Comparative impacts of climate change and human activities on spatiotemporal changes of bare land in the Turpan-Hami...

Desertification in arid regions poses significant threats to ecological security, necessitating detailed investigations into its spatiotemporal dynamics and driving mechanisms. This study examines the evolution of bare land in the Turpan-Hami Basin from 1985 to 2020 using land use/cover data, integrated with climatic variables (potential evapotranspiration, wetness index), human footprint indices, and soil organic carbon (SOC) content. Our results revealed that (1) from 1985 to 2020, bare land area decreased by 16,251 km² (- 6.4%), with notable regional heterogeneity: reductions occurred in the northern (NB) and southern basins (SB) (8.06-8.23% of change rates), while the Tianshan Mountains (TM) experienced a 28.50% increase; (2) 81.04% of bare land transitioned to grassland, followed by shrubland (13.78%), with shrubland conversion accelerating post-2000 (peaking at 14.09%). (3) Climate change affected the trend for bare land, whereas human activities exhibited divergent impacts which was intensifying bare land expansion in NB and TM through overgrazing, but suppressing expansion in SB through oasis reclamation. Moreover, the soil organic carbon influenced bare land stability, though its effects were modulated by climate-human interactions. This study demonstrates the synergistic interactions between climate change and human activities in driving bare land dynamics. Future desertification management requires region-specific strategies that integrate climate change projections.