Optimization of land use planning under multi-objective demand-the case of Changchun City, China.

Modeling and scenario analysis are the core elements of land use change research, and in the face of the increasingly serious ecological and environmental problems in urbanization, it is important to carry out land use simulation studies under different protection constraints for scientific planning and policy formulation. Taking Changchun City, the capital of Jilin Province, a pilot national eco-province, as an example, a CLUE-S model with coupled landscape ecological security patterns was constructed to predict and simulate the land use structure and layout under multi-objective optimization scenarios in the planning target year (2030), and the results were analyzed based on landscape index evaluation. The study found the following: (i) the proportion of ecological land area under low, medium, and high security levels in the study area was 8.7%, 64.8%, and 26.5%, respectively; (ii) under the current development trend scenario, the trend of increasing fragmentation of cultivated land patches in Changchun in 2030 will remain unchanged, with construction land spreading along the periphery in a compact and continuous pattern, while ecological land will be seriously encroached upon; and (iii) in the 2030 multi-objective optimization scenario, land use patches of all types will begin to show a tendency to cluster, with less landscape fragmentation and more connectivity, while cultivated land and construction land will also begin to converge and do not deteriorate as a result of spatial conflicts over ecological land.

Exploring the coupling and decoupling relationship of urbanization and carbon emissions in China.

Burgeoning urbanization is a defining challenge for global carbon emissions mitigation in the coming decades. In this context, achieving low-carbon urbanization remains an urgent issue that demands prompt solutions. The coupling and decoupling relationships between urbanization and carbon emissions play an important role in the coordination of urbanization development and carbon emissions reduction, which has rarely been explored in existing studies, especially in China at the county level. To address this gap, the coupling and decoupling relationship between the urbanization level (UL) and carbon emissions density (CED) was explored using an improved coupling degree model and the Tapio decoupling method in China at the county level from 2000 to 2020. The results showed that the UL and CED of China both exhibited increasing trends, and the spatial distribution was quite similar, with the UL increasing from 0.018 in 2000 to 0.028 in 2020 and the CED increasing from 95.163 ton/km2 in 2000 to 295.746 ton/km2 in 2020. The spatial distribution of hotspots in the UL change differed with time, whereas that in the CED change was relatively stable. However, both of them were concentrated in eastern China. The coupling degrees of the UL and CED in China were 0.348, 0.355, 0.369, 0.370, and 0.338 in 2000, 2005, 2010, 2015, and 2020, respectively, with the moderately unbalanced type (>35%) being dominant at the county level and mainly scattered in eastern China. The changes in the spatial distribution patterns of the 10 subcategories were quite limited, with the systematically balanced type being dominant (89%). The decoupling types of the UL and CED during 2000-2005, 2005-2010, and 2010-2015 were weak decoupling, while those in 2015-2020 were expansive negative decoupling. At the county level, the most significant transition occurred between expansive negative decoupling, strong decoupling, and strong negative decoupling. The proportion of strong decoupling type counties peaked in 2015-2020 (70.86%), whereas that of the strong negative decoupling type counties remained high (17.55%), scattering the country. These findings can advance policy enlightenment of low-carbon urbanization and green development for China against the backdrop of "30·60 dual carbon" goal.

Construction and optimization of ecological security pattern based on the circuit theory: a case study of Hohhot City.

