Upland Calcareous Grassland

Upland calcareous grasslands occur on shallow, lime-rich soils.  Most examples are found above the upper limit of agricultural enclosure, in both the sub-montane and montane zones.  They also occur within unenclosed moorland at lower elevations, and, in north-west Scotland, descend to sea level.

These grasslands typically occur as a mosaic with other habitat types.  They are generally managed as rough grazing for domestic livestock.  The sward is generally short, species-rich, and formed from grasses, mosses, sedges, and a high proportion and variety of herbs - as indicated in the box below.  Some sites, however, occur over more broken, rocky ground, which is less heavily grazed and has a taller, tussocky, and sometimes more open sward.  This is a relatively rare habitat that supports a wide range of uncommon species.

 

Characteristic plants

  • Grasses.    Blue moor-grass Sesleria caerulea [Sesleria albicans]; brown bent Agrostis vinealis; common bent Agrostis capillaris; crested hair-grass Koeleria macrantha; heath-grass Danthonia decumbens; mat-grass Nardus stricta; meadow oat-grass Helictotrichon pratense; quaking-grass Briza media; red and sheep's fescue Festuca rubra/ovina; sweet vernal grass Anthoxanthum odoratum
  • Sedges and sedge-like plants.    Carnation sedge Carex panicea; false sedge Kobresia simpliciuscula; flea sedge Carex pulicaris; glaucous sedge Carex flacca; hair sedge Carex capillaris; spring sedge Carex caryophyllea
  • Herbs.   Alpine lady's mantle Alchemilla alpina; common bird’s-foot-trefoil Lotus corniculatus; common dog-violet Viola riviniana; common rock-rose Helianthemum nummularium; cyphel Minuartia sedoides; fairy flax Linum catharticum; harebell Campanula rotundifolia; heath bedstraw Galium saxatile; limestone bedstraw Galium sterneri; moss campion Silene acaulis; mossy saxifrage Saxifraga hypnoides; mountain avens Dryas octopetala; ribwort plantain Plantago lanceolata; selfheal Prunella vulgaris; tormentil Potentilla erecta; wild thyme Thymus praecox
  • Mosses.   Chalk comb-moss Ctenidium molluscum; glittering wood-moss Hylocomium splendens; woolly fringe-moss Racomitrium lanuginosum

 

Types of upland calcareous grasslands

  • Alpine and subalpine calcareous grasslands.   These occur on lime-rich soils and consist of short, often grazed, species-rich mixtures. Within the UK, this habitat occurs close to sea level, as well as at high altitudes. It is one of the most important upland habitats for rare arctic-alpine plants, and other rare montane or northern plants and animals, including the endemic Scottish primrose Primula scotica. Three recognised vegetation communities fall within this grassland group: Festuca ovina-Alchemilla alpina-Silene acaulis dwarf herb community; Dryas octopetala-Carex flacca heath; and Dryas octopetala-Silene acaulis ledge community. In general, such grassland contains a high proportion of arctic-alpine cushion herbs.
  • Upland calcareous dry grasslands and scrublands.   This is a widespread, but localised habitat type on well-drained calcareous soils in England. It also occurs more rarely in Wales, Northern Ireland and Scotland. Swards are generally maintained by grazing, and conspicuous suits of calcicole (calcium-loving) plants are a characteristic feature. Two recognised grassland communities occur within this group: Sesleria albicans-Galium sterneri and Festuca ovina-Agrostis capillaris-Thymus praecox grasslands. Variation within is mainly dependent on regional climatic conditions, local topography, soil depth and fertility, and grazing
  • Montane species-rich Nardus grasslands.   These tend to develop where localised base-rich flushes occur on siliceous bedrock. The soils have an acidic pH (mainly <6) and are derived from bedrocks with at least some silica. The altitudinal range varies from near sea level to 800900m up. This is an important habitat that supports a wide range of species, including Atlantic, Sub-Atlantic and Arctic-Alpine plants and invertebrates. Species present in the grassland tend to be those that avoid extreme conditions. Swards are closely grazed and consist of a complex mosaic of grasses, small herbs and bryophytes. Most of this habitat falls within calcareous grassland communities characterised by Festuca ovina-Agrostis capillaris-Alchemilla alpina or Festuca ovina-Agrostis capillaris-Thymus praecox; the remainder is classed as acidic grassland characterised by Festuca ovina-Agrostis capillaris-Galium saxatile or Nardus stricta-Galium saxatile.

 

Examples of important species found on upland calcareous grasslands

Bees  

  • Northern osmia Osmia inermis
  • Ruby-tailed wasp Chrysura hirsuta
  • Tormentil mining bee Andrena tarsata
  • Wall mason bee Osmia parietina

Birds

  • Lapwing Vanellus vanellus
  • Ring ouzel Turdus torquatus
  • Skylark Alauda arvensis arvensis
  • Yellow wagtail Motacilla flava flavissima

Butterflies

  • Mountain Ringlet Erebia epiphron
  • Northern Brown Argus Aricia artaxerxes
  • Pearl-bordered Fritillary Boloria euphrosyne
  • Small Blue Cupido minimus
  • Small Heath Coenonympha pamphilus

Flowering plants

  • Arctic sandwort Arenaria norvegica subsp. norvegica
  • Alpine milk-vetch Astragalus alpinus
  • Cyphel Minuartia sedoides
  • Field gentian Gentianella campestris
  • Frog orchid Coeloglossum viride
  • Purple milk-vetch Astragalus danicus
  • Small-white orchid Pseudorchis albida

 Fungi

  • Alpine rust Puccinia septentrionalis
  • Big blue pinkgill Entoloma bloxamii
  • Dark-purple earthtongue Geoglossum atropurpureum
  • Date-coloured waxcap Hygrocybe spadicea
  • Spignel rust Nyssopsora echinata
  • Stalked puffball Tulostoma niveum