Jncc coastal Directories Project Region 11 The Western Approaches

Region 11  Chapter 1  Overview
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Regi
on 10
Regi
on
12
5°W
Cam
el
Fal
Helford
Tor
ri
dg
e
Taw
Pa
rrett
Se
ve
rn
W
ye
Us
k
Taf
f
El
y
Avon
Axe
Brue
Truro
Falmouth
Helston
Penzance
St Ives
Newquay
Trevose Head
Kelsey Head
Polzeath
Padstow
Wadebridge
Tintagel
Bude
Clovelly
Braunton
Lundy
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11
10
7
8
9
6
5
4
2
1
3
Ilfracombe
Hartland Point
Bristol Channel
Lynton
Bideford
Minehead
Bridgwater
Burnham-on-Sea
Weston-super-Mare
Clevedon
Bristol
Gloucester
Chepstow
Newport
Cardiff
Penarth
Barry
Severn Estuary
Porthcawl
Kenfig
Avonmouth
Barnstaple
Lizard Point
Mount
’s Bay
Land’s End
Tresco
St Martin’s
St Mary’s
St Agnes
Bryher
St Agnes Head
Key to local authorities
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3
4
5
6
7
8
9
10
11
12 Bridgend
Vale of Glamorgan
Cardiff
Newport
Monmouthshire
Gloucestershire
South Gloucestershire
City and County of Bristol
North West Somerset
Somerset
Devon
Cornwall
Map 1.2.1
Rivers, major towns and other coastal locations in the region
Region 10
Region 12
5°W
Map 1.2.2
National grid 10 km x 10 km squares included as
‘coastal’ for this region
Close to the shore the sea bed shelves steeply to about
60 m and then slopes gently to the edge of the Continental
shelf.  The sea bed is covered with a thin veneer of mobile
sediments, except in a few deeper ‘valleys’, which have
become infilled with recent (Holocene) sediments.  The most
important of these valleys is in the Severn and is obliterated
by sand banks in its upper reaches but remains a distinct
feature westwards to the south-west of Gower.  Region 11
supports one of the most diverse ranges of communities of
sea-bed plants and animals in Great Britain.  This is a
reflection of the range and type of substratum, the degree of
variation in exposure, particularly around islands
(especially the Isles of Scilly and Lundy Island), and the
warming influence of the Gulf Stream.  Many of the rarer
species are Mediterranean-Atlantic in their distribution and
include sea fans, cup corals and soft corals that in Great
Britain are confined to the south-west.  The coastal
nearshore area around the region is among the most diverse
such areas in Europe and includes 39 rare and 31 scarce
marine benthic species.  The coastal waters also have some
of the richest and most diverse populations of non-exploited
fish, with 111 of the 336 species found around the UK
recorded in the Severn Estuary alone, an above average
regional total and much higher than the 48 found along
England’s North Sea coast.
Grey seals are the only seal species present in the area;
whilst not numerous, they produce 0.5% of the pups born in
Great Britain.  The Isles of Scilly and Lundy are the major
sites, with small colonies scattered along the Cornish coast.
Elsewhere in the region they are virtually absent.
Leatherback Dermochelys coriacea and loggerhead Caretta
caretta turtles have been recorded relatively frequently in
this region.  Most leatherbacks are sighted swimming at sea
west of Land’s End, and the loggerheads recorded were
found stranded in Mount’s Bay, Cornwall.  The south-west
approaches to the English Channel are richer in cetaceans
than any other part of southern Britain, with seventeen
species recorded, nine of them either present throughout the
year or recorded annually as seasonal visitors to the region.
Cetacean species richness and abundance declines markedly
from west to east in the Bristol Channel.

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The Isles of Scilly, Lundy and to a lesser extent Flat
Holm and Steep Holm in the Bristol Channel include a wide
variety of rare plants and animals, on the islands, in the
surrounding sea and on the near-shore sea-bed.  Some
species or sub-species, such as the Lundy cabbage Coincya
wrightii, are extremely rare or unique to the islands.  This
combination of terrestrial species and offshore marine
conservation interest represents an extremely rich
environment.
Estuarine shores
The estuaries in the region represent more than 12% of the
British resource and include one of the ten most extensive
estuary systems in the UK: the inner Bristol Channel, the
Severn Estuary and its several tributary rivers including the
Taff/Ely.  Taken together with Bridgwater Bay, the complex
is important at a European scale.  The whole of the Severn
Estuary is a Special Protection Area and Ramsar Site and has
been identified as a candidate Special Area of Conservation
(SAC) under the EC Habitats & Species Directive.  The
Severn Estuary and Bridgwater Bay (also a Ramsar Site)
together hold around 3.5% of the British wintering
waterfowl population, a highly significant proportion for a
single estuarine complex.  The area is also important
because it usually remains frost free during the winter, and
in periods of hard weather elsewhere in the UK it may
increase in importance to waterfowl, with major influxes of
species such as teal and wigeon.  Extensive (up to 6 km
wide at low spring tides) tidal mudflats also occur at
Bridgwater Bay.  The region also includes Falmouth Bay
(south Cornwall), one of Britain’s best and largest examples
of a ria, an estuary type well represented further east on the
south coast, particularly in Region 10.  The River Camel is
the only significant example of a ria on the north coast.  
