The use of parks and protected areas by visitors creates concern about appropriate levels of use because there are limits that define how much pressure from outside forces an ecosystem can endure before it experiences degradation, and there are thresholds that define visitor experiences. When researchers, park authorities, and policy makers are trying to determine appropriate usage levels of specific areas, they frequently rely on the rationale of carrying capacity, including social carrying capacity, which “focuses on the relationships among users of a park or protected area” (Dearden & Rollins).

Prior to determining the carrying capacity of a specific area, it is important to define carrying capacity. Prior to its use in the study of parks and protected areas, carrying capacity was commonly used in a variety of natural resource disciplines. The term has received broad use in wildlife and range management, where it was generally characterized as the number of animals of a given species that can be sustained in a known habitat (Dasmann 1964). Based on that characterization, carrying capacity has apparent equivalence in the study of parks and protected areas.One of the first uses of the term carry capacity, in relation to parks and protected areas, occurred in a 1935 report that asked, “How large a crowd can be turned loose in a wilderness without destroying its essential qualities? ” (Sumner 1935). The answer in that report was that recreational use of wilderness should be kept “within the carrying capacity.

” However, the first detailed use of carrying capacity in the management of parks and protected areas did not occur until the 1960s.At first, the focus was placed on the relationship between visitor use and environmental conditions. The hypothesis was that increased visitor use causes greater environmental impact, as measured by an array of variables, including destruction of vegetation and soil compaction. One of the first significant reports on the application of carrying capacity to parks and protected areas “… was initiated with the view that the carrying capacity of recreation lands could be determined primarily in terms of ecology and the eterioration of areas. However, it soon became obvious that the resource-oriented point of view must be augmented by consideration of human values” (Wager, 1964), as there was another dimension of carrying capacity that was receiving minimal consideration; dealing with social aspects of the visitor experience.

The point was that as more people visit an area, not only can the environmental resources of the area be affected, but so can the quality of the experience of the people visiting the area.The hypothesis was that increased visitor use triggers greater social impacts, as measured by crowding and related variables; therefore, carrying capacity, in relation to parks and protected areas has two key components: ecological and social. That dual component recognition is encompassed in a US National Park Service report (1997), which defines carrying capacity as “…the type and level of visitor use that can be accommodated while sustaining the desired resource and social conditions that complement the purpose of a park unit and its management objectives.There are no social components in Parks Canada’s definition of carrying capacity: “Carrying capacity is the equilibrium established between any life form and it’s environment. It is frequently expressed as a number indicating the population of any given animal a given area can support. ” (Parks Canada and Ecological Integrity) However, attempts to establish and apply social carrying capacity can be challenging because how would someone determine how much social impact, such as crowding, is too much?Additionally, in areas that experience increased visitor usage levels, it is unavoidable that there will be deterioration or alteration in the quality of the experience by the people using the areas; therefore, how much deterioration or alteration is appropriate or acceptable? This issue is often referred to as the “limits of acceptable change” and is essential to establishing social carrying capacity (Frissell and Stankey, 1972).

For example, what amount of visitor use of a specific area should be allowed, regardless of the ecological impact, before overcrowding is considered to have occurred and management intervention is needed?The optimum approach to social carrying capacity management mirrors Shelby and Heberlein’s (1986) method for both ecological and social carrying capacity: • Specify management parameters for a specific area • Specify impact parameters relevant to that area; and • Collect data at regular intervals to describe the current situation Appropriate management includes defining the type of visitor experience to be made available and then monitoring the situation to measure if acceptable conditions have been achieved (Graefe et al. , 1990).For example, a park or protected area may have an objective that includes social conditions, such as providing visitors with seclusion. This qualitative objective is beneficial, but it is ambiguous; therefore, it fails to provide management with what constitutes “providing visitors with seclusion,” and how is “seclusion” measured? The number of encounters with other people while in a given area could be a suitable indicator of seclusion; therefore, research involving the number of encounters with other people could determine if an area is “providing visitors with seclusion.For example, if the majority of visitors report that once they encounter more than five people per day, they no longer achieve an acceptable level of seclusion, the threshold for the number of encounters with people per day could appropriately be set at five.

