UPLAND CALCAREOUS GRASSLAND (UK BAP
PRIORITY HABITAT)
Summary
This priority habitat includes herb-rich upland grasslands and mountain avens Dryas
octopetala heaths. They share an array of base-tolerant plant species and are notable for a
large number of rare and scarce species
This habitat occurs in mosaics with other upland grasslands, more acid heaths, bogs and
montane communities, generally marking out areas of mineral soil where the underlying
rocks or irrigating water, or both, are moderately to strongly base-rich. The climate is the
typical upland combination of short, cool summers, long cold winters and plentiful wind, rain
and snow.
Herb-rich upland communities occur throughout the uplands of Scotland, but are most
extensive and best-developed in regions where much of the underlying rock is base-rich,
such as the Dalradian schists and limestones, the Durness limestone and basic exposures
of Moine schist and Lewisian gneiss. The Upland calcareous grassland priority habitat can
occur from a few metres above sea level to over 1000 m on the highest hills.
With the exception of the montane Dryas heath CG14, which occurs on inaccessible cliff
ledges for the most part, this habitat has developed from and needs to be maintained by
grazing. Some examples experience exceptionally heavy grazing so that the sward is less
than 5 cm tall and although this may prevent the plants flowering and setting seed it is likely
to maintain the high diversity of species. If there is no grazing or not enough, then species
diversity can be lost as the larger grasses and herbs increase at the expense of smaller or
less competitive herbs. Further, a layer of leaf litter and humus can accumulate, reducing
the influence of the base-rich soil so much that herb-rich swards can be transformed within a
few years into acid grassland or heath. Agricultural improvement and recreational
developments on the upland margins can also threaten vegetation of this type.
What is it?
Upland calcareous grassland is notable for the array of base-demanding herbs and shrubs
that grow among the grasses. Wild thyme Thymus polytrichus is the species that more than
any other separates the calcareous from the neutral and acid grasslands, and the sweet
scent of its crushed leaves and flowers is noticeable on still, warm days. The sward is made
up of species such as sheep’s fescue Festuca ovina, viviparous sheep's-fescue F. vivipara,
red fescue F. rubra, common bent Agrostis capillaris, velvet bent A. canina, sweet vernalgrass Anthoxanthum odoratum and, on damper soils, sedges such as carnation sedge
Carex panicea, flea sedge C. pulicaris, spring sedge C. caryophyllea and glaucous sedge C.
flacca. These give a distinct greyish look to the vegetation. Quaking grass Briza media and
meadow oat-grass Helictotrichon pratense also occur on the richer soils.
In U5c the dominant grass is mat grass Nardus stricta. The relative proportions of
graminoids and herbs varies between the communities: the Festuca-Agrostis-Thymus
grassland CG10 can be entirely dominated by grasses; the Festuca-Agrostis-Alchemilla
grassland CG11 has a more herb-rich sward in which the yellow flowers of alpine lady’s
mantle Alchemilla alpina are conspicuous in summer; the Festuca-Alchemilla-Silene
community CG12 is generally dominated by herbs and the patches are a much brighter
green than the more grassy swards.
Typical herbs found in all of these swards include meadow buttercup Ranunculus acris,
selfheal Prunella vulgaris, ribwort plantain Plantago lanceolata, yarrow Achillea millefolium,
alpine lady’s mantle Alchemilla alpina and A. glabra. On damp or flushed soils these are
joined by species such as water avens Geum rivale, lesser clubmoss Selaginella
selaginoides, meadowsweet Filipendula ulmaria, fairy flax Linum catharticum and
globeflower Trollius europaeus.
At higher altitudes and in the far north these grasslands are home to more montane
calcicoles such as alpine bistort Persicaria vivipara, hair sedge Carex capillaris, alpine
meadow-rue Thalictrum alpinum, moss campion Silene acaulis and cyphel Minuartia
sedoides. The mountain avens Dryas octopetala swards CG13 and CG14 share the species
of the other calcareous grasslands, growing through a creeping mat of D. octopetala with its
scalloped, glossy, dark green leaves and large cream flowers in, early summer.
