Qilian Mountain as an important ecological security barrier and water connotation area in China, Research on its vegetation NPP driving mechanism can provide reference for ecological security protection in northwest China. Based on Qilian Mountain MOD17A3 remote sensing data from 2000-2019, using one-dimensional linear regression, partial correlation analysis, multiple linear regression, residual analysis and land transfer matrix. The spatial and temporal dynamics of vegetation NPP in the Qilian Mountain and its correlation with precipitation, temperature and human activities were analyzed, and quantified the effects of climate change and human activities on vegetation NPP. The results show that: 1) from 2000 to 2019 vegetation NPP in Qilian Mountains had an overall fluctuating upward trend and decreased from east to west, with a multi-year average of 138.54 g C·m⁻²·a⁻¹ and an average annual increase of 1.67 g C·m⁻²·a⁻¹; 2) vegetation NPP was positively correlated with precipitation and temperature, with precipitation having a more significant effect on it; 3) the area of grassland in LUCC increased the most and contributed 183.12% to vegetation NPP, while the area of unused land decreased the most and its contribution to vegetation NPP was −119.6%; 4) In the vegetation recovery area, climate change and human activities explained 89% and 11% of the vegetation recovery, respectively. While in the vegetation degradation area, they explained 22% and 78% of the vegetation degradation, respectively.

The Qilian Mountains (QLMs) serve as a vital ecological security barrier in the northwest China, determining the optimal fractional vegetation cover (FVC) of different land-use types is crucial for ecological restoration and protection. Based on the normalized vegetation index, meteorological data, soil data and land-use data, the InVEST model, bivariate spatial autocorrelation and elastic analysis, we calculated the water conservation, soil conservation and carbon storage, analyzed the spatio-temporal distribution characteristics of FVC and ecosystem services (ES) and the correlation between them. This study aims to evaluate the optimal FVC of the different land-use types and vegetation restoration’s effect on it in the QLMs. The results showed that the FVC and ES showed an increasing trend from 2000 to 2020, with a spatial distribution pattern of high values in the southeast and low values in the northwest. There was a significant and positive correlation between FVC and ecosystem service functions (p < 0.05), FVC had the most obvious effect on soil conservation, followed by water conservation. The optimal FVC varied by land-use type, with its value between 0.4 and 0.48 for forest land, 0.24 and 0.30 for grassland and 0.19 to 0.20 for unused land. In the eastern of the QLMs, nearly 70% of the forests and 50% of the grasslands exceeded the optimal vegetation coverage, while 36% of the grasslands and 62% of the unused lands were under-covered in the western of the QLMs. The findings suggest that differentiated ecological restoration and management measures should be formulated according to the status of vegetation restoration, to enhance the comprehensive capacity of ecosystem services in the QLMs.

《地球科学》(ISSN 1000-2383;CN42-1874/P) (原刊名《地球科学——中国地质大学学报》ISSN 1000-2383;CN42-1233/P)，创刊于1957年，是由教育部主管、中国地质大学主办的综合性地学学术理论期刊，月刊，2015年改名为《地球科学》,她以反映中国地质大学教学与科研最新的、高水平的基础地质、应用地质、资源与环境地质及地学工程技术研究成果为主要任务。

Lakes are sensitive indicators of climate change. Based on the lake dataset and Landsat remote sensing data, we analyzed the changes in area and number of lakes(> 1km²) in the Qilian Mountains from 1990 to 2020, as well as the boundary changes of lakes(> 100km²). In addition, we discussed the impact of climate change on lake area. The results showed that: (1) From 1990 to 2020, the total area and total number of lakes in the Qilian Mountains showed an overall increasing trend, with a total area increase of 492.47km² and a total number increase of 10. Among them, Qinghai Lake, Hala Lake, Xiao Qaidam Lake, and Nauru Nor Lake showed an overall expansion trend, while Caka Salt Lake and Da Caidam Lake showed an overall shrinking trend. (2)The main reasons for the expansion of Qinghai Lake and Hala Lake was the increase in precipitation, while the main reason for the expansion of Xiao Qaidam Lake and Nauru Nor Lake was the increase in temperature and precipitation. The main reason for the shrinkage of Caka Salt Lake was the enhancement of evapotranspiration. (3) Lakes in the Qilian Mountains were mainly expanding, which has a good promoting effect on improving the ecological environment of this region and even larger area. However, we should also pay attention to problems such as floods and salt-alkali land caused by lake expansion in a timely manner. In addition, governments and all sectors of society should take corresponding measures to alleviate further shrinkage of Caka Salt Lake.