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Shenzhen, a bustling metropolis in China, is currently grappling with the delicate balance between urban expansion and environmental preservation. This study finds that the disintegration of habitats due to urban development in Shenzhen city significantly impacts the ecosystem of animals and plants, detrimentally altering their living conditions. The study results reveal that the expansion of construction land in China has surged by an impressive 84.39% between 2000 and 2020, which has come at the cost of diminishing wetlands, farmland, and woodlands by 57.24%, 16.58%, and 1.86%, respectively. Between 1980–2020, the urban expanse of Shenzhen expanded dramatically, growing from 16.0 square kilometres to 850.2 square kilometres. This transformation was primarily driven by the rapid conversion of forested areas, which saw a staggering decrease of approximately 300% to 780 km2 by 2020. Additionally, half of Shenzhen's expansion can be attributed to the transformation of agricultural land, with an additional 40% stemming from the clearing of forests and approximately 9% resulting from the decrease in water resources. Furthermore, non-urban green spaces, particularly built-up areas, have significantly expanded, now encompassing approximately 60% of the city in 2018. Therefore, based on the existing literature and authoritative legal texts, this study aims to examine the legal frameworks of the Shenzhen government and, along with China's national legislation, to make room for wildlife and biodiversity conservation in a metropolis like Shenzhen. [ABSTRACT FROM AUTHOR]

Restoring the natural form and ecological function of artificial coastal zones in coastal cities can effectively improve the ecological quality of these zones. Improving the natural shoreline retention rate through this effort is also an important step in Chinese coastal cities' implementation of Xi Jinping's idea of ecological civilization. With limited resources and funds for ecological restoration, and the dual requirements of urban development and ecological protection, this study primarily focuses on how to scientifically identify the areas for ecological restoration of urban artificial coastal zones, rationally arrange the restoration schedule, and formulate the restoration strategy . This study examines 34 sections of artificial coastal zones in Shenzhen City, integrates multiple data sources to conduct spatial superposition analysis, constructs an index system for evaluating the ecological potential of artificial coastal zones, and formulates a model framework for the selection of restoration strategies, which can inform the restoration of artificial coastal zones and the management of shorelines in other coastal cities in China. The study's findings are as follows: (1) The ecological potential of Shenzhen's artificial coastal zone is spatially heterogeneous, and four different restoration response strategies can be adopted in the order of potential from high to low: "control pressure, natural restoration"; "relief pressure, ecological restoration"; "control pressure, environmental enhancement"; and "relief pressure, environmental enhancement." These correspond to four types of control zoning: ecological restoration zone, ecological recovery zone, ecological control zone, and landscape coordination zone. (2) The six sections of Xiban Park have the greatest ecological potential of Shenzhen's artificial coastline, and the restoration strategy is intended to control the external pressure and guide its natural recovery. The corresponding coastlines of these six sections constitute the first batch of new natural shorelines to be managed, to reach the target of increasing the natural shoreline retention rate of Shenzhen to 40%. (3) Nan'ao Wangyu Jiao and the other five sections of Shenzhen's artificial coastline have the second-largest ecological potential, and the restoration strategy is to relieve external pressure and take appropriate restoration measures to enhance its ecological function. The corresponding coastlines of these five sections can be managed and maintained as reserve natural coastlines. (4) The remaining 23 sections of artificial shoreline have little ecological potential and can be used as urban landscape or general public shorelines in combination with their location, without restoration intervention actions. (5) Coastal zones with high ecological potential are usually located in inlets with weak hydrodynamics, and the seaward side of such coastal zones is prone to siltation. This is conducive to the formation of new habitats and can be used as a simple indicator of whether artificial coastal zones can be restored to their natural state and ecological functions relatively quickly.

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Cities are facing increased heat-related health risks (HHRs) due to the combined effects of global warming and rapid urbanization. However, few studies have focused on HHR assessment based on fine-scale information. Moreover, most studies only analyze spatial HHR patterns and do not explore the potential driving factors. In this study, we estimated the potential HHRs based on the "hazard–exposure–vulnerability" framework by using multisource data, including the modified thermal–humidity index (MTHI), population density, and land cover. Then, the variations in the HHRs among different local climate zones (LCZs) at the fine spatial scale were analyzed in detail. Finally, we compared the different contributions of the LCZs and types of land cover to the HHRs and their three components by using multiple linear regression models. The results indicate that the spatial pattern of the HHRs was different from those of the individual components, and high-hazard regions do not mean high HHRs. There were huge variations in the HHRs among the different LCZs. The built-up LCZs typically had much higher HHRs than the natural ones, with compact LCZs facing the most severe risk. LCZ 6 (open low-rise buildings) had a relatively low HHR and should be paid more attention in future urban planning. Compared to the LCZs, the land covers better explained the variations in the HHR. In contrast, the LCZs better predicted the land surface temperatures. However, both the LCZs and land covers made only slight contributions to the heat exposure and vulnerability. Furthermore, the manmade buildings and impervious surface areas contributed much more to the HHR than the natural land covers. Therefore, the arrangement of the warming LCZs and land cover types is worthy of further investigation from the perspective of HHR mitigation. [ABSTRACT FROM AUTHOR]

With continued sea level rise and over-exploitation, saline water extends farther inland, causing changes in soil salinity and water quality and leading to permanent land salinization and ecosystem damage. Saltwater intrusion (SWI), causing numerous ecosystem problems and disasters, brings risk to urban ecosystems in coastal cities. Ecological risk, in the Greater Bay Area in China, should be assessed based on the effect of SWI status on ecosystem health. In this study, we built a new ecological risk-assessment model based on the geographic information system (GIS) technique and spatial data. At the conceptual level, four main stressors were identified based on literature reading and fieldwork. Four stress factors (SFs) were thoroughly investigated, namely, SF1: the intensity gradient immersed in saltwater; SF2: the mountain phreatic water supply; SF3: the salinity tolerance of urban greenbelt vegetation; and SF4: the supply capacity of irrigation water to suppress saline water. After a comprehensive evaluation using GIS and the analytic hierarchy process (AHP), we mapped and assessed the ecological risk level of the urban greenbelt for the SWI. Our results showed that the area of urban green space affected by the SWI was approximately 49.31 km2, almost 12.05%. Ecological risk was sorted into five ranks: (1) very low risk 47.53%, (2) low risk 26.29%, (3) medium risk 22.92%, (4) high risk 2.45%, and (5) very high risk (0.8%). The ecological infrastructure of sponges should include freshwater conservation in coastal cities, and more attention should be paid to fresh groundwater discharge from coastal ecosystems in Shenzhen. [ABSTRACT FROM AUTHOR]

