Habitat Action Plan

Coastal sand dunes develop where there is an adequate supply of sand (sediment within the size range 0.2 to 2.0 mm) in the intertidal zone and where onshore winds are prevalent. The critical factor is the presence of a sufficiently large beach plain whose surface dries out between high tides. The dry sand is then blown landwards and deposited above high water mark, where it is trapped by specialised dune-building grasses which grow up through successive layers of deposited sand.

Sand dunes form in relatively exposed locations, and in a number of physiographic situations. The most common are bay dunes , where a limited sand supply is trapped between two headlands; spit dunes , which form as sandy promontories at the mouths of estuaries; and hindshore dunes , which occur in the most exposed locations where large quantities of sand are driven some distance inland, over a low-lying hinterland. This last type forms the largest dune systems in the UK. Less common types are: ness dunes , which build out from the coast; dunes on offshore islands , which are often superimposed on a base of other material such as shingle; climbing dunes where sand is blown up on to high ground adjacent to the beach; and tombolos , where a neck of sand is deposited between two islands or between a promontory and an island.

Sand dune vegetation forms a number of zones, which are related to the time elapsed since the sand was deposited, the degree of stability which it has attained, and the local hydrological conditions. Embryonic and mobile dunes occur mainly on the seaward side of a dune system where sand deposition is occurring and occasionally further inland in blow-outs. They support very few plant species, the most characteristic being marram grass Ammophila arenaria. Semi-fixed dunes occur where the rate of sand accretion has slowed but the surface is still predominantly bare sand; marram is still common but there is an increasing number of other species. Fixed dune grassland forms largely closed swards where accretion is no longer significant, the surface is stabilised and some soil development has taken place. Calcareous fixed dunes support a particularly wide range of plant species. On dunes which have become acidified by leaching, acid dune grassland or dune heaths develop. Dune heaths are usually dominated by heather Calluna vulgaris. Acidic dunes which are heavily grazed by rabbits may support lichen communities. Dune slack vegetation occurs in wet depressions between dune ridges; it is often characterised by creeping willow Salix repens ssp argentea and a number of mosses. Fixed dunes and dune heath are particularly threatened habitats and are regarded as priorities under the EC Habitats Directive.

The fixed dune communities mentioned above are, or have been, maintained by grazing, whether by domestic stock or by rabbits. In their absence, the succession proceeds to rough grass and scrub. Dune scrub can include several species but only one of them, sea buckthorn Hippophaë rhamnoides, is largely confined to dunes; it is native to eastern England and south-east Scotland and has been widely introduced elsewhere, where its very invasive nature can cause problems. Wetter parts of dune systems may become colonised by sallows Salix spp, birches Betula spp or alder Alnus glutinosa.

Sand dune communities vary geographically: lyme grass Leymus arenarius is increasingly common in northern Britain, growing alongside marram grass in mobile dunes; wild thyme Thymus polytrichus is characteristic of south-west England; and common juniper Juniperus communis occurs on dunes only in two locations, both in Scotland.

Dune grassland and dune slacks, especially on the more calcareous systems, support a wide variety of colourful flowering plants, including a number of species of orchid. Sand dune systems are also very rich in invertebrates, including butterflies, moths and burrowing bees and wasps.

The Sand Dune Survey of Great Britain (1993-1995) gives the total area of sand dunes as 11,897 ha in England and 8101 ha in Wales. The ongoing Sand Dune Vegetation Survey of Scotland indicates that there may be as much as 48,000 ha of dune and machair in Scotland, of which 33,000 ha is dune. There are approximately 3000 ha of dunes in Northern Ireland. Major dune systems are widely distributed within the UK, being found on all English coasts except the English Channel (other than Sandwich Bay) and the Thames Estuary. They occur on the north and south coasts of Wales and in the northern part of Cardigan Bay. In Scotland dunes are found on all coasts but are less frequent in the north-west and in Shetland; they are particularly extensive in the Western Isles and Inner Hebrides where they are associated with machair. In Northern Ireland the largest dune systems are located along the north and south-east coasts.

