[Impacts of Urban Form on Carbon Emissions Under the Goal of Carbon Emission Peak and Carbon Neutrality: A Case Study of the Yangtze River Economic Belt].

Clarifying the mechanism of influence of urban form on carbon emissions is an important prerequisite for achieving urban carbon emission reduction. Taking the Yangtze River Economic Belt as an example, this study elaborated on the general mechanism of urban form on carbon emissions, used multi-source data to quantitatively evaluate the urban form, and explored the impacts of urban form indicators on carbon emissions from 2005 to 2020 at global and sub-regional scales with the help of spatial econometric models and geodetector, respectively. The results showed that:① The carbon emissions of the Yangtze River Economic Belt increased from 2 365.31 Mt to 4 230.67 Mt, but the growth rate gradually decreased. Its spatial distribution pattern was bipolar, with high-value areas mainly distributed in core cities such as Shanghai and Chongqing and low-value areas concentrated in the western regions of Sichuan and Yunnan. ② The area of construction land in the study area expanded over the past 15 years, but the population density of construction land had been decreasing. The degree of urban fragmentation was decreasing, and the difference between cities was also progressively narrowing. The average regularity of urban shape improved, and the compactness increased significantly. ③ All indicators of urban scale had significant positive effects on carbon emissions at the global scale, urban fragmentation had a significant negative effect in 2005, and the effective mesh size (MESH) indicator of urban compactness showed a significant negative correlation with carbon emissions in the study period. ④ Total class area, patch density, and effective mesh size had the most significant impacts on carbon emissions in upstream cities. Effective mesh size, mean perimeter-area ratio, and total class area had higher influences in midstream cities. Effective mesh size, percentage of like adjacencies, and largest patch index were the key factors to promote carbon reduction in downstream cities. Cities in different regions should comprehensively consider the impacts of various urban form indicators on carbon emissions and then optimize their urban form to promote sustainable development.

Impacts of land use transitions on ecosystem services: A research framework coupled with structure, function, and dynamics.

Rapid urbanization in China has resulted in drastic land use transitions (LUT) and has had a severe impact on the supply of regional ecosystem services (ESs). To improve ecosystem security and promote sustainable development regionally, it is essential to clarify spatial correlations between the multi-dimensional characteristics of LUT and ESs. We developed a theoretical framework to examine how LUT influenced regional ESs in three dimensions: land use structure, function, and dynamics. Using the Taihu Lake Rim urban agglomeration (TLRUA) as an example, we explored the process by which LUT affected the change in regional ESs. The results indicated that the TLRUA experienced accelerated urbanization between 2000 and 2018, with LUT and ESs exhibiting distinct characteristics in urban, suburban, and rural areas in different regions. The impact of LUT on ESs, as we analyzed them from different dimensions, embraced interactive effects and significant spatial spillover effects. The land use structural transitions were globally positively correlated with habitat maintenance, carbon sequestration, and recreation potential, whereas land use intensity and dynamics transitions exhibited negative correlations. Given their interactions at the local scale, we propose corresponding land management strategies, which can offer practical guidance for coordinating regional land resource development and ecosystem conservation.