Indirect validation of the environmental sensitive area index using soil degradation indicators: a country-scale approach

The Environmental Sensitivity Area Index (ESAI) is one of the most used frameworks to monitor land vulnerability to degradation in southern Europe, northern Africa and the Middle East. ESAI outputs were validated on the field at both local and regional scales, but a country or continental scale validation is still missing. Using non-parametric correlations and multivariate statistics, the present study contrasts the spatial distribution of the ESAI over 8100 local municipalities in Italy with 12 soil variables assessing individual soil attributes, soil degradation processes and the overall soil quality. Three supplementary variables assessing elevation, latitude and the urban–rural gradient have been also considered in the analysis. The ESAI correlated with both soil attributes (topsoil organic carbon) and degradation processes (soil contamination risk, landslide risk, grazing pressure and agricultural mechanization, considered a predisposing factor to soil compaction) varying in intensity along the elevation gradient. The approach illustrated provides an indirect evaluation of the reliability of the ESAI as a multi-domain indicator of land vulnerability to degradation in the Mediterranean region.