BIODIVERSITY OF WESTERN MENDIP
SITE: CHEDDAR GORGE
Sub-site: Cheddar Cliffs (and Bubwith Acres)
Cheddar Gorge supports a complex mosaic of valuable semi-natural
habitats, which between them are home to a wide range of species,
many of which are rare. Limestone grasslands on the gorge slopes
are rich in calcicolous (lime-loving) plants, which thrive in the
thin dry soils. On slopes with a southern to western aspect these
include sheep's-fescue (Festuca ovina), salad burnet (Sanguisorba
minor), common bird's-foot-trefoil (Lotus corniculatus),
wild thyme (Thymus polytrichus) and common rock-rose (Helianthemum
nummularium). Cooler and wetter aspects support an equally
rich sward, but the range of species found here includes flea sedge
(Carex pulicaris), betony (Stachys officinalis)
and lady's bedstraw (Galium veru). Rough grassland with
a history of scrub invasion favours coarse species e.g. upright
brome (Bromopsis erecta), wood sage (Teucrium scorodonia)
and wild marjoram (Origanum vulgare). These grasslands
are of outstanding importance for insects and other invertebrates,
and in summer many different species of butterfly are abundant
on open sunny slopes.
Limestone crags, rocky outcrops and cliff faces support populations
of some of the specialities of the gorge, including the rare and
protected Cheddar pink (Dianthus gratianopolitanus), slender
bedstraw (Galium pumilum) and lesser meadow-rue (Thalictrum
minus), and peregrine falcons (Falco peregrinus)
can sometimes be seen soaring through the gorge. Scree slopes are
frequent below the cliffs and in places support good populations
of ferns, including maidenhair spleenwort (Asplenium trichomanes),
rustyback (Ceterach officinarum) and the uncommon limestone
fern (Gymnocarpium robertianum) and mats of mosses, including Neckera
crispa with its shiny, wrinkled leaves and robust, complanate
habit. Madder (Rubia peregrina) can often be found scrambling
through scrub and over rocks. This normally coastal plant is common
in the Cheddar area.
Mixed scrub is an important habitat within the gorge, and is characterised
by ash (Fraxinus excelsior), yew (Taxus baccata),
hazel (Corylus avellana) and hawthorn (Crataegus monogyna).
It also supports whitebeams (Sorbusspecies), including
two rare British endemics. In places, mature ash-oak-hazel woodland
has developed, and sanicle (Sanicula europaea), dog's-mercury
(Mercurialis perennis) and broad-leaved helleborine
(Epipactis helleborine) can all be found on the woodland
Plateau soils are deeper and more nutrient-rich, and have an interesting
mosaic of flower-rich unimproved grassland within a patchwork of
thorn scrub. In places, the large anthills constructed by yellow
meadow-ant (Lasius flavus) are prominent, showing holes
where green woodpeckers (Picus viridis) have been feeding
on the ants inside. In spring, the uncommon green-winged orchid
(Orchis morio) is a distinctive feature of these grasslands.
Windblown loessic soils have a more neutral-acidic character, and
support pignut (Conopodium majus), sweet vernal-grass
(Anthoxanthum odoratum), common knapweed (Centaurea
nigra) and harebell (Campanula rotundifolia). At
Bubwith Acres Nature Reserve, these species co-exist with species-rich
calcicolous grassland where underlying limestone reaches the surface,
and waxcap fungi (Hygrocybe species) are abundant in the
Elsewhere, there are small patches of limestone heath, an uncommon
and highly distinctive Mendip habitat. Calcifuges (lime-hating
species) including ling (Calluna vulgaris) and heath bedstraw
(Galium saxatile) co-exist with the typical limestone
Caves within the Cheddar Gorge complex are important for roosting
and hibernating bat species, including significant numbers of the
nationally rare greater horseshoe bat (Rhinolophus ferrumequinum).
Sub-site: Velvet Bottom
The reserve is dominated by extensive areas of rough neutral grassland.
Lead contamination of the lower ground over the centuries has prevented
tree and scrub growth, and the grassland is relatively species-poor.