Objectives: With the development of Shenzhen city, China, land renovation is more frequent. At the same time, affected by the subtropical monsoon climate, the area under the jurisdiction has abundant rainfall and dense vegetation coverage, making it difficult to identify the hidden dangers of geological hazards widely distributed on artificial slopes and natural slopes. Therefore, it is necessary to develop a set of hazard evaluation system of geological disaster that can solve the unique terrain and climate conditions in Shenzhen, so as to achieve the purpose of preventing disasters in advance and reducing casualties. Methods:(1) On the basis of highprecision digital elevation model of Shenzhen city obtained by airborne light detection and ranging(LiDAR), about 3 500 slope disaster prone points in Shenzhen are obtained through data collection, remote sensing interpretation and field verification. The sample library expanded 330% after proofreading.(2) Taking 3 major factors (8 factors) of terrain, geological structure and human engineering activities into comprehensive consideration, and based on the rainfall-induced disaster mechanism, a rainfall collection factor is proposed, and the weight of evidence method is used to complete the geological disaster hazard evaluation model under rainfall-induced conditions. (3) The threshold determination method of“key point control”under the actual background of single disaster is proposed, and the classification of the risk assessment model is completed. Results: The area under curve value of receiver operating characteristic curve model reaches 0.903, indicating that the model has a good effect on disaster forecasting. LiDAR technology can improve the identification accuracy of geological hazards in cities under dense vegetation coverage. Conclusions: Based on airborne LiDAR data, through a series of means such as expansion of disaster database, analysis of disaster distribution law, establishment of disaster evaluation factors, and classification of risk levels, it can form a refined evaluation system for the hazard evaluation of the slope in densely vegetated areas under the influence of the subtropical monsoon climate. [ABSTRACT FROM AUTHOR]

Objective To analyze the prevalence of peripheral arterial disease (PAD) among residents in Shenzhen and explore its relationship with different obesity statuses, to provide data support for understanding the prevalence of PAD in China and a basis for formulating prevention and control policies to prevent PAD. Methods From April 2021 to December 2021, a multi-stage stratified random sampling method was used to select permanent residents aged 18 years or older from 54 community neighborhood committees in Shenzhen as the study population. Data were collected using questionnaires, physical examinations, and laboratory tests. A generalized additive model was fitted and plotted using the R package, and logistic regression models were used to analyze the association between different obesity status groups and PAD. Results Among the 6 230 study subjects, the prevalence of PAD in the study population was 6.21%, and the prevalence of PAD increased with age, with the lowest rate of 4.67% in the 18-<25 age group and the highest rate of 33.33% in the ≥85 age group. In addition, the prevalence of PAD increased with increasing body mass index (BMI) or waist circumference. Analysis of multifactorial logistic regression models showed that both overall obesity (OO) classified by BMI and central obesity (CO) classified by waist circumference may increase the risk of PAD (OO statistic value OR=2.63, 95%CI: 1.97-3.50; CO statistic value OR=2.32, 95%CI:1.79-2.99). When combining BMI and waist circumference classification, compared to those who were neither OO nor CO, individuals who were both OO and CO had a significantly higher risk of PAD (OR=2.61, 95%CI: 1.99-3.44). Conclusions The prevalence of PAD among adults in Shenzhen is not optimistic, and the elderly need additional attention. Both OO based on BMI and CO based on waist circumference are independent risk factors for PAD. The joint use of BMI and waist circumference grouping helps to better classify and manage people at risk of PAD. [ABSTRACT FROM AUTHOR]

Urbanization in China has entered a new phase that emphasizes both scale expansion and quality improvement. This has led to demands on urban functional structures and rational urban planning. Street space serves as a vital spatial carrier for meeting urban residents' needs, such as travel, shopping, and leisure. It is comprised of urban roads and their ancillary facilities, buildings along the route, and many other elements. However, existing studies typically focus on the traffic function of urban roads, overlooking other functional aspects of street space as complex public activity areas, thereby hindering the optimization of street space quality. Therefore, there is a need to propose a classification method for the urban street space functions. Given the proliferation of taxi trajectory data and street view imagery, street space can be described in detail from the citizens' perspectives. Therefore, this study proposes a street space classification method that integrates taxi trajectory and street view imagery to delineate urban functions. The dynamic travel characteristics of urban residents in the street space are constructed using the taxi trajectory, including the number of trajectories passing by the street, the number of origin points on the street, and the number of destination points on the street. The physical environment characteristics of the street are constructed using the street view image, which contains single element street features, combined element street features, and overall element street features. Subsequently, based on residents' dynamic travel characteristics and the physical environmental characteristics of street space, the K-Means method is utilized to allocate street spaces with similar urban functions into the same clusters. Taking Bao'an District of Shenzhen as a case study, it was found that clustering with K=3 yielded the most interpretable results. Subsequently, based on street characteristics and auxiliary POI information (including POI density and POI enrichment index), street spaces were successfully classified into three urban functional types: commercial, traffic, and residential. Further analysis was conducted by integrating street view images, the Gaode map, and the 24-hours distribution of the trajectory, which validated the reliability of the classification results, achieving an experimental accuracy of 81%. Additionally, this study constructed two sets of ablation experiments for a comparative analysis of the effectiveness of the characteristics extracted in this study. The results of street space function classification based on taxi trajectory data and street view image data showed classification accuracies of 67% and 34%, respectively, which are lower than the classification effect of combining the two data sources. The results of street space classification based on feature selection from taxi trajectory data indicated that the classification accuracy considering only the weekday taxi trajectory features was 69%, and considering only the taxi trajectory features during T08:00-22:00 on both weekdays and weekends was 73%, which is lower than the classification effect of using three types of trajectory features throughout the entire day. By integrating the characteristics extracted from multiple data sources, the methods took into account both pedestrian and vehicle traffic functions, as well as the diversity of the streetscape environment and residents' activities. The identification results can provide references for the design and quality optimization of street space, as well as detailed investigations into urban functional areas such as residential, commercial, and traffic street space.

