The potential of ‘Urban Green Commons’ in the resilience building of cities Johan Colding a, b, ⁎, Stephan Barthel a, b, c a The Beijer Institute of Ecological Economics, Royal Swedish Academy of Sciences, Stockholm, Box 50005, Sweden b Stockholm Resilience Centre, Stockholm University, Kräftriket 2B, Stockholm, Sweden c Department of History, Stockholm University, SE-10691, Stockholm, Sweden abstract article info Article history: Received 30 November 2011 Received in revised form 4 October 2012 Accepted 21 October 2012 Available online 23 December 2012 Keywords: Cultural diversity Cognitive resilience building Common property systems Ecosystem services Social–ecological memory Urban systems While cultural diversity is increasing in cities at a global level as a result of urbanization, biodiversity is decreasing with a subsequent loss of ecosystem services. It is clear that diversity plays a pivotal role in the resilience building of ecosystems; however, it is less clear what role cultural diversity plays in the resil- ience building of urban systems. In this paper we provide innovative insights on how common property sys- tems could contribute to urban resilience building. Through a review of recent findings on urban common property systems and the relevant literature, we deal with urban green commons (UGCs) and discuss their potential to manage cultural and biological diversity in cities. We describe three examples of UGCs, i.e. col- lectively managed parks, community gardens, and allotment areas, with a focus on their institutional characteristics, their role in promoting diverse learning streams, environmental stewardship, and social– ecological memory. We discuss how UGCs can facilitate cultural integration through civic participation in urban land-management, conditions for the emergence of UGCs, the importance of cognitive resilience building, and what role property-rights diversity plays in urban settings. We conclude by elucidating some key insights on how UGCs can promote urban resilience building. © 2012 Elsevier B.V. All rights reserved. 1. Introduction It is often argued that there is a positive link between cultural and biological diversity, and that reduced diversity makes the world and its inhabitants increasingly vulnerable to natural and human-induced changes (Maffi and Woodley, 2010; UNESCO, 2008). While urban scholars claim that urbanization leads to more diverse cities with higher levels of cultural diversity (Zanoni and Janssens, 2009), the movement of people to cities generally leads to a reduction in biodiversity and ecosystems (MA, 2005; Sala et al., 2000). This mismatch between cul- tural and biological diversity in cities can largely be attributed to the high concentration of humans, infrastructures and buildings in tiny geo- graphic locations. However, as argued herein, it can also be attributed to a lack of sufficient institutions for managing cultural and biological diversity. Urban areas cover less than 3% of the Earth's terrestrial surface, posing strong impacts on ecosystem services both in the local vicin- ity and at considerable distances from cities. Urban inhabitants affect distant ecosystems through trade and consumption, with cities claiming ecosystem support (including waste absorption) that sometimes is 500–1000 times larger than their own area (Folke et al., 1997). Moreover, some 78% of all carbon emissions, 60% of resi- dential water use, and 76% of wood for industrial purposes have been accredited to cities (Grimm et al., 2008). Likewise, urban devel- opment often occurs in biodiversity-rich areas (Ricketts and Imhoff, 2003), with cities tending to emerge in areas with high ecosystem productivity like landscapes suitable for agriculture and/or in coastal areas or river systems with high levels of biodiversity (Hansen et al., 2004; Ljungqvist et al., 2010). It is often proposed that dense urban settlement is less environ- mentally burdensome than urban and suburban sprawl (MA, 2005). Although this proposition needs further scientific scrutiny (Colding, 2011a), the movement of people into more densely built urban areas can lessen pressure on more remotely located ecosystems. Not included in such analyses, however, is that the urban space itself is likely to influence cognitive aspects related to environmental values of urban populations (Miller, 2005; Tidball et al., 2010). Also, urban studies reveal that biodiversity usually peaks at the level of suburbs (Blair, 2001; McKinney, 2002). Suburban parts hold more natural and semi-natural land (Sukopp et al., 1979), with a progressive increase of natural lands towards the semi-rural urban fringe (Colding et al., 2006). With this outward progression from city centers generally follows an in- crease in the proportion of per capita land ownership (Colding, 2011b), associated with a number of property rights bundles (Ostrom and Schlager, 1996). In this paper we discuss how common property rights systems and their associated bundles of entitlements hold potential for a closer ⁎ Corresponding author at: The Beijer Institute of Ecological Economics, Royal Swedish Academy of Sciences, Stockholm, Box 50005, Sweden. Tel.: +46 8 6739500; fax: +46 8 152464. E-mail address: Johanc@beijer.kva.se (J. Colding). 0921-8009/$ – see front matter © 2012 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.ecolecon.2012.10.016 Contents lists available at SciVerse ScienceDirect Ecological Economics journal homepage: www.elsevier.com/locate/ecolecon Ecological Economics 86 (2013) 156–166