Physical and biological status
Maritime cliffs and slopes comprise sloping to vertical faces on the coastline where a break in slope is formed by slippage and/or coastal erosion. There appears to be no generally accepted definition of the minimum height or angle of slope which constitutes a cliff, but the zone defined as cliff-top (also covered in this plan) should extend landward to at least the limit of maritime influence (ie limit of salt spray deposition), which in some exposed situations may continue for up to 500 m inland. This plan may therefore encompass entire islands or headlands, depending on their size. On the seaward side, the plan extends to the limit of the supralittoral zone and so includes the splash zone lichens and other species occupying this habitat. Approximately 4000 km of the UK coastline has been classified as cliff.
Cliff profiles vary with the nature of the rocks forming them and with the geomorphology of the adjoining land. While most maritime cliffs have been formed by coastal erosion, steep slopes falling to the sea in mountainous districts may have been formed long before the sea level reached its present position; in such cases only the lower part of the slope will have been steepened by the sea.
Maritime cliffs can broadly be classified as 'hard cliffs' or 'soft cliffs', though in practice there are a number of intermediate types. Hard cliffs are vertical or steeply sloping; they are inclined to support few higher plants other than on ledges and in crevices or where a break in slope allows soil to accumulate. They tend to be formed of rocks resistant to weathering, such as granite, sandstone and limestone, but can be formed of softer rocks, such as chalk, which erode to a vertical profile. Soft cliffs are formed in less resistant rocks such as shales or in unconsolidated materials such as boulder clay; being unstable they often form less steep slopes and are therefore more easily colonised by vegetation. Soft cliffs are subject to frequent slumping and landslips, particularly where water percolates into the rock and reduces its effective shear strength.
The vegetation of maritime cliff and slopes varies according to several factors: the extent of exposure to wind and salt spray, the chemistry of the underlying rock, the water content and stability of the substrate and, on soft cliffs, the time elapsed since the last movement event. Cliff-top habitats can also be transformed by soil erosion processes.
Vegetation of a strictly maritime nature occurs where exposure to the waves and winds is at its greatest. In the UK, such conditions are found principally on the northern and south-western coasts. In extreme conditions, such as on the Isle of Lewis, saltmarsh vegetation can occur on cliff-tops. In other areas, where cliffs occur adjacent to sand dunes, sufficient wind blown sand can accumulate on the cliff-tops to allow cliff-top dune vegetation to develop (perched dunes). On exposed hard cliffs giving little foothold to higher plants, lichens are often the predominant vegetation. Ledges on such cliffs support a specialised flora with species such as rock samphire Crithmum maritimum and rock sea spurrey Spergularia rupicola in the south and Scots lovage Ligusticum scoticum and in the north. Seabird nesting ledges enriched by guano support a particular community characterised by oraches Atriplex spp and sea beet Beta vulgaris ssp maritima. Maritime grasslands occur on cliffs and slopes in less severely exposed locations; a maritime form of red fescue Festuca rubra is a constant component, together with maritime species such as thrift Armeria maritima, sea plantain Plantago maritima, buck's-horn plantain P. coronopus and sea carrot Daucus carota ssp gummifer. Species of inland grasslands which also commonly occur in maritime grasslands include ribwort plantain Plantago lanceolata, bird's-foot trefoil Lotus corniculatus, common restharrow Ononis repens and several species of grass.
On cliffs and slopes which are more sheltered from the prevailing winds and salt spray, the vegetation communities are more similar to those found inland, and are increasingly influenced by the chemistry of the substrate. Calcareous grassland
communities with a few maritime specialist species occur on sheltered chalk or limestone cliffs. The upper sections and cliff-tops of hard cliffs on acidic rocks may support maritime heaths characterised by heather Calluna vulgaris
. Mobile soft cliffs support a wide range of vegetation from pioneer communities on freshly exposed faces through ruderal and grassland communities to scrub and woodland. Wet flush vegetation commonly occurs on soft cliffs where groundwater issues as seepage.
