INTRODUCTION TO SHINGLE BEACHES & STRUCTURES

Definitions and descriptions

Shingle occurs in two basic forms and the definition includes both:

1. Shingle beaches are common and geographically widespread. They often fringe exposed coastal areas, protecting the land behind. They may be precursors to larger structures. In the most exposed locations they are devoid of vegetation, supporting ephemeral vegetation during periods when the surface remains stable;
2. Shingle structures are scarce and much less frequent in occurrence. They are restricted geographically worldwide to the more northerly and southerly latitudes where suitable-sized gravel deposits are available and in areas of high wave energy (Pye 2001). They develop when a series of beaches are piled upon each other and progressively moved out of reach of all but the most severe storms.

Management

The nature of shingle beaches restricts their use for agriculture and traditional management is limited. Shingle structures may be grazed, but on most sites vegetation is sparse. Much more significant is their importance for sea defence and the measures employed to reprofile or otherwise 'protect' them.

Reasons to restore

Shingle beaches are by their nature resilient to disturbance. They are formed and respond to changes in wave climate and storms as the material moves along the shore by long-shore drift. Vegetation, which develops on these areas is adapted to change and exposure to saltspray and comprises a number of annual species. Many beaches, especially in the south and southeast England have been 'protected' by artificial structures or reprofiled to 'improve' or help sustain their sea defence function. These actions together with shingle recycling are usually designed to retain the beaches in situ. In these situations natural rollover is prevented making opportunities for new habitat to develop through natural processes difficult.

Shingle structures are especially vulnerable to exploitation and disturbance. The destruction of the surface shingle through excavation for sand and gravel is the principle cause of loss. This has lead to major change in the biological and geomorphological interest and in many instances a reduction in their coastal defence capability. Building houses, power stations and other infrastructure developments are some of the ways in which these structures have also been destroyed.

States and values

The state of the shingle beaches and structures depends to a large degree on their stability:

• State 1 - eroding shingle tends to be associated with beaches. They exist in a highly dynamic environment and can be precursors to more stable structures. Generally they are defined by an overall deficit of material entering the system;
• State 2 - stable or accreting forms tend to be associated with shingle beaches and structures where there is a balance between erosion and accretion;
• State 3 - Over time the surface shingle is moved above the direct influence of the sea allowing relatively stable vegetation allowing a wide range of plants and animals to develop.

The resource is used for building material (sand and gravel) and some of the larger deposits have been extensively exploited. The disturbance associated with this exploitation leads to a loss of conservation interest as the surface shingle is destroyed leading to a State 4, damaged state. Although this can result in an increase in open water (gravel pits) and the development of a sometimes considerable bird interest, this is different from the original and sometimes unique vegetation and associated animals, which it replaces.

Guidance (routes to restoration)

For the purposes of this guide the route to restoration of shingle beaches is considered from two perspectives, namely:

1. Sea defence, increasing stability Erosional to Accretional (State 1 to State 2);
2. Nature conservation, increasing instability Accretional to Erosional (State 2 to State 1)

The first of these is largely concerned with maintaining the beach or structure in its current position. Thus the control or prevention of movement is seen as a key requirement when undertaking restoration activity. This can come into conflict with the nature conservation aims which see change as part of a natural and sometimes healing process in areas where human exploitation has destroyed conservation value. This second route considers the use of the forces of erosion and accretion to re-create natural shingle forms.

It is unlikely that the mature, stable, vegetated shingle surfaces will require any action other than to stop the damaging actions which have caused losses already. However in areas where the surface shingle has been excavated and remains dry (i.e. has not been infilled with open water) or where re-instatement of the shingle is required as part of remedial action following disturbance then vegetation restoration (State 4 to State 3) can be attempted.

Publications:

• Key documents: The most recent publication on shingle provides a synthesis of current knowledge of the resource from an European Union for Coastal Conservation seminar (Packham et al. 2001). Other published sources of information include (Randall 1977a for shingle shores; Randall 1977b for shingle formations; a survey of the shingle resource and its vegetation for Great Britain (Sneddon & Randall 1993a Main Report; Sneddon & Randall 1993b Wales; Sneddon & Randall 1994a Scotland; Sneddon & Randall 1994b England);
• Guides: The West Sussex Vegetated Shingle Project has produced a good practice guide for coastal defence engineers and others working on shingle beaches to minimise impact to the wildlife. A full-colour, waterproof ID card has also been produced to help on-site workers to identify the various vegetated shingle communities. Both the Good Practice Guide and the ID Cards are available on request from the projectofficer@pebbledash.org.uk.;
• Web sites: BERM - Beach Erosion in the Rives Manche, An interim report, final report and a bilingual summary of the final report are available to download at: http://www.geog.sussex.ac.uk/BERM/

Note: Coastal wetlands, saltmarshes and sand dunes have both wide-ranging and detailed reviews of management and restoration needs. The same is not true for shingle. Since preparing this section of the habitat guide and in order to rectify this, a more detailed review of the management and restoration of coastal vegetated shingle has been prepared with a contract funded by English Nature. This is included on this CD-ROM via a separate link to the 'Guide to the Management and Restoration of Coastal Vegetated Shingle'.

References

Packham, J.R., Randall, R.E., Barnes, R.S.K. & Neal, A. 2001. Ecology & Geomorphology of Coastal Shingle. Westbury Academic and Scientific Publishing, 459 pp.

Pye, K. 2001. The nature and geomorphology of coastal shingle. In: Ecology & Geomorphology of Coastal Shingle, eds.Packham, J.R., Randall, R.E., Barnes, R.S.K. & Neal, A.Westbury Academic and Scientific Publishing, 2-22.

Randall, R.E. 1977a. Shingle foreshore. In: The Coastline, ed.Barnes, R.S.K.John Wiley & Sons, Chichester, 49-61.

Randall, R.E. 1977b. Shingle formations. In: The Coastline, ed.Barnes, R.S.K.John Wiley & Sons, Chichester, 199-213.

Sneddon, P. & Randall, R.E. 1993a. Coastal Vegetated Shingle Structures of Great Britain: Main Report. Joint Nature Conservation Committee, Peterborough.

Sneddon, P. & Randall, R.E. 1993b. Coastal Vegetated Shingle Structures of Great Britain: Appendix 1, Wales. Joint Nature Conservation Committee, Peterborough.

Sneddon, P. & Randall, R.E. 1994a. Coastal Vegetated Shingle Structures of Great Britain: Appendix 2, Scotland. Joint Nature Conservation Committee, Peterborough.

Sneddon, P. & Randall, R.E. 1994b. Coastal Vegetated Shingle Structures of Great Britain: Appendix 3, England. Joint Nature Conservation Committee, Peterborough.