Nature Reserves

Ardley Quarry Nature Reserve
Managed by:	BBOWT
OS grid reference:	SP 536 273
Nearest postcode:	OX27 7NU
Usual work:	Scrub clearance

Ardley Cutting and Quarry combines limestone grassland, wetland habitat and ancient woodland with geological, paleontological and sedimentary features. This former quarry and railway cutting is therefore a natural treasure trove and Site of Special Scientific Interest (SSSI).

Geology

Ardley Quarry lies on Jurassic rocks. The exposures range from the lowest Bathonian Chipping Norton Formation of oolitic limestones, sandy limestones and mudstones, to the White Limestone Formation of micritic and peloidal limestones. The site has a diverse flora due to the mixture of shallow calcareous brown soil with outcrops of Northants sands. Areas of ill-draining clays provide wetland habitat. On a private site close to Ardley Quarry one of the longest fossilised dinosaur tracks in Britain can be found.

History

The geology at the site gives a great insight into the Jurassic history of the local area due to sedimentary features such as channels, fossil marker horizons, palaeontology and stratification. The Chipping Norton Formation exposures, with their sand-filled channels, are indicative of a period when the land was marshy. The rocks on top of this are indicative of a period of marine conditions and are mostly composed of oyster-bearing clay and rocks. There is also an abundance of gastropods, bivalves and brachiopods within the limestone.

The White Limestone (Great Oolite) floor of the quarry shows that in the middle Jurassic era, the area was near the shore of a sea. At that time, it is thought that the area was a gradually shelving mudbank. Large numbers of bivalves, gastropods, echinoids, ooliths and other benthic organisms lived in the non-tidal waters, and eventually formed the limestone at the site. Fossilised footprints on nearby sites suggest that fluctuations in sea levels occasionally exposed mudflats over which dinosaurs walked around 168 million years ago. A species of herbivorous sauropods is thought to have left 40cm long kidney-shaped impressions from its front feet and 60cm by 56cm semicircular footprints from its back feet. Some of these tracks are the first record found in the world of a change in locomotion speed and associated change in gait. In addition, three-toed footprints 80cm long, 65cm wide and up to 2m apart found close to Ardley Quarry are thought to be those of the carnivorous bipedal dinosaur Megalosaurus.

Flora and Fauna

Ardley Cutting and Quarry contains one of the largest unimproved limestone grassland habitats in the Oxfordshire Cotswolds. Within this habitat, various species of brome thrive alongside tor-grass and typical limestone grassland flora and fauna such as quaking grass, clustered bellflower, dropwort and sainfoin. Species typical of the locality including kidney vetch, horseshoe vetch, blue fleabane, bee orchid, green-winged orchid and cowslip have been recorded at Ardley Quarry. In addition, some species of flora native to the British Isles have been successfully introduced to the site. This includes dragon's teeth and broad-leaved everlasting pea.

The woodland floor is home to indicator species of ancient woodland such as lords and ladies, wood anemone and hellebore, including the uncommon green hellebore. There is a seasonal pond at the east of the site, in addition to a low-lying, marshy habitat containing willow carr, soft rush, reed canary grass and water mint.

Due to the large area of grassland habitat, the site is popular with a variety of butterfly species, including brown argus, Duke of Burgundy, dingy skipper, grizzled skipper, green hairstreak, small blue and dark green fritillary. The nationally rare four-spotted moth also breeds at the site, alongside some uncommon species of leaf beetles. The wetland areas provide ideal habitat for a range of vertebrates, such as the internationally protected great-crested newt.

Conservation Management

Scrub clearance is of key importance at Ardley Cutting and Quarry as it prevents invasive scrub from encroaching on the grassland. This activity, which OCV assists with, also helps to ensure that the species-rich unimproved limestone grassland remains relatively nutrient-poor. This is required by the flora and fauna that thrive in this habitat. It is also vital to ensure that the paleontological aspects of the site are protected.

Location

Ardley Quarry is four miles northwest of Bicester, between Ardley and Somerton. Leave the M40 at junction 10 and head onto the B430 towards Middleton Stoney. From the B430 (Station Road) turn right down Somerton Road and follow this road as it bends and meets other roads, until taking a left into Quarry Cottages Road. There is no car park at the site, but the railway cutting can be accessed via Quarry Cottages Road.