Nature-Based Solutions and Nutrient Retention: An Ontological Approach to Support Spatial Planning

Nature-based solutions (NbS) are intentional, strategically planned, and evidence-driven approaches that replicate natural processes to tackle societal challenges. In the last fifteen years, frameworks have been proposed to guide the choice of the most appropriate NbS to address specific challenges, and good practices have been collected in inventories to inspire designers, developers, decision makers, and to foster the uptake of the concept. Academic debates usually focus on NbS in urban areas, while research on their role across broader landscapes remains limited. Therefore, this study addresses this gap by examining NbS that reduce nutrient loads in agricultural settings, with a view to inform planning processes. Drawing on a review of scientific and grey literature, an ontological approach is developed for the taxonomical classification of NbS for nutrient retention in agricultural contexts. This classification outlines key characteristics for each category, including the appropriate spatial scale and level of management, associated benefits and limitations, and an overview of the ecosystem services provided, thus emphasizing the co-benefits and multifunctionality of NbS. The study also highlights challenges related to implementation and integration into planning processes, thereby providing a valuable framework to inform decision-making and enhance the environmental resilience of both urban and regional landscapes.