Suitability mapping for the implementation of Nature-based Solutions in marine and coastal areas

Elena Allegri^1,2Emma Chiara Miglio²Elisa Furlan^1,2*Jordan Bishop^1,2Remy Simide³Antonio Marcomini^1,2Andrea Critto^1,2

• ¹Foundation Euro-Mediterranean Center on Climate Change (CMCC), Lecce, Italy
• ²Department of Environmental Sciences, Informatics and Statistics, Ca 'Foscari University of Venice, Venice, Veneto, Italy
• ³Institut Océanographique Paul Ricard, Île des Embiez, France

Environmental risks are intensified by the growing interaction between human-induced and climate change (CC) pressures, leading to biodiversity loss and ecosystem changes, which threaten the resilience and health of marine-coastal ecosystems (MCEs). The increasing risks posed by CC require appropriate adaptation actions, that can boost biodiversity, while benefiting people. In this setting, NBS play a crucial role in coping with climate impacts by improving ecosystems resilience, protecting, restoring natural ecosystems while providing benefits for human well-being. Current literature mainly focuses on NBS in terrestrial environments, showing a limited knowledge on their implementation (and effectiveness) in marine-coastal environments. Particularly, there is a lack in the analysis of suitable conditions for their successful implementation in marine-coastal areas, when considering environmental, socio-economic and governance aspects, with the concept of ‘suitability’ characterized by the absence of a consolidated and recognized definition. Through a systematic approach, this review work aims at reducing uncertainty surrounding the concept of suitability, providing guidance for its interpretation and application in real-world NBS design and implementation. Hence, it investigates the state-of-the-art scientific literature on methodologies, modelling tools, analytical frameworks, and approaches assessing NBS suitability in MCEs. From a pool of 26 papers covering 2011-2025 timeframe, a period selected to align with the emergence and formalisation of the NBS concept, the review confirmed that a unique and shared definition of suitability is missing. In this frame, the concept has been extrapolated from a selection of key papers, drawn from the literature. Furthermore, the review revealed that environmental indicators (e.g., slope, depth and SST) are the most used for analysing suitability, followed by socio-economic indicators (e.g., land use and distance from the coast, hence those proxies that reflect human activities or infrastructures). However, socio-economic and governance dimensions remain poorly explored in the investigated publications, rather, methodological approaches mainly focused on environmental aspects able to frame optimal physical, ecological, and chemical conditions for NBS implementation are deepened. From the literature it appears that suitability models represent an essential decision-making tool to drive nature-based adaptation in marine-coastal areas, as fundamental to guarantee the successfulness of implemented NBS or the restoration and preservation of ecosystems.