Nature-based solutions in the urban context: terminology, classification and scoring for urban challenges and ecosystem services

J A C Castellar; L A Popartan; J Pueyo-Ros; N Atanasova; G Langergraber; I Säumel; L Corominas; J Comas; V Acuña

doi:10.1016/j.scitotenv.2021.146237

Nature-based solutions in the urban context: terminology, classification and scoring for urban challenges and ecosystem services

Sci Total Environ. 2021 Jul 20:779:146237. doi: 10.1016/j.scitotenv.2021.146237. Epub 2021 Mar 5.

Authors

J A C Castellar¹, L A Popartan², J Pueyo-Ros³, N Atanasova⁴, G Langergraber⁵, I Säumel⁶, L Corominas³, J Comas⁷, V Acuña³

Affiliations

¹ Catalan Institute for Water Research (ICRA), Carrer Emili Grahit 101, 17003 Girona, Spain; University of Girona, Plaça de Sant Domènec 3, 17004 Girona, Spain. Electronic address: jcastellar@icra.cat.
² LEQUIA. Institute of the Environment, University of Girona Campus Montilivi, carrer Aurèlia Capmany, 69 E-17003 Girona, Catalonia, Spain.
³ Catalan Institute for Water Research (ICRA), Carrer Emili Grahit 101, 17003 Girona, Spain; University of Girona, Plaça de Sant Domènec 3, 17004 Girona, Spain.
⁴ University of Ljubljana, Faculty of Civil and Geodetic Engineering, Jamova 2, 1000 Ljubljana, Slovenia.
⁵ Institute of Sanitary Engineering and Water Pollution Control, University of Natural Resources and Life Sciences, Vienna (BOKU), Muthgasse 18, A-1190 Vienna, Austria.
⁶ Integrative Research Institute on Transformations of Human-Environment Systems (IRI THESys), Humboldt Universität zu Berlin, Unter den Linden 6, D-10099 Berlin, Germany.
⁷ Catalan Institute for Water Research (ICRA), Carrer Emili Grahit 101, 17003 Girona, Spain; LEQUIA. Institute of the Environment, University of Girona Campus Montilivi, carrer Aurèlia Capmany, 69 E-17003 Girona, Catalonia, Spain.

PMID: 34030251
DOI: 10.1016/j.scitotenv.2021.146237

Abstract

The concept of Nature-Based Solutions (NBS) has emerged to foster sustainable development by transversally addressing social, economic, and environmental urban challenges. However, there is still a considerable lack of agreement on the conceptualization of NBS, especially concerning typologies, nomenclature, and performance assessments in terms of ecosystem services (ES) and urban challenges (UC). Therefore, this article consolidates the knowledge from 4 European projects to set a path for a common understanding of NBS and thus, facilitate their mainstreaming. To do so, firstly, we performed elicitation workshops to develop an integrative list of NBS, based on the identification of overlaps among NBS from different projects. The terminologies were formalized via web-based surveys. Secondly, the NBS were clustered, following a conceptual hierarchical classification. Thirdly, we developed an integrative assessment of NBS performance (ES and UC) based on the qualitative evaluations from each project. Afterwards, we run a PCA and calculated the evenness index to explore patterns among NBS. The main conceptual advancement resides in providing a list of 32 NBS and putting forward two novel NBS categories: NBS units (NBS_u) that are stand-alone green technologies or green urban spaces, which can be combined with other solutions (nature-based or not); NBS interventions (NBS_i) that refer to the act of intervening in existing ecosystems and in NBS_u, by applying techniques to support natural processes. The statistical analysis suggests that NBS_u are more versatile than NBS_i in terms of UC and ES. Moreover, the results of the integrative assessment of NBS performance suggest a greater agreement concerning the role of NBS in addressing environmental UC, cultural and regulating ES than regarding socio-economic UC and supporting and provision ES. Finally, the 'green factor' and the replication of non-intensive practices occurring in nature seem to be key criteria for practitioners to identify a particular solution as an NBS.

Keywords: Cities; Clustering; Definition; Evaluation; NBS; Nomenclature.