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Recreation on dunes
Recreational use of dunes is often seen as an important factor causing instability.
Activities come in a variety of forms and include trampling, lighting fires,
excavating sun-traps, pony riding, vehicular traffic and in the higher dune
ridges "sand sliding". The impact of these activities varies with
their scale and the intensity of use. Before physical destruction of the dune
vegetation takes place there may be subtle changes in its species composition
(Liddle & Greig-Smith 1975; Liddle
1975). Inevitably as trampling or other use intensifies then the destruction
of the surface vegetation follows, exposing the underlying sand to the action
of wind and rain. This in turn may make the dunes mobile again. Trampling damage
to dunes on beaches in Scotland, (Ritchie &
Mather 1984) affected 52% of all beach complexes. Of these 7% were severely
damaged. For example, the mature vegetation of the Opinan Dunes in western Scotland
has almost disappeared as a result of trampling and grazing pressure (Personal
observation JPD). Here, the break up of the surface vegetation led to severe
erosion in a number of places so that only limited areas of the original Salix
repens-dominated vegetation survive on a few isolated hummocks in a sparsely
vegetated sandy plain.
Where dunes are confined by man-made structures or agricultural land, the large
quantities of sand which can be released, may pose a threat to his interests.
In these instances sand mobility is seen as a 'bad thing' and there are numerous
examples of attempts to 'fix' dunes in a particular location (Ranwell
& Boar 1986). Restoration work can rehabilitate dune vegetation,
as has happened at Camber
Sands in Sussex (Boorman 1977),
though the original vegetation cannot normally be re-established in the short
term. Planting of marram grass is often used to re-create semi-stable foredunes
and given time their development to stable grey dunes will take place.
General guidance: In the situations described above, where wholesale
destruction of the vegetation occurs, remedial action must be taken. Stable
and species-rich vegetation can recover from prolonged trampling and subsequent
shifting of the dunes if the damaging activities are removed. However, severe
erosion is often very localised and whilst dune managers concern themselves
with stablisation, in the absence of grazing over adjacent areas may become
stable with an equally important loss of open dune vegetation as scrub develops
(Doody 1989).
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References
Boorman, L.A.
1977.
Sand dunes.
In: The Coastline, ed.Barnes, R.S.K.John Wiley & Sons, Chichester, 161-197.
Abstract...
Doody, J.P.
1989.
Management for nature conservation.
Royal Society of Edinburgh Proceedings. Section B (Biological Sciences), 96., 247-265.
Abstract...
Liddle, M.J. & Greig-Smith, P.
1975.
A survey of tracks and paths in a sand dune system. ii. vegetation.
Journal of Applied Ecology, 12., 909-930.
Liddle, M.J.
1975.
A selective review of the ecological effects of human trampling on natural ecosystems.
Biological Conservation, 7., 17-36.
Ranwell, D.S. & Boar, R.
1986.
Coast Dune Management Guide. Institute of Terrestrial Ecology, NERC, 105 pp.
Ritchie, W. & Mather, A.S.
1984.
The Beaches of Scotland.
Countryside Commission for Scotland.
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