High levels of lead are toxic to most plants, but over a long period
of time, a small but select group has colonised the lead slag heaps
that are found in the middle of the reserve. In early spring, mats
of common whitlowgrass (Erophila verna) a tiny, white-flowered
crucifer, are abundant on dry banks of bare slag, along with herb Robert
(Geranium robertianum), and occasionally, spring sandwort
(Minuartia verna) which is a rare plant in southern England,
and which, on Mendip, is nearly always associated with old lead
Damper ground associated with old settling beds, buddle pits and
other depressions are defined by the presence of cuckooflower (Cardamine
pratensis), wild angelica (Angelica sylvestris),
marsh thistle (Cirsium palustre) and other typical species
of marshy grassland.
A more varied vegetation is present on the edges of the reserve,
where acidic soils support the uncommon meadow saffron (Colchicum
autumnale) the attractive flowers of which can be found in
September among the bracken (Pteridium aquilinum). Devil's-bit
scabious (Succisa pratensis), ling and other wildflowers
attract many insects, especially butterflies and grasshoppers,
and dry grassland supports large populations of Adders (Vipera
berus) and common lizard (Lacerta vivipara) which
may be often seen basking early or late in the day.
Short, rabbit-cropped limestone turf occurs in a few places, and
a wide diversity of typical herbs and grasses are present, including
carline thistle (Carlina vulgaris), and common spotted orchid
(Dactylorhiza fuchsii), which attract many butterflies
on warm days. Spring cinquefoil (Potentilla neumanniana)
is also found in a few places.
Sub-site: Ubley Warren
The legacy of centuries of opencast lead mining
is evident in the uneven gruffy ground and worked-out mineral rakes
at this site, and it has been designated as a Site of Special Scientific
Interest on account of the intricate and extensive juxtaposition
of acidic, lime-loving and lead-tolerant vegetation.
The rakes (characterised by limestone cliffs and exposures within
the areas of mining disturbance) are a dominant feature of the
reserve, and support important communities of mosses, liverworts,
lichens and ferns, some of which are rare. Sheltered and humid
conditions within some of the rakes mimic woodland conditions,
and a number of typical limestone woodland species can be found.
Acid grassland growing over aeolian loess soils is typified by
such plant species as common bent (Agrostis capillaris)
and heath bedstraw. Large grassland mosses are a distinctive feature
of this sward, and include Hylocomium splendens and Climacium
dendroides. Heathland vegetation is also abundant, supporting
gorse (Ulex europaeus), western gorse (U. galli),
ling, purple moor-grass (Molinia caerulea), bilberry (Vaccinium
myrtillus) and heath spotted orchid (Dactylorhiza maculata).
Many of the rare plants at Ubley Warren are associated with the
worked-out mineral rakes and limestone outcrops, including the
nationally scarce soft-leaved sedge (Carex montana) which
is quite frequent, and often grows in association with early purple
orchid (Orchis mascula). Hutchinsia (Hornungia petraea)
and brittle bladder-fern (Cystopteris fragilis) also favour
limestone. Typically, the shallow base-rich soils have developed
a rich limestone flora, which also supports common spotted orchid
and bee orchid (Ophrys apifera).
Where lead-rich soil is present, the nationally scarce spring
sandwort can be found.
Ubley Warren is an important site for reptiles, with slow-worm
(Anguis fragilis), adders and common lizards all present.
Sub-site: Black Rock
Steep, south-facing slopes support short herb-rich limestone grassland
over thin soils. A very high number of plant and invertebrate species
are present in this turf, and many of the plants are very diminutive.
Sheep's-fescue, wild thyme and quaking-grass (Briza media)
are some of the characteristic species, and more notably, spring
cinquefoil can be seen flowering in the spring. Common rock-rose,
a prostrate sub-shrub with showy yellow flowers in summer, thrives
on these warm slopes. Pollinating insects and nectar-feeders are
abundant on warm days, and include such species as the spring-flying
brimstone (Gonepteryx rhamni), common blue (Polyommatus
icarus), and cinnabar moth (Tyria jacobaea).
Semi-natural woodland clothes the steep and rocky valley slopes
close to the top of Cheddar Gorge. This is the typical ash-hazel
woodland of the local area. Many ferns and lower plants thrive
in the shady and humid conditions, and nearby dry limestone walls
are draped with mats of various calcicolous mosses and liverworts.
Mosses such as Neckera complanata and Ctenidium molluscum form
dense mats, and are well adapted to alternating cycles of dehydration
and irrigation. These walls, and the stonework of the disused limestone
kiln in the quarry also provide excellent anchorage for several
diminutive ferns, such as rustyback, wall-rue (Asplenium ruta-muraria),
and maidenhair spleenwort.
