SPA description
(information as published 2001)
Severn Estuary
The Severn Estuary is located between Wales and England in
south-west Britain. It is a large estuary with extensive intertidal
mud-flats and sand-flats, rocky platforms and islands. Saltmarsh
fringes the coast backed by grazing marsh with freshwater ditches
and occasional brackish ditches. The seabed is rock and gravel with
sub-tidal sandbanks. The estuary's classic funnel shape, unique in
the UK, is a factor causing the Severn to have the second- highest
tidal range in the world (after the Bay of Fundy in Canada). This
tidal regime results in plant and animal communities typical of the
extreme physical conditions of liquid mud and tide- swept sand and
rock. The species-poor invertebrate community includes high
densities of ragworms, lugworms and other invertebrates forming an
important food source for passage and wintering waders. A further
consequence of the large tidal range is an extensive intertidal
zone, one of the largest in the UK. The site is of importance
during the spring and autumn migration periods for waders moving up
the west coast of Britain, as well as in winter for large numbers
of waterbirds, especially swans, ducks and waders.
Qualifying species
For individual species accounts visit the Species
Accounts section
This site qualifies under Article 4.1 of the
Directive (79/409/EEC) by supporting populations of European
importance of the following species listed on Annex I of the
Directive:
Over winter;
Bewick's Swan Cygnus columbianus bewickii, 280
individuals representing at least 4.0% of the wintering population
in Great Britain (5 year peak mean 1991/2 - 1995/6)
This site also qualifies under Article 4.2 of
the Directive (79/409/EEC) by supporting populations of European
importance of the following migratory species:
On passage;
Ringed Plover Charadrius hiaticula, 655 individuals
representing at least 1.3% of the Europe/Northern Africa -
wintering population (5 year peak mean 1991/2 - 1995/6)
Over winter;
Curlew Numenius arquata, 3,903 individuals
representing at least 1.1% of the wintering Europe - breeding
population (5 year peak mean 1991/2 - 1995/6)
Dunlin Calidris alpina alpina, 44,624 individuals
representing at least 3.2% of the wintering Northern
Siberia/Europe/Western Africa population (5 year peak mean 1991/2 -
1995/6)
Pintail Anas acuta, 599 individuals representing at
least 1.0% of the wintering Northwestern Europe population (5 year
peak mean 1991/2 - 1995/6)
Redshank Tringa totanus, 2,330 individuals
representing at least 1.6% of the wintering Eastern Atlantic -
wintering population (5 year peak mean 1991/2 - 1995/6)
Shelduck Tadorna tadorna, 3,330 individuals
representing at least 1.1% of the wintering Northwestern Europe
population (5 year peak mean 1991/2 - 1995/6)
Assemblage qualification: A wetland of international
importance.
The area qualifies under Article 4.2 of the
Directive (79/409/EEC) by regularly supporting at least 20,000
waterfowl
Over winter, the area regularly supports 93,986 individual
waterfowl (5 year peak mean 1991/2 - 1995/6) including: Gadwall
Anas strepera, Shelduck Tadorna tadorna, Pintail
Anas acuta, Dunlin Calidris alpina alpina, Curlew
Numenius arquata, Redshank Tringa totanus,
Bewick's Swan Cygnus columbianus bewickii, Wigeon Anas
penelope, Lapwing Vanellus vanellus, Teal Anas
crecca, Mallard Anas platyrhynchos, Shoveler Anas
clypeata, Pochard Aythya ferina, Tufted Duck
Aythya fuligula, Grey Plover Pluvialis
squatarola, White-fronted Goose Anser albifrons
albifrons , Whimbrel Numenius phaeopus.
Note:
Many designated sites are on private land: the listing of
a site in these pages does not imply any right of public
access.
Note that sites selected for waterbird species on the basis of
their occurrence in the breeding, passage or winter periods also
provide legal protection for these species when they occur at other
times of the year.