Article Preview
TopIntroduction
Urban areas have become increasingly important for ecosystem services (ESS) and biodiversity management as more than 50% of the world’s population now lives in cities; a share that is estimated to reach 70% by 2050 (UN DESA, 2009). Biodiversity creates the unique variety of life on our planet that provides multiple benefits derived from ESS, such as clean air and water, food, health and recreation; it supports pollination and soil fertility, regulates climate and protects us from extreme weather (EC, 2015). In 2011, the European Commission adopted an EU biodiversity strategy to 2020 with the headline target set by EU Heads of State and Government to halt the loss of biodiversity and ecosystem services by 2020, to restore ecosystems, reduce key pressures on EU biodiversity, and step up the EU contribution to preventing global biodiversity loss (EC, 2011, p. 5).
Urban areas are dynamic and complex landscapes, where urbanization effects on vegetation are influenced by socio-ecological processes across multiple scales (Ernstson et al., 2008). Further, the delivery of urban ESS depends on the spatial structure of ecosystems (Alberti, 2005) where biodiversity plays a key role as a regulator of underpinning ecosystem processes (Pelorosso et al., 2016 after Mace et al., 2012). It is therefore suggested that planners, architects and engineers, who take an active part in sustainable urban development are important players, who should understand how they can shape these ascendant ecosystems (Grimm et al., 2008).
Under current processes of densification of urban areas, the alteration in land use is likely to be a major driver of changes in the distribution of ESS (Eigenbrod et al., 2011). A sustainable urban development strives for an optimal relationship between built (grey) and green infrastructure, urban development and the quality, as well as the quantity, of green urban space. Increase of buildings, roads, and industrial areas often corresponds to the increase of impervious surfaces and decrease of green areas. This combined effect of increasing population and loss of permeable surfaces is likely to result in greater and more frequent floods and also loss of habitat for species and biodiversity due to fragmentation of natural habitats and drastic and persistent alteration of habitats (Ahrne et al., 2009).
This is an urgent matter that gains more and more attention in both policy and research (Elmqvist et al., 2013). In Sweden, the concept of urban ESS is currently promoted in the planning for more compact and sustainable cities (Hansen et al., 2015,). However, despite the recognition of the usefulness of the ESS concept, there are many remaining challenges identified by professionals linked to integrating the concept into land use planning and the gap between ESS science and ESS policy (Kaczorowska et al., 2016).
Existing governance and planning systems often suffer from insufficient access to data including relevant tools for assessment and implementation, unpredictable behaviour among humans and ecosystems, and shifting political and individual preferences (Schlüter et al., 2014; Jacobs et al., 2015). We will especially focus on the first in this paper. Representing the science–policy gap in terms of different dimensions of uncertainty appears to provide a more specific and operational approach to seeking out and addressing gaps and weaknesses in these systems.