Yanal Bog

Yanal Bog is a 1.6 hectare biological Site of Special Scientific Interest on the southern edge of the North [Somerset Levels], just north of the village of Sandford, North Somerset. It was notified as an SSSI in 1988.

Site description

Yanal Bog is a calcicolous lowland mire. Underlying the site are gravels and clay alluvium. Above this sits a layer of peat. This results in a high water table, creating a distinct domed landscape feature.

The plant communities of the mire are nationally rare in Britain, and support two species, Black Bog-rush and Blunt-flowered Rush, that have restricted distributions in south-west England, and a number of species that are localised in the North Somerset area. Surrounding the raised mire is a belt of grassland; although this is included within the SSSI, it is largely made up of common grass and herb species.
In the community in the western part of the mire, Blunt-flowered Rush, Purple Moor-grass and Carnation Sedge are abundant species, and this part of the mire is characterised by the presence of a number of species that favour base-rich conditions. Black Bog-rush is locally abundant along a wet drainage ditch in this western part of the site. In the eastern part of the mire Purple Moor-grass and Blunt-flowered Rush are again abundant, but the abundant sedge species are Lesser Pond-sedge and Greater Pond-sedge. Common Reed and Marsh Horsetail are also frequent. This part of the site supports plant species associated with more neutral conditions.
The site has a species-rich flora; species that occur here but are localised or confined to specialised habitats in North Somerset are Flea Sedge, Saw-wort, Meadow Thistle, Marsh Valerian, Dyer’s Greenweed, Marsh Arrowgrass, Southern Marsh-orchid, Fen Bedstraw, Devil’s-bit Scabious and Tawny Sedge and Tufted-sedge.