Gorse (Ulex spp.) use by ponies in winter: Is the spatial pattern of browsing independent of the neighbouring vegetation?

Because of the progressive abandonment of agricultural practices, the extension of Atlantic dry gorse/heathlands has increased in the Cantabrian Mountains. However, there is a remarkable lack of knowledge on the spatial use of gorse by grazing animals. This study was designed to examine whether the spatial pattern of gorse browsing was independent of the neighbouring vegetation. In addition, factors that could determine the grazing/browsing pattern were investigated. For this purpose, we conducted a spatially controlled experiment using Basque Ponies (an endangered and rustic horse breed) in winter by simulating short-term grazing at a moderate stocking rate. Measurements of size and nutritive value of grass and gorse patches were made before and after grazing to analyse grazing pressure and browsing impact. Browsing damage did not occur randomly. Sward height of grass patches was the best predictor of feeding site selection, and gorse patch edges surrounding the most-used grass patches were browsed with a greater intensity. This foraging strategy appears to be the result of a trade-off between maximization of intake rate and nutritive benefits. Our results highlight the importance of spatial information for predicting gorse utilization by grazing equids, in particular the effect of utilization of gorse/grass edge. We conclude that these ponies could be a suitable tool for restoring abandoned gorse shrublands.