Advancing star: A revised protocol for assessing the ecological status of coralligenous cliffs

Abstract

The STAR protocol was recently proposed to standardise sampling methods for assessing the ecological quality of coralligenous cliffs through the three indices ESCA, ISLA and COARSE. In this paper, a revised version of the STAR protocol was proposed to enhance its robustness and effectiveness. Compared to the previous one, this new proposal includes the use of video transects for a more accurate assessment of erect anthozoans, the development of a new ESCA (n-ESCA) index independent of the encrusting coralline algae and integrated with the ISLA index, and the creation of the IICA index calculated averaging n-ESCA and COARSE. The new STAR protocol was applied to 28 sites in the western Mediterranean Sea and the ecological status obtained from all the indices (ESCA, ISLA, COARSE, n-ESCA, IICA) were compared to the human pressure levels calculated by an anthropization index. The n-ESCA showed a stronger correlation compared to the ESCA, COARSE and ISLA indices, indicating a better response of this new index to anthropogenic pressures affecting the investigated coralligenous. Moreover, the correlation obtained for the IICA was stronger than that showed individually by the n-ESCA and COARSE indices, further supporting the advantage of integrating multiple ecological descriptors for a more comprehensive evaluation. The advanced STAR protocol overcome the constraints emerged over several years of large-scale application of the previous version, offering a more robust and sensitive tool that can effectively capture both fine-scale and broader ecological changes in coralligenous habitats.