Analysis of factors influencing the ecologically suitable areas for Glyptosternum maculatum in the Yarlung Zangbo River

Glyptosternum maculatum, predominantly found in the middle and upper reaches of the Yarlung Zangbo River (YR) and its tributaries, is a fish species accorded second-class national protection. In 2021, it was recognized as one of the top ten excellent aquatic germplasm resources in China. However, its living conditions are far from promising. Therefore, in this study, we used the MaxEnt model to simulate potentially suitable habitat for G. maculatum, and then reconstructed the ecologically suitable habitat for G. maculatum using the kernel density algorithm after taking into account the distribution characteristics of hydropower stations. We predicted changes in area of the ecologically suitable habitat for G. maculatum under future climate change scenarios. The results indicate that the primary ecologically suitable areas for G. maculatum are situated in Ngamring County, Saga County, and Mainling County, covering a total area of 553.15 km2. Flow accumulation, NDVI, and the seasonality of temperature change are the main environmental factors affecting the distribution of G. maculatum. In the future, considering the ongoing impacts of factors such as hydropower stations and climate conditions, the projected suitable habitat area for G. maculatum is expected to span between 433.90 and 516.23 km2, marking a forecasted decrease of approximately 6.68 to 21.56 %. To prevent further reduction of suitable habitat, protective measures should be taken as early as possible.