Urban-rural Gradient Research Articles

Environmental and social impacts of shifting park-use patterns during the COVID-19 pandemic: Insights from state and local park managers

Parks and protected areas offer a variety of ecosystem services and promote opportunities that enhance human health and well-being. However, these benefits may be jeopardized when overcrowding degrades environmental and social conditions in parks. The COVID-19 pandemic is assumed to have been associated with substantial increases in visitation to parks and protected areas, but patterns in use and degradation varied by site type (e.g., state versus local parks; urban versus rural). In this study, we aimed to understand how changing recreational use patterns during the COVID-19 pandemic impacted parks, and how those changes differed between state and local parks across urban-rural gradients. We distributed a survey asking state park superintendents (n = 36) and local park managers (n = 84) in the state of North Carolina to estimate the extent of environmental and social impacts in their parks both before and during the pandemic. We discovered that, based on managers’ responses, state parks were approximately 12 times more likely to experience heightened environmental impacts and 23 times more likely to experience heightened social impacts than local parks during the pandemic, even when controlling for impact levels prior to the pandemic. We found no significant differences between urban and rural parks. These findings suggest regional parks may be the most vulnerable to environmental and social disturbances during times of heightened visitation, and thus highlight a need for both more resources and more attention to governance issues for these parks. Management implicationsThis study found that state parks in North Carolina experienced more frequent social and environmental impacts, both before and during the COVID-19 pandemic, compared to local parks. This highlights the need to explore measures that can maintain state parks as sources of resilience and recovery during future crises while mitigating park impacts. Proposed strategies include:•Directing park usage to more resilient areas.•Establishing strategic partnerships between parks to enhance capacity.•Education and outreach to minimize visitor impacts.•Establishing emergency funds for parks most likely to be impacted during times of heightened visitation.•Expanding accessible greenspace in anticipation of increased visitation.

Soundscapes in Urban Green Spaces of a Megacity Across an Urban–Rural Gradient: A Case Study of Shanghai

Urban soundscapes are valuable indicators of urban biodiversity and ecosystem health. This study investigated the spatial and temporal characteristics of soundscapes in megacity green spaces and their relationship with the urban environment. An acoustic index was formulated and calculated using long-term data from Shanghai’s urban green spaces. The results show a significant increase in the acoustic index during spring and summer, peaking during these periods, while a decrease was observed from December to February, dominated by abiotic sounds. Diurnal variations indicate a rapid increase in the acoustic index at sunrise, reflecting heightened avian activity during the dawn chorus. Human interference in the urban center limited acoustic activity, whereas the outer suburbs, with their more natural environments, supported greater acoustic richness.

The diversity and nesting preferences of birds along an urban-rural gradient in the Kathmandu Valley, Nepal

The diversity and nesting preferences of birds along an urban-rural gradient in the Kathmandu Valley, Nepal

Attributes of private yards along a rural-urban gradient in China highlight opportunities and limits to increase trees to benefit biodiversity and climate

Attributes of private yards along a rural-urban gradient in China highlight opportunities and limits to increase trees to benefit biodiversity and climate

Spatial patterns and driving factors of plant diversity along the urban-rural gradient in the context of urbanization in Zhengzhou, China.

Plant diversity is the basis for human survival and development, directly affecting the function and stability of urban ecosystems. Its distribution pattern and causes have been a central issue in ecological and landscape gardening research. Rapid urbanization in Zhengzhou City has led to the fragmentation of urban green spaces and damage to ecosystems, seriously affecting urban biodiversity conservation. Understanding the distribution pattern of plant diversity in the region and its relationship with environmental factors is crucial for maintaining and enhancing urban plant diversity. Plant data from 178 sample plots in the built-up area of Zhengzhou City were collected and combined with environmental factors, and the characteristics of plant diversity, richness patterns, and their main environmental explanations in Zhengzhou City were explored. Results showed that there were 596 plant species belonging to 357 genera and 110 families in the study area. There were five dominant families and four dominant genera. Four distinct spatial patterns of plant diversity were identified along the urban-rural gradient. Urbanization factors such as GDP per capita, house prices, and imperviousness within 500 m from the patch significantly influenced plant diversity. There was an imbalance between the spatial pattern of plant diversity and application of urban landscape greening in Zhengzhou City. Future studies should focus on the application of native plants, curb plant homogenization, and reduce anthropogenic interference, which are conducive to protecting and enhancing urban plant diversity. These results can provide a basis for understanding the distribution pattern and influence mechanism of urbanization factors on plant diversity and serve as a reference for policymakers and planners of plant diversity conservation in Zhengzhou City.

