D. Reinhart

Publication: Effects of winter recreation on wildlife of the Greater Yellowstone Area: a literature review and assessment. Report to the Greater Yellowstone Coordinating Committee. Yellowstone National Park, Wyoming.

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Publication Date: 0000-00-00

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Abstract: POPULATION STATUS AND TREND Gray wolves (Canis lupus) were once distributed throughout North America and were native to the Yellowstone area (Bangs and Fritts 1996). In the conterminous United States, they were extirpated to 3 percent of their historical range (Fuller et al. 1992). In the Greater Yellowstone Area (GYA), wolves were eliminated by the mid-1930s as a result of systematic predator control (Weaver 1978). Following the approval of the 1994 environmental impact statement on the reintroduction of gray wolves into the Yellowstone and central Idaho ecosystems, wolves were reintroduced to these areas in 1995 and 1996 (USFWS 1994). Although wolves are classified as ?endangered? in Montana, Idaho, and Wyoming under the Endangered Species Act of 1973 (USC 1531, 1982 amend.), they were reclassified as ?experimental/non-essential populations? in the Yellowstone and central Idaho ecosystems before they were reintroduced to allow more flexibility in managing the species. This designation allows government agencies more options for relocating or removing individual wolves preying on livestock (USFWS 1994). In 1995, 14 wolves were reintroduced into Yellowstone National Park using three ?soft release? pen sites; 17 additional wolves were reintroduced to the park in 1996, and four pen sites were used (Phillips and Smith 1997). In January 1999, there were approximately 116 wolves in at least seven packs within the GYA (Bangs et al. In Press). LIFE HISTORY Wolves are highly social and hierarchical, and they live in family groups called packs. Packs consist of the dominant or ?alpha? breeding pair, their recent litter of pups, and other adult and subadult individuals (Mech 1970, Tilt et al. 1987). During early spring (mid-March to early April), wolf packs excavate a den and rear a litter of pups. Average estimated birth date for wolf pups in the Yellowstone area in 1995 and 1996 was April 24 (Phillips and Smith 1997); pups are nursed six to eight weeks. At one to two years of age, a young wolf leaves the pack and tries to form its own pack. Wolves depend upon ungulates for food. In the Yellowstone area, the primary prey for wolves is elk (87%); other prey includes moose, deer, antelope, and bison (Phillips and Smith 1997). Wolves prey on ungulates throughout the year (Tilt et al. 1987), and use ungulate carcasses (elk and bison) during early spring prior to denning. The peak period of availability of carcasses occurs about mid-April (Green et al. 1997; D. Smith, Yellowstone National Park, personal communication). HABITAT Wolves are not habitat specific and use much of the landscape within their pack?s established territory (Mladenoff et al. 1995), however, snow depth and condition can influence wolf movements in the winter (Mech 1970, Paquet et al. In Press). Winter foraging occurs primarily on ungulate winter range. The ungulate winter range is also the key spring habitat for wolves as most winter-killed carcasses are found here. HUMAN ACTIVITIES Winter recreation has the potential to affect gray wolf movements and habitat use during the period of winter foraging and early spring denning. In the GYA, winter foraging typically occurs on the following ungulate winter ranges: the Yellowstone northern range (Mack and Singer 1992), the North Fork of the Shoshone River, the Jackson Hole basin, the Clarks Fork River (Boyce and Galliard 1992), and the areas that are geothermally influenced within Yellowstone National Park (Green et al. 1997). Some information exists on specific effects of winter recreation on gray wolves. Most information, however, is available from data on the effects of other human activities. Paquet et al. (In Press) found that winter movements of wolves in Canadian parks were influenced by human activities. Winter activities that compact snow cover, such as snowmobiling, cross-country skiing, and maintenance of winter roads, provided feasible travel routes for wolves into areas that were usually inaccessible because of deep snow (more than 15.5?19.5 inches). The consequences of this are that there may be modifications to wolf/prey interactions and habitat use as well as differences in landscape movements between groups of prey (Paquet et al. In Press). Studies of snowmobile use and wolf movements in Voyagers National Park (NPS 1996) have shown that wolves tended to avoid areas of snowmobile activity in restricted-use areas. The studies also showed that repeated avoidance or displacement could result in permanent displacement, an impact to an animal?s winter energy budget, and/or a conditioning of the animal to avoid certain areas. While