Research on the coupling coordination and driving role of urbanization and ecological resilience in the middle and lower reaches of the Yangtze River.

Background: The growth of urbanization in the 20th and 21st centuries has resulted in unprecedented ecological security issues. The imbalance between urban development and internal ecological security is a growing concern. Methods: Based on the urban development process and the characteristics of ecosystem resilience, the corresponding urbanization evaluation system ("scale-structure-benefit") and ecosystem resilience assessment model ("resistance-adaptability-restoring") were constructed to explore the changes in each dimension as well as to analyze the spatial and temporal changes and driving effects of the coupled coordination level of urbanization and ecological resilience using the coupled coordination degree (CCD) model and geographically and temporally weighted regression (GTWR). Results: (1) From 2005 to 2020, urbanization levels increased (from 0.204 to 0.264, respectively), whereas the level of ecological resilience gradually decreased (from 0.435 to 0.421, respectively). The spatial distribution of urbanization is rather steady, with a "high-northeast low-southwest" pattern of regional distribution; however, the spatial distribution pattern of ecological resilience is essentially the reverse. (2) During the study period, there was an improvement in the level of coordination between urbanization and ecological resilience, with an increase from 0.524 to 0.540. However, the main coordination type remained the same, with over 46% being at the basic coordination stage. The relative development type was dominated by the lagging urbanization stage, with the lagging ecological resilience and synchronous development stages accounting for a smaller proportion, and the space was distributed in a block-like cluster. (3) The running results of the GTWR show that the core dimensions of the whole region are scale, benefit, and structure, and the impact of each dimension shows obvious spatial heterogeneity. Cities with different levels of relative development also have different central dimensions. This research will provide support for the coordination of urban development in areas where economic construction and ecological resilience are not coordinated, and will contribute to the sustainable development of urban areas.

Assessment of ecological resilience in Nanchang based on "risk-connectivity-potential".

With the rapid development of urban construction, land for construction continues to expand and the ecological land is shrinking. There are various risks and degradation phenomena. The evaluation of urban ecological resilience thus becomes particularly important. From the perspective of urbanization-induced landscape changes, we evaluated the ecological resilience level of Nanchang from 2005 to 2020 by means of "risk-connectivity-potential" model, spatial autocorrelation model and kernel density assessment, as well as its spatial-temporal variations. The results showed that from 2005 to 2020, the spatial pattern of risk, connectivity, and potential subsystems in the study area was stable, with significant differences. The ecological risk was high in the middle and low in the east and west, while the spatial distribution of connectivity and ecological potential was opposite to the ecological risk, showing a pattern of low in the middle and high in the east and west. The overall level of ecological resilience was not high, with medium and low resilience levels as the main body. The low level continued to grow, and high value areas gradually decreased. The "high-high" cluster type of ecological resilience was decreasing, while the "low-low" cluster type was gradually increasing. Results of Kernel density assessment showed that the overall resilience level of Nanchang had little change, with obvious spatial difference. The number and distribution of different landscape types should be adjusted according to the characteristics of the ecological resilience level of different regions, in combination with the urban planning layout. The connectivity and agglomeration of spatial distribution of different landscape types should be changed to achieve the optimization and improvement of the overall regional ecological resilience level. The results could provide a theoretical basis for urban spatial planning and layout.

Spatiotemporal heterogeneity between agricultural carbon emission efficiency and food security in Henan, China.

It is significant to investigate the coupling and coordination between agricultural carbon emission efficiency (ACEE) and food security and to achieve peak carbon dioxide emissions and carbon neutrality in agriculture as early as possible while ensuring national food security. The Super-SBM (slack-based model) and the comprehensive index method were used to measure the ACEE and food security level in Henan province from 2010 to 2020. The coupling coordination degree (CCD) and the relative state of ACEE and food security were analyzed using the coupling coordination degree model (CCDM) and the relative development degree model (RDDM). In addition, the interaction between ACEE and food security and the spatial-temporal heterogeneity were analyzed by combining with the geographically and temporally weighted regression (GTWR) model. The results showed that: Firstly, the overall level of ACEE was high, and the spatial heterogeneity of ACEE was significant. The spatial pattern of food security is relatively stable, with high levels in the south and low levels in the north. Secondly, The CCD between ACEE and food security in Henan province generally shows a decreasing trend. In the spatial dimension, the CCD between ACEE and food security in Henan province exhibits a spatial divergence characteristic of low in the center and high in the north and south, with significant regional variations. Finally, there is spatial and temporal heterogeneity between ACEE and food security. The regression coefficients differ significantly among different cities, the regression coefficients do not show a consistent positive or negative correlation, and the regression coefficients are distributed both positively and negatively. This study serves as a guide for achieving the goal of double carbon in agriculture and ensuring food security.