In the context of the NBFC (National Biodiversity Future Center), the MARES (Marine Ecosystem Restoration) project, financed through European Union funds, has developed standardized protocols for the restoration of a suite of degraded marine ecosystems under different socio-ecological settings.

Ecosystem restoration is a key activity necessary to maintain natural capital and ensure the provisioning of ecosystem services at least at current levels. This is now regulated in Europe through the Nature Restoration Law, a key element of both the European Green Deal and the EU Biodiversity Strategy.

However, artificially reconstructing the complexity of ecosystems created by nature may require the use of both renewable and non-renewable resources, as well as result in the generation of waste, which must be minimized from a sustainability perspective. Therefore, the development of protocols and guidelines must consider these aspects and integrate environmental accounting approaches to evaluate sustainability performance, with the aim of continuous improvement.

For this reason, within the MARES project, the environmental sustainability of a selection of case studies has been assessed. The ecosystems considered include: Posidonia oceanica meadows, Ericaria amentacea macroalgal forests, Ostrea edulis reefs, and vermetid (Dendropoma cristatum) reefs.

Sustainability was assessed by means of a system methodology known as emergy analysis which accounts for all the resources used in a process in a single unit of measure: solar emergy joule (seJ). This approach allows for the comparison of different inputs and phases within a single restoration process, as well as between different processes. Furthermore, sustainability indices were calculated to compare the various case studies. When possible, the value of the resources used was compared to the value of the restored natural capital.

The results represent a practical tool to evaluate different restoration processes and to highlight the importance of conserving both natural and restored ecosystems.