Maritime cliffs are often significant for their populations of breeding seabirds, many of which are of international importance. Some 70% of the international population of gannet Morus bassanus and important proportions of the European populations of shag Phalacrocorax aristotelis, razorbill Alca torda and guillemot Uria aalge nest colonially on cliff ledges whilst significant populations of Manx shearwater Puffinus puffinus and puffins Fratercula arctica nest in burrows in turf on cliff-tops or slopes. Coastal cliffs are also important for crag nesting species, such as raven Corvus corax and peregine Falco peregrinus, and cliff-top vegetation may provide important feeding grounds for chough Pyrrhocorax pyrrhocorax.
Hard cliffs are widely distributed around the more exposed coasts of the UK, occurring principally in south-west and south-east England (the latter area having the bulk of the 'hard' chalk cliffs), in north-west and south-west Wales, in western and northern Scotland and on the north coast of Northern Ireland. Soft cliffs are more restricted, occurring mainly on the east and central south coasts of England and in Cardigan Bay and north-west Wales. There are also examples on the coasts of Fife and Skye in Scotland and Antrim in Northern Ireland.
Soft cliffs provide important breeding sites for sand martins Riparia riparia
, which burrow into soft faces exposed by recent slippages, but they are particularly important for invertebrates as they provide a suite of conditions which are rarely found together in other habitats. The combination of friable soils, hot substrates and open conditions maintained by cliff slippages offer a continuity of otherwise very restricted microhabitats and these support many rare invertebrates which are confined to such sites. These include the ground beetle Cicindela germanica
, the weevil Baris analis
, the shore bug Saldula arenicola,
and the Glanville fritillary Melitaea cinxia
Seepages, springs and pools are a feature of many soft cliff sites and these provide the wet muds required by many species of solitary bees and wasps for nest building. They also support rich assemblages of other invertebrates including many rare species which are confined to this habitat. These include the craneflies Gonomyia bradleyi and Helius hispanicus, and the water beetle Sphaerius acaroides.
The hard coastal cliffs of west Britain supports a western oceanic invertebrate assemblage of European significance. Important species include the snail Ponentina subvirescens
, weevils such as the highly restricted Cathormiocerus attaphilus
and moths such as Barrett?s marbled coronet Hadena luteago
. Other species are confined to certain rock types. For example, the fiery clearwing Bembecia chrysidiformis
is restricted to the chalk cliffs of Kent and Sussex and the water beetle Ochthebius poweri
occurs predominantly in small seepages on red sandstone cliff faces in south-west England and south Wales.
The supralittoral zone represents the lowest belt of terrestrial vegetation on maritime cliffs and is usually exemplified by a zone of orange and grey maritime lichens. The zone tends to be dominated by species such as Caloplaca marina, Ramalina siliquosa and Verrucaria maura, but may also include uncommon species such as Roccella filiformis and R. phycopsis.
Links with other action plans
The following BAP priority species have significant populations on maritime cliffs:
Current factors affecting the habitat
Erosion . Erosion is a highly significant factor in soft cliffs. High rates of erosion do not imply a loss of the cliff resource, either in geological or biological terms. Cliff face communities are able to retreat with the cliff line, and erosion is vital for constantly renewing geological exposures and recycling the botanical succession on soft cliffs. However, cliff-top vegetation may be destroyed where it is squeezed between a receding cliff face and cultivated land. Cliff erosion in many places provides an essential supply of sediment to coasts lying down-drift of the cliffs.
Coastal protection . Coastal protection systems have been built on many soft cliff coasts in order to slow or stop the rate of erosion and thus protect capital assets behind the cliff line. Cliff faces may also be re-profiled and sown with hardy grasses of little value for nature conservation. All such works have the effect of stabilising the cliff face, resulting in geological exposures being obscured, bare soil and early pioneer stages being progressively overgrown, and wet flushes drying out. A MAFF survey in 1994 identified over 90 km of new cliff protection works likely to be needed in the next 10 years, resulting in a potential loss of 36% of the remaining soft cliff resource. Additional effects of such defences include both accelerated erosion and sediment starvation at coastal sites down-drift of defended sites. It has been estimated that sediment inputs may have declined by as much as 50% over the past 100 years due to cliff protection works.
Built development . There have been many instances in the UK of urban or industrial development and holiday accommodation being built too close to cliff-tops. Where the cliffs are subsequently discovered to be eroding, there is often political pressure to build the type of defensive works described above. Built development also prevents cliff-top biological communities from retreating in response to cliff erosion, subjecting them to a form of 'coastal squeeze'.