The machair habitat action plan is closely related to this plan with regard to western Scotland, where the two habitats frequently occur adjacent to each other, and similar objectives apply to both. The lowland heathland action plan provides objectives and actions which are also relevant to heaths on sand dunes.

The following BAP priority species have significant populations on sand dunes:

• Bright wave moth Idaea ochrata cantiana
• Spider wasp Evagetes pectinipes
• Tiger beetle Cicindela hybrida
• Ground beetle Panagaeus crux-major
• Dune gentian Gentianella uliginosa
• Fen orchid  Liparis loeselii
• href="UKPlans.aspx?ID=167">Dune thread moss& Bryum mamillatum
• href="UKPlans.aspx?ID=168">Long leaved thread moss Bryum neodamense
• href="UKPlans.aspx?ID=171">Moss Bryum warneum
• href="UKPlans.aspx?ID=509">Petalwort Petalophyllum ralfsii

Erosion and progradation. Unless artificially constrained, the seaward edges of sand dunes can be a highly mobile feature, though there is a natural trend to greater stability further inland. Very few dune systems are in overall equilibrium, and a majority of those in the UK demonstrate net erosion rather than net progradation; insufficient sand supply is frequently the underlying cause. There is no particular geographical distribution of either trend, both normally being present along any one stretch of coastline, and often within individual sites. Changes may be cyclical, both seasonally and over longer periods of time. Landward movement of mobile dunes often entails loss of fixed dune and dune heath habitat, as the latter are usually stable, or retreat may be impeded by development; in a few cases dune systems may move inland where not artificially constrained. The net loss of dune habitat in England to erosion has been estimated as not more than 2% of the resource over the next 20 years.

Falling water tables. Dune slacks support characteristic communities dependent on a seasonally high water table, including the formation of temporary or even permanent ponds. There may be considerable variation in the behaviour of the water table from year to year, resulting in a stressed ecosystem where only specialised species can survive. However in some dune systems with important slacks, a long term fall in the water table has led to loss of the specialist slack flora and invasion by coarse vegetation and scrub. While unusually dry summers may have contributed to this problem, the long-term causes are believed to be local extraction of water and/or drainage of adjacent land used for agriculture or housing.

Grazing. In the absence of human interference, most stable dunes, with the exception of those experiencing severe exposure, would develop into scrub and woodland. The preponderance of grassland and heath vegetation on British dunes is due to a long history of grazing by livestock. Continued grazing is normally necessary to maintain the typical fixed dune communities, but over-grazing, particularly when combined with the provision of imported feedstuffs, can have damaging effects. A more widespread problem is under-grazing, leading to invasion by coarse grasses and scrub, though rabbits are locally effective in maintaining a short turf. Parts of some stabilised dune systems have been entirely converted to agricultural use, resulting in almost total loss of the conservation interest.

Recreation. Recreation is a major land use on sand dunes. Many dune systems are used extensively by holiday-makers, mostly on foot but also for parking cars and in some cases for driving four-wheel-drive vehicles or motorcycles. Moderate pressure by pedestrians may cause little damage, and may even help to counteract the effects of abandonment of grazing. However, excessive pedestrian use, as on routes between car parks and beaches, and vehicular use in particular, have caused unacceptable erosion on many dune sites. Many dune systems also support one or more golf courses. Here much of the original vegetation may be retained in the rough, but the communities of the fairways, and particularly the greens and tees, are often severely modified by mowing, fertilising and re-seeding. Fragmentation of dune systems by golf courses makes grazing management much more difficult.

Sea defence and stabilisation. Many dune systems are affected by sea defence works or artificial stabilisation measures such as sand fencing and marram planting. These practices are particularly prevalent on the more developed coastlines where drifting sand may be perceived as a threat to urban or holiday developments. While carefully applied dune management measures can help to counteract severe erosion which may threaten the existence of a dune, engineered defence systems usually reduce the biodiversity inherent in the natural dynamism of dune systems, and may cause sediment starvation down-drift. UK dunes as a whole suffer from over-stabilisation and poor representation of the mobile phases.

