A multi-domain framework for mapping soil degradation susceptibility in Mediterranean landscapes

Preventing soil degradation requires identifying areas where high intrinsic susceptibility converges with anthropogenic influences. Achieving this purpose relies on accurate, up-to-date soil information and integrated multi-domain assessment. Building on the ongoing WRB soil map update in mainland Portugal at 1:100,000, where delineated land units were created based on soil-forming factors. This study proposes a multi-domain framework for assessing soil degradation susceptibility. Applied to two representative regions of southern Portugal (Coruche and Beja), it integrates four domains—physical, chemical, erosion risk, and water deficit—using a non-compensatory approach. Each domain is assigned a susceptibility level (1-4) based on the maximum indicator value. Intrinsic susceptibility analysed at land-unit level is combined with anthropic pressure derived from the national Land Use/Cover Map (2023) to identify priority areas for soil monitoring and conservation purposes. Although moderate susceptibility dominates in both regions, distinct patterns emerge. In Coruche, chemical limitations associated with coarse-textured soils and low organic carbon content are dominant, whereas in Beja, physical limitations linked to fine-textured, shallow soils prevail. Multi-domain convergence and hotspots are higher in Beja, especially in steeper landscapes composed of schists, intermediate-mafic metamorphic rocks, and non-consolidated limestones, where intrinsic vulnerability coincides with intensive agricultural use. The framework provides a spatially explicit, process-based approach to integrate multiple soil threats within a harmonised mapping context. It supports reproducible and policy-relevant soil monitoring aligned with Land Degradation Neutrality objectives and emerging European soil legislation as well as being applicable to other Mediterranean regions.