Diversification in urban functions as a measure of metropolitan complexity

Newly emerging relationships between form and function reveal the increasingly complex nature of metropolitan regions. The present study investigates spatial diversification in settlement forms and socioeconomic functions in metropolitan Attica (the administrative region including Athens, the capital of Greece), with the aim of implementing a holistic framework assessing urban complexity in contemporary cities. Taken as key components of urban complexity, morphological and functional diversity have been analysed using multi-domain indicators that describe settlement characteristics (land-use, soil sealing, building use, vertical profile of buildings, building age, construction materials) and socioeconomic functions (economic base, working classes, education levels, population age structure, composition of non-native population by citizenship, distribution of personal incomes), thus providing a comprehensive description of local-scale diversification in urban structures. A correlation analysis was used to verify the spatial coherency between individual dimensions of urban diversification. Analysis of global Moran’s spatial autocorrelation index reveals specific gradients of urban diversification that discriminate morphological attributes from socioeconomic functions. Municipalities were profiled on the basis of Pielou’s evenness indexes for each urban dimension: a factor analysis indicates latent patterns characterizing areas with high and low diversification in metropolitan functions. Urban and rural municipalities were, respectively, characterized as the most and least diversified in the study area, with peri-urban municipalities ranking in-between, evidencing a diversification gradient correlated with the distance from downtown Athens. A multidimensional analysis of the most relevant dimensions of metropolitan complexity has proved to be a promising tool for monitoring urban gradients, polycentric development and (latent) socioeconomic transformations in contemporary cities

Population Dynamics, Agglomeration Economies and Municipal Size: a Long-Term Analysis

Under the hypothesis that modifications in municipal boundaries and creation (or suppression) of new administrative units reflect a progressive adjustment toward a more balanced distribution of population over space, the present study investigates the long-term relationship (1928-2012) between urban expansion, population dynamics and municipal area in a growing metropolitan region (Athens, Greece). In expanding regions, municipal size is a key variable outlining the amount and spatial concentration of services and infrastructures, resulting to be functionally related to population density, agglomeration factors, land availability to building and characteristic socioeconomic profiles of local communities. A statistical analysis of the relationship between population density and municipal area provides basic knowledge to policy and planning adjustments toward a more balanced spatial distribution of population and land among the local government units. Descriptive statistics, mapping, correlation analysis and linear regressions were used to assess the evolution of such relationship over a sufficiently long time period. The average municipal area in Athens decreased moderately over time, with a slight increase in spatial heterogeneity. Conversely, the average population density per municipality increased more rapidly, with a considerable reduction in spatial heterogeneity. The observed goodness-of-fit of the linear relationship between population density and municipal area increased significantly over time. The empirical results of our study indicate that municipal size has progressively adjusted to population density across metropolitan areas, determining a more balanced spatial distribution of the resident population, which was consolidated by the recent administrative reform of the local authorities in Greece (the so called ‘Kallikratis’ law). Such conditions represent a base for the informed analysis of the spatial structure of local administrative units and they contribute to the debate on the optimal size of municipalities and other administrative districts with relevant impact on both urban and metropolitan scales of governance

Il monitoraggio del consumo del suolo in Italia

La progressiva artificializzazione e cementificazione del territorio, legate sempre più spesso a un’espansione urbana incontrollata e non pianificata, sono responsabili del consumo del suolo, particolarmente degradato quando viene coperto in maniera permanente con materiali impermeabili come l’asfalto, con risvolti sia sul piano ambientale che su quello economico. Nel presente studio viene illustrata la metodologia di analisi del consumo di suolo sviluppata dall’ISPRA, che ricostruisce l’andamento del fenomeno in Italia dal 1950 ai giorni nostri, integrando dati campionari che derivano da un monitoraggio dettagliato di tipo puntuale con dati di osservazione della terra a livello europeo. Per i sei anni di rilevazione della serie storica disponibile (1956, 1989, 1996, 1998, 2006, 2010), sono stati prodotti indicatori per rilevanti ambiti amministrativi, che hanno evidenziato un consumo di suolo crescente nel tempo, dalla scala comunale a quella nazionale, passando dal 2,8% di superficie consumata totale nel 1956 al 6,9% nel 2010. In base ai risultati, l’aumento del consumo di suolo, che avviene soprattutto a discapito dei paesaggi peri-urbani, non è imputabile solo alla crescita demografica. Appare dunque necessaria una regolamentazione più stringente della crescita urbana che possa stimolare la rigenerazione dei centri esistenti, forme di insediamento più compatte, e la protezione delle aree naturali e agricole.The progressive land exploitation, increasingly related to exurban development and urban sprawl, produces the consumption of soil, particularly degraded when it is permanently covered with impervious materials as the asphalt, with environmental as well as economic implications. The present study illustrates a procedure developed by the Italian National Institute for Environmental Research and Protection, for assessing soil consumption in Italy. This procedure reconstructs the evolution of the phenomenon from 1956 to the present day, integrating data derived from a detailed monitoring of sample plots with earth observation data at European level. The indicators, produced for relevant administrative areas at six points in the investigated time (1956, 1989, 1996, 1998, 2006, 2010), showed an increasing sealed area over the years, both on local and national scale. Interestingly, on the basis of our results, soil consumption rose from 2.8% in 1956 to 6.9% in 2010 in Italy and this increase, occurring mainly at the expense of peri-urban landscapes, is not only due to population growth. Therefore, a more efficient regulation of the urban development is needed to stimulate the regeneration of city centres, more compact forms of settlement, and the protection of natural and agricultural areas