Unveiling urbanization effects on trees outside forests along the urban-rural gradient in megacity Bengaluru

Rapid urbanization has caused significant changes along the urban-rural gradient, leading to a variety of landscapes that are mainly shaped by human activities. This dynamic interplay also influences the distribution and characteristics of trees outside forests (TOF). Understanding the pattern of these trees will support informed decision-making in urban planning, in conservation strategies, and altogether in sustainable land management practices in the urban context. In this study, we employed a deep learning-based object detection model and high resolution satellite imagery to identify 1.3 million trees with bounding boxes within a 250 ​km2 research transect spanning the urban-rural gradient of Bengaluru, a megacity in Southern India. Additionally, we developed an allometric equation to estimate diameter at breast height (DBH) from the tree crown diameter (CD) derived from the detected bounding boxes. Our study focused on analyzing variations in tree density and tree size along this gradient. The findings revealed distinct patterns: the urban domain displayed larger tree crown diameters (mean: 8.87 ​m) and DBH (mean: 43.78 ​cm) but having relatively low tree density (32 trees per hectare). Furthermore, with increasing distance from the city center, tree density increased, while the mean tree crown diameter and mean tree basal area decreased, showing clear differences of tree density and size between the urban and rural domains in Bengaluru. This study offers an efficient methodology that helps generating instructive insights into the dynamics of TOF along the urban-rural gradient. This may inform urban planning and management strategies for enhancing green infrastructure and biodiversity conservation in rapidly urbanizing cities like Bengaluru.

The impact of urban morphology on land surface temperature across urban-rural gradients in the Pearl River Delta, China

Optimizing urban morphology effectively mitigates urban heat island effects. However, previous research on urban morphology and land surface temperature (LST) has often concentrated on entire cities or specific local areas, neglecting the heterogeneity within urban regions. This study investigates the impact of two-dimensional (2D) and three-dimensional (3D) urban morphology on LST based on urban-rural gradients. Firstly, we calculated nine 2D and 3D indicators to comprehensively depict the urban morphology. Then, we employed a multi-iterative quantile method based on nighttime light data to delineate three city subclasses: urban core, suburb, and rural area (USR). Finally, we quantified the impact of these indicators on LST thorough correlation analysis and a random forest (RF) model. Results indicate that, overall and post-USR classification, the sum of building area (SBA) is the primary factor influencing LST, contributing up to 31.6% in suburb. The main 3D factors affecting LST differ across subclasses: in rural area, it is the sum of building surface (SBS, 12.9%); in suburb, it is the spatial congestion degree (SCD, 9.7%); and in urban cores, it is the mean building height (MBH, 12.0%). Notably, the influence of 3D indicators increases from 68.1% in rural area to 72.3% in urban core. In urban core, MBH and standard deviation of height (SDH) are negatively correlated with LST. Case studies in Tianhe District (Guangzhou) and Futian District (Shenzhen) confirmed these indicators do have a certain effect on reducing the temperature. This study provides valuable insights for improving the urban thermal environment and promoting sustainable urban development.

Community profiles in northeastern and central Pennsylvania characterized by distinct social, natural, food, and physical activity environments and their relation to type 2 diabetes.

