Foraging pressure of the Nubian ibex Capra ibex nubiana and its effect on the indigenous vegetation of the En Gedi Nature Reserve, Israel

The population of the Nubian ibex Capra ibex nubiana in the En Gedi Nature Reserve, Israel, is divided into several herds. In a study lasting from December 1978 to May 1981, the herds moved every day along an established route, from a fixed sleeping area to the activity areas. The size of their home range was very small, about 0·5 km².

Feeding activities constituted about one half of their time. Ibex in En Gedi prefer grazing, and their impact on the perennial plants therefore depends on the amount and spread of rain — in good winters they feed mostly on annuals, and browsing pressure on perennials is minimal. It is highest during the summer months, from June to November. While browsing, the ibex are flexible in their diet, feeding on most perennial species, 40% of which are of Sudanian origin. Five species can be defined as principal food plants: Acacia raddiana, Ziziphus spina-christi, Salsola vermiculata, Pennisetum asperifolium and Moringa peregrina. Moringa, which is a ‘rare’ species, was the most sensitive to ibex browsing, and had a low rate of regeneration.