## 4 Discussion  
### Ecological Quality Changes and Influences in the Study Area  
Based on the GEE platform, this study calculated the RESI to determine the changes in ecological environmental quality in the Qinling region from 1990 to 2020. The results showed that the ecological environmental quality experienced a degradation phase from 1990 to 2005. As depicted in Figure 6, the areas of degradation were mainly concentrated at elevations below 1600 m and slopes less than \(10^{\circ}\), specifically in the administrative regions of Ankang and Shangluo cities. These cities, located in low-elevation valley basins, were areas within the Qinling region where socioeconomic development and urban land expansion were rapid [42]. In this phase, human activities such as extractive mining, urban expansion, and unsustainable cultivation [43; 44] caused a rapid decrease in NDVI in these areas and led to significant environmental damage, resulting in the degradation of ecological environmental quality [17]. The detector results (Table 4) also confirmed that NDVI and land use were the primary factors affecting RESI. As urbanization developed in the study area [42], a significant ecological improvement was observed from 2005 onward, largely due to vegetation conservation initiatives undertaken by the government. Since 2000, the Qinling region has implemented measures such \begin{table}
\begin{tabular}{c c c c c c c c} \hline  & **1990** & **1995** & **2000** & **2005** & **2010** & **2015** & **2020** \\ \hline AIC & 3656.154 & 3419.475 & 4676.3 & 2630.783 & 875.226 & 3301.928 & 1142.899 \\ AICc & 3690.592 & 3426.205 & 4702.93 & 2685.871 & 950.72 & 3404.391 & 1256.355 \\ R\({}^{2}\) & 0.859 & 0.858 & 0.81 & 0.897 & 0.939 & 0.883 & 0.936 \\ adj.R\({}^{2}\) & 0.849 & 0.853 & 0.798 & 0.888 & 0.932 & 0.869 & 0.928 \\ \hline \multirow{4}{*}{Bandwidth} & NDVI & 67.00 & 129.00 & 87.00 & 74.00 & 53.00 & 63.00 & 43.00 \\  & Land use & 183.00 & 1594.00 & 161.00 & 70.00 & 1264.00 & 46.00 & 78.00 \\ \cline{1-1}  & DEM & 371.00 & 309.00 & 309.00 & 286.00 & 351.00 & 70.00 & 71.00 \\ \cline{1-1}  & Protected area & 270.00 & 3609.00 & 303.00 & 149.00 & 60.00 & 362.00 & 195.00 \\ \hline \end{tabular}
\end{table} 
Table 5: Results of multiscale geographically weighted regression. as natural forest conservation and advancing the GFG project [45]. By 2021, the coverage of natural forests in the region had reached 3.56 million hectares, with 840.5 thousand hectares subjected to de-farming [46]. These actions have led to an increase in the vegetation coverage, which in turn has benefited the ecological environment [47]. Notably, areas at higher altitudes saw more rapid improvements, aligning with [PERSON]'s research in the Qilian Mountains [48]. Although variations existed in the ecological environmental quality trends among the different cities within the study area (Figure 6), the overall trajectory for the past 30 years has been positive, reflecting the effectiveness of the ecological restoration efforts undertaken. This study employed geodetector to reveal the factors influencing ecological environmental quality in the area. NDVI emerged as the principal factor, exerting the greatest impact on the ecological environmental quality of the study area, followed by temperature, which is consistent with the findings of [PERSON]'s research in the upper Yellow River basin [49]. This is because surface vegetation cover proves to be a crucial regulator of surface moisture, energy exchange, and ecosystem balance, effectively curtailing environmental challenges like soil erosion [50]. As a contributing factor, an increase in temperature can lead to soil desiccation, subsequently impacting ecological environmental quality by altering vegetation growth patterns [51; 52]. The ecological environment is influenced by both natural factors and human activities, with the latter still playing a dominant role [53]. In the Qinling region, ecological quality positively correlates with the intensity of management, and inversely with human disturbance.