Size: 14.58 hectares

% of total area of SSSI's: 3.59%

Designated features: Orange Bird's foot 

General Description

On the north coast of St Martin’s, Great Bay is an east-facing beach that is protected from the prevailing winds by the main island to the south and White Island SSSI to the west. This natural protection has helped the site to accrete sand, which over millennia has developed into a dune system. The result of this natural process provides a great example of coastal succession of vegetation communities from embryo dunes through to dune scrub. At the earliest stage in the embryo dunes, species such as Sea Sandwort, Frosted Orache and Sea Rocket are common. The developing foredune is dominated by Sand Couch and Sea Holly, with the vegetation quickly changing to Marram Grass. Here uncommon species such as Sea and Portland Spurge can be found. The fixed dunes at the rear of the beach show the change from Marram grass into a rich dune grassland with species such Thrift, Red Fescue, Sand Sedge, Sea Stork’s-bill and Eyebright are present along with the occurrence of the nationally rare Orange Bird’s-foot and the rare Western Ramping Fumitory. The grassland slowly transforms back up the hill into heathland, dominated by Heather and Bell Heather, with a rich lichen flora with Cladonia sp. common. At the very top of the hill, where the vegetation reaches its climax, dense stands of Western and European Gorse dominate. To the west the area known as Frenchmen’s Graves is dominated by dense Bracken and Bramble stands.

Practical Management

Management on Plains and Great Bay is three-fold. Firstly, the area of dunes which is transitioning from Marram grass to heathland has been invaded by New Zealand Flax. This plant has the enviable title as being the world’s strongest natural fibre, so removing with a chainsaw takes a lot of time and patience which we have started over the past 2 years. The second element of management on this SSSI is to control the encroachment of European Gorse, Bracken and Bramble across the site. The Trust has broken down the European Gorse stands in the centre and east of the site over several years to create a mosaic of grass/heath and scrub. The aim in the future is to slowly break up the main stand to the west towards Tinkler’s Hill. Finally, the established and returning grassland is being grazed in partnership with local farmer, Ben Julian of Churchtown Farm, to enhance the grass and heathland diversity.