Social carrying capacity of parks and outdoor recreation areas.

Concern over the increased use of parks and outdoor recreation areas is a perennial issue. Visitors can trample fragile vegetation, erode soil, pollute water, and frighten wildlife. Moreover, too many visitors can cause crowding, conflict, and other social impacts, thereby degrading the quality of the recreation experience. Concern over these issues was documented by the Outdoor Recreation Resources Review Commission in the early 1960s and has grown in importance as visitation to most parks and outdoor recreation areas has continued to increase. These issues are often incorporated within the conceptual framework of carrying capacity. In its most generic form, carrying capacity can be defined the amount of visitor use that can be appropriately accommodated with in a park or outdoor recreation area.

The underlying concept of carrying capacity has a rich history in the natural resource professions. In particular, it has proven a useful concept in wildlife and range management, where it generally refers to the number of animals of any one species that can be sustained in a given habitat. Carrying capacity has obvious parallels and intuitive appeal in the field of parks and outdoor recreation. However, the first rigorous applications of carrying capacity to outdoor recreation did not occur until the 1960s.

These initial scientific applications of carrying capacity suggested the concept was more complex in this new management context. At first, as might be expected, the focus was placed on the relationship between visitor use and environmental conditions. The working hypothesis was that increased visitor use causes greater environmental impact as measured by soil compaction, destruction of vegetation, and related variables. It soon became apparent, however, that there was another dimension of carrying capacity dealing with social aspects of the visitor experience. An early and important report on the application of carrying capacity to outdoor recreation, for example, reported that the study ". . . was initiated with the view that the carrying capacity of recreation lands could be determined primarily in terms of ecology and the deterioration of areas. However, it soon became obvious that the resource-oriented point of view must be augmented by consideration of human values." (Wager, 1964).

The point was that as more people visit an area, not only can the environmental resources of the area be affected, but so too can the quality of the visitor experience. Again, the working hypothesis was that increased visitor use causes greater social impacts as measured by crowding and related variables. Thus, as applied to outdoor recreation, carrying capacity has two components: environmental and social.

The early scientific work on carrying capacity has blossomed into an extended collection of literature on social aspects of outdoor recreation and their application to carrying capacity (Stankey and Lime, 1973; Manning, 1986; Shelby and Heberlein, 1986; Kuss et al., 1990). But despite the impressive literary base, efforts to determine and apply social carrying capacity have often been met with frustration. The principal difficulty lies in determining how much social impact, such as crowding, is too much. Given the substantial demand for outdoor recreation, some decline or change in the quality of the visitor experience (some perceived crowding) is inevitable. But how much decline or change is appropriate or acceptable? This issue is often referred to as the "limits of acceptable change" and is fundamental to social carrying capacity determination (Frissell and Stankey, 1972).

This issue is illustrated in Figure 1, in which two hypothetical relationships between visitor use and crowding are shown. It is clear from both that visitor-use level and perceived crowding are related: increasing numbers of visitors cause increasing percentages of visitors to report feeling crowded. However, it is not clear at what point carrying capacity has been reached. The relationships in Figure 1 illustrate that some crowding is inevitable, given even relatively low levels of visitor use. Thus, some level of crowding must be tolerated if parks and outdoor recreation areas are to remain open for public use. For the relationship defined by line A, X1 and X2 represent alternative levels of visitor use that result in alternative levels of crowding, as defined by points Y1 and Y2, respectively. But which of these points -- Y1, Y2, or some other point along the horizontal axis -- represents the maximum amount of crowding that is acceptable?

[Figure 1 ILLUSTRATION OMITTED]

To emphasize and further clarify this issue, some writers have suggested distinguishing between descriptive and prescriptive components of social carrying capacity determination (Shelby and Heberlein, 1986). The descriptive component of social carrying capacity focuses on factual, objective data such as the relationships in Figure 1. For example, what is the relationship between the amount of visitor use and visitor perceptions of crowding? The prescriptive component of social carrying capacity determination concerns the seemingly more subjective issue of how much impact or change in the recreation experience is acceptable. For example, what level of perceived crowding should be allowed before management intervention is appropriate?

