Habitat Action Plan

Lowland calcareous grasslands are developed on shallow lime-rich soils generally overlying limestone rocks, including chalk. These grasslands are now largely found on distinct topographic features such as escarpments or dry valley slopes and sometimes on ancient earthworks in landscapes strongly influenced by the underlying limestone geology. More rarely, remnant examples occur on flatter topography such as in Breckland and on Salisbury Plain. They are typically managed as components of pastoral or mixed farming systems, supporting sheep, cattle or sometimes horses; a few examples are cut for hay.

The definition of calcareous grasslands covers a range of plant communities in which lime-loving plants are characteristic. In the context of this Action Plan, lowland types are defined as the first nine calcareous grassland National Vegetation Classification communities, CG1 to CG9. With the exception of CG9, Sesleria albicans - Galium sterneri grassland, which straddles both lowlands and uplands, these communities are largely restricted to the warmer and drier climates of the southern and eastern areas of the United Kingdom. Lowland sub-communities of CG9 occur in the more clement conditions around Morecambe Bay in Cumbria, while upland sub-communities occupy colder and wetter localities in the Pennines. Lowland calcareous grassland sites occur in both enclosed and unenclosed situations but typically below the upper level of agricultural enclosure in any particular district; calcareous grasslands situated in the unenclosed uplands are covered by a separate Action Plan. As defined here, lowland calcareous grassland only occurs in England and Wales. None of the communities CG1 to 9 has been recorded from Scotland. While limestone grassland in Northern Ireland has affinities to CG9, it is largely confined to open upland localities and around their margins; some CG6 has also been recorded, but only in very small and scattered stands around the coast.

The cover of lowland calcareous grassland has suffered a sharp decline in extent over the last 50 years. There are no comprehensive figures, but a sample of chalk sites in England surveyed in 1966 and 1980 showed a 20% loss in that period and an assessment of chalk grassland in Dorset found that over 50% had been lost between the mid-1950s and the early 1990s.

Current estimates put the amount of lowland calcareous grassland remaining in the United Kingdom around 33,000 to 41,000 ha with less than 1,000 ha of this in Wales. The bulk of the resource is found on chalk (25,000 to 32,000 ha), with major concentrations in Wiltshire, Dorset and the South Downs.

Lowland calcareous grasslands support a very rich flora including many nationally rare and scarce species such as monkey orchid Orchis simia, hoary rockrose Helianthemum canum and pasque flower Pulsatilla vulgaris. The invertebrate fauna is also diverse and includes scarce species like the adonis blue Lysandra bellargus, the silver-spotted skipper Hesperia comma, the Duke of Burgundy fritillary Hamaeris lucina and the wart-biter cricket Decticus verrucivorus. These grasslands also provide feeding or breeding habitat for a number of scarce or declining birds including stone curlew Burhinus oedicnemus and skylark Alauda arvensis.

Scrub is frequently associated with calcareous grassland and can contribute to local biodiversity by providing shelter for invertebrates and scrub edge conditions suitable for species such as bloody cranesbill Geranium sanguineum. Dwarf shrubs and herbs characteristic of acid soils are also sometimes associated with calcareous grassland, forming chalk or limestone heath. Limestone pavement is covered in a separate action plan.

Lowland calcareous grassland is an important habitat for a number of priority invertebrate, plant and birds. During plan implementation their requirements should be taken into account. The priority species include: leaf beetles Cryptocephalus sp.; (Cryptocephalus coryli, Cryptocephalus decemmaculatus, Cryptocephalus exiguus, Cryptocephalus nitidulus, Cryptocephalus primarius, Cryptocephalus sexpunctatus ) Northern brown argus Aricia artaxerxes, silver spotted skipper Hesperia comma, Adonis blue Lysandra bellargus, wart-biter grasshopper Decticus verrucivorous, a hover fly Doros profuges, several moths including the bordered gothic Heliophobus reticulata, pale shining brown Polia bombycina and the four spotted Tyta luctuosa and the prickly sedge Carex muricata ssp. muricata and the early gentian Gentianella anglica ssp. anglica.

The factors currently affecting calcareous grassland reduce the quality and quantity of the habitat, and its fragmentation brings increased risk of species extinctions in the small remnant areas. For example a survey of the Lincolnshire Wolds found that 66% of sites were less than 1 ha in size and none was more than 10 ha in size. The factors include:

Agricultural intensification by use of fertilisers, herbicides and other pesticides, re-seeding or ploughing for arable crops.

Farm specialisation towards arable cropping has reduced the availability of livestock in many lowland areas. The result is the increasing dominance of coarse grasses such as tor grass Brachypodium pinnatum and false oat grass Arrhenatherum elatius and invasion by scrub and woodland, leading to losses of calcareous grassland flora and fauna.

Over-grazing is a less widespread problem, and is sometimes associated with supplementary feeding, which can also can cause localised sward damage, due to trampling and long-term nutrient enrichment.

Development activities such as mineral and rock extraction, road building, housing and landfill.

Localised afforestation with hardwoods and softwoods.

Recreational pressure bringing about floristic changes associated with soil compaction at some key sites.