High-intensity land use and fragmented habitats are becoming more prevalent with urbanization, thereby accelerating the demand for maintaining and improving the ecological connectivity of habitat patches in high-density built-up areas. Previous studies have shown that small dispersed patches are crucial for enhancing connectivity across an entire landscape. However, as an important component of urban green space, residential green space in high-density built-up areas is often overlooked in ecological connectivity analysis. Taking Futian district, Shenzhen, as a case study, we explored the ecological connectivity in high-density built-up areas considering not only habitat patches but also green areas in residential quarters. We identified ecological patches and green areas in the residential areas of the study area. This was followed by a functional connectivity analysis under different scenarios. Several protection suggestions for improving ecological connectivity have been proposed based on functional connectivity analyses under different scenarios. The results show: 1) The area of residential green space in Futian district is 3.86 km2, covering 26.9% of the total green space in the study area, with the western part being sparser than other regions. The total area of the ecological patches was 14.34 km2, and the importance of the patches was not consistent with their size. The ecological connectivity of Lianhuashan Park in the central region, Lichi Park in the eastern region, and Huanggang Park in the southern region is greatly affected by the contiguous or continuously distributed strips of residential green space around them. 2) Residential green spaces affect eco-connectivity primarily by lowering corridor resistance, creating connectors for regions that require protection, and supporting biological flow. In particular, it had the largest effect on middle-resistance corridors (the unit cost distance was reduced by 29.2%) and alleviated the situation of pinch points formed in narrow low-resistance channels in high-density built-up areas. 3) The ecological pinch points that recurred in the ecological network under different scenarios of connecting residential green spaces and different resistance thresholds were identified as the most valuable primary pinch points for protection. It is recommended to strengthen the intersection of Xinzhou Road and Fumin Road and prioritize the protection of residential green spaces located near the ecological patches and on the topological connection between the ecological patches, with a scale exceeding the average size of 5,920.22 m2. Through the analysis of pinch points in various scenarios, it was found that 21 pinch points, including those close to Lianhuashan Park, could be used as substitute green spaces for urban renewal projects when nearby residential green spaces are destroyed or occupied. This supports the preservation of functional connectivity in urban renewal projects. It is increasingly difficult to construct significant habitat patches in high-density built-up areas to compensate for habitat fractures. The results identified the significant location and proportion of residential green spaces as critical bio-flow carriers in Futian District. These findings could encourage more comprehensive urban conservation plans that incorporate both sizable habitat patches and residential green spaces. These findings can be used to create more effective sustainable development plans that encourage biodiversity in urban renewal planning.

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Copyright of Tropical Geography is the property of Tropical Geography Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Understanding the complex interactions within urban social-ecological systems and revealing the characteristics of multi-layered network structures are essential for enhancing human well-being and sustainable urban management. This study proposes seven types of spatial patterns by dismantling, defining, and formalizing the urban social-ecological system processes from three primary dimensions. We use the flow-space approach to develop a method to construct urban social-ecological network model, with the primary steps including node segmentation, sub-network construction, inter-layer network construction, multi-layer network generation, and network model expression. From an ecosystem-services perspective, this study identifies coupling nodes based on the logic of matching the supply and demand of ecosystem services and then constructs a hierarchically connected social-ecological network model. Shenzhen is selected as the empirical object in this study. A social-ecological network model is constructed, containing a social sub-network, an ecological sub-network, and an inter-layer network, according to which the components of Shenzhen’s social-ecological system and its spatial distribution are analyzed. Then this study explores the robustness and small-world characteristics of social-ecological networks, and reveals that the network structure in Shenzhen has a higher average clustering coefficient and a smaller average path length. The network model constructed in this study can portray the spatial processes of social-ecological systems and retain the primary topological characteristics and geographical attributes dependent on urban issues, providing a reference for research on and management of urban socio-ecological systems. [ABSTRACT FROM AUTHOR]

With the rapid development, shared bicycles have gradually become an important part of slow urban traffic in China and have played an important role in satisfying the travel needs and facilitating the transfer of residents. Exploring the spatial and temporal characteristics of the impact of the built environment on shared bike travel is of practical importance to reshape the construction of low-carbon transportation and an urban-friendly cycling environment dominated by slow traffic and public transportation. We analyzed the spatio-temporal characteristics of shared bicycle travel through multi-source big data including Shenzhen's shared bicycle OD data, OSM road network data, Baidu Street View, and POIs and used a multi-scale geographical weighted regression model (MGWR) based on the "5D" index of the built environment to analyze the spatial difference characteristics of the impact of different built environment on shared bicycle flow. The findings of the research indicate that: (1) In terms of time, the shared bicycle flow in the morning and evening peaks of both working and rest days is more significant than that of other periods, and the peak period of the remaining days lags behind that of the working days. (2) In terms of space, the spatial distribution characteristics of the traffic flow of shared bicycles during each peak period exhibit a spatial pattern of "multiple aggregation cores and several extended belts." (3) Significant differences were observed in the impact of various built environmental factors on the flow of shared bicycle travel, among which, employment facility density, enclosure degree and population density had a positive effect in each period; their influences were globally significant; and the remaining factors demonstrated varied characteristics in each period. (4) Factors with significant influence showed different spatial scales in different periods. The spatial changes of employment facility density and enclosure in each period were generally flat; the spatial changes of proximity, density of shopping facilities, and the nearest distance to subway stations in some periods were generally flat; the spatial changes of building continuity and relative walking width were obvious in some periods. Moreover, population density and green vision rate had different spatial characteristics in different periods. This study restores the travel track of shared bicycles, analyzes the spatiotemporal characteristics of shared bicycle travel in multiple periods of working days and rest days and long-term series, and increases micro-built environment factors of subjective perception of people and experience dimension based on existing objective material space environment variables, to explore the spatiotemporal differences of the impact of different built environments on the travel flow of shared bicycles which compensate for the existing shared-bike travel time and space characteristics, build a shortage of environmental impact research, and provide references for the construction of an urban-friendly cycling environment and the creation of a slow walking space.

