Multivariate approaches to assess the drivers of benthic macroinvertebrate communities and biotic indices in a highly urbanized fluvial-estuarine system

•Nutrient levels were higher in urban fluvial sections of the Pearl River Estuary.•Macroinvertebrate communities considerably varied along fluvial-estuarine gradient.•AMBI, BENTIX and Δ+ performed better in bioassessment of the Pearl River Estuary.•Water parameters were more important than sediments in shaping macroinvertebrates.