Where does blanket bog occur?

Blanket bogs occur in cool wet climates, i.e. areas with high rainfall, large numbers of rain days, and low levels of evapotranspiration. This allows peat to develop across the landscape, rather than be limited to individual depressions or catchments. It is from this 'blanketing' of the landscape that the term blanket bog is derived. blanket bog that still supports significant areas of plant species that normally form peat is referred to as active blanket bog, a priority habitat under the EC Habitats Directive. Large areas of blanket bog persist despite currently not actively forming peat, something that may have a significant bearing on their conservation management or restoration.

Due to the climatic conditions required for blanket bog formation, they have a limited global distribution, and are only found on the east coast of Canada, Southern Alaska, the Pacific NW of the USA, Tierra del Fuego, and small parts of Europe, NE Asia, Tasmania, and New Zealand. In Europe, blanket bogs are found primarily in the UK and Ireland, and whilst there are no agreed estimates of the total area of blanket bog vegetation in Britain, it has been estimated that 10-15% of the world's blanket bog occurs in Britain.

In Wales, it is estimated that 70,000 ha of blanket peat occur, although probably in excess of 10% of this no longer supports blanket bog vegetation, and a significant proportion of the remaining area is likely to not support active blanket bog. The Berwyn and South Clwyd Mountains SAC (c. 27,200 ha) supports the most extensive tract of near-natural blanket bog in Wales, whilst the Migneint-Arenig-Dduallt SAC (20,000 ha) supports the largest area of blanket bog in North Wales after the Berwyn. In both areas, the blanket bog vegetation is dominated by heather and hare's-tail cotton grass (Eriophorum vaginatum), with cross-leaved heath (Erica tetralix) and Bog Sphagnum mosses.