Revisiting "Southern" Sprawl : Urban Growth, Socio-Spatial Structure and the Influence of Local Economic Contexts

Given its unpredictable nature, urban sprawl in the Mediterranean region is considered an intriguing (and intricate) socioeconomic issue.Since the 1970s, urban dispersion advanced rapidly in southern Europe-irrespective of a city's size and morphology-withurbanization rates growing faster than population. A comparison between the metropolitan areas of Barcelona, Rome and Athens reveals how sprawl has occurred in different ways in the three cities, highlighting peculiar relationships between urbanization, land-use and economic structures. Sharing common drivers of change related to population dynamics, socio-spatial structure and deregulated urban expansion, sprawl has adapted to the local economic, cultural and environmental context. Barcelona shows a dispersion pattern towards a more spatially-balanced morphology, with expanding sub-centres distributed around the central city, Rome appears to be mostly scattered around the historical city with fragmentedGiven its unpredictable nature, urban sprawl in the Mediterranean region is considered an intriguing (and intricate) socioeconomic issue. Since the 1970s, urban dispersion advanced rapidly in southern Europe-irrespective of a city's size and morphology-with urbanization rates growing faster than population. A comparison between the metropolitan areas of Barcelona, Rome and Athens reveals how sprawl has occurred in different ways in the three cities, highlighting peculiar relationships between urbanization, land-use and economic structures. Sharing common drivers of change related to population dynamics, socio-spatial structure and deregulated urban expansion, sprawl has adapted to the local economic, cultural and environmental context. Barcelona shows a dispersion pattern towards a more spatially-balanced morphology, with expanding sub-centres distributed around the central city, Rome appears to be mostly scattered around the historical city with fragmente

Complexity in action: Untangling latent relationships between land quality, economic structures and socio-spatial patterns in Italy

Land quality, a key economic capital supporting local development, is affected by biophysical and anthropogenic factors. Taken as a relevant attribute of economic systems, land quality has shaped the territorial organization of any given region influencing localization of agriculture, industry and settlements. In regions with long-established human-landscape interactions, such as the Mediterranean basin, land quality has determined social disparities and polarization in the use of land, reflecting the action of geographical gradients based on elevation and population density. The present study investigates latent relationships within a large set of indicators profiling local communities and land quality on a fine-grained resolution scale in Italy with the aim to assess the potential impact of land quality on the regional socioeconomic structure. The importance of land quality gradients in the socioeconomic configuration of urban and rural regions was verified analyzing the distribution of 149 socioeconomic and environmental indicators organized in 5 themes and 17 research dimensions. Agriculture, income, education and labour market variables discriminate areas with high land quality from areas with low land quality. While differential land quality in peri-urban areas may reflect conflicts between competing actors, moderate (or low) quality of land in rural districts is associated with depopulation, land abandonment, subsidence agriculture, unemployment and low educational levels. We conclude that the socioeconomic profile of local communities has been influenced by land quality in a different way along urban-rural gradients. Policies integrating environmental and socioeconomic measures are required to consider land quality as a pivotal target for sustainable development. Regional planning will benefit from an in-depth understanding of place-specific relationships between local communities and the environment

A New Approach to Land-Use Structure. Patch Perimeter Metrics as a Spatial Analysis Tool

This work introduces a new class of landscape metrics characterizing basic features of patch perimeters. Specific computation on patch perimeters was carried out on fine-grained land-use maps with the aim to characterize spatial patterns of neighbor patches, evidencing contact points and perimeter length between two (or more) land-use types. A detailed set of class and landscape metrics were derived from such analysis. This approach is complementary to classical landscape metrics and proved to be particularly useful to characterize complex, fragmented landscapes profiling metropolitan regions based on integrated evaluations of their structural (landscape) and functional (land-use) organization. A multivariate analysis was run to characterize distinctive spatial patterns of the selected metrics in four metropolitan regions of southern Europe reflecting different morphological configurations (Barcelona: compact, polycentric; Lisbon: dispersed, mono-centric; Rome: dispersed, polycentric; and Athens: compact, mono-centric). Perimeter metrics assumed different values for each investigated land-use type, with peculiar characteristics associated to each city. Land-use types assessing residential, discontinuous urban patches were associated to particularly high values of perimeter metrics, possibly indicating patch fragmentation, spatially-associated distribution of land-use types and landscape complexity. Multivariate analysis indicates substantial differences among cities, reflecting the range of morphological configurations described above (from compact mono-centric to dispersed polycentric) and suggesting that urban expansion is accompanied with multiple modifications in the use of the surrounding non-urban land. The computational approach proposed in this study and based on spatially-explicit metrics of landscape configuration and proximity may reflect latent changes in local socio-spatial structures. Our results demonstrate that scattered urban expansion determines a polarization in suburban areas with highly fragmented and more homogeneous landscapes, respectively, associated with mixed cropland and forest systems

