Carrying Capacity Calculator

The concept of carrying capacity (CC), originally from the field of ecology, is defined as the maximum supported population number for a given environment, until there are no sufficient resources to maintain population growth, and degradation starts to occur. One of the first usages of this concept in the Malthusian population theory (Seidl,1999), which states the exponential growth of the human population is limited to existing resources (which cannot grow exponentially), turning the growth model into a logistic model, being its upper limit the CC of the human population.

The concept has been applied in multiple other fields, such as economy, biology, and population studies (Kennell, 2014), and has had various definition iterations according to its application. It has also been approached in tourism studies, being known as tourism carrying capacity (TCC).  

According to the UNWTO, it is defined as “the maximum number of people that may visit a tourist destination at the same time, without causing destruction of the physical, economic, social-cultural environment and an unacceptable decrease in the quality of visitors’ satisfaction” (WTO,1981). Getz (1983) stated there are 6 TCC categories: physical, economic, perceptive, social, ecological, and political. Respectively, each category represents the maximum usage of a tourist resource before physical deterioration, excessive economic dependence, perception of overcrowding by tourists, ecological damage to nature, and political instability.

Three levels of TCC are proposed in the highly cited methodology proposed by Cifuentes (1992):

• Physical Carrying Capacity (PCC): This level of TCC represents the maximum number of visitors that can be physically accommodated into an area over some time. It is calculated using the following formula:

    PCC = A/Ap *Rf 

    where A is the available area for tourism activity, Ap is the area used per tourist for a specific type of tourism activity, and Rf is the rotation factor, which represents the number of visits within a period (usually a day). To assess instant PCC, the rotation factor can be omitted from the equation. The Ap parameter is culture and activity-dependent, as different cultures perceive the ideal space per pedestrian differently, and each tourism activity requires different spaces per pedestrian.

• Real Carrying Capacity (RCC): This value is derived from a previously calculated PCC, applying corrective factors with different natures (e.g., physical, ecological, economical), specific to the location.  The formula to assess RCC is:

        RCC = PCC x (cf1 x cf2 x … cfn)

    where \textit{cf1...cfn} are the defined corrective factors. Each factor is calculated using the expression:

        cf = 1 - Lm/Tm

    where Lm is the limiting magnitude of the factor, and Tm is the total magnitude of the factor.

• Effective Carrying Capacity (ECC): The final level of TCC is derived from the RCC, multiplied by the management capacity factor.

        ECC = RCC x Mc

    where Mc is the management capacity of the site. This variable is often determined by the adequacy of the available infrastructure, equipment, and staff for the tourism activity.

The tool allows the calculation of these levels of TCC over polygons, calculating the available area (A) with OpenStreetMap data.