**5. Conclusions**

This study employed remote sensing data and macro-scale hydrological modeling, and determined the role of past LCC in reshaping the future hydrological regime across the TNR of China. Land cover change may have imposed minor impacts on the hydrological regime over the past three decades. In contrast, it was found in this study that LCC may play a more significant role in altering ET and R in the future. The conclusions are as follows:


(4) Land cover changes in the TNR will play different roles in influencing ET and R. Specifically, LCC will likely slow the rate of increasing ET, while promoting increases in R, although the strength of these effects will vary across different basins. In the SRB, LRB, and HRB, the effects are much stronger than in other basins, and in the eastern four basins, R and SM will increase due to LCC, while decrease in the IRB. Additionally, the effects of LCC on ET, R, and SM will all increase over time, which means that the effects of LCC will increasingly strengthen in the future.

Compared to the hydrological effects over the past decades, the strengthening role of LCC on the future hydrological regime can be attributed to its long-term, cumulative effects and strengthening climate change (i.e., the rising temperature and increasing precipitation). However, the future hydrological regime in the TNR will be primarily driven by climate change. Based on the SM, the arid region (i.e., the IRB) may become drier and the humid regions (i.e., the east of the YRB and the south of the HRB) may become wetter, and these effects are consistent with the standard catchphrase, "dry gets drier, wet gets wetter" [39–41]. LCC may likely intensify these effects, implying dryland expansion in arid and semi-arid areas and a potentially increased flood risk in humid areas, although it may diminish ET so as to preserve water resources. Uncertainties may exist in our study, including the interactions among climate, water, and vegetation. Coupling land use and vegetation dynamics in the hydrological modeling can improve future hydrological projections.

**Author Contributions:** Conceptualization, Y.Y. and X.X.; methodology, Y.Y.; validation, X.X.; formal analysis, Y.Y.; investigation, Y.Y.; resources, Y.Y.; data curation, Y.Y., X.X., S.M., B.Z., K.Z. and Y.W.; writing—original draft preparation, Y.Y.; writing—review and editing, X.X.; visualization, Y.Y.; supervision, X.X.; project administration, X.X.; funding acquisition, X.X.

**Funding:** This research was funded by the National Natural Science Foundation of China (No. 41471019, 61661136006) and the National Key Research and Development Program of China (No. 2016YFC0401404). And The APC was funded by the National Natural Science Foundation of China (No. 41471019).

**Acknowledgments:** We would like to thank the three anonymous reviewers for their constructive comments and language editing.

**Conflicts of Interest:** The authors declare no conflict of interest.
