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Urban trees perform various ecosystem services, and tree DBH (trunk diameter at breast height, 1.3 m above the ground) can act as a surrogate measure of these important functions. However, DBH has seldom been studied in relation to spatial variation, possible underlying drivers, and response to urbanization. Our field investigation collected data from tree species within Urban Function Units (UFUs) in south China's coastal city Zhanjiang, which has recently experienced rapid urbanization. The land cover of UFUs was determined by visual interpretation of satellite images. Trees with DBH > 2 cm were assessed, and vines were excluded. We recorded 12,434 trees in the green space belonging to 185 species, 137 genera, and 51 families. The dominant DBH range, 5‒15 cm, accounted for 43.72% of the total stems. The DBH of 33 individuals exceeded 90 cm, 20 of which were Ficus species. At 32.39 cm, the average DBH in commercial areas was the highest among the UFU types, while woodlands had the lowest at 7.11 cm. GLMM analysis showed that UFU types, landscape configuration, land cover, and construction age were all significantly associated with tree DBH. Tree DBH had a significant positive correlation with impervious surface area and a negative correlation with green space surface area. The largest trees were mainly distributed in urban villages, schools, parks, and transportation areas. Understanding urban tree DBH structure and its related factors can promote sustainable urban-forest development and management. [ABSTRACT FROM AUTHOR]

This study utilized the OLS and Quantile regression approach to investigate the relationship between stock prices and exchange rate. Monthly data of exchange rate and stock market of Pakistan, China, Russia and Turkey from March, 2003 to July, 2017 have been used. For data of stock market major stock indices are used and currency exchange rate of country with respect to US dollar are used. The paper checked the stationarity of the series through ADF test as well as PP test and Engle & Granger to check the long run relationship. It is observed that none of the country exhibit long run equilibrium between exchange rate and stock prices. Results are same under two different methods of ordinary least square and Quantile regression. Both models show that coefficient of China is negative, which support the presence of portfolio balance effect in China. Results demonstrate that stock prices (SP) and exchange rate (EX) have asymmetric relationship as coefficients vary under different quantiles. [ABSTRACT FROM AUTHOR]

About 52% of the world's population now lives in urban areas, and 41% of urban land in developed countries is used for residential areas. The amount and quality of residential green space, an important element in urban residential infrastructure, is closely correlated to city dwellers' quality of life. The quality of green spaces is not only closely correlated to the ecosystem services they provide, but also to their disservices. In order to (i) examine how plant diversity and plant traits vary in different residential areas, (ii) determine the main socio-economic factors driving plant trait variations across different residential areas, and (iii) provide an overview on selected ecosystem services and disservices related to plant diversity, we investigated the flora and socio-economic properties of 83 residential areas in Beijing, China. We found a total of 369 plant species belonging to 99 families and 150 genera. With respect to plant traits, there were 90 annual species, 174 alien species, 169 pollen allergenic species, and 133 species with edible or pharmaceutical value. The number of perennial, alien, ornamental and edible plant species was largest in residential areas completed in the 1990s. The number of allergenic species was highest in residential areas completed prior to 1980. The Simpson, Shannon and Pielou indices for trees and shrubs were highest in areas completed in the 1990s, while those same indices for herbs were highest in residential areas completed prior to 1980. General Linear Model analyses revealed that richness increased with increasing housing price across all groups of species. Principal Component Analysis indicated that housing price and floor-area ratio are the variables that positively correlate with species richness for all groups of species. [ABSTRACT FROM AUTHOR]

As a result of high-density urbanization and climate change, both the frequency and intensity of extreme urban rainfall are increasing. Drainage systems are not designed to cope with this increase, and as a result, floods are becoming more common in cities, particularly in the rapidly growing cities of China. To better cope with more frequent and severe urban flooding and to improve the water quality of stormwater runoff, the Chinese government launched the national Sponge City Construction (SCC) program in 2014. The current SCC design standards and guidelines are based on static values (e.g., return periods, rainfall intensities, and volume capture ratio (VCR)). They do not fully acknowledge the large differences in climate conditions across the country and assume that the hydraulic conditions will not change over time. This stationary approach stems from the traditional engineering approach designed for grey infrastructure (following a "one size fits all" approach). The purpose of this study was to develop a methodology to assess the VCR baseline (before construction in the pre-development stage) and changes in VCR (difference between the VCR of the pre- and post-development stage). The VCR of the post-development stage is one of the required indicators of the Assessment Standard for Sponge Cities Effects to evaluate SCC projects. In this study, the VCR was derived from remote-sensing-based land use land cover (LULC) change analysis, applying an unsupervised classification algorithm on different Landsat images from 1985 to 2015. A visualization method (based upon Sankey chart, which depicts the flows and their proportions of components) and a novel and practical partitioning method for built-up regions were developed to visualize and quantify the states and change flows of LULC. On the basis of these findings, we proposed a new indicator, referred to as V C R a - L , in order to assess the changes in urban hydrology after SCC construction. This study employed the city of Nanjing as a case study and analyzed detailed information on how LULC changes over time of built-up areas. The surface area of the urban and built-up areas of Nanjing quadrupled from 11% in 1985 to 44% in 2015. In the same period, neither the entire city nor its subregions reached the VCR target of 80%. The proposed new methodology aims to support national, regional, and city governments to identify and prioritize where to invest and implement SCC measures more effectively in cities across China. [ABSTRACT FROM AUTHOR]

