Marine caves are unique and vulnerable habitats exhibiting high biodiversity and heterogeneity, but threatened by multiple global and local disturbances. Marine caves, although widely distributed along the Mediterranean coast, suffer for the lack of quantitative data on their structure and function, which hinder their conservation status assessment.

This study analysed a 30 year data series of quantitative information about the sessile communities in the Bergeggi marine cave (Ligurian Sea, NW Mediterranean), elucidating the evolution of the cave ecosystem through the studied period. The analysis was undertaken adopting growth forms (morphology) and feeding strategies as descriptors, which provide information about ecosystem structure and functioning.

The results show that the cave experienced a general trend of change during the last three decades, mainly due to the decline in the cover of structural and functional homogenization of the cave community.

The authors highlight that changes before 2004 can be mostly attributed to climatic factors like the heatwaves of 1999 and 2003. However, they found that the most important rate of change was observed between 2009 and 2013, in coincidence with recent major beach nourishments and the extension of the neighbouring Vado Ligure harbor, thus providing evidences on the importance of local disturbances deriving from coastal interventions.

The authors underline that monitoring the status of the highly fragile cave ecosystems is urgently needed, and state that the use of effective indicators, such as those adopted in the study, could provide efficient tools to assist marine cave conservation.

Montefalcone et al. (2018) Thirty year ecosystem trajectories in a submerged marine cave under changing pressure regime. Marine Environmental Research 137:98-110