12.8 hectares (31.6 acres) of Danebury was designated a Site of Special Scientific Interest (SSSI) in 1979. The reasons for notification are:
'Danebury Hill comprises relatively gentle slopes surrounding a chalk hill crowned by Danebury Ring, an Iron Age hill fort. The Hill fort carries a planted Beech Fagus wood, but the surrounding slopes support mixed chalk scrub, juniper Juniperus communis scrub and herb rich chalk grassland. The site is grazed by sheep and rabbits and is also maintained locally by public recreation, giving an interesting mosaic of habitats and associations. The herb rich turf is notable for the abundance of Horseshoe vetch Hippocrepis comosa and Bastard toadflax Thesium humifusum. Scarce species include Burnt tip orchid Orchis ustulata, Field fleawort Senecio integrifolius and Frog orchid Coeloglosum viride.'
This means that we have to obtain consent from English Nature to carry out any task that is likely to damage the site. There is a list of these potentially damaging operations contained within the designation. English Nature also ensure that we aim toward getting the site into a 'favourable condition' and then maintain that condition. Danebury has recently been assessed and is currently described as 'unfavourable, improving'. An assessment made in the 1990s said, 'unfavourable in decline' so we are heading in the right direction, with our current management.
Further information about SSSI
Much of the hill is covered by chalk downland, a very scarce and valuable habitat. Wildflowers growing on the hillside include pyramidal orchids, wild thyme and agrimony. Skylarks and butterflies flourish on the grassland slopes. You can see many rare Juniper bushes that are currently being assessed for condition and viability, as part of a national survey. Juniper, with its sharp black berries used to flavour gin.
Further information on the juniper survey.
A traditional breed of sheep is used to graze the site, at various locations throughout the year. Chalk downland has developed over centuries by grazing animals and the flora within it, relies on this method of management.
The Countryside Service work in partnership with a local grazier to provide a 'conservation flock' of Manx Loughton sheep. This is a traditional breed that are very similar to the sheep that would have been at Danebury in the Iron Age. Chalk down land has evolved over centuries, by the continuous presence of grazing animals and the subsequent flora relies on this type of management for its survival. Scattered scrub is also a valued habitat for nesting birds, insects and small mammals but must be controlled, so that it does not take over the grass land and revert to woods.