All national parks, including Fort Matanzas, exist within the surrounding environment. Far from being islands of preserved lands separate from external influence, parks are integrally linked to the overall environment. When the environment as a whole has been perturbed in some way, the affects can often be observed, and are sometimes most apparent, within a park setting. This is because parks are largely free from the modern development that permeates our world. A change in, say, pollution levels in the air or water, the amount of man-made noise, the presence of non-native pests in a forest, or even the number of stars visible in the night sky, is more noticeable in a park than in a more altered setting. It is this characteristic of parks, their relative naturalness compared to almost any other place, which makes them bellwethers for the state of the environment as a whole. They are natural laboratories in which the effects of man's impact on the environment can best be measured.