Ecological systems are responsible for life-supporting environmental services. They are essential for the survival of human beings because of the natural goods and services they provide. Humans derive many direct benefits from the living world. Thus, we have means in conserving biodiversity for the resources we use, for the ecosystem services it provides to us, for the pleasure we derive from living organisms and for ethical reasons. Protected areas are a vital contribution to the conservation of the world's natural and cultural resources. Their values range from the protection of natural habitats and associated flora and fauna to the maintenance of environmental stability of surrounding regions. Protected areas can provide opportunities for rural development and rational use of marginal lands, generating income and creating jobs, for research and monitoring, for conservation education and for recreation and tourism. As a result, all but a few countries have developed systems of protected areas. As international efforts to preserve biological diversity have evolved, it has become clear that protected areas are at the heart of any global strategy for success.