Understanding geographic disparities in type 2 diabetes (T2D) requires approaches that account for communities' multidimensional nature. In an electronic health record nested case-control study, we identified 15,884 cases of new-onset T2D from 2008 to 2016, defined using encounter diagnoses, medication orders, and laboratory test results, and frequency-matched controls without T2D (79,400; 65,069 unique persons). We used finite mixture models to construct community profiles from social, natural, physical activity, and food environment measures. We estimated T2D odds ratios (OR) with 95% confidence intervals (CI) using logistic generalized estimating equation models, adjusted for sociodemographic variables. We examined associations with the profiles alone and combined them with either community type based on administrative boundaries or Census-based urban/rural status. We identified four profiles in 1069 communities in central and northeastern Pennsylvania along a rural-urban gradient: "sparse rural," "developed rural," "inner suburb," and "deprived urban core." Urban areas were densely populated with high physical activity resources and food outlets; however, they also had high socioeconomic deprivation and low greenness. Compared with "developed rural," T2D onset odds were higher in "deprived urban core" (1.24, CI = 1.16-1.33) and "inner suburb" (1.10, CI = 1.04-1.17). These associations with model-based community profiles were weaker than when combined with administrative boundaries or urban/rural status. Our findings suggest that in urban areas, diabetogenic features overwhelm T2D-protective features. The community profiles support the construct validity of administrative-community type and urban/rural status, previously reported, to evaluate geographic disparities in T2D onset in this geography.

Metal concentration in honeybees along an urbanization gradient in Central Mexico

Urbanization is rapidly increasing worldwide, leading to rising levels of pollution, one of the major drivers of environmental change; yet little is known about the relationship between urbanization intensity and pollution levels in pollinator taxa. Toxic metals are among the most common contaminants in urban environments, but few data exist on their presence in the flora and fauna of cities in Latin America, one of the world's most urbanized and biologically diverse regions. In this study, we used an urban-rural gradient approach to analyze the relationship between the concentrations of eleven metals present in adult honeybees (Apis mellifera) and the degree of urbanization within twelve landscapes in the metropolitan area of Pachuca, Hidalgo, which forms part of the megalopolis of Mexico City. Metal concentrations were compared with previously reported values contrasting honeybees from urban and rural areas after standardizing urbanization levels among published reports. The concentrations of Ag, Cr, Cu, and Zn in honeybees increased significantly with the degree of urbanization. Urbanization was not found to influence the levels of Al, Ba, Cd, Mn, and Sr in honeybees. The maximum concentrations of six metals in our urban sites (Al, Ba, Cd, Cu, Mn, and Sr) were higher than the maximum values reported for bees in other urban areas. The concentrations of two metals measured in our study (Cr and Zn) were within the range of values previously published for urban areas. Compared to other studies, we did not detect Pb in the body of honeybees. We conclude that the concentrations of Ag, Cr, Cu, and Zn present in honeybees are a quantitative reflection of the degree of urbanization in central Mexico. Our results highlight the need to monitor metal emission sources in this and other areas and investigate their effects on bees and other pollinator taxa.

The multiscale response of global cropland cropping intensity to urban expansion

CONTEXTUrban expansion(UE) and multiple cropping(MC) are key factors in anthropogenic impacts on global environmental change. However, the multi-scale response patterns of UE and MC have not yet been revealed, and how urbanization affects cropland intensification is still not deeply explored. OBJECTIVEThis study examines the spatial and temporal trends in global UE and MC and analyses the multi-scale response patterns of both. METHODSThe GEE (Google Earth Engine) platform was used to count global cropland cropping intensity (CCI) and impervious surface rasters on an image-by-image basis, while GIS was employed for spatial analyses, and the generalized additive model (GAM) was applied to inscribe variable response trajectories. RESULTS AND CONCLUSIONThe global multiple cropping index(MCI) increased significantly (by 4.1 %) over the period 2001–2019, with growth in double- and triple-cropped cropland dominating this change. Double cropping, as a widespread global farming strategy, has led to a shift towards the intensification of agriculture, with countries in the northern hemisphere contributing more. Global UE significantly expands to twice the baseline level at an average annual growth rate of 2. 42 × 104 km2 over the period 2001–2019, with the expansion of world-class urban agglomerations in China, the United States and Europe dominates this trend. The spatial clustering of MC and UE has continued to intensify, with high-intensity cropping strategies progressively clustering towards areas of significant UE, and this tendency has a clear decreasing urban-rural gradient effect. The global CCI grows significantly and non-linearly with UE, but an important inflection point in the growth trajectory has occurred under the influence of threshold effects. Developed countries tend to be more flexible in their cropping intensity strategies as they move forward with urbanization. There is a clear increasing effect of the urban-rural gradient in the degree of non-linearity in the response of urbanization and cropping intensity. SIGNIFICANCEThe results of the study contribute to the understanding of the complex spatial and temporal coupling mechanisms between UE and MC, and provide useful insights for the development of trade-offs between urbanization and maturity strategies.

