‘Hidden Polycentrism’ or ‘Subtle Dispersion’? Urban growth and long-term sub-centre dynamics in three Mediterranean cities

By analyzing long-term (1896–2011) population distribution and residential sub-centre dynamics in three urban regions of southern Europe (Barcelona, Rome and Athens), the present paper tries to discriminate ‘hidden polycentrism’ from ‘subtle dispersion’ expansion patterns and debates on the implications for planning of these settlement models. Based on morphological indicators made available on a municipal scale, descriptive statistics were used to verify if differences in the early 1900s spatial structure and long-term demographic dynamics influenced the functional organization of the three regions. Although studies investigating the expansion of Mediterranean cities highlight similarities in urban structures and functions results of the present study indicate that the three regions were characterized by a different spatial structure: while Barcelona showed a transition towards a more polycentric and balanced structure, Athens featured a rapid depopulation of the core city and a moderate expansion of the sub-centres progressively embedded in the urban area. On the contrary, Rome showed a stable distribution of population between the core city and sub-centres. The diverging spatial organization of the three regions suggests how the (supposed) homogeneity in forms and functions of the Mediterranean cities is influenced by place-specific development patterns, the spatial organization of historic settlements and the planning strategies adopted on a local scale, producing path-dependent, fragmented and sometimes peculiar urban forms.