With the rapid development of lifestyle logistics in the service industry, such as e-commerce express and same-city delivery, new challenges have arisen in the planning and implementation of urban logistics freight and related industries. However, studies of existing urban logistics tend to focus on large-scale administrative areas, such as inter-provincial and city clusters, ignoring the importance of intra-city logistics networks. Traditional research methods are mostly based on static data to simulate inter-city logistics links, which makes it difficult to accurately and comprehensively reflect the intra-city logistics factor flows and their linkages. In response to these shortcomings, we adopted a method to track logistics in real time, by using truck GPS "flow data" across the city of Shenzhen. In addition, a community discovery model based on social networks was developed to identify important intra-city logistics nodes. The following conclusions are drawn. 1) There are 12 logistics hub nodes in Shenzhen, including the Songgang Industrial Zone, Yantian Port, and Pinghu Logistics Park, based on the infrastructure of large industrial clusters, advanced technology industrial zones, and integrated logistics parks. 2) Intra-city logistics activities are mainly concentrated on weekdays; in contrast, on weekends, logistics activities are severely inhibited by factors such as frequent activities of residents during holidays and delayed construction of planned roads. 3) The overall internal logistics linkage is weak, with logistics activities concentrated in the Guangzhou-Shenzhen axis, showing a spatial pattern of "dense in the west and sparse in the east", but the existing logistics infrastructure is mostly located in the central part of the city, which results in a misaligned layout of logistics activities heading west and logistics facilities being distributed in the middle. 4) The logistics linkage feature "heterogeneous attraction" is obvious: the logistics activities of different types of nodes tend to flow towards specific areas, gradually forming a logistics corridor with "airport-industrial area-coastal port-logistics park" as the axis. Intra-city logistics relies on the linkage of the corridor and forms a logistics corridor network model, with the corridor as the axis spreading to the periphery. 5) The intra-city logistics spatial organization can be divided into six subgroups, whose edge subgroups basically transfer logistics activities around the core subgroups, constituting a "core-edge" organization pattern. Taking these key results into consideration, we propose planning for high-quality development of intra-city logistics in Shenzhen, from three perspectives: reshaping the logistics space, adjusting planning, and cultivating new growth levels. The results of this study not only help to develop and improve the theoretical and methodological system of urban logistics network and deepen the understanding of intra-city logistics network construction, but also serve as a 'Shenzhen sample' for urban logistics development, with the goal of integrating Shenzhen into the world-class logistics hub of Guangdong-Hong Kong-Macao Greater Bay Area.

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The travel efficiency of public transportation is a key indicator for judging whether the quality of public transportation has developed compared with other modes of transportation, especially private vehicles. The quality of public transportation is also an important reference factor for residents' choices. With the rapid urban expansion and improvement in motorized travel levels, reducing the time difference between private vehicles and public transportation is the key to improving the attractiveness of public transportation. The relative spatiotemporal efficiency is based on the time difference between private vehicles and public transportation, considering the number of passengers. Recently, scholars have shown great interest in relative travel efficiency. However, relevant studies have shown poor real-time performance because of the unavailability of large datasets, which cannot dynamically reflect the characteristics of relative travel efficiency. The spread of big data and internet maps enables us to perform systematic efficiency evaluations. The internet map incorporates various travel-related information such as travel route, time, and cost under different travel modes based on real-time road conditions and provides access to the extracted embedded travel information. This study proposes a framework for evaluating the spatiotemporal efficiency of different travel modes based on real-time road conditions in Shenzhen. First, travel time data were obtained using an internet map during the morning, afternoon, and evening rush hours. The passenger flow volume was computed using smart card data. We then constructed an evaluation index model of spatiotemporal efficiency based on the relative time efficiency and weighted passenger flow volume. Finally, the results highlighted the following: 1) the relative time efficiency of public transportation was higher during the evening rush hours than in the morning. The main reason was the increase in private vehicle travel time during the evening rush hours, reflecting the complexity of urban road conditions during the evening; 2) the spatiotemporal efficiency index of central public transport stations fluctuated greatly during the three periods, which was closely related to the dynamics of traffic volume caused by the high concentration of workplaces; 3) the spatiotemporal efficiency index of public transportation stations exhibited spatial aggregation characteristics in the three periods, highlighting the different clustering characteristics in the central and outer areas; 4) the spatiotemporal efficiency index of subway stations was generally higher than that of bus stations, reflecting the importance of subway systems in urban transportation networks. Evaluating the relative travel efficiency of urban public transport contributes to analyzing the development status of public transportation, supporting decisions to achieve high-quality development of public transport, and providing travel information for the government and residents.

With continued sea level rise and over-exploitation, saline water extends farther inland, causing changes in soil salinity and water quality and leading to permanent land salinization and ecosystem damage. Saltwater intrusion (SWI), causing numerous ecosystem problems and disasters, brings risk to urban ecosystems in coastal cities. Ecological risk, in the Greater Bay Area in China, should be assessed based on the effect of SWI status on ecosystem health. In this study, we built a new ecological risk-assessment model based on the geographic information system (GIS) technique and spatial data. At the conceptual level, four main stressors were identified based on literature reading and fieldwork. Four stress factors (SFs) were thoroughly investigated, namely, SF1: the intensity gradient immersed in saltwater; SF2: the mountain phreatic water supply; SF3: the salinity tolerance of urban greenbelt vegetation; and SF4: the supply capacity of irrigation water to suppress saline water. After a comprehensive evaluation using GIS and the analytic hierarchy process (AHP), we mapped and assessed the ecological risk level of the urban greenbelt for the SWI. Our results showed that the area of urban green space affected by the SWI was approximately 49.31 km2, almost 12.05%. Ecological risk was sorted into five ranks: (1) very low risk 47.53%, (2) low risk 26.29%, (3) medium risk 22.92%, (4) high risk 2.45%, and (5) very high risk (0.8%). The ecological infrastructure of sponges should include freshwater conservation in coastal cities, and more attention should be paid to fresh groundwater discharge from coastal ecosystems in Shenzhen.

