A cross-scale ecosystem services framework to assess Nature-based Solutions for drought adaptation

Nature-based Solutions (NbS) are increasingly promoted as key strategies for climate change adaptation, particularly in drought-prone regions where water scarcity, ecosystem degradation and socio-economic vulnerabilities interact across spatial and institutional scales. As emphasized by IPCC and IPBES, effective adaptation has to jointly address climate risks and biodiversity loss, while explicitly accounting for governance structures, equity and different vulnerability. However, current NbS assessments often focus on biophysical performance, overlooking cross-scale governance dynamics and the distribution of ecosystem services benefits and costs.

This contribution presents a cross-scale ecosystem services modelling framework developed within the NBS4Drought project (Horizon Europe - Grant No. 101181351) to support the assessment of NbS for drought adaptation in complex social–ecological systems. Grounded in ecosystem services research and social–ecological systems theory, the framework conceptualizes NbS as embedded interventions whose outcomes depend on interactions between ecological processes, social actors and decision-making structures operating across scales.

The proposed modelling framework integrates four interconnected analytical components: (i) identification of drought-relevant ecosystems and associated provisioning, regulating and cultural ecosystem services; (ii) mapping of social actors involved in NbS use, management and regulation across spatial and institutional scales; (iii) assessment of actors’ dependence on ecosystem services and their capacity to influence NbS-related decision-making; and (iv) analysis of cross-scale interactions, power asymmetries and governance mismatches shaping NbS effectiveness. This structure directly responds to IPCC and IPBES calls to operationalize equity, enabling the evaluation of both procedural equity (who participates in decisions) and distributive equity (who benefits from NbS outcomes), as well as actors’ vulnerability to drought under changing climatic conditions.

To explicitly capture system complexity, feedback mechanisms and non-linear dynamics, the framework is operationalized through participatory System Dynamics (SD) modelling, used to jointly explore and structure stakeholders’ understanding of how drought processes, NbS interventions and ecosystem services interact over time. SD modelling enables the exploration of cross-scale feedbacks between ecological processes, management decisions and governance structures, addressing key limitations highlighted in recent global assessments (e.g., static representations, sectoral silos and limited consideration of feedbacks and non-linear responses).

By linking these dynamic representations to ecosystem services and governance analysis, the framework supports the identification of scale mismatches, co-benefits and trade-offs between drought adaptation, biodiversity conservation and human well-being, including potential spatial disconnections between ecosystem service production and beneficiaries under climate change.

The proposed modelling framework aims to provide a transferable analytical basis to support more robust, inclusive and context-sensitive NbS pathways for drought adaptation.