The bryophyte element in all of these grasslands is similar, with species such as Hypnum
lacunosum, Tortella tortuosa, Hylocomium splendens, Ctenidium molluscum and, at higher
altitudes, Ditrichum flexicaule s.l., Orthothecium rufescens and the liverwort Herbertus
stramineus.
This habitat is notable for a large number of rare and scarce species including false sedge
Kobresia simpliciuscula, purple oxytropis Oxytropis halleri, alpine forget-me-not Myosotis
alpestris, alpine milk-vetch Astragalus alpinus, alpine bartsia Bartsia alpina, alpine pearlwort
Sagina saginoides, alpine gentian Gentiana nivalis, Scottish primrose Primula scotica, and
bryophytes Timmia norvegica, T. austriaca, Ptychodium plicatum, Pseudoleskeela incurvata,
Saelania glaucescens, Seligeria trifaria, Syntrichia princeps, S. norvegicum and
Campylophyllum halleri.
How do I recognise it?
These are grasslands on base-rich soils in the uplands. They consist of mixtures of grasses
such as Festuca ovina, Agrostis capillaris and Anthoxanthum growing with Thymus
polytrichus and a rich array of small base-tolerant herbs. Dryas octopetala is the dominant
species in some examples and these are really more calcareous heaths than calcareous
grasslands. Examples below the tree-line are produced and maintained by grazing; those in
the montane zone are possibly near-natural climax communities but probably still need at
least low levels of grazing to keep the larger, more vigorous plants in check. These
grasslands are home to many of our most rare and threatened plant species. They are an
important food source for grazing mammals, invertebrates and upland birds.
Differentiation from other Priority Habitats
In most cases the NVC community separates Upland calcareous grassland and Lowland
calcareous grassland priority habitats: CG1-CG8 are lowland communities and CG11-CG14
and U5c are upland ones. CG10 (and in England CG9) can occur in both lowland and
upland priority habitats and should be divided according to whether it occurs above the
upper limits of agricultural land (upland) or within enclosed fields (lowland). Examples on
coastal cliffs are classed as lowland. Examples of CG10 and CG13 on limestone pavements
belong to the Limestone pavements priority habitat.
Definition in relation to other habitat classifications
Classification
NVC
Habitat types belonging to this UK BAP priority habitat
CG10 (all upland examples except those on coastal cliffs or
limestone pavements), CG11-12 (all examples), CG13-14 (where
not on limestone pavement), U4c and other flushed, herb-rich
examples and U5c (all examples). In N. England this priority
habitat also includes upland examples of CG9 (this NVC
community is not recorded in Scotland).
(CG10-14 are all included in the Scottish Biodiversity List.)
Phase 1
UK BAP broad
habitat
B3 (all upland examples).
Examples of this priority habitat conforming to NVC CG10-14,
U4c and related forms, and U5c, as described, belong to the
broad habitat – Calcareous grassland.
CG10 is the most widespread of the NVC grassland communities in this priority habitat, and
it occurs over the greatest altitudinal range. It is also well represented in the uplands of
England and Wales. CG11 is common at higher altitudes. It occurs in northern England but
not Wales. CG12 and CG14 are confined to basic soils at high altitudes and are uncommon
in Scotland and rare in Wales; CG13 is confined to limestone soils at low altitudes in the far
north and west Highlands. U5c has been recorded in small stands throughout the British
uplands. CG9 in upland habitats also belongs to this priority type, but does not occur in
Scotland.
Definition in relation to legislative classifications
Classification
Habitats
Directive Annex I
SNH SSSI
habitat features
Habitat types belonging to this UK BAP priority habitat
H6170 (all occurrences - this Annex I type includes all of the
Upland calcareous grassland priority habitat in Scotland).
Subalpine calcareous grassland and Alpine calcareous grassland
SSSI feature types (CG10-11 and CG12-14 respectively). This
priority habitat can also be part of a mosaic of two or more SSSI
habitat features classed together as the Upland assemblage
SSSI habitat feature.
