Negative Effects Of Urbanization Research Articles

Weak effect of urbanization on bdelloid rotifers living in lichens.

Human activities have an overwhelming impact on the natural environment, leading to a deep biodiversity crisis whose effects range from genes to ecosystems. Here, we analysed the effect of such anthropogenic impacts on bdelloid rotifers (Rotifera Bdelloidea), for whom these effects are poorly understood. We targeted bdelloid rotifers living in lichen patches across urbanization gradients in Flanders and Brussels (Belgium). Urbanization was measured as the percentage of built-up area (BU) across different spatial scales, at circles from 50 to 3200 m of radius around the lichen. Urbanization effects on biodiversity were assessed on abundance, species richness and community-weighted mean body size of bdelloid rotifers, as well as on genetic diversity of a mitochondrial marker (cytochrome c oxidase subunit I) of one of the most common and widespread bdelloid species, Adineta vaga. Overall, no negative effect of urbanization was found at any diversity level and any spatial scale. Counterintuitively, the BU area quantified at the largest spatial scale had a positive effect on abundance. These results leave open the question of whether negative effects of urbanization are present for bdelloid rotifers, if they are mediated by other unexplored drivers, or if such effects are only visible at even larger spatial scales.

Thermo-mechanical behaviour of microbial induced carbonate precipita-tion (MICP) sand for geothermal pavements

Introduction
 Ground source heat pump (GSHP) or shallow geothermal energy systems are gaining attention for helping combat global warming and the negative effects of urbanisation caused by human activities. In recent decades, energy geo-structure techniques have developed by using subsurface infrastructures to exchange heat with the ground. These techniques can provide space heating and cooling while still preserving the primary structural function. As a result, they have become a valuable part of geothermal energy systems. Researchers have developed an understanding of incorporating ground heat exchangers into foundation piles, retaining walls, and tunnel linings with modest additional cost [1-4]. Pavements are also structures in contact with the ground that have the potential to be used as energy geo-structures (i.e., geothermal pavements), yet, their use has not been extensively studied [5-8].
 Soil thermal conductivity is an important factor influencing the efficiency of geothermal pavements since heat transfer in soils occurs primarily by conduction [9]. Microbially induced calcium carbonate (CaCO3) precipitation (MICP) is an innovative technique for strengthening sandy soils by coating and binding soil grains with calcium carbonate crystals. The distribution and arrangement of the CaCO3 within the pore spaces play a crucial role in determining the resulting strength of the treated sand. In addition, these crystals can act as thermal bridges to enhance the soil's thermal conductivity [10]. Combining geothermal pavements with MICP sand is still nascent, and the limited number of studies that exist mainly focus on the associated thermal property changes [11]. However, since the principal function of pavements is transmitting (dynamic) loads to the subbase and the underlying soil, the thermal conductivity of the MICP-treated pavement may vary as a result of the applied mechanical loads (e.g., due to the partial or total loss of thermal bridges and/or particle rearrangement). This research thus investigates the changes in the thermal conductivity of MICP-treated sands as they are subjected to quasi-static triaxial compression. The experimental results collected can deepen our understanding of the thermo-mechanical behaviour of MICP-treated sands and provide practical insights for using MICP to reinforce the subbase or underlying soil of geothermal pavements.
 Methodology
 This research performed a series of quasi-static triaxial tests on MICP-treated Houston sand, fine-grained, high-purity silica sand. Sporosarcina pasteurii (strain designation DSM 33) was used for the MICP treatment of the soil specimen. To study the effect of CaCO3 content on the thermo-mechanical performance of MICP-treated sand, three cementation solution treatment cycles were applied, yielding theoretical CaCO3 contents of 0.6%, 1.6% and 2.7% by weight, respectively. Details on the MICP treatment of the samples can be found in [12]. Samples for triaxial testing were treated in cylindrical tubes of 50mm inner diameter and 100mm height. To investigate the influence of the CaCO3 content on the soil thermal conductivity, MICP-treated specimens were air-dried prior to triaxial testing Triaxial tests were subsequently conducted in dry conditions to isolate the effect of the MICP and avoid the influence of water content on soil thermal conductivity (λ). Furthermore, a new miniaturised transient sensor was embedded in the triaxial samples to monitor the λ changes during the sharing phase [12].
 Results
 An example of the evolution of the deviatoric stress with axial strain under 50kPa confining stress (σ3) in the triaxial cell is shown in Figure 1a. Compared to the untreated sand, MICP-treated samples lead to higher peak strength and stiffness. Importantly, λ changes during triaxial testing for different CaCO3 contents are summarised in Figure 1b. Results indicate that the increase in CaCO3 content can significantly improve λ, and that λ rapidly decreases post-peak strength due to dilation and CaCO3 bond breakage. Once the samples reach its ultimate state, λ remains unchanged.

