Farmland transfer is an important land policy for reducing agricultural fragmentation and improving land use efficiency.Many studies have investigated the driving forces of farmland transfer at the farmers’scale.Howe...Farmland transfer is an important land policy for reducing agricultural fragmentation and improving land use efficiency.Many studies have investigated the driving forces of farmland transfer at the farmers’scale.However,the overall spatial distribution and driving mechanisms of farmland transfer at the county scale has been less quantified.In this study,we evaluated farmland transfer and its spatial pattern in Central Yunnan Urban Agglomeration(CYUA)of China by using statistical data at the county scale in 2020.A so-cial-ecological indicator system,comprising natural endowment,social indicators,economic indicators,and landscape patterns,was es-tablished to explore the relationship between farmland transfer and its driving factors.Additionally,a heuristic structural equation mod-el(SEM)was employed to disentangle direct and indirect drivers of farmland transfer.The results indicated that significant spatial clusters of farmland transfer,with high transfer rates concentrated in highly urbanized areas and low transfer rates prevalent in tradition-al ethnic minority regions.Farmland transfer is primarily driven by soil quality,landscape patterns,terrain,and social-economic rurality.Specifically,higher soil quality and improved landscape connectivity facilitate farmland transfer directly,while gentler slopes promote farmland transfer indirectly by supporting better educational opportunities and fewer minority population.Improving rural vocational training and optimizing landscape patterns through land consolidation and redistribution are important in the mountainous areas.This study can provide valuable analytical framework for farmland management for other mountainous regions.展开更多
Patna is among the cities high populated at risk of ecological and environmental deterioration due to a variety of human activities,such as poor land cover management.One of the most crucial elements of a successful l...Patna is among the cities high populated at risk of ecological and environmental deterioration due to a variety of human activities,such as poor land cover management.One of the most crucial elements of a successful land resource management plan is the evaluation of Land Use Land Cover(LULC).Over the past 20 years,our planet’s land cover resources have undergone substantial changes due to rapid development.The Land Use Land Cover(LULC)categories of the Patna Urban Agglomeration(PUA),including water bodies,agricultural land,barren land,built-up areas,and vegetation,were identified using Geographic Information System(GIS)techniques.Three multi-temporal images were analyzed and classified through supervised classification using the maximum likelihood method.By comparing three separately created LULC categorized maps from 1990 and 2024,temporal changes were analyzed.In order to update land cover or manage natural resources,it is vital to use change detection as a tool to identify changes in LULC over time in PUA,Patna between 1990,2010 and 2024.According to their respective Kappa coefficients,the accuracy rates for 1990,2010 and 2024 LULC are 91.66 and 94.93,respectively.An accuracy evaluation was conducted to determine the correctness of the classification system and to determine the efficacy of the LULC classification maps.One hundred reference test pixels were identified.There have been found significant changes in the LULC were built up area has increased doubled in last thirty-four years of timeline.展开更多
This study focuses on urgent research on restoring and enhancing carbon storage capacity in the Beibu Gulf Urban Agglomer-ation of China,a key area in the‘Belt and Road’Initiative,which aligns with carbon peaking an...This study focuses on urgent research on restoring and enhancing carbon storage capacity in the Beibu Gulf Urban Agglomer-ation of China,a key area in the‘Belt and Road’Initiative,which aligns with carbon peaking and neutrality goals.This research ana-lyzes the spatial characteristics of carbon metabolism from 2000 to 2020 and uses models to identify stable carbon sink areas,positive carbon flow corridors,and carbon sequestration nodes.The goal is to construct a carbon metabolism spatial security pattern(CMSSP)and propose territorial ecological restoration strategies under different development demand scenarios.The results show the following:1)in 2020,the study area’s carbon sink decreased by 8.29×10^(4) t C/yr compared with that in 2010 and by 10.83×10^(4) t C/yr compared with that in 2000.High-carbon sinks were found mainly in mountainous areas,whereas low-carbon sinks are concentrated in urban con-struction land,rural residential areas,and land margins.2)From 2000 to 2020,the spatial security pattern of carbon metabolism tended to be‘high in the middle of the east and west and low in the gulf.’In 2000,2010,and 2020,16 stable carbon sinks were identified.The carbon energy flow density in Guangxi was greater than that in Guangdong and Hainan,with positive carbon flow corridors located primarily in Guangxi and Guangdong.The number of carbon sequestration nodes remained stable at approximately 15,mainly in Guangxi and Hainan.3)Scenario simulations revealed that under the Nature-based mild restoration scenario,the carbon sink rate will reach 611.85×10^(4) t C/yr by 2030 and increase to 612.45×10^(4) t C/yr by 2060,with stable carbon sinks increasing to 18.In the restora-tion scenario based on Anti-globalization,the carbon sink will decrease from 610.24×10^(4) t C/yr in 2030 to 605.19×10^(4) t C/yr in 2060,with the disappearance of some positive carbon flow corridors and stable carbon sinks.Under the Human-based sustainable restoration scenario,the carbon sink area will decrease from 607.00×10^(4) t C/yr in 2030 to 596.39×10^(4) t C/yr in 2060,with carbon sink areas frag-menting and positive carbon flow corridors becoming less dense.4)On the basis of the current and predicted CMSSPs,this study ex-plores spatial ecological restoration strategies for high-carbon storage areas in bay urban agglomerations at four levels:the land control region,urban agglomeration structure system,carbon sink structure and bay structure control region.展开更多
Digital transformation,as a recent trend in socioeconomic development,is considered as a critical pathway for urban carbon reduction because of its potential to increase productivity and energy efficiency.However,few ...Digital transformation,as a recent trend in socioeconomic development,is considered as a critical pathway for urban carbon reduction because of its potential to increase productivity and energy efficiency.However,few studies have explored the relationship between urban digitalization and carbon emissions(CE).Therefore,this study systematically analyzed the spatiotemporal distribution and interaction mechanism between digitalization and CE in the Yangtze River Delta(YRD)urban agglomerations of China during 2006-2020 based on a multidimensional indicator system,including digitalization industry level,digitalization application level,and urban green digitalization willingness.The findings revealed that both digitalization and CE in the YRD exhibit a significant and synchronously evolving“core-periphery”spatial pattern.Core cities generated substantial positive spillover effect on periphery cities through technology diffusion and policy demonstration,advancing both regional digitalization and the collaborative governance of CE.However,digitalization had dual impact on CE.On the one hand,it promoted the reduction of CE by enhancing energy efficiency,optimizing industrial structures,and promoting the application of green technologies.On the other hand,the expansion of digital infrastructure introduced a potential risk of increased energy consumption.Therefore,targeted policy recommendations are proposed to facilitate the coordination of environmental sustainability and digitalization in the YRD.This study provides empirical support and policy insights for advancing the coordinated development of regional digital transformation and green low-carbon initiatives.展开更多
Low-carbon urban development in China can pave the way to achieve the dualcarbon goal.Exploring how land use changes(LUCs)impact carbon storage(CS)under multi-climate scenarios in different urban agglomerations helps ...Low-carbon urban development in China can pave the way to achieve the dualcarbon goal.Exploring how land use changes(LUCs)impact carbon storage(CS)under multi-climate scenarios in different urban agglomerations helps to formulate differential scientific carbon mitigation policies.In this regard,this study constructs an integrated model of SD-PLUS-InVEST to simulate LUCs and CS changes under multi-climate change-based scenarios(SSP126,SSP245,SSP585)for three major urban agglomerations(3UAs)in the Yangtze River Economic Belt.Results demonstrate that land use demand in the 3UAs changes considerably in each scenario.Construction land in the 3UAs remains the most important growth category for the coming decade,but its increase varies in different scenarios.CS in the Yangtze River Delta Urban Agglomeration(YRDUA)and Mid-Yangtze River Urban Agglomeration(MYRUA)shows a similar downward trend under different scenarios,with scenario SSP245 decreasing the most,to 184,713.526 Tg and 384,459.729 Tg,respectively.CS in the Cheng-Yu(Chengdu-Chongqing)Urban Agglomeration(CYUA)exhibits the opposite upward trend,with scenario SSP126 increasing the most to 153,007.973 Tg.The major cause of CS loss remains the conversion of forest land to construction land in the YRDUA and MYRUA under different scenarios.However,in the CYUA,the conversion of forest land to cultivated land is the major driver of CS loss under scenario SSP126.In contrast,the conversion of cultivated land to construction land dominantly drives CS loss under scenarios SSP245 and SSP585.The conversion of water body to other land use types is the major cause of CS gain in the YRDUA and MYRUA under different scenarios.At the same time,in the CYUA,the driver is the conversion of cultivated land to forest land.These findings demonstrate the significance of the low-carbon development in urban agglomerations at different development stages at home and abroad.展开更多