Agriculture . In traditional low-intensity grazing systems, livestock were grazed on cliff grasslands where they maintained open maritime grassland vegetation. Post-war intensification of agriculture has led to maritime grassland on more level terrain being ploughed out, while that on sloping ground has been abandoned and, where not maintained by exposure, is frequently overgrown by scrub. Localised eutrophication can be caused by fertiliser run-off from arable land above and this encourages coarse, vigorous 'weed' species at the expense of the maritime species. Agricultural land drains discharging on the cliff face may cause local acceleration of erosion.
Recreational use . The siting of holiday accommodation on cliff-tops not only reduces the landscape value of a site, but can also cause heavy localised erosion and disturbance to nesting birds. An increase in the number of walkers and dogs along some coastal footpaths has increased livestock worrying and even losses and forced a number of farmers to remove their stock from these sites. Consequently, some of the sites are now suffering from a lack of appropriate grazing, and scrub encroachment is likely to become a problem.
Introduced species . Predators, such as cats and rats, can have a significant impact on populations of cliff or burrow nesting seabirds, particularly on island sites. Also the spread of certain alien, invasive plants, especially members of the flowering plant family Aizoaceae such as the hottentot fig Carpobrotus edulis, can have a devastating impacton indigenous maritime plant communities.
A high proportion of the hard cliff coast in England has been notified as SSSIs, and in areas such as the south-west of England almost the whole cliffed coast has been notified. Notification of soft cliffs has been less extensive, but areas such as north-west Norfolk and the Isle of Wight have a high proportion of their soft cliffs notified. In Wales approximately half of the total maritime cliff resource has been notified as SSSIs, but as yet only a small proportion has been notified as ASSIs in Northern Ireland. Nine lengths of coastline in the UK have been nominated as 'Vegetated sea cliffs of the Atlantic and Baltic coasts' candidate Special Areas of Conservation (SAC) under the EC Habitats Directive for their cliff features (two of which include substantial representation of soft cliffs). Under the EC Birds Directive, 38 Special Protection Areas (SPA) in the UK have been designated which include cliff sites - these comprise 30 sites in Scotland, 5 in Wales, 2 in England, and 1 in Northern Ireland.
Management, research and guidance
The UK Government has set out its commitment to sustainable management of the coast in a number of publications. These include the DETR Policy Guidelines for the Coast and Planning Policy Guidance - Coastal Planning (PPG 20), the Scottish Office Coastal Planning (NPPG 13), and the Welsh Office Technical Advice Note 14 Coastal Planning. The DoNEI Planning Strategy for Rural Northern Ireland has provisions relating to development, access and conservation of the coast. MAFF and the Welsh Office have also produced a Strategy for Flood and Coastal Defence in England and Wales and the DETR has produced Coastal Zone Management - Towards Best Practice.
The DETR Coastal Forum was set up in 1994; similar fora have recently been initiated in Scotland and Wales. Certain coastal fora have also been set up by the country nature conservation agencies. These include the Estuaries Initiative, in England, Focus on Firths in Scotland, and in Wales an independent partnership of coastal practitioners (Arfordir). More general countryside management initiatives (Tir Cymen and the Habitats Scheme in Wales and Countryside Stewardship in England) offer options applicable to grazing management of cliff grassland . Recent figures show that 104 ha of cliff grassland had been entered into Tir Cymen, and 184 ha in to the Habitats Scheme, but no separate figures are available for cliff land entered into Countryside Stewardship. The Tir Cymen pilot scheme which was restricted to just a few areas in Wales has been superseded by an all-Wales agri-environment scheme (Tir Gofal).
Over 700 km of cliff coastline in England, Wales and Northern Ireland is owned by the National Trust, who are actively reinstating grazing on many of these properties. Other non-governmental organisations, such as RSPB and the Wildlife Trusts, own or manage a number of other important maritime cliff sites. A large proportion of the cliff coast of south-west England and western Wales is within designated Heritage Coasts, while three National Parks (North York Moors, Exmoor and Pembrokeshire Coast) include cliffed coastlines. A number of cliff coasts in western Scotland are within National Scenic Areas. These designated areas often have the benefit of a warden/ranger service which encourages appropriate management and control of damaging activities, and provides interpretative and educational services.