Where is it?
Upland calcareous grassland comprises communities of base-rich mineral soils derived from
rocks such as limestone, basalt and calcareous schists. The base status of the soil tends to
be between 5.3 and 7.5 (McVean and Ratcliffe 1962) and is maintained by physical and
chemical weathering or by flushing with base-rich water. The grasslands occur on hillsides,
on consolidated scree, along streamsides and in glens. They are common along cliff-bases,
where they may have many species in common with the vegetation of the ungrazed ledges.
The altitudinal range is from near sea-level to over 1000 m. The higher examples may be
covered by snow for much of the winter. Stands vary in size from a few square metres to
several hectares and occur in mosaics with a range of heaths and other grasslands. The
Dryas-Silene community CG14 is confined to ungrazed ledges or otherwise inaccessible
sites away from grazing animals.
These grasslands generally form mosaics with upland acid grasslands or heaths or, at
higher altitudes, with montane habitats. They can be dissected with base-rich springs and
flushes where water reaches the surface of the ground. They can occur on river banks and
vegetated river shingle adjacent to stands of blanket bog. They are common too around
exposures of limestone pavement. Bands of calcicolous grassland along cliff bases may
have many species in common with the vegetation of the ungrazed ledges above. They may
also occur on the margins of grazed woodland.
Upland calcareous grassland is most common and widespread in the Scottish highlands,
where all the communities occur. CG10 is the least exacting and occurs throughout the
southern uplands and on smaller areas of hill ground within the more lowland areas of Fife
and the Central Belt. CG13 is confined to the limestone areas in the far north and west of
Scotland from Lismore in the south-west to Durness and along the north coast to Invernaver.
CG10 is common throughout the British uplands. CG11 occurs in the Scottish highlands and
in northern England; CG12 and CG14 occur in the Scottish highlands and North Wales but
all three are far more common in Scotland than they are further south, and CG13 is confined
to Scotland. The total extent of this type of vegetation in Scotland is estimated to be around
7000 ha (SNH BAP Review), but may be as much as 10,000 – 13,000 ha (UK BAP Priority
Habitat Descriptions).
Upland examples of the Sesleria-Galium grassland CG9 belong to this priority habitat.
Though extensive on Carboniferous limestone soils in northern England, CG9 does not
occur in Scotland.
There are similar upland calcareous grassland communities in mainland Europe and in the
Faroe Islands.
What is special about it?
Some species of special conservation status recorded in this Priority Habitat are listed
below.
Group
bees,
w asps and
ants
bees,
w asps and
ants
bees,
Com mon
nam e
ruby-tailed
w asp
Latin nam e
Chrysura hirsuta
UK BAP
priority
list
y
EC
Habitats
Directive
Annex II
Scottish
Biodiversity
List
y
northern
osmia
Osmia inermis
y
y
w all mason
Osmia parietina
y
y
Red
Data
List
Wildlife
and
Countryside Act
(1981)
Group
w asps and
ants
beetles
bird
bird
bird
birds
butterflies
butterflies
butterflies
flow ering
plant
flow ering
plant
flow ering
plant
flow ering
plant
flow ering
plant
flow ering
plant
flow ering
plant
flow ering
plant
flow ering
plants
flow ering
plants
flow ering
plants
flow ering
plants
flow ering
plants
flow ering
plants
flow ering
plants
flow ering
plants
fungi
fungi
fungi
fungi
fungi
fungi
mammals
moss
moss
moss
moss
moss
Com mon
nam e
bee
violet oilbeetle
lapw ing
golden plover
ring ouzel
skylark
small blue
northern
brow n argus
small heath
close-headed
alpine-sedge
simple bog
sedge
purple
oxytropis
alpine forgetme-not
alpine
pearlw ort
alpine bartsia
Latin nam e
UK BAP
priority
list
EC
Habitats
Directive
Annex II
Scottish
Biodiversity
List
Meloe violaceus
y
y
Vanellus vanellus
Pluvialis apricaria
Turdus torquatus
Alauda arvensis
subsp.
