ECN site code: T10
ECN monitoring by: Defence Science and Technology Laboratory
COSMOS-UK soil moisture monitoring
Min. altitude: 100 m
Max. altitude: 172 m
Area of site: 1127 ha
As well as being a Site of Special Scientific Interest (SSSI), Porton Down is also a Special Area of Conservation (SAC) and a Special Protection Area (SPA) covering over 1500 hectares. It constitutes the largest uninterrupted tract of semi-natural chalk grassland in Britain, a habitat which has declined by more than 80% in the last 50 years. As well as the grassland, the site supports large areas of mixed scrub, including juniper, and broadleaved, mixed and coniferous woodland.