Amphibian diversity and its elevational pattern in Wawu Mountain National Forest Park

The spatial distribution pattern and driving factors of species diversity are hot topics in conservation biology research in recent years. Amphibians, as the most threatened vertebrate group, urgently need effective protection and continuous monitoring. Wawushan National Forest Park is located in the transitional zone between Hengduan Mountain and Sichuan Basin, with diverse habitat types and rich biodiversity, and has a very unique position in biodiversity conservation of southwest mountain areas in China. In order to promptly update the amphibian species list in the area, and explore the elevational patterns of species diversity and the key influencing factors, based on the existing historical data, 62 transects were set up in four representative areas of the park (Mount Wawu, Mount Yuping, Zhangcun, Tongchangba) from 2023 to 2024, and the survey of amphibian diversity and elevation distribution was systematically carried out. By integrating field survey and historical data, the study revealed rich diversity and high endemism of amphibian in Wawushan National Forest Park. There were 36 species belonging to two orders, nine families, and 19 genera. Among which, 14 species were endemic to China, accounting for 38.89% of the total number of species, eight species (22.22%) were endemic to Sichuan Province, and three species (8.33%) were endemic to Hongya County. The overall G-F index of amphibians in the park is 0.326. In terms of habitat types, natural forests exhibited the highest G-F index (0.102), and planted forests and farmlands displayed relatively lower indices (−0.260; −0.591). At the geographical region level, the species were mainly from the Oriental realm and Southwest realm; at the ecological types level, terrestrial-stream species were the majority. The recorded amphibians were primarily distributed at elevations of 400–2,704 m, with 25% of species vertically distributing less than 200 m. The elevational pattern of amphibian species diversity in Wawushan National Forest Park showed a unimodal distribution pattern, with total species richness peaking at an elevation of 1,200 m and threatened species richness peaking at 1,600 m. The annual mean temperature, annual precipitation, and normalized difference vegetation index collectively drove the elevational pattern of amphibian diversity in Wawushan National Forest Park, and the annual mean temperature was significantly positively correlated with amphibian diversity along the elevational gradient. This study illuminated the elevational pattern of amphibian diversity in Wawushan National Forest Park, as well as the underlying factors driving this distribution. The findings provided essential data to inform future research in conservation biology.