Climate-resilient systems prioritisation index: A spatial framework for multi-hazard mitigation via nature-based solutions

This article presents the Climate-Resilient Systems Prioritisation Index (CRESPI), a GIS-based spatial decision-support framework developed to support climate resilience planning through the prioritisation of Nature-based Solutions (NbS). Grounded in a Complex Adaptive System of Systems (CASoS) perspective, CRESPI conceptualises landscapes as interdependent socio-economic, ecological and infrastructural systems. Resilience is operationalised through the analysis of Key Community Systems (KCS), including infrastructure, mobility, social and health services, economic activities, populations, and ecosystems. CRESPI integrates flood exposure with indicators of social vulnerability, infrastructure criticality, economic sensitivity, and ecological context. Pluvial and fluvial hazards are represented using flood-depth data, while system interdependencies are identified through spatial convergence analysis. Indicator weighting is implemented using the Analytic Hierarchy Process (AHP), following a protection-oriented rationale that prioritises human safety, service continuity, and compound risk conditions. 

The results show that CRESPI can effectively distinguish between areas with constrained absorptivecapacity, limited adaptive redundancy, persistent high-risk conditions requiring transformativeresponses, and socially sensitive zones where recovery may be compromised. By combining conver-gence mapping with ecosystem connectivity indicators and NbS effectiveness layers, the frameworksupports differentiated adaptation strategies across urban, peri-urban, and rural contexts, aligning NbSportfolios with functional system interactions rather than applying uniform measures across space.Future applications could further refine this prioritisation by incorporating biodiversity-sensitivezones, including habitats of Red List species and areas protected under the EU Birds and Habitats Directives, allowing spatial units to be flagged for ecological safeguards or elevated restoration prioritywithin the GIS.