Macrobenthos Diversity Response to Hydrological Connectivity Gradient

The abundant riparian wetlands supported by the complex river network in Pearl River Delta (PRD) are under an intensely anthropogenic disturbance that threatens the local ecological environment. This paper examined the benthic invertebrate diversity and biomass within the Pearl River through a field study. A fieldwork was conducted to assess a hydrological connectivity gradient among the main channel of the Pearl River. The responses of macroinvertebrate metrics to the connectivity gradient and the restoration history in the river channel were examined. The Shannon diversity index ranged from 0.75 to 2.08, which was the highest among most connectivity river channels. Statistical analyses (PCA and CCA) revealed that the benthic abundance in high hydrological connectivity riverine habitats is clearly distinct from the low connectivity habitats. Results demonstrated that the diversity and density of macrobenthos are determined by hydrological connectivity and time span of the restoration (river channels). Therefore, conservation and restoration efforts should focus on the macroinvertebrate response to the hydrological connectivity of the river channels in PRD.