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

Abstract

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 using this species seems to be limited in this arid environment.

Assessing ecosystem function of restoration plantings in south-eastern Australia

“…Rehabilitated mine sites in Western Australia achieved a similar soil nutrient composition to that in remnant forest in 10-20 years (Grant et al, 2007). In contrast, in plantations of Acacia saligna in Africa, LFA scores did not differ from unplanted grassland steppe (Derbel et al, 2009). …”

Soil indicators to assess the effectiveness of restoration strategies in dryland ecosystems

“…LFA assessment represents a cheap, rapid, accurate, and repeatable methodology for the evaluation of soil functioning properties, especially in patchy drylands, and it is especially useful as a relative indicator when areas of contrasted histories and disturbance regimes of a similar ecosystem are compared. It has been used, for instance, to monitor the impacts on ecosystem functioning of restoration actions using exotic plant species (Derbel et al, 2009) or fodder shrubs (Zucca et al, 2013b), and also to monitor the effects of grazing and reforestation. LFA infiltration and nutrient cycling indexes have been observed to relate significantly to perennial species richness in Mediterranean drylands (Maestre and Cortina, 2004).…”

Multi-scale evaluation of soil functional indicators for the assessment of water and soil retention in Mediterranean semiarid landscapes

“…The LFA approach has been extensively applied in semiarid ecosystems worldwide, such as in Australia (e.g., Tongway and Hindley, 2000;McR. Holm et al, 2002;Ludwig et al, 2004;Bartley et al, 2006), Iran (Ata Rezaei et al, 2006), South Africa (Parker et al, 2009), Tunisia (Derbel et al, 2009), and Spain (Maestre and Cortina, 2004).…”