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Green roofs

What drives variation in ecosystem services among artificial green roofs ?
Green roofs provide ecosystem services through evapotranspiration and nutrient cycling that depend, among others, on plant species, substrate type, and substrate depth. However, no study has assessed thoroughly how interactions between these factors alter ecosystem functions and multifunctionality of green roofs. Using pots to simulate green roof conditions, a team of researchers from iEES Paris examined differences in ecosystem functiong among artificial microcosms differing in plant species (20 species), substrate types (natural vs. artificial) and substrate depths (10 cm vs. 30 cm). Results of this experiment done in the greenhouse of CEREEP-Ecotron indicated that no single combination of factors enhanced simultaneously all studied ecosystem functions, highlighting that soil–plant interactions induce trade-offs between ecosystem functions. Substrate type and depth interactions were however major drivers for green roof multifunctionality. This research will help make recommandations to design more sustainable and rewarding green roofs.