Birds are well represented in the nature reserve, and it is possible
to hear the distinctive 'cronk' of ravens (Corvus corax),
and see sparrowhawks (Accipiter nisus) and a variety of
finches and warblers. The woodlands also support badgers Meles
meles, foraging bats, and, where honeysuckle (Lonicera
periclymenum) is present in the woodland and scrub understorey,
the uncommon dormouse (Muscardinus avellanarius).
Sub-site: Long Wood
Long Wood has been woodland since possibly as early as the thirteenth
century, and it now supports many plants and animals that are usually
restricted to ancient woodland sites. Much of the wood has been
traditionally managed as coppice with standards, and evidence of
this can be seen close to the path in the valley bottom.
Ash and pedunculate oak (Quercus robur) are the main
canopy trees, and stands of beech (Fagus sylvatica) were
planted in the 1950s. Below, the understorey is characterised mainly
by hazel, field maple (Acer campestre), and in wetter
ground, grey willow (Salix cinerea). Fallen wood provides
ideal habitat for dead-wood invertebrates and fungi.
In spring, woodland herbs are at their best in Long Wood. Ramsons
(Allium ursinum) forms dense white garlic-scented carpets
near the stream, with yellow-flowered carpets of opposite-leaved
golden-saxifrage (Chrysosplenium oppositifolium) in the
wettest places. Large, sharp-edged tussocks of tufted hair-grass
(Deschampsia cespitosa) also thrive in this wet, clayey
ground, and in summer, send up tall, elegant infloresences. Higher
ground favours bluebell (Hyacinthoides non-scripta), wood
anemone (Anemone nemorosa) and more uncommonly, herb Paris
(Paris quadrifolia) and the curious parasitic toothwort
Blackmoor's long history of lead mining has created a rich mosaic
of valuable wildlife habitats. Bare and sparsely vegetated slag
heaps contain high levels of toxic heavy metals, especially lead,
zinc and cadmium, and very low levels of plant nutrients. Slow
colonisation of the heaps by a specialised community of metalliferous
specialists has taken place over time, and a low-growing mat of
lichens, mosses, and tolerant vascular plants can be found. Alpine
penny-cress (Thlaspi caerulescens) is a rare plant which,
in Britain, is almost confined to sites rich in lead or zinc. Other
unusual plants include sea campion (Silene uniflora).
Mats of the tiny white-flowered common whitlowgrass flower in early
spring on bare ground. The slag heaps (and large chunks of metalliferous
slag) also support a diverse lower plant and lichen community,
which includes small lichens of the Cladonia genus and
several species that are normally found on siliceous rocks in montane
areas (e.g. the small moss Grimmia donniana and the greenish-yellow
crustose lichen Rhizocarpon geographicum).
Gruffy ground (uneven and mostly long grassland resulting from
opencast lead mining) supports a wide range of plant species, but
few are constant and abundant. Several large carpet-forming mosses
are however prominent, including the red-stemmed Hylocomium
splendens and Pseudoscleropodium purum.
The worked-out rakes are associated with a rich lime-loving flora
typical of limestone grassland. Several diminutive mosses and ferns
are very characteristic of these outcrops, especially wall-rue Asplenium
ruta-muraria and the mosses Fissidens cristatus and Schistidium
Open water, an unusual habitat in this part of the Mendip Hills,
is found at Blackmoor in the form of several old ponds lying over
the Avon Group mudstones. These ponds, and their associated wetlands,
support distinctive flora and fauna, and contribute to the reserve's
total of four species of amphibian, and four common species of
reptile, including grass snake (Natrix natrix). Deeper
water is home to a number of aquatic plants, e.g. Mare's-tail (Hippuris
vulgaris), amphibious bistort (Persicaria amphibia)
and water-starwort (Callitriche species). Species of
the wetland edge include Marsh-marigold (Caltha palustris),
brown sedge (Carex disticha) and water-plantain (Alisma
plantago-aquatica). The pools are also important for dragonflies
and damselflies and a wide range of other invertebrate fauna.
Limestone heath can also be found on higher ground on the reserve.
This nationally rare habitat type supports a majority of calcifugous
(lime-hating) plants growing alongside some typical calcicolous
(lime-loving) species in shallow soil overlying limestone rock.
