# Water Use Efficiency Spatiotemporal Change and Its Driving Analysis on the Mongolian Plateau
## 5 Conclusions  
In this study, we used a variety of statistical methods to analyze the temporal and spatial dynamic changes in NPP, ET, WUE, and DSI on the Mongolian Plateau from 1982 to 2018 and evaluated the response of WUE to changes in meteorological factors, vegetation, and human intervention.  
The following are the main conclusions of our work.  
1. The annual average NPP and WUE were 232.75 gC/m\({}^{2}\cdot\)year and 0.592 gC/mm\(\cdot\)m\({}^{2}\cdot\)year, respectively. Over 37 years, the annual WUE decreased significantly, while the annual ET increased. Significant WUE decreases were observed in Central and Eastern Mongolia and in broadleaved forests in Northeastern Inner Mongolia. Significant increases were found in Central and Southern Inner Mongolia. Two WUE\({}_{\text{Season}}\) surges were detected in 1997-1998 and 2007-2009. Some broadleaf forests in Inner Mongolia reversed their decreasing WUE trends in winter. The overall trend suggests that the WUE may shift from decreasing to increasing in the future. The Mongolian Plateau showed strong WUE resilience, except for artificial vegetation areas in Central Inner Mongolia.
2. WUE was significantly affected by precipitation and soil moisture, showing resistance to anomalous water disturbances. It had a weak correlation with the temperature and limited resistance to temperature disturbances. WUE was positively correlated with the DSI, although its resistance to DSI anomalies was weak.
3. Vegetation change had a stronger impact on WUE than meteorological factors. WUE showed weak resistance to anomalous NDVI disturbances. Delayed rejuvenation positively influenced WUE. Interactions between phenological parameters and meteorological factors enhanced WUE nonlinearly. Human activities significantly contributed to WUE increases in Eastern, Central, and Southern Inner Mongolia.  
**Supplementary Materials:** The following supporting information can be downloaded at: [[https://www.mdpi.com/article/10.3390/s25072214/s1](https://www.mdpi.com/article/10.3390/s25072214/s1)]([https://www.mdpi.com/article/10.3390/s25072214/s1](https://www.mdpi.com/article/10.3390/s25072214/s1)).
* [PERSON] analyzed the data and wrote the paper. [PERSON] conceived and designed the experiments. [PERSON]. ([PERSON]), [PERSON], M.Y., [PERSON], [PERSON] and [PERSON]. ([PERSON]) revised the manuscript. All authors have read and agreed to the published version of the manuscript.
* This paper was supported by the National Natural Science Foundation of China Regional Project (Grant No. 42467065), the Inner Mongolia Autonomous Region Philosophy and Social Sciences Planning Project (Grant No. 2022 NDA225), the Major Science and Technology Program of Inner Mongolia Autonomous Region (Grant No. 2021 ZD004503), and the Inner Mongolia Autonomous Region Key Research and Achievement Transformation Program (Grant No. 2022 YFB0070).
* Not applicable.
* Data available on demand.  
**Acknowledgments:** We would like to thank the anonymous reviewers for their valuable comments and guidance, which greatly improved the manuscript.  
**Conflicts of Interest:** The authors declare that they have no known competitive financial interests or personal relationships that may affect the work reported herein.