Baseline for marine cave monitoring strategies in the Alboran Sea using modified Cave Ecosystem-Based Quality Index (CavEBQI).

Marine caves constitute vulnerable habitats with unique and diverse biocoenoses. Monitoring these habitats is still challenging, which hinders the ability to evaluate global and local pressures that threatens their ecological value. In this study, ecological quality is estimated in twenty-one marine caves distributed along the northern and southern coasts of the Alboran Sea, a highly understudied area regarding marine caves. For that purpose, adjustments on the original Cave Ecosystem Based Quality Index (CavEBQI) are suggested in order to efficiently estimate the ecological quality of marine caves. Several methodological aspects regarding the assessment of biotic coverage, the visual census of motile fauna and the plasticity of the index usability were evaluated. Ecological quality of marine caves was in average "good" although it ranged between "poor", "moderate" and "good" depending on the features of each cave. This study emphasizes the importance of adapting biotic indicators to biogeographical differences and technological advancements. • Twenty-one marine caves in the Alboran Sea showed positive results in biotic coverage, species richness, and quality. • The CavEBQI indicator was adapted, offering a reliable, efficient method for assessing marine cave quality. • Adapted index streamlined biotic coverage analysis from photoquadrats and included an array of target motile species. • The adapted CavEBQI provided more precise results, making it more sensitive to changes in cave-dwelling communities. • A good insight into cave-dwelling communities of the Alboran Sea is provided. [ABSTRACT FROM AUTHOR]