Effects of internal migrants' health on economic resilience in China's Yangtze River Delta urban agglomeration: moderating effects of basic public health services

Introduction

Internal migrants constitute a significant generality in the socioeconomic development of developing countries. With the frequent occurrence of major public health emergencies, obstacles to labor supply due to health issues among internal migrants not only affect their livelihood stability but also urban economic resilience. Moreover, the design of basic public health service systems tends to favor local residents over internal migrants, further exacerbating the health and employment risks of internal migrants. As a result, urban economic resilience faces significant challenges.

Objective

The objective of this study was to deconstruct economic resilience into economic resistance and recovery abilities, investigate the net effect and its heterogeneity of internal migrants' health on economic resilience in China's Yangtze River Delta urban agglomeration (CYRD), and the mediating effect from labor participation rate and labor time supply, as well as the moderating effect of basic public health services.

Methods

Based on the China Migrants Dynamic Survey data (CMDS), the study empirically estimated the effects of internal migrants' health on economic resilience in CYRD through microeconometric analysis methods, mediating and moderating effect model.

Results

Our findings indicate that internal migrants' health has a positive effect on economic resilience in CYRD. For each unit increase in migrants' health, it will drive up the average economic resistance ability by 0.0186 and the average recovery ability by 0.0039. Secondly, the net effects of migrants' health on economic resilience show significant structural differences, industry and city heterogeneity. The effect of migrants' health on economic resistance ability is significantly higher than that on economic recovery ability; The effect of migrants' health on economic resilience of the secondary industry is higher than that of the tertiary industry; The cities with high economic resistance and recovery abilities have more prominent positive effect from migrants' health. Thirdly, migrants' health not only has a direct effect on the economic resistance and recovery abilities, but also has a mediating effect on which through labor participation rate and labor time supply.

Discussion

Enhancing the accessibility and quality of basic public health services is beneficial for enhancing the positive effects of internal migrants' health on economic resilience.

Effects of production-living-ecological space changes on the ecosystem service value of the Yangtze River Delta urban agglomeration in China

In the process of urbanization, exploring the relationship between production-living-ecological space (PLES) and ecosystem service value (ESV) is a major scientific issue in promoting regional sustainable development. The Yangtze River Delta (YRD) urban agglomeration is an ideal study area, which has the highest urbanization rate in China. Based on Landsat TM/ETM imaging data from 2005, 2010, 2015, and 2018, this study established a land use classification system of PLES. The spatial and temporal characteristics of PLES and ESV were analyzed, and the response of ESV to changes in PLES was investigated based on the elasticity formula. The results showed that from 2005 to 2018, production space and ecological space were the main types of PLES and exhibited an imbalance in transformation. Production space was the main transfer type, and living space significantly expanded. Moreover, from 2005 to 2018, the ESV of the YRD urban agglomeration showed an increasing and then decreasing trend. ESV presented a "high in the southwest and low in the northeast" spatial pattern. Furthermore, ESV was sensitive to changes in PLES, showing a trend of ecological space > production space > living space. However, the sensitivity of ESV to changes in PLES varied according to urbanization level.

Spatiotemporal dynamics of CO2 emissions: a case study of the "New Yangtze River Delta" in China

Due to vast territory and disparate regional energy varieties and efficiency in China, the spatial and temporal distribution of CO₂ emissions in regions is quite different. But the formulation of previous carbon reduction policies was mainly based on national or provincial emissions data, lacking of refined scale data. This paper first collected Defense Meteorological Satellite Program's Operational Linescan System (DMSP/OLS) night light datasets from 1992 to 2013 and constructed a CO₂ emissions inversion estimation model. Then, the spatiotemporal dynamics were analyzed by global and local spatial autocorrelation methods. Findings are as follows: (1) Total CO₂ emissions in the Yangtze River Delta showed an overall growth trend from 396 million tons in 1992 to 1.825 billion tons in 2013, with an average annual growth rate of 17.18%. (2) The relatively slow growth accounted for the highest proportion in five growth types of CO₂ emissions and were mainly concentrated in the underdeveloped southwestern regions of the Yangtze River Delta. The rapid-growth were agglomerated in the eastern coast areas. (3) Hot spots and sub-hot spots were concentrated in Shanghai, Suzhou, and Ningbo. Cold spots and sub-cold spots included southwest part of Anhui and Zhejiang. The findings provided a decision-making basis for mitigating CO₂ emissions more reasonably.

