Identifying functional hotspots for Nature-based Solutions: a meta-ecosystem approach to multi-risk mitigation in Cantabria (Spain)

Climate change is intensifying floods, soil erosion and wildfires across Europe, while ongoing biodiversity loss is progressively weakening the capacity of ecosystems to regulate the biophysical processes underpinning these risks. Nature-based Solutions (NbS) offer a way to jointly address climate adaptation and biodiversity conservation, but their effectiveness critically depends on where they are implemented within heterogeneous landscapes. This study presents a regional-scale framework to identify and prioritise functional hotspots for NbS implementation in Cantabria (northern Spain), explicitly targeting multi-risk regulation and ecosystem service (ES) synergies.

The approach builds on the NBRACER conceptual framework and adopts a meta-ecosystem perspective to connect climate risk assessment with ecosystem-based regulation. From a biophysical standpoint, high-resolution spatial datasets and process-oriented models are used to characterise flood, erosion and wildfire hazards, map biodiversity distribution, and assess the capacity of ecosystems to regulate key biophysical flows involved in risk propagation and impact generation (e.g. surface runoff, sediment transport, water storage and fire spread). Biodiversity underpins this assessment by structuring ecosystem functions through vegetation types, functional traits and landscape configuration, which are translated into spatially explicit ES indicators derived from geomorphological, hydrological and ecological variables.

Risk relevance is reinforced by integrating the social dimension through the identification and prioritisation of Key Community Systems (KCS) exposed to hazards. This enables the explicit linkage between ecosystems acting as ES supply areas and service-benefiting areas where impacts need to be buffered. This exercise allows identifying both the range of potential NbS that could be deployed in the landscape and the existing ecological capital available to reduce risks affecting social systems.

Functional hotspots are then identified and prioritised based on their capacity to simultaneously regulate multiple risks and reduce impacts on exposed KCS. The methodology allows the identification of which ecosystems (e.g. hillslope forests, floodplains, riparian forests, forest plantations, shrublands) should be targeted for management actions—ranging from conservation and restoration to sustainable management practices—to enhance ES linked to risk reduction. A central objective is to restore functional ecological connectivity across ecosystems, enabling the synergistic regulation of multiple risks through coordinated action on interconnected biophysical processes.

The resulting functional hotspot maps and regional NbS strategies provide actionable insights for planners and decision-makers. By linking high-resolution ecological modelling with risk governance needs, the framework supports stakeholder engagement, transparent prioritisation, and policy-relevant NbS deployment aligned with regional adaptation strategies.