Analysis of urban ecosystem condition indicators for the large urban zones and city cores in EU : threshold assessment and exploration of the relation to ecosystem services through the application of G.I.S

anglais. As almost three out of four EU citizens live in urban areas and this number is expected to further grow, studies on urban ecosystems and their services are crucial to understand a city’s environmental structure and capabilities. The European Commission has published a relative report which suggests an urban ecosystem condition indicator framework, yet without suggesting respective thresholds that might indicate a “desired” environmental condition of the city. The European Commission’s report also points up that the relation between the ecosystem condition and the ecosystem services still needs scientific underpinning. The current study estimates 8 (eight) of the suggested by the European Commission, urban ecosystem condition indicators, for 305 EU cities, suggests relative thresholds in Urban and Metropolitan spatial scales and explores their relation to ES and the Urban Heat Island effect. Furthermore, the intermediate zone is studied to assess its contribution to the overall GI and by extension the ecosystem services provided. The estimation of the indicators was mainly based on the processing of land use spatial data of 305 EU cities with population more than 100.000 inhabitants through the application of G.I.S. The assessment of the relative thresholds is based on the method of simple averaging of each estimated indicator values for territories in EU, defined on a case-by-case basis in relation to precipitation and temperature patterns through a cluster analysis. The estimated ecosystem condition indicators and respective thresholds have been visually and numerically juxtaposed to two (2) ecosystem service indicators and the Urban Heat Island effect to examine their relation. The study found a relation between the majority of the studied ecosystem condition indicators and the examined ecosystem services and the Urban Heat Island effect either at the one or at both the examined spatial levels. The study also found a significant differentiation between the examined indicators in urban and metropolitan scale while the intermediate zone that lies in between the two spatial levels presents a considerable contribution to the overall GI and by extension the provided ES, fact that is to be considered when implementing climate adaptation strategies. Another outcome of the study is the revealing of a significant differentiation of the indicator values between the northern and the southern EU countries and the provision of evidence about the imprint that the national urban planning policies may have on the urban ecosystem condition indicators. The results of the current study are expected to work as an aiding tool of policies and planning purposes that seek to ensure urban resilience and climate adaptation.

anglais. According to the United Nations, humanity is increasingly urbanizing, and it is expected that by 2050, more than 60% of the world population will live in cities. Concerning the EU, it is estimated that almost three out of four EU citizens live in urban areas and this number will further grow. This urbanization trend raises some questions relative to the quality of life of the EU citizens who live in the largest European cities which is pretty much related to the city’s ecosystem condition and the deriving services (e.g. fresh water, recreation, climate regulation etc.). But how may this ecosystem condition be captured, what may be considered as a “good” or “bad” ecosystem condition and what is its relation to the ecosystem services provided? In an attempt to map and assess the urban ecosystems, the European Commission has specified an indicator framework that could work as a support of policies and planning purposes and involves indicators that “imprint” a city’s ecosystem condition. However, the European Commission did not suggest thresholds for these indicators and concerning the relation between the ecosystem condition and the ecosystem services it is pointed up that it still needs scientific underpinning. The current study estimates 8 (eight) of the suggested by the European Commission, urban ecosystem condition indicators for 305 EU cities in two spatial levels: urban and metropolitan. It suggests thresholds for them and explores their relation to ecosystem services. The estimated indicator values towards the EU cities are also examined for possible spatial patterns. Furthermore, the cities’ surroundings are studied to assess their contribution to the ecosystem services provided. The data that have been used to estimate the indicators are mainly land use data and the analysis is based on the application of G.I.S. The results show that the majority of the estimated indicators, are related to the examined ecosystem services either at urban or at metropolitan spatial level or at both. Furthermore, the study found that the under-study ecosystem condition indicators present significant differentiations between the urban and metropolitan spatial levels. Concerning the contribution of the cities’s surroundings to the ecosystem services provided, it was no surprise that the cities’ surroundings contribute more than the cities’ cores. However, a significant outcome of the study is the quantification of the added value that the cities’ surroundings have to the ecosystem services provided. Finally, the results show that the relative national policies may have an imprint on the cities’ ecosystem condition and that the countries of southern Europe are lagging behind concerning their urban ecosystem condition in accordance with the northern ones.