[Spatial-temporal Evolution and Prediction of Carbon Reserves in Wanjiang River Basin with the InVEST-PLUS Model]

Abstract

Exploring the impact of space-time-evolution of land use on ecosystem carbon reserves has positive feedback significance for the global emission reduction and foreign exchange increase target. Based on three periods of land use data from 2000 to 2020， combined with the InVEST model， the spatiotemporal changes of carbon storage in Wanjiang River Basin were analyzed. The PLUS model was used to predict the four scenarios of natural development， urban protection， farmland protection， and ecological protection in Wanjiang River Basin in 2040， and the carbon storage of the ecosystem in different scenarios was estimated. The results show that： ① Land use change directly affected the carbon storage of the study area. Between 2000 and 2020， the area of cultivated land， grassland， and unused land decreased by 1 096.73 km²， 5.92 km²， and 4.55 km²， respectively， while the area of forest land， water bodies， and construction land increased by 48.9 km²， 69.68 km²， and 988.6 km²， respectively. The carbon storage decreased by 2.84×10⁶ t， and the distribution of carbon storage was consistent with the spatial distribution of land use. Areas with higher carbon storage had less construction land and more concentrated and distributed ecological land. ②The multi-scenario simulation for 2040 showed that the overall land use pattern was consistent， with significant local changes. In the scenarios of natural development， urban development， and ecological protection， carbon storage decreased by 2.485×10⁶ t， 2.513×10⁶ t， and 0.749×10⁶ t， respectively. Among them， in the scenario of farmland protection， carbon storage decreased by at least 0.029×10⁶ t. ③ The spatial differentiation of carbon storage was mainly influenced by climate factors. The geographic detector indicated that the annual average precipitation （0.139） had the highest explanatory power and was the main driving factor for the spatial differentiation of carbon storage in the Wanjiang River Basin. The synergistic impact type （0.382） between vegetation net primary productivity and annual average precipitation was the strongest. The reduction of carbon reserves can be controlled by adopting the policy of farmland protection and ecological protection. In future planning， ecological land should be protected， and the expansion of construction land should be controlled to improve the level of carbon reserves.

Keywords: Geodetector; InVEST model; Wanjiang River Basin; carbon storage; land use.