arvensis/scotica
Cupido minimus
Aricia artaxerxes
y
y
y
y
y
y
y
y
y
y
y
Coenonympha
pamphilus
Carex norvegica
y
y
Red
Data
List
y
y
y
y
y
y
y
Kobresia
simpliciuscula
Oxytropis halleri
y
y
y
y
Myosotis alpestris
y
y
Sagina saginoides
y
y
Bartsia alpina
y
y
alpine gentian
Gentiana nivalis
y
y
Scottish
primrose
field gentian
Primula scotica
y
Gentianella
campestris
Pseudorchis albida
y
y
y
y
y
y
Hieracium sect.
Alpestria
Arenaria norvegica
subsp. norvegica
Astragalus alpinus
y
y
y
y
y
y
y
y
Astragalus danicus
y
y
y
Coeloglossum viride
y
y
y
cyphel
Minuartia sedoides
y
y
y
stalked
puffball
date coloured
w axcap
big blue
pinkgill
dark-purple
earthtongue
spignel rust
alpine rust
Tulostoma niveum
y
y
Hygrocybe spadicea
y
y
Entoloma bloxamii
y
y
Geoglossum
atropurpureum
Nyssopsora echinata
Puccinia
septentrionalis
Cervus elaphus
Hypnum revolutum
y
y
y
y
y
y
small-w hite
orchid
a haw kweed
arctic
sandw ort
alpine milkvetch
purple milkvetch
frog orchid
red deer
revolute plaitmoss
Norw ay
timmia
brow n
mountain
leskea
plaited leskea
blue dew -
Timmia norvegica
Pseudoleskea
incurvata
Ptychodium plicatum
Saelania glaucescens
y
Wildlife
and
Countryside Act
(1981)
y
y
y
y
y
y
y
y
y
y
y
y
y
y
Group
moss
moss
moss
moss
mosses
reptiles
Com mon
nam e
moss
trifid rockbristle
brow n screw moss
Norw ay
screw -moss
haller’s
feather-moss
sheathed
timmia
common lizard
Latin nam e
UK BAP
priority
list
EC
Habitats
Directive
Annex II
Scottish
Biodiversity
List
Red
Data
List
Seligeria trifaria
y
Syntrichia princeps
y
Syntrichia norvegica
y
y
Campylophyllum
halleri
Timmia austriaca
y
y
y
y
y
Zootoca vivipara
y
y
Wildlife
and
Countryside Act
(1981)
y
Upland calcareous grassland forms patches of very high diversity within larger areas of less
species-rich heath and acid grassland, so much of the nature conservation interest in any
particular area can be concentrated into these (along with some of the mires q. v.). Some
examples are extremely species-rich with over 60 species in a 2m x 2m plot. These
grasslands are among the main habitats in Scotland for the uncommon upland plants
Alchemilla wichurae, rock sedge Carex rupestris, black alpine-sedge C. atrata, sheathed
sedge C. vaginata, bearded couch Elymus caninus var. donianus, dark-red helleborine
Epipactis atrorubens, rock whitlowgrass Draba norvegica, spring sandwort Minuartia verna,
alpine cinquefoil Potentilla crantzii, alpine mouse-ear Cerastium alpinum, alpine speedwell
Veronica alpina, rock speedwell V. fruticans, alpine saxifrage Saxifraga nivalis and the
bryophytes Aulacomnium turgidum, Hypnum hamulosum, Conardia compacta, Rhytidium
rugosum, Schistidium robustum, S. trichodon, Hylocomium pyrenaicum and Herbertus
stramineus as well those listed in the table above.
Spring gentian Gentiana verna, Teesdale violet Viola rupestris and bird’s foot-sedge Carex
ornithopoda are notable rarities in the northern English examples of this priority type.
The Dryas heaths CG13 and CG14 are surviving remnants of the sort of shrubby, flowery
vegetation that is thought to have been widespread throughout Britain during the last glacial
period and the immediate post-glacial times.