Study on the coupling and coordination degree between urban tourism development and habitat environment in the Yangtze River Delta in China

By constructing the two evaluation systems of urban tourism development (TD) and habitat environment (HE), the dynamic response relationship between the two systems in the Yangtze River Delta urban agglomeration from 2001 to 2020 is explored by using panel vector autoregression (PVAR) model and coupled coordination degree model. The study unearthed four intriguing findings: (1) the level of TD in the study area has been continuously rising from 2001 to 2020, with an initial slow growth rate and then fast. The level of HE is increasing steadily at an average annual rate of 7.05%. There exists a reciprocal response relationship between the two systems, with a strong shock effect in the short term and a synergistic evolution in the long term. (2) The coupling degree between the urban TD and HE has an increasing trend, and the coupling coordination degree of the two systems has an average annual rate of 4.165%, implying the interaction and promotion effect between the two systems is improving. (3) Most of the cities in the Yangtze River Delta gradually realize the evolution from dysfunctional type to coordinated type, but the overall coordination intensity is low. (4) The barrier degrees of TD system indicators show a small annual increasing trend, while the barrier degrees of HE system indicators show a substantial and continuous decreasing trend. In terms of the barrier degree factors, some important factors that restrict the coupled and coordinated development of the two systems are also reported. This research can provide a useful reference for the synergistic improvement of urban tourism economy and habitat environment.

Scarcity Value Assessment of Ecosystem Services Based on Changes in Supply and Demand: A Case Study of the Yangtze River Delta City Cluster, China

Rapid urbanization and economic development have resulted in a mismatch between the supply and demand of ecosystem services. The theoretical value of ecosystem services (ESTV) is not suitable for determining ecosystem service compensation, posing challenges for integrated regional ecological development. A scarcity value model was used to analyze the influence of changes in supply and demand on the scarcity value of ecosystem services (ESSV) in the context of land-use change. The spatio-temporal distribution characteristics and trends of the ESSV from 2010 to 2020 were assessed in the Yangtze River Delta (YRD) urban agglomeration in China, and the driving factors were analyzed to provide theoretical guidance for horizontal ecological compensation across regions. The results show the following: (1) In the scenario that did not consider the impact of supply and demand changes on the scarcity value, the total ESTV decreased by 8.67% from 2010 to 2020, and high-value areas shifted to the west and south, whereas low-value areas shifted to the central and northern region and the Jiangsu, Zhejiang, and Shanghai Ringbelt. The ESTV was low in Shanghai and Jiangsu and high in Zhejiang. (2) In the scenario that considered changes in the supply and demand of ecosystem services, the ESSV increased from RMB 213 million in 2010 to RMB 1.323 billion in 2020; an increase of 521.13%. The scarcity value showed high variability within the provinces, with a larger difference between Zhejiang and Jiangsu and a smaller difference between Anhui and Shanghai. The ESSV was higher in counties with increased urbanization and high population density and lower in counties with slower economic growth and fewer people. (3) Regional ecological integration planning and management should be strengthened, and the ESSV might be considered as the reference standard for ecological compensation. The ESSV showed that spatio-temporal heterogeneity might guide the conversion from ecological resources to ecological capital and promote the regulatory role of market mechanisms to achieve horizontal payments for ecosystem services across regions.

Spatiotemporal pattern of regional carbon emissions and its influencing factors in the Yangtze River Delta urban agglomeration of China

Urbanization is a critical factor affecting regional carbon emissions. Clarifying the linkage between urbanization and carbon emissions can provide a decision-making reference to realize China's goal of carbon neutrality. This article examines the spatiotemporal patterns of urbanization and carbon emissions in the Yangtze River Delta urban agglomeration from 2008 to 2018. A complete set of variables is considered to construct relevant land and ecological urbanization variables, and the Stochastic Impacts by Regression on Population, Affluence, and Technology (STIRPAT) model and spatial Durbin model (SDM) are adopted to explore the impact of various driving factors on carbon emissions. The results indicate that (1) during the study period, the carbon emissions in the Yangtze River Delta urban agglomeration exhibited a fluctuating increase and that the incremental carbon emissions followed a downward trend. (2) Carbon emissions exhibited a positive spatial correlation. Cold- and hotspot areas indicated a three-gradient pattern from west to east, and a concentric circle radiation pattern occurred with Shanghai as the core. Carbon emissions were spatially imbalanced, but the centre of gravity slightly fluctuated, with a total migration distance of 38.48 km, indicating a migration trend towards the southeast. (3) Regarding the two considered dimensions of urbanization, all driving factors except urbanization played a role in carbon emission enhancement. Consequently, for every 1% increase in economic factors, the carbon emissions correspondingly increased by 0.43-0.57%. Hence, economic factors are the most important factors promoting increased carbon emissions. In the ecological urbanization dimension, urbanization caused a non-significant decrease in carbon emissions, while there was no spillover effect on carbon emissions in neighbouring areas. Accordingly, carbon emission reduction efforts should promote the transformation of urbanization from a land-driven process to an ecologically driven process and realize the synergies among carbon emission reductions, urban development, and land use.