Locally, rainwater has leached carbonate ions away from the root-zone
in the surface horizons, allowing shallow-rooted acid-loving plants
to grow. At Blackmoor, such communities are typified by ericaceous
shrubs and herbs including ling, western gorse, tormentil (Potentilla
erecta) and purple moor-grass.
With such a wide range of habitats present at Blackmoor, many
birds are resident or frequent visitors, including blackcap (Sylvia
atricapilla), swallow (Hirundo rustica) and yellowhammer
Sub-site: GB Gruffy Field
Very uneven ground in the southern half of this reserve is partly
due to the presence of a number of caves and swallets in the underlying
limestone, as well as being a legacy of past lead mining in the
area. Lead-rich waste is present, and whilst poorly vegetated,
it supports both Spring Sandwort and alpine penny-cress, which
are characteristic of old lead-workings in the Charterhouse area.
The vegetation is very species-rich, and forms an intricate mosaic
of both acid-loving and calcicolous species, especially where limestone
rock forms low outcrops. Some of the more typical species include
common bird's-foot-trefoil, fairy flax (Linum catharticum),
tormentil, common sorrel (Rumex acetosa) and wild thyme.
The nationally scarce dwarf mouse-ear (Cerastium pumilum)
and the local hairy rock-cress (Arabis hirsuta) are diminutive
herbs that are associated with calcareous bare ground or short
grassland in this part of the reserve.
Cave entrances and larger sinkholes provide humid and sheltered
conditions which are ideal for a wide range of ferns, including
soft shield-fern (Polystichum setiferum), brittle bladder-fern
and broad buckler-fern (Dryopteris dilatata).
Loessic soils over shale in the northern half of the site support
damp, species-rich neutral-acidic pasture, with some stands of
bracken. Rushes indicate impeded drainage in places, with soft-rush
(Juncus effusus) being particularly abundant. Common spike-rush
(Eleocharis palustris), lady fern (Athyrium filix-femina)
and square-stalked St John's-wort Hypericum tetrapterum are
other indicators of the damp ground. Colourful summer wildflowers
include ragged-robin (Lychnis flos-cuculi), heath spotted orchid,
meadow vetchling (Lathyrus pratensis) and greater bird's-foot trefoil
Sub-site: Blackdown Summit
Acidic soils derived from the underlying Portishead Formation
(Old Red Sandstone) support one of the largest stands of dwarf
shrub heath on Mendip. Land higher than 300 metres is dominated
by mature ling, with less abundantly, other heathers (cross-leaved
heath Erica tetralix and bell heather E. cinerea),
bilberry (Vaccinium myrtillus) and typical heathland grasses.
Acid grassland forms a fringing mosaic in places, and is characterised
by common bent, western gorse, pill sedge (Carex pilulifera ),
green-ribbed sedge (C. binervis) and foxglove (Digitalis
purpurea) among other typical plants.
Paths through the heath support opportunistic and/or trample-resistant
plants, including the diminutive toad rush (Juncus bufonius),
heath rush (J. squarrosus), common yellow-sedge (Carex
viridula ssp. oedocarpa) and marsh cudweed (Gnaphalium
A few small mires are also present on Blackdown, providing suitably
wet and acidic conditions for Sphagnum mosses and a host
of other interesting wetland plants, including the creeping, pink-flowered
bog pimpernel (Anagallis tenella) and star sedge (Carex
echinata). The summit itself is quite wet, and purple moor-grass
can be found with bog asphodel (Narthecium ossifragum)
and other bog species.
Dense bracken has become established on the northern side of the
hill, a consequence partly of a history of occasional wildfires
and reduced grazing pressure on Blackdown, and of thicker soils.
Bracken produces thick litter and excludes most other species,
so is of low biodiversity interest.
Many ferns, mosses and liverworts flourish in the humid incision
of the East and West Twin Brooks, which rise on the northern side
of the hill. Here, lady fern, intermediate polypody (Polypodium
interjectum) and hard fern (Blechnum spicant) can
be found, alongside Dicranum majus and other bryophytes,
hairy wood-rush (Luzula pilosa) and bitter-vetch (Lathyrus
Blackdown supports many heathland insects and birds, many of which
are rare and/or declining. Sharp-eyed visitors may see emperor
moths (Saturnia pavonia) or their distinctive cocoons
in the heather, meadow pipits (Anthus pratensis), stonechats
(Saxicola torquata), skylarks (Alauda arvensis).
barn owls (Tyto alba) can also sometimes be glimpsed hunting
over the site.
