## 3 Results
### Established Protected Areas Contributed to Forest Ecosystem Protection Efforts  
Using spatial sampling and the propensity score matching (PSM) method, we analyzed forest and grassland loss to assess the effectiveness of existing protected areas in the Altai Mountains National Park Candidate Area. The results show that the estimated average forest restoration area in protected areas was 1168.68 m\({}^{2}\) higher than in similar unprotected areas, while the average grassland loss area in protected areas was 3007.42 m\({}^{2}\) higher than in similar unprotected areas (\(p<\) 0.01, Table S2). These findings suggest that the established protected areas have the potential to reduce forest loss and increase grassland loss by approximately 31.64% and 16.28%, respectively. The Altai Mountains National Park Candidate Area contains eight protected areas (Figure S5), with considerable variation in effectiveness between them (Figure 9b). Xinjiang Habahe Akeqi National Wetland Park demonstrated the best effect in curbing forest loss, while Xinjiang Burqin Kanas Lake National GeoPark performed the best in reducing grassland loss. Conservation efforts in existing protected areas have primarily focused on forests, often neglecting grasslands. Figure 9a illustrates the difference in forest and grassland loss between protected and unprotected areas from 2000 to 2020. This indicates that the protected areas significantly reduced forest loss in 2005 and grassland loss in 2012-2013, but were generally less effective in limiting grassland loss. The differences in forest and grassland loss across different protected areas (Figure 10) reflect the variation in the impact of management initiatives. Kanas, Baihaba, Jiadengyu, and Kanas GeoPark exhibit similar tendencies in preventing the loss of both forests and grasslands. However, Baihaba  
Figure 8: The interaction results of ecosystem changes in the Altai Mountains National Park Candidate Area: (**a**) forest ecosystem and (**b**) grassland ecosystem. (\(\times\)1: elevation, \(\times\)2: slope, \(\times\)3: average annual temperature trends, \(\times\)4: average annual precipitation trends, \(\times\)5: SPI trends, \(\times\)6: GPP trends, \(\times\)7: soil type, \(\times\)8: grazing intensity trends, \(\times\)9: cropland trends, \(\times\)10: population distribution trends, \(\times\)11: distribution of tourist attractions, \(\times\)12: distribution of mining sites). exhibited distinct manifestations in 2005, effectively curbing grassland loss but being less efficacious in reducing forest loss. Keketuohai was less efficient in curbing the loss of both forests and grasslands. Habahe and Akeqi performed optimally in forest protection in 2006 and 2007, and 2005 and 2008, respectively. Burqin effectively mitigated grassland loss in 2004, 2013, and 2019. The effectiveness of different protected areas in reducing forest and grassland loss varies over time, potentially due to differences in their management strategies and environmental characteristics. Furthermore, all protected areas exhibit fluctuating disparities in the loss of forests and grasslands, highlighting the necessity of continuous and adaptive management to guarantee the success of long-term conservation. Existing protected areas have made positive contributions to the main conservation objectives, demonstrating the success of conservation efforts in the region, especially for forest ecosystems. Kanas GeoPark and Jiadengyu have been the most effective in forest conservation and serve as valuable examples of in situ conservation for future national park development. However, the variability in effectiveness suggests a need for more comprehensive management strategies that equally address both forest and grassland conservation. Specific management practices could include integrated habitat management, enhanced monitoring of both ecosystems, and adaptive management approaches that tailor conservation actions to the needs of each ecosystem.