Carrying Capacity Image

Some excerpts from Simon McArthur’s chapter from Challenges in Tourism Research, Edited by Tej Vir Singh, published by Channel View Publications

Why carrying capacity doesn’t work

If tourists wanted to visit pastures and behave like cattle, then we could all use carrying capacity and the job of visitor and tourism management would be much easier.

We could set a maximum number, erect a fence and gate, and concentrate on other tasks – or nothing at all. Recreational or Tourist Carrying capacity (CC) assumes minimal diversity and minimal change – it’s a blunt and simple instrument that was not designed to work in the dynamic world of tourism.

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.

Relying on carrying capacity as a major way to manage tourism is not a good idea.

An example of its failure

One of my earliest requests to implement a simplistic carrying capacity was for Green Island (in far north Queensland, Australia).

The contained nature of islands offers one of the best settings to try and make CC work. A CC was notionally set and legislated into a Management Plan as 1,900 visitors per day or no more than 800 at any one time.

The calculation was unscientific – historic daily visitation of 1,700 that was deemed acceptable, with a notional 10% added for growth.

Having a daily limit and a limit at any one time was problematic to manage – if 800 visitors arrived all at once at dawn should we be more concerned than normal? If the maximum daily level was reached every day, at what point should we be concerned, if at all?

For 15 years, while the CC operated the only monitoring, passenger data from the ferry operator supported the CC – there was no monitoring of independent visitation and no other monitoring of the environment or experience.

Similar experiences were encountered working in tourism hot spots within protected areas across the World.

Figure 1. Green Island, with a Discrete Size and Controlled Access – Making it Ideally Suited to Try Carrying Capacity.

Figure 1. Green Island, with a Discrete Size and Controlled Access – Making it Ideally Suited to Try Carrying Capacity.


So the use of carrying capacity in tourism is deficient because it is typically based on untenable assumptions and a lack of recognition of the distinct roles of science and values.

Monitoring is essential to establish, defend and use the CC effectively. Generally, the only monitoring used is the number of visitors; and even this data can be rubbery.

Perhaps the challenge is to differentiate between a use limit policy, which comes after studied reflection of the use problem, and a carrying capacity as an inherent quality of a setting.

The common tendency to leave management objectives and monitoring out of the CC application has been equivalent to leaving the flight plan and navigation system out of a plane, but flying it anyway. Consequently, in most CC applications, we have lacked 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 of CC.

A better approach

Instead of trying to re-educate practitioners to use tourism / recreational CC in the way it was intended, it has been easier to create alternative models that feature the missing flight plan and navigation system. Consequently, we have seen a range of models based on setting management objectives and monitoring programmes that drive informed judgments on visitor management.  These models have included:

  • Limits of Acceptable Change (LAC)
  • Visitor Impact Management Model (VIMM)
  • Visitor Activity Management Programme (VAMP)
  • Visitor Experience and Resource Protection Model (VERP)
  • Tourism Optimisation Management Model (TOMM)

We recommend adoption of the Tourism Optimization Management Model (TOMM) for most tourism-focused clients, because:

  • the TOMM has the greatest capacity to grow stakeholder understanding and support for sustainable tourism management, particularly among those who may be skeptical of protected areas; and
  • through adaptive management, the TOMM still has a ‘stick’ that can be used to control situations needing it, but this can be done with reference to information that justifies it.

The TOMM has been successfully introduced in various parts of Australia, such as Kangaroo Island (South Australia), Dryandra Woodlands (Western Australia and the North Head Quarantine Station (Sydney Harbour National Park NSW. An application of the TOMM has just been developed for the Bahamas.

Below are the three parts of the TOMM and what each part does to create a healthy community, economy, visitor experience and environment.


Part 1 of the TOMM states what healthy tourism in the Exuma Cays looks like – each state is called an optimal condition. Optimal conditions are a desirable yet realistic state. Table 5 lists some potential optimal conditions.

Part 2 of the TOMM measures how close real life is to the optimal conditions. There are five elements of Part 2:

  1. Indicators
  2. Benchmarks
  3. Acceptable ranges
  4. Monitoring
  5. Reporting

Over time, the TOMM can be used to plot the results, and this can be used to identify trends and detect relationships, as shown in the fictitious example below (shaded like a traffic light as red at the top, yellow in the middle and green at the bottom).

Carrying Capacity - adaptive management

Adaptive Management is a process designed to handle uncertainties, including natural fluctuation and changing conditions inherent in all managed uses of components of biodiversity. It is an essential part of any management for sustainable use.

If an indicator is outside the acceptable range then it triggers Part 3 of the STM – adaptive management (what to do about it). First it needs to be determined if the problem or opportunity is being directly caused by tourism activity (for which the STM is equipped to respond), or if it is being indirectly caused by tourism, or if it is not related at all.


So the most important adaptive management response might be to find out more information, through a simple investigation or some research. If the issue is mild then an influential response may be all that is needed (such as advice, training or a change to marketing material). If the issue is bigger and more complex, then a range of responses might be needed, or a more controlling response might be required (such as stopping access or introducing a carrying capacity).

The TOMM tries to monitor, measure and estimate the divergence from optimal conditions of the amount of human activity that a site can biophysically sustain without severely changing its ecology or affecting the tourism experience. If management notices that some of the conditions we set as optimal are in risk, it can check how much apart from an acceptable range they are diverging and then decide on which actions or adaptive management responses to undertake so as to return the indicator to an acceptable range.

When introducing adaptive management, it is very important to continue monitoring – perhaps more frequently or over a wider scope. The monitoring will help show if the adaptive management is working, or if further adjustments and modifications need to be made to management actions.

Conclusion (not part of the chapter)

Sustainable tourism is a hell of a goal. Trying to simultaneously align economic prosperity with a healthy visitor experience, host environment and community is tough enough. But tourism is a fickle industry, renown for being treated as a luxury item. The environment contracts and people either stop taking holidays or reel them into shorter versions with shorter lead times but just as high expectations. This dynamic nature often limits innovation.

Many standard tourism plans that have tried to introduce actions to move tourism towards  sustainability. But plans are like a visitor’s photo – almost as soon as the shot is taken, the people and place changes. A five year plan is lucky to still be relevant after two years. Then there’s the problem of over promising and under delivering. Plans are like a whiteboard of problems, with a costly, time consuming action trying to solve every one.

The Sustainable Tourism Model (or STM) is like a living, breathing plan, but it only triggers action when reliable feedback says it is critical, and even them it has an armament of sliding scale responses to choose from. Now we monitor, learn and respond when needed, and when it’s fixed, we back off and return to monitoring, welcoming visitors and running tourism businesses.


Simon McArthur

Simon McArthur

Managing Director