Alnmouth Saltmarsh and Dunes is situated in the north-east of England at Alnmouth, a village at the mouth of the River Aln where it empties into the North Sea on the east coast. The site covers the south bank of the estuary from a point due west of the village, and follows the coast south for about to Buston Links, east of High Buston. Warkworth Dunes and Saltmarsh SSSI is immediately to the south, and both fall within the scope of the Northumberland Shore SSSI. The site extends to and covers estuarine saltflats and a single ridge of dune extending south from the river mouth. Alnmouth's saltmarsh owes its origins to a shift in the course of the river which occurred in 1806. Before that time, the river passed to the west of Church Hill at the north-west end of the large single sandbank immediately to the south of the estuary, taking an oxbow course around the hill to discharge slightly south of today's river. A violent storm on Christmas Day in that year allowed the river to break through the northern extent of the sandbank to assume its current course - in the process cutting off and destroying the remains of the village's Church of St. Waleric, which stood at the northern end of the sandbank. The river's previous course became silt-filled, forming much of the saltmarsh now of scientific interest.
Vegetation
The saltmarsh is ungrazed and is dominated by sea-purslane and by the most northerly British colony of the seaweeds Bostrychia scorpioides, Fucus vesiculosus and Pelvetia canaliculata. Higher levels of the marsh support thrift, common saltmarsh-grass, sea-plantain and sea aster associated with the sea-purslane. Much of the intertidal mud has been colonised by common cord-grass, but open areas and saltmarsh creeks are used by feeding and roosting gulls, dunlin and other waders including redshank, curlew and snipe. Common reed and three locally rare species, sea rush, parsley water-dropwort and slender spike-rush are found at the freshwater inflow area of the marsh. A distinct habitat is provided by the interface between saltmarsh and dune and supports reflexed saltmarsh grass, hard-grass and sea-milkwort. The dune ridge supports marram, and lesser meadow-rue with bloody crane's-bill and hound's-tongue. Bracken is found on the lower landward slopes. The site extends to areas of shorter turf, which supports cowslip, early-purple orchid, violets, and yarrow, with widespread early forget-me-not, common cornsalad, hairy tare, and crosswort. A further distinctive habitat is provided by an area of gravel exposed by historic sand extraction, and on which grows wild thyme, common stork's-bill, mouse-ear hawkweed and common centaury together with common bird's-foot trefoil, common restharrow, blue fleabane, crested hair-grass and fern-grass. The margin of this area supports viper's-bugloss and bloody crane's-bill.
Condition
The site is divided into four units for SSSI management purposes. The condition of all was rated "favourable" in 2007 and 2009.
