Resilienza dei sistemi urbani: reazione o risposta alla crisi?/ Resilience of urban systems: reaction or response to crisis?

As complex and adaptive socio-ecological systems, cities develop two fundamental characteristics. The first is that, like natural ecosystems, of which they are a more “artificial” outgrowth (Whiston Spirn 1984), they are endowed with resilience, that is, “the capacity of a system to absorb disturbance and reorganize while undergoing change so as to still retain essentially the same function, structure and feedbacks, and therefore identity, that is, the capacity to change in order to maintain the same identity” (Folke et al., 2010, 20). The second characteristic, consequent on the first, is that they feed on human actions. They benefit from the abilities proper to communities, organizations and institutions, and convert adaptive capacities, memories, emotions and competences into creative resources. In this respect, both the functioning of a public space, and the functioning of a landscape reserve, could be compared to the functioning of a complex socio-ecological system (SES), which is regulated through the adaptive cycle of exploitation, conservation, release and reorganization described by ecologysts as ‘panarchy’. As a matter of fact, panarchy is the key concept to explain the evolutionary core of complex adaptive systems (Gunderson & Holling, 2002). The adaptive cycle metaphor and the panarchy model, originally developed in applied research on ecological processes and then adopted in a multiplicity of fields – from economics to organizational science (Galderisi 2010), up to urban design (Wu & Wu 2013) and landscape ecology (Winston Spirn 2012) – offer an interesting tool for an interdisciplinary analysis of contemporary urban and metropolitan areas. The metaphor derives from the observation that lifetime and natural systems have to overcome four phases of the development process between discontinuities and recurring events. As the essay by Simin Davoudi highligts, there here are periods in which changes are gradual (corresponding to the exploitation phase “r”), periods characterized from increasing stagnation and rigidity (corresponding to the conservation phase “k”) and, after a release phase “Ω” in which rapid changes are triggered, periods of re-organization and renewal (corresponding to phase “α”). While the field of resources management has been experiencing for long time the phases of exploitation and conservation, the phases of release and reorganization, corresponding to the so-called “creative destruction”, as important as the first ones in the general dynamics, are, instead, almost unknown. Considering instabilities as important as stabilities in organizing behaviors, we can assume disturbance as belonging to the process, and we can assume periods of gradual change and periods of rapid transition, being complementary one each other, as coexisting, inside the life cycle (Folke, 2006).