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Providing evidence to improve practice

Individual study: Survey of moorland and hay meadows in Dartmoor ESA

Published source details

Defra (2004) Survey of moorland and hay meadows in Dartmoor ESA. Defra MA01016 report.


This study is summarised as evidence for the intervention(s) shown on the right. The icon shows which synopsis it is relevant to.

Maintain species-rich, semi-natural grassland Farmland Conservation

A randomized, replicated before-and-after trial in England (Defra 2004b) found that the conservation value of hay meadows in the Dartmoor Environmentally Sensitive Area increased during the nine years following its introduction in 1994. Eighteen randomly chosen Environmentally Sensitive Area hay meadows (with agreements aimed at habitat enhancement) were surveyed in June-July 1995 and 2003. Most hay meadows increased in conservation value, with the biggest improvement seen in poorer quality sites. There was an overall increase in plant species richness and the vegetation became closer to that of meadows characterized by crested dog’s tail Cynosurus cristatus and common knapweed Centaurea nigra (MG5 under the UK National Vegetation Classification Scheme). This was accompanied by a general trend of declining soil fertility and a narrowing of the difference in nutrient availability between sites (particularly potassium).

 

Maintain upland heath/moorland Farmland Conservation

A randomized, replicated before-and-after trial in England (Defra 2004) found that the average heather Calluna vulgaris cover on 50 moorland sites in the Dartmoor Environmentally Sensitive Area decreased from 10.3% in 1994, when the scheme was introduced, to 7.7% in 2003. This was accompanied by an increase in grazing pressure, as measured by a heather grazing index. These trends were most pronounced on acid grassland habitats, where heather cover was lowest. The tier of Environmentally Sensitive Area managements (indicating whether management is aimed at maintenance or enhancement of habitats) had little effect on these changes, and there was little evidence of any heather recovery.