The flowering shrubs and herbs are a valuable nectar source for upland insects such as
bumblebees.
CG11 and U5c are important habitats for the scarce Mountain Ringlet butterfly Erebia
epiphron. The insects drawn to the flowering herbs and shrubs are fed upon by upland birds
such as lapwing Vanellus vanellus, golden plover Pluvialis apricaria, ring ousel Turdus
torquata, meadow pipit Anthus pratensis, skylark Alauda arvensis and wheatear Oenanthe
oenanthe.
The grasslands are grazed by sheep, red deer, roe deer and sika deer, rabbits, mountain
hares and field voles.
How do we manage it?
Almost all examples of Upland calcareous grasslandis produced and maintained by grazing,
the exception being the Dryas-Silene community CG14 which is confined to inaccessible
sites. Some examples are grazed to within 2 cm of the ground without losing their diversity,
but too little grazing can be damaging as the larger plants and more robust grasses increase
at the expense of the smaller and less-competitive species. Grazing herbivores naturally
seek out and preferentially graze these patches of grassland, so it is common to find very
short swards of Upland calcareous grassland set in a matrix of tall Calluna heath, for
example. However, very heavy grazing tends to extend the areas of grassland by
eliminating the dwarf shrubs in heaths. In some protected areas, it can be a challenge to
find a level of grazing that will maintain the rich open swards of these grasslands without
damaging the surrounding bogs and heaths where these are also of interest. Dryas
octopetala cannot tolerate excessively heavy grazing. The Dryas-Carex community CG13
can be converted to CG10 grassland by excessive grazing, and it seems poss ible that CG14
was once more widespread in the Scottish hills.
CG10 swards at low altitudes may be converted to improved agricultural grassland by
reseeding and fertilisation. Some examples of CG10 might revert to scrub and eventually to
upland woodland in the absence of grazing, though the more montane CG11, CG12 and
CG14 are likely to be near-natural climax communities. Even these may depend on light to
moderate grazing to keep the more vigorous species in check.
Moderate grazing by a diversity of wild and domestic animals is probably the best way to
maintain this habitat.
References, links and further reading
Averis, A., Averis, B., Birks, J., Horsfield, D., Thompson, D., & Yeo, M. 2004. An Illustrated
Guide to British Upland Vegetation. Peterborough, JNCC http://jncc.defra.gov.uk/page-2463
Ellis, N.E. and Munro, K. 2004. A preliminary review of the distribution and extent of
BAP priority habitats across Scotland. Scottish Natural Heritage Commissioned Report
No.044 (ROAME No. F00NA02).
http://www.snh.org.uk/pdfs/publications/commissioned_reports/F00NA02.pdf
Rodwell, J.S., ed. 1991a British plant communities Volume 3: Grasslands and montane
communities. Cambridge, Cambridge University Press.
Rodwell, J.S., Dring, J.C., Averis, A.B.G., Proctor, M.C.F., Malloch, A.J.C., Schaminee,
J.H.J. & Dargie, T.C.D. 1998. Review of coverage of the National Vegetation Classification.
Joint Nature Conservation Committee contract report F76-01-170. Coordinated by the Unit of
Vegetation Science, Lancaster University.
UK BAP 2008. http://jncc.defra.gov.uk/pdf/UKBAP_BAPHabitats-58-UplandCalcGrass.pdf
Usher, M.B., Bain, C. and Kerr, A. eds. 2000. Action for Scotland's Biodiversity. Scottish
Biodiversity Group. Edinburgh, The Scottish Executive and The Stationery Office.
Common Standards Monitoring guidance http://www.jncc.gov.uk/page-2199
Countryside Survey http://www.countrysidesurvey.org.uk
National Biodiversity Network (NBN) Gateway https://data.nbn.org.uk/
Scottish Natural Heritage website: http://www.snh.gov.uk/
UK BAP information on JNCC website: http://jncc.defra.gov.uk/default.aspx?page=5155