Dryland regions face complex interactions between urbanization and ecological changes,where effective coordination is essential for enhancing sustainability and resilience.However,most studies concentrate on the natio...Dryland regions face complex interactions between urbanization and ecological changes,where effective coordination is essential for enhancing sustainability and resilience.However,most studies concentrate on the national or provincial scales,with insufficient research on county-level coordination,limiting the ability to provide targeted polifrom a precise perspective.This study addresses this gap by analyzing 39 counties within the Hohhot-Baotou-Ordos-Yulin Urban Agglomeration(HBOYUA),a typical dryland urban cluster in China.We use daytime and nighttime remote sensing images to track the spatio-temporal evolution of urbanization and ecological conditions from 1992 to 2023.A novel quantitative framework based on an improved coupling coordination degree(CCD)is proposed to assess their coordination relationship.The results reveal that:(1)Urbanization and ecological quality both exhibited fluctuating upward trends,with spatial heterogeneity increasing for urbanization and decreasing for the eco-environment.Regions with better ecological conditions had higher urbanization levels.(2)The overall coordinated level improved from imbalance(0.36)to low-level coordination(0.55),although its spatial distribution remained uneven,with central urban areas showing higher CCD than surrounding counties.(3)Socioeconomic factors exerted greater effects on CCD than natural factors,with GDP and land surface temperature(LST)playing a significant role in interaction analysis.(4)In western arid regions,urbanization did not necessarily harm ecosystems;instead,ecological conditions improved alongside urbanization.This research offers targeted and valuable references for county and city governments in resource allocation and sustainable development.The proposed methodology is also adaptable for urban resilience studies in other regions.展开更多
Research on urban health constitutes an important issue in the field of health geography and also a strong propeller of the Healthy China Initiative.As the main form that realizes new-type urbanization,urban agglomera...Research on urban health constitutes an important issue in the field of health geography and also a strong propeller of the Healthy China Initiative.As the main form that realizes new-type urbanization,urban agglomerations should become the primal sites for the construction of a“Healthy China”.The evaluation of healthy cities’development in urban agglomerations has both theoretical and practical values.Based on the concept of urban health and its evaluation models,this paper developed an evaluation framework for healthy cities that involved multiple data sources.With 19 urban agglomerations in China as the research subjects,we used CRITIC weighting and geographical detectors to examine the geographies of healthy cities and their influencing factors in 2010 and 2020.The results were fourfold.Firstly,the urban health level of China significantly increased from 2010 to 2020,and the comprehensive health index developed towards a positive skewed distribution,along with a shift from“low in the hinterland-high in the coastal areas”to a“multipolar”pattern led by the coastal and southwest urban agglomerations.Secondly,among various dimensions of urban health,the healthy environment index became improved with narrowed regional differences;while the health services index was still polarized;health collaboration was upgraded with a strengthened intercity health network;the healthy population index slightly declined and converged to the middle.Thirdly,urban health in China has initially demonstrated the characteristics of a H-H pattern in the Yangtze River Delta and ChengduChongqing regions,as well as L-L clusters in the northern urban agglomerations,the narrowed regional differences,and increasing coordination within each urban agglomeration.Fourthly,the geographical detector found that economy,urbanization and the human capital were significant external factors that affected urban health development.The explanatory power of technological innovation and opening to the outside world were also increasing.The development of healthy cities is yet to be transformed into regional health integration.展开更多
Green space plays an important role in the sustainable urban development.This study proposes the Green Lighting Index(GLI),integrating nighttime light data from SDGSAT-1 and theNormalized DifferenceVegetation Index(ND...Green space plays an important role in the sustainable urban development.This study proposes the Green Lighting Index(GLI),integrating nighttime light data from SDGSAT-1 and theNormalized DifferenceVegetation Index(NDVI)from Sentinel-2,to explore the nighttime human activity in green spaces across three major urban agglomerations in China:Beijing-Tianjin-Hebei(BTH),the Yangtze River Delta(YRD),and the Greater Bay Area(GBA).The findings reveal that,for most green spaces,the relationship between nighttime lighting and green spaces is predominantly exclusionary.However,a synergistic relationship is observed in some vibrant green spaces characterized by abundant nighttime lighting.This synergy is evident in high GLI levels,which are strongly positively correlated with per capita Gross Domestic Product(GDP).This research underscores the importance of integrating nighttime perspectives into green space studies.We believe GLI could be used in the assessment of green space quality and contribute to the development of sustainable cities.展开更多
Studying the spatiotemporal variation and driving mechanisms of vegetation net primary productivity(NPP)in the Guanzhong Plain Urban Agglomeration(GPUA)of China is highly important for regional green and low-carbon de...Studying the spatiotemporal variation and driving mechanisms of vegetation net primary productivity(NPP)in the Guanzhong Plain Urban Agglomeration(GPUA)of China is highly important for regional green and low-carbon development.This study used the Theil-Sen trend analysis,Mann-Kendall trend test,coefficient of variation,Hurst index,and machine learning method(eXtreme Gradient Boosting and SHapley Additive exPlanations(XGBoost-SHAP))to analyze the spatiotemporal variation of NPP in the GPUA from 2001 to 2020 and reveal its response to climate change and human activities.The results found that during 2001-2020,the averageNPP in the GPUA showed a significant upward trend,with an annual growth rate of 10.84 g C/(m^(2)•a).The multi-year average NPP in the GPUA was 484.83 g C/(m^(2)•a),with higher values in the southwestern Qinling Mountains and lower values in the central and northeastern cropland and built-up areas.The average coefficient of variation of NPP in the GPUA was 0.14,indicating a relatively stable state overall,but 72.72%of the study area showed weak anti-persistence,suggesting that NPP in most areas may have declined in the short term.According to XGBoost-SHAP analyses,elevation,land use type and precipitation were identified as the main driving factors of NPP.Appropriate precipitation and higher temperatures promote NPP growth,whereas extreme climates,high population density,and nighttime lighting inhibit NPP.This study has important theoretical and practical significance for achieving regional sustainable development,offers a scientific basis for formulating effective ecological protection and restoration strategies,and promotes green,coordinated,and sustainable development in the GPUA.展开更多
Taking 18 large-scale urban agglomerations(UAs)in China as the research objects,this study analyzes the characteristics of the spatiotemporal patterns of carbon emissions in UA areas in China and their impact mechanis...Taking 18 large-scale urban agglomerations(UAs)in China as the research objects,this study analyzes the characteristics of the spatiotemporal patterns of carbon emissions in UA areas in China and their impact mechanisms by citing Moran’s I and geographically weighted regression(GWR).The research findings are as follows:1)obvious differences are found in carbon emissions among different UAs.The cities with higher absolute carbon emissions are mainly distributed in the major cities of the Hohhot-Baotou-Ordos-Yulin UA.2)From 2011 to 2021,the carbon emission levels of China’s UAs grew obviously,but the spatial differences are pronounced,among which the Hohhot-Baotou-Ordos-Yulin UA and others had the highest growth rates.The carbon emission patterns of UAs also present obvious spatial clustering characteristics.The regions with the most obvious growth rates of carbon emissions at the urban scale are mainly distributed in the Hohhot-Baotou-Ordos-Yulin UA and Mid-Yangtze River UA.3)The value of secondary industry(X_(vsi)),number of urban enterprises(X_(nue)),public library holdings(X_(plh)),and urban passenger volume(X_(upv))have an obvious effect on carbon emissions.However,the regression cofficients exhibit obvious spatial variation.Among them,X_(vsi) has an obvious positive effect on carbon emissions,indicating that spatial agglomeration of the real economy substantially increases reginal carbon emission levels.The high X_(nue)regression coefficients are mainly distributed in Harbin-Changchun UA,indicating that the growth of enterprises in this region is still dominated by traditional high-carbon-emission enterprises,the urgent task of low-carbon transformation and upgrading for traditional industries in old industrial regions.The regression coefficients of X_(plh)and X_(upv) are generally negative,suggesting that improving public service facilities and strengthening regional transportation links can help to reduce the level of carbon emissions.展开更多
Exploring the spatiotemporal changes in Fractional Vegetation Coverage(FVC)helps to more accurately understand the quality of the ecological environment,which is of great significance for regional ecological protectio...Exploring the spatiotemporal changes in Fractional Vegetation Coverage(FVC)helps to more accurately understand the quality of the ecological environment,which is of great significance for regional ecological protection and sustainable economic development.The study takes the Chengdu-Chongqing urban agglomeration as the research area,analyzes the characteristics and trends of vegetation cover changes from 2000 to 2020 using the Google Earth Engine cloud platform,and explores its driving factors based on the enhanced regression tree model.The results show that:(1)From 2000 to 2020,the annual FVC of the Chengdu-Chongqing urban agglomeration showed a fluctuating upward trend,with a stable phase from 2000 to 2003 and an upward phase from 2003 to 2020.(2)During the research period,most areas within the agglomeration exhibited negligible changes in FVC.In contrast,other areas showed a complex pattern of both vegetation degradation and improvement.The areas with improved FVC were sporadically distributed,accounting for 15.08% of the total area,whereas areas with substantial vegetation degradation constituted 11.60%.(3)The FVC in the Chengdu-Chongqing urban agglomeration is predominantly influenced by four key factors:population dynamics,forestrymanagement practices,annual sunshine duration,and annual precipitation.Collectively,these factors account for 99.31%of the variation in FVC,with anthropogenic factors(population dynamics and forestry management)exerting the most significant influence.展开更多
