Spatial distribution of benthic macroinvertebrate community in a sediment-laden river:Influence of anthropogenic activities and land use changesOA

River ecosystems experience biodiversity loss due to intensifying anthropogenic disturbance and land use change.Although macroinvertebrate community plays a critical role in sustaining biogeochemical cycling and river ecosystem stability,the extent to which anthropogenic activities and land use changes affect macroinvertebrate biodiversity and sediment ecological health remains insufficiently resolved.This study investigated the effects of anthropogenic activities and land use changes on macroinvertebrate community diversity in the Beiluo River Basin,China.An entropy-based framework was developed to evaluate sediment ecological health.A total of 31 phyla were identified,with Annelida(1.26%–71.95%)and Arthropoda(8.25%–24.17%)as the dominant groups.The entropy values indicated that macroinvertebrate community diversity across the 18 sampling sites was the highest in the middle reaches.Mineral extraction and excessive fertilizer application in the upper and middle reaches were notably associated with sediment degradation.The expansion of riparian cropland and industrial pollution reduced benthic macroinvertebrate abundance,whereas a higher proportion of riparian water bodies buffered pollutant inputs and provided habitat refuges,thereby supporting higher macroinvertebrate abundance.In addition,hydraulic engineering and wetland conservation measures increased the diversity of Mollusca and Rotifera,reflecting positive ecological responses to policy-driven restoration.Overall,the entropy-based sediment ecological quality index(SEQI)integrating sediment chemistry with deoxyribonucleic acid(DNA)metabarcoding diversity indicated that the sediment eco-quality in the Beiluo River Basin was primarily constrained by riparian land use and catchment-scale anthropogenic pressure.Partial Least Squares-Path Modeling(PLS-PM)explained 69.30%of the variance in SEQI(goodness of fit(GOF)=0.519)and revealed that land use exerted a stronger effect on SEQI than socioeconomic factors.These findings highlight the need to curb the expansion of riparian cropland and built-up land,reduce pollutant discharges,sustain the protection of water bodies and wetlands including continued water,conservation investment,and improve wastewater treatment to protect sediment quality and benthic biodiversity.Collectively,these results provide an important basis for assessing river ecological health and informing sustainable regional socioeconomic development.