Are you using a screen reader? Click here to view the navigation links for this site as a bulleted list.

Partner logos: BLM, FWS, FS, NPS, University of Montana Logo
Connecting federal employees, scientists, educators, and the public with their wilderness heritage
Text size: A | A | A  [Print]

Threats to Wilderness From Overuse

The Wilderness Act of 1964 gave land managers a difficult and challenging mandate. Wilderness areas are to be kept in a wild and natural state--relatively free of human control--while, at the same time, providing for their use and enjoyment.

The first survey on outdoor recreation was done in 1960. Since then, outdoor recreation has been increasing dramatically, driven primarily by the growth of the U.S. population by over 100 million in just over 40 years. Participation in canoeing and kayaking, for example, grew from 2.6 million in 1960 to 15 million in the early 1980s to 28 million by 2000; Participation in day hiking and backpacking has increased by 194% and 182%, respectively, since the early 1980s[1]. Wilderness visitation has also increased, almost sixfold according to agency estimates, between 1965 and 1994[2].

Changes in Wilderness Visitation

In addition to increases in outdoor recreation participation and wilderness visitation, the typical wilderness visit is also changing. Wilderness visitor groups are getting smaller, typically ranging from 2-5 people, lengths of stay are getting shorter, with day use being the most common type of wilderness visit, and many people are now choosing to visit wilderness areas closer to their home or in their home state[3][4]. This map shows wildlands and their proximity to cities. Half of all wilderness areas are within a day's drive of America's 30 largest cities.

Map of wilderness and public land within a days drive of some of America's largest cities.
Map key: Red circles 150-mile radius around America's largest cities
Map key: Light green Wilderness areas within 150 miles of one or more of America's largest cities
Map key: Dark green Wilderness areas not within 150 miles of any of America's largest cities
Map key: Light brown Non-wilderness BLM, FWS, FS, and NPS lands within 150 miles of one or more of America's largest cities
Map key: Dark brown Non-wilderness BLM, FWS, FS, and NPS lands not within 150 miles of any of America's largest cities

Biophysical Impacts from Visitors

Research has shown that recreation can impact both biophysical and social aspects of wilderness. Common biophysical impacts include trampling, campfires and wood collection, tree damage, wildlife disturbance and trash. Overall, Leave No Trace education plays an important role in helping visitors understand how they can minimize their biophysical impacts when recreating in wilderness.


Perhaps the most common type of biophysical impact is trampling, caused by the footsteps of hikers and pack stock, which can damage or kill plants, compact soil, and increase erosion. Trampling research shows that small amounts of use generally cause substantial impact, while additional use increases impacts much less. Site durability also plays an important role in how well areas resist impacts.

Research plots showing the results of trampling on forbs and grasses.
The research plots above illustrate the effects of trampling on forbs and grasses. The pictures in the left column show untrampled forbs (top) and grasses (bottom). After 250 passes, forbs (top right) show considerable damage and the bare ground beneath is visible, while grasses (bottom right) show less damage and no evidence of bare ground. Studies like these show that grasses are more resistant to trampling than forbs and are a better choice for campsites.
A study of campsites in Wyoming's Popo Agie Wilderness exemplifies both of these statements[5]. In this study, researchers found that camping for one night in a previously unused forested area eliminating 60% of the vegetation, while four nights eliminated 80%. On neighboring meadow campsites, however, four nights of camping had no effect on the vegetation during the first year of use. Degradation started to occur during the second year with vegetation loss of less than 20% and no further loss occurred during the third year.

Research also shows that recovery rates for highly trampled areas are variable but are almost always slower than rates of deterioration. For example, impacts of trampling are still visible 30 years after experiments were conducted in alpine vegetation in Glacier National Park[6], while in contrast, evidence of camping in closed riparian campsites at Delaware Water Gap disappeared after only six years[7].

Not surprisingly, larger groups of people create larger impacts[8] and pack stock generally create more trampling impacts than hikers[9]. Of particular interest in grazing areas is trampling damage done to wet meadows by pack stock. In many cases, pack stock are prohibited from grazing during wet seasons to minimize trampling impacts.

