Assessment of health conditions of main rivers in Renhuai City based on Benthic-integrated biotic index (B-IBI)

Healthy and stable river ecosystem is vital to local biodiversity maintenance and socio-economic development. However, as China's core production area of Maotai-flavor Baijiu, Renhuai City has not established the health assessment system of its main rivers. Thus, we conducted an annual quarterly survey on the benthic fauna at 28 sampling sites in 9 rivers in Renhuai City in 2023, and developed a Benthic-integrated biotic index (B-IBI) health evaluation system for the city's main rivers. The results show that a total of 175 taxonomic units of benthic macroinvertebrates were recorded, belonging to 5 phyla, 10 classes, 22 orders and 75 families. The annual average density and biomass were 1 236.50 ind.·m⁻² and 168.07 g·m⁻², respectively. Among the nine rivers, one was in excellent condition, one was in good condition, three were in average condition, four were in poor condition, none was in very poor condition. Among the 28 sampling sites, two were in excellent condition, five were in good condition, seven were in average condition, seven were in poor condition, seven were in very poor condition. In general, the assessment system of B-IBI in this paper shows that Renhuai City's main rivers are in poor condition, and suitable management and restoration measures should be adopted to make them become healthy again in the future.