Arctostaphylo-Dryasetum is a rare sub-type of Alpine and Boreal Heath which is known to occur only in Ireland on the limestone karst Burren, in County Clare. Relevés were taken across the Burren region and three groups were distinguished: Empetrum nigrum group; Erica cinerea group, Juniperus communis group. Altitude and soil conditions were found to be the main ecological factors responsible for the variation in the data set, especially pH, and the organic and mineral content. Winter grazing appears to maintain this habitat. In some areas Calluna vulgaris has encroached on the rarer plant species cutting trials are underway in an attempt to restore the habitat to good conservation status.