Vegetation Changes on Ilkley Moor between 1964 and 1984, and Possible Environmental Causes

In recent years there has been concern about the decrease in the quality and quantity of Britain's heaths and moorlands. This concern has prompted attempts to monitor change in moorland vegetation, and programmes of action designed to halt the decline, both nationally and locally (Bunce, 1989; Hudson & Newborn, 1989a). In northern England the decline has been brought about partly by a reduction in the areal extent of the moors but mainly by changes in their species composition, with Calluna vulgaris (L.) Hull (heather) declining and grasses, Empetrum nigrum L. (crowberry) and other species increasing. These changes have been attributed to changed management practices, such as less effective burning regimes and increased sheep grazing (Bunce, 1989). However, there are few detailed quantitative studies of long-term vegetation change. This paper draws upon historical records to determine the nature and extent of change in the vegetation of Ilkley Moor over a twenty-year interval