TWO NEW LOCALITIES FOR THE SPOTTED BETTA BETTA PICTA (VALENCIENNES 1846) (ANABANTIFORMES, OSPHRONEMIDAE) IN JAVA, INDONESIA

For the first time, the species Betta picta is registered for the southern part of Central Java (Indonesia), being recorded for two localities in the Progo River basin catchment, one in the Magelang and the other in the Bantul Regency, representing an extension of about 100km south to the nearest previously known distribution. These two new records were based on four specimens, three males and one female, collected in February 2019, which were identified as Betta picta since the males possess the main diagnostic features of the species: opercle with yellow-gold iridescence coloration, interrupted stripe below eyes, and a dark subdistal band on caudal and anal fins. Currently, this species is categorized as Near Threatened (NT) by the IUCN, and considering the negative effects of urbanization over the species natural habitats, the new records are important for the species conservation.

The effects of urbanization on pollinators and pollination: A meta-analysis.

Urbanization is increasing worldwide, with major impacts on biodiversity, species interactions and ecosystem functioning. Pollination is an ecosystem function vital for terrestrial ecosystems and food security; however, the processes underlying the patterns of pollinator diversity and the ecosystem services they provide in cities have seldom been quantified. Here, we perform a comprehensive meta-analysis of 133 studies examining the effects of urbanization on pollinators and pollination. Our results confirm the widespread negative impacts of urbanization on pollinator richness and abundance, with Lepidoptera being the most affected group. Furthermore, pollinator responses were found to be trait-specific, with below-ground nesting and solitary Hymenoptera, and spring flyers more severely affected by urbanization. Meanwhile, cities promote non-native pollinators, which may exacerbate conservation risks to native species. Surprisingly, despite the negative effects of urbanization on pollinator diversity, pollination service measured as seed set is enhanced in non-tropical cities likely due to abundant generalists and managed pollinators therein. We emphasize that the richness of local flowering plants could mitigate the negative impacts of urbanization on pollinator diversity. Overall, the results demonstrate the varying magnitudes of multiple moderators on urban pollinators and pollination services and could help guide conservation actions for biodiversity and ecosystem function for a sustainable future.

Negative effects of urbanization on plants: A global meta-analysis.

Understanding the response of plant diversity to urbanization is essential for conserving urban biodiversity. In this paper, a meta-analysis of 34 articles and 163 observations regarding the impact of urbanization on plant diversity was conducted. The results revealed that urbanization had marked negative effects on plants. Urbanization had positive effects on introduced species and negative effects on native species. In the subgroup analysis, we found that trees responded better to the effect of urbanization than herbs and shrubs. There was no evidence that urban size, population density, nighttime light, and GDP per capita had moderating effects on plant richness. Based on meta-regression analyses, native species in urban areas were less affected by urbanization at lower latitudes. Overall, urbanization had a marginally negative effect on plant abundance. The effects of urbanization on plant diversity during different stages of urban development were inconsistent. Our research shows that the suburbs play a crucial role in the urbanization gradient; there, plants survive with high species richness.

How urbanization affects residents' health risks: evidence from China.

Continued urbanization requires a deep understanding of how urbanization affects residents' health risks. This study used regression analysis of Chinese provincial-level panel data from 2004 to 2019 and empirically analyzed the nonlinear effects of urbanization on health risks and regional differences using STIRPAT model. Health risks were assessed by the average number of residents' visits to medical facilities and population mortality. We also examined the moderating effect of income and environmental factors. The results show that (1) urbanization increases the average number of residents' visits and reduces population mortality. The positive effect of urbanization in increasing the average number of visits is reinforced by an increase in income level and environmental pollution, whereas the negative effect of urbanization in reducing population mortality is weakened by environmental pollution. (2) Regarding long-term trends, urbanization has an N-shaped relationship with the average number of residents' visits, and a U-shaped relationship with population mortality; (3) Urbanization has an N-shaped relationship with the average number of residents' visits in the eastern, central, and western regions and an inverted N-shaped relationship with population mortality in the eastern region. Urbanization has significant effects on residents' health risks in areas with high levels of infrastructure. According to the results, suggestions are proposed, such as developing new-type urbanization, improving infrastructure, focusing on green urbanization, and promoting national fitness programs.

