On the question of limits : The role of ecotones in the management and reintegration of transforming urban environments : Urban ecotones as territorial indicators and interfaces of urban reconfiguration : An applied study of the urban regional mosaic of the city of Thessaloniki, Greece

Abstract

The general topic discussed in this dissertation is the question of limits as perceived and delimited by humans. More specifically it aims to investigate the concept of ecotones as it has emerged in the theory of landscape ecology and design, that is, as a zone of transition between two adjacent ecological systems of distinct characteristics; and accordingly it aims to transfer the ecotone concept to the anthropogenic urban environment and investigate its respective implications. In this manner an urban ecotone could be defined as the transition area between at least two adjacent distinct urban fabric / biomes / biotopes of differentiated characteristics (morphological, socio-economic, typological etc), where this ecotonal space is characterized by a pronounced edge effect, in terms of intensity and diversity and a set of defined spatial {length, shape) and time {rhythm, history) characteristics restricted to the ecotonal area but ultimately linked to the adjacent patches · internal dynamics. Due to these intrinsic characteristics it can be sustained that urban ecotones, if managed properly, they can play a key role in maintaining territorial integrity (ecological, functional) and in achieving resilience and long term sustainable yields. Similarly when thought out as reprogrammable urban /territorial interfaces, a direct simile to the membrane function found in organisms and ecosystems, urban ecotones can provide the base for a paradigm shift in our contemporary perspective on cities and their functioning. A shift from a confrontational and fragmented discourse towards a synergetic and cooperational model that highlights the latent complexity present in most urban regions and adapts a proactive stance towards the problematic socio-environmental crisis most contemporary cities face today. In this sense anthropogenic transformations of the territory are understood as a direct product of the social metabolism of each territory. This approach requires apart from a traditional morphological analysis an additional phenomenological approach where the interrelation and compatibilization of anthropogenic and natural activity and dynamics can only be achieved if the necessary conceptual and design tools are developed. For this purpose a case study was selected in order to apply and test the aformentioned concepts. Thus, the selection of the urban region of Thessaloniki corresponds to a series of selection criteria linked to its special characteristics as a coastal mediterranean city with a long and continuous historic course of respective succesion phases that have given rise to heterogeneous urban forms and situations. The thesis is structured in two volumes. The first one deals with all the theoretical and bibliographical research related to the topic in question as well as corresponding analysis results and conclusions. The second volume is thought out as an analysis atlas of the case-study of the urban region of Thessaloniki, following a multi-scalar perspective: On a first level it opts for a territorial / regional analys is on the limits of the administrative region of Central Macedonia, studying the wider regional mosaic structure and respectively identifying the distinct bioregions, diverse territorial situations, landscapes and ecotones encountered within the region. On a second level, the analysis focuses on the urban region of Thessaloniki, selecting six ecotones each one corresponding to respective city limits in distinct historic periods of the city's history and serving as key spatial indicators of past and present processes and dynamics. The timely coincidence of this research work with the Revision of the Regulatory Plan ofThessaloniki renders this research as relevant and useful in providing additional insights and alternatives on the table. On a more general level, the results produced are expected to be extrapolable and applicable to other cases of urban regions, whether within the mediterranean context or not.