Blanket Bog - Border Mires, Butterburn Flow - Duncan Bridges
What is it?
Wild areas with spiky rushes, carpets of moss and wet, peaty soils, blanket bogs are a familiar feature of our dramatic upland landscapes. They smother large areas of level or gently sloping ground under a ‘blanket’ of peat. Also known as ‘flow’ or ‘floe’, they are the most extensive type of mire fed entirely by rainfall and snowmelt rather than groundwater. As a result, blanket bogs are typically found in the wetter north and west of the UK from Devon to Shetland. In the far north, blanket bogs even extend down to sea level.
Where is it found?
About 1.5 million hectares of blanket bog – representing up to 15% of the total area worldwide – are found in the UK, the majority of which is in Scotland.
Why is it important?
Although blanket bog is naturally species-poor because of its acidity, both its name and appearance belies its considerable wildlife interest. Growing among the wispy strands of deergrass and cotton-grass can be found a variety of unusual plants and animals adapted to this specialised habitat, including bog rosemary, cranberry and insectivorous sundews.
Peaty pools separated by drier hummocks of heather, bilberry and crowberry are as common features as the sphagnum moss-dominated flats. Sphagnum mosses play a very important role in the creation of peat: they hold water in their spongy forms, providing essential nutrients to the soil and preventing the decay of dead plant material which eventually gets compressed to form peat.
Golden plover, dunlin and greenshank are some of the many bird species which nest on blanket bog, alongside a wide range of terrestrial and aquatic invertebrates. Approximately 40% of the UK’s large heath butterfly population is found on blanket bog.
Like other peatlands, blanket bogs also play another important role. Preserved by the constant waterlogging and acidic conditions, a wealth of fascinating evidence from the past, such as pollen, seeds, insects, wooden structures, organic artefacts and even human remains, have been found stored in chronological order in the layers of peat.
Is it threatened?
Peat is a precious resource that can take thousands of years to form and peat bogs are important habitats for a whole range of species from bog bush-crickets to hen harriers. However, our peat bogs have been overexploited by the commercial extraction of peat, particularly for horticulture, and have been irreparably damaged by drainage, afforestation and inappropriate management.
Peat is still growing on some active bogs, but the rate of formation is greatly exceeded by the rate of loss. Poorly managed grazing, intensive burning and acid rain all cause erosion, while peat-cutting exposes the underlying bedrock. The subsequent loss of sponge-like blanket bog causes flash flooding and erosion downstream.
How are The Wildlife Trusts helping?
The Wildlife Trusts are working to prevent further loss of our blanket bogs by looking after areas of blanket bog as nature reserves. We use traditional management techniques, such as grazing and burning, to maintain them, and we are restoring areas that have deteriorated.
Wildlife Trusts also provide advice and guidance for landowners and farmers on wildlife-friendly practices in these areas. By ensuring that the land surrounding our reserves is looked after sympathetically for wildlife, we can create A Living Landscape: a network of habitats and wildlife corridors across town and country, which are good for both wildlife and people.
What can I do to help?
- Most importantly, buy peat-free products for your garden, make your own compost and don't buy plants grown in peat.
- Take part in conservation measures on your land – ask your local Wildlife Trust for advice on grazing and management of blanket bog.
Across the UK several Wildlife Trusts are actively involved with the conservation and restoration of blanket bog habitats – you can support the work of your local Wildlife Trust by becoming a member.