The New Forest in Hampshire (southern England) is primarily a heathland area, parts of which have high nature conservation value. It is subject to controlled burning, an aim being to maintain the grazing quality for commoners' livestock. However, mature heathland vegetation (dominated by heather Calluna vulgaris and Erica spp.) is often richer in bird, reptile and invertebrate species (many heathland specialists of conservation interest) than younger age classes. A survey was undertaken to assess what effect a recent reduction in the area burnt annually, and horse and cattle grazing activities was having upon the structure of dominant heathland plants.
Since 1960 the area burnt annually was gradually reduced from about 1,200 ha to 320 ha.
Between March 1972 and May 1973 the heaths were surveyed and, in combination with aerial photographs, areas where gorse Ulex europaeus was dominant or co-dominant with heather, and stands of mature heather, were mapped. Each area was assigned an age category (based on counts of annual stem growth rings from sample bushes): 0-5 years, 6-10 years or 11 + years.
Browsing behaviour of ponies and cattle was recorded, supplemented by earlier observations on grazing regimes and effects of browsing.
The survey showed that despite the reduction in the area burnt annually, burning had produced an imbalance in favour of young age classes of heather and Erica, and that intensive browsing after fire was severely inhibiting gorse U.europaeus regeneration.
Large areas of the 0-5 and 6-10 year age classes of gorse were heavily suppressed by browsing, with dead stools having been severely and repeatedly bitten down by livestock.
Based on evidence from the survey, it was possible to recommend management policies aimed at correcting the imbalance in vegetation age structure whilst also satisfying the requirements of graziers.
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