Community characteristics of macrobenthos and ecosystem health assessment in ten reservoirs of Henan Province, China

Assessing the eco-health of regional reservoirs is essential for sustainable water resource utilization and water security, particularly in water-scarce areas. This study constructed a Benthic Index of Biotic Integrity (B-IBI) based on the community characteristics of macrobenthos in ten large and medium-sized reservoirs across four major river basins in Henan Province, China. A total of 90 taxa were identified, representing 3 phyla, 6 classes, 17 orders, 45 families and 81 genera. The B-IBI was derived from five key metrics: the number of crustacean and mollusca taxa, Intolerant %, the BI index, the BMWP index, and the Shannon-Wiener index. The B-IBI scores across 44 sites in the ten reservoirs ranged from 0.35 to 3.99. The assessment classified two reservoirs (QTH and HKC in the Yellow River basin) as poor, whereas one reservoir (QP in the Huai River sbasin) was classified as excellent. The B-IBI index effectively distinguished impaired sites from reference sites, supporting its suitability for eco-health assessments of reservoirs in Henan Province.