Iles et Mer d'Iroise

Corentin250292/Wikimedia Commons
Île de Sein, Iles et Mer d'Iroise Biosphere Reserve, France

This Biosphere reserve comprises three inhabited islands (Ouessant, Sein and Molène), as well as the Molène archipelago which consists of around twenty smaller islands, plus the waters between the islands. All the major ecosystems of the Atlantic biogeographical region (island, coastal and marine) are represented: the marine environment, beaches, cliffs with Atlantic coastal vegetation, heathlands and grasslands.

Declaration Date: 1988 (extended and renamed in 2012)
Administrative Authorities: Parc naturel régional d’Armorique; Parc naturel marin d’Iroise
Surface Area: 99,149.33 ha
Core area(s): 45,049.33 ha
Buffer zone(s): 54,100 ha

Latitude: 47º 59'N - 48º 31'N
Longitude: 4º 41'E - 5º 12'E
Centre Point: 48º 22'N - 4º 56'E

Ecological Characteristics

Corentin250292/Wikimedia Commons
Snow bunting, Iles et Mer d'Iroise Biosphere Reserve, France

Iles et Mer d'Iroise Biosphere Reserve, located on the coast of Brittany, comprises a marine park and the island of Sein, small rocky marine islands and islets and open marine areas to a depth of -20 meters with strong currents and a high tidal range.

It is of significance from a biodiversity point of view since it encompasses a variety of habitats e.g. for more than 300 species of seaweed, large sea bird colonies and populations of basking shark (Cetorhinus maximus) and grey seal (Halichoerus grypus).


The Isle of Ouessant reaches no higher than 60 meters in altitude and its landscape is one of meadows grazed by sheep and crisscrossed with stone walls and numerous hamlets.

Islands; marine waters and sandy bottoms; marine algae communities dominated by Fucus spiralis, F. vesiculosus and Laminaria digitata; gravel, rocks and rocky bottoms (Zostera seagrass beds, Laminaria and kelp seaweed communities); sandy beaches; pebble beach communities with Beta maritima and Crambe maritima; rocky coasts and islets; coastal marshlands; coastal grasslands; dry moorlands; enriched pasturelands; scrublands (ferns, willows); mesotrophic backwaters.

Socio-economic characteristics

Havang/Wikimedia Commons
Port of the island of Sein.

Daily tourism is a significant element of the local economy, providing the basis for commercial activities on the islands. However, also fishing activities remain important.

Numerous educational and training activities are carried out in the biosphere reserve, such as guided visits for school classes, exhibits, public information meetings and internships.

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                                                                                    Last updated: February 2015

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