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Coastal Sand Dunes

Sand dunes develop behind large sandy beaches which dry out at low tide allowing sand grains to be blown landward. For dunes to develop and be maintained there must be a sufficient supply of sand of the size 0.2 to 2 mm. Sand dune vegetation varies depending upon the time elapsed since sand was deposited, sand stability and localised hydrological conditions. Embryonic and mobile dunes occur mainly on the seaward side of a dune system where sand deposition is occurring; these areas are often dominated by marram grass Ammophila arenaria. Fixed dunes form where sand has stabilized and where a rudimentary soil has had a chance to develop. These areas usually have lime-rich soils and are particularly rich in plant species. On older dunes calcium may be leached from the soils leading to the development of acid dune grassland or dune heath. In wet depressions between dune ridges, dune slacks may develop. These are often characterised by the presence of creeping willow Salix repens and a number of moss species.

Sand dunes support a wide range of plant and animals, including some species which have very specialised requirements. The flora of the region’s dunes is characterised by species such as bloody crane’s-bill Geranium sanguineum, burnet rose Rosa pimpinellifolia, purple milk-vetch Astralagus danicus and lesser meadowrue Thalictrum minus. A number of rarities are also found, such as petalwort Petalophyllum ralfsii (a species listed in Annex 1 of the EU ‘Habitats Directive’ and a priority in the UK BAP), dune helleborine Epipactis leptochila var. dunensis and coralroot orchid Corallorhiza trifida.

Sand dunes are also an important habitat for species such as skylark and meadow pipit. Twite overwinter on some of the Region’s dune systems. Important breeding colonies of little tern are found on the dune/beach interface at Low Newton in Northumberland, Crimdon in County Durham, and South Gare in Redcar and Cleveland. The invertebrates found on many dune systems are of note and may include species such as dark green fritillary and grayling butterflies.

Current status

It has been estimated that England contains 11 897 ha of sand dunes. The North East contains something like 15% of the English sand dune resource.  The Region’s dunes are considered to be of great interest for the diversity of habitats that they support. By far the largest area of dunes is found in Northumberland, with smaller areas in Tees Valley and Tyne & Wear. The coast of County Durham is mostly backed by high cliffs and has a single dune system at Crimdon, near to the county boundary with Hartlepool.

Many of the Region’s dune systems have been designated as SSSIs and the dunes at Lindisfarne form part of a NNR. The best examples of these have been designated as the North Northumberland Dunes SAC under the EU ‘Habitats Directive’. The dunes at Lindisfarne also form part of a SPA, designated under the EU ‘Birds Directive’, and have been declared as a wetland of international importance under the Ramsar Convention. Parts of the Tees Bay dune systems similarly fall within the Teesmouth and Cleveland Coast SPA.

The Northumberland coastline between Amble and the Scottish border forms part of an Area of Outstanding Natural Beauty (AONB) and Heritage Coast.

Threats

  • Recreation pressures on dunes is causing erosion and a loss of plant communities on a number of sites; fires can also cause damage.
  • Overgrazing by stock can reduce the species diversity of dune grasslands and lead to eutrophication, erosion, and the spread of nettles and rank grasses. Alternatively, a lack of grazing may result in the invasion of scrub species and coarse grasses at the expense of the distinctive dune flora.
  • The non-native invasive species pirri-pirri bur Acaena novae-zelandiae is found on the dunes at Lindisfarne where it occupies a sizeable area and threatens to displace some of the native flora. It is likely to become established on other dune systems. Sea buckthorn Hippophae rhamnoides is a native shrub which forms dense stands on ungrazed dunes and can displace dune grassland communities. This is a particular problem on Seaton Dunes & Common SSSI.
  • Increases in sea-level may increase the rate of erosion at the base of sand dunes and can reduce the amount of material available for dune formation.
  • Stabilization at the back of dunes caused by agriculture, golf course management and road construction can prevent the natural landward movement of dunes. If sea levels rise this could result in dune systems being squeezed out and lost. 
  • Sand extraction removes sediment which might otherwise contribute to dune formation.
  • Loss of areas of dune to developments, such as roads and golf courses, and because of agricultural improvements, leads to habitat fragmentation and can make appropriate management more difficult to implement.
  • Falling water tables can affect the hydrology of dune slacks.

Opportunities for protection and enhancement

  • Natural England manages the dunes at Holy Island on the Northumberland coast as part of the Lindisfarne National Nature Reserve. Management is aimed at maintaining a botanically diverse grassland sward and includes the control of invasive pirri-pirri bur.
  • A number of the dune systems on the North East coast are owned and managed by conservation bodies such as the National Trust, or by local authorities.
  • The Environmental Stewardship Scheme makes payments for the management of sand dunes.
  • Control of sea buckthorn is being practised by Hartlepool Borough Council at Seaton Dunes & Common SSSI.