SITE: BURRINGTON COMBE
Sub-site: Burrington Combe
The main ecological interest in the combe lies in the very species-rich
limestone grassland and scree that overlies the thin mineral soils.
Overall vegetation cover is very sparse, but supports many different
calcicolous plants that are typical of such habitats in the area.
Perennial herbs help to stabilise the loose stony soil, including
salad burnet, small scabious (Scabiosa columbaria), common
rock-rose and ploughman's-spikenard (Inula conyzae).
The warm, south-facing slopes of the combe are particularly important
for butterflies and other invertebrates.
In past years reduced grazing in the combe has allowed a rich
mixed native scrub cover to develop over grassland, scree and on
limestone crags and cliffs. Typical species include hawthorn, wild
privet (Ligustrum vulgare), yew, ash, wayfaring-tree (Viburnum
lantana) and, on more acidic and less steep slopes, rowan
(Sorbus aucuparia) gorse and elder (Sambucus nigra).
Whilst this heterogeneous habitats provides good cover for birds,
much of the scrub has recently been cut back, and grazing resumed
to prevent loss of valuable rich grassland.
Thin strips of limestone heath are present on leached soils close
to the top of the combe. Here, limestone grassland gives way to
vegetation with a heathy character, dominated by western gorse,
with bell heather and occasional ling. In turn, this grades into
coarse vegetation dominated by bramble (Rubus fruticosus),
bracken and hawthorn on Burrington Ham.
Caves within the combe support populations of hibernating bats,
including both species of horseshoe bat.
SITE: SOUTH FLANK
Sub-site: Crook Peak to Shute Shelve Hill
On a prominent south and west facing escarpment, this extensive
estate comprises a very large area of very rich Mendip downland
and includes a very wide range of different habitats, including
some that have a restricted distribution.
Immature calcareous soils are dominant on many of the steeper
slopes, and a rich limestone flora has developed. Its composition
varies, but includes many typical unimproved grassland indicator
species including wild thyme, dwarf thistle, dropwort (Filipendula
vulgaris), meadow oat-grass and yellow-wort (Blackstonia
perfoliata). On parts of Crook Peak and Shute Shelve Hill,
sparse, low-growing vegetation is exceptionally rich in places,
and supports a number of rarities including honewort (Trinia
glauca), somerset hair-grass (Koeleria vallesiana),
Cheddar pink and several rare lichens, which are a prominent feature
of this sward.
Low craggy limestone outcrops and small areas of limestone pavement
offer refuge to small crevice-dwelling ferns, including maidenhair
spleenwort, wall-rue and rustyback. More uncommon plants found
in this habitat include spring cinquefoil and basil thyme (Clinopodium
Upslope, for example near the summit of Crook Peak and on the
upper parts of Wavering Down, soils give way to acidic loessic
material, and limestone grassland is replaced by acid dwarf-shrub
heath and bracken. Western gorse is the most common shrub, accompanied
by both ling and bell heather. Locally, this is transitional to
acid grass-heath, an unusual type of community where dwarf shrubs
cover less than 70% of the ground. Here, heathers and gorses are
juxtaposed with sweet vernal-grass, heath-grass (Danthonia
decumbens), tormentil, sheep's-fescue and red fescue (Festuca
rubra). These slopes are unusual in the mosaic that is formed
between patches of calcicole and calcifuge vegetation. Locally,
a good mixture of scrub is present, with high levels of gorse,
hawthorn, blackthorn, roses (Rosa spp.) elder and hazel.
King's Wood is an ancient woodland with a documented history reaching
back as early as the 13th century. It is mostly semi-natural in
character, and supports a very rich flora and fauna. Ash standards
dominate, along with pedunculate oak, and small-leaved lime (Tilia
cordata), the latter being especially abundant as standards
and pollards near the old boundary banks. Field maple and wild
Cherry Prunus avium are less frequent. The understorey
is well-developed in King's Wood, with hazel, hawthorn and holly
being particularly characteristic. Pollarded trees within the wood
suggest that it has been managed as wood-pasture in the past few
centuries. A rich ground flora is present in the wood, with ancient
woodland indicator species typical of Mendip limestone woods. In
spring, bluebells, ramsons and dog's-mercury form dense carpets,
with less frequently, toothwort, sanicle, moschatel, wood anemone
and woodruff (Galium odoratum).
