Once Wales probably supported a significant assemblage of lichens associated with natural outcrops of heavy metal-rich rock. Due to the destruction of these outcrops by our mining activities the survival of metallophyte lichens is now almost entirely dependant on the conservation of old metal mine sites.
Two special types of lichen are almost completely confined to these sites in Wales:-
1. Obligate metallophytes. Those lichens that appear to in some way require heavy metals and only occur on heavy metal-rich substrates.
2 Facultative metallophytes. Those lichens that tolerate heavy metals but can be found elsewhere in sites without such metals. Most of these species are probably poor competitors but can survive extreme conditions. In Wales they are mostly confined to metal-rich sites but also occur, for example, on exposed peat on the summit ridges of high mountains.
The following species fall into one or other of these categories in Wales and any threatened site supporting more than 3 of these species should be subject to a detailed assessment:
|Acarospora sinopica||Rhizocarpon furfurosum|
|Baeomyces placophyllus||Rhizocarpon oederi|
|Belonia incarnata||Sarcosagium campestre|
|Epilichen scabrosus||Steinia geophana|
|Gyalidea subscutellaris||Sterocaulon condensatum|
|Lecanora epanora||Sterocaulon dactylophyllum|
|Lecanora gisleriana||Stereocaulon delisei|
|Lecanora handelii||Stereocaulon glareosum|
|Lecanora subaurea||Stereocaulon leucophaeopsis|
|Placopsis lambii||Stereocaulon nanodes|
|Placynthiella hyporhoda||Sterocaulon pileatum|
|Polyblastia agraria||Stereocaulon symphycheilum|
|Psilolechia leprosa||Vezdaea spp.|