Soil Matters? A Multivariate Analysis of Socioeconomic Constraints to Urban Expansion in Mediterranean Europe

Urban expansion and socioeconomic transformations of metropolitan regions may negatively impact environmental quality and functions of peri-urban landscapes. In the present study, the role of continuous and discontinuous urban expansion as a driver of high-quality soil consumption has been investigated in 66 southern European metropolitan regions. Landscape metrics and socioeconomic indicators were considered together in a multivariate exploratory analysis with the aim to assess the intensity of recent urban expansion (2000−2010) and the consequent depletion of different soil types in Portuguese, Spanish, French, Italian and Greek cities. Overall, urban expansion involved preferentially high-quality soils in the study area. A Principal Component Analysis identified diverging city profiles as far as spatial patterns of soil consumption are concerned. Per-capita declared income, income growth rate, population density and landscape diversity were highest in metropolitan regions where urban expansion consumed soils with lower quality than non-urban soils. Urban expansion consumed high-quality soils in metropolitan regions with low per-capita built-up area, low soil quality index and peri-urban landscapes dominated by forests. Results of our study inform policies for urban containment. Design of effective measures mitigating loss of high-quality peri-urban soils requires a comprehensive understanding of multiple impacts of local socioeconomic contexts on land consumption processes.