Testing the applicability of biotic indices to assessing the sandy beaches health in Rio de Janeiro, Southeast Brazil

We tested the suitability of the AMBI, BENTIX, and Benthic Pollution Index (BPI) to evaluate the ecological status of 68 sandy beaches of Rio de Janeiro State, grouped into seven regions. We also tested the hypothesis that these indices are sensitive to urbanization levels and the intensity of recreation facilities on beaches. Results reflected the main impacts that sandy beaches suffer, with slight pattern variations. The only exception was the BPI index, which overestimated the ecological status of many beaches classified by AMBI and BENTIX as good and moderate. The overall pattern of ecological status revealed that urbanization effects and the percentage of sewage treated are significant sources of beach impacts in Rio de Janeiro State. Overall, our study highlighted the utility of these indices in assessing human impacts on sandy beaches and underscored their potential to guide targeted management and conservation efforts in coastal ecosystems. Based on our results, we recommend BENTIX as the primary index for assessing the ecological status of sandy beaches, particularly in areas under organic pollution and urban pressure.