Grassland phenology dynamics and tourism dependence in Narat Shan of the Tianshan World Natural Heritage Site, China

Grassland phenology plays a critical role in ecosystem functioning and tourism dynamics in natural heritage sites. Focusing on Narat Shan of the Tianshan World Natural Heritage Site, this study integrates multi-source remote sensing, meteorological data, and online behavioral indicators to examine grassland phenology from 2000–2022 and its coupling with tourist visitation. Results show that Grassland phenology strongly drove tourism, with NDVI highly synchronous with tourist numbers. Grassland phenology exhibits clear spatial heterogeneity: SOS advances on northern slopes but is delayed on southern slopes, while EOS generally shows delayed trends, jointly extending the growing season. Elevation and temperature dynamics are the dominant controls, with strong topography–climate interaction effects, whereas human activity plays a minor role. These findings clarify the mechanisms linking climate, phenology, and tourism behavior, providing scientific support for ecological protection and seasonal tourism management in mountain heritage landscapes.