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Erosion status of sand dunes
Sand dunes are inherently unstable and cycles of erosion and stabilisation
are extremely important to the survival of their plant and animal life. However,
today there appears to have been a worldwide decrease in sediment availability
along coastlines and this is particularly marked in the case of sandy beaches
(Gribbin 1984). Evidence from Ireland suggests
that the main dune-building phase finished around 2,500 BP and that few dune
systems are actively accreting today (Carter 1985).
This is also true for the rest of the British Isles where, with notable exceptions
such as Tentsmuir
Point in Fife where local progradation is taking place. Thus it seems
the majority of other dune systems are fossilised and/or actively retreating
landwards (see Table below).
Table:
Summary of the dynamic status of English dune systems as recorded by the
sand dune survey 1987 to 1990 (Radley
1994)
| Dynamic status |
Number of sites
|
| Net marine erosion |
67
|
| Net progradation |
21
|
| Approximate equilibrium |
12
|
| Uncertain |
17
|
Comment: It is possible that many sand dune systems may be influenced
by offshore aggregate extraction (dealt with in more detail in the Guidance
included on this CD-ROM) via a separate link to the 'Guide
to the Management and Restoration of Coastal Vegetated Shingle'.
References
Carter, R.W.G.
1985.
Approaches to sand dune conservation in Ireland.
Sand Dunes and their Management, 13
Joint Nature Conservation Committee.
Gribbin, J.
1984.
The World's beaches are vanishing.
New Scientist.
Radley, G..P.
1994.
Sand Dune Vegetation Survey of Great Britain: a National Inventory, Part 1 - England.
Jiont Nature Conservation Committee.
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