Land quality, sustainable development and environmental degradation in agricultural districts: A computational approach based on entropy indexes

Land Degradation (LD) in socio-environmental systems negatively impacts sustainable development paths. This study proposes a framework to LD evaluation based on indicators of diversification in the spatial distribution of sensitive land. We hypothesize that conditions for spatial heterogeneity in a composite index of land sensitivity are more frequently associated to areas prone to LD than spatial homogeneity. Spatial heterogeneity is supposed to be associated with degraded areas that may act as hotspots for future degradation processes. A diachronic analysis (1960-2010) was carried out at the agricultural district scale in Italy to identify environmental factors associated to spatial heterogeneity in the level of land sensitivity to degradation based on the Environmentally Sensitive Area Index (ESAI). In 1960, diversification in the level of land sensitivity measured through two common indexes of entropy (Shannon's diversity and Pielou's evenness) increased significantly with the ESAI, indicating a high level of land sensitivity to degradation. In 2010, surface area classified as 'critical' to LD was the highest in districts with evident diversification in the spatial distribution of ESAI values, confirming the hypothesis formulated above. Entropy indexes, based on observed alignment with the concept of LD, constitute a valuable base to inform mitigation strategies against desertification

Demographic transitions and socioeconomic development in Italy, 1862-2009 : a brief overview

The present study investigates long-term population dynamics in Italy, 1862-2009, in light of Demographic Transitions (DTs). Under the assumption that DTs are multidimensional processes of change involving several aspects, including population structure and dynamics, an exploratory analysis was carried out in this study to verify temporal coherency of 15 indicators in Italy, identifying homogeneous time periods with distinct demographic characteristics. Indicators' trends were identified using a multivariate statistical approach. The results of this study allow empirical testing of the assumption of temporal coherence between different aspects of a long-term DT, distinguishing distinctive population dynamics and the differential impact on population structure over two centuries. After a relatively long period of demographic stability, the time window encompassing the two World Wars-approximately between 1921 and 1951-was identified as a primary turning point of population dynamics in Italy; a second turning point was estimated at the beginning of the 1970s. These time intervals may represent conditions of dynamic equilibrium between demographic and socioeconomic contexts, highlighting latent system transitions. The study concludes by outlining the importance of a more effective integration of demographic transition theories into a broader sustainability framework, and implementing a diachronic analysis of political, economic, and social forces associated with population dynamics in both advanced economies and emerging countries

Fallow land, recession and socio-demographic local contexts : recent dynamics in a mediterranean urban fringe

Urban settlements have globally expanded into rural land. Being influenced by complex socio-environmental dynamics and sometimes acting as a reserve of economic value, fallow land has characterized rural areas in a distinctive way over the last decades. The present work debates on the role of fallow land as a component of Mediterranean peri-urban landscapes, considering together different aspects from environmental/agronomic and regional science perspectives. An empirical analysis of the latent relationship between spatial distribution of fallow land, agricultural landscape (land-use, territorial, and topographic characteristics), and urban sprawl was carried out in a representative Mediterranean case study (Athens, Greece) evidencing the possible linkage between urban growth/containment, conservation of rural biodiversity/local traditions, and fallow land (intended as a candidate source of buildable land) in fringe districts. Urban growth at the local scale was contrasted with the spatial distribution of fallow land under sequential expansions and recessions of the regional economic system. Conservation of marginal rural land in fringe districts-including fallow land-is a necessary target of any sustainable land management strategy in metropolitan contexts experiencing rapid socioeconomic transformation

In-between sprawl and neo-rurality : Sparse settlements and the evolution of socio-demographic local context in a Mediterranean region

Dispersed urbanization during the last half century has transformed metropolitan regions into well-connected, low-density residential areas. However, this kind of urbanization has changed irreversibly the traditional rural landscape around cities, leading to a new definition of 'rurality'. The present work discusses the intimate relationship between urban sprawl and new forms of rurality. Considering economic downturns and the possible impact on landscape transformations, our study focuses on a representative Mediterranean case of urban sprawl (the metropolitan region of Athens, Greece). In this area, urban settlements expanded rapidly into fringe land, producing relevant socio-demographic transformations that have determined uneven changes in rural landscapes. A spatially-explicit investigation of local-scale dynamics that characterize population residing in sparse settlements over a long time period (1961-2011)-encompassing distinct phases of urban growth and rural development-is relevant for analysis of local changes in the relationship between sprawl and new forms of rurality. A new concept of 'rurality'-adapting to rapidly-evolving, mixed rural/peri-urban contexts-require reframing the relationship between rural landscapes, scattered settlements, economic cycles and socio-demographic aspects, in the light of a truly sustainable development of local territories