Neath Abbey, the remains of a 12th century monastery, is one of the most important Ancient Monuments in Wales. Even as a ruin it is an imposing structure and it’s not difficult to envisage its original grandeur on the tidal banks of the Afan Clydach, overlooking the extensive marshland of the Neath Estuary against a hilly backdrop thick with woodland. Happy days! It ceased to be a monastery in the 16th century, although much of it survived for some time after that. By the second half of the 18th century, however, the Abbey was a ruin and had even been used as a copper smelting site, and later as part of a local ironworks, all in an increasingly polluted atmosphere. By the 19th century, this ancient idyll had become a ‘tip’, and remained so until heroic volunteers cleaned up the site in the 1920s and 1930s. However, air pollution continued to be noxious well into the last century and this would have had a huge effect on local wildlife, exterminating the high diversity of epiphytic lichens and bryophytes which must have been known by the Cistercian monks. But today the young sycamores and ash trees in the vicinity of the Abbey are once again plastered with lichens, mosses and liverworts, testimony to a cleaner atmosphere.
Notable lichens on the trees here include two species that are quite sensitive to air pollution, Flavoparmelia caperata and (particularly) Parmelia perlata. Both have increased greatly in abundance in our region over the last 50 years. But the trees at Neath Abbey also have a conspicuous cover of Parmeliopsis ambigua, a lichen which was once rare in southern Britain. It really likes acidic bark and some have claimed that it has increased its range as a result of acid rain – perhaps a bonus of air pollution! Other lichens abundant on the trees here include Physcia tenella and Lecidella elaeochroma.