 the unesco world network of biosphere reserves covers internationally designated protected areas, each known as biosphere reserves, that are meant to demonstrate a balanced relationship between people and nature (e.g. encourage sustainable development). ==mission== to ensure environmental, economic and social (including cultural and spiritual) sustainability through: * the development and coordination of a worldwide network of places acting as demonstration areas and learning sites with the aim of maintaining and developing ecological and cultural diversity, and securing ecosystem services for human well-being; * the development and integration of knowledge, including science, to advance our understanding of interactions between people and the rest of nature; * building global capacity for the management of complex socio-ecological systems, particularly through encouraging greater dialogue at the science-policy interface; environmental education; and multi-media outreach to the wider community. ==the network== right|thumb|350px|map showing the world network of biosphere reserves as of 2009. note: transboundary sites have been redistributed among the concerned countries for the locator map, hence, have been counted multiple times.  total membership has reached 621 biosphere reserves, including 12 transboundary sites, in 117 countries occurring in all regions of the world. this already takes into account some biosphere reserves that have been withdrawn or revised through the years, as the programâs focus has shifted from simple protection of nature to areas displaying close interaction between man and environment. {| class="wikitable sortable" |- ! unesco region ! number ofbiosphere reserves ! number ofcountries |- | africa | 64 | 28 |- | arab states | 271 | 11 |- | asia and the pacific | 124 | 23 |- | europe and north america | 289 | 34 |- | latin america and the caribbean | 117 | 21 |} 1 includes the intercontinental biosphere reserve of the mediterranean, shared between morocco and spain * source - unesco, 2012 ==references==  ==external links== * [
1977_in_the_environment Biodiversity Biomes Biosphere_reserves UNESCO