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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]

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]

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]

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]

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]

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]

The thermal-environment effect exists in the field of rapid urbanization. It has adverse effects on the urban atmosphere, regional climate, energy consumption, and public health. Shenzhen, a representative of rapidly urbanizing cities in China, was selected as a case for pattern dynamics analysis of the thermal environment. The surface temperature was acquired from the thermal infrared data of Landsat TM and ETM+ images in 1986, 1995, and 2005 by Jiménez-Muñoz and Sobrino's generalized single-channel method, which was used in assessing the distribution and spatial patterns of the thermal environment. The relative thermal environment curve (RTC) was combined with Moran's I analysis to assess the pattern dynamics of the thermal environment in different urbanization periods. Moran's I index and the RTC represent a process of aggregation-fragmentation-aggregation, which shows the aggregation pattern of a decrease during the rapid urbanization period and then an increase during the steady urbanization period. High-temperature areas gradually expanded to a uniform and scattered distribution in the rapid urbanization period; while the high thermal-environment effect was gradually transformed into a steady spatial pattern in the stable urbanization period. To characterize the increasing development in this multiple-center city, we chose profiles along an urban-development axis. The results suggest that heat islands have expanded from internal urban to external urban areas. Four profiles were obtained showing differences in shape due to spatial differences in the process of development. [ABSTRACT FROM AUTHOR]

We presented measurements of wet deposition of NH-N and NO-N from 1986 to 2006 in Shenzhen City, China. Over the past 20 years, NO-N concentration had significantly increased, but a reverse trend was found for NH-N. The main form of total inorganic nitrogen (TIN) was NH-N and the average NH-N/NO-N ratio was 1.57 in this area. The contribution of NO-N to TIN increased from 28-42% in the period of 1986-2000 to 50-63% during 2001-2006. The increased deposition flux of NO-N resulted in the increasing trend of TIN, although NH-N showed a decreasing trend over time. Average deposition flux of TIN during 1986-2006 was 13.24 kg/ha/year, with a minimum value of 6.03kg/ha/year in 1988 and a maximum value of 20.52 kg/ha/year in 1997. Wet deposition fluxes of N appeared to vary with season, 81% occurred in the warm season (from April to September). The wet deposition of TIN to the Shenzhen Reservoir reached 8,902 kg in 2006, which contributed 9.95% of the total nonpoint pollution to the reservoir and will be increased in the future. [ABSTRACT FROM AUTHOR]