Distribution patterns and traits of weed communities along an urban-rural gradient under rapid urbanization in Shanghai, China

2014 ◽  
Vol 15 (1) ◽  
pp. 27-41 ◽  
Author(s):  
Zhihui Tian ◽  
Kun Song ◽  
Liangjun Da
Keyword(s):  
Distribution Patterns ◽  
Rapid Urbanization ◽  
Weed Communities ◽  
Urban Rural

scholarly journals How Far Has China’s Urbanization Gone?

2018 ◽  
Vol 10 (8) ◽  
pp. 2953 ◽  
Author(s):  
Yiping Xiao ◽  
Yan Song ◽  
Xiaodong Wu
Keyword(s):  
Urban Development ◽  
Spatial Autocorrelation ◽  
Spatial Data ◽  
Spatial Association ◽  
Early Years ◽  
Spatial Data Analysis ◽  
Rapid Urbanization ◽  
Urban Rural ◽  
Global Spatial Autocorrelation ◽  
Over Time

China’s rapid urbanization has attracted wide international attention. However, it may not be sustainable. In order to assess it objectively and put forward recommendations for future development, this paper first develops a four-dimensional Urbanization Quality Index using weights calculated by the Deviation Maximization Method for a comprehensive assessment and then reveals the spatial association of China’s urbanization by Exploratory Spatial Data Analysis. The study leads to three major findings. First, the urbanization quality in China has gradually increased over time, but there have been significant differences between regions. Second, the four aspects of urbanization quality have shown the following trends: (i) the quality of urban development has steadily increased; (ii) the sustainability of urban development has shown a downward trend in recent years; (iii) the efficiency of urbanization improved before 2006 but then declined slightly due to capital, land use, and resource efficiency constraints; (IV) the urban–rural integration deteriorated in the early years but then improved over time. Third, although the urbanization quality has a significantly positive global spatial autocorrelation, the local spatial autocorrelation varies between eastern and western regions. Based on these findings, this paper concludes with policy recommendations for improving urbanization quality and its sustainability in China.

scholarly journals Decoupling forest characteristics and background conditions to explain urban-rural variations of multiple microclimate regulation from urban trees

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5450 ◽  
Author(s):  
Wenjie Wang ◽  
Bo Zhang ◽  
Lu Xiao ◽  
Wei Zhou ◽  
Huimei Wang ◽  
...  
Keyword(s):  
Light Intensity ◽  
Explanatory Power ◽  
Weather Conditions ◽  
Tree Density ◽  
Urban Trees ◽  
Lower Percentage ◽  
Air Cooling ◽  
Rapid Urbanization ◽  
Unit Distance ◽  
Urban Rural

Background Rapid urbanization in semi-arid regions necessitates greater cooling, humidifying, and shading services from urban trees, but maximizing these services requires an exact understanding of their association with forest characteristics and background street and weather conditions. Methods Here, horizontal and vertical air cooling, soil cooling, shading, and humidifying effects were measured for 605 trees from 152 plots in Changchun. Additionally, weather conditions (Tair, relative humidity, and light intensity), forest characteristics (tree height, diameter at breast height (DBH), under-branch height, canopy size, tree density, and taxonomic family of trees) and background conditions (percentage of building, road, green space, water, and building height, building distance to measured trees) were determined for three urban-rural gradients for ring road development, urban settlement history, and forest types. Multiple analysis of variance and regression analysis were used to find the urban-rural changes, while redundancy ordination and variation partitioning were used for decoupling the complex associations among microclimate regulations, forest characteristics, background street and weather conditions. Results Our results show that horizontal cooling and humidifying differences between canopy shade and full sunshine were <4.5 °C and <9.4%, respectively; while vertical canopy cooling was 1.4 °C, and soil cooling was observed in most cases (peak at 1.4 °C). Pooled urban-rural data analysis showed non-monological changes in all microclimate-regulating parameters, except for a linear increase in light interception by the canopy (r2 = 0.45) from urban center to rural regions. Together with the microclimate regulating trends, linear increases were observed in tree density, Salicaceae percentage, Tair, light intensity outside forests, tree distance to surrounding buildings, and greenspace percentage. Redundancy ordination demonstrated that weather differences were mainly responsible for the microclimate regulation variation we observed (unique explanatory power, 65.4%), as well as background conditions (12.1%), and forest characteristics (7.7%). Discussion In general, horizontal cooling, shading, and humidifying effects were stronger in dry, hot, and sunny weather. The effects were stronger in areas with more buildings of relatively lower height, a higher abundance of Ulmaceae, and a lower percentage of Leguminosae and Betulaceae. Larger trees were usually associated with a larger cooling area (a smaller difference per one unit distance from the measured tree). Given uncontrollable weather conditions, our findings highlighted street canyon and forest characteristics that are important in urban microclimate regulation. This paper provides a management strategy for maximizing microclimate regulation using trees, and methodologically supports the uncoupling of the complex association of microclimate regulations in fast urbanization regions.

scholarly journals Identifying Dynamic Changes in Ecosystem Services Supply and Demand for Urban Sustainability: Insights from a Rapidly Urbanizing City in Central China

