Appendix I: Impacts of winter recreation on wildlife in Yellowstone National Park: A literature review and recommendations

Authors(s): J. W. Caslick

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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Location: Yellowstone National Park Wyoming

Abstract: Foreword ................................................................................................................................. A?5 Procedure and Products ........................................................................................................... A?5 Summary of Literature Review................................................................................................ A?7 Documented Impacts in Yellowstone ....................................................................................... A?8 Documented Impacts Elsewhere in Montana and Wyoming ................................................... A?9 Recommendations for Management ........................................................................................ A?9 1. Reduce snowmobile use in thermally influenced habitats ........................................... A?10 2. Discontinue speculation about harmful vs. beneficial impacts ................................... A?11 3. Initiate management experiments ................................................................................ A?11 4. Adopt standard terminology for classifying visitor-use impacts and management techniques .......................................................................... A?12 5. Consider non-visitor impacts ....................................................................................... A?12 6. Consider sacrifice areas ............................................................................................... A?13 7. Convene a panel of outside specialists ........................................................................ A?13 8. Prepare an EIS ............................................................................................................. A?13 Recommendations for Research ............................................................................................ A?14 1. Become pro-active in seeking funds and research proposals ...................................... A?14 2. Prioritize research support ........................................................................................... A?14 Appendix I ? New Citations on Winter Recreation Effects on Wildlife, J. and E. Caslick, 1997. 22 pp. ................................................... A?17 Appendix II ? Selected Literature Citations from Bennett, 1995, and New Citations from Caslick on Winter Recreation Effects on Wildlife, J. and E. Caslick, 1997. 74 pp. ................................................. A?41 Appendix III ? Matrix of Winter Recreation Effects on Wildlife, J. and E. Caslick, 1997. 25 pp. ................................................... A?111 Foreword Numerous studies have concluded that wildlife is a major component of the Yellowstone experience, and a major economic "draw" to the area. As increasing pressures for development of visitor facilities and new modes of transportation evolve, early consideration of their potential effects on wildlife (including individual animals, animal populations, and associated ecological processes) become ever more important, if wildlife resources are to continue to be a major feature of Yellowstone. The purpose of this report is to briefly summarize and evaluate the published research on winter recreation impacts on wildlife, particularly as they apply to Yellowstone, and to provide recommendations. This may have immediate application in decision-making during the trade-off processes that inevitably must occur when balancing resource conservation with visitor enjoyment. Procedure Starting in November 1996, I used "A Review of Potential Effects of Winter Recreation on Wildlife in Grand Teton and Yellowstone National Parks: A Bibliographic Data Base" by L. E. Bennett, 1995, as a starting point for the literature review. We obtained the electronic bibliographic component assembled with the ProCite bibliographic software program. I read the 139-page hard copy including the 465-entry bibliography, and deleted from our consideration 200 entries such as field guides that appeared to have little or no particular relevance to Yellowstone. Using this shortened bibliography, I read as many of the relevant publications as could be located in Yellowstone and made reprint requests to authors and publishers. I also searched the new ProCite Natural History Database in the Yellowstone Research Library, and other bibliographies on the topic kindly provided by others. The Montana State University Library had previously been searched by K. Legg of the Office of Planning and Compliance, YNP, who advised that a repeat of that search probably would not be productive. During my literature