How Does Urban Shrinkage Affect Land Use Efficiency?A Case Study of Shrinking Cities in Northeast China

The effect of urban shrinkage has gradually become a new topic.Theoretically,urban shrinkage may exert great influence on land use efficiency(LUE)through various urban subsystems,but there is currently limited research examining these pathways.Using the Super-SBM-Undesirable model and the Structural Equation Model(SEM),this study calculates the LUE of shrinking cities in Northeast China and simulates the process of urban shrinkage affecting LUE.To quantify the process of urban shrinkage affecting LUE,three mediation variables,namely the economy,public services,and innovation,are used as latent variables to apply SEM.The results show that urban shrinkage will affect LUE through a direct path and indirect paths.In the direct path,urban shrinkage leads to an improvement in LUE.In the indirect paths,the economy and innovation will transmit the negative effect of urban shrinkage on LUE,while public services will reverse this effect.An important contribution of this study is that it quantifies the paths of urban shrinkage affecting LUE,thereby expanding the understanding of urban shrinkage effect and laying a foundation for the sustainable development of shrinking cities.

Urban Land Use Efficiency and Contributing Factors in the Yangtze River Delta Under Increasing Environmental Restrictions in China

Evaluating urban land use efficiency(ULUE) provides insights into the interactions between land use systems and their external environment. Specifically, changes in ULUE are important for monitoring urban transformation in developing countries. In this study, using a traditional input-output index model, we incorporated slack-based measurements and undesirable outputs into a SBM-UN(slack-based measure-undesirable) model to investigate ULUE within the context of increasing environmental restrictions in China. The model was used to estimate the ULUE of 26 cities in the highly developed urban agglomeration of the Yangtze River Delta from 2000 to2018. The average ULUE in the Yangtze River Delta was relatively low compared to that of developed city regions in the European Union(EU) and North America and exhibited a U-shaped curve over the study period. Incorporating undesirable outputs, such as environmental pollution, into the model reduced ULUE by 19.06%. ULUE varied spatially, with the kernel density estimation exhibiting a bimodal distribution. Efficiency decomposition analysis showed that scale efficiency made a greater contribution to ULUE than pure technical efficiency. Based on our findings, recommended approaches to improve ULUE include optimizing factor allocation, reducing undesirable outputs, and increasing the effective output per land unit. The study suggests that ULUE and the SBM-UN model are useful planning tools for sustainable urban development.

Efficiency of Land Utilizationand Urbanization Progress of China

Urbanization is a process that is undergoing all over the world, which will speed up in the forthcoming years, especially in China as the boom of economy. On average, urbanization level is not only depended on the speed, but theefficiency, particularly efficiency of using land resource which affects urbanization directly. This paper provided status quo of land resource utilization efficiency, indictors, methods and factors, and illustrated the reference of well land utilization, aiming at fostering urbanization in China.

Spatial-temporal change in urban agricultural land use efficiency from the perspective of agricultural multi-functionality： A case study of the Xi＇an metropolitan zone

The excessive expansion of urbanized areas has resulted in haphazard land utili- zation, immoderate consumption of superior agricultural land and water resources, significant fragmentation of agricultural landscape, and gradual deterioration of the agro-ecological en- vironment. Combined, these factors cause poor land use efficiency. Under these circum- stances, comprehensively assessing land use efficiency for urban agriculture is a key issue in land use research. Currently, evaluation methods for agricultural land use efficiency narrowly concentrate on aspects of economic input and output. However, urban agro-ecosystems can provide diverse economic, social, and ecological services and functions. In particular, the social and ecological services and functions originating from agricultural land, which have a higher value than economic services, play a significant role in ensuring regional social, eco- logical, and environmental security. However, recent research has rarely taken these benefits into consideration. Therefore, land use value has been greatly underestimated, which has resulted in mishandled and poor land use policies. In this study, we apply Landsat imagery and social and economic statistical data for the Xi＇an metropolitan zone （XMZ） to investigate agricultural multi-functionality. We develop an evaluation framework for urban agricultural land use efficiency and identify agro-ecosystem services and functions as important outputs from agricultural land. The land use efficiency of urban agriculture is then evaluated using ecosystem services models, providing a mechanism for assessing spatial-temporal changes in land use efficiency in the XMZ from 1999 to 2015. Four important conclusions are reached from this analysis. First, the rapid urbanization and agricultural transformation from traditional cereal cultivation to modern urban agriculture has resulted in steadily increasing costs, out- puts, and land use efficiency of urban agriculture. The total output value increased 41% and land use efficiency per hectare increased by 33.13% on average. Second, the spatial patterns of comprehensive output and land use efficiency were dominated by economic outputs from agricultural land. Areas near cities, which are dominated by orchard and arable land, provide more economic functions. These areas support and regulate services due to the transforma- tion from extensive cereal production to intensive modern urban agriculture; therefore, they have higher output value and land use efficiency. In contrast, areas distant from cities, towns, and high traffic roads, namely, remote rural areas, provide more support and regulating ser- vices, but have relatively lower economic function due to inaccessibility tO urban markets and slow agricultural transformation. Therefore, these areas have lower output value and land use efficiency. The spatial change in agricultural output and land use efficiency in urban areas is strongly dependent on the degree of urbanization and agricultural transformation. Third, the total output value and land use efficiency of urban agriculture measured with our approach are much higher than evaluations using traditional methods. However, the spatial patterns measured using the two approaches are in agreement. The evaluation framework integrates ecological services and economic and social functions into a comprehensive output from agricultural land. This approach is more methodical and accurate for evaluating the compre- hensive efficiency of land use based on quantities and spatial scale because they are at the pixel scale. Finally, the evaluation results have important implications for enhancing current agricultural subsidies and even implementing ecological payment policies in China. Most importantly, they can be directly applied to agricultural transformation regulations, decision-making, and guidance for rational land utilization.

