Land quality and the city: Monitoring urban growth and land take in 76 Southern European metropolitan areas

Urban expansion determines socioeconomic and environmental changes with unpredictable impacts on peri-urban land, especially in ecologically fragile areas. The present study assesses the impact of dense and, respectively, discontinuous urban expansion on high-quality land consumption in 76 metropolitan regions of Southern Europe. Land quality indicators and land-use maps were considered together with the aim to analyze urban growth and land take processes in Portugal, Spain, Southern France, Italy and Greece. Differences in the rate of selective land take (high- vs. low-quality soils) were observed at the metropolitan scale depending on the size of urban regions, the average level of land quality and the percentage of built-up areas and cropland in the total landscape. Discontinuous residential settlements were more frequently developed on high-quality soils in respect to both dense and mixed residential settlements and service settlements. Urbanization - especially discontinuous urban expansion - consumed high-quality land mainly in Spain and Greece. The approach presented in this paper may inform joint policies for urban containment and the preservation of high-quality soils in peri-urban areas.