## 4 Discussion  
### Spatial Heterogeneity of NCPs on the QTP  
NCPs emphasize a more comprehensive approach by incorporating regulating, material, and non-material values, offering a broader perspective compared to traditional ecosystem services (ES) frameworks, which predominantly focus on human-centered benefits [7]. This holistic view was particularly significant for the Tibetan Plateau (QTP), where the unique ecosystem and landscape necessitated integrated management strategies. Previous studies explored the spatial distribution of ES in the QTP, revealing higher carbon sequestration, water yield, and soil conservation in the southeastern region and lower values in the northwest. Additionally, habitat quality was found to be highest in the southern QTP [37, 38]. In contrast, our study found notable differences in the spatial distribution of habitat quality and water yield when compared to NCP1 and NCP6. These discrepancies can be attributed to variations in the assessment methods and indices employed, leading to differing trends between NCPs and conventional ES.  
When assessing NCP1, we used the mean species abundance (MSA) as a biodiversity index, which showed a distinct spatial pattern, i.e., MSA was higher in the western QTP and lower in the eastern part. Previous studies primarily focused on habitat quality and species richness to assess biodiversity [39], but our findings emphasized species richness, revealing significant variations due to human influence and climate change. These changes notably reduced MSA in the eastern QTP. Despite this, the eastern QTP still supported higher species abundance than the west, owing to more favorable conditions, such as lush forests, grasslands, and greater precipitation, which promoted biodiversity [16].  
Additionally, we used the Water Supply Index (WSI) based on multiple factors, including precipitation, snow, glaciers, and lakes, which yielded a spatial distribution pattern that differed slightly from earlier research that focused mainly on precipitation and potential evapotranspiration [40]. Our study further highlighted the spatial mismatch between potential water supply and actual demand, which previous studies had not fully addressed. The contribution from water supply was significantly higher in the southwestern QTP, where glaciers and lakes provided abundant water resources. However, our findings also indicated that actual water demand was higher in the eastern QTP due to its larger population and greater domestic, agricultural, and industrial water needs [41]. This discrepancy  
Figure 8: Hierarchical ecological priority areas based on the importance and vulnerability of NCPs. (**(a–c)** represent the pixel scale; **(d–f)** represent the water tower unit scale).  
underscored the imbalance between Nature's Contributions to People (NCPs) and actual demand in different regions of the QTP. By quantifying spatial differences in NCPs from both supply and demand perspectives, our study offered a more nuanced understanding of the region's ecological imbalances and highlighted areas where conservation efforts should be prioritized to bridge the gap between available resources and demand [42].