Lowland Heathland and Dry Acid Grassland - Habitat Action Plan

Definition of lowland acid grassland is problematical but here it is defined as both enclosed and unenclosed acid grassland normally below c.300m. It is characterised by a range of grasses and herbs, and in East Anglia, the typical community is NVC U1 comprising sheep's-fescue Festuca ovina, common bent Agrostis capillaris and sheep's sorrel Rumex acetosella. Other species may include wavy hair-grass Deschampsia flexuosa, heath bedstraw Galium saxatile and tormentil Potentilla erecta. It occurs as an integral part of lowland heath landscapes, often forming an intricate mosaic with dwarf shrub heath. As a result it may be difficult to calculate separate areas of each community.

Heather Gorse
(Photo credit: Graeme Cresswell)
Ref 1/H6 Habitat Action Plan 6
Plan Author: Norfolk County Council
Plan Co-ordinator: Norfolk County Council
Previous versions 31 December 1998
April 2004
Current version 17 November 2011
 

Action Plan Summary

Current Status

Definition

  • The UK BAP identifies heathland as consisting of “an ericaceous layer of varying heights and structures, some areas of scattered trees and scrub, areas of bare ground, gorse, wet heaths, bogs and open water”. In Norfolk, heathland is much more of a mosaic, with acid grassland and bracken often being significant elements. Even more distinctive are the heaths of the Brecks which include chalk grassland and little or no heather.
    In East Anglia, the typical lowland acid grassland community is NVC U1, comprising sheep’s-fescue Festuca ovina, common bent Agrostis capillaris and sheep’s sorrel Rumex acetosella. Other species may include wavy hair-grass Deschampsia flexuosa, heath bedstraw Galium saxatile and tormentil Potentilla erecta.

National Status

  • In England, only a sixth of the heathland present in 1800 now remains. The UK has about 95,000 ha of lowland heathland (58,000 ha of which are in England) representing about 20% of the international total of this habitat.
  • As with other lowland semi-natural grassland types, acid grassland underwent substantial declines in the 20th century. Although there are no figures available on the current rate of loss, it is thought to be slowing. The decline is primarily the result of under-management, specifically under-grazing and abandonment. In Norfolk, afforestation has also been a significant factor in heathland decline (although perversely, in Breckland, the soil disturbance associated with forestry management may have helped to sustain the very high levels of biodiversity - particularly invertebrates - that the area supports today.)
  • Cover data for lowland acid grassland across the UK for the full altitudinal range are not currently available. Stands remote from the upland fringe, which are the primary focus of conservation attention, are now of restricted occurrence and it is estimated that less than 30,000 ha now remain in the UK. Important concentrations occur in Breckland, the New Forest, Dorset, Suffolk Sandlings, the Weald, Dungeness, the coasts of south-west England and the Welsh and English border hills of Powys and Shropshire. Scotland is estimated to have less than 5,000 ha and much of this is likely to be on the upland fringe.

Norfolk Status

  • It has been estimated that the extent of heathland (taking a wide definition) in 1797 was 30,500ha. The estimate of that existing today is 7,787ha1, of which approximately 3,610ha has been mapped as heathland and 4176ha as dry acid grassland. This represents a decline of 75 per cent. However, the Stanford Training Area, which has a large and important area of largely relatively recent grass heath of about 3,116ha, represents 40 per cent of this figure. Over 80 percent (6,472ha) of Norfolk’s existing heathland and acid grassland is covered by Site of Special Scientific Interest designation. Approximately 538ha are in County Wildlife Sites.
  • Priority BAP bird species associated with Norfolk’s heaths include nightjar, woodlark, red-backed shrike, stone curlew, skylark, grey partridge and linnet. Priority invertebrates include silver-studded blue butterfly solitary wasp (Cerceris quinquefasciata) and two ground beetles (Harpalus H. froelichii and Ophonus laticollis). Other priority BAP species associated with heaths include tower mustard, nail fungus, starry breck lichen, pillwort and natterjack toad.
  • The Breckland Biodiversity Audit (Dolman, Panter and Mossman, 2010) has highlighted the importance of structural heterogeneity and active ecological processes for integrating the requirements of important BAP species; i.e., heaths are systems which function best when they support the maximum diversity of conditions across the habitat, including bare ground, and are often best maintained with a high level of soil disturbance.

