IUCN Management Category IV (Managed Nature Reserve)

Biogeographical Province 2.8.5 (British Islands)

Geographical Location 30km northeast of Swansea, within the Brecon Beacons National Park; 51°50'N, 3°36'W.

Date and History of Establishment 1975.

Area 413 ha.

Land Tenure Owned by the Nature Conservancy Council.

Altitude 308m.

Physical Features Ogof Ffynnon Ddu is a site of international geological importance and is by far the largest, and biologically the best-suited, cave system in Britain. It was discovered by the South Wales Caving Club in 1946. The system is known to contain about 22 miles of underground passages, and it is likely that other portions remain to be discovered. The difference in level between the uppermost and lowest points of the known cave system is 308 m (1010 ft), which is a record for Britain. The main streamway, which is interrupted by several large caverns, shows a wide range of interesting features such as waterfalls, cascades, potholes, sumps, ox-bows, downcut trenches, as well as impressive stalactites, stalagmites and helictites.

Climate No information

Vegetation None notable.

Fauna The aquatic cave fauna is very diverse and includes species with a restricted distribution in Britain.

Cultural Heritage No information

Local Human Population No information

Visitors and Visitor Facilities No information

Scientific Research and Facilities Main field of research are geological, hydrological and biological in the cave system. NCC staff are enagaged on survey an monitoring of wildlife including experimental exclosures to encourage development of more natural vegetation on limestone pavement and study of recolonisation following a severe fire.

A small laboratory is maintained at the nearby headquarters of the South Wales Caving Club.

Conservation Value No information

Conservation Management National Nature Reserve

Parts of the cave system can be entered only by special arrangement on a limited number of days each year.

Management Constraints The land surface is subject to an agricultural tenancy and a public footpath traverses the reserve. Occasional orienteering events are permitted. Access to the cave system is restricted to bona fide caves under a permit system. Extensive burning by accidental fire in 1976.

Staff One warden (also responsivle for three other reserves) assisted by voluntary wardens in the cave system.

Budget All expenses met by NCC.

Local Addresses

Regional Officer, Dyfed-Powys Regional Office, NCC, Plas Gogerddan, Aberystwyth, Dyfed SY23 3EB. A Cave Management Committee advises the owners on all aspects of reserve management involving other cave systems.

References

NCC hold details of published and unpublished works. A leaflet is available for visitors.

Date No information