SPA description
(information as published 2001)

Arun Valley

image: SPA location map 


The Arun Valley in West Sussex is located just north of the South Downs escarpment about 15 km inland from the south coast of England. It consists of low-lying grazing marsh, largely on alluvial soils, but with an area of peat derived from a relict raised bog. Variation in soils and water supply lead to a wide range of ecological conditions and hence a rich flora and fauna. Southern parts of the Arun Valley are fed by calcareous springs, while to the north, where the underlying geology is Greensand, the water is more acidic. The history of management of fields, and their water levels, determines the plant communities present, with drier fields dominated by meadow grasses, Crested Dog's-tail Cynosurus cristatus and Perennial Rye-grass Lolium perenne. In wetter areas, rushes, sedges and Tufted Hair-grass Deschampsia cespitosa are more frequent. Ungrazed fields have developed into fen, scrub or woodland. Fen areas consist of Common Reed Phragmites australis, Reed Sweet-grass Glyceria maxima and Greater Tussock-sedge Carex paniculata, often with scattered elder Sambucus sp. and sallow scrub. On firmer ground, there is Alder Alnus glutinosa, Willow Salix sp., Birch Betula sp., and sallow, with Oak Quercus robur and Hazel Corylus avellana woodland on the driest ground. The ditches and margins between grazing marsh fields have an outstanding aquatic flora and invertebrate fauna. The Arun Valley supports important numbers of wintering waterbirds, which feed in the wetter, low-lying fields and along ditches. 


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, 115 individuals representing at least 1.6% of the wintering population in Great Britain (5 year peak mean for 1992/93 to 1996/7)
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 27,241 individual waterfowl (5 year peak mean for 1992/93 to 1996/97) including: Shoveler Anas clypeata, Teal Anas crecca, Wigeon Anas penelope, Bewick's Swan Cygnus columbianus bewickii.



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.