Spatial Relationships and Impact Effects between Urbanization and Ecosystem Health in Urban Agglomerations along the Belt and Road: A Case Study of the Guangdong-Hong Kong-Macao Greater Bay Area

A healthy ecosystem is fundamental for sustainable urban development. Rapid urbanization has altered landscape patterns and ecological functions, resulting in disturbances to ecosystem health. Exploring the effects of urbanization on ecosystem health and the spatial relationships between them is significant for cities along the "Belt and Road" aiming to achieve sustainable regional development. This study took the Guangdong-Hong Kong-Macao Greater Bay Area (GBA) as an example and measured the urbanization level (UL) and ecosystem health index (EHI) from 2000 to 2020 using multisource data. We used bivariate spatial autocorrelation, the geographically weighted regression model (GWR), and the optimal parameters-based geographical detector (OPGD) model to clarify the impact of urbanization on ecosystem health and the spatial relationship between them from multiple perspectives. The major findings of this study were: (1) the EHI in the GBA decreased significantly during the study period, dropping from 0.282 to 0.255, whereas the UL increased significantly, exhibiting opposite spatial distribution features; (2) there was a significant negative spatial correlation between UL and the EHI and significant spatial heterogeneity between high-low and low-high types in the GBA; (3) the negative effects of urbanization on ecosystem health were predominant and becoming more pronounced in the central GBA. Moreover, urbanization had an increasingly significant negative effect, leading to the deterioration of ecosystem health, in the central GBA. Population urbanization drove land urbanization, which became the main factor affecting ecosystem health in the GBA. Overall, urbanization had a significant negative effect on ecosystem health, with this impact being particularly prominent in the core urban junctions of the GBA, which require urgent attention. The results of the study provide a basis for decision making in the context of the steady urbanization and ecosystem health protection of cities along the "Belt and Road".

Urbanization and greenspace type as determinants of species and functional composition of collembolan communities

Urban regions are rapidly expanding worldwide resulting in biotic homogenization and loss of ecological functions in urban ecosystems due to management practices targeting at satisfying aesthetic and health demands of urban residents. These practices also modify living conditions and food recourses of soil invertebrates thereby affecting the structure and functional diversity of soil animal communities including collembolans. Here, we assessed the response of the community composition and functional diversity of collembolans as a major component of soil food webs to urbanization (suburban vs urban region) and greenspace types (including forest and four park-associated greenspaces: lawn, lawn with shrubs, lawn with trees, and lawn with shrubs and trees). Our results highlight that both urbanization and greenspace type significantly affect soil properties and community structure of collembolans. The negative effect of urbanization and park-associated greenspaces on species and functional composition of collembolan communities were likely due to both changes in soil abiotic conditions and bacterial community composition, whereas the reduction of collembolan functional traits likely resulted from changes in soil abiotic conditions and fungal community composition. In park-associated greenspaces richness and diversity of bacterial communities were highest in lawns with trees and lowest in forests. By contrast, species richness and diversity of fungal communities were highest in lawns with shrubs, but, similar to bacteria, lowest in forests. Community composition and functional traits of collembolans were more homogeneous in urban than suburban greenspaces pointing to reduced functioning of collembolan assemblages in urban areas. Overall, our results suggest that changes in soil properties and bacterial communities caused by urbanization and greenspace type are important factors contributing to taxonomic homogenization of collembolan communities, while the loss of functional traits of collembolan communities in urban greenspaces is likely caused by changes in soil properties and fungal community composition.

