Optimizing the ecological network of resource-based cities to enhance the resilience of regional ecological networks.

Mineral extraction in resource-based cities has caused serious damage to the original ecology, resulting in poor regional vegetation growth, reduced carbon sequestration capacity, and reduced ecosystem resilience. Especially in resource-based cities with fragile ecology, the overall anti-interference ability of the environment is relatively worse. Seeking ecological network optimization solutions that can improve vegetation growth conditions on a large scale is an effective way to enhance the resilience of regional ecosystems. This paper introduces carbon sequestration indicators and designs a differential ecological networks (ENs) optimization model (FTCC model) to achieve the goal of improving ecosystem resilience. The model identifies the patches that need to be optimized and their optimization directions based on the differences in ecological function-topology-connectivity-carbon sequestration of the patches. Finally, the resilience of the ecological network before and after optimization was compared, proving that the model is effective. The results show that the sources in the Yulin ENs form three main clusters, with connectivity between clusters relying on only a few patches. The patches in the northeastern and southwest clusters are large but their ecological functions need to be improved. After optimization, 16 new stepping stones were added, 38 new corridors were added, and the ecological function of 39 patches was enhanced. The optimized ecological network resilience was improved in terms of structure, function, and carbon sinks, and carbon sinks increased by 6364.5 tons. This study provides a reference for measures to optimize landscape space and manage ecosystem resilience enhancement in resource-based cities.

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.

The response of ecosystem vulnerability to climate change and human activities in the Poyang lake city group, China.

Ecosystem vulnerability is an ecological response of the environment to external damage. Studying the influencing factors and spatiotemporal changes of ecosystem vulnerability is helpful to maintain ecological balance. At present, studies on ecosystem vulnerability are relatively homogeneous and rarely integrate climate change and human activities. Based on a habitat-function framework, this study analyzed the response of ecosystem vulnerability on climate change and human activities in the Poyang Lake City Group (PLCG) in 2010, 2015 and 2020. The spatial agglomeration of ecosystem vulnerability has been analyzed by using GeoDa model. The interaction of factors on ecosystem vulnerability have been analyzed by using geographical detector. It can be seen that the ecosystem vulnerability of the PLCG have increased from 2010 to 2020. The impacts of climate change to the ecosystem vulnerability have showed a positive correlation. Meanwhile, the key factors leading to the change of ecological vulnerability are still human activities. This methodology demonstrates a high level of robustness when applied to other research domains. This research is conducive to maintaining the integrity of the ecosystem, realizing the development of man and nature, and promoting the sound and rapid development of economic society.

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.

Construction land suitability assessment in rapid urbanizing cities for promoting the implementation of United Nations sustainable development goals: a case study of Nanchang, China.

Cities, the main place of human settlements, are required to offer high-quality environments to citizens. To achieve this, it is essential to overcome several mega challenges of urbanization, population growth, economic development, environmental deterioration, and climate change. Urban infrastructure construction is capable of enhancing economic growth and promoting urban sustainability, while it will lead to many environmental problems if the infrastructure construction is not properly planned and designed. To address this challenge, this study aims to understand how to ensure the construction land expansion sustainably in rapidly urbanizing cities. In particular, this study analyzed the suitability of construction land expansion in Nanchang, a rapid urbanizing city in China, from 1995 to 2015. The results indicate that the urban expansion speed from 1995 to 2005 was faster than that from 2005 to 2015. The construction land in Nanchang was expanding towards "all directions" and sprawled towards surrounding districts and counties from the original core areas. Nevertheless, about 70% of the Nanchang area was allowable construction area (highly suitable expansion, relatively suitable expansion, and basically suitable expansion areas), indicating that the abundant reserved land resources for urban construction. This study also identified multiple suitability expansion paths of construction land, providing a scientific guidance for the land use planning of Nanchang city. Overall, this study provides a reference to the understanding of the construction land expansion for the achievement of United Nations sustainable development goals. It can also promote the understanding of spatial territory planning and practically enhance the capabilities of land use planning and design.

Assessment of Landscape Ecological Health: A CaseStudy of a Mining City in a Semi-Arid Steppe.

The ecological status of the semi-arid steppes in China is fragile. Under the long-term and high-intensity development of mining, the ecological integrity and biodiversity of steppe landscapes have been destroyed, causing soil pollution, grassland degradation, landscape function defect, and so on. Previous studies have mainly focused on ecosystem health assessment in mining areas. Landscape ecological health (LEH) pays more attention to the interactions between different ecosystems. Therefore, the ecological assessment of mining cities is more suitable on a landscape scale. Meanwhile, the existing LEH assessment index systems are not applicable in ecologically fragile areas with sparse population, underdeveloped economy, and in relatively small research areas. The purpose of this study was to construct a LEH assessment index system and evaluate the LEH of a mining city located in a semi-arid steppe. Xilinhot is a typical semi-arid steppe mining city in China. The contradictions between the human, land and ecological environment are serious. A new model Condition, Vigor, Organization, Resilience, and Ecosystem (CVORE) model was constructed that integrated five subsystems (services) from the perspectives of ecology, landscape ecology, mining science, and geography. This study used the CVORE model to systematically evaluate the LEH in Xilinhot city in terms of five LEH levels, including very healthy, healthy, sub-healthy, unhealthy and morbid landscape. Research results show that the areas of the very healthy, healthy, sub-healthy, unhealthy and morbid landscapes are 13.23, 736.35, 184.5, 66.76 and 20.63 km², respectively. The healthy landscapes area accounts for 72.08% and most grasslands are healthy. The sub-healthy landscapes are mainly located around areas with higher disturbances due to human activities. The morbid or unhealthy landscapes are concentrated in the mining areas. The proposed CVORE model can enrich the foundations for the quantitative assessment of Landscape Ecological Health of Mining Cities in Semi-arid Steppe (LEHMCSS). This study provided a new LEH assessment approach (CVORE model), which can support landscape ecological restoration, ecological environmental protection and urban planning of the semi-arid steppe mining cities.