Biological and geological Site of Special Scientific Interest in Gloucestershire, United Kingdom
This article is about the Site of Special Scientific Interest in Gloucestershire. For the Local Nature Reserve in Surrey, see Rodborough Common, Surrey.
Rodborough Common is sited south of Stroud and has been owned and managed by the National Trust since 1937.[5] It is north of Minchinhampton Common. It lies on Jurassiclimestone and is on top of the Cotswold scarp. It is bounded on either side by the Nailsworth valley and the Frome valley. It is on a hill (a plateau area), and its margins are dissected by dry valleys. The sides of this plateau are steep.[1]
Rodborough Common, like Minchinhampton Common, is notified for its biological and geological importance. The grassland is unimproved, herb-rich and calcareous. There is an important geological area for fossils for research purposes.[1]
Geology
There are old quarry workings which are near Rodborough Fort. These contain exposures of Inferior Oolitelimestones of the Middle Jurassic Period. The fossils are numerous in the strata, and provide many species. Of particular interest are bivalve molluscs, and these were first defined from specimens collected on this site. The site is particularly significant as it is the only remaining one in the region. It is close to the southern edge of the Middle Inferior Oolite. This is cut out beneath the overlying Upper Trigonia Grit (across the common and to the south). In research terms this shows the effects of earth movements on the local succession.[1]
Scrub is scattered over the Common and near the edges. This include hawthorn, bramble and there are various types of small trees. Juniper is present. Where there is broad-leaved woodland, this is mainly beech and ash.[1]
Fauna
Invertebrates flourish on this site and butterflies recorded include the Duke of Burgundy and marsh fritillary. There are bugs, beetles and moths recorded. The snail Abida secale is present.[1] In 2019 a project to reintroduce the endangered Large blue to the common was undertaken with an estimated 750 butterflies emerging in the summer of 2020.[6]