Spatially Explicit Analysis of Landscape Structures, Urban Growth, and Economic Dynamics in Metropolitan Regions

Assuming that settlement morphologies and landscape structures are the result of economic transformations, the present study illustrates a statistical framework investigating metropolitan growth due to the inherent changes in landscape configurations vis à vis socio-demographic functions. Focusing on the evolution of their spatial drivers over time, metropolitan development was studied by adopting land parcels (or ‘patches’, as they are referred to in the ecological literature) as the elementary analysis unit—with the individual surface area and a specific shape indicator as the dependent variables and background socioeconomic attributes as predictors of landscape change over time. We specifically ran a Multiscale Geographically Weighted Regression (MGWR) testing the spatial dependence of the size and shape of landscape parcels on a vast ensemble of socioeconomic factors in a dense region (metropolitan Athens, Greece) with natural landscapes exposed to increasing human pressure. To investigate the spatial direction and intensity of the settlement expansion and landscape change, local regressions using the parcel area and fractal index (perimeter-to-area ratio) as the dependent variables and the elevation, distance from selected economic nodes, transport infrastructures, and natural amenities as the predictors were run separately for 1990 and 2018, representative of, respectively, a mono-centric configuration and a moderately polycentric organization of economic spaces. In a strictly mono-centric setting (1990), the parcel size showed a linear dependence on the distance from business districts, elevation, and wealth. Changes in the relationship between the parcel size and spatial (economic and non-economic) drivers may suggest a latent process of settlement de-concentration, and a possible shift toward polycentric development (2018), as documented in earlier studies. By integrating socioeconomic and ecological dimensions of landscape analysis and land evaluation, the empirical results of this study outline the increased complexity of dispersed landscape structures within dense metropolitan regions and along urban–rural gradients in Europe.

Dynamic Change Characteristics of Wetlands in Hefei and their Driving Factors Along the Urban–Rural Gradient

Wetlands, as vital components of urban ecological infrastructure, provide essential ecosystem services. However, they face increasing risks of degradation and loss due to their vulnerability, environmental changes, and human activities. Therefore, effective restoration efforts are urgently needed. This study adopts a novel approach by considering the urban–rural gradient and integrates land use data, ecological parameters, and anthropogenic factors in Hefei City. Through morphological spatial pattern analysis, principal component analysis, and affinity propagation, this study identifies and analyzes urban–rural gradients. Using the optimal parameter geographic detector, the drivers of wetland changes from 1990 to 2020 are quantitatively assessed across different urban–rural gradients in Hefei. The findings indicate the following. (1) A persistent reduction in wetland expanse throughout the study duration, diminishing from 1274.56 km2 in 1990 to 1119.37 km2 in 2020, constituting a decrement of 12.17%. (2) Based on geographic detector outcomes, disparate driving forces underpin wetland dynamics across urban–rural gradients, with urban locales predominantly influenced by organic carbon and the proportion of impervious surface factors. Meanwhile, in agricultural and semi-ecological villages, silt is the primary factor, while ecological villages are primarily modulated by both silt and gross domestic product factors. Additionally, synergistic interactions manifest heightened explanatory power. This study elucidates the mechanistic underpinnings of wetland dynamics along urban–rural gradients, providing pivotal insights for developing targeted wetland restoration and conservation policies pertinent to the urban–rural developmental trajectory in Hefei City. Concurrently, it offers relevant recommendations for the multifaceted stewardship and sustainable development of wetlands in Hefei City in the foreseeable future.