Beach management. The seaward accretion of dune systems takes place through the accumulation of wind-blown sand caught by plants or debris along the driftline; the initial accumulations are colonised by pioneer plant species and form embryo dunes. On some heavily used beaches this process is inhibited by pressure of pedestrian or vehicular traffic, or by beach cleaning using mechanical methods, where the organic nuclei for sand deposition may be removed. These factors may remove the minor obstacles which would catch the sand initially, or destroy the embryo dunes at an early stage in their formation. In either case a dune system in a location where the physical conditions exist for accretion may actually be static or eroding.

Forestry. Afforestation of dunes is not as prevalent in Britain as it is in parts of continental Europe, but in a few locations it has had a major effect on large areas of dune landscape. Some sites hold large conifer plantations which have the effect of suppressing the dune vegetation communities and lowering the water table. However, both routine fellings and permanent removal of conifers have shown that vegetation close to the original can be restored in a relatively short time.

Military use. During the Second World War the majority of dune systems were used for the construction of defensive installations, for military training or both. The resultant widespread erosion had a severe effect on dune vegetation which has since been reversed by protective measures and natural recovery. A significant number of major dune systems, particularly in Scotland, are still used for military training, but fortunately most retain good dune habitat. Military use can be beneficial in restricting other activities or developments.

Ownership. A substantial proportion of the UK coast is in the ownership of Government Departments/Agencies or voluntary conservation bodies, though the degree of influence over management is variable due to legal complexities.

Other human influences. Sand dunes have also been affected in the past by housing developments, industrial development, waste tips on or adjacent to them, fly tipping and sand extraction. Indirect effects on dunes include atmospheric nutrient deposition, and coastal squeeze due to rising sea levels and increased storminess. The potential for dredging and marine aggregate extraction, through the disruption of coastal processes, to have cumulative and long-term effects on sand dunes is an area for further investigation.

A large proportion of the sand dune resource in the UK is designated as SSSI, or ASSI in Northern Ireland. Of 121 sites in England surveyed between 1987 and 1990, 56 were wholly or almost wholly designated, and another 23 were partly designated. In a partial survey of Scottish dunes, 24 of the 34 sites surveyed were designated as SSSI. In Wales, 24 of the 49 sites surveyed were designated as SSSI. In Northern Ireland 10 of the 26 sites surveyed were designated as ASSIs with a further 4 sites as pASSIs.Twenty one sites in the UK have been selected as candidate SACs under the EC Habitats Directive for their sand dune features.

The UK Government has set out its commitment to sustainable management of the coast in a number of publications. These include DETR's Policy Guidelines for the Coast and Planning Policy Guidance - Coastal Planning (PPG 20), SO?s Coastal Planning (NPPG 13), and WO's Coastal Planning (Technical Advice Note 14). DoE(NI)?s Planning Strategy for Rural Northern Ireland has provisions relating to development, access and conservation of the coast. MAFF and NAW have also produced a Strategy for Flood and Coastal Defence in England and Wales and DETR has produced Coastal Zone Management - Towards Best Practice. Shoreline Management Plans, which have so far been compiled for only part of the UK, are likely to play an increasingly important role in the future management of soft coasts.

DETR's Coastal Forum was set up in 1994; similar fora have recently been initiated in Scotland and Wales, and one is expected shortly in Northern Ireland. The country nature conservation agencies have their own coastal fora or initiatives (Estuaries Initiative, England, and Focus on Firths, Scotland). In Wales a partnership of coastal practitioners (Afordir) has been established. More general countryside management initiatives offer sand dune management options. Between 1993 (when separate records for sand dunes began) and the end of 1998, 397 ha were entered into Countryside Stewardship in England.

The EU LIFE programme Implementing strategies in Irish beach and dune management: involvement in sustainable coastal development forms part of the EU demonstration programme on integrated coastal zone management.

