Abstract
Coralligenous reefs characterize the circalittoral zone of the Mediterranean Sea, but, in many areas, they are also distributed within the infralittoral zone. Despite their wide distribution, the infralittoral coralligenous reefs are less considered in monitoring programs and no specific methods have yet been developed for their assessment. This study aims at testing a modified ESCA index (I-ESCA) on the infralittoral coralligenous reefs in order to propose a new tool suitable to evaluate the ecological quality of this habitat. Thirteen sites were sampled in the western Mediterranean Sea and the relationship between I-ESCA and the Anthropization Index was tested with a regression model in order to evaluate the response of the index to human pressures. Infralittoral coralligenous assemblages were dominated by macroalgae, while the bryozoan Myriapora truncata and the cnidarian Parazoanthus axinellae were the most widespread animals. The I-ESCA index allowed to highlight the level of human pressures of the sites similarly to ESCA. Thus, results of this study suggested the possibility of applying the index also to the infralittoral habitat using an adequate calibration of the original method on the new spatial scale and reference conditions.