Evolution Characteristics of Urban Land Use Efficiency under Environmental Constraints in China

In the context of high-quality economic development and coordinated regional development,this paper measures the urban land use efficiency of 275 prefecture-level cities in China from 2003 to 2016,taking into account the unexpected output(environmental pollution),and explores the temporal and spatial evolution of urban land use efficiency through kernel density estimation and spatial autocorrelation analysis.The results show that:(1)From 2003 to 2016,China’s urban land use efficiency showed an overall fluctuating growth,but it remained at a low level.The mean value of urban land use efficiency has been gradually decreasing in east,west and central regions.(2)In the whole country and the eastern,central and western regions,the regional differences have been increasing,and the efficiency values of the whole country and the east have become polarized.(3)Urban land use efficiency shows a weak spatial positive correlation,but the degree of spatial agglomeration is increasing.High-high agglomeration areas are mostly distributed in the southeastern coastal areas,and extend into the central region,while most of the high-low polarized areas are the capital cities of the central and western regions.The low-high depressed areas are scattered around the high-value accumulation areas,some of which have turned into high-high agglomeration areas during the study period,while the low-low homogeneous areas are mainly distributed in the central,western and northeastern regions.Therefore,it is proposed that strengthening the utilization of urban stock land,strengthening the regional cooperation mechanism,and formulating policies which improve the efficiency of land use are effective ways to promote the intensive and economical use of urban land,as well as regional coordinated development.

Exploring complex urban growth and land use efficiency in China's developed regions:implications for territorial spatial planning

Developed regions in China have experienced rapid urban expansion and have consequently induced a series of challenging environmental issues since its economic reform and opening-up.Taking Zhejiang as a case study area,the present paper explores the complex types of urban growth over the last four decades as well as land use efficiency.Moreover,it discusses the implications of the aforementioned on China national territorial spatial planning(TSP).The acquired results have shown that:1)urban expansion has slowed down,exhibiting a three-stage trend of"slight increase(1980-1990)—dramatic growth(1990-2010)—slow growth(after 2010)";2)the complex types of urban growth reveal that the urban diffusion has been gradually controlled and the urban form tends to be more condensed;and 3)the mean values for pure technical efficiency(PTE)and scale efficiency(SE)of urban land use are 0.83 and 0.95 respectively,indicating PTE as the main factor restricting the improvement of urban land use.Based on these results,some beneficial policy implications and suggestions for TSP are provided.First,it is suggested that"Inventory Planning"will be the main direction of TSP other than"Incremental Planning".Secondly,we should pay more attention to the protection of cultivated land and ecological resources.Lastly,TSP should guide the economic growth away from simply relying on resource inputs and steer it toward technology and capital investment.

Driving Mechanism of Urban Space Expansion in Luoyang, China

Urban space expansion is the result of the interaction between internal and external forces of the urban. Based on the remote sensing image data of 1990, 2000, 2010, and 2020, and the social and economic development data, this paper analyzes the driving mechanism of the Luoyang space expansion characteristics and its correlation characteristics. By using urban land use efficiency index, urban expansion elastic index;urban allometric growth index, and grey correlation analysis in 4 times sections and 3 periods. The research results show that the urban space expansion of Luoyang mainly comes from the needs and support of economic development, the coordination between urban space expansion and population development is poor, and urban space expansion effectively attracts the inflow of external funds, and the settlement of migrants, drives the development of the tertiary industry, and increases the local revenue.

