Land use and landscape patterns strongly influence water quality and are critical for ecological conservation within watersheds, as well as for effective water resource management. This study analyzed water quality data collected from 11 monitoring sites in the Minjiahe Watershed of Qinling Mountains, China. Redundancy analysis was used to analyze the impact mechanism of multi-scale landscape patterns and land use on seasonal water quality changes, while non-parametric change point analysis was used to quantify the key landscape thresholds that lead to sudden changes in water quality. The results indicated that the concentrations of ammonia nitrogen, available phosphorus, and total nitrogen in the river water were significantly higher during the rainy season than during the dry season (p 94%; at the 150 m buffer scale, LSIres < 8 and PLANDfar < 8%. These determined thresholds can be used as indicators for landscape planning to reduce the risk of water quality degradation. The research results provide valuable insights for sustainable land use and multi-scale landscape planning, thereby informing strategies to enhance water quality.
Zheng et al. (Thu,) studied this question.