A novel assessment framework for Nature-based Solutions in Mediterranean agro-silvo-pastoral ecosystems

Mediterranean agro-silvo-pastoral ecosystems (MAEs) are increasingly affected by water scarcity, rising temperatures, drought, and land-use change, all of which reduce water availability and system resilience. These combined pressures threaten long-term ecological and economic sustainability by contributing to declining profitability, land abandonment, and land degradation. Collectively, these processes reduce ecosystem functions and the capacity for carbon sequestration.

The Horizon Europe DRYAD project ("Demonstration and modelling of nature-based solutions to enhance the resilience of Mediterranean agro-silvo-pastoral ecosystems and landscapes") advances current knowledge by designing and implementing evidence-based, scientifically validated, and community-tailored nature-based solutions (NbS) in selected Pilot Demonstration Areas. The project explicitly addresses the hydrological and socio-ecological complexity of MAEs under multiple risk conditions. DRYAD employs an expanded interpretation of NbS, conceptualizing them as an "ecosystem of NbS" that includes intervention-, protection-, management-, and planning-oriented actions functioning in systemic interaction.

One of DRYAD’s tasks is to develop a novel, standardized framework addressing a key limitation in current NbS implementation in agro-silvo-pastoral ecosystems: the lack of information, thereby enabling wider upscaling and mainstreaming. The framework, termed NbS Abacus, is implemented through the systematic documentation and evaluation of thirteen NbS using comprehensive fact sheets developed with stakeholder input. Each NbS is assessed against a set of characteristics, including implementation requirements, targeted ecosystem services (classified according to the Common International Classification of Ecosystem Services), expected benefits, potential trade-offs, strengths, constraints, costs, policy relevance, and upscaling potential. While all NbS are multifunctional, they are classified according to their primary ecosystem service focus into water-, soil-, and biodiversity-related interventions.

Water-related NbS address key hydrological constraints in MAEs, such as strong precipitation seasonality and prolonged summer droughts. Examples include contour-aligned drainage ditches, dry detention ponds, and artificial ponds. The framework explicitly captures associated risks. These include, e.g., substrate clogging and groundwater contamination from polluted runoff. This enables risk-informed NbS design, implementation, and the selection of appropriate monitoring protocols and indicator sets.

MAEs have also experienced increasing degradation driven by contrasting land-use dynamics, notably land abandonment and intensification. Soil-related NbS aim to improve land management efficiency by enhancing soil water retention, fertility, and erosion regulation. Representative examples include adaptive grazing schemes, real-time livestock monitoring systems, and wildfire prevention measures.

Climate-induced drought poses a major threat to biodiversity in MAEs. Biodiversity-related NbS aim to restore or conserve ecological functioning through measures such as strategic forestation, agropastoral system reforestation, habitat islands, and remote sensing-based detection of tree decline. The framework accounts for both long-term ecological benefits and short-term socio-economic constraints, including infrastructure requirements, site biophysical limitations, maintenance costs, forage yield reductions, and temporary impacts on livestock productivity.

The NbS Abacus supports the uptake of NbS by providing harmonized, practice-oriented information on performance, costs, risks, and scalability. The framework and its NbS catalogue facilitate informed decision-making, replication, and mainstreaming across land management and climate adaptation strategies, with relevance for practitioners, advisors, policy-makers, and planners in Mediterranean and other drought-prone regions.

Acknowledgements. This research has received funding from the European Union’s Horizon Europe research and innovation programme under Grant Agreement No. 101156076 (DRYAD).