research, 211 new literature citations were discovered that seemed to have potential relevance to Yellowstone. Many of the most pertinent new literature sources that I found were in the M.S. and Ph.D. theses in the Yellowstone Research Library. All of these 211 new literature citations were listed in "New Citations on Winter Recreation Effects on Wildlife, J. and E. Caslick, 1997, 22 pp.," a copy of which is attached as Appendix 1. These new citations were then integrated with our revised list of Bennett (1995) to form "Selected Literature Citations from Bennett 1995 and New Citations from Caslick 1997 on Winter Recreation Effects on Wildlife, J. and E. Caslick, 1997, 74 pp.," a copy of which is attached as Appendix II. The new citations were also added to the revised ProCite database, now on file at YCR. I met with the Visitor Use Management (VUM) Planning Team's Wildlife Resource Impacts Work Group on December 17/96, January 31, and February 24/97, sought their suggestions, and provided members with copies of 10 pertinent articles, as well as a draft of the new citations listing. During the literature review and excerpting process, I attempted to retain the authors' interpretations by excerpting quotations; much can be lost otherwise. A summary of these findings in the literature was prepared as a matrix entitled "Matrix of Winter Recreation Effects on Wildlife, J. and E. Caslick, 1997, 25 pp.," a copy of which is attached as Appendix III. Rather than presenting a matrix chart with numbers that refer to a separate bibliography, it seemed much more immediately useful to excerpt the most pertinent information in the matrix and show the authors/dates, thus allowing the user a choice of searching out the complete article, or using my excerpt without having to chase out the reference. I found no documented impacts to mid-size carnivores. Although Yellowstone is believed to help support a viable population of wolverines, and lynx may have been resident over time, there is less evidence of historic or present fisher populations (Anon., National Park Service 1995:78). However, concern about the possibility of denning disturbance of wolverines by winter recreationists in high-altitude cirques was discussed by biologists at a VUM meeting in Bozeman this winter. Visitor impacts on coyotes have not been located in the literature, although in Yellowstone coyotes have long been observed to frequent plowed roads, snowmobile trails, ski trails, and other human trails, sometimes have been illegally fed, and apparently some coyotes have learned that they may be fed by humans. No research on this topic is listed in the 1995 YCR Investigators' Annual Report, although this continues to be a management concern. In an ongoing study of the effects of the l988 fires on coyotes, adult mortality was found to be "very low and primarily due to vehicles and mountain lions." Nine coyotes were reported killed by vehicles in the park in 1995 (Anon., National Park Service 1995). Although about 20 adult mountain lions inhabit Yellowstone's northern range, no impacts by recreationists other than by hunters outside the park have been documented (pers. comm. K. Murphy, Feb. 1997). I have not included effects on vegetation or soils in this report, because most winter recreationists in Yellowstone use established trails or roadways, with snowcover present. Time and the obscurity of some references precluded my review of all articles whose titles appeared to have some relevance to Yellowstone. I've included some of these in the matrix that may well be worthwhile to obtain and review. In general, I feel fairly comfortable about the extent of my review of this topic. More could be done, of course, and review of new literature on the topic should be ongoing, particularly the emerging bodies of literature on wildlife energetics and nutrition in winter, stresses induced by human activities (including roads), the importance of habitat corridors, stressed ecosystems, and the developing science of ecotourism. Summary of Literature Review Much of the literature on this topic dates from the 1970s, when snowmobiles were new on the winter scene. There was a flurry of related papers, particularly from the Midwestern states, where several snowmobile conferences were held at universities. Many of the publications appeared in conference proceedings, not in refereed journals, so many literature citations are anecdotal accounts rather than reports of well-designed research projects that have tested hypotheses and used "controls." Reports sometimes conflicted with previous findings, but there was general agreement that winter recreation, particularly snowmobiling, had great potential for negatively impacting wildlife and wildlife habitats (particularly vegetation). Even in these early conferences, snowmobile manufacturers were urged by wildlife biologists, at least, to design machines that were quieter and less-polluting. Snowmobile-polluted