The Biosphere Reserves are areas of terrestrial and coastal / marine ecosystems, or a combination of both, internationally recognized into the  MAB Programme  of UNESCO. Usually it applied to territories that host natural values in line with their cultural and where the people freely expressed the will to implement a model of sustainable development that respects these values heritage.

In the Western Iberian area, there are currently two Biosphere Reserves: Sierras de Béjar and France and Monfragüe.