Green Infrastructure

The concept of “Green Infrastructure” (GI) is gaining political momentum and has been rapidly introduced in both planning theory and policy, especially in US and Europe (see Lennon, 2014). Yet, it does not have a single widely recognised or accepted definition (Wright, 2011). The term has been adopted by various disciplines (e.g., land conservation, urban design and landscape architecture), sometimes with substantially different conceptual meanings (see EEA, 2011 for a thorough list of GI approaches). For example, the development of GI is a strategic approach to land conservation, addressing the ecological and social impacts of consumption and fragmentation of open land (Benedict and McMahon, 2006). In urban design, the concept is mainly approached as a planned network of living systems affecting the quality of life of urban population (Defra and Natural England, 2013). Although the lack of a clear and unequivocal definition can lead to confusion and misuse among academics and practitioners, and eventually to a generalization of the term to “anything green”, Wright (2011) argues that a single precise meaning of GI is problematic because the concept is still evolving and has developed in response to different needs. GI could be hence framed as a “boundary concept”, defined as “words that function as concepts in different disciplines or perspectives, refer to the same object, phenomenon, process, or quality of these, but carry (sometimes very) different meanings in those different disciplines or perspectives” (Mollinga, 2010:4). Still, there are at least two common underlying elements behind all GI approaches which can be identified (see also Mell, 2008); these are: 1) connectivity, and 2) multifunctionality. Connectivity comprises two components, structural and functional. The latter is the dynamic component expressing how landscapes allow various species to move and expand to new areas (Saura et al., 2014). Structural connectivity, equal to habitat continuity, is the static component measured by analysing landscape structure, independent of any attributes of organisms (EC, 2013b). Multifunctionality refers to multiple functions and benefits that the GI provides simultaneously on the same spatial area. For example, an area suitable for flood protection can serve for recreational needs, preservation of cultural heritage, natural pasture land for cattle and a habitat for wildlife (EC, 2012).