Due to the multiple impacts of global climate change and anthropogenic disturbances,regional ecological landscapes have been developing towards fragmentation.How to quantitatively measure regional ecological landscape...Due to the multiple impacts of global climate change and anthropogenic disturbances,regional ecological landscapes have been developing towards fragmentation.How to quantitatively measure regional ecological landscape fragmentation and identify its key drivers is an important foundation for regional biodiversity conservation and ecosystem restoration.Taking the Guanzhong Plain Urban Agglomeration(GPUA),China as the research object,this paper proposes a comprehensive framework that integrates landscape pattern index,principal component analysis,random forest(RF)and other methods to quantitatively analyze the spatial and temporal evolution of ecological landscape fragmentation and its driving factors.The results show that:1)cropland,forestland and grassland showed significant spatial differentiation in the landscape pattern index,and the change of their mean values indicated that cropland and forestland show a trend of‘little decrease-continuous increase’.Spatially,the northwestern and southeastern regions showed significant fragmentation and prominent spatial heterogeneity.2)From 2010 to 2020,the landscape fragmentation of cropland and forestland increased by 71%and 20%,respectively,while that of grassland decreased by 33%,indicating that the degree of landscape fragmentation of cropland changed more drastically than that of other ecological land.3)It was found that slope was the most important factor affecting landscape fragmentation of ecological land.In addition,road density had a significant effect on landscape fragmentation of cropland and forestland,but the min-distance between patches and the county center had an important effect on landscape fragmentation of grassland.This study can provide theoretical references for urban agglomeration planning and sustainable landscape management on a regional scale.展开更多
Understanding the evolutionary trends and driving factors behind extreme hourly precipitation(EHP)in typical urban agglomerations is crucial for predicting and preventing rapid floods.We collected hourly precipitation...Understanding the evolutionary trends and driving factors behind extreme hourly precipitation(EHP)in typical urban agglomerations is crucial for predicting and preventing rapid floods.We collected hourly precipitation datasets from 31 observation stations in the Central Yunnan Urban Agglomeration(CYA)spanning from 2004 to 2020.Urban and rural observations were dynamically classified based on impervious surface fraction.Linear(Granger)and nonlinear causal methods(convergent cross-mapping and Liang–Kleeman information flow)were used to identify the causal impact mechanisms of large-scale circulation,environment and urbanization on EHP.Moreover,geo-detector further reveals the spatial influence of these factors and their interactions on EHP.Our findings revealed that EHP mainly occurred in the afternoon and at midnight.Also,the frequency and intensity of EHP in the CYA significantly(p≤0.05)increased from 2004 to 2020,especially in urban areas.The increasing rate in urban areas was higher than that in rural areas.However,the duration of EHP/hourly total precipitation exhibited a significant/nonsignificant decreasing trend with no significant difference between urban and rural areas.Causality tests and geo-detector indicated that EHP was impacted by natural variability and urbanization.Large-scale circulation indices such as the Pacific Decadal Oscillation,El Ni?o-Southern Oscillation,and Indian Ocean Dipole nonlinearly influenced EHP.Additionally,urban landscape layout,vegetation,and population variation may strengthen EHP by changing environmental factors such as temperature and relative humidity.Interactions exist between these factors and influence EHP,although large-scale circulation remains the dominant influence.With global climate warming and rapid urbanization in the CYA,the frequency and intensity of EHP may further amplify in the future.展开更多
Wetlands offer important ecological functions and values.Wetland functional zoning provides a reference and basis for sustainable fulfilment and management.In this study,two coastal urban agglomerations in South China...Wetlands offer important ecological functions and values.Wetland functional zoning provides a reference and basis for sustainable fulfilment and management.In this study,two coastal urban agglomerations in South China were taken as study areas,namely,the Guangxi Beibu Gulf(GBG)and Guangdong-Hong Kong-Macao Greater Bay Area(GBA).Based on multisource information data,a wetland functional zoning system was constructed with the four levels of zoning concept,zoning principle,zoning basis,and zoning scheme.The functional zoning and dynamic analysis of wetlands from 1990 to 2020 were carried out from multiple perspectives of wetland ecological functions,wetland management and conservation functions.The results showed that:1)in terms of wetland ecological functions,the two coastal urban agglomerations were dominated by hydrological regulation and purification of environmental functional areas.The coastal region was largely characterized by the main functional areas of climate regulation and biodiversity maintenance.2)Regarding wetland management and conservation functions,two coastal urban agglomerations exhibited similar trends in terms of the sizes of their conservation and buffer zones from 1990 to 2020.Prevention and control zones were mainly located in core cities in a concentrated manner.Conservation zones largely comprised mountainous woodlands and important wetlands.3)The two coastal urban agglomerations could be divided into 21 wetland functional zones.The central river area has remained the main prevention and control zone for many years.Regarding conservation zones,ecological protection and restoration should be the main focus.Regarding buffer zones,the construction of wetlands and surrounding complex systems should be strengthened or enhanced.Regarding prevention and control zones,activities that do not affect wetland functions should be allowed,provided that they comply with existing laws and regulations.This study could provide technical support and practical application guidance for wetland regulation and management.展开更多
China is one of the countries with the longest history in the world.The protection and development of historical and cultural resources is an issue worthy of attention in the fields of economic geography and urban-rur...China is one of the countries with the longest history in the world.The protection and development of historical and cultural resources is an issue worthy of attention in the fields of economic geography and urban-rural planning at the present stage.This study takes the Zhongyuan Urban Agglomeration,which is rich in historical and cultural heritage,as a specific case,analyzes the characteristics of the spatial-temporal distribution pattern of its historical and cultural resources.The results show that the distribution structure of historical and cultural element resources within the Zhongyuan Urban Agglomeration presents significant regional agglomeration and combination characteristics.In response to the analysis results,the study formulates an optimization strategy for the regional development pattern supported by the protection and development of historical and cultural resources,and initially proposes a matching spatial development pattern plan and policy recommendations for coordinated development.展开更多
Promoting positive urban–rural interactions is a key strategy for addressing rural decline and advancing regional sustainable development.This study examines the impacts of urban–rural interactions on rural developm...Promoting positive urban–rural interactions is a key strategy for addressing rural decline and advancing regional sustainable development.This study examines the impacts of urban–rural interactions on rural development and explores their mechanisms for advancing sustainability within urban agglomeration areas.Using the Chang–Zhu–Tan(CZT)urban agglomeration as a case study,with an indicator system to measure urban–rural interactions and rural sustainable development,we analyze the mediating effects of resource flows in the process of urban–rural interactions driving rural sustainability through a mediation model.The results show that spatial connectivity,industrial convergence,and social integration between urban and rural areas positively contribute to the economic and social sustainability of rural areas.However,urban–rural spatial connectivity and social integration may negatively impact on rural environment.In this process,capital,technology,and labor play significant mediating roles,whereas the influence of land is less pronounced.Based on these findings,we propose several recommendations for strategically leveraging the benefits of urban–rural interactions across various social-ecological contexts while mitigating their drawbacks.展开更多
