Salt Marsh - More information

Sea purslane
Sea Purslane - Barry Yates

Between the flood bank and the tidal river, a salt marsh has developed which is covered by most tides. The level of the mud is slowly, but constantly rising. At slack water either side of high tide, the suspended silt particles, which have been brought down by the river, sink and are deposited around the roots and stems of salt marsh plants. These are specially adapted to living in a soil with a very high salt concentration and are called halophytes.

The bare mud is first colonised by the fleshy (succulent) green glasswort (Salicornia sp.) but as the level of the mud rises and is covered by water for a shorter time, other plants become established. These include sea purslane (Halimione portulacoides) which has flattened grey-green leaves, sea spurrey (Spergularia media), which may be distinguished from the similar sea blite (Suaeda maritima) when not in flower, by the whitish scale at the base of the leaves, and the red fescue grass (Festuca rubra). Still higher and reached only by the highest tides are the grey-green sea wormwood (Artemesia maritima) and the mauve-flowered sea aster (Aster tripolium). The seed and fruit of these plants are mainly dispersed in sea-water by the movement of the tides.

Sea aster BY
Sea Aster - Barry Yates

It is probable that the earthen bank that runs on the eastern side of the river at the lower end of the valley was built during the medieval period to prevent flooding and the land to the foot of the hill was "inned" or reclaimed and converted from marsh to meadow. It is shown on a map of 1618 and in 1722 Edward Stanford - yeoman - was required "to keep in repair the wall of 49 acres of the salt marsh which had been inn'd from the sea". Skylarks and meadows pipits nest in the fields behind the flood bank, but whereas the skylark sings as it rises into the sky, the meadow pipit sings as it descends in a parachute-like flight. Redshank nest among the tussocky grass and feed in nearby shallow water.

You can find out more about salt marsh from the Beaches at Risk website

Seven Sisters Country Park