Although trampling, to some extent, is an unavoidable and tolerated consequence of the Wilderness Act's mandate to provide for the use and enjoyment of wilderness by all Americans, campsite and trail impacts have increased greatly over the past several decades, primarily due to the creation of new campsites and trails rather than the recovery of existing ones[10]. For example, the number of campsites increased by 53% in the Selway-Bitterroot Wilderness between 1977 and 1989, 84% in the Lee Metcalf Wilderness between 1975 and 1990, and 123% in the Eagle Cap Wilderness between 1972 and 1988[11].

As such, common strategies to minimize trampling impacts include concentrating use on existing trails and campsites, discouraging shortcutting and creation of social trails, requiring camping on designated campsites in areas that receive extremely high use, distributing low levels of use in extremely durable areas, rocky or grassy areas that resist impacts, for example, or discouraging use of certain areas when they are wet and more prone to erosion or relocating trails to prevent erosion.

A collage showing tree damage at campsites and trash left by wilderness visitors.
Unlike this cut tree, managers recommend collecting only wood that is generally smaller than 3 inches in diameter for campfires. Trash, like this pile in the Leatherwood Wilderness negatively impacts wildlife and other visitors.


Other types of biophysical impacts include campfires. Campfires sterilize soil, making it critically important to confine fires to existing fire rings or, in some cases, to prohibit or discourage campfires in areas where firewood is minimal, such as in white bark pine forests at high elevations in the Sierra Nevadas.

Tree Damage

Wood collection for campfires depletes woody debris that serves to nurture new vegetation growth in and around campsites. For example, research in Oregon wildernesses showed an average 40% reduction in woody material 30 to 45 feet from the center of campsites[12]. To minimize wood collection impacts, managers discourage live tree cutting, recommend leaving large downed woody debris alone and burning only downed wood that can be broken by hand. Tying pack stock can also damage or kill live trees, and hitch rails, or corrals, are sometimes found in wilderness and served to both keep stock away from trees and concentrate their trampling impacts into small areas.

Wildlife Disturbance

Wilderness visitors can also directly disturb wildlife, either intentionally, through hunting, trapping, fishing or fish stocking, for example, or unintentionally. Trash, including food, and habitat modification, such as firewood collection, can affect small mammals and bird populations by changing food sources and shelter options[13]. Off-season use of wilderness can be particularly taxing for wildlife. Several studies, for example, have documented elk disturbance in winter by cross-country skiers[14][15] As such, some wilderness areas are closed--partially or entirely--during nesting, breeding or critical feeding times. Part of Florida's Cedar Keys Wilderness, for example, is closed to public entry from March 1 through June 30 to protect colonial nesting birds.


Unfortunately, wilderness visitors often leave trash and other human waste in wilderness. Although it is a generally accepted practice to bury human waste in catholes, some heavily used areas, such as Mount Adams in the Mount Adams Wilderness, now highly recommend or require the use of portable personal waste disposal systems such as Wag Bags. There is little excuse for leaving trash in wilderness, however, since Leave No Trace recommends that visitors who pack-it-in also pack-it-out.

Crowding on a mountaintop.
Crowding, exemplified by the five groups of people (circled in red) seen recreating in close proximity, is well-documented on Old Rag Mountain in the Shenandoah Wilderness.

Social Impacts from Visitors

Biophysical impacts to wilderness are sometimes more visible than social impacts, however social impacts can pose significant threats to the quality of visitor experiences. Social impacts include crowding, loss of solitude, and conflict.

Crowding and Loss of Solitude

Crowding and loss of solitude are important impacts to the social aspects of wilderness that can occur from recreation. Although visitor experiences are complex, encounter monitoring is often used as a measurement technique for understanding social impacts since encounters, both on trails and at campsites, are an important determinant of experiencing solitude in wilderness. For example, 68% of hikers surveyed at trailheads in the Shenandoah Wilderness indicated that seeing a few or no other groups contributed to a sense of solitude[16]. Survey respondents in the Alpine Lakes Wilderness and Three Sisters Wilderness indicated that lack of encounters, particularly at campsites or rest areas, added greatly to the sense of having a real wilderness experience[17]. This study also suggests that the effects of increasing encounters are more pronounced on moderate-use trails than on high-use trails. Indeed, when faced with crowding, users desiring high levels of solitude are often displaced from high-use locations. For example, 13% of respondents surveyed in 19 Oregon and Washington wildernesses could identify at least one place within a wilderness to which they would not return, with crowding being the most cited reason[18].