This study constructs a quasi-natural experiment based on the expansion of the Yangtze River Delta urban agglomeration(YRDUA) of China in 2010 to investigate the impact and inner mechanism of urban agglomeration expan...This study constructs a quasi-natural experiment based on the expansion of the Yangtze River Delta urban agglomeration(YRDUA) of China in 2010 to investigate the impact and inner mechanism of urban agglomeration expansion on fine particulate matter(PM_(2.5)) concentrations through propensity scores in difference-in-differences models(PSM-DID) using panel data from 286 prefecturelevel cities in China from 2003 to 2016. The results show that 1) urban agglomeration expansion contributes to an overall decrease in PM_(2.5)concentration, which is mainly achieved from the original cities. For the new cities, on the other hand, the expansion significantly increases the local PM_(2.5)concentration. 2) In the long term, the significant influence of urban agglomeration expansion on PM_(2.5)concentration lasts for three years and gradually decreases. A series of robustness tests confirm the applicability of the PSM-DID model.3) Cities with weaker government regulation, a better educated population and higher per capita income present stronger PM_(2.5)reduction effects. 4) Urban agglomeration expansion affects the PM_(2.5)concentration mainly through industrial transfer and population migration, which cause a decrease in the PM_(2.5)concentration in the original cities and an increase in the PM_(2.5)concentration in the new cities.Corresponding policy suggestions are proposed based on the conclusions.展开更多
The inter-city linkage heat data provided by Baidu Migration is employed as a characterization of inter-city linkages in order to facilitate the study of the network linkage characteristics and hierarchical structure ...The inter-city linkage heat data provided by Baidu Migration is employed as a characterization of inter-city linkages in order to facilitate the study of the network linkage characteristics and hierarchical structure of urban agglomeration in the Greater Bay Area through the use of social network analysis method.This is the inaugural application of big data based on location services in the study of urban agglomeration network structure,which represents a novel research perspective on this topic.The study reveals that the density of network linkages in the Greater Bay Area urban agglomeration has reached 100%,indicating a mature network-like spatial structure.This structure has given rise to three distinct communities:Shenzhen-Dongguan-Huizhou,Guangzhou-Foshan-Zhaoqing,and Zhuhai-Zhongshan-Jiangmen.Additionally,cities within the Greater Bay Area urban agglomeration play different roles,suggesting that varying development strategies may be necessary to achieve staggered development.The study demonstrates that large datasets represented by LBS can offer novel insights and methodologies for the examination of urban agglomeration network structures,contingent on the appropriate mining and processing of the data.展开更多
Urban agglomerations are an inevitable outcome of China＇s new national industrialization and urbanization reaching relatively advanced stages of development over the past 30 years. In the early 2000 s, urban agglomer...Urban agglomerations are an inevitable outcome of China＇s new national industrialization and urbanization reaching relatively advanced stages of development over the past 30 years. In the early 2000 s, urban agglomerations became new geographical units for participating in global competition and the international division of labor, and China has spent the past decade promoting them as the main spaces for pushing forward its new form of urbanization. The convening of the first Central Work Conference on Urbanization and the National New-type Urbanization Plan（2014–2020） further defined the status of urban agglomerations as the main players in promoting China＇s new type of national urbanization. Nevertheless, urban agglomerations remain a weak link in Chinese academia and are in urgent need of study. Only 19 articles on the theme of urban agglomerations were published in the journal Acta Geographica Sinica between 1934 and 2013, accounting for only 0.55% of all articles written during that period. Not only are there very few, they have also all been published within a relatively short period of time, with the first having been published only 10 years ago. The studies are also concentrated among only a few authors and institutions, and research is aimed at national requirements but is rather divergent. Even so, some studies on urban agglomerations have played a leading role and made important contributions to dictating the overall formation of urban agglomerations nationwide. Specifically, a proposed spatial pattern for urban agglomerations formed the basic framework for the spatial structure of China＇s urban agglomerations and guided the government to make urban agglomerations the main urban pattern when promoting the new type of urbanization; proposed standards and technologies for identifying the spatial dimensions of urban agglomerations played an important role in defining the scope of national urban agglomerations; a series of studies in the area of urban agglomerations spurred more in-depth and practical studies in the field; and studies on issues related to the formation and growth of urban agglomerations provided warnings on the future selection and development of urban agglomerations. Taking the progress and results of these studies as a foundation, the foci of selecting and developing urban agglomerations in China are as follows： to be problem-oriented and profoundly reflect on and review new problems exposed in the selection and development of urban agglomerations; to concentrate on urban agglomerations and lay importance on the formation of a new “5＋9＋6” spatial structure for China＇s urban agglomerations; to rely on urban agglomerations and promote the formation of a new pattern of national urbanization along the main axes highlighted by urban agglom-erations; to be guided by national strategic demand and continue to deepen understanding of major scientific issues in the course of the formation and development of urban agglomerations, including studying the resource and environmental effects of high-density urban agglomerations, scientifically examining resource and environmental carrying capacities of high-density urban agglomerations, creating new management systems and government coordination mechanisms for the formation and development of urban agglomerations, studying the establishment of public finance systems and public finance reserve mechanisms for urban agglomerations, and studying and formulating technical specifications for urban agglomeration planning and standards for delineating urban agglomeration boundaries.展开更多
Due to its great strategic significance in integrating regional coordinated development and enhancing the rise of Central China, urban agglomeration in the middle reaches of Changjiang （Yangtze） River has attracted ...Due to its great strategic significance in integrating regional coordinated development and enhancing the rise of Central China, urban agglomeration in the middle reaches of Changjiang （Yangtze） River has attracted much attention from both theoretical and practical aspects. Such research into the area＇s economic network structure is beneficial for the formation of an urban- and regional-development strategy. This paper constructs an economic tie model based on a modified gravitation model. Subsequently, referring to social network analysis, the paper empirically studies the network density, network centrality, subgroups and structural holes of the middle reaches of Changjiang River＇s urban agglomeration economic network. The findings are fourfold： （1） an economic network of urban agglomeration in the middle reaches of Changjiang River has been formed, and economic ties between the cities in this network are comparatively dense; （2） the urban agglomeration in the middle reaches of Changjiang River can be divided into four significant subgroups, with each subgroup having its own obvious economic communications, while there is less economic-behavioral heterogeneity among subgroups - this is especially true for the two subgroups that exist in the Poyang Lake Ecological Economic Zone; （3） an economy pattern driven by the central cities of Wuhan, Changsha and Nanchang has emerged in the urban agglomeration of the middle reaches of Changjiang River, while these three capital cities have exerted great radiation abilities to their surrounding cities, the latter are less able to absorb resources from the former （4） the Wuhan Metropolitan Areas and the Poyang Lake Ecological Economic Zone have more structural holes than the Ring of Changsha, Zhuzhou and the Xiangtan City Clusters, meaning that cities at the periphery of these two areas are easily constrained by central cities. The Ring of Changsha, Zhuzhou and the Xiangtan City Clusters have fewer structural holes; thus, the cities in this area will not face as many constraints as those in the other two areas.展开更多
基金Under the auspices of Yunnan Provincial Science and Technology Project at Southwest United Graduate School(No.202302AO370012)National Natural Science Foundation of China(No.42201290)+1 种基金Talent Introduction Fund of Yunnan University(No.CZ22623101)the Fourteenth Program of Research Innovation Fund for Graduate Students of Yunnan University(No.KC-22221099)。
文摘Farmland transfer is an important land policy for reducing agricultural fragmentation and improving land use efficiency.Many studies have investigated the driving forces of farmland transfer at the farmers’scale.However,the overall spatial distribution and driving mechanisms of farmland transfer at the county scale has been less quantified.In this study,we evaluated farmland transfer and its spatial pattern in Central Yunnan Urban Agglomeration(CYUA)of China by using statistical data at the county scale in 2020.A so-cial-ecological indicator system,comprising natural endowment,social indicators,economic indicators,and landscape patterns,was es-tablished to explore the relationship between farmland transfer and its driving factors.Additionally,a heuristic structural equation mod-el(SEM)was employed to disentangle direct and indirect drivers of farmland transfer.The results indicated that significant spatial clusters of farmland transfer,with high transfer rates concentrated in highly urbanized areas and low transfer rates prevalent in tradition-al ethnic minority regions.Farmland transfer is primarily driven by soil quality,landscape patterns,terrain,and social-economic rurality.Specifically,higher soil quality and improved landscape connectivity facilitate farmland transfer directly,while gentler slopes promote farmland transfer indirectly by supporting better educational opportunities and fewer minority population.Improving rural vocational training and optimizing landscape patterns through land consolidation and redistribution are important in the mountainous areas.This study can provide valuable analytical framework for farmland management for other mountainous regions.
