The Dyfi Biosphere (Welsh: Biosffer Dyfi)[1] is situated at the coast of south-central Wales in the estuary of the River Dyfi, and is a biosphere reserve representative of salt marshes and estuarine systems in the west of the United Kingdom. The estuary forms one of the most important wildfowl and shorebird centres in Wales and also comprises a Ramsar site.
Cors Fochno has a large expanse of primary raised mire and contains a high number of invertebrate species, including some of national and international importance. Upstream along the Dyfi Valley are remnants of native oak woodland. The site was declared in 1977, and covers an area of 1,589 hectares.[2]