Analysis of the factors causing degradation and changes in the colourful pool area of the Huanglong travertine in Sichuan Province, China

Travertine is the most important karst rock in the Huanglong Natural Scenic Area in China. This rock not only has ornamental value but also has scientific research significance. This study used four high-resolution images of the Huanglong Ravine from different periods to record the spatial evolution of climate, vegetation, and tourist activities from 2000 to 2022 and combined unmanned aerial vehicle orthophotos with high-resolution images to analyse the main reasons for the extension and change in the Huanglong Ravine colourful pool area from 2004 to 2020. The results showed that during the period from 2000 to 2022, the atmospheric precipitation in the Huanglong Scenic Area increased from 733 mm to 926 mm, the vegetation coverage increased from 95.76 to 96.92