Investigating density-dependent patterns of population growth in Southern Italy, 1861–2019

Density-dependent population growth is a powerful engine of metropolitan expansion. However, spatial heterogeneity in demographic dynamics of advanced economies makes identification of density-dependent mechanisms of population growth a particularly hard task. The intrinsic linkage between long-term population increase, settlement expansion, and economic growth was investigated in Southern Italy, a peripheral European region, with use of Geographically Weighted Regressions verifying (global and local) mechanisms of density-dependent population growth in 2500 municipalities between 1861 and 2019. At the global scale, results demonstrate that population growth rates increased with population density since 1951. At the local scale, this relationship was particularly evident in the largest metropolitan regions (Naples, Bari, Palermo, Cagliari) between 1951 and 1981, becoming more intense in coastal, rural districts between 1991 and 2019. These findings delineate the predominance of density-independent mechanisms of population growth up to World War II, in a context of high fertility and accelerated emigration rates from Southern Italy. A density-dependent population growth was observed since 1951, enlarging socioeconomic disparities and consolidating the urban hierarchy centred on few large cities. Taken together, these results evidence the intrinsic nexus between demographic dynamics and agglomeration/scale factors fuelling urban expansion and state-driven industrialization in Italy.