Habitat suitability models as a prioritization tool for enhancing the restoration success of Ericaria amentacea

Ecological restoration is increasingly recognized as crucial for addressing global environmental challenges, including biodiversity loss, ecosystem degradation and climate change. Restoration efforts, such as those outlined in the European Biodiversity Strategy and the UN Sustainable Development Goals, are gaining momentum worldwide. Additionally, the EU recently put into force Regulation (EU) 2024/1991 on Nature Restoration, that sets ambitious targets for restoring degraded habitats.

In the Mediterranean, brown macroalgae belonging to the Cystoseira s.l. complex (including Cystoseira, Gongolaria, and Ericaria) play an important role as “ecosystem engineers” in coastal habitats, although their populations have declined due to anthropogenic pressures. Restoration efforts are essential to support the conservation of the forests they form. In this context, Habitat Suitability Models (HSMs) provide an effective tool for guiding restoration strategies by mapping the distribution of suitable habitats. By establishing correlations between species distribution and environmental conditions, HSMs provide insights into potential restoration sites, enhancing conservation efforts. In this regard, this study develops a habitat suitability model (HSM) for the species Ericaria amentacea along the Ligurian coast (NW Mediterranean). Using presence-absence data combined with environmental and anthropic variables, the Random Forest algorithm predicted 1201sectors suitable for E. amentacea while only 313 sectors are verified on field. The Habitat Quality model (INVEST Workbench), along with an assessment of proximity to harbors and marinas, was used to further refine and prioritize the sectors predicted by the model that are most likely to succeed in restoration effort, based on accessibility and habitat quality. These findings offer a valuable tool for enhancing biodiversity conservation and restoration efforts in Mediterranean coastal ecosystems.