69.Urbanization impact on the supply-demand budget of ecosystem services: Decoupling analysis
Ecosystem Services, August 2020
JianPeng, Xiao yu Wang,Yanxu Liu, Yan Zhao, Zihan Xu,Mingyue Zhao,Sijing Qiu,Jiansheng Wu
Abstract:Correlation of ecosystem services (ES) considering both the supply and demand sides remains unclear, and research on urbanization impact on the ES supply-demand budget is lacking. Taking the rapidly urbanizing Pearl River Delta (PRD) urban agglomeration of China as an example, eight ES supply, demand and the supply-demand budget of 374 watersheds were quantified using an expert-based matrix. The trade-offs and synergies of ES were then explored from both the supply and demand sides, with identifying the ecosystem service bundles (ESBs) of supply, demand, and the supply-demand budget separately. Through decoupling analysis, the urbanization impact on the ES supply-demand budget was explored. The results showed that ESs were well supplied in high-altitude areas in the PRD urban agglomeration, and that watersheds with insufficient ES supply were concentrated along the Pearl River where population density was high. It was also observed that there were significant synergistic relationships in the ES supply-demand budget. And the average decoupling index of the supply-demand budget for total ES and the three urbanization indicators increased from GDP to DN of nighttime light, and to Population density. It is an important way to identify the trade-offs and synergies between ES supply-demand budgets, and to explore the decoupling between the ES supply-demand budget and urbanization, in order to provide comprehensive decision-making support for ES management in rapidly urbanized areas.
International Journal of Disaster Risk Reduction, June 2020
Wu Jiansheng, Zhao Yuhao,Yuan Tian, Chen Bikai
Abstract:This paper presents an analysis of the comprehensive risks associated with the typhoons in the China coastal main functional area from 1991 to 2010, a prediction of the changes of these comprehensive risks in the future, and mitigation measures to limit the impact of these disasters on the economy and the population. The analysis is based on the two main criteria of vulnerability and danger. The former includes socioeconomic factors of the regions affected by typhoon, namely the population and GDP. The latter reflects the intensity of the typhoon itself. Our analysis reveals that: (1) The impact of typhoons on coastal provinces is highly variable in space, the province of Hainan, and coastal cities in Guangdong, Fujian and Zhejiang provinces being the most severely affected; (2) From 1991 to 2010, the risk associated with typhoons showed an upward trend in China's coastal cities, with the vulnerability increasing gradually from the inland to the coastal areas; (3) Regions comprising both medium and low risk areas, functional zoning should be adjusted according to the distribution of risk in those regions, and in high risk areas, emphasis should be given on improving the current disaster prevention and mitigation measures, especially with regards to the implementation of better early warning system and post-disaster management. This article analyzes and simulates the typhoon risk changes of the four main functional areas in the coastal of China for the first time, and proposes disaster avoidance measures, which can provide reference for relevant policy makers.
Science of The Total Environment,15 May 2020
ZhenyuWang*,Alex MarkLechner,YongjunYang,ThomasBaumgartl,JianshengWua
Abstract:Open-cut coal mining can seriously disturb and reshape natural landscapes which results in a range of impacts on local ecosystems and the services they provide. To address the negative impacts of disturbance, progressive rehabilitation is commonly advocated. However, there is little research focusing on how these impacts affect ecosystem services within mine sites and changes over time. The aim of this study was to assess the cumulative impacts of mining disturbance and rehabilitation on ecosystem services through mapping and quantifying changes at multiple spatial and temporal scales. Four ecosystem services including carbon sequestration, air quality regulation, soil conservation and water yield were assessed in 1989, 1997, 2005 and 2013. Disturbance and rehabilitation was mapped using LandTrendr algorithm with Landsat. We mapped spatial patterns and pixel values for each ecosystem service with corresponding model and the landscape changes were analyzed with landscape metrics. In addition, we assessed synergies and trade-offs using Spearman's correlation coefficient for different landscape classes and scales. The results showed that carbon sequestration, air quality regulation and water yield services were both positively and negatively affected by vegetation cover changes due to mined land disturbance and rehabilitation, while soil conservation service were mainly influenced by topographic changes. There were strong interactions between carbon sequestration, air quality regulation and water yield, which were steady among different spatial scales and landscape types. Soil conservation correlations were weak and changed substantially due to differences of spatial scales and landscape types. Although there are limitations associated with data accessibility, this study provides a new research method for mapping impacts of mining on ecosystem services, which offer spatially explicit information for decision-makers and environmental regulators to carry out feasible policies, balancing mining development with ecosystem services provision.
