Divergent responses of vegetation and soil characteristics to grassland degradation in the Qinghai-Tibet and Inner Mongolia plateaus

Grassland ecosystems are experiencing degradation due to drastic climate change and human activities, yet the impacts on vegetation and soil properties across different grassland ecosystems remain insufficiently explored. This study presented a meta-analysis of 215 publications to investigate how vegetation and soil characteristics respond to degradation in the grasslands of the Qinghai-Tibet Plateau (QTP) and Inner Mongolia Plateau (IMP). Eleven key indicators were selected to evaluate the effects of degradation on these grasslands. The results showed that with degradation intensified, soil bulk density (SBD) and soil pH increased (+16.74%, and +6.08%, respectively), while other soil properties declined. Regarding vegetation features, above-ground biomass (AGB), below-ground biomass (BGB), and vegetation height (VH) generally decreased (−95.85%, −86.94%, and −109.98%, respectively). Notably, reductions in AGB and VH were more pronounced in the IMP than in the QTP, whereas other indicators exhibited stronger responses to the degradation in the QTP. Pearson correlation analysis revealed that both AGB and BGB were significantly positive correlated with soil organic carbon (SOC), soil total nitrogen (STN), and soil water content (SWC). While remarkable negative correlations were found between BGB and pH. Redundancy analysis identified SBD and VH as the most responsive indicators to grassland degradation in both regions. Our findings indicated that degradation severely affected vegetation and soil properties, with regional differences in their responses. This study may provide valuable insights for developing regional management strategies aimed at assessing and restoring degraded grasslands.