Limestone boulder scree is also frequent in the upper parts of
the wood, and this is covered by dense growth of mosses. King's
Wood also supports a number of notable epiphytic lichens.
Many species of invertebrate are found in King's Wood, including
ash-black slug (Limax cinereoniger), a characteristic
ancient woodland species. Woodland bird species include chiffchaff
(Phylloscopus collybita), blackcap, cuckoo (Cuculus
canorus), and dormice occur locally.
Sub-site: Axbridge Hill and Fry's Hill
Thin limestone loams overlying limestone and dolomitic conglomerate
support a very rich calcareous flora, which varies in composition,
but typically includes sheep's-fescue, crested hair-grass, common
rock-rose and wild thyme. In places the rare somerset hair-grass
can also be found.
Rock bluffs and limestone screes support a distinctive assemblage
of species, including slender bedstraw, sea stork's-bill (Erodium
maritimum) which is rare so far inland, dwarf mouse-ear and
rustyback, wall-rue and maidenhair spleenwort ferns. Saxicolous
(rock-dwelling) lichens and bryophytes are very diverse on the
bare rock and thin soils associated with rock outcrops.
Locally, leached soils upslope have developed a limestone heath
vegetation, characterised by an intimate juxtaposition of lime-loving
plants with more calcifugous species, including western gorse,
ling, bell heather and tormentil.
Scrub and broadleaved woodland are found on lower slopes, and
over scree, and provide a further dimension to the range of habitats.
The combination of rich vegetation and warm, south-facing aspect
is highly attractive to butterflies, and the area supports a very
rich lepidoptera fauna. Brown argus (Aricia agestis),
dark green fritillary (Argynnis aglaja), green hairstreak
(Callophrys rubi) and many other butterfly and moth species
have been recorded.
The nationally rare Greater and Lesser Horseshoe Bats roost within
SITE: PRIDDY AREA
Sub-site: Priddy Mineries
The biodiversity and habitats of Priddy Mineries reflects the
area's past history of lead mining. Valley mire, open water, wetland
habitats and lead-rich spoil heaps are all present, and the site
supports a very wide range of flora and fauna. It is especially
important for its rich wetland flora, supporting good populations
of all three British newts, as well as frogs and toads. Common
Lizard and Adder are commonly seen, particularly in areas of the
site where purple moor-grass forms large tussocks.
Open water (mining pools) support a very rich invertebrate fauna,
including many different species of dragonfly.
Bare mining spoil and dams are high in lead and other heavy metals,
and this generally deters vegetation growth. The rare alpine penny-cress
is one of the early pioneers of bare slag, occurring alongside
sea campion Silene uniflora, which is rare so far inland
in Somerset. Elsewhere the loose slag is stabilised by rafts of
mosses and lichens. Other spoil heaps in the valley bottom have
been colonised by a neutral grassland which is moderately diverse.
cowslip (Primula veris), yellow-rattle (Rhinanthus
minor) and lady's bedstraw can be all be found.
Valley mire is a very uncommon habitat in the Mendip Hills, and
it is well-developed at Priddy. Its tussocky appearance is due
to an abundance of purple moor-grass, but less frequent associates
include hare's-tail cottongrass (Eriophorum vaginatum)
which is rare on Mendip, bog asphodel and cross-leaved heath and
several species of Sphagnum moss. Nutrient-poor water
in the northern pool supports bottle sedge (Carex rostrata),
water horsetail (Equisetum fluviatile), and common spike-rush.
Submerged plants include broad-leaved pondweed (Potamogeton
natans) and the floating form of bulbous rush (Juncus
Elsewhere in the wet valley bottom, greater tussock-sedge (Carex
paniculata) forms large and distinctive tussocks a metre
or more high, alongside young willow carr and large shuttlecocks
of lady fern (Athyrium filix-femina). This species is
one of only a few that can tolerate metalliferous soils.
On drier valley slopes, an extensive mosaic of acid grassland
and dwarf shrub heath has developed. Bell heather and ling co-exist
with gorse and western gorse, whilst wavy hair-grass (Deschampsia
flexuosa) and tormentil can be found in the dry grassland.
Sub-site: Stockhill Plantation (Chewton mineries)
Mixed conifer plantation now overlies former lead workings, although
evidence of these can still be seen in the form of worked-out rakes
and gruffy ground.
