Conventionally, the amount of living biomass growing in a particular environment is related to the availability nutrients in the soil and the duration of the period per year which provides both sufficient moisture and temperature for vegetation to grow. Such general relationships do not apply to dryland areas at the fringe of continuous vegetation cover. The mixture of rocky surfaces and small areas with soil cover generate a complex ecohydrology. A complex interaction between runoff generating rock surfaces and small, runoff-receiving pockets of soil creates a spatially highly variable and dynamic patchwork of sites suitable for permanent vegetation. The reaction of such an ecohydrologic slope system to changing rainfall conditions is similarly complex. While the key factors of the interaction between runoff, soil and vegetation on rocky desert slopes is understood, quantitative, process-based models for the reaction of vegetation is still missing. Similarly, approaches for parameterising the spatial heterogeneity of rocky desert slopes have not yet been developed. The current project aims at both of these issues. Extensive soil mapping and a series of rainfall simulation experiments have been conducted in the Negev Desert. Based on the collected data and conceptual models for surface-vegetation interaction, quantitative models of slope eco-hydrology are developed