Acacia salignaPlantation Impact on Soil Surface Properties and Vascular Plant Species Composition in Central Tunisia

Exotic species have been widely used in reforestation in arid areas in northern Africa, as they provide ecosystem services that native species may be unable to supply. But information on their effect on ecosystem function and composition is scarce. We have evaluated the effect of 20-year-old Acacia saligna (Labill.) H.L. Wendl. plantations on the soil surface conditions and vascular plant composition in central Tunisia. Landscape function analysis (LFA) indices of soil stability, infiltration, and nutrient recycling underneath A. saligna increased by 1%, 138%, and 148%, respectively, in comparison to bare areas. This species, however, did not affect indicators of soil surface functionality, the spatial pattern of resource sinks-sources, or vascular plant species composition at a plot scale. This was probably due to low A. saligna cover, and a limited degree of litter incorporation into the soil surface. Our results suggest that the potential for improving ecosystem function and fostering succession by usi...