Integrating natural capital assessment and marine spatial planning: A case study in the Mediterranean sea

- Natural capital value was assessed in the Egadi islands MPA through emergy accounting.
- The value of both autotrophic and heterotrophic natural capital stocks was calculated.
- Marxan software was used to identify key areas for natural capital conservation.
- Environmental accounting outcomes were integrated with spatial data on human uses.
- Marine spatial planning considered both conservation targets and human activities.

Marine and coastal ecosystems are among the most productive environments in the world and their stocks of natural capital offer a bundle of vital ecosystem services. Anthropogenic pressure seriously threatens health and long-term sustainability of marine environments. For these reasons, integrated approaches capable of combining ecological and socio-economic aspects are needed to achieve nature conservation and sustainability targets. In this study, the value of natural capital of the Egadi Islands Marine Protected Area (EI-MPA) was assessed through a biophysical and trophodynamic environmental accounting model. The emergy value of both autotrophic and heterotrophic natural capital stocks was calculated for the main habitats of the EI-MPA. Eventually, the emergy value of natural capital was converted into monetary units to better communicate its importance to local managers and policy-makers. The total value of natural capital in the EI-MPA resulted in 1.12·1021 sej, equivalent to about 1.17 billion of euros. In addition, using Marxan software, the results of the environmental accounting were integrated with spatial data on main human uses. This integration took into account the trade-offs between conservation measures and human exploitation by means of two different scenarios, with and without considering human uses in the EI-MPA. The comparison between the scenarios highlighted the importance of taking into account human activities in marine spatial planning (MSP), allowing the identification of key areas for natural capital conservation. In conclusion, this study showed the importance of integrating environmental accounting with conservation planning to support effective strategies for ecological protection and sustainable management of human activities. The results of this study represent a first benchmark useful to explore alternative nature conservation strategies in the EI-MPA, and, more in general, in Mediterranean MPAs.