Spatiotemporal characteristics and driving forces of construction land expansion in Yangtze River economic belt, China

Future carbon storages of ecosystem based on land use change and carbon sequestration practices in a large economic belt

Assessments of ecosystem carbon storage are needed to form the scientific basis for carbon policies. Due to lack of data, there are few accurate, large-scale, and long-term predictions of ecosystem carbon storage. This study used the Distributed Land-Use Change Prediction (DLUCP) model with ten socioeconomic and two climate change scenarios for a total of 20 combinations that take into account population increase, technology innovation, climate change, and Grain for Green Project to make high-resolution predictions of land use change in the Yangtze River Economic Belt. Low and high carbon sequestration practices were considered to predict future carbon densities. Land use change data, carbon densities data, and the InVEST model were used to predict changes in ecosystem carbon storage from now to 2070. The results show a slight increase (1.88-4.17%) in carbon storage in the study area only based on land use change. Grain for Green Project has the largest impact on carbon storage among population increase, technology innovation, climate scenarios, and Grain for Green Project, which increases carbon storage by 4.17%. After the implementation of carbon sequestration practices, there is an increase in carbon storages from 28.51 to 56.77% in the study area from now to 2070, and increasing carbon storages of forest in each stream and carbon storage of cropland in downstream are efficient ways to achieve carbon neutralization.

Impact assessment of urbanization on vegetation net primary productivity: A case study of the core development area in central plains urban agglomeration, China

Rapid urbanization process has a negative or positive impact on vegetation growth. Net primary productivity (NPP) is an effective indicator to characterize vegetation growth status. Taking the core development area of the Central Plains urban agglomeration as the study area, we estimated the NPP and its change trend in the past four decades using the Carnegie-Ames-Stanford Approach (CASA) model and statistical analysis based on meteorological and multi-source remote sensing data. Meanwhile, combined with the urbanization impact framework, we further analyzed urbanization's direct and indirect impact on NPP. The results showed that the urban area increased by 2688 km² during a high-speed urbanization process from 1983 to 2019. As a result of the intense urbanization process, a continuous NPP decrease (direct impact) can be seen, which aggravated along with the acceleration of the urban expansion, and the mean value of direct impact was 130.84 g C·m^-2·a^-1. Meanwhile, urbanization also had a positive impact on NPP (indirect impact). The indirect impact showed an increasing trend during urbanization with a mean value of 10.91 g C·m^-2·a^-1. The indirect impact was mainly related to temperature in climatic factors. The indirect impact has a seasonal heterogeneity, and high-temperature environments of urban areas are more effective in promoting vegetation growth in autumn and winter than in summer. Among different cities, high-speed development cities have higher indirect impact values than medium's and low's because of better ecological construction. This study is of great significance for understanding the impact of urbanization on vegetation growth in the Central Plains urban agglomeration area, supporting urban greening plans, and building sustainable and resilient urban agglomerations.

Analyzing the Spatio-Temporal Dynamics of Urban Land Use Expansion and Its Influencing Factors in Zhejiang Province, China

The 21st century expansion of built-up areas due to rapid urbanization has recently been at the forefront of global land use/land cover research. Knowledge of the changing dynamics of urban land use is crucial for the monitoring of urbanization and the promotion of sustainable urban development. In this paper, Zhejiang Province was selected as the study area. It is a region with rapid urban growth located along the southeastern coast of China, with a highly developed economy but with a shortage of land resources. We employed remotely sensed and socio-economic panel data for the period between 1990 and 2020 to monitor urban land use changes and utilized the spatial Durbin model (SDM) to examine the urbanization process and the various driving factors of rapid urban expansion in Zhejiang Province, China, from 1990 to 2020. The study's results revealed substantial urban growth of about 6899.59 km², i.e., 6.6%, whereas agricultural land decreased by 4320.68 km², i.e., 4.19%. The rapid urban development was primarily attributed to the transformation of farmlands, forestlands, and water bodies into built-up areas by nearly 86.9%, 6.94%, and 6.06%, respectively. The built-up areas revealed features of spatial clustering. The study showed that the expansion hotspots were mainly distributed within the urban fabric of cities such as Hangzhou, Ningbo, Jinhua-Yiwu, and Wenzhou-Taizhou. The results further revealed the substantial influence of urban growth on the local areas of the province. As the core explanatory variables, population and economic development significantly promoted local urban expansion. The study's findings indicated a positive spatial spillover effect as regards the influence of economic development on the study area's urban growth, whereas the spatial spillover effect of the population was negative. Therefore, economic development was a major driving factor contributing immensely to the expansion of urban areas in Zhejiang Province, especially in the 26 mountainous counties of the province. The study enriches our understanding of the transformation of LULC and the changing dynamics of urban areas in China and provides the necessary research data that are vital for urban land-use planners and decision-makers to overcome the negative consequences of the expansion of urban areas due to the continuous economic growth of China.

