Low-density settlements and land use changes in a Mediterranean urban region.

摘要

This article contributes to the issue of urban sprawl in the Mediterranean region. The hypothesis illustrated here is that urban sprawl impacts directly on rural lands by triggering land cover changes (LCCs) and indirectly by fragmenting cropland and woodland patches and creating a mixed rural non farm landscape. This is mainly due to the diffusion of low-density settlements located progressively further away from the inner city. To verify this hypothesis we investigated the long-term LCCs (1960-2000) and the variation in density of buildings (1961-2001) in a large Mediterranean urban region (Rome, central Italy). The choice of our case study derives from the fact that Rome represents a paradigmatic example of semi-compact city evolving towards a dispersed urban form. A multidimensional approach was used to (i) identify the trajectories of LCCs, (ii) quantify diachronically the spatial distribution of low-density settlements, and (iii) evaluate the increase of building density within twelve basic land cover classes. We identified two axes of urban development: the former describes the urban-rural gradient determined by the traditionally compact and mono-centric spatial organization observed in the early 1960s in Rome; the latter illustrates the polycentric, dispersed urban expansion observed in the early 2000s. Taken together, our results point out the emergence of a sprawl process where low-density settlements impact on specific land uses (arable lands, olive groves, and woodlands). Finally, the article discusses the environmental implications of the polycentric model to the 'shrinking' Mediterranean cities.