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Copyright of Tropical Geography is the property of Tropical Geography Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Recently, dockless bikeshare (DBS), a new bikeshare program that does not feature fixed dock stations, has been developed rapidly in China and has also offered a decent solution to the first- and last-mile problem. In addition, the integration of DBS and metro strongly promotes the transit-oriented development, particularly in the metropolitan areas of China. To achieve the seamless connection between DBS and metro transit, the spatial variation of the effects of urban built environment, particularly in high-density metropolitan areas, should be explored to advance the targeted policy interventions in different urban spaces. Using data from one of the largest DBS operators in China (ofo), this study measured the integrated use of DBS and the metro quantitatively, and it employed geographically and semiparametric geographically weighted regression (GWR and SGWR, respectively) to examine the effects of the built environment on the integrated use, using Shenzhen as a case study. The findings show that (1) The SGWR model performs better than GWR and OLS in explaining the relationship between built environment and access integrated use, whereas SGWR is not applicable for the egress integrated use. (2) Three positive determinants of population density, major road length and inbound metro ridership, and three negative determinants of metro density, secondary school, and intersection density have been examined with spatial effects on the access integration. (3) For egress integration, official land use, park, bus stops, and outbound metro ridership have positive and spatial effects, while residential land use, number of secondary school, metro density and distance to CBD (Central Business District) exert negative spatial effects. The results indicate that the built environment elements usually affect the integrated use with spatial variation. Furthermore, the access and egress integration use of DBS metro largely depends on the characteristics of built environment of the origin and destination metro catchment, respectively. This work provides insight into how the DBS-metro integration, which is divided into access and egress patterns, is spatially affected by urban built environment in the Chinese metropolitan context. The results will also provide a reference for the local government to carry out the targeted policies and planning to encourage the connection between DBS and metro transit more successfully. For DBS operators, the results also contribute to allocating the bikes more efficiently, which is adapted to the dynamic demand-supply at different urban spaces.

Construction activities of accelerated urbanization in Shenzhen have increased the landslide risk area, which has intensified the potential threat to human and natural environment. However, the risk of landslides in Shenzhen is poorly evaluated. In this article, a landslide risk evaluation (LRE) model is constructed using landslide susceptibility map (LSM) and landslide vulnerability. In the experiment, a stacking ensemble learning (SEL) model is constructed based on convolutional neural network (CNN), multilayer perceptron, gated recurrent unit (GRU), and support vector machine regression to generate LSM by using topography, geology, human engineering activities, time-series precipitation, and time-series normalized difference vegetation index. Road network, building distribution density and annual average precipitation data are used to evaluate landslide vulnerability based on entropy weight method. In this article, multiple statistical indicators are used to evaluate the performance of the LSM model, and Interferometric Synthetic Aperture Radar (InSAR) deformation data are utilized to verify the LRE results in Shenzhen. The results show that the SEL method has more refined results for LSM, with a best overall evaluation accuracy, especially in the receiver operating characteristic curve, where the accuracy is improved by nearly 8%. In LRE of Shenzhen, very high, high, moderate, low, and very low risk areas account for 0.283%, 0.451%, 0.859%, 36.890%, and 61.517%, respectively. In most of very high-risk area, InSAR deformation results show a clear concentrated deformation trend with a large deformation rate. Research results can provide technical and data support for landslide disaster prevention in Shenzhen.

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The study investigated the composition and content of Σ15PAH in the surface and core sediments from Dachan Bay (DCB) in Shenzhen city and discussed the effects of urban development and regional energy structure on the marine environment through the spatial distribution, vertical profile, and sources of Σ15PAH. The results indicated that the concentrations of Σ15PAH in the sediments of DCB ranged between 299 ng/g and 2336 ng/g in the surface sediments and between 65 ng/g and 994 ng/g in the core sediments. The horizontal spatial distribution of PAHs content with decreasing concentrations from the coastal to central areas implied the land-based input of PAHs. The vertical profile of high PAHs concentration in 0 cm–60 cm suggested that the PAHs pollution is attributed to the urban development of Shenzhen since 1950, especially after the 1980s. According to features of the low molecular weight (LMW)/high molecular weight (HMW), PAHs diagnostic ratios and their relationships with total organic carbon (TOC) and oil, the pyrogenic PAHs were mainly from the combustion of petroleum and byproducts in the surface and 0 cm–60 cm sediments but from the combustion of biomass in 60 cm–190 cm sediments, which corresponded with the variation of energy structure in surrounding areas. This study suggested that urban development and regional energy structure have a great impact on PAHs distribution in DCB and further controls of land-based pollutant emissions are still needed. [ABSTRACT FROM AUTHOR]

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The safe and stable operation of the urban water supply network system is vital for the development of the city and people's daily life. However, the aging and damage of some pipelines are inevitable as time passed by. Accidents, such as pipe bursting, will happen if the maintenance is not timely or not in place. Aiming at the emergency event of the water supply pipe network burst, this paper took the main water supply line of Shenzhen North Line as an example, and established a one-dimensional (1D) hydrodynamic model suitable for both pressurized water flow and free surface water flow. The rationality and effectiveness of the model were verified through the analysis of the simulation results (water level, flow, water head, etc. at each section) under normal conditions. The 1D hydrodynamic pipe network model under burst conditions was constructed based on the normal conditions. The flow stability time of the burst position obtained by the model is 24100 s in which the water supply flow is reduced to 0m3/s after the pipe burst, and flow stability time of the pipe section is positively correlated with the distance of the pipe section according to entrance. By assuming different burst sections, the correlation between the distance of the inlet section of the burst stability time pipeline after the burst at different positions was simulated. The research results can provide strong data support for emergency maintenance decisions if a pipe burst has happened and it also provides an idea for the hydrodynamic modeling of pipeline network emergencies. [ABSTRACT FROM AUTHOR]

History has witnessed a long list of flood events and resilience has been a topical concept in flood risk assessment. However, previous studies did not integrate resilience into urban flood risk assessment frameworks and describe the merits of considering resilience in them. Here, a case study was conducted in Shenzhen City with an improved resilience metric based on system performance curve and the maximum and minimum water depth thresholds. A novel urban flood assessment framework was developed and compared with a conventional framework using hazard, vulnerability, and flood risk maps. The results demonstrate that in the resilience-based framework, some areas with high maximum inundation depths and long inundation durations have lower hazard than the framework without resilience because of their high resilience. More areas with low resilience are classified as very high hazard zones and hazard levels of some areas with high resilience decrease. The resilience-based framework considers the impact of land use type without using it as an index. The calculations are simplified and there is a greater emphasis on economic loss and casualties. Flood risk levels of areas in traffic lands increase while commerce, residence, greenspace, and waterbody decrease. The results suggest that integrating resilience into the urban flood risk assessment framework has substantial merits and resilience should be considered when assessing urban flood risk. [ABSTRACT FROM AUTHOR]