Indicators and Standards of Quality

Recent experience with carrying capacity suggests that answers to the above questions can be found through formulation of indicators and standards of quality (Stankey et al., 1985; Stankey and Manning, 1986; Graefe et al., 1990; Shelby et al., 1992). This approach to carrying capacity focuses on defining the type of visitor experience to be provided and then monitoring conditions over time to assess whether acceptable conditions have been maintained. Indicators of quality are specific, measurable variables that define the resource and social conditions to be managed within a park or out door recreation area. Standards of quality define the minimum acceptable condition of each indicator variable.

A brief example may help illuminate these definitions. An initial description of a park or outdoor recreation area may suggest that social conditions should offer visitors opportunities for solitude. This is a broad, qualitative statement that is helpful in general terms, but is not specific enough to guide management. For example, what constitutes "opportunities for solitude," and how is "solitude" to be measured? Indicators and standards of quality provide answers to these types of questions. It may be determined through a program of research that the number of encounters with other groups along trails is a key measure of opportunities for solitude. Thus, number of trail encounters with other groups may be a good indicator of quality. Moreover, most visitors may report that once they encounter more than three groups per day they no longer achieve an acceptable level of solitude. Thus, the standard of quality for the number of trail encounters per day might be most appropriately set at three.

By defining indicators and standards of quality, carrying capacity can be applied by means of a monitoring and management program. Indicators of quality can be monitored over time. Once standards of quality have been violated, carrying capacity has been reached. At this point, management action is required to ensure that standards of quality are maintained. This approach to carrying capacity is central to contemporary park and outdoor recreation planning frameworks, including Limits of Acceptable Change (Stankey et al., 1985); Visitor Impact Management (Graefe et al., 1990); and Visitor Experience and Resource Protection (National Park Service, 1993).

A Normative Approach to Standards of Quality

Not surprisingly, one of the most problematic issues in this contemporary approach to carrying capacity has been setting standards of quality. Such standards may be based on a variety of sources, including legal and administrative mandates, agency policy, historic precedent, expert judgment, interest group politics, and public opinion (especially that derived from outdoor recreation visitors). This latter source has special appeal, as it involves those people most directly interested in and affected by carrying capacity decisions and related management actions.

Research on visitor-based standards of quality has relied heavily on normative theory and related empirical techniques. Developed in the fields of sociology and social-psychology, norms have attracted considerable attention as an organizing concept in outdoor recreation research and management. In particular, normative theory and methods have special application in understanding and measuring crowding and other social impacts of outdoor recreation. As applied in outdoor recreation, norms are generally defined as standards that individuals and groups use for evaluating social and environmental conditions (Shelby and Vaske, 1991). If visitors have normative standards concerning relevant aspects of recreation experiences, then such norms can be studied and used as a basis for formulating standards of quality. In this way, carrying capacity can be determined and managed more effectively.

Application of norms to standards of quality in outdoor recreation is best described by Shelby and Heberlein (1986) and Vaske et al. (1986). These applications have relied heavily upon the work of Jackson (1965), who developed a methodology -- return potential curves -- to measure norms. Using these methods, the personal norms of individuals can be aggregated to test for the existence of social norms or the degree to which norms are shared across groups. Normative research in outdoor recreation has focused largely on the issue of crowding (Shelby and Heberlein, 1986; Manning et al., 1995; Lewis et al., 1996), but also has been expanded to include other potential indicators of quality, including ecological impacts (Shelby et al., 1988; Manning et al., 1995); wildlife management practices (Vaske and Donnelly, 1988); minimum stream flows (Shelby and Whittaker, 1990); and levels of facility development (Ormiston et al., 1997).

