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State 4 Disturbed or Excavated shingle
Many of the larger shingle structures have suffered from major losses of the
surface shingle. In this state, as the surface is excavated the structure of
the shingle (ridges and lows), vegetation and associated animals is lost. There
are two principle effects which depend on the level to which the excavation
(or disturbance) takes place:
- At or above the water table
In a few cases the excavation does not reach the water table. Though the original
surface shingle is lost, shingle remains the dominant substrate. At a few sites
recolonisation may have taken place. This can occur both within the body of
the shingle structure as well as at the edges of sites and may increase the
overall biodiversity (see discussion Chapter 9.4.1 Doody
2001).
- Below the water table
 In
many cases the shingle is excavated to below the water table and open water
'gravel pits' develop. These support their own flora and fauna and restoration
of the gravel surface is not normally possible.
Caption:
Newly excavated gravel pits at Dungeness, Kent. A large part of these areas
have subsequently become part of an extensive RSPB wetland nature reserve. Note
picture was taken before the RSPB stopped selling gravel winning concessions
at the site.
Comment: Although generally excavated shingle areas have a reduced
value for nature conservation, there are replacement
values associated with the open water gravel pits.
References
Doody, J.P.
2001.
Coastal Conservation and Management: an Ecological Perspective. Kluwer, Academic Publishers, Boston, USA, 306 pp.
Conservation Biology Series, 13
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