2020 ◽  
Vol 12 (8) ◽  
pp. 3428 ◽  
Author(s):  
Zhengxin Ji ◽  
Yueqing Xu ◽  
Hejie Wei
Keyword(s):  
Ecosystem Services ◽  
Supply And Demand ◽  
Urban Sustainability ◽  
Well Being ◽  
Central China ◽  
Ecological Management ◽  
Dynamic Changes ◽  
Rapid Urbanization ◽  
Management Regime ◽  
Urban Rural

Identifying the balance and dynamic changes in supply and demand of ecosystem services (ES) can help maintain the sustainability of the regional ecosystem and improve human well-being. To achieve a sustainable ecological management regime in Zhengzhou City, this study presented a comprehensive framework for identifying dynamic changes of ES supply and demand and managing ES. Using land use data of Zhengzhou City in 1995, 2005, and 2015 and incorporating expert knowledge and the ES evaluation matrix, we evaluated the spatiotemporal changes in the ES supply and demand in Zhengzhou. Gradient analysis was conducted to identify urban–rural patterns in the budgets of ES supply and demand. Spatial autocorrelation analysis was employed to identify the hotspot areas of ES surpluses or deficits. The research results show the following: (1) In the past 20 years, the supply-and-demand relationship of ES in Zhengzhou has gradually evolved in a direction where supply falls short of demand. The average budget index of Zhengzhou’s ES supply and demand decreased from 7.30 in 1995 to −4.89 in 2015. Changes in the supply and demand status of ES in Zhengzhou corresponded to the background of rapid urbanization. (2) Urban–rural gradient differences exist in the budgets of ES supply and demand in Zhengzhou. Core development areas, such as the Zhengzhou urban areas, are in deficit, whereas a balance or surplus can be observed in rural areas far from urban centers. (3) The surplus hotspots of ES budgets were mainly distributed in the western and southern mountainous areas of Zhengzhou, and they were scattered and the scope shrank, with a decrease of 2.73 times in 20 years, whereas the deficit hotspots expanded outward with each urban area as the center, with an increase of 5.77%. Ecological management zoning (ecological conservation area, ecological improvement area, and ecological reconstruction area) with the effective guidance of ecological and economic policies could comprehensively improve ES management and achieve urban sustainability. The framework in this study can easily and quickly assess the supply and demand status of ES and provide scientific support for the ecological management in rapidly urbanizing areas.

scholarly journals Physician distribution across China’s cities: Regional variations

2020 ◽  
Author(s):  
Xuexin Yu ◽  
Wei Zhang ◽  
Jersey Liang
Keyword(s):  
Access To Health Care ◽  
Urban China ◽  
Limited Attention ◽  
Physician Density ◽  
Rapid Urbanization ◽  
Regional Variations ◽  
Urban Agglomerations ◽  
Urban Rural ◽  
Physician Distribution ◽  
Health Demand

Abstract Background Distribution of physicians is a key component of access to health care. Although there is extensive research on urban-rural disparities in physician distribution, limited attention has been directed to the heterogeneity across urban areas.This research depicts variations in physician density across over 600 cities in the context of China’s rapid urbanization. Methods Data came from National Census Surveys and China statistical yearbooks, 2000-2003, and 2010-2013. Cities were characterized in terms of not only administrative level but also geographic regions and urban agglomerations. We analyzed variations in physician supply by applying generalized estimating equations with an ordinal logistic linking function. Results Although overall physician density increased between 2003 and 2013, with population and socioeconomic attributes adjusted, physician density actually declined in urban China. On average, urban districts had a higher physician density than county-level cities, but there were regional variations. Cities in urban agglomerations and those outsides did not differ in physician density.Conclusion Despite the improved inequality between 2003 and 2013, the growth in physician density did not appear to be commensurate with the changes in population health demand. Assessment in physician distribution needs to take into account heterogeneity in population and socioeconomic characteristics.

Spatial patterns

2018 ◽  
Author(s):  
Philip James
Keyword(s):  
Spatial Distribution ◽  
Urban Environment ◽  
Distribution Patterns ◽  
Intermediate Disturbance Hypothesis ◽  
Urban Environments ◽  
Individual Species ◽  
Urban Forms ◽  
Intermediate Disturbance ◽  
Urban Rural ◽  
Disturbance Hypothesis

In this chapter, the discussion focuses on the spatial variation of species within urban environment. Studies on urban–rural gradients are discussed. These are studies along gradients of disturbance and environmental stress. The extreme heterogeneity of urban environments, where contrasting urban forms are juxtaposed, is recognized as an issue in drawing generalities. Despite this, some limited generalities in the patterns of species richness and density can be detected. The intermediate disturbance hypothesis is discussed and its limitations identified. Examples are presented from a number of taxa where different spatial distribution patterns are observed. There is also a brief consideration of r- and K-selected species and of urban avoiders and adaptors and how their distributions are affected by urban environments. While it is possible to make general statements regarding the distribution of biodiversity across an urban environment, considerable variations exist in terms of individual species.

scholarly journals Spatial Variation of Land Use/Cover Composition and Impact on Surface Urban Heat Island in a Tropical Sub-Saharan City of Accra, Ghana