Construction Land Expansion of Resource-Based Cities in China: Spatiotemporal Characteristics and Driving Factors

Studying construction land expansion (CLE) characteristics and driving factors in resource-based cities (RBCs) is important to promote efficient land use and maintain ecological equilibrium in RBCs. This study explores the CLE and its driving factors in RBCs. The results indicated that (1) the CLE in RBCs became increasingly obvious, and the number of cities with expansion areas exceeding 20 km² increased from 29 to 86. In RBCs in different regions, CLE in eastern, central, and western regions was obvious, while CLE in the northeast region decelerated. The order of CLE degree at different stages of RBCs was mature, growing, regenerative, and declining. (2) Single factors such as gross domestic product, fixed-asset investment, and secondary industry added value, playing a major role. This differs from the dominant role of population and urbanization in existing research. This occurred because population growth is slow, the urbanization rate is low, population contraction prominently occurs, and economic development exhibits notable path dependence in RBCs. (3) Interaction-factor detection demonstrated that the force of two-factor interaction was greater than that of a single factor, and the interactions of total population with fixed-asset investment and economic development level strongly drove CLE in RBCs.

Identifying driving factors of urban land expansion using Google Earth Engine and machine-learning approaches in Mentougou District, China

The research on driving mechanisms of urban land expansion is hot topic of land science. However, the relative importance of anthropogenic-natural factors and how they affect urban land expansion change are still unclear. Based on the Google Earth Engine platform, this study used the support vector machine classifier to extract land-use datasets of Mentougou district of Beijing, China from 1990 to 2016. Supported by machine-learning approaches, multiple linear regression (MLR) and random forests (RF) were applied and compared to identify the influential factors and their relative importance on urban land expansion. The results show: There was a continuous growth in urban land expansion from 1990 to 2016, the increased area reached 6097.42 ha with an average annual rate of 8.01% and average annual intensity rate of 2.57%, respectively. Factors such as elevation, risk of goaf collapse, accessibility, local fiscal expenditure, industrial restructuring, per capita income in rural area, GDP were important drivers of urban land expansion change. The model comparison indicated that RF had greater ability than MLR to identify the non-linear relationships between urban land expansion and explanatory variables. The influencing factors of urban land expansion should be comprehensively considered to regulate new land policy actions in Mentougou.

Spatial Differentiation and Driving Factor Analysis of Urban Construction Land Change in County-Level City of Guangxi, China

The change of urban construction land is most obvious and intuitive in the change of global land use in the new era. The supply and allocation of construction land is an important policy tool for the government to carry out macro-control and spatial governance, which has received widespread attention from political circles, academia, and the public. An empirical study on the change of construction land and its driving factors in 70 county-level cities in Guangxi, China based on the GeoDetector method reveals the driving mechanism of the construction land change in county-level cities and provides more detailed information and a more accurate basis for county-level city policy makers and decision makers. The study shows a significant heterogeneity in the action intensity and interaction between construction land change and its driving factors in county-level cities, where population and GDP size, transportation, and industrial structure are determining factors. Besides, the factors of fiscal revenue, social consumption, utility investment, and real economy have a very weak action force individually, but they can achieve significant synergistic enhancement effects when coupled with other factors. In the end, urban construction land change at different scales and their driving mechanisms are somewhat different, and it is recommended to design differentiated and precise construction land control and spatial governance policies according to local conditions.

