Biosphere Reserves are internationally recognized, although they remain under the sovereignty of their respective countries and are not covered or protected by any international treaty. They are selected mainly for their scientific interest.
 Muniellos Biosphere Reserve - Fuentes del Narcea
In the year 2000 was declared a Biosphere Reserve by UNESCO and is currently the most protected natural area in the Principality. To see it you have to have a special permit and only twenty people per day are allowed. In addition to being the symbol of an entire region, Muniellos is also the largest forest mass in Asturias, the largest oak forest in Spain with more than 5.000 hectares, and one of the best preserved Atlantic forests in Europe.
In November of the year 2000, the International Coordinating Council of the Man and Biosphere Program (MAB), of Unesco, approved the declaration of Muniellos as a Biosphere Reserve, integrating it into the global network that protects the aforementioned body, expanding to all the territory of the Natural Park of Fuentes de Narcea, Degaña and Ibias in July 2003.
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 Reserve of the Biosphere Natural Park of Networks
The Network Park is located in the central-eastern mountain sector, covering the municipalities of Caso and Sobrescobio. It belongs to the Nalón region. It is a territory of great heritage values with a good number of environmental arguments. Its surface is 376,2 Km2. It is characterized for having an orography of medium and high mountain; dominated by limestone rock, the Atlantic forest, meadows and grasslands in the bottoms of the valleys.
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 Picos de Europa National Park Biosphere Reserve
The Picos de Europa, National Park, live up to its name and are one of the most beautiful landscapes of the continent. The landscape is overwhelmingly karstic, and includes gorges and gorges, immaculate rivers and valleys and large native forest stands. It has been declared by UNESCO in 2002 Biosphere Reserve.
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 Parque de Somiedo Biosphere Reserve
It is located in the southern area of the Principality, bordering the border of León. It is a territory dense in environmental and cultural values. Its surface occupies the not insignificant figure of 300 square kilometers. A whole world of unevenness: soft and steep reliefs that vary from the 400 meters to higher levels than the 2.100 meters.
Declared Natural Park in 1988 and Biosphere Reserve in the year 2000, the Somiedo Natural Park is also the holder of the European Charter for Sustainable Tourism, being the first Asturian Park to obtain it.
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 Las Ubiñas-La Mesa Biosphere Reserve
It is a magnificent mountain territory with a relief of strong contrasts, which is unbeatable for hiking and, in general, to fully enjoy nature. The main massif exceeds the 132 square kilometers with heights higher than the 2.000 meters. In total, the new Natural Park adds more than 42.000 hectares of extension and covers the entire council of Teverga, as well as part of those of Quirós and Lena.
The area declared as a Biosphere Reserve in the XXIV International Congress of UNESCO, meeting in Paris the 11 of July 2012, coincides with the Natural Park of Las Ubiñas-La Mesa, declared as such in 2006 as an extension of the territory that initially (year 1994) had been included in the Regional Network of Protected Natural Spaces under the figure of Protected Landscape of Peña Ubiña.
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 Oscos-Eo Biosphere Reserve
The Eo River, Oscos and Terras de Burón Biosphere Reserve was declared by the UNESCO MaB committee at the end of the year 2007.
The entire territory of Los Oscos is included within the Eo River Biosphere Reserve, Oscos and Terras de Burón. The 158.883 hectares declared a Biosphere Reserve have a high environmental value characterized by the variety of landscape units that make up the territory, which can be integrated into the different protection sectors.
 Reserve of the Ponga
The Ponga Biosphere Reserve was declared by the UNESCO MaB committee in julio de 2018, recognizes not only the beauty of a municipality loaded with life, but also the work that for hundreds of years made the ponguetos to model and conserve it. The inhabitants of the area believe that it will mean "an incentive" for nature-loving travelers to take notice of the pongueto council when it comes to choosing their destinations.
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