Invasion by non-native plants, including bird-sown Cotoneaster species, causes problems by smothering calcareous grassland communities at some sites.

Atmospheric pollution and climate change, the influence of which is not fully assessed.

Lowland calcareous grassland features prominently in the SSSI series in England and Wales. There are 616 SSSIs in England which have the habitat as a principal reason for notification and 22 in Wales with a further 16 here including the habitat among several of interest. Comprehensive information on the amount of the resource included within SSSIs is not available but is estimated to be between 60% to 70% in both England and Wales.

The value of the habitat has long been recognised in the NNR series, with 28 containing calcareous grassland in England and two in Wales, including Parsonage Down (Wiltshire), the Derbyshire Dales, Barnack Hills and Holes (Cambridgeshire), and the Gower Coast. Several sites are Local Nature Reserves including Great Orme`s Head (Conwy), Hackhurst Downs (Surrey) and Galley and Warden Hills (Bedfordshire). Several key sites are designated as common land, e.g. Rodborough Common (Gloucestershire).

Lowland calcareous grassland is included within the Festuco-Brometalia grassland identified in Annex 1 of the EC Habitats Directive as of Community interest. The habitat is a priority type if important orchid populations are present. Lowland calcareous grassland sites will form part of the Natura 2000 network. Species listed on Annex II of the Directive which occur in the habitat are early gentian Gentianella anglica, marsh fritillary Eurodryas aurinia, and large blue Maculinea arion. European Special Protection Areas for Birds include two important calcareous grasslands, Porton Down and Salisbury Plain.

Several plant, invertebrate and bird species of calcareous grassland are protected under the Schedules of the Wildlife and Countryside Act 1981.

Management agreements to conserve calcareous grassland on SSSIs have been made between owners and occupiers and NE or CCW. Agri-environment schemes play a major role in providing incentives to encourage the appropriate management of sites, including SSSIs (where a management agreement is not already in place). ESAs with a significant component of lowland calcareous grassland include Breckland, the South Downs, the South Wessex Downs and the Cotswold Hills. The Countryside Stewardship Scheme in England and Tir Cymen and the Habitat Scheme in Wales (which will be replaced in 1999 by the new all Wales agri-environment scheme Tir Gofal) also include calcareous grassland as an eligible habitat.

The Ministry of Defence is by far the largest landowner (by area) of calcareous grassland with several sites including very large areas on Salisbury Plain, the Stanford Training Area and Porton Down. The MoD is developing integrated management plans for their properties to take account of nature conservation.

A major contribution has been made by various non-governmental organisations to the conservation of species-rich calcareous grasslands in parts of the UK through the establishment of nature reserves.

Techniques for calcareous grassland creation are currently being researched and the impact of climate change monitored on calcareous grassland through a DETR project. MAFF is sponsoring research on reversion of arable to calcareous grassland in relation to ESA prescriptions. Long term monitoring of change at Porton Down and Wytham Woods as part of the Environmental Change Network is also relevant.

There is a need to assess the impact of atmospheric nutrient deposition and climate change in this and other types of lowland grassland.

The successful implementation of the habitat action plans will have resource implications for both the private and public sectors. The data in the table below provides an estimate of the current expenditure on the habitat, primarily through agri-environment schemes and grant schemes, and the likely additional resource costs to the public and private sectors. These additional resource costs are based on the annual average over 5 and 10 years. The total expenditure for these periods of time is also given. Three-quarters of the additional resources are likely to fall to the public sector.

Since Countryside Stewardship does not differentiate between upland and lowland calcareous grassland the figure presented for current expenditure is a proportion of the total expenditure equivalent to the area of lowland as compared to upland calcareous grassland.

Crofts, A. & Jefferson, R.G. (Eds.) (1994). The Lowland Grassland Management Handbook. NE/The Wildlife Trusts Peterborough.

Fuller, R.M. (1987). The changing extent and conservation interest of lowland grasslands in England and Wales: a review of grassland surveys 1930-84. Biological Conservation, 40, 281-300.

Gibson, C.W.D. (1995). Chalk grasslands on former arable land: a review. Bioscan (UK) Ltd, Oxford.

Gibson, C.W.D. & Brown, V.K. (1991). The nature and rate of development of calcareous grassland in southern Britain. Biological Conservation, 58, 297-316.

Hillier, S.H., Walton, D.W.H. & Wells, D.A. (Eds.) (1990). Calcareous grasslands - ecology and management. Bluntisham, Huntingdon.

Jefferson, R.G. & Robertson, H.J. (1996). Lowland grassland - a strategic review and action plan. English Nature Research Report No.163, Peterborough.

Jefferson, R.G. & Robertson, H.J. (1996). Lowland grassland - wildlife value and conservation status. English Nature Research Report No.169, Peterborough.

Rodwell, J.S. (Ed.) (1992). British Plant Communities Volume 3, Grasslands and Montane Communities. University Press, Cambridge.

Smith, C.J. (1980). The Ecology of the English Chalk. Academic Press, London.

The following LBAPs are working on Lowland calcareous grassland:

Originally published in: UK Biodiversity Group Tranche 2 Action Plans - Volume II: Terrestrial and freshwater habitats (December 1998, Tranche 2, Vol II, p57)