Abstract: Assessing the spatiotemporal evolution of the ecosystem service values (ESV) in typical tourist cities plays a crucial role in formulating policies for urban conservation and environmental management. However, there is still a dearth of research on the spatiotemporal changes and spatial transfer networks of ESV in Guilin, Guangxi. With the six urban districts of Guilin, Guangxi Zhuang Autonomous Region, as the study area, this research employs equivalent factor correction and grid analysis methods to analyze the spatiotemporal changes in ESV based on land-use data spanning from 2000 to 2020. Leveraging the ecological service value equivalent factor table for Guilin, the breakpoint model and field strength model for ecological value transfer are applied to quantify the ESV transfer within the six districts, and visualize the spatial transfer network. The results indicated: (1) From 2000 to 2020, the total ESV in the six districts of Guilin showed a downward trend, decreasing from 2,866,942,700 yuan to 2,836,185,100 yuan. During the study period, each individual ESV component in these districts decreased over time, with the regulating services experiencing the most significant change. This suggested that urban expansion and land-use changes accompanying tourism development have had adverse impacts on ESV. (2) Among ecosystem service functions, climate regulation and hydrological regulation account for the largest proportions. The ranking of secondary ESV was: climate regulation > hydrological regulation > soil conservation > nutrient cycling maintenance > gas regulation > biodiversity > environmental purification > aesthetic landscape > food production > raw material production > water supply. The significant contribution of climate regulation is attributed to the vast forest area in Guilin, which played a pivotal role in regulating the climate. Climate and hydrological regulation were indispensible components of ecosystem services, essential for maintaining climatic stability, ensuring water supply, and mitigating natural disasters. (3) At a 1 km × 1 km grid scale, there were notable differences in the spatial distribution of ESV in Guilin. From 2000 to 2020, the area of high-ESV regions decreased over time, while the low-ESV regions were primarily concentrated in the northern part of Xiangshan District, the western part of Xiufeng District, the eastern part of Qixing District, and the southwest of Diecai District. Meanwhile, the area of regions with relatively high ESV increased over time, with Linggui District experiencing the most significant increase. This may be linked to urban development and construction, especially the "county-to-district" administrative reformation in Linggui. (4) The outward transfer of ESV among districts within the study area was ranked from largest to smallest as: Linggui District > Yanshan District > Diecai District > Xiufeng District > Xiangshan District > Qixing District. Hydrological regulation represented the service function with the highest transfer volume, accounting for 18.78% of the total ESV transfer in the study area. Regions with higher ESV tended to transfer more ESV externally. This study explores the status of ESV in the six urban districts of Guilin, Guangxi over a 20-year period and reveals the spatial transfer relationships among districts. It provides valuable insights into the spatiotemporal evolution of ESV in these districts, serving as a reference for future urban ecological protection, regional environmental management, and sustainable resource development.

Key words: ecosystem services values, spatio-temporal evolution, spatial transfer, breaking point model, field intensity model, Guilin, China