A key concept when dealing with current environmental problems is that the resources of our planet are limited.

One way of determining how many organisms our planet and its ecosystems can support is by looking at the carrying capacity. The carrying capacity can be defined as "the number of individuals an environment can support without significant negative impacts to the given organisms and its environment".

In this article I will look at the basic concepts of the carrying capacity as applied to organisms in general and to humans.

However, in the second part of this article I will look at how carrying capacity specifically applies to tourism which is a major source of income for this island.

Before going further into the topic of carrying capacity, there are a few rules and terms one has to be familiar with. Populations in an area that are below the carrying capacity usually increase while those above the carrying capacity usually decrease.

Therefore, the factor that keeps the population size at equilibrium is known as the regulating factor. Examples of these regulating factors include, space, food supply or sunlight in the case of plants.

What must also be kept in mind is that the number of individuals that an area can support, that is, its carrying capacity can change over time for a variety of reasons, like food and water availability, environmental conditions like temperature, humidity and the availability of suitable habitat due to changing environmental conditions or from habitat destruction or fragmentation.

There are also situations where populations get so large that they temporarily exceed the carrying capacity of the area they occupy, after which they crash (that is, they suffer a dramatic decrease in number).

But generally the population size fluctuates around the carrying capacity of the area, partly because of natural selection, in this case as the environmental conditions change.

Those individuals whose genetic make-up enables them to be better adapted to the new environment stay in the population. While those individuals less suited leave the population by migrating or by death.

But due to the variety of factors acting at the same time, one may influence the carrying capacity faster than the other. For example, the build up of toxic materials in an area might occur slower than the destruction of habitat by a bush fire.

Carrying capacity can be applied to different components of the environment, with each component being affected by different factors. For instance, the carrying capacity of an ecosystem is affected by three factors, the amount of resource available, the size of the population of organisms and finally the amount of resources the individual is consuming.

Of course certain factors affect the population size of the species that the environment can sustain; these include mainly food, water and habitat. But when it comes to human populations, additional factors come into play, for instance, the level and quality of medical care and sanitation. Both of these factors determine how fast communicable diseases like yellow fever and cholera are spread.

Therefore, although the concept of carrying capacity can be applied to human populations as well, but there is much speculation about whether it is accurately applied.

reason for this speculation is that humans have great control over their environment, for instance, if food availability is the regulating factor and it is at a low level, then through the use of fertilisers and machinery humans can cultivate crops thus, eliminating this regulating factor.

One way of assessing the carrying capacity on human populations is by examining the ecological footprint. In this method, the planet's historically regeneration rates (also known as biocapacity) are compared against historical human demand in the same year. Therefore, one can say that for example, for the year 2004 country (humanity's demand) exceeded the planet's biocapacity by 25 percent.

Therefore we can see that the carrying capacity of a species is affected and regulated by many factors.

However, when it comes to human populations the concept of carrying capacity is further complicated by our ability to modify our environment and in turn regulating factors like food supply by agriculture. But the carrying capacity of humans can be assessed by utilising the concept of ecological foot printing.