Spatial assessment of tourists' demand for cultural ecosystem services in the Kalajun World Natural Heritage Site, China

World Natural Heritage Sites encompass extraordinary natural phenomena and aesthetic values and play a prominent role in natural ecological protection and meeting human needs. However, the increased demand for ecotourism in the outer suburbs has caused World Natural Heritage Sites to face degradation risk or even loss of cultural ecosystem service (CES) function. Simultaneously, the academic community's spatial quantification of its CES needs and identification of its relationship with the natural environment remain unclear. Realistic requirements for protecting and developing World Natural Heritage Sites have brought many challenges to planning. Therefore, this study obtained point data related to tourist demand preferences through subjective participatory mapping and social media photos and combined them with the objective MaxEnt model to explore the spatial distribution patterns and contribution rate of tourists to the Kalajan CES demand and environmental variables at the grid scale. Furthermore, a Geodetector tool identified the key driving factors of tourists' CSE demands and the interactions between factors. The findings demonstrate that the aesthetic service experience is always the most favored and widely distributed among tourists. The tourists for high-demand CES areas are mainly concentrated in the south-central part of East Kalajun and along sightseeing vehicles. In addition, the spatial distribution patterns of aesthetics and recreational services are closely related to the vertical three-dimensional landscape of forest, grasslands, and other landforms embedded in the Kalajun tourist area. Elevation, accessibility, and Human footprint (HFP) significantly impact the spatial differentiation of tourist demand, and when combined with elevation and accessibility, the remaining driving factors are significantly enhanced.