Spatio-temporal evolution and driving factors of eco-environmental quality based on RSEI in Chang-Zhu-Tan metropolitan circle, central China

Accurately analyzing the spatial and temporal evolution of regional eco-environmental quality and exploring the response of eco-environmental quality to natural environment and human factors are essential to protect the regional ecological environment. This study analyzed the ecological environmental quality of Chang-Zhu-Tan metropolitan circle, central China from 2000 to 2020 based on Google Earth Engine (GEE) and Remote Sensing Ecological Index (RSEI). Subsequently, we introduced the Partial Least Squares Structural Equation Model (PLS-SEM) to explore the response of RSEI to the direct and indirect effects of natural and anthropogenic factors, and assessed the spatial autocorrelation of regional ecological environmental quality. The results showed that the mean value of RSEI in the study area was showing an increasing trend, with the lowest mean value of RSEI in 2010 (0.6508) and the highest mean value of RSEI in 2020 (0.6948). The eco-environmental quality level was mainly good and excellent, and the average area accounted for more than 70% of the total area, and showed an upward trend during 2000–2020. Climate, soil, terrain, and urbanization had different effects on the ecological environment, with climate, soil, and terrain had positive effects on the ecological environment, while urbanization had negative effects on it. The positive effect of climate on ecological environment was gradually weakened, while the negative effect of urbanization on ecological environment was gradually strengthened. Climate and urbanization weakened the positive effect of soil and terrain in different degrees. This study provides a method for rapid and accurate assessment of regional eco-environmental quality and exploration of complex interaction pathways of influencing factors, which is essential for balancing the relationship between regional development and nature.

Spatial and temporal dynamics of habitat quality in response to socioeconomic and landscape patterns in the context of urbanization: A case in Zhengzhou City, China

With the rapid development of urbanization, the habitat quality (HQ) in urban areas has been eroded. This phenomenon is destroying the balance of ecosystems, triggering the reduction of biodiversity and the decay of ecosystem service functions. The study of the relationship between urbanization and HQ in Zhengzhou City is beneficial for the reference of sustainable urban ecological planning and management. Based on landscape classification data and socioeconomic data for three years, this study analyzes the spatial correlations between socioeconomic and landscape pattern factors and HQ, compares the dynamic changes in the explanatory power of different factors, and explores the joint effects between multiple factors. The results show that: (1) The overall value of HQ index in Zhengzhou City decreased by .10 during 2000–2020, mainly occurring in suburban areas, with a small amount of HQ improvement occurring in the core areas of ecological protection, such as mountains and river channels. (2) The spatial autocorrelation of all influencing factors with HQ increased during this period, while the negative impact from socio-economic sources was stronger than the positive impact from landscape patterns. (3) Intensive human activities lead to a single habitat type, which reduces HQ; rich landscape types and complex landscape composition can enhance HQ. Improving the connectivity of blue-green landscapes helps to attenuate the negative effects of urbanization on HQ. (4) Changes of HQ in the study area and the development of multi-factor effects on HQ are driven by the Zhengzhou Metropolitan Area Plan. Urban development policies and management can build idyllic complexes at the edge of urban development, preserving pristine blue-green patches to avoid their homogenized distribution and thus slowing the decline of HQ. The above results provide new ideas for the development of sustainable urban ecology.

The influence of Smart City development in Romania on the financial management of local authorities

"Smart City's role is to improve urban life through sustainable integrated solutions and address city-specific challenges in various policy areas, such as energy, mobility and transport, and ICT, which must also be effectively implemented. Smart City relies on the use of information and communication technology (ICT) to sustainably develop urban spaces and limit the negative effects of urbanization. Globally, there is a trend to promote the concept of Smart City as a solution for urban areas in efficient and sustainable development, without affecting the environment. In Romania, Smart City has become a concern for local, urban and rural administrations, in the context in which at European level there are non-reimbursable funds for such projects. In Romania, Smart City and the projects that have the role of making an administration to be Smart are in their infancy. The purpose of this article is to highlight the advantages of Smart City development in urban administrations in Romania and the influence on the financial management of local authorities. Urban spaces in Romania face certain difficulties, both in terms of development (economic, infrastructure), but also pollution. The paper will highlight the stage of development of Smart City and how it influences the financial management of local governments, where such projects are implemented. The paper is descriptive, by correlating the information highlighted in the literature and data on projects submitted for Smart City by urban areas in Romania. The study analyzes the projects submitted by the main urban areas in Romania in 2020 for their development as Smart City, according to the website https://steinbeis-romania.com, thus highlighting the concern of local governments for their development as Smart City. "

The Compact City - Measuring Urban Sprawl Using GIS and Landscape Metrics: Case Study: The City of Kaçanik - Kosova

