ABSTRACT Aquatic biodiversity is widely used as a bioindicator for freshwater ecosystem health, yet its relationship with water quality in naturally high‐quality rivers remains unclear. To address this, the Chishui River, an undammed river with a natural flow regime, was investigated. Samples of phytoplankton, zooplankton and benthic macroinvertebrates were collected across wet (2023), normal (2023) and dry (2024) seasons, along with key water quality parameters and hydrological variables. Using generalized additive models (GAMs), variance partitioning analysis (VPA), Spearman correlation analysis and random forest (RF) analysis, complex, non‐linear responses of aquatic biodiversity to key water quality parameters were demonstrated, indicating that using aquatic biodiversity as a sole water quality proxy may be misleading. Hydrological variables explained 2.78%–16.37% of variance in aquatic biodiversity indices, with water temperature negatively correlated with multiple metrics. Key drivers across biological groups included total nitrogen, dissolved oxygen, permanganate index, total phosphorus and electrical conductivity. The findings highlight the joint influence of water quality and hydrology on aquatic biodiversity in natural flow regimes, emphasizing the need for integrated assessments in ecosystem health evaluation.
Miao et al. (Wed,) studied this question.