2020 ◽  
Vol 12 (19) ◽  
pp. 7953
Author(s):  
Darshana Athukorala ◽  
Yuji Murayama
Keyword(s):  
Land Use ◽  
Urban Heat Island ◽  
Heat Island ◽  
Human Beings ◽  
Rapid Urbanization ◽  
Bare Land ◽  
Urban Rural ◽  
Urban Heat ◽  
The Mean ◽  
Sub Saharan

Rapid urbanization is one of the most crucial issues in the world of the 21st century. Notably, the urban heat island phenomenon is becoming more prominent in megacities and their hinterlands in temperate and subtropical climatic regions. In the daytime in summer, there exists a high possibility of accelerating the land surface temperature (LST) in desert cities, due to the alterations made by human beings in the natural environment. In this study, we investigate the spatial formation of LST in a tropical sub-Saharan city of Accra, a gateway to West Africa, using Landsat data in 2003 and 2017. Machine learning techniques and the different spatial and statistical methods such as tasseled cap transformation (TCT), urban-rural gradient, and multiresolution grid-based and landscape metrics were employed to examine procured land use/cover (LUC) and LST maps. LUC was classified into five categories: Built up, Green 1, Green 2, Bare land, and Water. The results of the analysis indicate that Built up, Green 2, and Bare land had caused the highest heating effect while Green 1 and Water had caused the considerable cooling effect during the daytime in Accra. The urban-rural difference in LST recorded 1.4 °C in 2003 and 0.28 °C in 2017. The mean size, mean shape, largest patch, and aggregation of Built up, Green 1, and Green 2 had a strong relationship with the mean LST. It is essential for urban planners to carefully examine the formation and effect of the urban heat island (UHI) for sustainable urban development and landscape policy toward mitigation and adaptation planning in Accra.

scholarly journals Resilience Thinking as a System Approach to Promote China’s Sustainability Transitions

2020 ◽  
Vol 12 (12) ◽  
pp. 5008
Author(s):  
Qirui Li
Keyword(s):  
Rural Areas ◽  
Mobility Control ◽  
Sustainability Transitions ◽  
Population Mobility ◽  
Policy Reforms ◽  
Rapid Urbanization ◽  
Resilience Thinking ◽  
Urban Rural ◽  
History Of ◽  
Urban And Rural Areas

Urban regeneration and rural revitalization are becoming major policy initiatives in China, which requires new approaches for sustainability transitions. This paper reviewed the history of policy reforms and institutional changes and analysed the main challenges to sustainability transitions in China. The urban-rural systems were defined as a complex dynamic social-ecological system based on resilience thinking and transition theory. The notions of adaptation and transformation were applied to compose a framework to coordinate “resilience” with “sustainability”. The findings indicate that China’s urbanization has experienced the conservative development of restructuring socio-economic and political systems (before 1984), the fast industrialization and economic development leaned to cities (1984 to 2002), the rapid urbanization led by land expropriation and investment expansion (2002 to 2012), and the quality development transformation equally in urban and rural areas (since 2012). The sustainability transitions have been challenged by controversial institutional arrangements, concerning population mobility control, unequal social welfare, and incomplete property rights. A series of policy interventions should be designed and implemented accordingly with joint efforts of multiple stakeholders and based on the combined technocratic and bottom-up knowledge derived from proactive and conscious individuals and collectives through context-dependent social networks.

scholarly journals Spatial evaluation of complex non-point source pollution in urban–rural watershed using fuzzy system

2013 ◽  
Vol 16 (1) ◽  
pp. 114-129 ◽  
Author(s):  
Haijun Wang ◽  
Wenting Zhang ◽  
Song Hong ◽  
Yanhua Zhuang ◽  
Hongyan Lin ◽  
...  
Keyword(s):  
Water Quality ◽  
Land Use ◽  
Point Source ◽  
Fuzzy System ◽  
Urban Areas ◽  
Rapid Urbanization ◽  
Nps Pollution ◽  
Urban Rural ◽  
Rural Place ◽  
The Impact

Non-point source (NPS) pollution has become the major reason for water quality deterioration. Due to the differences in the generation and transportation mechanisms between urban areas and rural areas, different models are needed in rural and urban places. Since land use has been rapidly changing, it is difficult to define the study area as city or country absolutely and the complex NPS pollution in these urban–rural mixed places are difficult to evaluate using an urban or rural model. To address this issue, a fuzzy system-based approach of modeling complex NPS pollutant is proposed concerning the fuzziness of each land use and the ratio of belonging to an urban or rural place. The characteristic of land use, impact of city center and traffic condition were used to describe spatial membership of belonging to an urban or rural place. According to the spatial membership of belonging to an urban or rural place, the NPS distributions calculated by the urban model and rural model respectively were combined. To validate the method, Donghu Lake, which is undergoing rapid urbanization, was selected as the case study area. The results showed that the urban NPS pollutant load was significantly higher than that of the rural area. The land usage influenced the pollution more than other factors such as slope or precipitation. It also suggested that the impact of the urbanization process on water quality is noteworthy.

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