Current factors causing loss or decline in Norfolk

  • Encroachment of trees, shrubs and bracken due to abandonment of traditional management such as grazing, fuelwood gathering and to some extent, controlled burning. These factors affect most sites, including even SSSIs.
  • Declining availability of water for wetland areas within heaths.
  • Uncontrolled fires in some areas (eg, Mousehold Heath), particularly in summer.
  • Atmospheric deposition of nitrogen.
  • Development of non-statutory sites.
  • The access provision in the CROW Act may act as a disincentive to heathland creation in some situations.
  • Losses to agriculture have been a major factor in the past. With the recent introduction of current EIA regulations, it is hoped that these losses have ceased.

back to top

Current Action in Norfolk

The Brecks

  • The Breckland Biodiversity Audit was a collaborative venture headed by a team from UEA, to review the status of Breckland biodiversity and the evidence basis for its management. Nearly one million biological records were collated during the study, from a wide variety of organisations and individual recorders. Information about the ecological processes required by individual species was also gathered, along with information about the management of Breckland sites. The audit demonstrated the outstanding importance of Breckland for UK biodiversity. Some 12,845 species were recorded, including 2,149 species of conservation concern. The audit also showed that 28 per cent of all UK priority BAP species occur in Breckland.
  • Plantlife is carrying out a Grantscape-funded project in the Brecks. This involves micro-habitat management trials, looking at a variety of disturbance factors and processes, concentrating on creating early-successional habitats. The overall aims of the project include addressing the decline in plant species particular to the Brecks, establishing effective methods of managing small-scale habitats and developing a landscape-scale plant conservation strategy for the Brecks.
  • Butterfly Conservation’s project, “Restoration of Norfolk Brecks Heathlands for Threatened Butterflies and Moths”, is focusing on nine BAP species, and being carried out on the Norfolk side of the Brecks.
  • The Forestry Commission has been working to integrate the recommendations of the Breckland Biodiversity Audit into its management of Thetford Forest. This has included widening the forest rides and promoting greater soil disturbance.
  • The University of East Anglia has been carrying out research into invertebrate responses to experimental ride management in Thetford Forest.