文摘Patna is among the cities high populated at risk of ecological and environmental deterioration due to a variety of human activities,such as poor land cover management.One of the most crucial elements of a successful land resource management plan is the evaluation of Land Use Land Cover(LULC).Over the past 20 years,our planet’s land cover resources have undergone substantial changes due to rapid development.The Land Use Land Cover(LULC)categories of the Patna Urban Agglomeration(PUA),including water bodies,agricultural land,barren land,built-up areas,and vegetation,were identified using Geographic Information System(GIS)techniques.Three multi-temporal images were analyzed and classified through supervised classification using the maximum likelihood method.By comparing three separately created LULC categorized maps from 1990 and 2024,temporal changes were analyzed.In order to update land cover or manage natural resources,it is vital to use change detection as a tool to identify changes in LULC over time in PUA,Patna between 1990,2010 and 2024.According to their respective Kappa coefficients,the accuracy rates for 1990,2010 and 2024 LULC are 91.66 and 94.93,respectively.An accuracy evaluation was conducted to determine the correctness of the classification system and to determine the efficacy of the LULC classification maps.One hundred reference test pixels were identified.There have been found significant changes in the LULC were built up area has increased doubled in last thirty-four years of timeline.
基金Under the auspices of the National Natural Science Foundation of China(No.52268008)。
文摘This study focuses on urgent research on restoring and enhancing carbon storage capacity in the Beibu Gulf Urban Agglomer-ation of China,a key area in the‘Belt and Road’Initiative,which aligns with carbon peaking and neutrality goals.This research ana-lyzes the spatial characteristics of carbon metabolism from 2000 to 2020 and uses models to identify stable carbon sink areas,positive carbon flow corridors,and carbon sequestration nodes.The goal is to construct a carbon metabolism spatial security pattern(CMSSP)and propose territorial ecological restoration strategies under different development demand scenarios.The results show the following:1)in 2020,the study area’s carbon sink decreased by 8.29×10^(4) t C/yr compared with that in 2010 and by 10.83×10^(4) t C/yr compared with that in 2000.High-carbon sinks were found mainly in mountainous areas,whereas low-carbon sinks are concentrated in urban con-struction land,rural residential areas,and land margins.2)From 2000 to 2020,the spatial security pattern of carbon metabolism tended to be‘high in the middle of the east and west and low in the gulf.’In 2000,2010,and 2020,16 stable carbon sinks were identified.The carbon energy flow density in Guangxi was greater than that in Guangdong and Hainan,with positive carbon flow corridors located primarily in Guangxi and Guangdong.The number of carbon sequestration nodes remained stable at approximately 15,mainly in Guangxi and Hainan.3)Scenario simulations revealed that under the Nature-based mild restoration scenario,the carbon sink rate will reach 611.85×10^(4) t C/yr by 2030 and increase to 612.45×10^(4) t C/yr by 2060,with stable carbon sinks increasing to 18.In the restora-tion scenario based on Anti-globalization,the carbon sink will decrease from 610.24×10^(4) t C/yr in 2030 to 605.19×10^(4) t C/yr in 2060,with the disappearance of some positive carbon flow corridors and stable carbon sinks.Under the Human-based sustainable restoration scenario,the carbon sink area will decrease from 607.00×10^(4) t C/yr in 2030 to 596.39×10^(4) t C/yr in 2060,with carbon sink areas frag-menting and positive carbon flow corridors becoming less dense.4)On the basis of the current and predicted CMSSPs,this study ex-plores spatial ecological restoration strategies for high-carbon storage areas in bay urban agglomerations at four levels:the land control region,urban agglomeration structure system,carbon sink structure and bay structure control region.
文摘Digital transformation,as a recent trend in socioeconomic development,is considered as a critical pathway for urban carbon reduction because of its potential to increase productivity and energy efficiency.However,few studies have explored the relationship between urban digitalization and carbon emissions(CE).Therefore,this study systematically analyzed the spatiotemporal distribution and interaction mechanism between digitalization and CE in the Yangtze River Delta(YRD)urban agglomerations of China during 2006-2020 based on a multidimensional indicator system,including digitalization industry level,digitalization application level,and urban green digitalization willingness.The findings revealed that both digitalization and CE in the YRD exhibit a significant and synchronously evolving“core-periphery”spatial pattern.Core cities generated substantial positive spillover effect on periphery cities through technology diffusion and policy demonstration,advancing both regional digitalization and the collaborative governance of CE.However,digitalization had dual impact on CE.On the one hand,it promoted the reduction of CE by enhancing energy efficiency,optimizing industrial structures,and promoting the application of green technologies.On the other hand,the expansion of digital infrastructure introduced a potential risk of increased energy consumption.Therefore,targeted policy recommendations are proposed to facilitate the coordination of environmental sustainability and digitalization in the YRD.This study provides empirical support and policy insights for advancing the coordinated development of regional digital transformation and green low-carbon initiatives.
基金Key Project of National Social Science Fund,No.23AZD032National Natural Science Foundation of China No.42371258Program of China Scholarship Council No.202306850036。
文摘Low-carbon urban development in China can pave the way to achieve the dualcarbon goal.Exploring how land use changes(LUCs)impact carbon storage(CS)under multi-climate scenarios in different urban agglomerations helps to formulate differential scientific carbon mitigation policies.In this regard,this study constructs an integrated model of SD-PLUS-InVEST to simulate LUCs and CS changes under multi-climate change-based scenarios(SSP126,SSP245,SSP585)for three major urban agglomerations(3UAs)in the Yangtze River Economic Belt.Results demonstrate that land use demand in the 3UAs changes considerably in each scenario.Construction land in the 3UAs remains the most important growth category for the coming decade,but its increase varies in different scenarios.CS in the Yangtze River Delta Urban Agglomeration(YRDUA)and Mid-Yangtze River Urban Agglomeration(MYRUA)shows a similar downward trend under different scenarios,with scenario SSP245 decreasing the most,to 184,713.526 Tg and 384,459.729 Tg,respectively.CS in the Cheng-Yu(Chengdu-Chongqing)Urban Agglomeration(CYUA)exhibits the opposite upward trend,with scenario SSP126 increasing the most to 153,007.973 Tg.The major cause of CS loss remains the conversion of forest land to construction land in the YRDUA and MYRUA under different scenarios.However,in the CYUA,the conversion of forest land to cultivated land is the major driver of CS loss under scenario SSP126.In contrast,the conversion of cultivated land to construction land dominantly drives CS loss under scenarios SSP245 and SSP585.The conversion of water body to other land use types is the major cause of CS gain in the YRDUA and MYRUA under different scenarios.At the same time,in the CYUA,the driver is the conversion of cultivated land to forest land.These findings demonstrate the significance of the low-carbon development in urban agglomerations at different development stages at home and abroad.
