Abstract:
The assessment of ecosystem health is a critical foundation for regional ecological restoration and management. Grassland ecosystems, being inherently fragile, have experienced varying degrees of decline in recent years due to the combined impacts of climate change and human activities. This is particularly evident in the Hulunbuir Steppe ecosystem. Among local disturbances, the effect of small rodent activity on grassland ecosystem health has become increasingly prominent compared to other types of disturbances. This study focuses on the typical steppe in Hulunbuir, analysing the impact of Brandt's vole burrow characteristics across different disturbance levels on grassland health. The findings show that variability in health indices and its 4 criterion layer indices is most pronounced at the severe disturbance stage, with the vigor index exhibiting the highest coefficient of variation at 58.09%. There are no significant differences in the vigor and organizational strength indices across disturbance stages. The grassland condition index and health index (CVOR) are significantly higher in un-disturbed and mildly disturbed sites compared to severely disturbed ones, while the recovery index is notably higher in un-disturbed sites than at all other disturbance levels. Burrow density, burrow entrance area, and burrow disturbance index are negatively correlated with grassland condition index, recovery index, and health index, showing significant correlations, however, no significant correlation was found with the vigor index or organizational strength index. As burrow disturbance intensity increased, the grassland health index and its 4 criterion layer indices generally declined, while the vigor index and organizational strength index showed no significant response. Among the indices, the CVOR index exhibited the least variability, showing the highest stability. Compared to burrow density and entrance area, the burrow disturbance index has a stronger correlation with the grassland health index, making it a more comprehensive indicator for assessing the intensity of burrow disturbances in the study of rodent damage to grasslands. The findings of this study provide a scientific basis for evaluating ecosystem health in northern China's grasslands, offering valuable insights for regional grassland managers in implementing effective measures to restore and improve the health of degraded ecosystems.