snow and its effects on wildlife, fish, and other aquatic organisms have not been investigated in Yellowstone, although published accounts elsewhere began at least 24 years ago (see 8 literature citations on "Polluted Snow" in this report). This seems to be another topic that should have been researched here long ago, particularly since we probably experience a higher intensity of snowmobile use than anywhere else, and since our fish and wildlife resources are so highly concentrated and of such unique public value. During the late 1970s and early 1980s, most of the publications on human impacts on wildlife dealt with impacts on nesting birds. Perhaps this is because such impacts are more readily evident and easier to quantify for birds than for mammals. Among birds, nesting shorebirds and waterfowl in refuges and parks were then the dominant topics. Later in the 1980s, literature began to be dominated by visitor effects on nesting bald eagles. Effects on ungulates began to be published as state game departments and the U.S. Forest Service became concerned. In 1985, Boyle and Samson published a benchmark bibliography of 536 references that identified 166 articles containing original data, and "reported that mechanized forms of recreation had the greatest impacts on wildlife, causing habitat disturbance, disrupting of animal behavior, noise pollution, and even direct mortality." (Purdy et al. 1987:6). The pace of publication slowed as some organizations imposed visitor-use restrictions, in a preventative mode, perhaps recognizing the difficulty and expense of definitive research. This is largely the situation today, although there is a slight increase of interest (largely academic) in quantifying nutritional and energetic stresses as they relate to ungulates and endangered species. The most recent publications of note deal with these latter topics, and with techniques for classifying, evaluating, and mitigating visitor use impacts. By far, the most comprehensive single reference on this topic is a new book by several specialists in this field, "Wildlife and Recreationists: Coexistence Through Management and Research," by R.L. Knight and K.J. Gutzwiller, eds. (1995), Island Press, Washington, D.C., 372 pp. During this project, I contacted the publisher for copyright permission and provided copies of pertinent chapters to members of the VUM Planning Team's Wildlife Resource Impacts Work Group. Twenty chapters with different authors address such topics as Factors that Influence Wildlife Responses to Recreationists, Physiological Responses of Wildlife to Disturbance, Recreational Disturbance and Wildlife Populations, and Indirect Effects of Recreationists on Wildlife. I highly recommend this book to anyone interested the current state of this topic. The published concern about direct and indirect effects of winter recreationists on wildlife has not diminished among wildlife researchers elsewhere. From the early and obvious effects of intentional snowmobile harassment on wintering concentrations of wildlife, particularly in the Midwestern and eastern U.S., interest soon (although slowly) turned to unintended effects of winter recreation on wildlife. As early as 1975, Severinghaus and Tullar of the New York State Conservation Department were using energy expenditure calculations to demonstrate that deer already pressed by winter conditions should not be further stressed by snowmobiles, and recommended that snowmobile trails should be at least 1/2 mile from winter concentrations of whitetailed deer. Winter harassment of deer by snowmobiles was reported as detrimental to their winter adaptations for energy conservation in New York and Minnesota (Moen 1976, 1978), and winter energetics considerations and calculations for ungulates have continued as highly important research topics reported in peer-reviewed journals and are continuing today. Some of this energetics research has very recently been conducted by others in Yellowstone (see DelGuidice et al. 1994, 1991, for bison and elk), and could be tied to research on the energy expenditures required for locomotion by ungulates (see Parker et al. 1984, for mule deer and elk), to result in meaningful implications for recreation impacts on wintering wildlife in Yellowstone. In fact, Parker et al. (1984) discussed management implications based on energy-costs of locomotion for mule deer and elk, when disturbed by winter recreationists, and they pointed out that "the additional energy drain on a wintering population on poor range may be an important factor in survival" (p. 486). I consider winter-energetics research to be the most meaningful direction for "pure" research to further clarify the extent to which winter recreationists are negatively affecting winter-stressed wildlife in Yellowstone. (See Recommendations for Research #2, below). Documented Impacts In Yellowstone As early as 1981, effects of winter recreationists on the physical environment