Research suggests, however, that the majority of wilderness visitors are adaptable[3][19]. In studies of high-use locations in Oregon and Washington wilderness areas, researchers found that although wilderness visitors do care about how many other people they encounter, "they learn; they plan; they adjust their expectations; they cope; they rationalize; they view things in relative terms—rather than in absolutes—they say 'this place provides more solitude...' rather than 'this place provides no solitude'; they make trade-offs. They adapt"[3 p. 129]. As such, management actions that limit access, such as the institution of use limits, are not widely supported when proposed for the purposes of maintaining quality visitor experiences rather than to mitigate biophysical impacts[3][18].


There is also recognition that visitor density is not the only factor affecting the social aspects of wilderness. Different user groups often have contrasting views on wilderness values, and types of encounters, not just numbers, can lead to conflicts. Much of the research on conflict in wilderness has centered on conflicting recreational uses, such as conflicts between hikers and stock users, private and commercial rafters, hunters and non-hunters, solitary and social outdoors-people, or visitors with and without dogs. In many cases, conflict between user groups is asymmetrical, or one sided. For example, while only 4% of John Muir Wilderness stock users disliked their encounters with hikers on a specific trip, over one-third (36%) of hikers who met horses disliked the encounters[20]. Conflict occurs due to differences in four ways to describe wilderness visitors[21]:

Visitor Differences Definition Example
Activity Style The various personal meanings assigned to and the intensity with which visitors participate in selected activities. An angler who places high importance on tying flies and luring wild cutthroat trout to a barbless hook will likely experience conflict with spinning or bait anglers sharing the same resource[22].
Resource Specificity The significance attached to using a specific place or resource for a given recreational experience. Mountain bikers in Montana's Rattlesnake National Recreation Area were more dependent upon the place than hikers because they reported fewer substitutes for the kind of biking they liked to do there than hikers reported[23].
Mode of Experience The varying expectations of how the natural environment is perceived or the focus of a given recreational experience. Mountain bikers at the Rattlesnake National Recreation Area were found to be most focused on the activity itself, while the hikers who were feeling conflict were more focused upon their social group or the environment[23].
Lifestyle Tolerance The tendency to accept or reject lifestyles different from one's own and believe in stereotypes. Private rafters on Idaho's Salmon River may experience conflict when encountering commercial rafters if they know or believe that commercial rafters: are the dominant user on that river; tend to have much higher annual household incomes; are generally novice river floaters; have high expectations for nature but attach low value to solitude; tend to come from distant large urban centers; and do not have to compete in a lottery system like private floaters to obtain a permit[24].