the study did not prove that winter recreational use harmed wolves, it suggested that the National Park Service should close important wolf foraging areas to winter use until a better understanding of wolf?snowmobile interactions could be determined. Other studies have documented similar responses by wolves in the avoidance of roads. In Kenai National Wildlife Refuge, radiocollared gray wolves avoided year-round access roads open to public use and were attracted to roads that were closed or were managed for limited human use. Wolves used low-use roads as travel corridors (Thurber et al. 1994). Wolf avoidance of settled areas and public roads in this study area was more a result of behavioral avoidance rather than direct mortality of animals. In Jasper National Park, wolves avoided traveled roads and were negatively affected by disturbance at den sites (Carbyn 1974). In Yellowstone National Park, wolves use areas near groomed snowmobile roads because there are ungulates wintering in the vicinity. On one occasion in 1997, wolves initially used an elk kill along a groomed snowmobile road and then left it when humans were present (D. Smith, Yellowstone National Park, personal communication). Developments in Canada were shown to negatively affect wolves in Banff, Yoho, and Kootenay national parks. In Banff National Park, the town of Banff partially blocks natural wolf movement, denying access to prime habitat east of town (Purves et al. 1992). POTENTIAL EFFECTS Winter recreation has the potential to affect gray wolves during winter foraging and denning periods. Potential wolf/human conflicts could occur in winter foraging habitats, along snowmobile and ski trails, or near developments. The literature shows that wolves both used and avoided roads and trails designated for winter use. Although wolves use snowmobile trails for travel and foraging, they avoid roads, trails, and facilities if humans are present. The ecological significance of altering natural movement and foraging patterns is not fully known. Human activity during late winter/early spring could also displace wolves during the sensitive denning period. Gray wolves in the GYA are particularly affected by human use of the following Potential Opportunity Areas: (1) Destination areas. Wolves may avoid habitats near winter developments when they occur on or near important ungulate winter ranges and when the developments remain open during spring denning periods (early to mid-April). This is especially critical when developments occur in or near high-quality winter and spring habitats that may include geothermally influenced winter range, low-elevation winter range, and other areas where winter-killed carcasses are found. (2) Primary transportation routes and (3) scenic driving routes. Primary roads may affect wolf populations by fragmenting pack movement and causing direct mortalities. Five wolves were killed by vehicles in Yellowstone National Park between 1995 and 1997 (Gunther et al. 1998). (4) Groomed motorized routes. Conflicts could occur when routes groomed for snowmobiles bisect habitats used by wolves in the winter, affecting wolf movements and foraging patterns. Moreover, grooming of roads and trails may affect ungulate movements (Meagher 1993), and this may influence wolf movements as well (Paquet et al. In Press). Areas of particular concern are ungulate concentration sites where winter-killed carcasses are available. These include both geothermally influenced and low elevation winter ranges. (6) Backcountry motorized areas. Wolf activity could be affected in ungroomed areas used by snowmobiles. Although areas of ungroomed snowmobile use typically occur at high elevations where wolves do not occupy winter habitats, there is potential for conflicts between wolves and recreationists if winter snowmobiling occurs on low-elevation or geothermally influenced ungulate winter range. Impacts would also occur if wolves were deliberately chased by recreationists on snowmobiles. MANAGEMENT GUIDELINES * New winter recreational developments should not be built near ungulate winter ranges or where they would impede wolf movements between high-quality habitats. Moreover, existing destination areas should be closed by April 1 to prevent the displacement of wolves during critical denning periods. * By definition, year-round routes will remain open whether winter recreation occurs or not. Wildlife managers should immediately remove road-killed animals from roadsides to prevent foraging wolves from being hit by vehicles. * New groomed motorized routes should be located in areas that are not classified as ungulate winter range or important wolf habitat. Grooming and use of snowmobile roads and trails should end between March 15 and April 1, allowing wolves to use spring denning sites without harassment. Human use of geothermally influenced winter ranges in the Firehole, Gibbon, and Norris areas of Yellowstone National Park should be managed during winter in a manner that allows wolves to forage; human use may cause displacement from these high quality habitats. * Dispersed motorized use should not occur on or near ungulate winter range or on spring range after wolf denning begins, usually between March 15 and April 1. LITERATURE CITED Bangs, E. B., and S. H. Fritts. 