ASSESSMENT OF THE GRAZING BEHAVIOUR AND DIET SELECTION OF DARTMOOR PONIES; IN RESPECT TO THEIR USE AS A TOOL FOR THE MANAGEMENT AND CONSERVATION OF RHOS PASTURES

The Rhos pasture is an internationally important and rare habitat that needs careful management. To maintain the 'inherent ecological value' of Rhos pasture sites controlled grazing is needed. In this study the impacts of grazing by Dartmoor Ponies on biodiversity and plant species composition within a Rhos pasture site (Middle Merripit, nr. Postbridge) and a heathland regeneration site (Dendles Wood, nr. Comwood) from a previous plantation were investigated. A n indirect observational Grazing Pressure Scale (0-5) was constructed as a measure of the impact of based on trampling, soil erosion, faeces, and cropped grass. Sward height, aspect and slope were also measured. The data collected was compared using Canonical Correspondence Analysis ordinations and it was found that grazing pressure was correlated with species abundance and grazing pressure increased with diversity at the Rhos pasture site but decreased at the regenerated heath site. Diversity was high at both sites although bryophytes were rare. When compared to previous data it was found that since ponies have been introduced to Dendles Wood grasses species including Molinia have increased to a large extent, as have rushes and ferns and herb species shown a decrease. The implications o f this study for management of Rhos pastures are that ponies are successful as conservation grazers in maintaining biodiversity but suitable stocking rates need to found that control the spread of Molinia and fems and if necessary other grazing species may need to be introduced if scrub encroachment becomes problematic.Faculty of Scienc