| Brighton and Lewes Downs Biosphere Reserve | |
| Photo Width: | 260 |
| Map: | UK England |
| Relief: | 1 |
| Location: | Sussex, England |
| Nearest City: | Brighton and Hove, Sussex, England |
| Coordinates: | 50.8489°N 0.1078°W |
| Area: | 29514ha |
| Established: | 2014 |
| Governing Body: | Brighton & Hove City Council, Lewes District Council, Adur District Council, South Downs National Park Authority, Natural England, Sussex Inshore Fisheries & Conservation Authority, Marine Management Organisation |
The Brighton and Lewes Downs Biosphere Reserve (established 2014) is a UNESCO Biosphere Reserve located in Sussex on the southeast coast of England near the city of Brighton and Hove. Forming a central unit of the hills of the South Downs National Park, it is centred on the Brighton chalk block that lies between the River Adur in the west and the River Ouse in the east. Chalk downland makes up the principal terrestrial landscape of the area, bounded at each end by the two river valleys. The coastline is dominated by high chalk cliffs in the east and urbanized plains in the west, running to the estuary of the River Adur at Shoreham-by-Sea.
The reserve's surface area is 29514ha. The core area is 1832ha, surrounded by buffer zone(s) of 20479ha and transition area(s) of 7203ha.
Brighton and Lewes Downs Biosphere Reserve is found within the temperate broadleaf forests biome of the Palearctic realm's British Island province and includes the following habitats: coastal chalk cliffs, sub-tidal chalk reef, freshwater wetland, shingle beaches, deciduous woodland, river estuaries and chalk grassland.
Three distinct but interrelated environments make up the biosphere reserve area; rural, coastal and marine, and urban. The rural environment contains lowland chalk grassland which is one of the richest wildlife habitats in the country and particularly important for its high botanical species diversity with up to 40-50 vascular plant species per square meter. It also supports the invertebrate communities, notably butterflies with 20 species having a substantial proportion of their breeding populations within this habitat. Characteristic species include: Phyteuma orbiculare, Wart-biter (Decticus verrucivorus), and Adonis blue butterfly (Lysandra bellargus). The coastal and marine environments are made up of a moderately exposed coast and inshore area of the English Channel with cliffs providing nesting niches for birds such as Northern fulmar (Fulmarus glacialis). The discontinuous chalk ledge to the west of Brighton gives rise to a unique series of low underwater north-facing chalk cliffs with biological records of over 300 marine species in the area.
The area is home to 211 species that have been recorded on international conservation lists, such as the European eel (Anguilla Anguilla)) in addition to 1,052 local rare species including the hedgehog (Erinaceus europaeus) and yellowhammer (Emberiza citronella). Important local genetic varieties of species include the unique elm tree