The market-oriented real estate development model has occupied a leading position in the urban renewal activities in Shenzhen and the regeneration of the old city has shown serious stagnation under the intertwined interests of multiple subjects. This study took the Mutoulong Community (Shenzhen, China), Luohu District as an example to resolve and analyze the project promotion process and explore the core problems of the old city regeneration in Shenzhen. The results showed that the internal contradictions and conflicts between the owners of different factions were the core problem of stagnation in the old city regeneration. In addition, from the case study on the application of a third-party professional force in Hubei New Village (Shenzhen, China), Shenzhen and the project that funded the building in Macao Special Administrative Region (SAR), the results show that the third-party professional forces are professional, nonprofit, and prioritized public interests, which could effectively balance the cognitive differences between the owners of different factions in the planning policy, design scheme, and implementation, which helped to build trust between the owners and other subjects. In addition, the third-party professional forces with a resident composition will help to resolve the complex ownership relationships and effectively promote the development of the old city regeneration projects. [ABSTRACT FROM AUTHOR]

With the acceleration of urbanization in South China, rainstorms and floods are threatening the safety of people in urban areas. The 11 April 2019 (4·11 hereafter) rainstorm in Shenzhen City was a typical pre-rainy season rainstorm that caused great damage, yet such pre-rainy season events have not attracted sufficient attention in research. Risk perception of the public may indirectly affect their disaster preparedness, which is important for disaster management. In this study, we conducted a questionnaire survey that considered demographic factors and the level of risk perception, knowledge of risk, impact of the 4·11 rainstorm event on public risk perception, and degree of trust in the government. We used a two-factor model of risk perception to evaluate the factors that influenced public risk perception of the 4·11 rainstorm in Shenzhen. The main conclusions are: The 4·11 rainstorm improved public awareness of both risk and impact through the medium term, but the public's perceived low probability of disaster occurrence and lack of knowledge of the pre-rainy season rainstorm phenomenon led to serious losses during this event. Although the public has high trust in the Shenzhen government, the management of rainstorm disasters in the pre-rainy season needs to be further improved. [ABSTRACT FROM AUTHOR]

Foliar dust retention is a crucial source of uncertainty when monitoring the vegetation index using satellite remote sensing. As ground sampling conditions are limited by vegetation dust retention, separating the extinction effect of foliar dust retention from the normalized difference vegetation index (NDVI) poses a significant challenge. In this study, we conducted a correlation test between the relative change in NDVI (δNDVI, an indicator of extinction effect) retrieved by the Gaofen-4 satellite and the atmospheric PM10 concentration in different meteorological periods (before, during, and after rainfall) across 14 stations in Shenzhen City, China. The results showed a significant correlation between δNDVI and atmospheric PM10 concentration during the before-rainfall period and weaker correlations for the other periods (R = 0.680, p < 0.001, n = 63 when excluding the during- and after-rainfall data). The correlation was more significant for the stations with low NDVI values, and a coastal station had a distinct regression slope of δNDVI versus PM10 from the other stations, indicating that the extinction effect of foliar dust retention in high-NDVI and coastal areas may not be well predicted by the general δNDVI–PM10 relationship. This provides a new quantitative basis for estimating the extinction effect of foliar dust retention using PM10 data for future improvement of the accuracy of vegetation monitoring by remote sensing. [ABSTRACT FROM AUTHOR]

Cities and urban areas are an important part of global sustainable development, and the health and well-being of urban residents are closely related to the quality, quantity, and diversity of urban ecosystem services. Although the rapid urbanization process has changed the structure and function of urban ecosystems, which is notably different from natural ecosystems, the affected ecosystem services and their interactions—the trade-off impact of urbanization intensity on ecosystem services—remain to be discussed. Using land use/land cover and impervious surface area remote sensing datasets, and InVEST and RUSLE-related ecosystem services models to evaluate seven typical ecosystem services in Shenzhen, this study explored the evolution of multiple ecosystem service trade-offs and synergies during the transition from a natural ecosystem to an urban ecosystem, and how they are affected by urbanization intensity through correlation analysis and a discrete time-step simulation model. The results show that: (1) from 1978 to 2018, in the process of ecosystem transformation, grain production dropped from 228,795 tons to 11,733 tons, fruit production peaked in 1990 at 271,508 tons, and service capacity of both showed obvious degradation. Conversely, the cultural service capacity was remarkably enhanced. (2) With the increase in urbanization level, the trade-off and synergy of ecosystem services gradually transition from linear to nonlinear. The rapid urbanization process drives the nonlinear degradation of ecosystem services and the nonlinear enhancement of synergy. (3) Over the past four decades, ecosystem service bundles within the same kilometer grid have shown a quadratic curve-like decrease with increasing impervious surface area, slowly in the early stages and faster in the later stages. This study concludes that urbanization intensity has a significant impact on ecosystem service trade-offs, which can provide support for the formulation of ecological protection and restoration strategies in territorial space based on ecosystem services. [ABSTRACT FROM AUTHOR]

