The heathland landscape is dominated by tracts of Heather, Calluna vulgaris, and other dwarf shrubs of the Ericaceae family and is generally regarded as the response of nature to man's clearance of the primeval woodland on impoverished, base-deficient soils. There are strong ecological distinctions between heaths above 250m (moorlands), mostly on old rocks and under high rainfall, and the lowland heaths, on geologically recent clays, sands and gravels and under relatively low rainfall.