Shoreline Management Plans and the work of their associated Coastal Groups will provide one of the main mechanisms for ensuring that the requirements of this plan are carried foreward.
A Sea Cliff Management Handbook was produced jointly by the University of Lancaster, JNCC and the National Trust in 1991, and in 1998 The National Trust produced a report entitled Grazing Sea Cliffs and Dunes for Nature Conservation.
Action plan objectives and targets
Seek to maintain the existing maritime cliff resource of cliff-top and slope habitat, of about 4000 km.
Maintain wherever possible free functioning of coastal physical processes acting on maritime cliff and slope habitats.
Retain the amount of maritime cliff and slope habitats unaffected by coastal defence and other engineering works.
Where possible increase the amount of maritime cliff and slope habitats unaffected by coastal defence and other engineering works.
Increase the area of cliff-top semi-natural habitats by at least 500 ha over the next 20 years.
Improve by appropriate management the quality of at least 30% of the maritime cliff and slope habitats, including cliff-top vegetation, by 2010.
Improve by appropriate management the quality of as much as possible of the remaining maritime cliff and slope habitats, including cliff-top vegetation, by 2015.
Proposed actions with lead agencies
Policy and legislation
Promote sea defence and coastal protection policies which encourage the free functioning of the coastal physical processes of maritime cliffs wherever possible. (ACTION: DANI, DoE(NI), EA, LAs, MAFF, NAW, SE)
In the light of research findings, give consideration to how planning policy might discourage new built development within appropriate buffer zones in the vicinity of retreating cliff-tops. (ACTION: CCE, DETR, DoE(NI), EHS, NE, LAs, NAW, SE, SNH)
Look into the feasibility of developing provisions within the planning systems to encourage the re-siting of housing and holiday developments which are vulnerable to cliff erosion. This will be initiated on completion of the research outlined in 5.5.3. (ACTION: DETR, DoE(NI), NAW, SE)
Where appropriate promote agri-environment schemes which encourage management and restoration of maritime grassland, heathland and other cliff-top habitats. (ACTION: CCW, DANI, MAFF, NAW, SE, SNH)
Site safeguard and management
By 2004 apply conservation designations to all remaining areas of maritime cliff and slopes which meet national or international criteria and ensure appropriate management of all designated sites. (ACTION: CCW, EHS, NE, SNH)
Encourage a presumption against stabilisation of any cliff face except where human life, or important natural or man-made assets, are at risk. (ACTION: DANI, DoE(NI), LAs, MAFF, NAW, SE)
Where stabilisation of a cliff face is necessary (as defined in 5.2.2), ensure adequate mitigation and/or compensation to maintain the overall quantity and quality of maritime cliff and slopes habitat. (ACTION: CCW, DANI, DoE(NI), EHS, NE, LAs, MAFF, NAW, SE, SNH)
Encourage the increased use of soft (eg foreshore recharge) rather than hard engineering techniques where some degree of cliff stabilisation is essential. (ACTION: MAFF, DANI, DETR, DoE(NI), LAs, NAW, SE)
Consider non-replacement of coastal cliff defences which have come to the end of their useful life. (ACTION: MAFF, DANI, DETR, DoE(NI), LAs, NAW, SE)
Promote the management of maritime grassland and heath habitats by scrub control and grazing where appropriate, through relevant agri-environment schemes and management agreements. (ACTION: CCW, DANI, EHS, NE, MAFF, NAW, SE, SNH)
Conduct operations to remove rats, cats or other introduced predators affecting breeding seabirds on maritime cliff and slope sites, identified by ‘Seabird 2000' and other surveys. (ACTION: CCW, EHS, NE, SNH)
Assess the impact of agricultural land drainage on maritime cliffs and slopes, especially in SACs, and carry out a review of the effectiveness of the current consents procedure. (ACTION: MAFF)
Encourage by 2002 the adoption of policies and practices in the engineering management of soft cliffs which are sympathetic to the nature conservation interest, by preparing and disseminating ‘best practice’ guidance material. (ACTION: DANI, EA, MAFF, NAW, SE)