The construction of ecological security pattern aims to determine the bottom line of ecological land supply and effective spatial distribution and provides a scientific basis for ensuring regional ecological security. The basic paradigm of "source recognition-resistance surface creation-corridor identification-key areas determination" was used to construct the ecological security pattern of Hohhot City in 2009 and 2019. The circuit theory was employed to determine the demand for protection and restoration of crucial ecological area and to divide the core ecological protection and restoration area, the core restoration area, the core protection area, and the general ecological protection area; then, the optimization of Hohhot's ecological security pattern could be proposed. The results show that there was no interconnected and closed ecological network in 2009 and 2019 in the study area, and the area of significant ecological elements were decreasing: ecological source areas decreased from 266.97 to 261.21 km2, the number of ecological corridors decreased from 10 to 6, and the total area of ecological protection and restoration areas decreased from 342.15 to 199.91 km2. The results show that in the past 10 years, the ecological space in Hohhot had problems such as quality degradation, fragmentation intensifying, and effective landscape connectivity declining. It is urgent to optimize the ecological sources layout, strengthen the restoration of barrier areas and the protection of pinch point areas, and improve habitat connectivity to ensure the improved regional ecological security. Our results can provide a scientific reference for coordinating ecological protection and economic development, as well as the policy formulation and implementation of relevant departments.

Integrated assessment and critical obstacle diagnosis of rural resource and environmental carrying capacity with a social-ecological framework: a case study of Liyang county, Jiangsu Province.

The contradiction among human being, resources, and environment has become a significant obstacle to achieving sustainable development, especially in rural areas subject to the spillover of urban development elements. With the immense strain of resources and environment, it is critical to assess whether human activities fall within the carrying capacity range of a natural ecosystem in a rural system. Taking the rural areas of Liyang county as an example, this study aims to assess the rural resource and environmental carrying capacity (RRECC) and diagnose its critical obstacles. Firstly, a social-ecological framework focusing on human-environment interaction was employed to construct the RRECC indicator system. Subsequently, the entropy-TOPSIS method was introduced to assess the performance of the RRECC. Finally, the obstacle diagnosis method was applied to identify the critical obstacles of RRECC. Our results show that the distribution of RRECC presents a spatial heterogeneity, with high- and medium-high-level villages primarily concentrated in the south of the study area, where there are abundant hills and ecological lakes. Medium-level villages are scattered throughout each town, and low and medium-low level villages are concentrated across all the towns. Moreover, the resource subsystem of RRECC (RRECC_RS) exhibits a similar spatial distribution to RRECC, while the outcome subsystem of RRECC (RRECC_OS) has a comparable quantity proportion of different levels to RRECC. Furthermore, the diagnosis results of critical obstacle vary between the town scale divided by administrative units and the regional scale divided by RRECC values. In detail, arable land occupied by construction is the main critical obstacle at the town scale, while the poor people in villages, people left-behind, and arable land occupied by construction are the main critical obstacles at the regional scale. Targeted differentiated improvement strategies for RRECC at regional scale from various perspectives of global, local, and single are proposed. This research can serve as a theoretical foundation for assessing RRECC and developing differentiated sustainable development strategies for the path forward to rural revitalization.

The influence of urban form compactness on CO2 emissions and its threshold effect: Evidence from cities in China.

Although compact urban form plays an important role in constraining emissions of carbon dioxide (CO2), the boundary for the impact of compact urban form on these emissions has nevertheless received little attention. We consequently applied the entropy weight method and several key landscape metrics to a dataset from 295 cities in China to quantify urban form compactness (UFC) between 2000 and 2015. The STIRPAT model then was employed to estimate the impact of UFC on CO2 emissions, and a panel threshold regression model was used to estimate threshold effects capable of limiting the impact of compact urban form on emissions. Although CO2 emissions increased sharply over the 15-year study period, a significant negative relationship between UFC and CO2 emissions was detected. Two thresholds of UFC were detected, and this allowed three categories to be differentiated: before the first threshold, between the two thresholds, and after the second threshold. These categories were respectively associated with no impact, strong impact, and weak impact of UFC on reduction of carbon emissions in the 295 cities. Carbon emissions reduction consequently becomes effective when the UFC exceeds the first threshold and effectiveness persists but at a reduced level when the UFC exceeds the second threshold. Further temporal analysis confirmed that an increasing number of mostly small- and medium-sized cities could constrain their future carbon emissions by adopting a compact urban form. Thus, government policies should emphasize UFC as a strategy to reduce CO2 emissions. Moreover, by defining the range of compact urban form that has the greatest impact on CO2 emissions, our study deepens the overall understanding of the influence of UFC on carbon emission reductions, so as to make contributions to the design of low-carbon cities.

