Establishment and management of protected areas together with conservation, sustainable use and restoration initiatives in the adjacent land and seascape are central to Article 8 on "In-situConservation" of the Convention on Biological Diversity.

The Convention on Biological Diversity defines protected areas as:

"a geographically defined area which is designated or regulated and managed to achieve specific conservation objectives."

IUCN the world conservation union defines protected areas as:

"A clearly defined geographical space, recognised, dedicated and managed, through legal or other effective means, to achieve the long-term conservation of nature with associated ecosystem services and cultural values."

"In-situ Conservation" is defined by the Convention on Biological Diversity as the conservation of ecosystems and natural habitats and the maintenance and recovery of viable populations of species in their natural surroundings and, in the case of domesticated or cultivated species, in the surroundings where they have developed their distinctive properties.

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.

Articles 8(a) and 8(b) state that a system of protected areas forms a central element of any national strategy to conserve biological diversity. The word "system" in Article 8(a) implies that the protected areas of a country or region may be designated and designed to form a network, in which the various components may conserve different portions of biological diversity, often using a variety of approaches to management. In addition, Article 8(c) calls for the regulation and management of protected areas, while Article 8(d) aims to:

"Promote the protection of ecostystems, natural habitats and the maintenance of viable populations of species in natural surroundings."

Protected areas are a central part of the Convention in that the Parties themselves have consistently identified that their efforts to develop and maintain their national protected area system is the central element of their strategy to implement the Convention. Experience shows that a well designed and managed system of protected areas can form the pinnacle of nation's efforts to protect biological diversity. Such a system compliments other measures taken to conserve biological diversity outside protected areas.

Drawing on global experience, IUCN has developed a system of six management categories for protected areas. The most comprehensive dataset on protected areas world–wide is managed by the UNEP-World Conservation Monitoring Centre in partnership with the IUCN World Commission on Protected Areas (WCPA) and the World Database on Protected Areas Consortium. IUCN was instrumental in the preparation of early UN list of protected areas and the UN List is now prepared jointly by the IUCN-WCPA, and UNEP-World Conservation Monitoring Center (WCMC).

Based on the 2004 statistics, globally there are 104,791 protected areas listed in the World Database on Protected areas. The total area has also increased continuously from less than 3 million Km2 in 1970 to more than 20 million km2 2004. However, ecoregional and habitat representation remains uneven and coastal and marine ecosystems are particularly under represented. Existing systems of protected areas are not representative of all categories of biodiversity important for its conservation and sustainable use as set in Annex 1 to the CBD.