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Carrying capacity – it's time to let it go
by Simon McArthur


Carrying capacity is appealing for its simplicity, but this is the very reason why it is fundamentally flawed when applied to human beings.


Carrying capacity assumes all other variables are removed, and that both the environment and people do not change. Impact monitoring has proven over and over again that environmental resilience ebbs and flows with factors such as seasonality, intensity of use and recovery periods between use. Monitoring has also shown that different people create different impacts, based on a range of variables including type of activity, clothing, behaviour and equipment.

Carrying capacity is a blunt instrument that is not designed to accommodate these variables and it's apparent simplicity discourages most people from considering these variables.


In the mid 1970s, recreational carrying capacity began to be mooted as the major model for managing visitor impact.

In response, the U.S. Department of Interior reviewed the potential of recreational carrying capacity and prepared guidelines for its use. The review looked at existing literature, past research and use of the model, evaluated standards currently used for their application as indicators, then surveyed user groups and recreation planners and heritage managers to explore attitudes and support for the model.

Guidelines were developed to aid recreation planners and heritage managers in determining whether to develop a recreational carrying capacity model and if so, how to go about it at the site level. The study revealed the following:

Park planners were more interested in protecting the resource or meeting recreation demand than providing a high quality experience.

There were significant differences in opinion between planners and user groups, particularly in relation to optimum capacities for such activities as bushwalking, water skiing, pool swimming, power boating and shoreline fishing.

Several managers had established capacity limits based on the availability of support facilities rather than the optimum recreational carrying capacity - in essence managers were already focusing on a maximum number rather than the entirety of the model as it was originally proposed.


By 1980 the U.S. National Parks Service had established carrying capacity limits in 21 per cent of its entire estate. Since then the notion to develop recreational carrying capacity models has remained popular but their actual application has been sporadic, uncoordinated and largely not evaluated.


Within this context, the actual applications of recreational carrying capacity have nonetheless managed to occur in planning, site design, development, and administration. Planning use often involved evaluating the size and character of alternative sites and predetermining optimum levels of use for various locations.

Site design and development use have involved assigning activities to areas according to natural limits, and identifying suitable position between the activities. However, the emphasis by most heritage managers has been on physical capacity applied to site design and development. Here are a few examples.

Australia: The Daintree National Park (Queensland), based on the physical limitations of defined vehicle parking spaces, Green Island (Queensland) has a capacity of 1,900 visitors per day or no more than 800 at any one time, Point Nepean National Park (Victoria) where the limit is 600 visitors at any one moment in time;

New Zealand: A limit of 500 visits per year has been set for the sub-Antarctic islands, 200 persons at any one moment in time for the Waitomo Caves, and 160 persons on any day during the period that the Milford Track is open to public access;

Bermuda: A capacity of 120,000 cruise ship passengers during the peak visitation period was set by local authorities for Bermuda.

Canada: The carrying capacity concept was used to review tourism development strategies in Ontario; the result was the identification of specific zones with high potential for tourism development, based on competition for resources between residents, owners of second homes and tourists;

Cambodia: The Angkor World Heritage Site has a capacity of 300 to 500 visitors at any one time and an annual capacity of 500,000 (these capacities assume visitors will make two visits to the site during their stay;

South Africa: Capacity limits have been applied to the Kromme River Estuary and the Infanta area, South Cape, and in the United States Yosemite Valley, Yosemite National Park, Cache National Forest in Utah.


The applications that have been established have been full of assumptions and inconsistencies. A good example of the assumptions and subjective judgements is Green Island in far north Queensland. If the maximum daily level was reached every day, Green Island would receive 693,500 visitors in a year, over twice the current level. Any visitor management model that cannot be defended is unlikely to gain or at least maintain the support of stakeholders.

Despite the concept of recreational carrying capacity being over 30 years old, it remains, in practice, highly elusive. It is commonly recognised that there are no fixed or standard tourism recreational carrying capacity values. Rather, carrying capacity varies, depending upon place, season and time, user behaviour, facility design, patterns and levels of management, and the dynamic character of the environments themselves. Moreover, it is not always possible to separate tourism activity from other human activities.

Clearly then it is relatively easy to argue that there is no such thing as a single recreational carrying capacity for any given heritage site and that any capacity put forward is highly subjective, and thus difficult to defend.

Recreational carrying capacity is multi-faceted or multi-dimensional. Its determination will therefore be all the more difficult because of the range of activities and environmental variables involved; and because we still do not know sufficient about the relationships between varying levels of use and changes in the biological and physical character of the site on the one hand and changes in the degree of personal satisfaction obtained in the other. A somewhat paradoxical situation exists: in fact there is ‘spare capacity' in the areas which are already intensively used, but the visitors frequenting the less used parts may already consider existing levels of use to be too high and the area over used.

Nearly a decade later, with a considerable amount of impact related research undertaken, academics and practitioners continued to have problems with the complexities of recreational carrying capacity and continued to question the reality of ever establishing a reliable model. One of the architects of recreational carrying capacity, George Stankey once wrote:

Physical-biological impact is a complex phenomena. It does not bear a direct linear relationship to use; in fact, use intensity is less helpful than other variables (eg. method of travel, season of use) in explaining the degree of impact sustained... In general, knowledge of other ecological consequences associated with recreation use is poor. Impacts on wildlife behaviour, air quality, or water quality are understood in only descriptive terms.

We lack the ability to predict, in quantitative terms, the consequences of alternative levels, types and patterns of use on the physical-biological environment, a serious shortcoming in our efforts to develop the potential carrying capacity concept.

Stankey suggested four propositions about the nature of recreational carrying capacity nature:

1. Its determination is ultimately a judgmental decision
2. Decisions depend on clear management objectives
3. The range of available alternative opportunities must be taken into account
4. It is a problematic concept, not an absolute measure


Policies concerning carrying capacities are based on the assumption that recreational impacts are directly related to the amount and type of use. However, ecological and human behaviour factors do not allow for such a simple and direct relationship between amount of impact and use.

Carrying capacity is the lazy man's answer to visitor management, just like fences and regulations! Sophisticated models that incorporate feedback (monitoring) and adaptive management are more accountable and socially just.

Models such as the Limits of Acceptable Change, Tourism Optimisation Management Model and Visitor Experience and Recreation Program can be set up as small scale models that can be progressively expanded as their value is proven. The challenge is to acknowledge that the complexity of visitor management requires an integrated and long term approach.


Simon has 16 years experience working with ecotourism planning, development and operations across the world, and straddles the divide between the tourism industry and heritage managers. He specialises in creating special interest tourism operations that are authentic, minimal impact and sufficiently viable to conserve the site that they depend on.

Simon's practical experience is backed up by several books and numerous papers on heritage and visitor management, a PhD in tourism impact management, and regular speaking engagements on ecotourism, cultural tourism and tourism impact management across the world.

Simon works as Product Development Manager for EcoPoint Management, an ecotourism company based in Australia. His current focus is the adaptive reuse of Sydney's historic Quarantine Station into a 90 room resort with health retreat and interpretive tours). He is completing a Master of Business Administration.


This paper represents a synthesis of a PhD thesis 'Visitor management in action, an analysis of the development and implementation of visitor management models at Jenolan Caves and Kangaroo Island,' by Simon McArthur, and held at the University of Canberra, Australia. References are available on request.



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