Quantifying the response of aquatic biodiversity to variations in river hydrology and water quality in a healthy water ecology pilot city, China

Prediction and assessment of the effects of habitat change on aquatic biodiversity remain a hot issue globally. This paper developed a practical methodology based on ecosystem models to comprehensively assess the effects of habitat changes on aquatic biodiversity. The partial least-squares (PLS) method was used to analyse the key hydrological and water quality factors influencing riverine aquatic organisms. The biomass of aquatic organisms under undisturbed conditions was simulated using the food web model Ecosim. Based on the relationship between habitat factors variation and biodiversity variation, a multidimensional river hydrology–water quality–biodiversity response model was established. Application and testing of the methodologies in the first water ecology pilot city in China, namely Jinan City, showed that four water quality factors (total phosphorus, total nitrogen, ammonia nitrogen and dissolved oxygen) significantly affected aquatic biodiversity. For hydrological factors, water depth had a strong effect on fish diversity, whereas flow velocity largely affected fish and algal diversity. The application suggested that response model was practical in modelling the effects of habitat variation on biodiversity. It is anticipated that this model will help assess the effects of changes due to climate- and human-induced stress on aquatic ecosystems and provide a scientific basis for river management decisions.