It is thought that the compact city is the best goal to prevent or reduce the negative effects of urbanization on the environment. Therefore, this work focuses on the use of controlled urban planning parameters and zoning parameters, during the drafting of the urban development plan in Kosovo, which in most cases are ignored. The aim of this paper is to find a way to develop compact and sustainable cities in Kosovo, and is based on quantitative research. The paper evaluates the built area within “urban zones” in order to identify the expansion tendencies of settlements, with the aim of contributing to preventing future uncontrolled developments. Additionally, land use should be in full compliance with spatial plans, both national and local. In this case, the treatment of the city of Kaçanik was taken as an example for Kosovo's conditions, based on the demographic potential, intensity of land use, style of construction, with the implementation of the zoning parameters, showing the way of land use, which should be in harmony with the concepts of sustainable development.

Environmental Effects of City–County Mergers in China: Strengthening Governance or Aggravating Pollution?

Green and high-quality development is the focus of China’s urban development strategy in the new era. The city–county merger policy has been one of several powerful tools used by the Chinese government to promote urbanization in recent decades, but whether and how it influences the environment has been rarely discussed. Using the multi-period difference-in-differences method and urban panel datasets, we investigated the environmental effects of the city–county merger policy in China from 2000–2016 and obtained the following results. First, the city–county mergers significantly reduce the environmental pollution of merged cities. The robustness tests support this conclusion. Second, the effects of city–county mergers on environmental pollution control decrease with the increase in geographical distance between the merged cities and counties; the smaller the differences in economic strength of merged cities and counties, the better the coordinated control of environmental pollution; the environmental governance effects of merged cities in the eastern region are lower than those in the central and western regions. Third, by intensifying the vertical management of urban environmental protection agencies, unified urban planning and fiscal centralization, the city–county mergers can strengthen the overall environmental governance capabilities of merged cities, reduce the negative effects of urbanization, and ultimately improve the environmental quality.

Urbanization intensifies tree sap flux but divergently for different tree species groups in China.

In recent years, positive and negative effects of urbanization on forest ecosystem have been reported by many studies, while some uncertainties about the impact of urbanization-induced spatial heterogeneity of environmental factors on forest systems still remain unclear. In this study, we analyzed the urbanization effects on sap flux of a common subtropical evergreen tree species Schima superba along an urban-rural gradient in Guangdong Province, South China, and identified the consistency of these results among different groups (evergreen, deciduous, and coniferous species) using data from 83 previously published studies in China. The mean sap flux density (Fd) of S. superba in Xiaoqingshan (XQS), Heshan (HS), Dinghushan (DHS), and Shimentai (SMT), along the urban-rural gradient was 40.9gm-2s-1, 32.1gm-2s-1, 17.0gm-2s-1, and 17.5gm-2s-1, respectively, presenting a decreasing trend with the diminishing urbanization. This pattern in Fd tended to enlarge with tree size and was well confirmed by the enhanced leaf transpiration rate (by 119%) and photosynthetic rate (by 8.8%) for the S. superba in another urbanization gradient from the urban (Hangzhou, denoted as "HZ") to rural sites (Jiande, denoted as "JD") in Zhejiang Province, East China, which has similar climatic condition and urbanization with Guangdong Province. We attributed such positive effects to the decreased sapwood density and specific leaf area (SLA), as well as the increased Huber value (sap wood area/leaf area) and the sap wood specific hydraulic conductivity (KS). We also found that pollutant emission exerted more impact on Fd than climatic factors change, since the variation of the latter was not large enough to cause significant change of Fd under the same climatic zone. In addition, we conducted a principal component analysis (PCA) based on the published 83 studies. Results showed Fd of evergreen tree species was related positively to principle 1 and negatively to principle 2, respectively, whereas the Fd of deciduous broadleaf and coniferous tree species was positively and negatively related to both principles, respectively. This study demonstrated the potential impact of urbanization-related pollutant emission changes on water use of forest trees and the growth among different groups.

