CONSEQUENCES OF PROTECTION FROM GRAZING ON DIVERSITY AND ABUNDANCE OFTHE COASTAL LOWLAND VEGETATION IN EASTERN SAUDI-ARABIA

Fourteen years of protection against grazing and human impacts of the coastal lowland vegetation in Eastern Saudi Arabia (an experimental si te in the vicinity of Al-Hassa region) has led to an increase of 68% i n the total cover, 33% in species richness and 32% in species relative evenness. Many of the species with significantly higher abundance in the protected area are important forage and/or fuel plants. Soil salin ity and important soil nutrients (N, K, Mg and Na) are significantly h igher in the free grazing area which may be attributable to the fact t hat the passage of herbage through the grazing animals often enhances nutrient availability.