Effects of Wind Erosion Control Measures on Vegetation Dynamics and Soil-Surface Materials through Field Observations and Vegetation Indices in Arid Areas, Southeastern Tunisia

Abstract

Effective land management in the Djeffara plain, southeastern Tunisia, is being constrained by increasing land degradation issues due to arid climate conditions and soil erosion. Thus, this study aims to assess the impact of the integrated control measures, namely windbreaks and controlled grazing, on the restoration of land cover dynamics in six managed rangeland areas. Land cover changes were monitored using satellite data and the derived vegetation indices (the normalized difference vegetation index (NDVI) and the soil-adjusted vegetation index (SAVI)) from Landsat 8 (OLI), both within and outside the protected areas. The findings reveal that the implemented protection measures lead to an increase in vegetation cover, diversity, and plant density. They play an important role in stabilizing the upper soil layer. The oldest protected areas, particularly those that are well-maintained with controlled seasonal grazing, experienced a reduction in sand movement. The reintroduction of grazing should, however, be controlled to prevent degradation risks. The results show strong correlations between vegetation cover and both calculated vegetation indices, (0.73 < R2 < 0.91), with more accurate estimating for the SAVI. The findings of this research can guide decision-makers for restoring degraded rangelands and planning effective control measures for wind erosion.