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The consumer service industry directly provides residents with material and spiritual living consumption services and products to meet residents' consumption needs. The reasonable spatial layout of the consumer service industry is of great significance for improving residents' quality of living, optimizing the urban spatial structure, and alleviating urban problems. Based on consumer service point of interest (POI) data, mobile phone signaling data, and population data from Shenzhen, using the nearest neighbor index, kernel density, and entropy index methods, this study analyzes the spatial pattern of the overall and different types of consumer service industry as well as the spatial characteristics of the degree of mixing in the consumer service industry in Shenzhen. Using the Geodetector method, this study also detects the impacts of seven factors, including population, traffic, economy, and space dimensions, on the overall and different types of consumption service industry as well as analyzing the impacts of population age structure on the spatial pattern of this industry and its types. This study is expected to provide a theoretical and decision-making basis for urban planning and development in Shenzhen and other cities. The results show that: 1) The spatial distribution of the consumer service industry in Shenzhen is unbalanced and is concentrated in the central and western regions. The consumer service industry presents the spatial characteristics of two core areas and three belt areas. The two core areas are the Dongmen business area in Luohu District and the Huaqiangbei business area in Futian District. The three belt areas consist of the Luohu-Futian belt, Nanshan-Baoan belt, and Longhua belt. The spatial distribution of the consumer service industry has developed along strips and is mainly concentrated in the areas around the main roads and rail lines. 2) The spatial agglomeration characteristics of the overall and different types of consumer service industry are remarkable and differentiated in Shenzhen. The spatial distribution characteristics of most types of consumer services are similar to those of the overall consumer service industry. The development of industry in some areas has resulted in differences in the spatial distribution of certain categories. 3) The balance of the consumer service industry is better in the Luohu, Futian, Nanshan District and worse in the other Districts. The high balanced areas are the edge areas outside the two core areas, rather than the two core areas with the highest POI density. 4) Population density factors are the most important factors affecting the spatial pattern of the consumer service industry, followed by traffic factors. The influence of economic and spatial factors is relatively low. 5) The population of people aged 19-35 has the greatest impact on the density of the consumer service industry. Age groups have different impacts on the spatial distribution of different types of consumer service industries because of specific needs. These results are consistent with the spatial planning of urban functional zoning and industrial development layout in the Shenzhen Urban Master Plan (2010-2020). Combining these results and current urban development activities, this study provides suggestions for optimizing the spatial layout of the consumer service industry in Shenzhen.

Abstract Background With the increasing fragmentation of landscape induced by rapid urbanization, the construction of ecological networks is of great significance to alleviate the degradation of urban habitats and protect natural environments. However, there is considerable uncertainty when constructing ecological networks, especially the different approaches to selecting ecological sources. We used the southern Chinese city of Shenzhen as a study area to construct and optimize ecological networks using a coupling approach. Ecological source areas were extracted using morphological spatial pattern analysis (MSPA) and the landscape index method. Ecological networks were constructed using the minimal cumulative resistance (MCR) model and the gravity model. Stepping stones and ecological fault points were added in corridors to optimize the ecological network. Results Ten core areas with maximum importance patch values were extracted by the landscape index method as ecological source areas according to MSPA, after which corridors between ecological sources were constructed based on the MCR model. The constructed ecological networks were optimized using 35 stepping stones and 17 ecological fault points. The optimized ecological networks included 11 important corridors, 34 general corridors, and seven potential corridors. The results of corridor landscape-type analysis showed that a suitable ecological corridor is 60 to 200 m wide. Conclusions Overall, our results imply that ecological source areas can be identified virtually, and that ecological networks can be significantly optimized by combining MSPA and MCR models. These results provide a methodological reference for constructing ecological networks, and they will be useful for urban planning and biodiversity protection in Shenzhen and other similar regions around the world.

Sustainable Development Goals propose to build inclusive, safe, resilient, and sustainable cities and human settlements, which requires us to scientifically evaluate the carrying capacity of current urban public service facilities, but there is still a lack of in-depth exploration of urban public medical service facilities. Therefore, this paper, within the mobile phone signaling data, improved the potential model and carrying capacity evaluation model of public medical facilities, explored the spatial pattern distribution of public medical resources in Shenzhen, and analyzed the current situation of carrying capacity of public medical resources. The study showed that: (1) the overall spatial distribution of public medical resources in Shenzhen is uneven, showing a pattern of multicenter aggregation and multilevel development; (2) the service potential of public medical facilities has obvious spatial variations, with Futian District, Dapeng New District, and Nanshan District showing more obvious high-gravitational-value aggregation centers; (3) medical facilities in Shenzhen are never empty, but the problems of medical underloading and overloading are severe, and spatial allocation and utilization efficiency need to be further optimized. The research results can provide a scientific basis for the research on the allocation and sustainable construction of medical resources in megacities. [ABSTRACT FROM AUTHOR]

Background: With the increasing fragmentation of landscape induced by rapid urbanization, the construction of ecological networks is of great significance to alleviate the degradation of urban habitats and protect natural environments. However, there is considerable uncertainty when constructing ecological networks, especially the different approaches to selecting ecological sources. We used the southern Chinese city of Shenzhen as a study area to construct and optimize ecological networks using a coupling approach. Ecological source areas were extracted using morphological spatial pattern analysis (MSPA) and the landscape index method. Ecological networks were constructed using the minimal cumulative resistance (MCR) model and the gravity model. Stepping stones and ecological fault points were added in corridors to optimize the ecological network. Results: Ten core areas with maximum importance patch values were extracted by the landscape index method as ecological source areas according to MSPA, after which corridors between ecological sources were constructed based on the MCR model. The constructed ecological networks were optimized using 35 stepping stones and 17 ecological fault points. The optimized ecological networks included 11 important corridors, 34 general corridors, and seven potential corridors. The results of corridor landscape-type analysis showed that a suitable ecological corridor is 60 to 200 m wide. Conclusions: Overall, our results imply that ecological source areas can be identified virtually, and that ecological networks can be significantly optimized by combining MSPA and MCR models. These results provide a methodological reference for constructing ecological networks, and they will be useful for urban planning and biodiversity protection in Shenzhen and other similar regions around the world. [ABSTRACT FROM AUTHOR]

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Context: The rapid urban expansion in southern coastal regions of China can endanger the quality and connectivity of bird habits and thus challenge our capacity for protecting bird species in urban areas. Identifying the ecological corridors that allow migratory birds to and from urban green landscapes is therefore essential for conserving biodiversity in urban areas. Objectives: This study aimed to explore how urban expansion in vertical direction affects the flying paths of migratory birds and seek measurements to enhance bird migration to and from urban areas. Methods: The ecological security pattern (ESP) for migratory birds in a coastal region near the Shenzhen city of China was determined based on three-dimensional landscape data and results were evaluated against historical eBird record abundance data. Results: The positive agreement with historical bird abundance demonstrated that the consideration of three-dimensional landscape in parameterizing the resistance for ESPs can help identify the flight corridors for migratory birds in urban areas and the consequent sixteen key flight corridors with a total length of 454.78 km were identified in and around the Shenzhen city. Conclusions: The three-dimensional landscape data are essential for identifying flight corridors for migratory birds to and from urban landscapes. The extracted flight corridors in and around the Shenzhen city connected natural reserves with urban parks, thereby enlarging bird habitats and its conservation inside the Shenzhen city. [ABSTRACT FROM AUTHOR]