Understanding the change of land space utilization efficiency with different functions and its coupling coordination: A case study of Urban Agglomeration in the Middle Reaches of the Yangtze River, China

Land spaces function in capacities of urban development,agricultural production,and ecological conservation,among many others.Research of land space utilization efficiency(LSUE)and coupling coordination relationships among its subsystems are significant for sustainable land space development.In this study,taking the Urban Agglomeration in the Middle Reaches of the Yangtze River(UAMRYR)as the study area,we establish a measurement index system to evaluate the LSUE(2000–2018)and analyze its coupling coordination degree by utilizing an improved coupling coordination model.The main results include the following.(1)The average efficiency levels of urban space and agricultural space in the UAMRYR increased 2000–2018,while the average efficiency of ecological space declined.(2)The spatial pattern of the LSUE values varied greatly,with the distributions of high-efficiency and low-efficiency levels significantly different.(3)The coupling degree of LSUE includes three types,i.e.,high-level coupling,break-in,and antagonism.Each coupling degree type was characterized by change over time.(4)The proportion of areas with high coupling coordination and moderate coupling coordination increased from 2000 to 2018,while the proportion of areas with basic coupling coordination,moderate imbalance,and serious imbalance declined during this period.Given that the spatial differentiation of the LSUE and its coupling coordination,it is necessary to implement a differential land space development strategy in the UAMRYR.This study is helpful to promote the efficient utilization and coordinated development of land space utilization systems.

长江中游城市群城市土地利用效率的动态演进及空间收敛

探寻碳排放和工业污染物排放双重视域下城市土地利用效率(ULUE)的区域差异及协同提升路径是实现区域可持续发展的根本要求和必然选择。本文以长江中游堿市群2003-2015年数据为研究样本,在考虑城市土地利用碳排放和工业污染物排放对ULUE的双重影响下,构建“规模+结构+效益”的ULUE测度指标体系,并运用随机森林算法、核密度估计及空间收敛模型从时间和空间两个维度对ULUE时序差异的动态演进及空间差异的收敛性进行研究。结果显示:在考虑碳排放和工业污染物排放后,长江中游城市群及其各子城市群ULUE的增长相对缓慢,说明在土地利用过程中ULUE存在双重生态损耗,但ULUE总体上仍不断上升,且基本呈现“南高北低”、“西高东低”的空间非均衡格局。从时间维度上来看,根据核密度估计结果,长江中游城市群及其各子城市群内的ULUE都出现过不同程度的极化现象,但整体上ULUE的地区差距逐渐缩小。其中,长江中游城市群总体、武汉堿市群、环鄱阳湖城市群的ULUE经历了一个先扩大、后缩小的起伏波动过程,地区差异先增加后降低,而环长株潭城市群、江淮城市群ULUE的区域差异呈现先扩大、后趋于稳定的状态。从空间维度上来看,在考虑空间效应的情况下,长江中游城市群内既存在武汉城市群和环长株潭城市群ULUE的绝对β收敛,也存在包括长江中游城市群总体及其子城市群在内的全域范围内ULUE的条件β收敛。为实现环境与ULUE的协调耦合,增强区域绿色化发展能力,提出优化要素空间交流环境、加快实施创新驱动发展战略、严格执行污染排放限制标准等建议。

新能源示范城市建设对城市土地利用效率的影响及其空间溢出效应

研究目的:探究新能源示范城市建设对城市土地利用效率(ULUE)的影响及其空间溢出效应。研究方法:PSMDID、空间计量模型。研究结果:(1)新能源示范城市建设对ULUE的提升作用显著,相较于非试点地区,示范城市的ULUE提升11.2%;(2)新能源示范城市建设在有效提升本地区ULUE的基础上,能够通过空间溢出效应促进邻近区域ULUE的提升;(3)新能源示范城市建设的空间溢出效应存在空间异质性,表现出空间溢出效应从东部到中部再到西部城市依次增强的趋势,且相较于东部城市,中西部城市能够通过示范城市建设获得ULUE的显著提高。研究结论:应促进新能源示范城市试点的有序扩散,因地制宜地设计新能源示范城市发展战略,充分发挥新能源示范城市建设的政策效应,强化试点政策对ULUE的空间溢出效应,实现区域ULUE全面提升。

全球超大城市空间扩张及分形特征

Megacities serve as global centers for economic,cultural,and high-tech industries.The structural features and population agglomerations are typical traits of urbanization,yet little is known about the morphological features and expansion patterns of megacities worldwide.Here we examined the spatiotemporal variations of urban land in megalopolises from 2000 to 2020 using the Urban Expansion Intensity Differentiation Index.The fractal features and expansion patterns of megacities were analyzed using the Area-Radius Multi-dimensional Scaling Model.Urban land use efficiency was then evaluated based on the linear relationship between urban land area and population.We found that Southeast Asia and China were the hotspots of urban expansion in megacities from 2000 to 2020,with urban land areas expanding by 3148.32 km^(2)and 5996.26 km^(2),respectively.The morphological features and expansion patterns of megacities exhibited a growing trend towards intensification and compactness,with the average radial dimension increasing from 1.54 to 1.56.The annual decrease in fractal dimensions indicated the integration of inner urban areas.North America and Europe megacities showed a low urban land use efficiency,with a ratio of urban land area to population ranging from 0.89 to 4.11 in 2020.Conversely,South Asia and Africa megacities exhibited a high urban land use efficiency,with the ratios between 0.23 and 0.87.Our results provide information for promoting efficient urban land utilization and sustainable cities.It is proposed to control the scale of urban expansion and to promote balanced development between inner and outer urban areas for achieving resilient and sustainable urban development.