Many NNRs, SSSIs and ASSIs with fixed dune vegetation are managed by grazing with domestic livestock. Prominent examples include the Sefton Coast and Sandscale Haws in England, Tentsmuir in Fife, Newborough in Wales and Murlough Dunes in Northern Ireland. Many of the larger and/or more heavily visited dune sites are managed as nature reserves or country parks, or fall within designated Heritage Coasts; such sites usually have the benefit of a warden/ranger service providing positive conservation management such as scrub control, control of damaging activities and interpretive and educational services. Many sand dune sites benefit from protective ownership by NGOs, such as the National Trust. CCW has initiated a draft Site Management Framework in order to rationalise sand dune management on a country-wide basis. There have been recent initiatives to encourage management of golf courses on sand dunes in a way that is sympathetic to the conservation interest. A major dune management initiative financed by the EU LIFE project is currently under way on the Sefton Coast.

The networks of the European Union for Coastal Conservation and Eurosite have helped to promote a number of international conferences and field meetings on dune management in recent years, resulting in valuable exchanges of views and experience among dune managers from maritime nations. The European Golf Association Ecology Unit has promoted sympathetic management of dune golf links.

The Sand Dune Survey of Great Britain was initiated in 1987 and provides information on the vegetation and current management of all significant dune systems. Full results have been published for England and Wales, while the Scottish survey is currently being completed and final results will be published in 2000.

The successful implementation of this habitat action plan will have resource implications for both the public and private sectors. The data in the table below provide an estimate of the current expenditure on the habitat, primarily through agri-environment 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 time periods is also given. Three-quarters of the additional resources are likely to fall to the public sector.

Dargie, T.C.D. 1993. Sand dune vegetation survey of Great Britain: a national inventory. Part 2: Scotland. Joint Nature Conservation Committee, Peterborough.

Dargie, T.C.D. 1995. Sand dune vegetation survey of Great Britain: a national inventory. Part 3: Wales. Joint Nature Conservation Committee, Peterborough.

Davidson, N.C., D.A. Laffoley, D., Doody, J.P., Way, L.S., Gordon, J., Key, R., Drake, C.M., Pienkowski, M.W., Mitchell, R. & Duff, K.L. 1991. Nature conservation and estuaries in Great Britain. Nature Conservancy Council, Peterborough.

Doody, J.P. ed. 1985. Sand dunes and their management. Focus on Nature Conservation No.13, Nature Conservancy Council, Peterborough.

Gimingham, C.H. 1964. Maritime and sub-maritime communities. In: J.H. Burnett ed. The vegetation of Scotland, 67-142. Edinburgh.

Houston, J. 1997. Conservation management practice on British dune systems. British Wildlife, 8 , 297-307.

Janssen, M.P. 1995. Coastal management: restoration of natural processes in foredunes. In: M.G. Healy & J.P. Doody eds. Directions in European coastal management, 195-198. Samara Publishing Limited, Cardigan.

Mather, A.S. & Ritchie, W. 1977. The beaches of the Highlands and Islands of Scotland. Countryside Commission for Scotland, Battleby.

Pye, K. & French, P.W. 1992. Targets for coastal habitat recreation. Unpublished report to English Nature, Peterborough (F72-04-22/ES22).

Radley, G.P. 1994. Sand dune vegetation survey of Great Britain: a national inventory. Part 1: England. Joint Nature Conservation Committee, Peterborough.

Ranwell, D.S. 1972. Ecology of salt marshes and sand dunes. Chapman & Hall, London.

Ranwell, D.S. & Boar, R. 1986. Coastal dune management guide. HMSO, London.

Ritchie, W. 1993. Coastal sand dunes: natural stability and artificial stabilisation. In: A.H. Dawson, H.R. Jones, A. Small & J.A. Soulsby eds. Scottish Geographical Studies, 73-87. Universities of Dundee and St Andrews.

Ritchie, W. & Mather, A.S. 1984. The beaches of Scotland. Countryside Commission for Scotland, Perth.

Willis, A.J. 1989. Coastal sand dunes as biological systems. Proceedings of the Royal Society of Edinburgh, 96B , 17-36.

Stewart Angus, Scottish Natural Heritage Tel:01463 712221

The following LBAPs are working on Coastal sand dunes:

Originally published in: UK Biodiversity Group Tranche 2 Action Plans - Volume V: Maritime species and habitats (October 1999, Tranche 2, Vol V, p105)