Assessing the performance and sensitivity of benthic indicators under low-level anthropogenic pressures in the eastern Mediterranean

Understanding how benthic communities respond to human-induced pressures is fundamental for successful ecosystem management. However, the effectiveness of benthic indicators in detecting multiple disturbances varies significantly, particularly in areas with relatively low disturbance levels such as the Eastern Mediterranean. This study evaluates the performance and sensitivity of various benthic indicators, including taxonomic diversity, ecological status, risk-based indices and functional diversity metrics, in relation to two human-induced pressures: trawling intensity and organic enrichment. Using effect size analysis and machine-learning approaches, we evaluated first how different indicators respond to changes in total organic carbon and trawling intensity and then assessed the relative importance of predictors under low-disturbance conditions. The results revealed that none of the tested indicators adequately captured simultaneously the effects of both pressures. In addition, the environmental covariates had a stronger influence on predicting the indicators than the two pressures. The findings demonstrate that no single indicator can fully capture the response to multiple stressors, especially under low-level pressures and underscore the importance of natural covariates, such as depth and/or sediment characteristics, in the interpretation of benthic indicators.