  1. Cordell, H. K., Beltz, C. J., Green, G. T., Mou, S. Leeworthy, V. R., Wiley, P. C., et al. (2004). Outdoor Recreation for 21st Century America. State College, PA: Venture Publishing.
  2. Cole, D. N. (1996b). Wilderness Recreation Use Trends, 1965 Through 1994. Res. Pap. INT-RP-488. Ogden, UT: USDA For. Serv., Intermountain Research Station 15p.
  3. Cole, D. N. & Hall, T. E. (2008). The "Adaptable Human" Phenomenon: Implications for Recreation Management in High-Use Wilderness. In: Weber, Samantha, Harmon, David eds. Rethinking Protected Areas in a Changing World. Proceedings of the 2007 George Wright Society Conference: 126-131. Retrieved on October 19, 2009.
  4. Roggenbuck, J. W. & Watson, A. E. (1989). Wilderness Recreation Use: The Current Situation. In: Watson, A. E., compiler. Outdoor Recreation Benchmark 1988: Proceedings of the National Outdoor Recreation Forum; 1988, January 13-14; Tampa, FL. Gen. Tech. Rep. SE-52. Asheville, NC: USDA For. Serv., Southeastern Forest Exper. Stn 346-356pp.
  5. Cole, D. N. & Monz, C. A . (2003). Impacts of Camping on Vegetation: Response and Recovery Following Acute and Chronic Disturbance. Environmental Management, 32(6), 693-705.
  6. Hartley, E. A. (1999). Visitor Impact at Logan Pass, Glacier National Park: A 30-year Education Study. In: Harmon, E., ed. On the Frontiers of Conservation: Proceedings of the 10th George Wright Society Biennial Conference on Research and Resource Management in Parks and Public Land; March 22-26, 1999; Asheville, NC. Hancock, MI: The George Wright Society, pp. 297-305.
  7. Marion, J. & Cole, D. N. (1996). Spatial and Temporal Variation in Soil and Education Impacts on Campsites. Ecological Applications, 6(2), 520-530.
  8. Dawson, C. P. & Hendee, J. C. (2009). Wilderness Management: Stewardship and Protection of Resources and Values (4th ed.). Golden, CO: Fulcrum Publishing.
  9. Cole, D. N. & Spildie, D. R. (1998). Hiker, Horse, and Llama Trampling Effects on native vegetation in Montana, USA. Journal of Environmental Management, 53(1), 61-71.
  10. Cole, D. N. (1996a). Wilderness Recreation in the United States--Trends in Use, Users, and Impacts. International Journal of Wilderness, 2(3), 14-18. Retrieved on September 23, 2009.
  11. Cole, D. N. (1993). Campsites in Three Western Wildernesses: Proliferation and Changes in Ccondition Over 12 to 16 Years. Res. Pap. INT-463. Ogden, UT: USDA For. Serv., Intermountain Research Station 15p. Retrieved on September 23, 2009.
  12. Hall, T. E. & Farrell, T. A. (2001). Fuelwood Depletion at Wilderness Campsites: Extent and Potential Ecological Significance. Environmental Conservation, 28(3), 241-247.
  13. Cole, D. N. & Landres, P. (1995). Indirect Effects of Recreationists on Wildlife. In: Knight, R. L, Gutzwiller, K. J. eds. Wildlife and Recreationists: Coexistence Through Management and Research. Washington, D.C.: Island Press, pp. 183-202. Retrieved on October 19, 1009.
  14. Cassirer, E. F., Freddy, D. J. & Ables, E. D. (1992). Elk Responses to Disturbance by Cross-Country Skiers in Yellowstone National Park. Wildlife Society Bulletin, 20(2), 375-381.
  15. Ferguson, M. A. D. & Keith, L. B. (1982). Influence of Nordic Skiing on Distribution of Moose and Elk in Elk Island National Park, Alberta. Canadian Field Naturalist, 96, 69-78.
  16. Hall, T. E. (2001). Hikers' Perspectives on Solitude and Wilderness. International Journal of Wilderness, 7(2), 20-24. Retrieved on September 24, 2009.
  17. Cole, D. N. & Hall, T. E. (2009). Perceived Effects of Setting Attributes on Visitor Experiences in Wilderness: Variation with Situational Context and Visitor Characteristics. Environmental Management 44, 24-26. Retrieved on October 19, 2009.
  18. Hall, T. E. & Cole, D. N. (2007). Changes in the Motivations, Perceptions, and Behaviors of Recreation Users: Displacement and Coping in Wilderness. Res. Pap. RMRS-RP-63. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station. 37 p. Retrieved on October 19, 2009.
  19. Dustin, D., & L. McAvoy. (1982). The Decline and Fall of Quality Recreation Opportunities and Environments? Environmental Ethics, 4(1), 49–57.
  20. Watson, A. E., Niccolucci, M. J. & Williams, D. R. (1994). The Nature of Conflict Between Hikers and Recreational Stock Users in the John Muir Wilderness. Journal of Leisure Research 26(4), 372-385. Retrieved on October 28, 2009.
  21. Jacob, G. R., & Schreyer, R. (1980). Conflict in Outdoor Recreation: A Theoretical Perspective. Journal of Leisure Research 12, 368–380.
  22. Watson, A. E. (2001). Goal Interference and Social Value Differences: Understanding Wilderness Conflicts and Implications for Managing Social Density. In: Freimund, W. A., Cole, D. N. comps. Visitor Use Density and Wilderness Experience. 2001 June 1-3; Missoula, MT U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station: Ogden, UT Proc RMRS-P-20: 62-66. Retrieved on October 27, 2009.
  23. Watson, A. E., Williams, D.R., & Daigle, J.J. (1991). Sources of Conflict Between Hikers and Mountain Bike Riders in the Rattlesnake NRA. Journal of Park and Recreation Administration, 9, 59–71.
  24. Hunger, D. H., Christensen, N. A., & Becker, K. G. (1999). Commercial and Private Boat Use on the Salmon River in the Frank Church-River of No Return Wilderness, United States. International Journal of Wilderness, 5(2), 31–36.

Give us your feedback