Evidence-based mangrove restoration and site selection in arid and hypersaline coastal environments of Saudi Arabia

Abstract

Mangroves in Saudi Arabia, dominated by Avicennia marina and localized stands of Rhizophora mucronata, are vital for coastal protection, biodiversity support, and carbon sequestration. Despite their ecological importance, these ecosystems face increasing pressures from urban expansion, industrial discharges, aquaculture, oil spills, and marine litter, compounded by arid climatic conditions, hypersalinity, and limited freshwater inflow. This study synthesizes current knowledge on mangrove distribution, habitat quality, edaphic factors, tidal influence, and anthropogenic stressors along the Red Sea and Arabian Gulf coasts to develop an evidence-based framework for site selection in restoration (re-establish mangroves and afforestation (planting in new suitable coastal areas) initiatives. PRISMA 2020 guidelines were followed for the systematic literature review. A six-parameter Site Selection Framework, encompassing soil depth, elevation, tidal and wave energy, soil texture, water salinity, and temperature, was established, with parameters weighted according to their ecological importance. A Composite Site Viability Index (SVI) integrates these parameters, enabling the objective ranking and prioritization of sites. Application of the framework identifies critical habitat constraints, species-specific tolerances, and restoration opportunities, aligning with the Saudi Green Initiative and Vision 2030 goals to plant over 50 million mangrove trees. By combining biophysical assessment, GIS-based pre-screening, and field verification, this approach can provide a replicable method for guiding mangrove restoration planning, reducing failure rates, and enhancing ecosystem resilience in arid and hypersaline environments.