## 4 Discussion
### The Impact of Drought on Vegetation Loss  
Many studies in the field of drought impact on vegetation have provided compelling evidence for the critical relationship between vegetation loss and drought in the context of climate change [72; 73; 74]. Generally, the impact of drought on vegetation varies with drought severity, wherein more severe drought conditions result in greater vegetation loss [75]. Our results showed that the vegetation dynamics under different drought intensities, whether during the more severe drought in 2012 or the relatively milder drought in 2019, exhibited minor variations in regions affected by drought and severe drought during 2011-2013 and 2018-2020 (Figure 5). However, in mild drought regions experiencing drought years (2012 and 2019), the vegetation exhibited a significant decline compared to the vegetation before and after the drought years (2011, 2013, 2018, and 2020) (Figure 5c). On the other hand, the vegetation in the normal and moist regions showed similar patterns to that in the drought-affected regions, with relatively small changes during both the drought years and the periods before and after the drought (Figure 5d,e,i,j).  
In a previous study using SPEI to investigate the impact of drought on vegetation loss, it was found that vegetation loss was more sensitive to the duration of drought than to its severity and peak intensity and that there was no clear linear relationship between drought intensity and the degree of vegetation loss [76]. This finding is consistent with our results. This was because vegetation that has evolved to grow in arid environments for many years has developed strong adaptability to drought stress [77]. Plants in this region typically possess water-preserving mechanisms to counteract drought [78]. Moist regions typically receive more precipitation and have abundant water resources, which can satisfy the water requirements for vegetation growth and reproduction even during periods of drought [79]. This abundance of water resources mitigates the direct impact of drought on vegetation [80]. The humid climatic conditions in these regions endow the vegetation with greater growth potential and productivity, characterized by robust root systems and dense foliage [81; 82]. Additionally, such regions tend to exhibit greater biodiversity and ecosystem complexity [83].  
In comparison with our study, research utilizing SPEI similarly provides valuable insights into drought impacts. SPEI, which integrates variations in precipitation and evapotranspiration, is effective in accurately assessing drought effects on vegetation. Studies by [PERSON] and [PERSON], using SPEI to analyze vegetation vulnerability in Central Asia and Xinjiang, showed that areas with lower SPEI values generally experienced greater vegetation loss, whereas more humid regions were less affected [19; 84]. This finding aligns with our results, which indicate that the drought of 2012 had a significant impact on vegetation, while the relatively mild drought of 2019 resulted in less vegetation loss. SPEI analysis further supports the view that vegetation recovery is stronger in humid regions due to abundant water resources and favorable climatic conditions that facilitate recovery [85]. Different vegetation species may complement each other, with some demonstrating resilience under drought stress and others maintaining healthy growth to sustain ecosystem stability [86; 87]. In addition, regions with relatively humid environments are also suitable for human habitation, and the additional water supplied by humans during vegetation drought is a significant factor in preventing vegetation loss [88].