Understanding the factors that drive green space composition and richness in heterogeneous urban landscapes is critical for maintaining important ecosystem services and biodiversity. Few studies have been conducted on urban greening and plant diversity at the urban functional unit (UFU) level, although a handful of studies have explored the drivers of greening percentage and its relationships with plant richness in tropical cities. In this study, we conducted field surveys, compiled census and remote sensing data, and performed spatial analyses to investigate the interrelationship between greening percentages, plant diversity, and the socioeconomic variables of different primary and secondary UFUs in the cities of Beijing, Zhanjiang, and Haikou in China. We found that these relationships did not differ significantly between primary and secondary UFUs, and that Parks represented the largest areas of forested land, grassland, and water bodies across all three cities. Moreover, the greening percentages of all UFUs across these three cities were positively correlated with both socioeconomic variables and plant species richness. These relationships can be utilized to guide future green space planning within urban ecosystems. [ABSTRACT FROM AUTHOR]

Cultivating a deeper understanding of the response mechanism of cultural ecosystem services to urbanization is increasingly recognized as a critical component of sustainable governance and land-use decision making. However, except for a range of studies exploring changes in ecosystem services during urbanization that address cultural ecosystem services as merely one service type, few investigations reveal the changing mechanism of cultural ecosystem services in rapid urbanization. To fill this knowledge gap, this study selected Changyang Township, Fangshan District, Beijing as a case to understand the influence of intense urbanization on changes in cultural ecosystem services in the context of Chinese cities. Cultural ecosystem services were classified and mapped based upon a systematic and critical review of previous literature, field surveys, and kernel density analysis. The influence of urbanization on cultural ecosystem services' changes was examined through casual loop diagrams. Urbanization was found to contribute positively to cultural ecosystem services in general, although a reconstruction process revealed that these were initially diminished and then revamped during China's urbanization. The primary development of the land was the key factor contributing to the process by which conventional cultural ecosystem services deteriorated during urbanization, while spatial planning and design facilitated the reconstructions of cultural ecosystem services across larger core areas. Meanwhile, cultural ecosystem services were experienced differently by residents in areas with varied urbanization intensities. This study provides an in-depth analysis and suggestions for primary land development in the Chinese context to achieve sustainable urbanization concerning cultural ecosystem services. In addition, this study enriches the cultural ecosystem services literature from a dynamic lens while highlighting the complexity of recreation as both an experience and a component of cultural ecosystem services. • Urbanization is found to play both negative and positive roles in changing CESs. • There was a destruction and reconstruction process of CESs during urbanization. • Land preparation was the key factor in CESs destruction, and park design represented CESs reconstruction. • Recreation was found to be both a way of experiencing CESs and a component of CESs. [ABSTRACT FROM AUTHOR]

The impact of human activities on terrestrial ecosystems is becoming more intense than ever in history. Human disturbance analyses play important roles in appropriately managing the human-environment relationship. In this study, a human disturbance index (HDI) that uses land use and land cover data from 1980, 2000, 2010, and 2018 is proposed to assess the human disturbance of ecosystems in the Guangdong-Hong Kong-Macao Greater Bay Area. The HDI is first calculated by classifying the human disturbance intensity into seven levels and 13 categories from weak to strong in ecosystems. Then the driving factors of the HDI spatial pattern change are explored using a geographically weighted regression (GWR) model. The results showed that the spatial pattern of the HDI was high in the middle and low in the surrounding areas. The intensity of human disturbance increased, and the medium and high disturbance areas expanded during 1980-2018, especially in Guangzhou, Foshan, Shenzhen, and Dongguan. Human disturbance displayed an obvious spatial heterogeneity. The GWR model had a better explanation effect of the analysis of the HDI change drivers. The driving effect of the socioeconomic conditions was significantly stronger than that of the natural environmental. This study assists in understanding the distribution and change characteristics of the ecological environment in areas with strong human activities and provides a reference for related studies., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)