**5. Conclusions**

We investigated NDVI and GPP in the growing season and changes in the spatiotemporal variation patterns of their centers of gravity in southwest China from 2000 to 2019. We found that the LULC structure of the study area changed greatly from 2000 to 2019. The area of forest increased while the area of cropland and grassland decreased, and cropland was the main contributor to the forest increase. For the entire study region, both NDVI and GPP in the growing season showed a generally increasing trend. However, there were differences in the increasing trend of NDVI and GPP among different LULC types. From the perspective of spatial distribution, NDVI and GPP showed a distribution pattern of high in the southeast and low in the northwest, corresponding to the fact that forest is mainly distributed in the southeast and grassland is concentrated in the northwest; the ecological restoration project has greatly improved the vegetation coverage, 45.6% of the region showed a greening trend. In 2000, it was dominated by medium coverage and high coverage (32.32%, 54.73%), while high coverage and highest coverage predominated in 2019 (49.29%, 34.37%). Under the same vegetation coverage, the spatiotemporal variation distribution of the center of gravity of NDVI and GPP was basically the same. From 2000 to 2019, the spatial variation in the center of gravity of NDVI and GPP at the lowest coverage was relatively stable; the center of gravity of low coverage shifted to the east, the center of gravity of medium coverage and the high coverage both shifted to the northwest, and the center of gravity of the highest coverage moved to the southeast. This indicates that although the southwest region is greening, there are differences in vegetation growth and carbon sequestration capacity among different land cover types, resulting in changes in the vegetation center of gravity. Therefore, the combination structure of vegetation cover and land cover type should be prioritized in the future to ensure the balance of the ecosystem in the southwest and maintain sustainable development.

**Author Contributions:** Conceptualization, L.R. and X.L.; methodology, X.L.; software, M.Z. and C.Y.; formal analysis, X.L. and W.Y.; investigation, M.Z., Q.W., Z.Z., and C.Y.; data curation, X.L.; writing—original draft preparation, X.L.; writing—review and editing, L.R. and X.L.; visualization, X.L.; supervision, X.L.; project administration, X.L.; funding acquisition, L.R. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research was funded by the key project of the "14th Five-Year" National Key R&D Program "Typical Fragile Ecosystem Protection and Restoration", grant number "2022YFC080900" and the Karst plateau canyon rocky desertification comprehensive control and scale management technology and demonstration of ecological industry, grant number "2016YFC0502603", Project of National "Thirteenth Five-year" Key Research and Development Programme.

**Institutional Review Board Statement:** Not applicable.

**Informed Consent Statement:** Informed consent was obtained from all subjects involved in the study.

**Data Availability Statement:** Not applicable.

**Acknowledgments:** We thank the anonymous reviewers for their valuable comments. We gratefully acknowledge the design of L.R. and the contribution of co-authors.

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

#### **Appendix A**

**Table A1.** Transformation matrix of NDVI grades from 2000 to 2019 (km2).


**Figure A1.** Variation in the center of gravity of different NDVI grades and its GPP. (Note: (**a**–**e**): Changes in the center of gravity of the five NDVI grades from 2000 to 2019; (**f**–**j**): Changes in the center of gravity of GPP for five NDVI grades from 2000 to 2019).
