 Since then, it has been an international commitment on behalf of both governments and non-government organisations to maintain the networks that hold regular revisions for the succinct categorisations that have been developed to regulate and record protected areas.In 1972, the Stockholm Declaration of the United Nations Conference on the Human Environment endorsed the protection of representative examples of all major ecosystem types as a fundamental requirement of national conservation programmes.This has become a core principle of conservation biology and has remained so in recent resolutions - including the World Charter for Nature in 1982, the Rio Declaration at the Earth Summit in 1992, and the Johannesburg Declaration 2002.