Mapping socio-environmental pressures to assess Portuguese soil vulnerability

Abstract

Soil degradation has concerning impacts on ecosystem functions and biodiversity, decreasing essential processes such as food production or sustaining water quality. We studied eight soil threats to assess degradation processes: hydrogeological risks, soil sealing, salinization, desertification, contamination, compaction, erosion and decline in soil organic matter. A knowledge-based methodology was used measure the importance of 15 anthropogenic and environmental variables, with top weights of water availability (0.11), rate of land use change (0.09) and agricultural practices (0.09). Variables were combined into one additive model per threat to assess its distribution in Portugal. Merged soil threat vulnerability maps provided a spatial representation of the distribution of aggregated soil vulnerability, to find a 58% of moderate vulnerable soils where multiple threats coexist and are key for future management changes, a 32% of low vulnerable soils with reduced levels of soil threats, where temperature and precipitation are the main drivers of soil degradation and a 10% of highly vulnerable soils, which encompasses populated urban areas and rural civil parishes, where contamination and high rates of land turnover are the main drivers. Our maps can be used to make informed decisions on soil management and establish strategic policies for a sustainable use of land.