In clearings and beside rides on Stockhill, the influence of the
underlying Devonian sandstone can be seen in the prominence of
heathland and acid grassland plants. Ling and western gorse are
frequent, along with purple moor-grass, and other typical calcifuges.
The site is notable for the presence of nightjar (Caprimulgus
europaeus) and long-eared owl (Asio otus), as well
as a wide range of other birds typical of lowland conifer/heath
In places, lead contamination in the soil is high, preventing
either tree growth or natural regeneration. These open areas are
home to a diminutive and very rare moss. Ditrichum plumbicola is
endemic to Europe where it is found only in Britain and Germany,
and is restricted to lead-mine spoil.
Sub-site: Draycott Sleights
On Mendip, 'sleight' means sheep-pasture, and this site has been
managed by traditional sheep-grazing for centuries. Now a nature
reserve, Draycott Sleights occupies a steep south-west-facing scarp
slope overlooking the Somerset Levels. Its principal habitats are
herb-rich limestone grassland with scattered scrub, rocky limestone
crags, small cliffs and rock exposures.
The limestone grassland supports a wide range of calcicolous herbs,
sedges and grasses. On the slopes the most abundant grasses and
sedges include upright brome, crested hair-grass (Koeleria
macrantha), sheep's-fescue, quaking-grass and glaucous sedge
(Carex flacca). The grassland is rich in herbs supporting
squinancywort (Asperula cynanchica), yellow-rattle, kidney
vetch (Anthyllis vulneraria) and many other typical species.
Orchids that might be seen in summer include pyramidal orchid (Anacamptis
pyramidalis) and greater butterfly orchid (Platanthera
Low limestone crags and bluffs provide shelter for small ferns
and crustose lichens in shades of yellow, white and grey, and in
spring, support the diminutive annual rue-leaved saxifrage (Saxifraga
tridactylites) in pockets of bare soil.
The northern part of Draycott Sleights overlies Burrington Oolite
and Black Rock Limestone, and supports a slightly different calcareous
grassland community, which is dominated by sheep's-fescue and meadow
oat-grass (Helictotrichon pratense). Many different, low-growing
herbs are also present, including the uncommon green-winged orchid
in spring. In summer, many different herbs attract butterflies
and other invertebrates. Blue butterflies are especially notable,
and include the local adonis blue (Lysandra bellargus)
and silver-studded blue (Plebejus argus).
Sub-site: Rodney Stoke (Stoke Woods)
Rodney Stoke National Nature Reserve encompasses broad-leaved
woodland, scrub and limestone grassland on two south-facing spurs
of the Mendip scarp.
Big Stoke and Little Stoke Woods are mostly ancient in origin,
and originally managed as coppice but were almost entirely clear-felled
in the 1914–18 war, followed by localised felling in 1939.
The canopy is now of two distinct age-classes, with an extensive
hazel understorey. The woodland is a good example of a typical
Mendip ash wood, and supports three different woodland communities.
Stools of coppiced small-leaved lime are frequent in the wood,
and pedunculate oak partially replaces ash as the main canopy tree
where soils are more neutral in character. Wild service-tree (Sorbus
torminalis) is locally distributed in the wood.
Whilst hazel dominates the understorey, a range of other limestone-loving
shrubs are also frequent, including buckthorn (Rhamnus cathartica)
and guelder rose (Viburnum opulus).
Many typical ancient woodland indicator species are found in the
ground flora. Dog's-mercury, bluebell and hart's-tongue (Phyllitis
scolopendrium) are abundant. Primroses (Primula vulgaris)
wood spurge (Euphorbia amygdaloides) and wood sedge (Carex
sylvatica) are frequent along the footpath through the wood.
More locally, there is spurge-laurel (Daphne laureola),
nettle-leaved bellflower (Campanula trachelium), early purple
orchid, herb Paris and toothwort. Purple gromwell (Lithospermum
purpureocaeruleum), a nationally rare herb, also occurs at
Rodney Stoke; it is not uncommon in old limestone woodlands in
the Cheddar area.
Many ferns, bryophytes and fungi flourish in the humid shelter
of the woodlands, and boulders and rock outcrops support thick
mats of mosses and liverworts. Common large mosses include Thamnobryum
alopecurum , and Atrichum undulatum , whilst the
leafy liverwort Porella platyphylla is abundant on old
Rich limestone grassland is present locally, and where soils are
more leached on higher ground, dwarf-shrub heath occurs locally,
with western gorse and ling.
