Ireland and Lichens
The lichen flora of Antarctica is rich in biodiversity and biomass. With this in mind it is reasonable to assume that many lichen species stayed in Ireland during its last Ice Age, particularly in areas where rock remained exposed to the air. As the Ice Age retreated (about 13,000 years ago) trees reappeared in Ireland (from areas north of the Alps) bringing a rich lichen flora with them. Sadly much of this flora is now gone due to the cutting down of our forests (habitat destruction).
Today it is estimated that there are about 1200 lichen species on the island. This rich biodiversity is due mainly to the many distinct habitats (from rocky seashores to pockets of mixed woodland to mountain areas) here and the temperate damp climate. However, the abundance of individual species is poor, with only a few specimens representing a particular species. This sparsity is due to the continued removal of our woodland, the reduction in the number of native tree species, over-maintenance of green areas (nature likes ‘wild’ places) and pollution. The high nitrogen levels on Ireland’s farmland increases the abundance of nitrogen-loving Xanthoria and Physcia species of the Xanthorion community. This reduces lichen diversity.
West of Ireland woodlands and bogs are still the best places to see the remnants of species that must have been abundant here in ancient times. There exist a few undisturbed locations where large specimens of Lobaria pulmonaria grow not just on the bole of large trees, but on the ground. The cyanobacteria lichens such as Peltigera species are still abundant in parts of ‘forgotten’ Ireland.
The Burren has a rich lichen flora, with about 350 species recorded, if the Aran Islands are included. Crustose species dominate the limestone coastal areas and the foliose species dominate the western Burren woodlands. Some are rare and this may be attributed to the unique habitat there as well as the lack of disturbance of the landscape.
The preservation of lichen rich habitats has not received the attention it deserves in Ireland. Several lichen species should be included in the Red Data book; not a single one is currently listed.