|IPA Factsheet - Amberley Wild Brooks and Arun Valley|
Site Description The Arun Valley floodplain consists of a complex of meadows and drainage ditches, with a diverse flora including species of brackish, calcareous and acidic waters.
Botanical Significance Noted for vascular interest. Amberley Wild Brooks is well known for its outstanding aquatic flora, but other parts are as rich. Although much grassland is semi-improved, some damp species-rich fields support nationally important populations of Carex vulpina and Oenanthe silaifolia. Potamogeton acutifolius is frequent in ditches. The Valley contains by far the greater part of the UK population of Leersia oryzoides. Other ditch margin species include Sium latifolium. The riverbanks support numerous plants of the rare Schoenoplectus x kuekenthalianus, some plants being morphologically close to the rare S. triqueter parent.
General Habitat Description Inland Surface Water (major)Grassland and Tall Forb Regularly or recently cultivated agriculture, horticulture & domestic Several area are under conservation management, including Pulborough Amberley and Waltham . Grazing appears to have been implemented in these areas. Mowing for hay and silage Cattle-grazing Arable (small part only) Wildlife conservation & research Angling (small scale) and recreation
Conservation Issues Conversion of pasture to arable. Agricultural improvement. Mismanagement of ditches: failure to clean them &/or allowing them to dry out; over-dredging them; fencing them off from livestock; influx of agricultural chemicals following conversion to arable; influx of polluted or eutrophicated water. Inappropriate grazing – usually under-grazing the problem. Mowing for silage rather than hay (late cut kills off Oenanthe silaifolia etc). Possible conflict between interests of ornithology (ground-nesting birds) and botany (some spp. like Leersia need lots of summer grazing). Inappropriate management of river banks/ damage by wash from river traffic.