Norfolk Excluding The Brecks

  • The Norfolk Wildlife Trust has been involved in a major heathland restoration project at Grimston Warren in north-west Norfolk, funded by a variety of organisations including English Nature (now Natural England), the SITA Trust, WREN, the John Jarrold Trust, Norfolk County Council, and HLS. Management has included tree felling, brash collection, stump grinding, litter removal and grazing by Dartmoor Ponies. Guided walks have been held to promote the work to local people and NWT supporters, and articles have appeared in NWT’s magazine Tern and the local press. Breeding reports for Grimston Warren now include nightjar, woodlark, black darter dragonfly and turtle dove, among others.
  • Following consultation with Norfolk Landscape Archaeology and local herpetologists, and with the support of the Holt Lowes Trustees, NWT embarked on a major restoration project at Holt Lowes in 2010/11, funded through Higher Level Stewardship. The project has included the clearance of 15ha of mature scrub and the removal offsite of approximately 15,000 cubic metres of humus. The aim is to restore open heathland on this important SSSI and SAC valley fen site. Because of the site’s reptile and archaeological interest, machine movements have been carefully controlled, with extensive areas being cleared by hand and other areas left unscraped.
  • NWT’s Hidden Heaths Project aims to deliver BAP targets for non-statutory heathland sites in Norfolk by raising the profile of heaths for wildlife, increasing public interest in heaths and by bringing more sites into appropriate management.
  • NWT’s Heathland CWS Audit is gathering information on 68 sites with a heathland or acid grassland component for which there is no current condition assessment. Of the 96 sites assessed so far, 46 were deemed to be declining, neglected or damaged; 24 were deemed to be improving, and 21 were felt to be in reasonable or good/excellent condition. The status of five sites remains unknown.
  • Substantial areas of former mineral sites have been restored to heathland/acid grassland, particularly at Leziate quarries in west Norfolk. Some of these sites are now of a high biodiversity value.
  • A new management plan for Mousehold Heath has been prepared, covering the period 2008-2013. This aims to maintain, enhance, increase and join up areas of lowland heath vegetation, control the encroachment of trees and bracken, maintain and enhance acid grassland areas and increase public understanding of issues related to the conservation of lowland heaths.
  • Management of Salthouse and Kelling Heaths is continuing under a Higher Level Stewardship scheme. Recent work has included fencing 2ha of heathland to allow grazing by sheep to maintain archaeological features and control birch re-growth. A second fencing project at Salthouse Heath has been implemented to exclude deer from important nightingale nesting areas. The dense scrub and understorey formerly used by the birds is disappearing as a result of canopy closure and grazing of the understory. These areas are being fenced and selective thinning of birch is taking place to encourage the understory to re-establish. On Kelling Heath, bare ground is being created to benefit heathland invertebrate species, particularly silver-studded blue butterfly and the associated black ants Lasius niger.
  • Information about Kelling Heath is being compiled by local naturalists and can be accessed at: http://www.kellingheathwildlife.org.uk
  • The Forestry Commission has established a link between Marsham and Buxton heaths, by clearing a corridor of conifers between the two sites.

back to top

Action Plan Objectives and Proposed Targets

National Targets (Baseline 2005)

Heathland
  • Maintain the current extent of all existing lowland heathland (94,788 ha - no net loss of habitat).
  • Maintain the area of lowland heathland currently in favourable condition.
  • Improve the condition of lowland heathland on sites currently in unfavourable condition (12,762 ha).
  • Increase the extent of lowland heathland by 7,600 ha by 2015.
  • Increase the number of heathland patches over 30 ha from 10% of the total resource to 50% by 2030.
Lowland Dry Acid Grassland
  • Maintain the current extent of lowland dry acid grassland in the UK (61,646 ha - no net loss of habitat).
  • Maintain at least the current condition of lowland dry acid grassland.
  • Achieve favourable or recovering condition for 34,745 ha of lowland dry acid grassland by 2015.
  • Restore 597 ha of lowland dry acid grassland from semi-improved or neglected grassland, which no longer meets the priority habitat definition by 2015.
  • Re-establish 411 ha of grassland of wildlife value from arable or improved grassland by 2015.
  • 312 ha (75%) of re-established area to be adjacent to existing lowland dry acid grassland or other semi-natural habitat by 2015.
  • 208 ha (50%) of re-established area to contribute to resultant habitat patches of 6 ha or more of lowland dry acid grassland by 2015. Wherever practicable, bigger patches should be created.
East of England Targets, 1996-2015
  • Restore 260 hectares of lowland heath or dry acid grassland from semi-improved or neglected grassland.
  • Re-establish 1,400 hectares of heath or grassland of wildlife value from arable or improved grassland and increase the extent of lowland heathland.

Norfolk Targets and Objectives

Objectives
  • To maintain 100% of the current lowland heathland and acid grassland in the county (no net loss of habitat).
  • To maintain the condition of those sites already in favourable management, by ensuring the continuation of existing management regimes.
  • To identify and rehabilitate priority areas which are not currently in favourable condition.
  • To restore and create new heathland and acid grassland at priority sites. Particular emphasis should be placed on enlarging, buffering and re-connecting sites, in line with the recommendations of the Norfolk ecological network mapping project.

back to top