Buellia asterella, the Starry Breck Lichen, has been accepted for inclusion in the IUCN Global Red List with a conservation status of Critically Endangered. This is the first British lichen to be included in the list.
It is endemic to the dry grasslands of western Europe, and used to occur in small isolated populations from Italy to England and southern Norway. Now it is thought to be extinct in all but three or four locations globally, all in Germany or Norway. It was last seen in Britain at Lakenheath Warren in 1999. The causes of this decline appear to be loss of grassland habitat to agriculture and urban development, eutrophication, scrub encroachment and trampling.
Further information can be found on the IUCN website.