of Yellowstone were reported to include air and snow pollution by snowmobile exhaust, litter, noise pollution, and limited damage to soils and plants in portions of the Madison, Firehole, and Gibbon river valleys (Aune 1981). My review of the literature leaves me with no doubt that winter recreation activities in Yellowstone have affected wildlife behavior and survival, including bison use of groomed snowmobile trails (Aune 1981), and groomed-trail effects on changes in bison movements, habitat use, distribution and calf survival (Meagher 1993); Yellowstone elk have been affected by cross-country skiers (Aune 1981; Cassirer et al. 1992), and in Yellowstone, snowmobiling or cross-country skiers have caused most trumpeter swans to fly (Shea 1979). Elsewhere in Montana and Wyoming Elsewhere in Montana and Wyoming, published literature documents that snowmobile use has impacted deer, elk and small mammals (Aasheim 1980), bald eagles (Shea 1975; Alt 1980; Harmata 1996), an avian scavenger guild including bald eagles and black-billed magpies (Skagen et al. 1991), elk (Aasheim 1980) and bighorn sheep (Berwick 1968). There is no apparent reason to expect that similar effects would not occur in Yellowstone, where winter conditions are generally more severe and the intensity of snowmobile usage is generally higher than elsewhere in Montana and Wyoming. Recommendations for Management Winter Weather Considerations Winters in Yellowstone are generally more severe than in any of the areas where recreational impacts on wildlife have been studied. This imposes an immediate constraint on applying the results of research conducted elsewhere; Yellowstone winters likely impose greater stresses on wildlife, even before visitor-induced stresses are added. For example, snowmobile activity in the Midwestern states has been shown to result in white-tailed deer movements away from trails. The energy cost of such movement at Midwestern snowdepths and temperatures are likely to be much less than for a similar movement under Yellowstone winter conditions. This movement must also be considered in the contexts of energy replacement costs and the quality of the habitat to which deer must move-must they now move more than previously to meet their energy requirements? Proximity to and Overlap of Road Systems, Critical Winter Habitats (thermally-influenced) and Recreation Activities (road, trails, developments). In Yellowstone, as elsewhere, there is a general shift of wildlife to lower-elevation habitats during winter. These habitats often are the riparian habitats in which the road system has been constructed. Since snowmobiling in Yellowstone is presently restricted to these established roadways, there is an immediate conflict in land uses. We have built our roads and developed areas in important (and perhaps key) wildlife wintering habitats, thereby reducing wildlife carrying capacity of the park. Winter uses and groomed roads are new environmental factors in these traditional wintering grounds, and we have yet to learn if and how some wildlife species, guilds, or populations will be affected in the long term. Some immediate effects are apparent, including displacement of individual animals and small groups, and associated energy expenditures by wildlife that result from recreationist activities and the related support and maintenance activities of the park and park concessioners. There can be little doubt that continued human activity and additional commercial developments in these riparian areas will continue to degrade and diminish winter wildlife habitats, through depletion of resources previously available to wintering wildlife. This has been the pattern of wildlife population declines world-wide; there is no rationale for expecting results to be different here. Yellowstone now has wildlife in relative abundance because of a relatively low rate of human exploitation of habitats, but the clock is ticking and the exploitation rate is rapidly increasing. The challenge for park managers is to apply the brakes now to slow the exploitation rate. Enforcement of park regulations alone will likely not suffice. Managers must make aggressive use of new techniques that promise to assist resource conservation efforts while concurrently accommodating visitor use. The science of ecotourism shows promise in this regard and park managers should explore its literature, learn how its principles are being applied in park management elsewhere (Anderson 1993; Blangley & Wood 1993; deGroot 1983; Wallace 1993), and stay tuned for further developments. The management emphasis here must be on conservation, education, then visitor use, in that order of priority, if the wildlife values of this park are to be retained in the long-term. 1. Reduce Snowmobiling Impacts in Thermally-Influenced Habitats In regard to wildlife in Yellowstone, I conclude from my literature review that the most pressing VUM issue is snowmobiling-not snowmobiling