Driving model of land use change on the evolution of carbon stock: a case study of Chongqing, China.

Terrestrialecosystems are significant carbon sinks and are crucial for understanding the regional and global carbon cycles, energy flow, and climate change. As land use change is a significant process affecting ecosystem carbon stocks and striving for land degradation neutrality (LDN), studying it is essential for comprehending the evolution of regional carbon sink functions and achieving sustainable development goals. The drastically diverse land use patterns in each of the study area's regions resulted in significant differences in carbon stock. This study explores the evolution traits of carbon stocks based on land use data and their driving mechanisms in Chongqing during the past 30 years by using spatial analysis, the InVEST model, and geographic probes. The results demonstrate that from 1990 to 2020, land degradation in Chongqing was made worse by the demand for land for construction land, but the strategy of converting cropland back to forests raised the carbon stock of forest land. The overall result is a decrease in total carbon stocks of 5.1078 Tg or 1.5%. The main pathway for carbon loss pathway in the evolution of carbon stock is the conversion of cropland to construction land, and the primary carbon compensation pathway is the conversion of grassland and cropland to forest land, with a spatial distribution characterized by "higher in the whole area and obvious local differences." The land use intensity index has the most significant influence on the evolution of carbon stock. Moreover, the interaction of pairwise factors played a more important role in affecting the evolution of carbon stocks than did each factor individually. The case study in this paper shows that land use change is a significant driving mechanism for the evolution of carbon stock, and the development of a driving model theory is appropriate for deciphering the trajectory of carbon stock evolution and offering research suggestions for other regions.

The coupling effect of socio-economic and eco-environment and land use transformation in mountainous areas-a case of the Fengjie County in the Three Gorges Reservoir Area, China.

Revealing the general laws of land use transformation (LUT) under the coupling evolution of different socio-economic and eco-environment (SE-EE) in mountainous areas is of great significance for rational use of land resources, regional socio-economic development, and eco-environment protection. This paper constructs a research framework of LUT under the coupling evolution of SE-EE and takes Fengjie County as an example to conduct a case study. The results show (1) the socio-economic development level and eco-environment quality showed an overall growth trend from 2000 to 2020, showed the distribution pattern of high in the Yangtze River valley and low in the mountainous areas, and low in the Yangtze River valley and high in the mountainous areas respectively. (2) The coupling evolution of SE-EE showed five types: synchronous development of SE-EE, socio-economic development and ecological retarded, socio-economic retarded and ecological restoration, low socio-economic development level, and low eco-environment quality. (3) The transformation of land use quantity, structure, and function corresponded to the coupling evolution of SE-EE. Cultivated land was reduced when the socio-economic development level was relatively high, and the function changed from production to ecological and eco-economic. When the eco-environment quality was high, cultivated land was reduced, and the function changed from production to ecological. (4) The framework constructed in this paper is universal to the mountainous areas represented by the Three Gorges Reservoir Area (TGRA) and the plain areas where the LUT and SE-EE evolution are different from the mountainous areas.