[Analysis of Spatial-temporal Variation and Driving Forces of Carbon Storage in Suzhou City Based on the PLUS-InVEST-Geodetector Model].

Abstract

The changes in urban land use and land cover have profound impacts on carbon storage, directly affecting urban carbon balance and climate adaptation capacity. Taking Suzhou City as the study area, this study first conducts a transition matrix analysis of land use data from 2000 to 2020. Then, based on the modified carbon density coefficient coupled with the PLUS and InVEST models, predictions are made for the land use pattern of Suzhou City in 2030 under four scenarios （business-as-usual development, urban sprawl prevention, farmland protection, and ecological conservation）. The ecosystem carbon storage from 2000 to 2020 and in 2030 under the four scenarios in Suzhou City are accounted for and the impact of land cover changes on carbon storage is analyzed. Finally, the Geodetector model is used to analyze the spatial differentiation driving forces of carbon storage. This study explores the mechanisms of land use change on carbon storage in regions with high urbanization levels. The results are as follows： ① From 2000 to 2020, Suzhou City's land use pattern underwent significant changes, with a continuous reduction in farmland and woodland, and the conversion of farmland to construction land was especially prominent. ② From 2000 to 2020, Suzhou City lost 3 750 195.27 t of carbon storage. Farmland and water bodies were the main carbon sink areas in the study area, accounting for 39.93% and 33.65% of the total carbon storage, respectively. Additionally, Suzhou City's carbon storage exhibited a spatial distribution characteristic of "gradual increase from north to south." ③ The impact of land use conversion on carbon storage in Suzhou City varied. From 2000 to 2020, farmland was converted out of 1 632.758 km², resulting in a cumulative loss of carbon storage of 3 916 241.609 t, accounting for 96.9% of the total loss. Conversions from water bodies, construction land, and unused land to other land types increased the total carbon storage by 131 184.929, 140 024.741, and 18 641.031 t, respectively. ④ From the perspective of carbon sequestration, the ecological conservation scenario was significantly advantageous compared to the other three scenarios, providing strong evidence and guidance for the formulation of Suzhou City's subsequent carbon reduction policies. ⑤ The spatial differentiation of carbon storage in Suzhou City was jointly influenced by various factors, with elevation, temperature, population density, and Normalized Difference Vegetation Index （NDVI） being the main influencing factors, among which NDVI had the strongest explanatory power, reaching 0.29.