Evolution Process and Land Use/Land Cover Response of Urban–Rural Space in Wuhan under Polycentric Structure

Polycentric development facilitates urban–rural spatial reshaping and land use/land cover (LULC) protection. Previous studies have predominantly focused on urban areas, with spatial delineation methods biased towards the macro-level, lacking a holistic perspective that situates them within the urban–rural spatial framework. This study proposes a spatial delineation framework that is applicable to the polycentric structure, taking into account the social, economic, and natural characteristics of urbanization. It employs semivariance analysis and spatial continuous wavelet transform (SCWT) to analyze the effects of polycentric development on the urban–rural space of Wuhan from 2012 to 2021 and applies a land use transition matrix, landscape indices, and bivariate spatial autocorrelation to quantify the responses and differences of LULC within urban–rural space. The results indicate that 600m×600m is the best scale for exhibiting the multidimensional characterization of urbanization. The polycentric structure alleviates the compact development of the central city, and it drives rapid expansion at the urban–rural fringe, exacerbating the spatial heterogeneity in LULC change pattern, spatial configuration, and urbanization response within urban–rural spaces. The overall effects of urbanization on LULC are relatively weak along the urban–rural gradient, experiencing a transition from positive to negative and back to positive. This study employs a novel spatial delineation framework to depict the polycentric transformation of metropolitan areas and provides valuable insights for regional planning and ecological conservation in the urban–rural fringe.

From center to outlying areas: Navigating built-up land dynamics along urban-rural gradients in Global South megaregions

Understanding the dynamics of built-up land amidst the urban-rural transformation process is crucial for balancing the benefits of urbanization against the challenges of uncontrolled expansion. Yet, how built-up land develops across different types of human settlements, particularly within emerging Global South megaregions (GSMs), is not well documented. Employing an urban-rural gradient (URG) approach, we investigate built-up land dynamics across six representative emerging GSMs spanning 1985–2020, contextualizing our findings within urbanization theory and sustainable development discourse. Our analysis reveals that urban center growth and peri-urbanization drive a substantial proportion of built-up land expansion (36.47% and 27.39%, respectively), in contrast to the minimal increases observed in rural clusters and semi-dense areas (2.48% and 2.44%, respectively). The predominant expansion mode is sprawling growth, notably evident in peripheral areas, while densifying growth is mainly confined to urban centers and mostly uninhabited areas. Sprawling shrinkage is observed in dense and semi-dense urban areas, as well as rural clusters. These nuanced dynamics illustrate the varied ways in which regional territories engage with and are shaped by the urbanization process. Through the lens of the URG analysis, our study enhances understanding of spatial transformations in the GSMs, offering informative insights for fostering sustainable cities and human settlements.

Study on temperature regulation function of green spaces at community scale in high-density urban areas and planning design strategies

