Evaluation and prediction of ecological environment of Karst World Heritage Sites based on Google Earth Engine : A case study of Libo-Huanjiang Karst

Abstract The results show that: (1) the contribution rate of the four ecological indicators on the first principal component (PC1) is more than 90%. The construction of RSEI based on PC1 is applicable in Karst World Nature Heritage Sites (WNHS) and can be used to monitor and evaluate the spatial and temporal variation characteristics of ecological environment. (2) The mean values of RSEI of Libo-Huanjiang heritage site during 2000, 2007, 2013 and 2020 were 0.5435, 0.5465, 0.6009 and 0.5101, The overall ecological quality is mainly moderate and good, but in the eastern part of the heritage site the ecological quality is poor. (3) The evolution of ecological environment quality during the 20 years is mainly divided into the development trend of rapidly getting better, slowly getting better, and maintaining stability. (4) In the analysis of the relationship between RSEI and altitude, it is found that the ecological environment quality is mainly inferior, less favourable and moderate in areas with altitudes below 600m, and there is a positive relationship between ecological quality level and altitude. (5) By analyzing the ,apparent spatial aggregation between ecological environment quality, and then simulating the ecological grades in 2027 and 2033 using CA-Markov model, it is predicted that the area of medium and excellent ecological grades will increase in the future, but the ecological environment quality still needs to be improved in the eastern region due to the development of tourism industry. Overall, the remote sensing ecological index is an effective model for evaluating and monitoring the ecological environment quality of karst heritage sites; the ecological environment quality of Libo-Huanjiang heritage site is in a steady state of improvement, and the conservation measures of relevant departments are beginning to bear fruit; further coordination between conservation and development is needed to promote the sustainable development of heritage sites and to provide effective solutions for monitoring other karst-like heritage sites.