基金National Natural Science Foundation of China,No.42330106。
文摘Dryland regions face complex interactions between urbanization and ecological changes,where effective coordination is essential for enhancing sustainability and resilience.However,most studies concentrate on the national or provincial scales,with insufficient research on county-level coordination,limiting the ability to provide targeted polifrom a precise perspective.This study addresses this gap by analyzing 39 counties within the Hohhot-Baotou-Ordos-Yulin Urban Agglomeration(HBOYUA),a typical dryland urban cluster in China.We use daytime and nighttime remote sensing images to track the spatio-temporal evolution of urbanization and ecological conditions from 1992 to 2023.A novel quantitative framework based on an improved coupling coordination degree(CCD)is proposed to assess their coordination relationship.The results reveal that:(1)Urbanization and ecological quality both exhibited fluctuating upward trends,with spatial heterogeneity increasing for urbanization and decreasing for the eco-environment.Regions with better ecological conditions had higher urbanization levels.(2)The overall coordinated level improved from imbalance(0.36)to low-level coordination(0.55),although its spatial distribution remained uneven,with central urban areas showing higher CCD than surrounding counties.(3)Socioeconomic factors exerted greater effects on CCD than natural factors,with GDP and land surface temperature(LST)playing a significant role in interaction analysis.(4)In western arid regions,urbanization did not necessarily harm ecosystems;instead,ecological conditions improved alongside urbanization.This research offers targeted and valuable references for county and city governments in resource allocation and sustainable development.The proposed methodology is also adaptable for urban resilience studies in other regions.
基金National Natural Science Foundation of China,No.42171216,No.71733001Key R&D Program of Beijing Municipal Education Commission,No.KZ202210038047Tsinghua University Initiative Scientific Research Program,No.2022THZWJC15。
文摘Research on urban health constitutes an important issue in the field of health geography and also a strong propeller of the Healthy China Initiative.As the main form that realizes new-type urbanization,urban agglomerations should become the primal sites for the construction of a“Healthy China”.The evaluation of healthy cities’development in urban agglomerations has both theoretical and practical values.Based on the concept of urban health and its evaluation models,this paper developed an evaluation framework for healthy cities that involved multiple data sources.With 19 urban agglomerations in China as the research subjects,we used CRITIC weighting and geographical detectors to examine the geographies of healthy cities and their influencing factors in 2010 and 2020.The results were fourfold.Firstly,the urban health level of China significantly increased from 2010 to 2020,and the comprehensive health index developed towards a positive skewed distribution,along with a shift from“low in the hinterland-high in the coastal areas”to a“multipolar”pattern led by the coastal and southwest urban agglomerations.Secondly,among various dimensions of urban health,the healthy environment index became improved with narrowed regional differences;while the health services index was still polarized;health collaboration was upgraded with a strengthened intercity health network;the healthy population index slightly declined and converged to the middle.Thirdly,urban health in China has initially demonstrated the characteristics of a H-H pattern in the Yangtze River Delta and ChengduChongqing regions,as well as L-L clusters in the northern urban agglomerations,the narrowed regional differences,and increasing coordination within each urban agglomeration.Fourthly,the geographical detector found that economy,urbanization and the human capital were significant external factors that affected urban health development.The explanatory power of technological innovation and opening to the outside world were also increasing.The development of healthy cities is yet to be transformed into regional health integration.
基金supported by National Natural Science Foundation of China(grant nos.42101124,W2412136)International ResearchCenter of BigData for SustainableDevelopmentGoals(grant no.CBAS2022GSP02)Nanjing University Integrated Research Platform of the Ministry of Education—Top Talents Program.
文摘Green space plays an important role in the sustainable urban development.This study proposes the Green Lighting Index(GLI),integrating nighttime light data from SDGSAT-1 and theNormalized DifferenceVegetation Index(NDVI)from Sentinel-2,to explore the nighttime human activity in green spaces across three major urban agglomerations in China:Beijing-Tianjin-Hebei(BTH),the Yangtze River Delta(YRD),and the Greater Bay Area(GBA).The findings reveal that,for most green spaces,the relationship between nighttime lighting and green spaces is predominantly exclusionary.However,a synergistic relationship is observed in some vibrant green spaces characterized by abundant nighttime lighting.This synergy is evident in high GLI levels,which are strongly positively correlated with per capita Gross Domestic Product(GDP).This research underscores the importance of integrating nighttime perspectives into green space studies.We believe GLI could be used in the assessment of green space quality and contribute to the development of sustainable cities.
基金funded by the Xi'an Social Science Fund(24QL38).
文摘Studying the spatiotemporal variation and driving mechanisms of vegetation net primary productivity(NPP)in the Guanzhong Plain Urban Agglomeration(GPUA)of China is highly important for regional green and low-carbon development.This study used the Theil-Sen trend analysis,Mann-Kendall trend test,coefficient of variation,Hurst index,and machine learning method(eXtreme Gradient Boosting and SHapley Additive exPlanations(XGBoost-SHAP))to analyze the spatiotemporal variation of NPP in the GPUA from 2001 to 2020 and reveal its response to climate change and human activities.The results found that during 2001-2020,the averageNPP in the GPUA showed a significant upward trend,with an annual growth rate of 10.84 g C/(m^(2)•a).The multi-year average NPP in the GPUA was 484.83 g C/(m^(2)•a),with higher values in the southwestern Qinling Mountains and lower values in the central and northeastern cropland and built-up areas.The average coefficient of variation of NPP in the GPUA was 0.14,indicating a relatively stable state overall,but 72.72%of the study area showed weak anti-persistence,suggesting that NPP in most areas may have declined in the short term.According to XGBoost-SHAP analyses,elevation,land use type and precipitation were identified as the main driving factors of NPP.Appropriate precipitation and higher temperatures promote NPP growth,whereas extreme climates,high population density,and nighttime lighting inhibit NPP.This study has important theoretical and practical significance for achieving regional sustainable development,offers a scientific basis for formulating effective ecological protection and restoration strategies,and promotes green,coordinated,and sustainable development in the GPUA.
基金Under the auspices of the National Social Science Foundation of China(No.23BJL133)。
文摘Taking 18 large-scale urban agglomerations(UAs)in China as the research objects,this study analyzes the characteristics of the spatiotemporal patterns of carbon emissions in UA areas in China and their impact mechanisms by citing Moran’s I and geographically weighted regression(GWR).The research findings are as follows:1)obvious differences are found in carbon emissions among different UAs.The cities with higher absolute carbon emissions are mainly distributed in the major cities of the Hohhot-Baotou-Ordos-Yulin UA.2)From 2011 to 2021,the carbon emission levels of China’s UAs grew obviously,but the spatial differences are pronounced,among which the Hohhot-Baotou-Ordos-Yulin UA and others had the highest growth rates.The carbon emission patterns of UAs also present obvious spatial clustering characteristics.The regions with the most obvious growth rates of carbon emissions at the urban scale are mainly distributed in the Hohhot-Baotou-Ordos-Yulin UA and Mid-Yangtze River UA.3)The value of secondary industry(X_(vsi)),number of urban enterprises(X_(nue)),public library holdings(X_(plh)),and urban passenger volume(X_(upv))have an obvious effect on carbon emissions.However,the regression cofficients exhibit obvious spatial variation.Among them,X_(vsi) has an obvious positive effect on carbon emissions,indicating that spatial agglomeration of the real economy substantially increases reginal carbon emission levels.The high X_(nue)regression coefficients are mainly distributed in Harbin-Changchun UA,indicating that the growth of enterprises in this region is still dominated by traditional high-carbon-emission enterprises,the urgent task of low-carbon transformation and upgrading for traditional industries in old industrial regions.The regression coefficients of X_(plh)and X_(upv) are generally negative,suggesting that improving public service facilities and strengthening regional transportation links can help to reduce the level of carbon emissions.