Science of The Total Environment,1 May 2020
YuhangLuo,JianshengWu*,XiaoyuWang,ZhenyuWang,YuhaoZhao
Abstract:The acceleration of urbanization has aggravated the fragmentation of ecological patches and increased the uncertainty risk of habitat connectivity. In the context of landscape fragmentation, government need to establish sound policies that effectively protect the stepping-stones of habitat connection and realize urban ecological integration. In this study, a circuit theory model was used to identify the potential ecological corridors in the city and corresponding stepping-stone groups, with two important stepping-stone groups selected as our areas of focus. By establishing the potential linkages between stepping-stone nodes, we constructed stepping-stone networks within the potential ecological corridors and formulated four scenarios to analyze the robustness of the stepping-stone networks under different policies. The results show that there are 46 important habitats and 22 potential ecological corridors in Shenzhen, including 22 stepping-stone networks. The most important stepping-stone network in the central Shenzhen area connects 7 important habitats and contains 110 stepping-stone nodes. The most important stepping-stone network in the northeast area of Shenzhen connects 5 important habitats and contains 130 stepping-stone nodes. Comparing the robustness and form of the stepping-stone networks under the four policy scenarios, we found that the centrality of stepping-stones is of great significance for maintaining the connectivity of important habitats. For instance, there are five stepping-stone networks in Shenzhen that have not been successfully protected by existing ecological protection policies because their highly central nodes are vulnerable to threats. This study analyzed the maintenance of habitat connectivity under different ecological protection policies in the process of urbanization and discussed the significance of highly central stepping-stone nodes in maintaining habitat connectivity. With this effort, a new perspective on habitat connectivity protection under landscape fragmentation is provided, producing a reference for the formulation of urban ecological protection policy.
Scientific reports, April 2020
Wu Jiansheng,Sha Wei,Zhang, Puhua,Wang Zhenyu
Ecological Indicators, April 2020'
XueruJin,XiaoxianLi,ZheFeng*,JianshengWu,KeningWu
Abstract:As natural resources are becoming one of the factors hindering economic development, the utilization efficiency of natural resources should be improved and ecological stress should be reduced to ensure sustainable economic development. In this study, the ecological stress index and ecological efficiency were quantified using the ecological footprint model to describe the current status of sustainability and utilization efficiency of natural resources. The economic agglomeration was determined by conducting global spatial autocorrelation analysis using Defense Meteorological Program/Operational Line-Scan System (DMSP/OLS) nighttime light data. The relationship between economic agglomeration and ecological efficiency of China was then illustrated in a four-partite graph, and the results show that (1) the per-capita ecological footprints vary between the different provinces; however, the composition of the ecological footprint is similar between the provinces, and demonstrates the demand for fossil energy land is highest, while that for fishing ground is lowest. (2) All provinces are facing ecological overload, excluding Qinghai, and Shanghai, Tianjin, and Beijing are enduring the most severe ecological overload. (3) The ecological efficiency differs greatly between the different provinces of China, and the ecological efficiency values tend to decrease from the eastern coast to the inland region. (4) The economic activities in every province of China are spatially agglomerated, and the degree of agglomeration differs significantly. (5) There is a positive correlation between economic agglomeration and ecological efficiency, indicating that promoting economic agglomeration is an effective method of improving the utilization efficiency of natural resources. The relationship between economic agglomeration and ecological efficiency observed in this paper will provide a reference for optimizing the spatial distribution of economic activities and a theoretical basis for synchronizing environmental protection with economic development in China.
