Jncc coastal Directories Project Region 11 The Western Approaches

From Boscastle north to Hartland Point, the shore is
mostly of rock with occasional small sandy coves, larger
expanses of sand occurring at Widemouth and north of
Bude.  At Duckpool near the Devon border, the lower shore
has exceptionally fine colonies of the reef-building
honeycomb tube-worm Sabellaria alveolata.  These colonies
are considered to be the finest in Britain (Cunningham et al.
1984), the area being considered by Powell et al. (1978) to be
of primary marine biological importance.  The sea bed in
this area consists of gently sloping bedrock with boulders at
some sites, rock surfaces having an even covering of sand
(Hiscock 1981).  In depths down to 26 m, these habitats are
dominated by algae, particularly the brown seaweeds
Dictyota dichotoma and Dictyopteris membranacea and various
foliose red species.  Vertical and upward-facing rock surfaces
are dominated by bryozoans, sea squirts and sponges, with
erect sponges such as Raspailia hispida being common.
Hartland Point to Foreland Point (including Lundy)
The coastline of north Devon comprises high cliffs
punctuated by the broad, sandy beaches of Bideford Bay.
Little published information is available for many areas
within this section, though it was the seashore life of north
Devon that enthused the well-known nineteenth century
naturalists Philip Henry Gosse and Charles Kingsley.
Sublittoral communities dominated by mussels Mytilus
edulis are present in the Clovelly area and also at Morte
Point.  These communities appear to be different from those
of north-east Cornwall or the north Devon coast east of Bull
Point (Hiscock 1981), which may indicate the presence of a
biogeographical boundary.  The Taw-Torridge Estuary
complex is a broad sedimentary estuary extending some
distance inland.  Marine habitats and communities within
the estuary have been surveyed for the Nature Conservancy
Council (Little 1989, in Davies in prep. a), though
communities found had a low species richness and
abundance.
The island of Lundy lies 18 km off the north Devon coast
and measures just 5 km by 1.25 km, with a 15 km coastline
ranging from very exposed to very sheltered from wave
action.  It has been proposed as a possible SAC for its reefs.
Most of the island is formed of granite, with inaccessible
shores at the base of steep cliffs, though the south-east
corner is of more friable slate, which supports rich intertidal
communities.  The island is of great marine biological
importance: it became Britain’s first Voluntary Marine
Nature Reserve in 1973 and the country’s first statutory
Marine Nature Reserve in 1986.  The waters around the
island now constitute a Sensitive Marine Area (English
Nature 1994a), on account of the outstanding variety of its
nearshore habitats and communities (
Table 4.2.2
).  Owing to
the influence of a number of physical conditions (e.g. strong
tidal currents, variable wave exposure, juxtaposition of
various coastal and oceanic water masses), several of these
are habitats and communities that are rarely encountered
elsewhere in Great Britain.  West-facing shores are classified
as being very exposed, with rich lichen communities, below
4.2  The sea bed
71
Table 4.2.2  
Marine subtidal communities of international/national importance around Lundy
Importance
Notes
International
Mostly unbroken Within each ecological depth zone, widely different communities are present at different locations around the island.
rock
The community type is related to the degree of exposure to wave action and tidal streams, and to other environmental
factors, such as siltation, influenced by exposure.  Many of the animal communities, particularly on the east coast,
include colourful Mediterranean-Atlantic species in abundance and are of high aesthetic appeal.  The range of
communities, their richness and the presence of many Mediterranean-Atlantic species are outstanding in the context
of north-east Atlantic sublittoral ecosystems.
National
Stable boulders
Algal communities on sublittoral boulders are often distinctly different from those of nearby rock, although it is not
clear whether this results from the habitat or natural variability.  Animal communities on boulders are distinctly
different from those of nearby rock and are comparatively impoverished.  The areas of boulder substratum around
Lundy are very extensive and include wave-sheltered areas where distinctive communities not observed or rarely
observed elsewhere in south-west Britain are present.
Muddy gravel
The extensive areas off the east coast are colonised by a distinctive fauna rarely encountered elsewhere nearshore in
south-west Britain.  The communities correspond to the ‘Boreal offshore muddy-gravel association’ described by
Holme (1966) for areas off Plymouth.  Their assessment as being of national importance here is made because this
type of community was not described by Jones (1950) and therefore appears to be unusual, and because of the
convenience for study in shallow water at Lundy.
Mud and muddy These extensive areas nearshore off the east coast support a rich community characterised by several conspicuous
sand
species including Amphiura filiformis, Goneplax rhomboides and Cepola rubescens.  The community has been assigned to
the Amphiura filiformis community of Thorson (1957) and is probably similar to the ‘Boreal offshore muddy-sand
association’ described by Holme (1966) for the English Channel.  This appears to be an unusual habitat for the Bristol
Channel, and is particularly interesting because of the presence of Cepola rubescens, which upgrades the rating to one
of national importance.
Cliffs
The extensive sublittoral cliffs present at Gannets Rock Pinnacle and Seals Rock provide good examples of semi-
exposed and exposed cliff faunas respectively.  Smaller areas of sublittoral cliffs are present on other parts of the
coasts and include communities different from those of surrounding upward-facing or broken rock.
Wrecks
The community present on the wreck of the M.V. Robert is extremely well-developed as a distinctly different
community from those of rocks in similar conditions and can be considered a ‘classic’ wreck community.  The Robert
is one of very few intact wrecks present around the coast and should remain intact for several years, although it must
be considered a transitory feature.  Other wrecks around Lundy are mostly broken-up and the communities present
differ little from adjacent rock communities.
Sources: Hiscock (1983); English Nature (1994b)

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