Dynamic Evolution and Spatial Convergence of the Virtual Cultivated Land Flow Intensity in China.

Exploring the flow intensity of virtual cultivated land is the key to improving the ecological compensation and food security policy. This study aimed to analyze the dynamic evolution, spatial convergence, and its affecting factors of the virtual cultivated land flow intensity. The spatial convergence model was used in this study. The results showed that, during 2000-2018, the growth rate of the surplus state of virtual cultivated land at the national level is less than that of the deficit state of virtual cultivated land in China. Moreover, the number of deficit provinces of virtual cultivated land flow intensity is increasing. The absolute ß-convergence characteristics of the virtual cultivated land flow intensity are significant at the national, northeast, central, and western regions. Additionally, the conditional ß-convergence exists at the national and four regional levels. Meanwhile, cultivated land resource endowment, population scale, regional economic development level, and agricultural mechanization level play an important role in the convergence process of inter-regional virtual cultivated land flow intensity. However, the influence degree of different control variables on different regional virtual cultivated land flow intensity is not consistent. Therefore, policymakers should pay attention to cultivated land resources' spatial transfer mechanism when making regional cultivated land ecological compensation policies to coordinate the interesting relationship between the deficit area and surplus area of virtual cultivated land. Therefore, it is necessary to take the virtual cultivated land flow intensity as the reference index and use the combination of market guidance and government control to stimulus the stakeholders to protect cultivated land by taking different measures.

Regional Differences in Ecological Compensation for Cultivated Land Protection: An Analysis of Chengdu, Sichuan Province, China.

Exploring the elements that affect farmers' willingness to protect cultivated land is the key to improving the ecological compensation mechanism for cultivated land protection. The purpose of this study was to analyze regional differences in ecological compensation for cultivated land protection, and to explore the influence of different external environments on farmers' willingness to engage in cultivated land protection. Based on the Profitable Spatial Boundary Analysis theory (PSBA), GIS spatial analysis technology was used to analyze regional space differences and assess ecological compensation for urban and rural cultivated land protection at the micro scale. The results show that the willingness of farmers to participate in cultivated land protection is affected by the external environment and the ecological compensation offered. The trend of the comprehensive benefit of cultivated land protection ecological compensation (B) is "Λ" from the first layer to the third layer. The B value of the urban-rural junction area is the highest value. This shows that the external environment is favorable for ecological compensation in this area, which has a positive effect on farmers' willingness to protect cultivated land. B < 0 in the first and third layer, which has a depressant effect on farmers' willingness to protect cultivated land. The study results contribute to the understanding of the impact of regional differences in the external environmental on ecological compensation and farmers' willingness to engage in cultivated land protection.

[The effect of "living high and training low" on serum CK, LDH and ALT of rowing athletes].

AIM: To investigate the influence of living high-training low for 4 weeks on serum CK, LDH and ALT of rowing athletes. METHODS: 20 rowing athletes were divided into two groups: the one (ten subjects) spent 8-10 h per night in a tabernacle which was simulated altitude of 2 500 m in normobaric hypoxia (HiLo group), the another (ten subjects) slept at near sea level (control group). During the periods of test, all athletes were trained at the same relative or at the same intensity of work in normoxia state. The serum CK, LDH and ALT were measured at before, during 2 weeks, 4 weeks and 2 weeks after "living high and training low". RESULTS: Baseline serum values for CK, LDH and ALT were not different between two groups (P > 0.05). The levels of CK, LDH of HiLo group were significantly increased (P < 0.05) than those of control group at 3 rd week, however, it was contrary at 5th and 7th week. After exercise of 2 km and 5 km, the values of LDH and CK at a moment notice and 30min postexercise test in HiLo group were significant lower than those in control group. CONCLUSION: These results indicate that living high-training low may reduce the muscle damage associated with endurance exercise.