1. Introduction
Shingle beaches occupy extensive stretches of the British coastline. These sites were reviewed by Fletcher et al (1984). The best examples are in north-east Scotland such as Culbin, Ferry Links, the Spey mouth and Cuthill Links. In England there are important structures on the east coast at Blakeney Point, Orfordness and on the south coast at Dungeness and Chesil Beach and at Porlock on the west coast. . They vary from sites where sand and smaller pebbles are mixed (e.g. Blakeney) through to those where there are large cobbles (e.g. Porlock, and Kingston at the mouth of the Spey). Some of the sites in north-east Scotland are relict raised beaches and are now no longer actively influenced by coastal processes as a result of isostatic uplift. Shingle often occurs as a component of dune systems and when buried under a thin veneer of sand often creates the richest lichen habitats because vascular plant growth is restricted in these situations.
The lichen flora requires stability so that species are able to colonise the pebbles and any surrounding matrix. However, in the long term succession is likely to lead to colonisation by flowering plants including scrub such as gorse. In a natural dynamic system there is usually a continuation from freshly deposited shingle through to a grass-heath, heath or scrub community.
2. Threats
2.1 Vehicle disturbance
Disturbance by vehicles is damaging to most shingle lichen vegetation and should be avoided.
2.2 Mineral extraction
Historically many shingle systems have been subject to mineral extraction and, in some cases where there are common rights, this continues usually on a small scale. Besides loss of part of the habitat to the extraction, vehicle movements are likely to be damaging.
2.3 Coastal management
As far as possible, natural processes should be allowed to operate. This is likely to give the right balance of newly deposited shingle with longer term stability at the back of the ridge. Shingle replenishment schemes where they operate should be supplied with shingle along the foreshore thereby avoiding damage to any lichen communities and also vascular plant and breeding bird interests, which will be above the high water mark and behind the main ridge.
2.4 Military activities
Shingle structures are often used for firing ranges and for other purposes. As long as there is not vehicular use away from well-established routes there is unlikely to be significant effects. Old military structures, as with buildings in old mine sites, are likely to add diversity to the site.
2.5 Trampling
Visitor pressure is likely to be less of an issue on shingle than some other coastal habitats because of the ‘unfriendly’ nature of the surface.
2.6 Scrub encroachment
Gorse (usually Ulex europaeus) can grow and cover areas of shingle to the rear of the site. Generally it should be seen as part of the natural colonisation process but there may be situations where it will need removal. Some scrub however is important for epiphytic lichens, notably the prostrate bushes of blackthorn (Prunus spinosa) at Dungeness and shrubby seablite (Suaeda vera) on the Norfolk and Dorset coasts.
3. Management
Shingle generally requires little management especially in naturally operating systems as at Blakeney Point and Orfordness. The one exception is to ensure no undue disturbance from vehicles. When Shoreline Management Plans are being prepared, the need to allow coastal processes to operate should be the preferred option on shingle shores. Where gorse threatens important lichen areas there may be a need for some careful scrub removal.
4. References
Fletcher, A., Coppins, B.J., Hawksworth, D.L., James, P.W. Lambley, P.W. (1984) Lichen habitats, Lowland Heath, Dunes and Machair, a survey by the British Lichen Society. Nature Conservancy Council, Peterborough.
Lambley, P.W. Hodgetts, N.G. (2001). Lichens and bryophytes of British coastal shingle In: Packham, J. R., Randell, R.E., Barnes, R.S.K. & Neal, A. eds. Ecology and geomorphology of coastal shingle. Otley: Westbury Publishing. pp.380-392.
Sneddon, P. Randall, R, R.E. 1993 Coastal vegetated structures of Great Britain> main report. Appendix 2 Shingle sites in Scotland (1994a). Appendix 3 Shingle sites in England (1994b). Joint Nature Conservation Committee, Peterborough.