Upper Arun

Also within

West Sussex County SOUTH DOWNS National Park

Condition (Natural England)

Habitats

Fast flowing river and stream

Geology & landscape

Rock Type: Greensand

Description

Area, 40 ha. 99 ac. Description The Upper Arun consists of a 13km length of the River Arun, flowing south across the weald clay and lower greensand between New Bridge, Billingshurst and Stopham Bridge, Pulborough. It supports an outstanding assemblage of breeding dragonflies including a number of rare species. The Upper Arun is relatively unpolluted and supports a diverse riverine flora. This, together with a varied river structure caused by cattle trampling and other erosion, has resulted in an extremely complex habitat upon which the dragonflies depend for breeding, feeding and resting sites. Common club rush Schoenoplectus lacustris and reed canary grass Phalaris arundinacea are abundant, together with sedges Carex spp, water plantain Alisma plantago-aquatica, branched bur reed Sparganium erectum, arrowhead Sagittaria sagittifolia and yellow water lily Nuphar lutea. The river banks are largely vegetated with grasses such as tufted hair grass Deschampsia cespitosa together with nettle Urtica dioica and docks Rumex spp. In places the banks have been trodden in by cattle and are bare of vegetation. Fifteen species of dragonfly breed within the river, including the nationally rare scarce chaser Libellula fulva, for which this is the best stretch of river in West Sussex. Also found are the notable species club tailed dragonfly Gomphus vulgatissimus, brilliant emerald Somatochlora metallica and the hairy dragonfly Brachytron pratense.

Species mentioned

Insects to look out for

These moths, butterflies and beetles are known to feed on plants recorded at this site, and carry a notable UK conservation status — but a host-plant being present doesn't mean the insect has actually been recorded here. Treat this as "worth watching for," not a confirmed sighting.

Host-plant data: Cook et al. (2025), Traits data for the butterflies and macro-moths of Great Britain and Ireland, 2024, UK Centre for Ecology & Hydrology / Butterfly Conservation; and Padovani et al. (2020), Database of Insects and their Food Plants (DBIF), UK Centre for Ecology & Hydrology (both Open Government Licence). Contains data supplied by UK Centre for Ecology & Hydrology.

Plant communities