Dune heath is an uncommon habitat in Wales. It occurs on mature, stable dunes where the initial calcium carbonate content of the sand is low. Thereafter, the surface layers rapidly become acidified after losing their calcium carbonate through leaching. The dune heath near Rhosneigr on Anglesey (shown here), is co-dominated by ericoids (Calluna vulgaris and Erica cinerea) and Cladonia lichens.