A Case Study

The carrying capacity framework described above is now being applied in the United States' national park system. The first application focused on Arches National Park in eastern Utah. A program of social research was designed and conducted to help develop indicators and standards of quality (Manning et al., 1995; Manning et al., 1996a; Manning et al., 1996b). The first phase of research addressed potential indicators of quality. Using open- and close-ended questions, visitors were asked to identify variables that contributed to or detracted from the quality of their experience in the park. Several indicators of quality were identified, including the number of visitors at attraction sites such as Delicate Arch.

The second phase of research addressed standards of quality. As part of this study, visitors to Delicate Arch were asked to rate the acceptability of a series of photographs showing a range of visitors at this site. These photographs were developed using computer-based image capture technology. Study findings suggested that visitors generally found up to 30 people at one time at Delicate Arch to be acceptable; more than 30 people at one time was generally judged as unacceptable.

Based on these findings, 30 people at one time was established as a standard of quality for Delicate Arch. To help ensure that this standard of quality is not violated, the parking lot that serves the trail to Delicate Arch has been appropriately sized, and the number of people at one time at Delicate Arch is regularly monitored. Other indicators and standards of quality were determined throughout the park using similar research methods.

Conclusion

Carrying capacity has been a central issue in outdoor recreation for several decades. Research and management experience have substantially enhanced our understanding of carrying capacity and our ability to apply it to a variety of parks and outdoor recreation areas. Contemporary approaches to carrying capacity focus on developing indicators and standards of quality. Moreover, normative theory and methods provide a conceptual and empirical approach to developing standards of quality. The frameworks described above provide a basis for managing parks and outdoor recreation areas within a defined carrying capacity. They also provide an agenda for further research and experimentation.

References

Frissell, S.S. and G.H. Stankey. 1972. Wilderness environmental quality: Search for social and ecological harmony. Proceedings of the Society of American Foresters Annual Conference, Washington, D.C.

Graefe, A.R., F.R. Kuss, and J.J. Vaske. 1990. Visitor impact management: The planning framework. Washington, D.C. National Parks and Conservation Association.

Jackson, J. 1965. Structural characteristics of norms. In I.D. Steiner and M.F. Fishbein (Eds.) Current studies in social psychology. New York: Holt, Rinehart, Winston, Inc.

Kuss, F.R., A.R. Graefe, and J.J. Vaske. 1990. Visitor impact management: A review of research. Washington, D.C. National Parks and Conservation Association.

Lewis, M., D.W. Lime, and D.H. Anderson. 1996. Paddle canoeists encounter norms in Minnesota's Boundary Waters Canoe Area Wilderness. Leisure Sciences 18:143-160.

Manning, R.E. 1986. Studies in outdoor recreation. Corvallis, OR: Oregon State University Press.

Manning, R. E., D.W. Lime, M. Hof, and W.A. Freimund. 1995. The Visitor Experience and Resource Protection (VERP) process: The application of carrying capacity at Arches National Park. The George Wright Forum 12(3):41-56.

Manning, R.E., D. Johnson, and M. Vande Kamp. 1996a. Norm congruence among tour boat passengers to Glacier Bay National Park. Leisure Sciences 18:125-141.

Manning, R.E., D.W. Lime, W.A. Freimund, and D.G. Pitt. 1996b. Crowding norms at frontcountry sites: A visual approach to setting standards of quality. Leisure Sciences 18:39-59.

National Park Service. 1993. Special report. VERP: A process for addressing visitor carrying capacity in the national park system. Working draft paper. National Park Service Denver Service Center, Denver CO, 20 pages.

Ormiston, D., A. Gilbert, and R. Manning. 1997. Indicators and standards of quality for ski resort management. Journal of Travel Research.

Shelby, B., and T.A. Heberlein. 1986. Carrying capacity in recreation settings. Corvallis, OR: Oregon State University Press.

