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.
Links with other action plans
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.
Current factors affecting the habitat
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, research and guidance
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.
Action plan objectives and targets
Arrest the depletion of lowland calcareous grassland throughout the UK.
Within SSSIs, initiate rehabilitation management for all significant stands of lowland calcareous grassland in unfavourable condition by 2005.
Achieve favourable status for all significant stands of lowland calcareous grassland within SSSIs by 2010.
For stands outside SSSIs, secure favourable condition over 30% of the resource by 2005.
For stands outside SSSIs, secure favourable condition over as near to 100% as is practicable by 2015.
Attempt to re-establish 1000 ha of lowland calcareous grassland of wildlife value at carefully targeted sites by 2010.
Proposed actions with lead agencies
Policy and legislation
Take account of the conservation requirements of calcareous grassland when developing and adjusting agri-environment schemes. Design measures to suit local needs and in particular target local concentrations of semi-natural calcareous grassland. (Action: CCW, NE, MAFF, WOAD)
Develop and implement strategies to restore and expand the cover of unimproved calcareous grassland, taking into account the need to ameliorate the negative effects of isolation, fragmentation, small patch size and scrub encroachment. (Action: CCW, NE, MAFF, WOAD)
Support initiatives to conserve unimproved calcareous grassland within local government development plans and related policy, in forest management and planting schemes and by special projects. (Action: EA, DETR, FC, LAs, WO)
Consider mechanisms by which lowland calcareous grassland within areas designated as common land can be brought under sympathetic management. (Action: DETR, MAFF, WOAD)
Site safeguard and management
Keep the extent of SSSI coverage under review and notify further sites as necessary to fill significant gaps in coverage. (Action: CCW, NE)
Complete the designation of lowland calcareous grassland SPAs and SACs and prepare and implement management plans by 2004. (Action: CCW, DETR, NE, JNCC)
Secure the uptake of positive management with owners and occupiers of SSSIs where necessary to achieve favourable conservation conditions, and promote the uptake of such agreements on other wildlife sites. (Action: CCW, NE)
Secure the positive management of lowland calcareous grassland sites within the ownership or management of the Ministry of Defence and voluntary conservation bodies, and draw up site management plans with clear targets for this habitat and associated priority species for these sites by 2004. (Action: NE, MoD)
Consider the need to manage further key sites as National Nature Reserves and, where appropriate, support acquisition and management by conservation organisations. (Action: CCW, NE)
Encourage the development of new management techniques where required, e.g. for weed control, and the setting up of local farm networks, e.g. for livestock provision, that will ensure sympathetic management is possible. (Action: CCW, NE, JNCC, MAFF, WOAD)
Contribute to the implementation of relevant species action plans for rare and declining species associated with lowland calcareous grasslands in conjunction with the relevant species steering group. (Action: CCW, NE, MAFF, WOAD)
Encourage, develop and disseminate best practice for unimproved calcareous grassland management, in particular the integration of conservation management into agricultural practice. (Action: CCW, NE, LAs, MAFF, WOAD)
Produce and disseminate guidelines for appropriate methods and approaches to establish new stands of lowland calcareous grassland of wildlife value. (Action: CCW, NE).
Encourage the use and establishment of private and public demonstration sites, with special linkage to agri-environment schemes. (Action: CCW, NE, MAFF, WOAD)
Promote conservation and management of Special Areas of Conservation as part of a European network. (Action: CCW, NE, JNCC)
Recommend favourable measures for unimproved calcareous grassland conservation during future negotiations in Europe to revise the Common Agricultural Policy. (Action: DETR, SOAEFD, WOAD)
Review representation of lowland calcareous grasslands in other European countries to determine their extent and status so that the international status of the UK resource can be determined. (Action: CCW, NE, JNCC)
Participate in initiatives to develop and strengthen measures for conservation of the habitat in Europe and elsewhere. (Action: CCW, DETR, NE, JNCC, MAFF, WO, WOAD)
Disseminate information about the UK's experience in conservation of the resource in international literature and conferences and take opportunities to learn from colleagues in Europe and elsewhere. (Action: CCW, DETR, NE, JNCC, MAFF, WO, WOAD)
Research and monitoring
Contribute information to a World Wide Web based catalogue of survey information as a means of improving access to information on lowland calcareous grasslands. (Action: CCW, NE)
Undertake vegetation survey and assessment of unimproved calcareous grasslands in parts of UK with poor survey coverage, using standardised and repeatable methodology. (Action: CCW, EHS, NE)
Formulate quantified and spatially referenced targets to expand the total cover of lowland calcareous grassland of wildlife value across the UK, with particular emphasis on amelioration of habitat fragmentation, by 2005. (Action: CCW, NE)
Review research needs into the conservation and restoration management of the habitat and the integration of this with agriculture, to identify significant gaps in knowledge. Commission and undertake new research as appropriate. (Action: CCW, NE, FC, JNCC, MAFF, WOAD)
Commission and support research on establishment and expansion of species-rich calcareous grassland, covering methodology and landscape ecological components. (Action: CCW, NE, FC JNCC, MAFF, WOAD)
Encourage and support conservation studies on scarce animal and plant taxa associated with unimproved calcareous grasslands with particular relevance to amelioration of damaging impacts from habitat depletion and fragmentation. (Action: CCW, NE, JNCC)
Evaluate the need for impact assessment of the effect of atmospheric nutrient deposition and climate change on community composition, and commission research as appropriate. (Action: CCW, EA, NE, JNCC)
Develop and implement appropriate surveillance and monitoring programmes to assess progress towards action plan targets. (Action: CCW, NE, JNCC, MAFF, SNH, SOAEFD)
Commission marketing studies into ways to promote agricultural products from lowland calcareous grassland. (Action: MAFF, WOAD)
Communications and publicity
Seek opportunities to present lowland grassland conservation in the scientific press and the popular media. (Action: CCW, NE, JNCC)
Encourage appropriate public access for observation and enjoyment of lowland calcareous grassland. (Action: CCW, NE)
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.