in general, but snowmobiling in and near thermally-affected wildlife habitats that are known to be unique and of critical value to wildlife in winter. This value to Yellowstone wildlife is not conjecture; it has been widely recognized and published about for many years, particularly in regard to elk (USDI/NPS 1990), bison (Meagher 1970), bald eagles (Alt 1980; Swenson 1986, USDI/NPS 1990, 1995), and trumpeter swans (Shea 1979; USDI/NPS 1990). The Matrix of Winter Recreation Effects on Wildlife and Selected Literature Citations. . . attached as Appendices III and II support this view. From my literature review, I conclude that there is now ample documentation to administratively close these thermally-influenced winter habitats, prohibiting winter use by private and commercial snowmachines, skiers, snowshoers, and hikers. To increase protection of these thermally-influenced wildlife habitats in winter and to interrupt the existing network of groomed trails now known to be used by Yellowstone elk and moose (USDI/NPS 1990) and bison (Aune 1981; Meagher 1993), I therefore recommend that private and commercial snowmachine use be permitted in the park only as follows: (1) Mammoth to Indian Creek Campground (2) West Entrance to 7-mile Bridge (3) South Entrance to Lewis Lake Campground (4) East Entrance to Sylvan Lake (or Sylvan Pass). To further reduce impacts on wildlife, over-snow administrative travel on other park roads should be restricted to the middle hours of daylight (i.e., 10 a.m. to 4 p.m.) to avoid wildlife disturbance during their early morning and evening feeding periods. During winter, processes that influence energy intake, rather than energy expenditure, have a much greater influence on the energy balances of ungulates (Hobbs 1989). 2. Discontinue the "Harmful vs. Beneficial" Dichotomy. I recommend that VUM planners and managers in Yellowstone discontinue speculation about whether particular impacts are harmful or beneficial to wildlife. Where management's objective is to maintain natural processes and minimize the effects of humans, such value judgments are inappropriate and unproductive. Rather, the appropriate challenges seem to be detection of impacts, quantification thereof, timely decisions on priorities for mitigation activities, and implementation of those activities. 3. Initiate Visitor Use Management Trials and Monitor the Results. From years of experience in wildlife research and management, I am aware of the tendency to call for more research and thereby postpone important decisions until research results are available. Certainly more research on the topic of this report would be useful, and recommendations for research are given in a later section of this report. But there is a recent development in methodology for tackling complex management issues that does not seem to be in use in Yellowstone. This is the approach called for by Dr. N. Christensen when he delivered the Leopold Lecture at Yellowstone's First Biennial Scientific Conference in 1991. He said, "ignorance will not provide a reprieve from managing" and that through viewing management plans as "working hypotheses that can be tested over time," the challenges can be overcome (Anon. 1992) (emphasis added). This idea had been previously suggested by MacNab (1983) and most recently by Knight and Gutzwiller (1995), who suggested that serial management experiments can be used to assess cause and effect relationships - such as visitor use impacts - using temporal and spatial controls, randomized designs, covariates, and adequate replication. Note that these are management experiments not intended to replace long-term research, but to initiate action programs that may be helpful, while awaiting research results. In Yellowstone, we don't need to prove that specific human activities are impacting wildlife before we initiate management measures. Where there are indications that impacts may be occurring, managers could undertake experimental management measures to reduce/minimize/eliminate these effects, while carefully documenting the results of the experimental management program. This documentation would provide a basis for making decisions about visitor use management needs and possibly elucidate priorities for research. 4. Adopt Standardized Terminology for Classification of Impacts and Impact-Mitigation Techniques. Visitor use management in Yellowstone should be based on the recognition that there is no such thing as the non-consumptive use of wildlife or other natural resources. Every use exacts a toll. This has been a published view for at least 20 years (Wilkes 1977; Weedin 1981). VUM then becomes a series of decisions about: (1) what is the toll? (2) is the toll acceptable? (3) if not, how can the toll be reduced? To classify impacts on wildlife, I recommend the scheme developed by Purdy et al. (1987) for the National Wildlife Refuges; these impacts are: Direct Mortality Indirect Mortality Lowered Productivity Reduced Use of Refuge (Park for YNP) Reduced Use of Preferred Habitat Aberrant Behavior/Stress The classifications could as well serve as standards for evaluating visitor impacts on wildlife, and as standards evaluating the effectiveness of VUM measures in Yellowstone. The suggested measures of controlling visitor-related impacts on refuges (Visitor Education, Zoning, Restrictions on Activities, Law Enforcement, and various combinations of these measures) are all applicable here and could as well serve as a classification scheme for YNP mitigation efforts. 