Journal of Cleaner Production,1 April 2020
TianHu,JianPeng,YanxuLiu,JianshengWu*,WeifengLi,BingbingZhou
Abstract:The debate on land-sparing versus land-sharing has continued for decades regarding which of the two approaches can optimize the yield-conservation tradeoff. Current opinions are mostly criticisms for the overly-narrow focus on specific biodiversity conservation and simplistic solution to the agri-environmental scheme. This study based on limitations in previous studies aims to advance the land-sparing versus land-sharing strategies from two perspectives. First,an extended framework highlighting the tradeoffs between built-up land and green space in urban regions was proposed. Second, the multi-functionality of natural land was characterized by various ecosystem services rather than merely biodiversity. To demonstrate the applicability of the framework, a practical case of green space sparing -the Ecological Red Line (ERL) policy currently implemented across China-was elaborated. Particularly, soil retention was selected as a proxy to compare the difference between green space and unprotected areas. It showed that (1) the soil retention difference between areas inside and outside the ERL continued steady before the implementing of the ERL and thereafter presented upward trend. (2) the aggregate pattern and scale of soil retention changed obvious after the implementing of the ERL. (3) environment factors underlying the spatial variation of soil retention varied in inner and outer areas of the ERL, and the ERL might ameliorate soil retention of different land use types by spill-over effect. These findings demonstrated the effectiveness of the ERL, and further supported that the green space sparing is a promising strategy for urban land management. The ERL case study provides empirical evidence to support applications of the extended land-sparing versus land-sharing framework in urban regions.
Landscape ecology,FEB 2020
Jian Peng,Haoxi Lin,Yunqian Chen,Thomas Blaschke,Lingwei Luo,Zihan Xu,Yi’na Hu,Mingyue Zhao,Jiansheng Wu
Abstract:Context Urban agglomeration is an advanced spatial organization of cities, usually caused by urbanization processes when cities develop to a certain level - typically associated with higher population density and a certain density of built environment. However, compared with various studies focusing on specific cities, urban agglomerations are still understudied, especially for the quantitative identification of spatiotemporal evolution of urban agglomerations. Objectives This study aims to identify the boundary of urban agglomerations in China from 2000 to 2012, and to explore the temporal evolution and spatial difference of urban agglomerations. Methods Firstly, the core zone of urban agglomerations was identified using an appropriate threshold of the digital number (DN) of nighttime light. Secondly, the mean patch area and gravity model were used to determine the affected zone of urban agglomerations. Thirdly, spatiotemporal contrast was conducted focusing on the 23 main urban agglomerations in China. Results By 2012, the most highly developed Yangtze River Delta and Pearl River Delta urban agglomerations met the standard of world level, with the Beijing-Tianjin-Hebei urban agglomeration for regional level, as well as 11 urban agglomerations for sub-regional level. Regional differences in urban agglomerations between southern and northern China, or between coastal and inland China remained stable over the study period of 2000-2012. Compared with the western urban agglomerations, the outward expansion of eastern urban agglomerations decelerated. From 2000 to 2012, the overall development mode of urban agglomerations shifted from the core-expansion to the peripheral-development, together with slower expansion of urban agglomerations after 2006. Conclusions Nighttime light data are effective in exploring the spatiotemporal evolution of urban agglomerations.
62.Ambient PM2.5 and Annual Lung Cancer Incidence: A Nationwide Study in 295 Chinese Counties.