The Coupling Synergy Effect of Economic and Environment in Developed Area: An Empirical Study from the Yangtze River Delta Urban Agglomeration in China

Coordination between economic development (ED) and ecological environment (EE) is an important challenge for high-quality urban development. Taking the panel data related to the ED and EE of the Yangtze River Delta urban agglomeration (YUA) from 2009 to 2019 as the research objective, the evaluation system of ED and EE was constructed by introducing the coupling coordination degree model and the gray correlation degree model to analyze their development indices, coupling coordination degree and gray correlation degree in two spatial and temporal dimensions. Research results: (1) The ED indexes and EE indexes of the 26 cities in the YUA have obvious differences in different cities, and there is no synergy between the two indices. (2) The coupling coordination degree of the YUA shows a pattern of high in the east and low in the west, high in the center and low in the north and south in space, and an overall increasing trend in time. (3) In terms of gray correlation, the correlation between ED quality dimension and EE level dimension is the highest. According to the conclusion, when both the economy and environment present consistency at a high level, it will help the city’s economy to develop more efficiently and rapidly.

Spatial spillover effects of urbanization on carbon emissions in the Yangtze River Delta urban agglomeration, China

To achieve a win-win situation for both urbanization and carbon emissions reduction from a spatiotemporal perspective, we need to identify the salient links between urbanization and carbon emissions in different dimensions. Using 2008-2018 panel data on the Yangtze River Delta urban agglomeration, this paper constructs a Stochastic Impacts by Regression on Population, Affluence, and Technology (STIRPAT) model based on four dimensions of urbanization: population, economy, land, and ecology. Additionally, it uses a whole group of variables for reference, constructs a Spatial Durbin model (SDM) to estimate the spatial effect, and empirically investigates the spatial dependence of carbon emissions and the influence of various driving factors. The results show that (1) in the temporal dimension, the historical carbon emissions of the study area continue to increase. However, the extent to which they are doing so is slowing, the number of low carbon emissions areas has significantly decreased, the number of medium carbon emissions areas have significantly increased, the number of high and relatively high carbon emissions areas are relatively stable, and energy intensity continues to decline. (2) In the spatial dimension, Shanghai, Suzhou, and their surrounding cities have always been carbon emissions hotspots, high and relatively high carbon emissions areas are mainly concentrated in these cities. Low carbon emissions areas and cold spots are mainly distributed in Anhui Province. Medium carbon emissions areas show a great spatial and temporal evolution and are distributed in all provinces. (3) In the four dimensions of urbanization, per capita GDP will not only affect regional carbon emissions but also have a spatial spillover effect. For every 1% increase in the economic factors, carbon emissions in neighboring regions will increase by 0.38-0.43%. Population, economic, and technological factors have significant positive effects on carbon emissions, and economic factor is the most important factor. (4) In different dimensions of urbanization, there are obvious heterogeneities in the impacts of different factors on carbon emissions. Among them, the elasticity coefficient of per capita GDP and energy intensity is the smallest among the dimension of land urbanization, and the elasticity coefficient of the total population is the smallest among the dimension of population urbanization. Therefore, when formulating carbon emissions reduction policies, it is necessary to fully consider the spatial spillover effects, determine the optimal population size threshold, advocate for a low-carbon lifestyle, promote clean technology, and realize information exchange and policy interaction across regions from the perspective of holistic governance.

Assessing the Potential Impact of Land Use on Carbon Storage Driven by Economic Growth: A Case Study in Yangtze River Delta Urban Agglomeration

Economic development and land-use change can strongly affect terrestrial ecosystems’ carbon balance. This paper quantifies the changes in land use of Yangtze River Delta urban agglomeration (YRD) in 2020 and 2035 under three economic growth scenarios, exploring the concurrent impact on carbon storage. The results showed that the land carbon storage of YRD had decreased by 1453.80 Tg in 2000–2020, and will continue to decrease by 982.38 Tg, 1417.62 Tg, and 1636.21 Tg under the scenarios of a slow, medium, and rapid economic growth from 2020 to 2035, respectively. The large-scale occupation of cultivated land and woodland for construction land caused by economic development and population growth was an important reason. The occupation of cultivated land by construction land in Nanjing, Shanghai, and its surrounding areas had further intensified, while the reduction in carbon storage caused by the reduction in woodland had become more prominent in Hangzhou, Shaoxing, Jinhua, and the surrounding areas.