Shelby, B., J.J. Vaske and R. Harris. 1988. User standards for ecological impacts at wilderness campsites. Journal of Leisure Research, 20(3): 245-256.

Shelby, B., and D. Whittaker. 1990. Recreation values and instream flow needs on the Delores River. Paper presented at the Third Conference on Society and Resource Management. College Station, Texas.

Shelby, B. and J.J. Vaske. 1991. Using normative data to develop evaluative standards for resource management: A comment on three recent papers. Journal of Leisure Research 23(2):173-187.

Shelby, B., G. Stankey, and B. Shindler. (Eds.) 1992. Defining Wilderness Quality: The Role of Standards in Wilderness Management--A Workshop Proceedings. USDA Forest Service General Technical Report PMW-GTR-305, 114 pages.

Stankey, G.H. and D.W. Lime. 1973. Recreational carrying capacity: an annotated bibliography. USDA Forest Service General Technical Report INT-3, 45 pages, Intermountain Forest and Range Experiment Station, Ogden, UT.

Stankey, G.H., D.N. Cole, R.C. Lucas, M.E. Peterson, S.S. Frissell, and R.E Washburne. 1985. The Limits of Acceptable Change (LAC) system for wilderness planning. USDA Forest Service General Technical Report INT-1760.

Stankey, G. H., and R. E. Manning. 1986. Carrying capacity of recreation settings. The President's commission on Americans outdoors: A literature review. Washington, D.C.: U.S. Government Printing Office, pp. 47-57.

Vaske, J. J., A.R. Graefe, B. Shelby, and f Heberlein. 1986. Backcountry encounter norms: Theory, method, and empirical evidence. Journal of Leisure Research, 18(3):137-153.

Vaske, J. J. and M.P. Donnelly. 1988. Normative evaluations of wildlife management: A comparison of three publics. Paper presented et the National Recreation and Park Association Congress, Indianapolis, IN.

Wagar, J.S. 1964. The carrying capacity of wild lands for recreation. Forest Science Monograph 7, Society of American Foresters, Washington, D.C..

RELATED ARTICLE: Research Into Action: Social Carrying Capacity

Introduction

Social carrying capacity refers to the amount of visitor use that individual visitors can sustain before the number of visitors begins to intrude upon individual quality of the experience. Social carrying capacity, unlike the more traditional carrying capacity, is not an exact science and is highly dependent upon individual perceptions of the experience.

Impact of this Research

An awareness of the potential of social carrying capacity to impact upon individual visitor experiences allows resource managers of urban, regional, state and national parks and recreation areas to understand visitor behavior and attempt to accommodate needs. The more difficult part of this research is the lack of understanding exactly "how to" deal with the social crowding issue. While indicators of crowding may be present, the more difficult part is to identify what is a minimum acceptable condition of each indicator. Managers can be aware of this research and begin to improve the quality of the experience for individual visitors.

How to Use this Research

* Gather and review the literature for application in your system. While the bulk of the literature applies to resource-based settings, it is applicable to municipal settings.

* Establish a research base for your area and develop minimum acceptable conditions for crowding

* Establish, in urban areas, designs that maximally impact upon crowding and have the potential to provide individuals with a greater feeling of the leisure experience

For More Information

Shelby, B., and T A. Heberlein. 1986. Carrying capacity in recreation settings. Corvallis, OR. Oregon State University Press.

Research Into Action is published monthly by the society of Park and Recreation Educators, National Recreation and Park Association. As an Accompaniment to "Research Update," its goal is to turn research finding into field action by highlighting management strategies. Founding editors are Dr. Ruth Russell and Dr. Daniel D. McLean, Department of Recreation and Park Administration, Indiana University.

Robert E. Manning is chair of the Recreation Management program at the University of Vermont. He conducts research on park and wilderness management and is the author of Studies in Outdoor Recreation, published by Oregon State University Press.

Research Update is edited by Dr. Irma O'Dell of Southern Illinois University at Carbondale.