## 4 Discussion
### Insights from Geodetector Analysis on Drivers of Ecosystem Change  
Previous studies have primarily analyzed the drivers of ecosystem change either at an aggregate level or within individual ecosystems [78; 79]. In contrast, our study separately examines the drivers of two key ecosystems--forest and grassland--offering insights that can inform the development of targeted management strategies. Forest and grassland dynamics are driven by a range of complex factors. Earlier studies on the drivers of ecosystem change largely focused on the combined effects of climate change and human activities [76]. These studies often neglected the independent and interactive influences of specific environmental factors and anthropogenic disturbances. Our analysis, using Geodetector, reveals that soil type and elevation are primary drivers of forest dynamics, aligning with the findings of [PERSON] et al. [80] and [PERSON] and [PERSON] [81]. Numerous studies have shown that forests are sensitive to changes in elevation, soil nutrient gradients, and soil CO2 emissions, all of which influence forest dynamics in this region [82; 83]. The natural altitudinal zones shape the diverse landscapes of the region, such as the Europe-Siberian taiga forest and the north forest steppe, among others [26]. Altitude plays a significant role in shaping hydrothermal conditions, which, in turn, affect vegetation growth by regulating air temperature and modulating the impact of climate change on plant development [84]. Additionally, precipitation and anthropogenic factors play crucial roles in determining the altitudinal gradient of vegetation [85]. These varying elevations correspond to distinct soil types (Figure S4). Studies have documented variability in soil moisture content across different ecosystems in Xinjiang [86], and have established a bidirectional causal relationship between soil moisture and vegetation productivity [87]. These findings underscore the importance of soil and water conservation in promoting forest growth. Implementing effective conservation measures can reduce soil erosion, enhance soil fertility, and create stable conditions favorable for forest expansion. Cropland change emerged as the primary driver of grassland dynamics, corroborating the findings of [PERSON] et al. [79]. The conversion of grassland to cropland leads to changes in soil quality, a reduction in native vegetation, and increased land degradation, all of which significantly impact grassland ecosystems. Coupled with the ecosystem transfer chord diagram, this suggests that cropland expansion [88] and China's Grain to Green Program [89] have jointly influenced grassland ecosystems. Our study also demonstrates that the combined effects of cropland expansion and desertification significantly contribute to grassland degradation [12; 90]. Such degradation compromises the ecological functions of grasslands, adversely impacts biodiversity, exacerbates ecosystem vulnerability, and poses substantial threats to the sustainable development of these regions [91]. Therefore, implementing effective desertification control and grassland restoration strategies is crucial for maintaining the ecological integrity of grassland ecosystems. The results (Figures 7 and 8) also highlight the significant impact of human activities. The Altai Mountains are an ecologically sensitive region, but they also have significant economic value due to agriculture, tourism, and resource extraction. Balancing ecological preservation with the socioeconomic and cultural dimensions of the Altai Mountains poses significant challenges. Human activities--such as cropland expansion, grazing, tourism, and mining--exert complex pressures on forest and grassland ecosystems [92]. Given the region's ecological sensitivity and economic importance, conservation strategies must acknowledge the challenges of balancing ecological preservation with local livelihoods, tourism development, and cultural values.