Uneven dispersion or adaptive polycentrism? Urban expansion, population dynamics and employment growth in an 'ordinary' city

Compact and mono-centric cities in southern Europe have recently experienced a chaotic expansion, in partial contrast with the spatially-balanced development typical of western European cities. Our study investigates long-term changes (1951-2011) in the spatial structure of Naples - a representative example of compact cities grown through sequential urbanization waves - discussing the weakness of its actual metropolitan organization, considered spatially-unbalanced and with a limited potential to growth. Changes over time in the spatial distribution of three variables at the municipal scale (resident population, total workers, employees in industry and services) were analyzed with the aim to identify deviations from a mono-centric growth model. Descriptive statistics and maps, non-parametric correlations and principal component analysis were used to assess spatio-temporal trends in Naples' expansion over different economic cycles with the final objective to discriminate 'residential suburbanization' from a polycentric development based on the consolidation of 'employment sub-centres'. The Naples' metropolitan region was characterized by persistent divides between urban and suburban areas, with downtown Naples concentrating a relevant share of jobs in the metropolitan region. Resident population increased more than employment in the majority of fringe municipalities, reflecting population dispersion and residential suburbanization without employment growth. These evidences suggest that policies promoting a spatially-balanced regional development were substantially ineffective in Naples. Partial failure of a polycentric development strategy is common to other socioeconomic contexts experiencing similar urbanization processes. Reconnecting regional economic dynamics with local patterns of urban growth allows an in-depth understanding of present and future trends in Mediterranean urbanization.