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Broad habitats
High energy intertidal rock
Rocky seashores, exposed to very strong waves and currents.
High energy intertidal rock © JNCC
Strong waves and currents wash away sand and mud, leaving only bedrock or boulders on the seabed between the tides. Strong waves result when the shore faces into the prevailing wind and are also a feature of shores that are a long way from other land. Coasts in the southwest are a good example, as the waves have had the width of the Atlantic in which to develop, before crashing onto Cornwall’s shores. Rocky shores can be tide-swept, too, such as in narrow channels, where the constriction of the water produces strong currents as the tide races in and out.
On exposed shores, the occupants must contend with the full force of the waves pounding on the shoreline. Mussels, limpets and barnacles cling to the rocks, and small tufts of seaweeds are found growing in cracks and crevices. Shores where the tide races but the waves are not so strong, can support communities of seaweeds, sponges and sea squirts on the mid to lower shore.
It may seem surprising that any plants or animals can live in such an inhospitable place at all, but there is value to marine life in adapting to live here. As the conditions are too harsh for most, those that can survive have the place to themselves, and do not have to compete with many others for space or food.
Brief description of European distribution
Exposed rocky and boulder shores are found on the south-west and west coasts of Britain and Ireland, where they are exposed to the prevailing south-westerly wind. They are also found on the north-east English coast. In mainland Europe, they are associated with south and west facing headlands and coastlines, where there are rocky cliffs.
Further information sources
High energy littoral rock
(JNCC)
Interesting fact
A marine scientist can calculate the degree of exposure of a rocky shore by the plants and animals that live there.
