Exploring forest ‘fringescapes’: urban growth, society and swimming pools as a sprawl landmark in coastal Rome

Abstract

The present study analyses the spatial distribution of urban settlements and residential swimming pools on the southern fringe of a large Mediterranean city (Rome, Italy) characterized by a mixed urban–rural landscape dominated by the forest of Castelporziano, one of the best preserved example of coastal flat oak wood in central Italy. Pool density was considered as a proxy for dispersed urbanization negatively impacting natural ecosystems at the local scale. We assess occurrence, frequency and dispersion of residential swimming pools as an indicator of urban sprawl around relict forest patches. A total of 6,336 swimming pools (29.4 % of total swimming pools found in Rome’s province concentrated in 19.6 % of the total surface area) were surveyed in coastal Rome (1,048 km2). The distribution of pools is spatially heterogeneous and reflects a mixed landscape structure alternating forests, cropland and human settlements with different density and compactness degree. Swimming pools concentrated in a few hotspots, especially in the western side of Castelporziano forest (Casalpalocco and Castelfusano districts) and along the coast (in Pomezia and Ardea municipalities), with a potentially higher pressure on forest ecosystem. The proposed approach based on spatial analysis proved to be effective in the study of latent landscape changes at the urban–wildland interface. Swimming pools are considered a reliable ‘sprawl’ landmark identifying dispersed settlements and indirectly quantifying the anthropogenic impact on fringe forests.