Research on Urban Spatial Connection and Network Structure of Urban Agglomeration in Yangtze River Delta-Based on the Perspective of Information Flow

Exploration of urban spatial connections and network structures of urban agglomeration in the Yangtze River Delta, as well as its influencing factors, is of great significance regarding optimization of the development pattern of the Yangtze River Delta urban agglomeration and promotion of regional high-quality development. Therefore, based on Baidu index data in 2015 and 2019, this paper first analyzes the spatiotemporal variation characteristics of information-flow connections in the Yangtze River Delta urban agglomeration. Then it uses social network analysis to explore the information-flow network structure in the Yangtze River Delta urban agglomeration, and finally explores the influencing factors of information-flow intensity in the Yangtze River Delta urban agglomeration. The main conclusions are as follows: (1) The total amount of information flow in the Yangtze River Delta urban agglomeration has had no obvious change, and the coverage of information flow in the central urban circle has expanded. (2) The network hierarchy presents a relatively stable "pyramid" distribution pattern, which tends to develop into a "spindle" pattern. (3) The overall network density of the Yangtze River Delta urban agglomeration is high and is increasing. The backbone network is a "triangle" structure. The central cities in the region are stable, and the subgroups are adjacent to each other geographically. (4) Gross Domestic Product, resident population of the region and the number of Internet broadband subscribers all have important effects on the total information flow, among which the number of Internet broadband subscribers has the greatest effect on the total information flow. In addition, urban functions and their positioning, urban events, history and culture, and other factors that are difficult to quantify also have a certain impact on the information-flow network among cities.

[Distribution and suitable habitats of ticks in the Yangtze River Delta urban agglomeration]

OBJECTIVE

To investigate the current distribution of ticks and predict the suitable habitats of ticks in the Yangtze River Delta urban agglomeration in 2017, so as to provide insights into tick control and management of tick-borne diseases in these areas.

METHODS

All publications pertaining to tick and pathogen distribution in the Yangtze River Delta urban agglomeration were retrieved, and the geographical location of tick distribution was extracted. The effects of 19 climatic factors on the distribution of ticks were examined using the jackknife method, including the mean temperature of the wettest quarter, precipitation of the coldest quarter, mean temperature of the driest quarter, maximum temperature of the warmest month, precipitation of the driest month, minimal temperature of the coldest month, annual precipitation, mean daily temperature range, precipitation seasonality, annual temperature range, temperature seasonality, annual mean temperature, mean temperature of the warmest quarter, precipitation of the wettest quarter, isothermality, mean temperature of the coldest quarter, precipitation of the wettest month, precipitation of the driest quarter and precipitation of the warmest quarter. The distribution of ticks was analyzed in 2020 using the maximum entropy (MaxEnt) model, and the potential suitable habitats of ticks were predicted in 2070 using the MaxEnt model based on climatic data.

RESULTS

A total of 380 Chinese and English literatures were retrieved, and 148 tick distribution sites were extracted, with 135 sites included in the subsequent analysis. There were 7 genera (Haemaphysalis, Rhipicephalus, Ixodes, Dermacentor, Boophilus, Hyalomma and Amblyomma) and 27 species of ticks detected in the Yangtze River Delta urban agglomeration. The climatic factors affecting the distribution of ticks in the Yangtze River Delta urban agglomeration mainly included the mean temperature of the wettest quarter and the precipitation of the coldest quarter, with 26.1% and 23.6% contributions to tick distributions. The high-, medium- and low-suitable habitats of ticks were 20 337.08, 40 017.38 km² and 74 931.43 km² in the Yangtze River Delta urban agglomeration in 2020, respectively. The climate changes led to south expansion of the suitable habitats of ticks in the Yangtze River Delta urban agglomeration in 2070, and the total areas of suitable habitats of ticks was predicted to increase by 18 100 km². In addition, the high-, medium- and low-suitable habitats of ticks were predicted to increase to 24 317.84, 45 283.02 km² and 83 766.38 km² in the Yangtze River Delta urban agglomeration in 2070, respectively.

CONCLUSIONS

Multiple tick species are widespread in the Yangtze River Delta urban agglomeration, and the future climate changes may lead to expansion of tick distribution in these areas.