Land-Use Conflict Identification from the Perspective of Construction Space Expansion: An Evaluation Method Based on ‘Likelihood-Exposure-Consequence’

Land-use conflict (LUC) is a major problem of land management in the context of rapid urbanization. Conflict identification plays an important role in the development and protection of land space. Considering the possibility of, exposure to, and negative impacts of LUC, we explore the probability of land-use cover change (LUCC), policy constraints, and ecosystem service value (ESV) and build a conflict identification model based on the LEC concept of risk assessment. Taking Daye City as an example, we classify the conflict intensity and delimit the key conflict areas. At the same time, a composite classification system is constructed to analyze the spatial characteristics and internal mechanism of conflict. We find that the conflict between construction and ecological space is the main conflict in Daye City (P.R. China), which is widely distributed. However, the conflict between construction and agricultural space, which is mainly distributed near the center of Daye City, cannot be ignored.

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

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

An improved sequential auction with complementarity for pricing the construction land quota

The paradox between idle homesteads in rural areas and the shortage of construction land in urban areas is concerning. Hence, local governments encourage farmers to reclaim their idle homesteads and farmlands to generate quota. However, the current quota price, which is based on the land reclamation cost, is often inadequate to motivate farmers. This study proposed that the construction land quota and construction land are complementary items, and hence, their pricing should be studied simultaneously instead of independently. Therefore, the classical sequential auction model with complementarity was improved using the core characteristics of quota transactions and those were applied to design optimal pricing mechanisms. Subsequently, the influence of relevant factors on the bidding price was analysed. The results indicated that the bidding price decreases with an increase in the number of bidders and that a bidder’s revenue is at a loss when they acquire the quota but fail to obtain the land; hence, the revenue probability is lost. However, bidding prices increase when the fine of delaying construction increases. To raise the quota price and encourage relatively more farmers to reclaim their idle homesteads, local governments should appropriately increase the delaying construction fines or repurchase the quota at a premium from the bidder who acquires the quota but fails to obtain the land, which is beneficial for easing conflict between construction land demands and farmland protection and for promoting the sustainable development of China’s social economy.

Spatial differences of ecosystem services and their driving factors: A comparation analysis among three urban agglomerations in China's Yangtze River Economic Belt

Understanding the spatial distribution characteristics of ecosystem service value (ESV) and their underlying driving factors is critical for ecosystem service management. Using three national-level urban agglomerations in the Yangtze River Economic Belt, Cheng-Yu (CY), Middle-Reach Yangtze River (MRYR), and Yangtze River Delta (YRD), as a case study, this paper quantifies the ESVs and the spatial distribution characteristics, analyzes the driving factors of ESVs using the stochastic impacts by regression on population, affluence, and technology model (STIRPAT). The results specify that: (1) Over the study period 2009-2016, the total ESV of the three urban agglomerations decreases by 5498.70 million USD. The regulating, supporting, and cultural service decrease by 4607.60, 2648.01, and 1182.25 million USD, respectively, while the provisioning service increases by 2795.15 million USD. (2) ESV in MRYR undergoes the largest reduction of 4269.70 million USD, followed by CY and YRD with 1015.66 and 213.35 million USD from 2009 to 2016. (3) In 2016, among the 70 cities at the prefecture level or above, the cities with high total ESV, per unit area ESV, and per capita EVS are mainly distributed to the areas of the south Yangtze River of MRYR and YRD, MRYR, and MRYR and YRD, respectively. (4) In general, land use and cover, population are the main factors affecting ESVs, followed by economic, social and political factors. Among the three urban agglomerations, population, land use and cover basically have the equally important impacts on ESV in CY; land use and cover, especially the proportion of urban construction land has the greatest impact on ESV in MRYR; population, especially the urbanization rate has the greatest impact in YRD. The comparative analysis of the driving factors of ESVs in different regions is helpful to propose differentiated ecological protection policies and promote the increase of ESV accordingly.