基金supported by the Sichuan Science and Technology Program(Grant No.2023NSFSC0250).
文摘Exploring the spatiotemporal changes in Fractional Vegetation Coverage(FVC)helps to more accurately understand the quality of the ecological environment,which is of great significance for regional ecological protection and sustainable economic development.The study takes the Chengdu-Chongqing urban agglomeration as the research area,analyzes the characteristics and trends of vegetation cover changes from 2000 to 2020 using the Google Earth Engine cloud platform,and explores its driving factors based on the enhanced regression tree model.The results show that:(1)From 2000 to 2020,the annual FVC of the Chengdu-Chongqing urban agglomeration showed a fluctuating upward trend,with a stable phase from 2000 to 2003 and an upward phase from 2003 to 2020.(2)During the research period,most areas within the agglomeration exhibited negligible changes in FVC.In contrast,other areas showed a complex pattern of both vegetation degradation and improvement.The areas with improved FVC were sporadically distributed,accounting for 15.08% of the total area,whereas areas with substantial vegetation degradation constituted 11.60%.(3)The FVC in the Chengdu-Chongqing urban agglomeration is predominantly influenced by four key factors:population dynamics,forestrymanagement practices,annual sunshine duration,and annual precipitation.Collectively,these factors account for 99.31%of the variation in FVC,with anthropogenic factors(population dynamics and forestry management)exerting the most significant influence.
基金Under the auspices of National Natural Science Foundation of China(No.42271214)Key Research Program of Gansu Province(No.23ZDKA0004)Natural Science Foundation of Gansu Province(No.25JRRA212,21JR7RA281,22JR11RA149,24JRR A250)。
文摘Due to the multiple impacts of global climate change and anthropogenic disturbances,regional ecological landscapes have been developing towards fragmentation.How to quantitatively measure regional ecological landscape fragmentation and identify its key drivers is an important foundation for regional biodiversity conservation and ecosystem restoration.Taking the Guanzhong Plain Urban Agglomeration(GPUA),China as the research object,this paper proposes a comprehensive framework that integrates landscape pattern index,principal component analysis,random forest(RF)and other methods to quantitatively analyze the spatial and temporal evolution of ecological landscape fragmentation and its driving factors.The results show that:1)cropland,forestland and grassland showed significant spatial differentiation in the landscape pattern index,and the change of their mean values indicated that cropland and forestland show a trend of‘little decrease-continuous increase’.Spatially,the northwestern and southeastern regions showed significant fragmentation and prominent spatial heterogeneity.2)From 2010 to 2020,the landscape fragmentation of cropland and forestland increased by 71%and 20%,respectively,while that of grassland decreased by 33%,indicating that the degree of landscape fragmentation of cropland changed more drastically than that of other ecological land.3)It was found that slope was the most important factor affecting landscape fragmentation of ecological land.In addition,road density had a significant effect on landscape fragmentation of cropland and forestland,but the min-distance between patches and the county center had an important effect on landscape fragmentation of grassland.This study can provide theoretical references for urban agglomeration planning and sustainable landscape management on a regional scale.
基金National Natural Science Foundation of China,No.42461012Yunnan Fundamental Research Projects,No.202201AU070064。
文摘Understanding the evolutionary trends and driving factors behind extreme hourly precipitation(EHP)in typical urban agglomerations is crucial for predicting and preventing rapid floods.We collected hourly precipitation datasets from 31 observation stations in the Central Yunnan Urban Agglomeration(CYA)spanning from 2004 to 2020.Urban and rural observations were dynamically classified based on impervious surface fraction.Linear(Granger)and nonlinear causal methods(convergent cross-mapping and Liang–Kleeman information flow)were used to identify the causal impact mechanisms of large-scale circulation,environment and urbanization on EHP.Moreover,geo-detector further reveals the spatial influence of these factors and their interactions on EHP.Our findings revealed that EHP mainly occurred in the afternoon and at midnight.Also,the frequency and intensity of EHP in the CYA significantly(p≤0.05)increased from 2004 to 2020,especially in urban areas.The increasing rate in urban areas was higher than that in rural areas.However,the duration of EHP/hourly total precipitation exhibited a significant/nonsignificant decreasing trend with no significant difference between urban and rural areas.Causality tests and geo-detector indicated that EHP was impacted by natural variability and urbanization.Large-scale circulation indices such as the Pacific Decadal Oscillation,El Ni?o-Southern Oscillation,and Indian Ocean Dipole nonlinearly influenced EHP.Additionally,urban landscape layout,vegetation,and population variation may strengthen EHP by changing environmental factors such as temperature and relative humidity.Interactions exist between these factors and influence EHP,although large-scale circulation remains the dominant influence.With global climate warming and rapid urbanization in the CYA,the frequency and intensity of EHP may further amplify in the future.
基金Under the auspices of National Natural Science Foundation of China(No.U21A2022,U1901219,42101369)National Key Research and Development Program of China(No.2023YFF0807204)。
文摘Wetlands offer important ecological functions and values.Wetland functional zoning provides a reference and basis for sustainable fulfilment and management.In this study,two coastal urban agglomerations in South China were taken as study areas,namely,the Guangxi Beibu Gulf(GBG)and Guangdong-Hong Kong-Macao Greater Bay Area(GBA).Based on multisource information data,a wetland functional zoning system was constructed with the four levels of zoning concept,zoning principle,zoning basis,and zoning scheme.The functional zoning and dynamic analysis of wetlands from 1990 to 2020 were carried out from multiple perspectives of wetland ecological functions,wetland management and conservation functions.The results showed that:1)in terms of wetland ecological functions,the two coastal urban agglomerations were dominated by hydrological regulation and purification of environmental functional areas.The coastal region was largely characterized by the main functional areas of climate regulation and biodiversity maintenance.2)Regarding wetland management and conservation functions,two coastal urban agglomerations exhibited similar trends in terms of the sizes of their conservation and buffer zones from 1990 to 2020.Prevention and control zones were mainly located in core cities in a concentrated manner.Conservation zones largely comprised mountainous woodlands and important wetlands.3)The two coastal urban agglomerations could be divided into 21 wetland functional zones.The central river area has remained the main prevention and control zone for many years.Regarding conservation zones,ecological protection and restoration should be the main focus.Regarding buffer zones,the construction of wetlands and surrounding complex systems should be strengthened or enhanced.Regarding prevention and control zones,activities that do not affect wetland functions should be allowed,provided that they comply with existing laws and regulations.This study could provide technical support and practical application guidance for wetland regulation and management.
基金Major Program of National Fund of Philosophy and Social Science of China(24&ZD148).
文摘China is one of the countries with the longest history in the world.The protection and development of historical and cultural resources is an issue worthy of attention in the fields of economic geography and urban-rural planning at the present stage.This study takes the Zhongyuan Urban Agglomeration,which is rich in historical and cultural heritage,as a specific case,analyzes the characteristics of the spatial-temporal distribution pattern of its historical and cultural resources.The results show that the distribution structure of historical and cultural element resources within the Zhongyuan Urban Agglomeration presents significant regional agglomeration and combination characteristics.In response to the analysis results,the study formulates an optimization strategy for the regional development pattern supported by the protection and development of historical and cultural resources,and initially proposes a matching spatial development pattern plan and policy recommendations for coordinated development.
