Towards an operational methodology to optimize ecosystem services provided by urban soils

Urban soils need to be taken into account by city managers to tackle the major urban environmental issues. As other soils in forest or agricultural environments, urban soils provide a wide range of ecosystem services. However, their contribution remains poorly assessed up to now, and as a result there is a strong lack of consideration by urban planning of the services they provide. Indeed, urban soils are mostly seen as a land surface (land area, two-dimensional system) and if they are characterized, it is almost exclusively for their potential contamination and their geotechnical properties. So, policy makers and planning operators rarely consider soils as a living resource, capable to fulfill essential functions. From the conclusions of previous studies, a selection of ecosystem services provided by soil and adapted to the specificity of urban context is proposed. This paper also aims at proposing the concept of the DESTISOL decision support system for urban planning projects upstream of the planning decisions, illustrated by an application example. It is based on an integrative approach linking soil quality indicators (e.g. physico-chemical and biological characteristics, fertility, pollution), soil functions and soil ecosystem services. The method leads to the semi-quantitative assessment of the level of ecosystem services that are either provided by urban soils or required to fit with the urban design.