Churchyard Lecanactis

Lichens are remarkable organisms; they are stable combinations of an alga and/ or a cyanobacteria with a fungus, living together in a symbiotic association (7). The fungus causes the alga to release sugars, which allow the fungus to grow, reproduce and generally survive. The fungus provides protection for the alga, and enables it to live in environments in which it could not survive without the fungal partner (7). A general rule is that the fungal component of a lichen is unable to live independently, but the alga may live without the fungus as a distinct species (3). Many lichens are known to be very sensitive to environmental pollution, and they have been used as 'indicators' of pollution (4). Churchyard lecanactis has an extremely slow rate of growth (6).

The churchyard lecanactis is a UK Biodiversity Action Plan Priority Species, the Species Action Plan, which is lead by the wild plant charity Plantlife, aims to maintain the existing populations and to create three new colonies by 2005 (2). In addition, Plantlife has included the churchyard lecanactis on its Back From the Brink programme (4) and has produced a leaflet 'Churchyard Lecanactis: old walls can harbour secrets', available on request from Plantlife (enquiries@plantlife.org.uk) (8). In 1990 the British Lichen Society set up the Churchyards Project, this project is concerned with research, conservation and education on lichens of churchyards (5). Regular survey work is carried out, and leaflets containing conservation guidelines have been produced (5).

Churchyard lecanactis is a rare lichen that grows in crust-like formations (2). The name of the genus Lecanactis means 'shining small bowl' and refers to the reproductive fruiting body, which contains a bag-like structure that contains the spores (7).

Inhabits external church walls that face to the north or east (2), and are sheltered from both rain and light (6). It tends to occur in coastal areas and typically grows on plaster or mortar (2).

It is known from 44 locations in south-east England (8), including sites in Somerset, Sussex, Suffolk, Kent, Dorset and Norfolk (2). Outside of the UK it only occurs in Italy (2).

Classified as Near Threatened in Great Britain and is protected under Schedule 8 of the Wildlife and Countryside Act 1981 (2).

Possible threats include the deterioration of walls on which the species occurs and repair of the walls using unsuitable materials (2). This lichen is prevented from spreading as suitable external walls are in short supply (2).