Large-scale assessment of non-indigenous macroalgae in Mediterranean sensitive habitats: Toward a standardized...

A standardized procedure for assessing the ecological quality of sensitive habitats in relation to biological invasions by macroalgae, based on the ALien Biotic IndEX, has recently been proposed. This study aims to test the procedure on a large spatial scale and to optimize the methodology for its application in monitoring programs across different biogeographical areas. The procedure was tested on coralligenous reefs and Posidonia oceanica seagrass meadows at different spatial scales, both in protected and unprotected areas. The results highlighted no significant effect of protection regime on the presence and abundance of non-indigenous species (NIS). Furthermore, NIS spread was found to be strongly dependent on the habitat type and species involved. Additionally, the findings suggest latitudinal difference in the seasonal dynamics of Caulerpa cylindracea. Overall, the study confirmed the robustness and applicability of the method under different conditions tested, indicating its suitability as an effective monitoring tool for standardizing sampling and data required to optimize NIS management.