In recent years, the frequency of extreme high-temperature events has gradually increased. To better understand the impact of urban green space coverage's spatial pattern on land surface temperature (LST), this study selected three sample areas along the urban-rural gradient in Shanghai. Using LST inversion and resampling methods, LST data for different grid sizes were obtained for spring, summer, and winter in the 2010s, 2015s, and 2020 s. A boosting regression tree model was employed to determine the key indicators affecting LST and effective cooling thresholds. The impact of green quality, structure, and pattern at the community scale on LST was discussed, providing feasible suggestions for green space planning and design in different urban spaces. The study found significant differences in the spatial patterns of green areas and LST among the three sample regions. The quantity and integrity of green spaces in the Huangpu, Minhang, and Songjiang sample areas have progressively improved, with overall green coverages of 19 %, 38 %, and 43 %, respectively. As grid size increases, the relative influence of fractional vegetation coverage (FVC) on LST generally decreases, whereas the relative influence of green structure and patterns gradually increases. Taking the summer of the 2020 s as an example, the influence of FVC on the three study sample areas was 80.79, 83.36, and 87.18 at a 30 m grid size, which decreased to 48.87, 40.59, and 47.64 at a 120 m grid size. The green structure's impact rose from 13.09, 15.22, and 10.6–30.01, 51.82, and 38.5; the influence of green patterns increased from 6.12, 1.42, and 2.21–21.13, 7.6, and 13.86. Key indicators affecting LST include FVC (Fractional Vegetation Coverage), AREA (Green Patch Area), PD (Patch Density), COHESION (Patch Cohesion Index), and ED (Edge Density). High temperatures in summer are one of the ecological issues that need special attention in Shanghai's green space design. Setting the green space proportion to 35 % while avoiding fragmentation and low vegetation coverage can achieve effective cooling. This study's main advancement lies in utilizing machine learning algorithms to identify the principal green spatial pattern impact factors and key thresholds influencing LST at the community scale in Shanghai. The related results and proposed strategies provide a research framework and strong basis for special regulations in urban green space system planning concerning urban thermal environments. They offer references for urban renewal and new town planning to address climate change and urban high-temperature issues, such as clear requirements for optimal green space area at the community scale, community park spatial layout and quantity regulations, and urban park planning design suggestions. This study also highlights obstacles in the practical application of planning and design strategies, which can help avoid difficulties in implementing planning policies. It attempts to set goals for community-scale vegetation planning in China from a policy perspective and provides relevant recommendations.

Alteration in butterfly community structure along urban–rural gradient: with insights to conservation management

BackgroundEcosystem services rendered by the butterflies are important for the sustenance of community interaction. Butterfly species have also coevolved with the host and nectaring plants. In the adult condition, they mostly rely on nectar, while in the larval condition, they feed on the leaves of their host plants. Butterfly species are sensitive to changes in environmental parameters and are considered excellent indicators of ecosystem health. The study of species diversity and richness indices aids in better ecosystem management. The present study's goal was to determine butterfly diversity in the urban–rural gradient of Purulia district, West Bengal, India, a part of the Chota Nagpur Plateau. We aim to complement crucial information on butterfly conservation management in Purulia, West Bengal, India, and other similar geographical areas with the findings of this study.ResultsIt was found that out of 3809 sampled butterflies, the individual contribution of the family Nymphalidae was the highest (51.24%), followed by Lycaenidae (18.40%), Pieridae (17.32%), Papilionidae (9.74%), and Hesperiidae (3.12%). A total of 54 butterfly species were observed in the urban–rural gradient, out of which the urban region contained 49 species, the suburban region had 32 species, and the rural region had 30 species. Significant differences were observed in butterfly abundance for the sites, seasons, and families during the study period. PERMANOVA and ANOSIM for species abundance and species presence-absence data show that all three sites are significantly different. Results Both PCoA and NMDS revealed clear differences among sites (groups) in terms of species abundance and presence-absence data. According to the findings of this study, the urban region has the highest species richness, followed by the suburban and rural regions. We discovered that urban areas have the highest butterfly abundance, followed by suburban and rural areas. Numerous butterfly species prefer the bushes dominated by Lantanacamara in the urban region with the highest species richness. Aside from this invasive weed, the site also contains Tridaxprocumbens, Catharanthusroseus, Synedrellanodiflora, and Ocimumamericanum, which are well known for being butterfly nectaring plants. In the case of the suburban region, members of the Lycaenidae family contributed the highest percentage after Nymphalidae, which was dominated by Tridaxprocumbens and Sphagneticolatrilobata, which was preferred by the members of the Lycaenidae family observed during the survey, this site also contained Ixoracoccinea, Catharanthusroseus, and Lantanacamara. This site, in terms of nectaring plants, remains homogeneous in a rural region.ConclusionsOut of 3809 butterfly individuals, the family Nymphalidae contributed the most, followed by Lycaenidae, Pieridae, Papilionidae, and Hesperiidae. Both species richness and butterfly abundance were highest in urban regions, followed by sub-urban and rural regions. The current study has shown that this particular geographic location can sustain a variety of butterfly species. However, it is important to note that conservation planning is necessary not only for the butterfly species but also for the nectaring plant species that contribute to the diversity of these insects. The conservation of butterfly species can also lead to the achievement of ecosystem services they provide.