Badgers are frequent in the woodland, and Big Stoke Wood supports
roosting populations of bat. Many birds also breed locally and
invertebrates are abundant. Purple hairstreak (Quercusia quercus)
can sometimes be seen in areas where oaks are present, and marbled
white (Melanargia galathea) is a frequent flyer.
SITE: WOOKEY AND WELLS
Sub-site: Ebbor Gorge
Ancient ash woodland dominates the steep rocky limestone slopes
of Ebbor Gorge, and is of a varied age structure. It is managed
as traditional rotational coppice-with-standards, and is mainly
dominated by ash and pedunculate oak. Associated trees include
hornbeam (Carpinus betulus), field maple and beech, whilst
the understorey is overwhelmingly dominated by coppiced hazel,
with lesser amounts of spindle (Euonymus europaeus), dogwood
(Cornus sanguinea) and other typical calcicolous shrubs.
The ground flora is very rich, with many ancient woodland species,
and includes yellow archangel (Lamiastrum galeobdolon),
dog's-mercury, wild anemone and bluebell. On wetter ground in the
bottom of the gorge, Opposite-leaved golden-saxifrage is abundant,
with enchanter's-nightshade (Circaea lutetiana), moschatel
(Adoxa moschatellina) and wood sedge.
Butterflies are abundant at Ebbor Gorge, and the site supports
some rare species that require a well-developed and complex woodland
structure. These include white-letter hairstreak (Strymonidia
w-album) and high brown fritillary (Argynnis edippe).
Many others are found on the rich limestone grassland.
Cliffs, scree and bluffs in the gorge itself are home to many
ferns, lower plants, lichens and fungi, which are favoured by the
sheltered, very humid microclimate. More than 150 lichen species
have been recorded, in rich communities on the limestone outcrops
and older trees, and the gorge also supports more than 100 species
of moss and liverwort, including several rarities.
Small caves in the gorge are valuable roosting sites for both
greater and lesser horseshoe bats.
Rich, unimproved limestone grassland occurs extensively at the
top of the gorge, and supports a range of typical calcicoles, for
example common rock-rose, salad burnet, wild thyme and large thyme
(Thymus pulegioides). Localised patches of leached soil
support limestone heath, with a limited range of calcifuge plants,
including bell heather and gorse.
Sub-site: Wookey Hole
Wookey Hole caves support an important roost of the nationally
rare greater gorseshoe bat.
North of the cave complex, two large field enclosures lie on steep,
south-west-facing slopes. These pastures have escaped agricultural
improvement, and support an extensive stand of short calcareous
grassland that has developed over Dolomitic Conglomerate. The rich,
tightly grazed turf is characterised by relatively low cover of
many species, with constant sheep's-fescue and meadow oat-grass.
Less frequent graminoids include common bent, heath-grass, spring
sedge (Carex caryophyllea) and quaking-grass. Herbs include
rough hawkbit (Leontodon hispidus), woolly thistle (Cirsium
eriophorum), musk thistle (Carduus nutans), and eyebright
SITE: HARPTREE AREA
Sub-site: Harptree Combe
Distinct habitats within Harptree Combe include old ash woodland,
rough grassland, marshy grassland alongside a small stream, and
limestone rock exposures. The ash woodland is very rich in woody
species, and interesting ground flora plants include dog's-mercury,
scaly male-fern (Dryopteris affinis), herb Paris, autumn
crocus and yellow archangel. In the upper reaches of the combe,
pedunculate oak replaces ash as the dominant canopy tree, with
old hazel coppice and drifts of bluebells. Limestone bluffs and
crags are frequent on the steep gorge slopes, and here hart's-tongue
and broad buckler-fern form large leafy shuttlecocks amongst a
lush carpet of bluebells and mosses. Fallen trees decomposing on
the valley floor provide a home for many different species of plant,
insect and fungus, including the brightly coloured scarlet cups
(Sarcoscypha coccinea) .
A fast-flowing small stream flows the length of the gorge, and
is fed by various small springs arising in the wood. Extensive
mats of opposite-leaved golden-saxifrage carpet the damper ground
on the valley floor, along with Ramsons.
The walls of the aqueduct and bare limestone rock faces are home
to many different mosses and fern. Species like brittle bladder-fern,
and the small mosses Didymodon ferrugineus and Didymodon
spadiceus are rare in southern England.