Jncc coastal Directories Project Region 11 The Western Approaches

Wooded combes in Devon and Somerset linked to sheltered
areas of heath or bracken provide habitat for two threatened
butterflies: the high brown fritillary Argynnis adippe and the
heath fritillary Mellicta athalia.  The region’s woodlands are
also important for a number of the UK’s rarest mammals
(see also 
section 5.13
), including the dormouse Muscardinus
avellanarius, which occurs in coastal coombe valley
woodland along the north Cornwall, north Devon, Somerset
and Avon coasts.  The red squirrel Sciurus vulgaris is rare
and declining in England and Wales; in this region it occurs
in woodlands in Cornwall and Gwent. 
Avon Gorge National Nature Reserve is a candidate SAC
as it represents a habitat type (ravine forest) rare in Europe.
The Wye Valley Woodlands are a candidate SAC as an
example of a varied beech forest. 
Region 11  Chapter 3  Terrestrial coastal habitats
40
The Valley of the Rocks, on the Exmoor coast, Devon, is typical of the vegetated cliffs of the western part of the region.  Region 11 is the most
important in the UK for rare cliff-growing plants.  Although the cliffs are exposed to strong winds and heavy salt spray, the frequent rain
and year-round mild temperatures allow many uncommon flowers to flourish, including some, such as the wild asparagus and peony, more
at home in the Mediterranean.  Photo: Peter Wakely, English Nature.

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3.1.1  Introduction
Geology and geological structure, together with past
environmental history (marine erosion and glacial processes)
determine cliff form (Jones & Lee 1994; Lee 1995).  The most
distinctive cliff types are consolidated (hard cliffs developed
from resistant bedrock) and unconsolidated (soft cliffs
developed in easily-eroded materials).  Soft cliffs are rare in
this region, where hard cliffs predominate (
Table 3.1.1
).
The region has a total cliff length of 407.5 km (
Table 3.1.1
;
Map 3.1.1
), which represents much of the region’s coast and
10% of the British resource; the region’s cliffs are therefore of
great importance in the national context.  There are also very
fine extents of cliff-top habitat (
Table 3.1.1
).  A total of 753 ha
of maritime grassland is recorded for the English coast in
the region (40% of the total extent in England (
Table 3.1.1
)).
Cliffs in the region exhibit good diversity in form
(
Table 3.1.2
).  
The soils and vegetation of cliffs and cliff-tops are closely
related to slope angle, soil type and salt spray deposition,
with much local variability possible with changing exposure
around headlands.  The major natural and semi-natural cliff
and cliff-top habitats in Great Britain are bare ground,
spray-zone lichen-covered rock, rock crevice, cliff-ledge,
seabird colony, perched saltmarsh, maritime grassland and
maritime heath.  Very sheltered cliffs and cliff-top sectors
that receive little salt spray input are not here treated as
coastal habitats.  Soft cliffs on sheltered coasts can develop
undercliff vegetation of woodland, scrub, tall herb and rank
grassland, often very close to the sea.  The full extent of cliff-
top habitat in the region has not been surveyed but the
exposure of the coast to very strong winds and heavy spray
deposition probably allows mainly maritime grassland to
develop, with most of this restricted to hard cliffs.  
The scenic contribution of cliffs within the region is
outstanding, with tall and lengthy hard cliffs cut in varied
sedimentary, igneous and metamorphic rocks.  This scenic
value is recognised by 326 km of largely cliffed coast
fronting Areas of Outstanding Natural Beauty in the Isles of
3.1  Cliffs and cliff-top vegetation
41
3.1  Cliffs and cliff-top vegetation
Dr T.C.D. Dargie
Region 10
Region 12
5°W
Cliff
Map 3.1.1  
Sea cliffs.  Source: JNCC Coastal Database and
OS Landranger maps.  © Crown copyright.
Table 3.1.1  
Cliff and maritime cliff grassland resource
a
in context
Soft cliffs
All cliffs
Maritime cliff grassland
Area
Total length
% of total in 
Total length
% of total in
Area (ha)
% of total in
(km)
Region 11
(km)
Region 11
Region 11
Isles of Scilly
-
-
29
7
70
?
Cornwall
2
?
199
49
502
?
Devon
2
?
95
23
137
?
Somerset
1
?
29
7
17
?
Avon
1
?
20
5
9
?
Gloucestereshire
-
-
8
2
18
?
Mid-Glamorgan
?
?
9
2
?
?
South Glamorgan
?
?
21
5
?
?
Region 11
?
-
408
-
?
?
England
256
2
1,165
32
1,895
40
Wales
?
?
523
6
?
?
West Coast*
?
?
2,272
18
?
?
GB*
?
?
4,059
10
?
?
Source: Pye & French (1993).  Key: *excluding the Isle of Man; 
a
all figures have been rounded to the nearest whole number; ? = unknown.
Scilly, Cornwall, north Devon and Somerset (Quantock
Hills) and 38 km fronting Exmoor National Park, with
further recognition of 259 km as lengths of Heritage Coast
(Gubbay 1988; Heritage Coast Forum 1993). Large stretches
of cliff, especially in Cornwall and Devon, are also
designated as Sites of Special Scientific Interest (SSSIs).
3.1.2  Important locations and species
Soft cliffs are rare in the region and are restricted to very
short sectors in Cornwall, north Devon, Somerset and Avon.
Hard cliffs are much more extensive, with especially fine
lengths of tall (50-100 m) near-vertical cliffs with relatively
flat tops developed in Cornwall in igneous and
metamorphic rocks, including the famous headlands of the
Lizard, Land’s End and Cape Cornwall.  Taller, stepped
cliffs are developed in sedimentary rocks between Boscastle
and Wanson in Cornwall, up to 160 m height and
descending from up to 400 m inland.  A notable additional
feature of cliffs in Cornwall is a gradation to climbing sand

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