Conference Agenda

Marine ecosystems provide a wide range of ecosystem services that are fundamental to human well-being, including food provision, climate regulation, and cultural benefits. However, these ecosystems are increasingly threatened by climate change and intensifying anthropogenic pressures, leading to a progressive erosion of their capacity to sustain ecological functions and societal benefits. In this context, the development of robust and policy-relevant framework for monitoring marine natural capital and its associated ecosystem services has become an urgent priority. However, the practical implementation of marine ecosystem accounts remains limited, fragmented, and methodologically heterogeneous.

This paper contributes to this agenda by implementing the System of Environmental-Economic Accounting—Ecosystem Accounting (SEEA EA) framework to compile marine ecosystem accounts for Posidonia oceanica, a key seagrass species in the Mediterranean Sea. We focus on Italy as a national case study and integrate three major ecosystem services: fish provisioning, carbon sequestration, and marine-based recreation. We adopt a dual methodological strategy, combining a top-down national-level approach with a bottom-up regional implementation, using Sardinia as illustrative case studies. This dual approach allows us to explicitly examine how scale, data availability, and methodological choices affect the reliability, interpretability, and policy relevance of marine ecosystem accounts.

In addition, we extend the application of ecosystem accounting beyond descriptive stock and flow measures by integrating marine natural capital into the Genuine Savings (GS) indicator. This extension enables an assessment of whether observed economic growth trajectories are achieved at the expense of marine ecosystem degradation or are compatible with long-term sustainability.

Our results demonstrate that it is feasible to compile both physical and monetary accounts for marine ecosystems within a standardized accounting framework. However, they also reveal significant challenges related to data quality, spatial resolution, temporal consistency, and institutional fragmentation. We show that national-level accounts may obscure important local dynamics, while bottom-up approaches, although more ecologically grounded, face limitations in comparability and scalability. The integration of marine natural capital into GS further highlights how ecosystem degradation can alter sustainability assessments, with important implications for regional and national policy priorities.

Overall, this study provides a structured, transparent, and replicable framework for other habitats within the marine ecosystem accounting context, while critically reflecting on its limitations. By explicitly addressing issues of scale, uncertainty, and data gaps, we argue that acknowledging these constraints does not weaken the credibility of ecosystem accounting; rather, it strengthens its role as a decision-support tool for marine conservation, spatial planning, and sustainable development.