In the formation process of megacities, urban population is constantly gathering from other cities to large and medium-sized cities, and from the periphery of the city to the center of the city, inducing traffi c congestion, overload of main center, reduction of space effi ciency, and other major urban diseases. Multi-center urban spatial structure is an effective way to solve the above negative externalities. It is helpful to evaluate the effi ciency of the existing industrial distribution structure in the cities and make a reasonable estimate of the future enterprise growth by clarifying the interactive relationship between the development process of a city and the change of the employment center. Based on survey data of Shenzhen "Four Up-scale Enterprises" in 2017, threshold method is used to identify the existing employment centers of Shenzhen, and describe the characteristics of each employment center. Combining calculation of industry location entropy, below conclusions are obtained: ① the double main centers (Futian-Luohu center and Nanshan center) in Shenzhen are obvious, and the weak multi-center has initially formed; ② the development of the industry is relatively balanced in Futian-Luohu center, and Nanshan center has absolute advantage in information technology industry; ③ the employment centers outside the original special economic zone are mainly manufacturing industries, showing a highly specialized trend of industries, and cultivation of service industries is insuffi cient. [ABSTRACT FROM AUTHOR]

In order to grasp the climate change law of extreme precipitation in Shenzhen, based on the daily precipitation data of Shenzhen from 1961 to 2019, 11 extreme precipitation indexes and coefficients of variation were calculated, and abnormal values of annual precipitation were detected. Linear trend method and Mann-Kendall were used. Catastrophe analysis and other methods analyzed the changes of extreme precipitation and abnormal precipitation in Shenzhen. The results show that in the past 59 years, Shenzhen's extreme precipitation index has significant fluctuation characteristics; the daily precipitation thresholds for determining heavy and extremely heavy precipitation are 59.7 mm and 130.4 mm, respectively, which roughly correspond to the level of heavy rain and heavy rain; extreme precipitation changes are mainly manifested as follows: The number of moderately rainy days (R 10) increased significantly; the maximum 1-day precipitation (R x1day), the maximum 5-day precipitation (R x5day ), and the number of moderate rain days (R 10), three extreme precipitation indices, all changed abruptly around 1980 1963 was a typical year with abnormally low precipitation, and 2001 and 2008 were typical years with abnormally high precipitation. In the past 30 years, the frequency of abnormal annual precipitation has increased significantly, twice as much as the previous 29 years. The above results all indicate that Shenzhen faces a high risk of urban waterlogging disasters in the future. [ABSTRACT FROM AUTHOR]

Sustainable Development Goals propose to build inclusive, safe, resilient, and sustainable cities and human settlements, which requires us to scientifically evaluate the carrying capacity of current urban public service facilities, but there is still a lack of in-depth exploration of urban public medical service facilities. Therefore, this paper, within the mobile phone signaling data, improved the potential model and carrying capacity evaluation model of public medical facilities, explored the spatial pattern distribution of public medical resources in Shenzhen, and analyzed the current situation of carrying capacity of public medical resources. The study showed that: (1) the overall spatial distribution of public medical resources in Shenzhen is uneven, showing a pattern of multicenter aggregation and multilevel development; (2) the service potential of public medical facilities has obvious spatial variations, with Futian District, Dapeng New District, and Nanshan District showing more obvious high-gravitational-value aggregation centers; (3) medical facilities in Shenzhen are never empty, but the problems of medical underloading and overloading are severe, and spatial allocation and utilization efficiency need to be further optimized. The research results can provide a scientific basis for the research on the allocation and sustainable construction of medical resources in megacities.

Rapid urbanization has created daunting challenges with respect to the demand for cultural ecosystem services (CES). Recreation is a special CES provided by the biophysical properties of parks in the city. However, assessment of the CES of parks remains challenges partly due to the lack of appropriated framework at community level, and partly because of paucity of information on park demand. This study uses spatially explicit approaches including recreation accessibility and potential indicators and multi-sources data such as crowd-sourced information form Point of Interests (POIs) to map the supply and demand for CES of parks. Then, the spatial statistics were used to identify unbalanced communities to reveal the pattern to support landscape planning at the city scale. The results show that 33.76% of Shenzhen’s community, concentrated in the central urban area, was characterized by a large supply of CES with a strong spatial aggregation. A total of 39.4% of the communities had high demand for CES, and were scattered in the central urban areas and suburbs. This mismatch in distribution shows that 29.8% of the communities had inadequate supply relative to demand. Moreover, 5% of the communities were prioritized to plan new parks while only 2.6% had the potential to share their services. The new park planning priority was determined according to the significance of low supply-high demand communities and its surroundings, which helped for local development planning. This study provides a comprehensive spatial way to make park planning and management in rapidly urbanizing areas.

The disasters of encounter of extreme rainstorm and high tide level will aggravate the flood in coastal cities.In order to explore the impact of the encounter of rainstorm and tide on flood control and drainage in coastal cities,based on the annual maximum 1 day rainfall and its corresponding tide level data of Chiwan Station in Shenzhen from 1967 to 2018,the Copula function is used to construct a joint distribution model of annual maximum 1 day rainfall and its corresponding tide level,and the co-occurrence risk,the flood control risk,the condition risk and the combination risk of rain and tide in Shenzhen are calculated and analyzed.The results show that the risk of the encounter of rain and tide in Shenzhen is small,and the co-occurrence and combination risk probability of rainfall whose return period greater than 100 years and tidal level whose return period greater than 200 years are only 0.12% and 0.09%.The probability of the occurrence of rainfall or tide exceeding the standard magnitude is 1.09%,and its return period is less than 100 years.When the rainfall exceeds the standard magnitude,the probability of encountering an over-standard tide level is greater,with a probability of 12.33%.At the same time,with the increase of rainfall,the risk will also increase.Therefore,in the planning and design of flood and tide prevention and drainage in cities,the focus should be on attention and prevention.

Copyright of Chinese Journal of Applied Ecology / Yingyong Shengtai Xuebao is the property of Chinese Journal of Applied Ecology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)