The transboundary influence of environmental change is a critical issue in the Lancang-Mekong region.As the largest river-connected lake in the lower Mekong,the ecological change and influence of Tonle Sap Lake have received widespread attention and discussion,especially after 2008,when the hydrological regime of the Lancang-Mekong River mainstream underwent distinct changes.However,the linkage and coupling mechanism between the lake riparian environment and mainstream water level change are still unclear.In this study,the interannual spatiotemporal changes in land cover in the Tonle Sap Lake riparian zone(TSLRZ)and their relationship with mainstream water levels were analysed.The results showed that the expansion of farmland was the most notable change in 1988–2020.After 2008,the land cover changes intensified,manifested as accelerated farmland expansion,intensified woodland fragmentation and significant water body shrinkage.Furthermore,the responses of the water body,degraded land,wasteland and grassland areas to the mainstream water levels weakened after 2008.Evidently,the land cover changes in the TSLRZ in the last 30 years were less related to the mainstream water level change than to local reclamation and logging.These results can offer a new scientific basis for the transboundary influence analysis of hydrological change.
