County Wildife Site Criteria for Cornwall Appendices

BLANKET BOG PHTGeneral DescriptionBlanket bog peat accumulates in response to the very slow rate at which plant material decomposesunder conditions of waterlogging. Peat depth is very variable, with an average of 0.5-3 m being fairlytypical but depths in excess of 5 m not unusual.Many of the typical blanket mire species, such as heather Calluna vulgaris, cross-leaved heath Ericatetralix, deer grass Trichophorum cespitosum, cotton grass Eriophorum species and several of the bogmoss Sphagnum species, occur throughout much of the range of the habitat, although their relativeproportions vary across the country.National ContextBlanket bog is one of the most extensive semi-natural habitats in the UK and ranges from Devon inthe south to Shetland in the north. Although most widespread in the wetter west and north, blanketbog also occurs in eastern upland areas.The total extent of blanket peat in the UK amounts to just under 1.5 million ha. There is no agreedfigure for the extent of blanket bog vegetation. In terms of national cover of blanket peat soil (in themain >0.5 m deep) England supports some 215 000 ha, Scotland approximately 1 060 000 ha, andWales has around 70 000 ha.Area of PHT in Cornwall (ha): 3300.02% National TotalNumber of polygons: 20The habitat is: RareDistribution by Administrative DistrictDistrict P K CK R CN NC ΣNumber 0 0 0 0 5 15 20Area (ha) 0 0 0 0 120 210 330Distribution by Natural AreaDistrict Pe Lz CKG BM Cu ΣNumber 0 0 0 20 0 20Area (ha) 0 0 0 330 0 330For this habitat the threshold is 0.3 haAppendix 4 - Information Relating to Priority Habitat TypesCounty Wildlife Sites Criteria