AN ACCOUNT OF TUFA-FORMING(PETRIFYING) SPRING HABITATS IN THE SLIEVE BLOOM MOUNTAINS, IRELAND

摘要

Twenty-seven tufa-forming (petrifying) spring sites were found in ten valleys during a survey of the Slieve Bloom Mountains in 2007 and twenty are described. A site was defined as having 'active tufa formation inextricably associated with calcifying bryophyte species'. This involved a total area of 0.15ha but there is estimated to be twice this amount of the habitat in the study area. Several morphological types were identified which were mainly the result of a low to very low flow of water on steep to gentle slopes, but bryophyte/tufa complexes also occurred on vertical faces, in flat areas and on small waterfalls. Sources of calcium in the area are Carboniferous Limestone-derived glacial drift and limited calcareous strata within the Old Red Sandstone bedrock. The living molluscan fauna, which included the rare Vertigo geyeri, Zenobiella subrufescens and Spermodea lamellata among eight notable species, exhibited a significant diversity. Twelve bryophyte species were found and Didymodon tophaceus was the first record for Co. Offaly. Equisetum telmateia was the most characteristic vascular plant species and Geranium robertianum had a significant presence.