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BIODIVERSITY REFERENCE
 
British habitats
 
   Maritime Sand-dunes   
 
(page 2)


 

DAMAGE, MANAGEMENT & RESTORATION


Erosion
Sand-dune development is largely about increasing stabilisation of loose sand. Sometimes this stabilisation is hindered or even reversed, often through human activity, though more natural coastline erosion is a feature of some areas, notably in East Anglia.

Destruction of vegetation, exposing the underlying sand to wind often causes a blowout. Once one is initiated, the margins of a blowout may continue to erode, resulting in extensive areas of open sand within what was previously a stabilised zone.


Path through Marram tussocks (white dune stage), Gwithian Towans, Cornwall, 2000. Here the level of trampling does not appear to be a serious concern; little open sand is exposed and the spiky nature of the marram confines humans and other animals to the narrow path. The Marram itself appears healthy.


 
Here, heavy use of a waymarked coastal footpath across the dune meadow stage has exceeded the carrying capacity of the dune turf. A small blowout has formed. The public walk through the sand, increasing erosion and destroying any natural recolonisation, or make their way around the obstruction and so widen the area of impact. Diversion of the footpath and closure of this section for repair and reinforcement appears necessary, though this assumes an alternative route is available. Photograph: Gwithian Towans, Cornwall, 2000.
 


 
Natural recolonisation of a blowout. Sand Sedge (Carex arenaria) spreads by long, straight rhizomes which can form a mesh, stabilising the sand surface and allowing colonisation by other species. Photograph: Braunton Burrows, Devon, 1967.
 


 
Wooden duckboarding is used to provide a path down the dunes and reduce further erosion, possible here as this is a climbing dune (see page 1), with the dunes formed over solid rock. Photograph: Three-Cliffs Bay, Gower Peninsula, Glamorganshire, April 2006.
 


Repair of dunes typically involves temporary fencing of affected areas, preferably with explanatory notices to reduce any public indignation at such exclusion. Marram is primarily use for replanting, often with initial protection by laying brushwood over the site. Wooden duckboarding, as shown above, can be of value in providing a path over loose sand and so reducing further erosion, but heavy pressure can break the boards and cause a safety hazard. Much more resilient, synthetic, 'wood-effect' boarding is now available.

An invasive shrub
A problem on some dunes is invasion or spread by the thorny shrub, Sea Buckthorn (Hippophaë rhamnoides). It is native on the east coast of England, extending up just into south-east Scotland, but it is also widely planted and bird-sown on British coasts. Bushes spread quickly by sucker shoots and can rapidly form impenetratable thickets, obliterating other dune habitats. However, the brushwood resulting from cutting back of this species is useful protection for marram plantings, and for blocking of unofficial footpaths into sensitive areas.


 
Sea Buckthorn (Hippophaë rhamnoides) on edge of dune system, in an area where a thicket is allowed to remain as shelter, Aberlady Bay, East Lothian, January 2002, female bush well covered in berries.
 
 
Sea Buckthorn (Hippophaë rhamnoides), close up of berries, Aberlady Bay, East Lothian, January 2002. It can be an attractive nuisance. Locally in East Lothian it is called the "Baked-bean Bush".
 


Rabbits
It is difficult to imagine what British dune systems were like before rabbits (Oryctolagus cunniculus) were introduced from southern Europe. They have an important rôle in maintaining areas of short, open turf, which in turn maintains high floristic diversity. On the other hand, their extensive warrens can weaken sand hills, causing collapse and erosion. There may also be local political problems when rabbits damage crops on adjacent farmland or extend their burrowing activities into links golf courses.
Control measures are often necessary, but total eradication may cause problems of its own. Rabbits are also important as prey for various predators.

Rabbit (Oryctolagus cunniculus) damage to sand hill, Dunnet Links, Caithness, 2001.
 
 
The burrowing is weakening the sand hill and is initiating a degree of collapse and erosion. However, rabbit activities also create niches for other plant species and there is some increase in microhabitat diversity as a result.
 


Reconstruction
A major dune reconstruction at Gullane, East Lothian, is described by Ranwell (1972). Here the dune system was used for military vehicle training during World War II. A dune ridge was constructed along the seaward boundary of the area, planted with Lyme Grass (Leymus arenarius) on the seaward side and Marram (Ammophila arenaria) on the landward side. This enclosed a large, relatively dry hollow, effectively a dune slack, which in the early 1980s was still substantially open sand. Marram was planted for stabilisation and the area has become well vegetated. A tarmac path runs down from a carpark to the popular public beach and this is lined with planted Sea Buckthorn which, due to its thorns, has helped keep the public out of the area during recolonisation.


 
Gullane, East Lothian, March 2000, showing the artificial dune ridge and the now well vegetated area formerly used for military training. The sandhills beyond are dominated by dense scrub of Sea Buckthorn (Hippophaë rhamnoides), which is also visible in the foreground where it has been planted along the sides of the path down to the beach.
 


 
Weatherproof and (maybe) vandal-proof display boards give the history of the management at Gullane, detailing continuing conservation measures.
 


 
The artificial dune ridge at Gullane, East Lothian, March 2000. Wind and human pressures are causing locally severe erosion of the ridge. The Lyme Grass has shown poor survival and Marram tussocks are becoming isolated, often with their roots exposed. Signboards, as at the top of this page, ask the public to keep off the ridge to reduce further damage.
 


References
•   Packham, J.R., & Willis, A.J. (1997) Ecology of Dunes, Saltmarsh and Shingle. Chapman & Hall, London.
•   Ranwell, D.S. (1972) Ecology of Salt Marshes and Sand Dunes. Chapman & Hall, London.
•   Richardson, D.H.S. (1981) The Biology of Mosses. Blackwell Scientific, Oxford.


Links
All links last checked on or subsequent to 01.05.2014.
External links are set to open in a new browser window.
 
•   EUCC Coastal Guide (European Union for Coastal Conservation)
    http://www.coastalguide.org/
    "The Coastal Guide is a new information service for professionals in coastal conservation, management, planning and research, especially in Europe and the Mediterranean.
Our mission: Assist professionals in finding and accessing the best available information."
A very valuable compilation with much on dune management.
 
•   UK Biodiversity Habitat Action Plans - habitats
    http://tna.europarchive.org/20110303145238/http://www.ukbap.org.uk/Habitats.aspx
    The 'official' statements on conservation statuses of British habitats, with summaries of threats and difficulties. There are links to 'Coastal sand dunes' and 'Machair' under "Priority Habitats".
 
•   The Sands of Time (Liverpool Hope Univerity College, English Nature and the Sefton Coast Partnership)
    http://www.sandsoftime.hope.ac.uk/index.htm
    Superb, illustrated account of sand-dune stages on the Lancashire coast (N.W. England).
 
•   Virtual field trip, Magilligan Sand Dunes (Geography in Action)
    http://www.geographyinaction.co.uk/Magilligan/Mag_intro.html
    Details, photographs and management notes on the Magilligan National Nature Reserve, Northern Ireland.
 
•   Coastal Dunes (Peter Slattery, Moss Landing Marine Laboratories)
    http://www.mbnms.nos.noaa.gov/sitechar/coast.html
    Descriptions of Californian dunes, primarily the Monterey Bay National Marine Sanctuary Site. Interestingly, Ammophila arenaria is an introduction and is considered a major problem, colonising dunes in a way which actually promotes erosion.
 


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© A.J. Silverside
e-mail: alan.silverside@uws.ac.uk
Page first hosted at www-biol.paisley.ac.uk/bioref/, March 2001; transferred, with minor updates, to lastdragon.org September 2009, last updated May 2014
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