“…While, on the one hand, this increase in green biomass could be an improvement when considering it as pure 'biomass' and carbon dioxide storage (Bjerke et al, 2006;McDonnell et al, 1997;Platt, 2004;Yokohari et al, 2000), this is not always the case when discussing biodiversity. Gardens and parks possess large amounts of exotic plant species and thus not only introduce non-native species, but also increase competition between exotic and native plant species, in some cases resulting in a decrease of native flora as well as native fauna ecologically linked to those native species (Alberti, 2005;Gallent et al, 2004;McKinney, 2002;Niemelä, 1999;Pauchard et al, 2006;Savard et al, 2000;Theobald, 2004;Vogtländer et al, 2004). Extensive research has been done on biodiversity in and around gardens in the Urban Domestic Gardens research in, for example, the Sheffield region, U.K. (Gaston et al, 2005a,b;Loram et al, 2007;Smith et al, 2005Smith et al, , 2006 The important role of public green in the urban ecology debate for sustainable cities can be found in studies of biodiversity in parks (Cornelis and Hermy, 2004;Hermy and Cornelis, 2000) and their role as buffers, social important locations, and landscape connectors (Angel et al, 2005;Bjerke et al, 2006;Countryside Agency Research Programme, 2002;Chiesura, 2004;Niemelä, 1999).…”