Yanal Bog () is a 1.6
hectare
The hectare (; SI symbol: ha) is a non-SI metric unit of area equal to a square with 100- metre sides (1 hm2), or 10,000 m2, and is primarily used in the measurement of land. There are 100 hectares in one square kilometre. An acre is ...
biological Site of Special Scientific Interest
A Site of Special Scientific Interest (SSSI) in Great Britain or an Area of Special Scientific Interest (ASSI) in the Isle of Man and Northern Ireland is a conservation designation denoting a protected area in the United Kingdom and Isle of ...
on the southern edge of the
North Somerset Levels
The North Somerset Levels is a coastal plain, an expanse of low-lying flat ground, which occupies an area between Weston-super-Mare and Bristol in North Somerset, England. The River Banwell, River Kenn, River Yeo and Land Yeo are the three prin ...
, just north of the village of
Sandford,
North Somerset
North Somerset is a unitary district in Somerset, South West England. Whilst its area covers part of the ceremonial county of Somerset, it is administered independently of the non-metropolitan county. Its administrative headquarters is in the ...
. 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
Peat (), also known as turf (), is an accumulation of partially decayed vegetation or organic matter. It is unique to natural areas called peatlands, bogs, mires, moors, or muskegs. The peatland ecosystem covers and is the most efficient ...
. This results in a high
water table
The water table is the upper surface of the zone of saturation. The zone of saturation is where the pores and fractures of the ground are saturated with water. It can also be simply explained as the depth below which the ground is saturated.
T ...
, creating a distinct domed landscape feature.
Biological interest
The
plant communities
A plant community is a collection or association of plant species within a designated geographical unit, which forms a relatively uniform patch, distinguishable from neighboring patches of different vegetation types. The components of each plant ...
of the mire are nationally rare in Britain, and support two species, Black Bog-rush (''
'') and Blunt-flowered Rush (''
Juncus subnodulosus''), 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 (''
Molinia caerulea
''Molinia caerulea'', known by the common name purple moor-grass, is a species of grass that is native to Europe, west Asia, and north Africa. It grows in locations from the lowlands up to in the Alps. Like most grasses, it grows best in acid s ...
'') and Carnation Sedge (''
Carex panicea'') are abundant species, and this part of the mire is characterised by the presence of a number of species that favour
base-rich
In ecology, base-richness is the level of Base (chemistry), chemical bases in water or soil, such as calcium or magnesium ions. Many organisms prefer base-rich environments. Chemical bases are alkalis, hence base-rich environments are either pH, ...
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 (''
Carex acutiformis
''Carex acutiformis'', the lesser pond-sedge, is a species of sedge.
Description
It grows up to tall, with leaves up to long and wide.
Ecology
It is native to parts of northern and western Europe, where it grows in moist spots in a number of ...
'') and Greater Pond-sedge (''
Carex riparia
''Carex riparia'', the greater pond sedge, is a species of sedge found across Europe and Asia. It grows in a variety of wet habitats, and can be a dominant species in some swamps. It is Britain's largest ''Carex'', growing up to tall, with glau ...
''). Common Reed (''
Phragmites australis
''Phragmites australis'', known as the common reed, is a species of plant. It is a broadly distributed wetland grass that can grow up to tall.
Description
''Phragmites australis'' commonly forms extensive stands (known as reed beds), which may ...
'') and Marsh Horsetail (''
Equisetum palustre'') 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 (''
Carex pulicaris''), Saw-wort (''
Serratula tinctoria''), Meadow Thistle (''
Cirsium dissectum
''Cirsium dissectum'', also known as meadow thistle, is an erect perennial herb. It is found in England, Wales, Ireland, France, the Netherlands, Germany, Italy, Spain, Hungary, Norway, etc. It is found in fens and less acidic peat bogs i.e. it ...
''), Marsh Valerian (''
Valeriana dioica
''Valeriana dioica'', the marsh valerian, is a species of flowering plant in the genus ''Valeriana
''Valeriana'' is a genus of flowering plants in the family Caprifoliaceae, members of which may by commonly known as valerians. It contains many ...
''), Dyer’s Greenweed (''
Genista tinctoria''), Marsh Arrowgrass (''
Triglochin palustris
''Triglochin palustris'' or marsh arrowgrass is a species of flowering plant in the arrowgrass family Juncaginaceae. It is found in damp grassland usually on calcareous soils, fens and meadows. The species epithet ''palustris'' is Latin for "of ...
''), Southern Marsh-orchid (''
Dactylorhiza praetermissa
''Dactylorhiza praetermissa'', the southern marsh orchid or leopard marsh orchid, is a commonly occurring species of European orchid.
Description
''Dactylorhiza praetermissa'' grows to tall, with leaves generally unspotted. The flowers, appea ...
''), Fen Bedstraw (''
Galium uliginosum''), Devil’s-bit Scabious (''
Succisa pratensis'') and Tawny Sedge (''
Carex hostiana'') and Tufted-sedge (''
Carex elata
''Carex elata'', tufted sedge, is a species in the genus ''Carex'', native to all of Europe, the Atlas Mountains of Africa, Turkey, Iran and Central Asia. It prefers to grow with its roots in water. Its cultivar 'Aurea' has gained the Royal Horti ...
'').
See also
*
Max Bog, a similar SSSI to the southwest of Yanal Bog
Sources
English Nature citation sheet for the site (accessed 15 July 2006)
External links
English Nature (SSSI information)Site boundary at "Nature on the Map" website
{{SSSIs Avon biological
Bogs of England
Sites of Special Scientific Interest in North Somerset
Sites of Special Scientific Interest notified in 1988