Encourage by 2002 appropriate habitat management of maritime cliff and slope habitats by preparing and disseminating ‘best practice’ guidance material. (ACTION: CCW, EHS, NE, SNH)
Promote the exchange of information on maritime cliff ecology and management among European maritime states through the European Union for Coastal Conservation and Eurosite. (ACTION: CCW, EHS, NE, JNCC, SNH)
Research and monitoring
By 2003 commission a literature review and full survey of the maritime cliff and slope resource in the UK to assess its relative conservation value, how much can be improved by alternative management, and to what extend it is affected by coastal defence and engineering works. (ACTION: CCW, EHS, NE, JNCC, SNH)
By 2003 commission a study to identify areas in the UK suitable for the re-creation of maritime grasslands and heathlands. (ACTION: CCW, EHS, NE, JNCC, SNH)
By 2003 commission a study to identify possible coastal and sea defence strategies that may be more sympathetic to the nature conservation interests of maritime cliffs, and identify stretches of coastline where such sympathetic modifications are feasible. (ACTION: DoE(NI), EA, MAFF, NAW, SE)
By 2003 implement a baseline study to determine the extent and quality of the maritime cliff and slope resource in the UK in order to enable the effective assessment of progress towards meeting the objectives of this plan. (ACTION: CCW, EHS, NE, JNCC, SNH)
By 2003 complete an assessment of the maritime cliff sites in the UK where the native flora and fauna is being affected by introduced species. (ACTION: CCW, EHS, NE, SNH)
Carry out an evaluation of cliff erosion and how its contribution to the marine sediment budget could be affecting other key habitats. (ACTION: MAFF)
Carry out an assessment of how the conservation interest of maritime cliffs may be affected by climate change. (ACTION: CCW, EHS, NE, MAFF, SNH)
By 2003, in order to meet objective 4.3, develop an inventory of coastal defences that impact on maritime cliff and slope habitats and identify the most appropriate defences for removal. (ACTION: CCW, EA, EHS, NE, SNH)
Communications and publicity
Raise public awareness of the mobile nature of soft cliffs and the value of maintaining unrestricted coastal processes. (ACTION: CCW, EHS, NE, SNH)
Promote awareness of the implications of the policies outlined in this plan among coastal Local Authorities, and ensure that the relevant details are incorporated into coastal zone management plans including Shoreline Management Plans. (ACTION: CCW, DETR, EHS, NE, MAFF, NAW, SE, SNH)
Raise public awareness of the potential damage that can be inflicted on the native flora and fauna of maritime cliffs by introduced species. (ACTION: CCW, EHS, NE, SNH)
Carter, R.W.G. 1988. Coastal Environments - an introduction to the physical, ecological and cultural systems of coastlines. Academic Press.
Malloch, A.J.C. 1972. Salt-spray deposition on the maritime cliffs of the Lizard peninsula. Journal of Ecology, 60 , 103-112.
Ministry of Agriculture, Fisheries and Food. Code of Practice on Environmental Procedures for Flood Defence Operating Authorities. MAFF PB 2906.
Ministry of Agriculture, Fisheries and Food. 1993. A strategy for flood and coastal defence in England and Wales. MAFF PB 1471.
Ministry of Agriculture, Fisheries and Food. 1994. The investigation and management of soft rock cliffs in England and Wales. Report by Rendel Geotechnics (Contract no. CSA 2681).
Ministry of Agriculture, Fisheries and Food. 1995. Shoreline Management Plans: A guide for coastal defence authorities. MAFF PB 2197.
Mitchley, J. & Malloch, A.J.C. 1991. Sea Cliff Management Handbook. University of Lancaster and Joint Nature Conservation Committee in association with the National Trust. Published by the Institute of Environmental and Biological Sciences, University of Lancaster.
Oates, M., Harvey, H.J. & Glendell, M. eds. 1998. Grazing Sea Cliffs and Dunes for Nature Conservation. The National Trust, Estates Department, Cirencester.
Preston, C.D. 1988. The Aizoaceae naturalised in the British Isles. Watsonia, 17 , 217-245.
Pye, K. & French, P.W. 1992. Targets for coastal habitat re-creation. Unpublished report to English Nature, Peterborough (F72-04-22/ES22).
Rodwell, J.S. (in prep). British Plant Communities. Volume 5: Maritime and weed communities. Cambridge University Press, Cambridge.