1996. Reintroducing the gray wolf to central Idaho and Yellowstone National Park. Wildlife Society Bulletin 24(3):402?413. ???, ???, J. Fontaine, D. Smith, K. Murphy, C. Mack, and C. Niemeyer. In Press. Status in wolf restoration in Montana, Idaho and Wyoming. Wildlife Society Bulletin. Boyce, M. S., and J. M. Galliard. 1992. Wolves of Yellowstone, Jackson Hole, and the North Fork of the Shoshone River: simulating ungulating consequences of wolf recovery. Pages 43?70 in Wolves for Yellowstone? A report to the United States Congress, Volume 4, research and analysis. National Park Service, Yellowstone National Park, Wyoming, USA. Carbyn, L. N. 1974. Wolf population fluctuations in Jasper National Park, Alberta, Canada. Biological Conservation 6(2):94? 101. Fuller, T. K., W. E. Berg, G. L. Raddle, M. S. Lenarx, and G. B. Joselyn. 1992. A history and current estimate of wolf distribution and numbers in Minnesota. Wildlife Society Bulletin 20:42?55. Green, G. I., D. J. Mattson, and J. M. Peek. 1997. Spring feeding on ungulate carcasses by grizzly bears in Yellowstone National Park. Journal of Wildlife Management 61(4):1040?1055. Gunther, K. A., M. J. Biel, and H. L. Robison. 1998. Factors influencing the frequency of roadkilled wildlife in Yellowstone National Park. Pages 32?42 in G. L. Evink, P. Garrett, D. Zeigler, and J. Berry, editors. Proceedings of the International Conference on Wildlife Ecology and Transportation. Florida Department of Transportation, FL-ER-69?98. Fort Meyers, Florida, USA. Mack, J. A., and F. J. Singer. 1992. Predicted effects of wolf predation on northern range elk, mule deer, and moose using POP-II models. Pages 3?42 in Wolves for Yellowstone? A report to the United States Congress, Volume 4, research and analysis. National Park Service, Yellowstone National Park, Wyoming, USA. Meagher, M. 1993. Winter recreation-induced changes in bison numbers and distribution in Yellowstone National Park. Unpublished data. National Park Service, Yellowstone National Park, Wyoming, USA. Mech, L. D. 1970. The wolf: the ecology and behavior of an endangered species. Natural History Press. Garden City, New York, USA. Mladenoff, D. J., T. A. Sickley, R. G. Haight, and A. P. Wydeven. 1995. A regional landscape analysis and prediction of favorable gray wolf habitat in the northern Great Lakes region. Conservation Biology 9(2):279?294. NPS (National Park Service). 1996. Restricted winter use report, Voyageurs National Park (1992?1996). Voyageurs National Park, International Falls, Minnesota, USA. Paquet, P. C., D. Poll, S. Alexander, C. McTavish, and C. Callaghan. In Press. Influences of snow conditions on movements of wolves in Canadian mountain parks. Journal of Wildlife Management. Phillips, M. K., and D. W. Smith. 1997. Yellowstone wolf project: biennial report 1995?1996. National Park Service, Yellowstone National Park, Wyoming, USA. Purves, H. D., C. A. White, and P. C. Paquet. 1992. Wolf and grizzly bear habitat use and displacement by human use in Banff, Yoho, and Kootenay national parks: a preliminary analysis. Heritage Resources Conservation. Canadian Park Service, Banff, Alberta, Canada. Thurber, J. M., R. O. Peterson, T. D. Drummer, and S. A. Thomasa. 1994. Gray wolf response to refuge boundaries and roads in Alaska. Wildlife Society Bulletin 22(1):61?68. Tilt, W., R. Norris, and A. S. Eno. 1987. Wolf recovery in the northern Rocky Mountains. National Audubon Society and National Fish and Wildlife Foundation. Washington, D.C., USA. USFWS (U.S. Fish and Wildlife Service). 1994. The reintroduction of gray wolves to Yellowstone National Park and central Idaho. Final Environmental Impact Statement. Helena, Montana, USA. Weaver, J. 1978. The Wolves of Yellowstone. Natural Resources Report, No. 14. National Park Service, Washington, D.C., USA. PREPARED BY: Dan Reinhart, Management Biologist, National Park Service, Yellowstone National Park, Wyoming, USA. REVIEWED BY: Douglas Smith, Ph.D., Wolf Project Leader, National Park Service, Yellowstone National Park, Wyoming, USA. Kerry Murphy, Ph.D., Wildlife Biologist, National Park Service, Yellowstone National Park, Wyoming, USA. Kerry Gunther, Bear Biologist, National Park Service, Yellowstone National Park, Wyoming, USA.

Keywords: animal, mammal, human activity, habitat, behavior, migration, population, mortality, Greater Yellowstone Ecosystem, Yellowstone National Park, Jackson Hole, Teton County, Predation, Canidae, Canis lupus, Wolf, Wildlife, Management, Hunting, Carnivore, Food, Foraging, Breeding, Den, Denning, Ungulate, Elk, Cervidae, Cervus elaphus, Wapiti, Moose, Alces alces, Antelope, Antilocapra Americana, Bison, Bison bison, deer, bibliography