## 4 Discussion
### Spatial Patterns and Effects of ECIs on Ecosystem Resilience  
For the first time, we combined CECIs with individual ECIs to study their impact on EIs. Our analysis indicates that the CECIs primarily affect the NDVI, but their significance is relatively low. In the HDMs, temperature variation and low temperatures were the main limiting factors, exerting a continuous impact on EIs, particularly in high-altitude areas [38; 44]. The HDMs are characterized by high elevation, a sparse population, and proximity to the Qinghai-Tibet Plateau, resulting in human activity having a minimal impact on vegetation growth. In the YGP, vegetation growth generally benefited from extreme climate events, with only freezing and low-temperature indices having sustained negative effects on EIs. Future extreme climate events, particularly extremely high temperatures, may further promote vegetation growth in this region [45]. Moderate warming can enhance plant respiration and photosynthetic activity, allowing vegetation to have positive responses to temperature changes [44].  
The GXB demonstrated resilience to extreme climate events. Extreme high temperatures slightly promoted vegetation growth during non-summer periods; however, during the summer, prolonged droughts inhibit the GPP, and extreme high temperatures also suppress the NDVI. In the SCB, vegetation productivity shows no significant response to extreme climate events. Random forest regression results indicate that the GPP in the SCB shows a weak response to the ECIs, although the NDVI shows a more notable response. This discrepancy could stem from differences in the functional roles and sensitivities of the NDVI and GPP: the NDVI primarily reflects vegetation greenness and canopy structure, which respond more immediately to temperature extremes, whereas the GPP, as a measure of carbon assimilation, is moderated by factors such as water availability and photosynthetic efficiency. Additionally, the agricultural dominance in the SCB (Figure 1) may reduce the fluctuations in the GPP due to irrigation practices, while the NDVI remains more vulnerable to heatwaves. The NDVI is significantly negatively correlated with extreme temperature indices at various time scales, while low temperatures can continuously promote vegetation growth (Figure 4f). The impacts of climate change and human activities on vegetation growth are dual in nature [46]. In the SCB and GXB, where crops are predominant, human activities play a crucial role in influencing vegetation productivity. Practices such as natural forest conservation, reforestation projects, and agricultural management contribute to stabilizing vegetation dynamics. For instance, reforestation efforts under initiatives like the 'Grain for Green' program have enhanced forest cover and improved soil quality, which indirectly improves vegetation's resilience to climate extremes [47]. However, in the GXB, despite its vulnerability to summer extreme climates like prolonged droughts and heat-waves, adaptive agricultural practices, including irrigation systems and drought-tolerant crop varieties, mitigate adverse effects and enhance overall adaptability [48]. This dual influence of human activities and climatic factors underscores the complex interactions that drive vegetation productivity in these regions.  
The vulnerability and resilience of different ecosystems to extreme climate events may influence their interrelationships [49]. Interactions between climate variables, such as the potential for extreme high temperatures that may increase the likelihood of extreme precipitation, are also critical factors [44]. Our study demonstrates significant differences in EIs and extreme climate interactions across various geographical environments within the same study area. Therefore, it is crucial to consider the unique characteristics of different regions when developing strategies to cope with extreme climate events in the future.