Cystoseira sensu lato (s.l.) macroalgal forests are among the most complex and productive ecosystems along the rocky coasts of the Mediterranean Sea. They provide food and shelter to a wide range of organisms and provide essential ecosystem services, including carbon sequestration and protection from coastal erosion. However, in recent years, these habitats have declined significantly in many areas of the Mediterranean, mainly due to human impacts such as coastal urbanization and water pollution.

This study is part of the European LIFE project “REEForest,” which aims to restore Cystoseira s.l. in the Marine Protected Area (MPA) of Santa Maria di Castellabate. An environmental accounting model was applied to calculate the biophysical value of natural capital (NC) in subtidal rocky habitats, both in the donor and receiving sites involved in the restoration activities. This approach allows for quantifying the biotic stocks of NC and serves as a foundation for assessing the flows of ecosystem services and the impacts associated with  their use. Results show that the NC at the donor sites of Punta Licosa is 2.95×10¹²± 2.36×10¹¹ sej/m², while at the receiving sites of Punta Pagliarola it reaches 3.38×10¹²± 4.46×10¹¹ sej/m². These differences reflect the environmental characteristics of the two areas, as well as the different protection regimes within the MPA. The environmental accounting model was implemented based on samples collected during the winter survey, but the study will be further developed with data from the spring/summer survey, the vegetative growth season of Cystoseira s.l.

In conclusion, this study highlights the ecological importance of Cystoseira s.l. habitats and the value of environmental accounting as a tool for planning effective long-term protection, conservation, and restoration strategies.