5. Consider Non-Visitor Impacts The VUM plan should address impacts to wildlife that result from tour groups, scientists, educational activities (NPS, Yellowstone Institute, school groups, concessioner activities and NPS administrative activities) (see White and Bratton 1980). Mitigation techniques - initially evaluated as management trials - might include both temporal and spatial components. For example, during the period between official close of the park for the winter season and opening for the summer season, the park could restrict administrative travel on the previously groomed snowmobile routes to that required for official emergency travel only. Whenever possible, restrict even this emergency use to the mid-daylight hours (i.e., 10 a.m. to 4 p.m.) to avoid disruption of the major feeding times for wildlife, during these critical weeks in wildlife survival. 6. Consider Sacrifice Areas In defining VUM Potential Opportunity Areas, there seems to be an underlying assumption that it is desirable to distribute recreation throughout the greater Yellowstone area (p. 1, para. 3, Feb. 1996 draft). I recommend that this basic assumption be reconsidered to include the possibility that small sacrifice areas and large administrative closures may be ecologically preferable. For example, in Yellowstone, it may be preferable to dedicate a small area of low-quality wildlife habitat to heavy-use snowmobiling if, in so doing, a large thermal area of high-quality wildlife habitat is thereby protected. 7. Convene a Panel of Outside Specialists Convene a panel of outside specialists on winter recreation effects on wildlife, specialists on human dimensions in wildlife management, and specialists in conflict resolution in resource management, to address the topic "Management of Winter Recreation Impacts on Wildlife in Yellowstone." Provide participants with copies of this report and other pertinent information, including NPS policy, prior to the meeting. Charge them with making recommendations for both immediate and long-term visitor management, and related short-term and long-term research projects and priorities. I can provide names of some potential participants. I recognize that suggestion of a panel of outside experts may strike fear in the hearts of some administrators, but recommendations may be accepted or rejected, and traditional public hearings in gateway communities cannot be expected to provide expertise or consensus. In fact, Dr. Kellert of Yale University, a specialist in public attitudes and the human dimensions of resource management, has published his view that public hearings are confrontational procedures that tend to harden positions and foster polarization. Like lake trout control, visitor use management here is a complex issue requiring input from specialists. 8. Prepare an EIS Based upon the published effects of winter recreation on wildlife in Yellowstone that are documented here, and possibly including other air and water quality concerns in Yellowstone, promptly initiate preparation of an Environmental Impact Statement (EIS) on Winter Visitor Use in Yellowstone. In the EIS, include alternatives of "no snowmobiling" as well as alternatives for additional spatial and temporal restrictions on over-snow travel, as outlined above. Include consideration of alternative modes of transport for winter visitor enjoyment of park resources. Suspend further improvement and development of facilities to accommodate winter visitors (including Old Faithful Snowlodge), pending outcome of the NEPA process.

Keywords: bibliography, Greater Yellowstone Ecosystem, Yellowstone National Park, Grand Teton National Park, wildlife, management, human activity, animal, mammal, population, mortality, habitat, carnivore, Mustelidae, wolverine, Gulo gulo, Lynx, Lynx Canadensis, Lynx lynx, Bobcat, Felis rufus, Felidae, feline, fisher, Martes pennanti, den, denning, coyote, Canidae, canine, Canis latrans, mountain lion, cougar, puma, Felis concolor, Fish, Pisces, Aves, bird, nest, nesting, waterfowl, water bird, Anatidae, Eagle, Bald eagle, Haliaeetus leucocephalus, Raptor, Ungulate, Cervidae, Deer, Whitetailed deer, Odocoileus virginianus, Bison, Bison bison, Elk, Wapiti, Cervus elaphus, mule deer, Odocoileus hemionus, distribution, swan, trumpeter swan, Olor buccinator, magpie, black-billed magpie, Pica pica, sheep, bighorn sheep, Ovis canadensis