An example of this type of research was conducted in Arches National Park in eastern Utah, where a program of social research was designed and conducted to help develop indicators and thresholds (Manning et al. , 1995).Firstly, visitors were asked questions about potential indicators of their quality of experience in the park or protected area. Secondly, visitors were asked to identify variables that contributed to or detracted from the quality of their experience. Several indicators of quality were identified, including the number of other visitors encountered. Then the research addressed thresholds, based on the standards of quality.

Visitors were asked to rate the acceptability of a series of pictures showing varying numbers of visitors at Delicate Arch.The research findings suggested that visitors generally accepted thirty people at one time at Delicate Arch; greater than thirty people at one time was generally judged as unacceptable, thus, the threshold. As a result of this research, thirty people at one time was established as the social carrying capacity threshold for overcrowding at Delicate Arch. Additional research was conducted throughout Arches National, and indicators and thresholds were established using comparable research techniques.

By defining indicators and thresholds, social carrying capacity can be applied by utilizing the instruments of a monitoring and management program. Threshold indicators can be monitored over time, and when a threshold has been reached, carrying capacity has been reached. At this point, management action would be required to ensure that thresholds are maintained or reduced to appropriate levels. This inclusion of social considerations, when using the rationale of carrying capacity, is central to contemporary park and outdoor recreation planning frameworks (National Park Service, 1993).However, setting the social thresholds can be problematic because there can be numerous and often conflicting rationale for selecting the types and amounts of thresholds. For example, legal precedents, political mandates, scientific evidence, public opinion, and historical significance are some of the issues that contribute to setting threshold criteria.

When setting the social carrying capacity thresholds, it is important to understand that the types of visitors that visit an area change as the carrying capacity changes.For example, as the number of general visitors participating in whale-watching activities increases, the number of specialized whale-watchers decreases, and if the number of visitors remains low, the number of specialist remains high (Duffus & Dearden, 1990). Traditional carry capacity theorists, like Dasmann may claim that social carry capacity is irrelevant because in their view, the equilibrium maximum of the population of an organism is most important, not visitor experiences and relationships. However, social carry capacity does play a valuable roll in enhancing the ecology of parks and protected areas.To increase the amount of people concerned about the ecology of parks and protected areas, the amount of people engaged with parks and protected areas also needs to increase because people care about what they know, and what they know is what interests them. The amount of people visiting parks and protected is decreasing (Searle, 2007); therefore, stronger efforts need to be made to increase the amount of visitors, thus, engaging more people, resulting in a greater public attention for parks and protected areas, including ecological onsiderations.

Yes, it could be argued that engaging more people with parks and protected areas will result in negative ecological impacts, such as destruction of vegetation and soil compaction because the greater the number of people on a land base, the greater the ecological impacts. However, treating parks and protected as commons is irresponsible; The National Parks present another instance of the working out of the tragedy of the commons. At present, they are open to all, without limit.The parks themselves are limited in extent -- there is only one Yosemite Valley -- whereas population seems to grow without limit. The values that visitors seek in the parks are steadily eroded. Plainly, we must soon cease to treat the parks as commons or they will be of no value to anyone.

What shall we do? We have several options. We might sell them off as private property. We might keep them as public property, but allocate the right to enter them. The allocation might be on the basis of wealth, by the use of an auction system.

It might be on the basis of merit, as defined by some agreed upon standards. It might be by lottery. Or it might be on a first-come, first-served basis, administered to long queues. These, I think, are all objectionable. But we must choose -- or acquiesce in the destruction of the commons that we call our National Parks.

(Hardin, 1968). To sustain parks and protected areas, decision makers must focus more on implementing and managing social carrying capacity thresholds because the relationships of the users has a direct impact, both positive and negative, on ecological carry capacity.