1 August 2011
This peatland habitat is found on flat or gently undulating ground in the English uplands where there is high rainfall. Under these ‘waterlogged’ conditions, peat forms from the partial decomposition of wetland plants, particularly Sphagnum mosses. The peat gradually accumulates, and over thousands of years can reach depths of several metres. The blanketing of the ground with peat gives this habitat its name.
Blanket bog can have a very varied micro-topography of hummocks and hollows, pools, ridges and Sphagnum lawns. In these situations they are very rich and diverse habitats providing important and specialised niches for bog-mosses, cotton-grasses, sundews and many insects.
It is one of the most extensive of all terrestrial habitats in England covering around 245,000 ha of the uplands. Of this peatland resource,165,000 ha are found within SSSIs.
In England, blanket bog is confined to the uplands because of climate. It extends from Cumbria and the Bowland Fells in the north-west, down through the central spine of England through the North and South Pennines and into the south-west uplands, especially Dartmoor.
Blanket bog is one of the rarest wildlife habitats in the world. Its importance is recognised in Europe by its inclusion in the EU Habitats Directive as a priority habitat.
In addition to its importance as a wildlife habitat, the role of blanket bog in the provision of a number of ecosystem services is significant. This includes the ability to capture and store large amounts of carbon, its role in securing high water quality and its ability to reduce flood risk downstream through slowing hydrological pathways. Blanket bogs also fulfil an important function as repositories of archaeological and palaeoecological material, with some blanket peat over 9,000 years old.
Much of the blanket bog in England is degraded to some degree and its condition is greatly influenced by activities such as drainage, managed burning and heavy grazing. These can damage the hydrology and properties of the peat, which in turn lead to loss of structural and floristic diversity (especially peat-forming species) of the blanket bog.
Wildfires and atmospheric pollution also damage blanket bog. The impact of current atmospheric deposition is not fully known as it is often masked by the effects of land management. Critical loads or levels of pollutants are however being exceeded across much of the English uplands.
Climate change, with the projection of wetter winters and drier summers may lead to a slowing down of peat formation. It is therefore even more important to secure restoration and sensitive management to protect the blanket bog resource.
The construction of moorland roads and tracks for land management, and the construction of windfarms that cause damage to and the loss of blanket bog habitat are current issues.
The Peat Compendium (of peatland management and restoration)