Modeling soil stabilization via biological restoration and rewilding (BRR) of plant functional types (PFTs) under two...

Restoring and rewilding vegetation in drylands depends heavily on limited water resources. Scenario planning can support decision-making under uncertainty, particularly for soil stabilization. Plants can be grouped into functional types (PFTs) according to their ecological requirements, allowing models to focus on functional groups rather than individual species. This study identified suitable areas for PFTs in the vulnerable dry ecosystem of Sistan, Iran, which faces severe soil erosion and uncertain water availability. PFTs were categorized based on the soil requirements of stabilizing species. Using Spatial Multi-Criteria Decision Analysis (SMCDA), we mapped suitable sites for each PFT under both hydrological degradation and recovery scenarios. The analysis incorporated key soil properties along with environmental constraints. Results show that Hamun wetland flooding expanded potential areas for hydrophyte-halophytes but reduced those for several xerophyte groups. Overlaying suitability maps with erosion sensitivity highlighted that areas requiring physical stabilization persist under both scenarios (139,993 ha in HDS and 67,356 ha in HRS), while areas suitable for biological stabilization decrease markedly under flood conditions from 99,131ha to 24,412 ha. These results indicate that biological methods alone are insufficient in erosion-sensitive areas under both scenarios. This research provides actionable insights for ecological management and biodiversity conservation, offering direct applications for restoration and rewilding in Sistan and practical applicability across degraded dryland ecosystems worldwide.