Dimensions of shrinkage: Evaluating the socio-economic consequences of population decline in two medium-sized cities in Europe, using the SULD decision support tool

All over Europe, it is a known fact that cities are shrinking. One of the main causes is population decline, but the consequent reduction of urban area is neither immediate nor easy to foresee spatially. Questions arise such as where do cities start to 'shrink' first? What are the most fragile areas that face the risk of becoming derelict? What are the most vulnerable social groups? And how does this affect real estate values across the city? Existing models for projecting the effects of shrinkage have been criticized for lacking spatial-explicitness, being excessively data-dependent, and failing to incorporate various socio-economic, urban and environmental aspects in the assessment of attractiveness of urban areas and of decisions by households. In this article, we attempt to overcome this criticism by applying the spatially-explicit Sustainable Urbanizing Landscape Development decision support tool (SULD), based on hedonic pricing theory, in two cities in southern Europe (Aveiro, Portugal and Imperia, Italy). SULD is used to project, assess and compare changes in land-use, household type distribution, real estate values and household densities, in three different scenarios of population decline (-5%, -10% and -15%). Results quantify the amount of contraction of urban area, housing quantity and living space; highlight the most problematic areas; and uncover low income households as the least affected, whereas the relocation of high income households may cause gentrification of medium income households in some areas of the historical city centre.