Analysis on the Spatial-Temporal Evolution Characteristics and Spatial Network Structure of Tourism Eco-Efficiency in the Yangtze River Delta Urban Agglomeration

Based on the panel data of 41 cities in the Yangtze River Delta from 2008 to 2017, this paper constructs an evaluation indicators system for urban tourism eco-efficiency. By measuring the tourism eco-efficiency in the Yangtze River Delta urban agglomeration, we analyze its spatial-temporal evolution characteristics. Furthermore, the modified gravity model and social network analysis are introduced to explore the spatial network structure of tourism eco-efficiency and its evolution trend.The results show that:(1) The overall eco-efficiency of tourism in the Yangtze River Delta region presents a fluctuating downward trend, among which Jiangsu and Zhejiang have high eco-efficiency, Shanghai and Anhui are relatively low. The gap within the region first increased and then decreased. (2) During this decade, the spatial network structure of tourism eco-efficiency in the Yangtze River Delta has become increasingly loose. The weakening of the network connection strength has led to a decrease in the regional tourism eco-efficiency to a great extent. (3) The network centrality of cities such as Zhoushan, Huzhou, and Huangshan has always maintained a high level, and these cities have firmly occupied the core position of network. (4) The spatial association network of tourism eco-efficiency can be divided into four blocks: “two-way spillover”, “net spillover”, “net benefit” and “agent”. The synergy and spillover effect between various blocks are significant, and there is a spatial polarization trend centered on a few cities. Based on this, this paper puts forward optimization suggestions for the spatial network structure of the Yangtze River Delta urban agglomeration, in anticipation of promoting the improvement of regional tourism eco-efficiency.

Polycyclic aromatic hydrocarbons in the soils of the Yangtze River Delta Urban Agglomeration, China: Influence of land cover types and urbanization

With the development of urbanization, urban areas have become the main sources and sinks of polycyclic aromatic hydrocarbons (PAHs). The effects of human activities on the behaviors of PAHs in urban agglomerations have attracted significant attention. We collected soil samples (n = 330) to investigate the distribution, composition, and sources of 16 PAHs in the Yangtze River Delta Urban Agglomeration using the land resolution of 24 km × 24 km. The concentrations of Σ₁₆PAHs ranged from 21 to 2034 ng/g, with a median value of 124 ± 338 ng/g. The concentrations of PAHs were highest in impervious surfaces (350 ± 352 ng/g), followed by grassland (259 ± 322 ng/g), cropland (254 ± 341 ng/g), forest (190 ± 303 ng/g), and water (68 ± 34 ng/g). PAHs were dominated by medium-molecular-weight components (4 rings PAHs), followed by PAHs with high-molecular-weight (5-6 rings PAHs) and low-molecular-weight (2-3 rings PAHs) components. Fluoranthene, benzo[a]anthracene and chrysene are three major pollutants in YRDUA. A positive matrix factorization model indicated that fossil fuel combustion, coal combustion and volatilization, vehicle emission, and biomass burning were the main sources of PAHs, contributing 36%, 29%, 22%, and 12% of PAH sources, respectively. Urbanization parameters were positively correlated with PAH concentrations. A land use regression (LUR) model integrated with urbanization parameters showed evidence of the strong relationship between measured PAHs and predicted PAHs. These findings together highlighted that land cover types and human activities intensively influenced the PAHs pollution in the highly urbanized zones.

An Assessment of Chinese Pathways to Implement the UN Sustainable Development Goal-11 (SDG-11)-A Case Study of the Yangtze River Delta Urban Agglomeration

Urban sustainability is a crucial part of the United Nations (UN) Sustainable Development Goals (SDGs) and one of the core objectives of China’s national strategy to promote new urbanization and achieve integration in the Yangtze River Delta (YRD). This paper mainly focused on the 11th SDG, which is a universal call to make cities and human settlements inclusive, safe, resilient and sustainable. The full permutation polygon synthetic indicator (FPPSI) method was applied to synthetically evaluate the sustainable level of 26 cities in the YRD urban agglomeration from 2007 to 2016. The results showed that: (1) the synthesis indicators were increasing year by year, which implied that the sustainable development of the YRD has shown obvious progress in recent years. However, each city faced its own challenges to achieving the sustainable development goals. The sustainability level for the majority of cities was restricted by obstacles such as the per capita green area, air quality and commercial housing sales area; (2) Among the 26 cities, small and medium-sized cities were subject to the traditional strong sustainability indicators while large and mega cities were more affected by weak sustainability indicators; (3) Spatial differences were found for the overall sustainable development level of the YRD. The diffusion and assembly effect among cities had not yet been formed; however, the strong spillover effect of developed cities might influence the ability of other cities to achieve sustainable development goals in many aspects of the environment, economy and society. The results suggest the need for a stronger focus on improving regional developing patterns and strengthening coordination in the process of achieving the sustainable development goal of urban agglomeration in the YRD. Furthermore, according to the conditions of different cities, integrated policies are required to address all aspects of sustainability and to avoid unintended consequences.