Agricultural intensification and the loss of heather moorland: a case study from Fair Head, Northern Ireland

摘要

The heather moorlands of Britain and Ireland are of international significance for nature conservation. Aerial photograph studies have indicated a loss of this resource and this has been attributed to agricultural intensification driven by government subsidies. As well as 1983 and 1986 aerial photographs, this paper uses vegetation surveys in 1983 and 1990 to present an assessment of vegetation change on a heather moorland in northeast Ireland. Management practices divided the case-study site into two main areas, one limed and fertilised as well as grazed by sheep (A), the other only grazed (B). The aerial photographs showed a loss of just under 40% of the Calluna dominated vegetation in area A. Ground surveys showed an increase in cover and number of graminoid species. Two hollows used for feeding sheep in 1983 were completely dominated by Holcus lanatus in 1990. In area B there was no significant difference in Calluna cover between 1983 and 1990 but the species had a more contracted distribution of cover values in 1990. However, there were significant increases in both Vaccinium myrtillus and Molinia caerulea.