基金funded by the National Natural Science Foundation of China(Grants No.42071225 and 42471243)the Natural Science Foundation of Hunan Province(Grant No.2020JJ4056)the Postgraduate Scientific Research Innovation Project of Hunan Province(Grant No.QL20230126).
文摘Promoting positive urban–rural interactions is a key strategy for addressing rural decline and advancing regional sustainable development.This study examines the impacts of urban–rural interactions on rural development and explores their mechanisms for advancing sustainability within urban agglomeration areas.Using the Chang–Zhu–Tan(CZT)urban agglomeration as a case study,with an indicator system to measure urban–rural interactions and rural sustainable development,we analyze the mediating effects of resource flows in the process of urban–rural interactions driving rural sustainability through a mediation model.The results show that spatial connectivity,industrial convergence,and social integration between urban and rural areas positively contribute to the economic and social sustainability of rural areas.However,urban–rural spatial connectivity and social integration may negatively impact on rural environment.In this process,capital,technology,and labor play significant mediating roles,whereas the influence of land is less pronounced.Based on these findings,we propose several recommendations for strategically leveraging the benefits of urban–rural interactions across various social-ecological contexts while mitigating their drawbacks.
基金Under the auspices of Chinese National Funding of Social Sciences (No.17AGL005)Institute of Socialism with Chinese Characteristics of Southeast University (No.DDZTZK2021C11)。
文摘This study constructs a quasi-natural experiment based on the expansion of the Yangtze River Delta urban agglomeration(YRDUA) of China in 2010 to investigate the impact and inner mechanism of urban agglomeration expansion on fine particulate matter(PM_(2.5)) concentrations through propensity scores in difference-in-differences models(PSM-DID) using panel data from 286 prefecturelevel cities in China from 2003 to 2016. The results show that 1) urban agglomeration expansion contributes to an overall decrease in PM_(2.5)concentration, which is mainly achieved from the original cities. For the new cities, on the other hand, the expansion significantly increases the local PM_(2.5)concentration. 2) In the long term, the significant influence of urban agglomeration expansion on PM_(2.5)concentration lasts for three years and gradually decreases. A series of robustness tests confirm the applicability of the PSM-DID model.3) Cities with weaker government regulation, a better educated population and higher per capita income present stronger PM_(2.5)reduction effects. 4) Urban agglomeration expansion affects the PM_(2.5)concentration mainly through industrial transfer and population migration, which cause a decrease in the PM_(2.5)concentration in the original cities and an increase in the PM_(2.5)concentration in the new cities.Corresponding policy suggestions are proposed based on the conclusions.
文摘The inter-city linkage heat data provided by Baidu Migration is employed as a characterization of inter-city linkages in order to facilitate the study of the network linkage characteristics and hierarchical structure of urban agglomeration in the Greater Bay Area through the use of social network analysis method.This is the inaugural application of big data based on location services in the study of urban agglomeration network structure,which represents a novel research perspective on this topic.The study reveals that the density of network linkages in the Greater Bay Area urban agglomeration has reached 100%,indicating a mature network-like spatial structure.This structure has given rise to three distinct communities:Shenzhen-Dongguan-Huizhou,Guangzhou-Foshan-Zhaoqing,and Zhuhai-Zhongshan-Jiangmen.Additionally,cities within the Greater Bay Area urban agglomeration play different roles,suggesting that varying development strategies may be necessary to achieve staggered development.The study demonstrates that large datasets represented by LBS can offer novel insights and methodologies for the examination of urban agglomeration network structures,contingent on the appropriate mining and processing of the data.
基金National Natural Science Foundation of China, No.41371177, No.71433008 National Social Science Foundation of China, No. 13＆ZD027
文摘Urban agglomerations are an inevitable outcome of China＇s new national industrialization and urbanization reaching relatively advanced stages of development over the past 30 years. In the early 2000 s, urban agglomerations became new geographical units for participating in global competition and the international division of labor, and China has spent the past decade promoting them as the main spaces for pushing forward its new form of urbanization. The convening of the first Central Work Conference on Urbanization and the National New-type Urbanization Plan（2014–2020） further defined the status of urban agglomerations as the main players in promoting China＇s new type of national urbanization. Nevertheless, urban agglomerations remain a weak link in Chinese academia and are in urgent need of study. Only 19 articles on the theme of urban agglomerations were published in the journal Acta Geographica Sinica between 1934 and 2013, accounting for only 0.55% of all articles written during that period. Not only are there very few, they have also all been published within a relatively short period of time, with the first having been published only 10 years ago. The studies are also concentrated among only a few authors and institutions, and research is aimed at national requirements but is rather divergent. Even so, some studies on urban agglomerations have played a leading role and made important contributions to dictating the overall formation of urban agglomerations nationwide. Specifically, a proposed spatial pattern for urban agglomerations formed the basic framework for the spatial structure of China＇s urban agglomerations and guided the government to make urban agglomerations the main urban pattern when promoting the new type of urbanization; proposed standards and technologies for identifying the spatial dimensions of urban agglomerations played an important role in defining the scope of national urban agglomerations; a series of studies in the area of urban agglomerations spurred more in-depth and practical studies in the field; and studies on issues related to the formation and growth of urban agglomerations provided warnings on the future selection and development of urban agglomerations. Taking the progress and results of these studies as a foundation, the foci of selecting and developing urban agglomerations in China are as follows： to be problem-oriented and profoundly reflect on and review new problems exposed in the selection and development of urban agglomerations; to concentrate on urban agglomerations and lay importance on the formation of a new “5＋9＋6” spatial structure for China＇s urban agglomerations; to rely on urban agglomerations and promote the formation of a new pattern of national urbanization along the main axes highlighted by urban agglom-erations; to be guided by national strategic demand and continue to deepen understanding of major scientific issues in the course of the formation and development of urban agglomerations, including studying the resource and environmental effects of high-density urban agglomerations, scientifically examining resource and environmental carrying capacities of high-density urban agglomerations, creating new management systems and government coordination mechanisms for the formation and development of urban agglomerations, studying the establishment of public finance systems and public finance reserve mechanisms for urban agglomerations, and studying and formulating technical specifications for urban agglomeration planning and standards for delineating urban agglomeration boundaries.
基金National Natural Science Foundation of China, No.41371182 Key Project of Hunan Social Science Foundation, No. 12ZDB01 Entrusting Project of Hunan Social Science Foundation Base, No. 12JD 12
文摘Due to its great strategic significance in integrating regional coordinated development and enhancing the rise of Central China, urban agglomeration in the middle reaches of Changjiang （Yangtze） River has attracted much attention from both theoretical and practical aspects. Such research into the area＇s economic network structure is beneficial for the formation of an urban- and regional-development strategy. This paper constructs an economic tie model based on a modified gravitation model. Subsequently, referring to social network analysis, the paper empirically studies the network density, network centrality, subgroups and structural holes of the middle reaches of Changjiang River＇s urban agglomeration economic network. The findings are fourfold： （1） an economic network of urban agglomeration in the middle reaches of Changjiang River has been formed, and economic ties between the cities in this network are comparatively dense; （2） the urban agglomeration in the middle reaches of Changjiang River can be divided into four significant subgroups, with each subgroup having its own obvious economic communications, while there is less economic-behavioral heterogeneity among subgroups - this is especially true for the two subgroups that exist in the Poyang Lake Ecological Economic Zone; （3） an economy pattern driven by the central cities of Wuhan, Changsha and Nanchang has emerged in the urban agglomeration of the middle reaches of Changjiang River, while these three capital cities have exerted great radiation abilities to their surrounding cities, the latter are less able to absorb resources from the former （4） the Wuhan Metropolitan Areas and the Poyang Lake Ecological Economic Zone have more structural holes than the Ring of Changsha, Zhuzhou and the Xiangtan City Clusters, meaning that cities at the periphery of these two areas are easily constrained by central cities. The Ring of Changsha, Zhuzhou and the Xiangtan City Clusters have fewer structural holes; thus, the cities in this area will not face as many constraints as those in the other two areas.
