Explaining variations in the stability of the ecosystem of the largest fresh lake in China from 2013 to 2023

Poyang Lake is the largest freshwater lake in China. In recent years, the stability of the lake's ecosystem has been challenged by climate change and human activities. It is important to study changes in the lake to understand how to maintain the health of the lake ecosystem. To date, individual factors have been used to support studies of the lake's stability. However, these studies are inadequate because they fail to provide quantitative information for multiple factors. In this study, we innovatively proposed a method for quantifying the lake stability that considered multiple habitat and biotic factors, thereby advancing our understanding of the drivers influencing changes in lake stability. We analyzed monitoring data from Poyang Lake for long-term changes in the stability and used structural equation modeling to quantitatively assess the main influences on the lake stability. Our results showed that the ecosystem stability index of Poyang Lake decreased by 12.3 % from 2013 to 2023, which indicates that the stability of the lake gradually declined. We further found that zooplankton, phytoplankton, and ammonium nitrogen were the main causes of the decline in the lake stability. The method utilized in this study can assist lake managers in analyzing the effects of environmental changes on lake stability, facilitate the rapid identification of key factors influencing stability variations, and provide a scientific basis for assessing the ecological health of lake waters.