Житлове будівництво в Україні у контексті урбаністичних та демографічних змін

It is substantiated within the article that the course of urban processes, high level of mortality, migration, income diff erentiation of the population of Ukraine aff ects housing construction, housing sector, as the number of urban residents is declining more slowly than the number of residents of small cities, villages and settlements due to a lower level of natural population decline and migratory growth, stimulating the demand for housing in cities. Th e purpose of the article is to systematize the factors of interaction of housing construction, demographic and urban processes in Ukraine, and substantiate the corrective measures of housing policy to prevent the negative eff ects of urbanization. Th e scheme of the impact of the processes of urbanization, natural increase of the population of the need satisfaction for habitation on housing construction is developed. In the process of using the questionnaire method, it is substantiated that the level of satisfaction of needs (including housing needs) in rural areas is much lower than in the city. Th e study made it possible to conclude that with declining incomes of population, sales of country houses are declining; studio-apartments and one-and two-bedroom apartments are beginning to be in greater demand in new buildings. It is determined that meeting the need for housing involves solving such tasks as: increasing the volume of housing construction, reducing the failing housing stock, carrying out quality overhaul of housing, development of the mortgage market and rental market, etc. Measures to stimulate housing construction and housing repair as a corrective factor in the equalization of urban processes in Ukraine in order to reduce the environmental burden on megapolis, cities, as well as equalizing the level of population density in Ukraine are developed. It is argued that within the program of social responsibility of construction business, it is advisable to stimulate construction companies, to repair failing housing at the state level with the establishment of standards individually for rural and urban areas with the active use of legal, financial instruments, state subsidies to developers, who implement projects on the development of urban and rural areas to reimburse the costs of repairs, redevelopment of failing housing.

Stormwater Treatment Effectiveness of Established Lined Bioretention Facilities in Portland, Oregon

Bioretention systems are commonly used to treat and detain stormwater runoff and help mitigate many negative effects of urbanization. The goal of this project is to assess the pollution reduction effectiveness of lined bioretention facilities that have been in use and functioning for four to eight years. Lined bioretention facilities are installed with an impermeable liner below the facility to prevent exfiltration of stormwater into the surrounding soil. Grab samples were taken from seven facilities in Portland, Oregon, over a two-year period to measure the quality of stormwater flowing into and out of the facilities. Results showed decreased concentrations of total suspended solids (TSS; 94%), ammonia (85%), total copper (59%), total zinc (80%), and dissolved zinc (41%). However, the facilities were found to increase levels of nitrate (2,070%) and orthophosphate (141%) in the outflow. Based on this study, effective TSS removal by bioretention facilities does not necessarily equate to equally effective treatment of other pollutants (especially orthophosphate and nitrate). Additional research is necessary to determine the significance of the observed increase in nutrients, understand the underlying mechanisms, and test possible design modifications to improve nitrate and orthophosphate removal.

Urbanisation drivers and underlying mechanisms of terrestrial insect diversity loss in cities

1. Urbanisation is one of the main land‐use changes behind global insect collapse. Despite that previous studies have described the negative effects of urbanisation on insect communities, so far there is no synthesis that considers multiple urban drivers, their combined effects, and the role of species traits altogether.2. Here we developed an integrative framework of the underlying mechanisms behind terrestrial insect species loss in cities by exploring five leading drivers: impervious surfaces, habitat fragmentation, urban heat island, pollution, and exotic plants. For each driver, we identified the main direct and indirect (mediated through species interactions or changes in resources) effects on insect populations and communities, emphasising the role of species traits as moderators of such effects.3. Body size, mobility, and oviposition/nesting requirements were the traits that frequently defined insect vulnerability to urban drivers. Urban heat island and pollution deserve further research from a community‐level approach. Direct effects of drivers dominated the literature, while most indirect paths were mediated by changes in resources rather than species interactions.4. In conclusion, our review showed the challenges of recognising particular effects and mechanisms for each urban driver and their combined effects. By doing so, we intended to encourage researchers to address some of the gaps we noticed in order to fully understand how urbanisation is affecting insect communities. Finally, we outlined the main recent urban planning strategies and future challenges in order to successfully conserve urban insect biodiversity.