International journal of environmental research and public health,25 Feb 2020
Huagui Guo,Weifeng Li,*and Jiansheng Wu
Abstract:Most studies have examined PM2.5 effects on lung cancer mortalities, while few nationwide studies have been conducted in developing countries to estimate the effects of PM2.5 on lung cancer incidences. To fill this gap, this work aims to examine the effects of PM2.5 exposure on annual incidence rates of lung cancer for males and females in China. We performed a nationwide analysis in 295 counties (districts) from 2006 to 2014. Two regression models were employed to analyse data controlling for time, location and socioeconomic characteristics. We also examined whether the estimates of PM2.5 effects are sensitive to the adjustment of health and behaviour covariates, and the issue of the changing cancer registries each year. We further investigated the modification effects of region, temperature and precipitation. Generally, we found significantly positive associations between PM2.5 and incidence rates of lung cancer for males and females. If concurrent PM2.5 changes by 10 g/m3, then the incidence rate relative to its baseline significantly changes by 4.20% (95% CI: 2.73%, 5.88%) and 2.48% (95% CI: 1.24%, 4.14%) for males and females, respectively. The effects of exposure to PM2.5 were still significant when further controlling for health and behaviour factors or using 5 year consecutive data from 91 counties. We found the evidence of long-term lag effects of PM2.5. We also found that temperature appeared to positively modify the effects of PM2.5 on the incidence rates of lung cancer for males. In conclusion, there were significantly adverse effects of PM2.5 on the incidence rates of lung cancer for both males and females in China. The estimated effect sizes might be considerably lower than those reported in developed countries. There were long-term lag effects of PM2.5 on lung cancer incidence in China.
Cities,January 2020
JianshengWu,ZhaoFeng,XiwenZhang,YingyingXu,JianPeng
Abstract: Urban development requires the support of its surrounding areas. Accurate identification of urban hinterlands can help to scientifically evaluate strength and potential of urban development. The field strength model is regarded as an effective way to identify hinterlands, but the revision of friction coefficient has still not reached a consensus. With the application of big data in urban planning, it is possible to improve the field strength model. Toponym co–occurrence data, as a timely data source directly obtained from the Internet, can be used to reflect the spatiotemporal changes in urban connections, and provide an approach to quantifying the friction coefficient for the division of urban hinterlands. In this study, a new approach was developed by integrating toponym co–occurrence and improved field strength model. We considered the Pearl River Delta urban agglomeration as a case and identified the urban hinterland of each city. The results showed that the friction coefficient among cities fluctuated within a range of 1.25–2.50, the urban hinterlands were no longer confined to their own administrative divisions, and there was fierce competition with other cities. In particular, the urban hinterland of Guangzhou was 3699 km2 larger than its actual administrative area. In addition, the proposed approach was more reliable in urban hinterland identification compared with the traditional fixed friction coefficient method. This study provides an improved field strength model based on toponym co–occurrence, which can identify urban hinterlands more accurately and objectively as well as promote the application of big data in urban planning.
Science of The Total Environment,15 December 2019
JingSong, RuiYang,ZhengChang,WeifengLi,JianshengWu*
Abstract:Frequent and intensive urban flooding requires an extensive adoption of low-impact development (LID) to supplement traditional drainage infrastructures. Our study conceptualizes the resilient infrastructure framework with a particular reference to adaptation, an adjustment capacity in the social–ecological system to withstand various natural hazards and absorb negative impacts. We argue that adaption is an indicator for measuring LID effectiveness. A methodological framework is adopted using a time-dependent technique with a hydrodynamic inundation model to evaluate LID effectiveness. Results of a case study in Gongming, Shenzhen, China, show that LID projects can effectively reinforce adaptation capacity. However, spatial inequality and accumulation of different levels of adaptation are evident. This outcome is due to a relatively low absorption capacity because most areas will have a relatively high recovery capacity but retain a low absorption capacity with the construction of LID projects. A relatively mild increase in absorption capacity is due to the quality of man-made infrastructural development is conflicting across different areas of Gongming, for example some infrastructures are constructed by the government, whereas others by developers and villagers. In addition, the topographical factor makes some areas in Gongming lower-lying than others and is therefore increasingly vulnerable to urban flooding during rainstorms given the difficulty of discharging the surface runoff, thereby limiting the effectiveness of LID projects. Furthermore, the spatial inequality of adaptation improvement where LID projects cannot be evenly distributed within the research area leads to the unequal distribution of adaptation. These findings can confirm that the government can practically use adaptation as an indicator in evaluating LID effectiveness and identifying the problematic stages of drainage resilience in urban flooding risk mitigation.
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