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The Severn Estuary is internationally important for birds and for wildlife habitats. It may seem just like mud and saltmarsh to many, but over the whole of Europe, these estuarine environments are quite rare and very important.

The Severn Estuary is one of the most important estuaries in the UK for wintering wildfowl and waders, especially when there is severe weather affecting other sites further north and on the east coast of the UK. The Estuary regularly supports over 20,000 birds, with over 100, 000 recorded in the winter season of 1994-95. Species include European white-fronted goose, dunlin, shelduck, wigeon, teal and ringed plover.

It is part of a European network of sites known as Natura 2000 - 'your nature' which is special in a European context. These sites try to put people at the heart of nature conservation and are about 'people and nature', not 'nature without people'.

Species and Habitats of the Severn Estuary
The following habitats and species are all features for which the Severn Estuary is designated as a Site of Special Scientific Interest (SSSI). Some are also features for which the site has been designated as a Ramsar Site and SPA and also proposed for inclusion in the possible SAC. Definitive information on the features included in each designation can be found in formal designation documents, which are held by all the local authorities with jurisdiction over any part of the designated site.

Bewick’s Swan – feed on the saltmarshes and the coastal grazing marshes in the upper part of the estuary, but will also roost on the intertidal mud and sandbanks.

Sabellaria Reefs – formed by the activity of Sabellaria alveolata (or the honeycomb worm) that builds protective tubes of sand grains and which can form colonies as large reefs on hard substrates in the lower intertidal and subtidal zones.
European white fronted geese – overwinter on the Severn, roosting at night on the estuary sandbanks and feeding during the day on saltmarshes, permanent pastures and other farmland.

Saltmarsh – occurs in a zone all around the outer edges of the estuary often in a stepped formation between the low and high tide. It provides important feeding areas for waterfowl and a safe haven from the tides that flood the mudflats twice a day. Upper saltmarsh in particular makes ideal high water roost sites. European white-fronted geese, redshank and shelduck also feed on the saltmarsh itself.

Shelduck – exploit the rich resources of invertebrates found in the intertidal mudflats. They feed in groups and are found all around the estuary. Bridgwater Bay is the second largest late summer and autumn moulting area for shelduck in Europe.

Redshank & Dunlin – feed throughout the estuary, mainly on invertebrates found in the muddier finer sediments. Dunlin are found mostly on mid shore areas, whereas redshanks are often found in creeks and sub-estuaries.

Shingle and rocky shore – provide feeding
areas for many wildfowl and waders and are important roost sites at high tide. Many of the rocks are offshore and are therefore generally free from human disturbance
.Shingle and Rocky
Fish - migratory fish species including salmon, sea trout, river and sea lamprey and twaite and allis shad, migrate through the estuary from the sea to spawn in the estuaries rivers. Coastal grazing marsh – low lying wet
grasslands found at the edge of the estuary, often behind the flood defences. These habitats are important as feeding and roosting grounds for a number of important bird species, particularly grazing birds such as Bewick’s Swan and European white fronted goose. In some areas they also provide essential summer breeding grounds for wading birds such as redshank. Grazing marshes support a network of freshwater and brackish rhines and ditches.
Intertidal mudflats and sandflats – provide a refuge and a rich, plentiful source of food (invertebrates) for a wide range of migratory birds. The flatness of the landscape also allows unrestricted views to detect predators
Sandbanks – composed of a mix of mud, sand and gravel sediments that are continuously covered by water. The subtidal sandbanks in the Severn are highly impoverished as a result of estuary conditions. This makes them distinct from others in the UK due to the low number of species and individual animals found. Rhines & ditches – These provide habitats for a wide range of aquatic and brackish plant species and a diverse population of notable invertebrates.

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