Environmental Kuznets Curve Hypothesis on CO2 Emissions: Evidence for China

China is the largest CO2 emitter in the world, and it shared 28% of the global CO2 emissions in 2017. According to the Paris Agreement, it is estimated that China’s CO2 emissions will reach its peak by 2030. However, whether or not the CO2 emissions in China will rise again from its peak is still unknown. If the emission level continues to increase, the Chinese policymakers might have to introduce a severe CO2 reduction policy. The aim of this paper is to conduct an empirical analysis on the long-standing relationship between CO2 emissions and income while controlling energy consumption, trade openness, and urbanization. The autoregressive distributed lag (ARDL) model and the bounds test were adopted in evaluating the validity of the Environmental Kuznets Curve (EKC) hypothesis. The quantile regression was also used as an inference approach. The study reveals two major findings: first, instead of the conventional U-shaped EKC hypothesis, there is the N-shaped relationship between CO2 emissions and real gross domestic product (GDP) per capita in the long run. Second, a positive effect of energy consumption and a negative effect of urbanization on CO2 emissions, in the long run, are also estimated. Quantitatively, if energy consumption rises by 1%, then CO2 emissions will increase by 0.9% in the long run. Therefore, the findings suggest that a breakthrough, in terms of policymaking and energy innovation under China’s specific socioeconomic and political circumstances, are required for future decades.

The impact of urbanization on body size of Barn Swallows Hirundo rustica gutturalis.

Urbanization implies a dramatic impact on ecosystems, which may lead to drastic phenotypic differences between urban and nonurban individuals. For instance, urbanization is associated with increased metabolic costs, which may constrain body size, but urbanization also leads to habitat fragmentation, which may favor increases in body mass when for instance it correlates with dispersal capacity. However, this apparent contradiction has rarely been studied. This is particularly evident in China where the urbanization process is currently occurring at an unprecedented scale. Moreover, no study has addressed this issue across large geographical areas encompassing locations in different climates. In this regard, Barn Swallows (Hirundo rustica) are a suitable model to study the impact of urbanization on wild animals because they are a widely distributed species tightly associated with humans. Here, we collected body mass and wing length data for 359 breeding individuals of Barn Swallow (H. r. gutturalis) from 128 sites showing different levels of urbanization around the whole China. Using a set of linear mixed‐effects models, we assessed how urbanization and geography influenced body size measured using body mass, wing length, and their regression residuals. Interestingly, we found that the impact of urbanization was sex‐dependent, negatively affecting males’ body mass, its regression residuals, and females’ wing length. We also found that northern and western individuals were larger, regarding both body mass and wing length, than southern and eastern individuals. Females were heavier than males, yet males had slightly longer wings than females. Overall, our results showed that body mass of males was particularly sensitive trait to urbanization, latitude, and longitude, while it only showed a weak response to latitude in females. Conversely, while wing length showed a similar geographical pattern, it was only affected by urbanization in the case of females. Further research is needed to determine whether these phenotypic differences are associated with negative effects of urbanization or potential selective advantages.

Urbanization and plant invasion alter the structure of litter microarthropod communities.

Anthropogenic activity underpins the creation of urban ecosystems, often with introduced or invasive species playing a large role in structuring ecological communities. While the effects of urbanization on charismatic taxa such as birds, bees or butterflies have received much attention, the impacts on small and inconspicuous organisms remain poorly understood. Here, we assess how the community structure of leaf litter-inhabiting microarthropods in city parks varies along an urbanization gradient in Toronto, Canada. At each park, we established paired forest understorey plots which were either dominated by native vegetation or dog-strangling vine Vincetoxicum rossicum, an invasive species that is spreading throughout northeastern North America and abundant in urban areas. We compared microarthropod richness, abundance and diversity in ecological traits between invaded and non-invaded plots as well as compositional dissimilarities among plots across the urbanization gradient. We recorded 123 genera and found (a) there was a negative effect of urbanization on microarthropod richness and abundance but only in invaded plots; (b) richness and abundance increased continuously with urbanization in non-invaded plots, but peaked at intermediate urbanization levels in invaded plots and (c) there was significant turnover with increasing urbanization, with distinct communities represented in highly urbanized areas compared to less urbanized areas, regardless of whether invaded. We also found litter microarthropod richness and abundance increased with soil ammonium and decreased with nitrate. These trends were especially strong for fungivorous microarthropods; however, there was no relationship between soil nutrients and urbanization or invasion. Urbanization and biological invasion drive biodiversity change, and there is a need to disentangle these effects on ecological communities and related ecosystem processes. We show microarthropod communities change with urbanization, with the effects of invasion most prominent in non-urban areas. Here, there is high richness and abundance but low ecological trait diversity, possibly because certain feeding traits are excluded and others overrepresented. Understanding of urban ecological systems must include knowledge of the microarthropods that interact widely across food webs, form distinct communities in highly urban areas and drive many of the important ecological functions upon which people in cities depend.