There has been extensive enclosure for agriculture since
Roman times around all the main estuaries, particularly
those associated with the Severn.  Despite the extent of
saltmarsh lost to enclosure in the Severn Estuary, which Pye
& French (1993) estimate to have been 84,000 ha, there is still
a significant area (1,400 ha including Bridgwater Bay)
remaining - nearly 4% of the Great Britain resource.
Although more than 40% of the marsh is dominated by
common cord-grass Spartina anglica, there is an extensive
sequence of more mature marshes, including upper marsh
and transitions to brackish swamp with common reed
Phragmites australis.  Some of these upper marshes include a
number of coastal species typically confined to salt or
brackish marshes covered infrequently by the tides, such as
the rare slender hare’s ear Bupleurum tenuissimum and sea
barley Hordeum marinum.  Where it is found elsewhere in
south-east England it occurs uncharacteristically on sea
walls and coastal grazing marsh.  
In several areas of former saltmarsh and swamp,
secondary habitats, managed for low-intensity agriculture
over many hundreds of years, have developed their own
man-modified wildlife habitats.  These include two of the
most extensive areas of coastal wet grassland in Great
Britain, the Somerset Levels, and the Caldicot and
Wentlooge Levels in south Wales, which are derived from
former tidal lands (enclosed from Roman times onwards).
Their landscape consists of small meadows interspersed
with narrow drainage ditches, and large areas of the
Somerset Levels may be flooded in winter.  Having
remained largely free from intensive agricultural use in
recent years, they have maintained considerable
conservation interest.  Of special note are wintering
waterfowl, and breeding waders, for which the Somerset
Levels support one of the five biggest populations on
lowland grassland in southern Britain.  Some of the
unimproved grasslands and the drainage ditches have a rich
variety of plants and notable invertebrate animals, and
where there are gradations from fresh to brackish water
these assemblages may be particularly rich.
Non-estuarine shores
Sea cliffs abound in the region, making up a high proportion
of the region’s coastline and 10% of the British resource in
terms of its length.  From the south-west to the north-east
they occur as progressively younger and softer rocks, with
Minehead providing a geographical divide between the
more rugged coasts of Cornwall, north Devon and Somerset
and those adjacent to the Bristol Channel and the Severn
Estuary.  The region’s cliffs are generally 50-100 m high,
rising to more than 100 m around the coast of Lundy Island
and in parts of Cornwall, and to 150 m at Embury Beacon
south of Hartland Point.  Steeper rugged sections of cliff
occupy the majority of the coast of south and north
Cornwall to Somerset.  These include the Lizard, Land’s
End and the north-west facing cliffs of north Cornwall,
north Devon and the west facing section of Somerset
including the coast of the Exmoor National Park, which
adjoins the coast near Lynton.  Generally the geological
strata are a (sometimes very complex) mixture of calcareous
and non-calcareous rocks.  Superimposed on the effects of
the underlying geology, slope and aspect is the influence of
exposure and salt spray, which helps to create an almost
complete sequence of sea-cliff plant communities.  These
include extensive exposed maritime communities, including
spray zone crevice communities with golden samphire Inula
crithmoides, grassland and heath, the latter with examples of
vegetation dominated by the rare Cornish heath Erica
vagans, calcareous cliff and cliff-top vegetation and coastal
woodlands in the valleys.  Occasionally on the exposed
Cornish coast, where the effects of wind and salt spray are
extreme (such as at the Dizzard), there may be stunted
woodlands in which the height of individual trees - even
mature oaks - is restricted to a few metres.  There are
significant stretches of soft cliffs, with communities ranging
from tall grassland/scrub through to open ephemeral
communities on unstable ground, though these are much
less frequent than on the coasts of Regions 9 and 10 to the
east.  Some of the best examples of the Atlantic cliff
vegetation type identified in the EC Habitats & Species
Directive, representing the southern element of the
community type, occur in this region.  In addition to the
Lizard, an extensive stretch of coast between Tintagel,
Marsland and Clovelly is a candidate SAC.
On this region’s cliffs occur six of the nine nationally rare
(e.g. wild asparagus Asparagus officinalis subsp. prostratus)
and three of the four nationally scarce (e.g. thyme
broomrape Orobanche alba) plants that are virtually restricted
to sea cliffs in Great Britain.  These and the other rare
species occurring on cliffs (although not restricted to them)
in the region (e.g. wild leek Allium ampeloprasum) make the
cliff sections of this region’s coast amongst the most
significant in Great Britain.  Pride of place from a botanical
1.2  Introduction to the region
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