Petrifying springs in Wales

Most bryologists are familiar with petrifying or ‘tufa’ springs as they are a habitat where bryophytes often predominate. In Britain, these springs and seepages are often associated with the pleurocarpous moss Palustriella commutata. The importance of petrifying springs in Europe is further highlighted by their inclusion within the EC Habitats Directive (92/43/EEC) as the Annex 1 habitat: H7220 Petrifying springs with tufa formation (Cratoneurion). The authors were commissioned by Natural Resources Wales (NRW) to survey a range of Welsh sites; the aim was to provide a baseline dataset for the habitat, whilst also fulfilling the EC Habitat Directive’s requirement to record the condition of this Annex 1 habitat (see Farr et al., 2014). Twenty seven sites at fifteen locations were surveyed during November 2013 and January 2014, a wet but not exceptionally cold Welsh winter. The sites ranged from natural locations such as the vertical cliff seepage faces on the Anglesey coastline (Fig. 1) to those highly influenced by historic anthropogenic activities. An example of the later was a site associated with highly calcareous, hyperalkaline (>pH 12) waters leaching from the base of spoil heaps at Herbert’s Quarry, Mynydd Du (The Black Mountain) (Fig. 2). From the outset, the project aimed to combine both botanical and hydrogeological investigations of the sites including: species-richness, water chemistry, water supply mechanisms, geological setting and identification of land use pressures.