Urban scavenging: vertebrates display greater sensitivity to land-cover and garden vegetation cover than invertebrates

Scavenging removes carrion or littered food waste from the environment, promoting nutrient cycling, and reducing waste management costs. These ecosystem services are important in urban environments, where high human population densities result in increased littered food waste. It is unclear how the magnitude of scavenging across urban-rural gradients is influenced by agent, land-cover type, and patch size. We investigated scavenging provision by vertebrates and invertebrates across a gradient of urbanisation, based on impervious surface cover, in woodlands and gardens in Liverpool, UK. The percentage dry weight loss of bait after 48 h, deployed within vertebrate exclusion cages or exposed to vertebrates and invertebrates, was used to quantify scavenging provision. General linear mixed effects models were used to assess the relative contributions of vertebrates and invertebrates across an urban-rural gradient, variation in scavenging between woodlands and gardens, and the effects of semi-natural vegetation cover on scavenging in gardens. We consider patch size as a preliminary assessment of how fragmentation influences scavenging. Vertebrates contributed substantially more to scavenging than invertebrates across the urbanisation gradient. Vertebrate scavenging was greater in woodlands than gardens, while invertebrate scavenging remained consistent. Scavenging increased with patch size in gardens, but not woodlands. Vertebrate scavenging increased with patch size and garden semi-natural vegetation cover. Urban woodlands and gardens make important contributions to scavenging-mediated ecosystem services. There is a need to increase the cover of semi-natural vegetation in gardens to increase their contributions, and protect and expand woodlands, especially in areas with a high demand for scavenging-mediated ecosystem services.

Spatio-Temporal Analysis of Green Infrastructure along the Urban-Rural Gradient of the Cities of Bujumbura, Kinshasa and Lubumbashi

Spatio-Temporal Analysis of Green Infrastructure along the Urban-Rural Gradient of the Cities of Bujumbura, Kinshasa and Lubumbashi

Investigating Variations in Anthropogenic Heat Flux along Urban–Rural Gradients in 208 Cities in China during 2000–2016

Anthropogenic heat emissions, which are quantified as anthropogenic heat flux (AHF), have attracted significant attention due to their pronounced impacts on urban thermal environments and local climates. However, there remains a notable gap in research regarding the distinctions in the distribution of anthropogenic heat emissions (AHEs) along urban–rural gradients. To address this gap, the present study introduces a new concept—the anthropogenic urban heat island (ArUHI)—where the AHF within urban areas is higher than that in background areas. To quantitatively describe the magnitude and spatial extent of the ArUHI effect, two metrics—namely, ArUHI intensity (ArUHII) and ArUHI footprint (ArUHIFP)—are introduced. We conducted a comprehensive study across 208 cities in China to investigate the spatiotemporal patterns of AHF variations along urban–rural gradients during the period of 2000–2016. In addition, we explored how the complex interactions between land cover and building form components affect changes in the AHF along urban–rural gradients. Additionally, we analyzed how economic zones and city sizes alter the ArUHI intensity and ArUHI footprint. The results showed that 97% (201/208) of Chinese cities exhibited a significant ArUHI effect from 2000 to 2016. The modeled ArUHI intensity value exhibited a substantial increase of nearly fivefold, increasing from 5.55 ± 0.19 W/m2 to 26.84 ± 0.99 W/m2 over time. Regarding the spatial distribution of the ArUHI footprint, the analysis revealed that, for the majority of cities (86% or 179 out of 208), the ArUHI footprint ranged from 1.5 to 5.5 times that in urban areas. City sizes and economic zones yielded significant influences on the ArUHI intensity and ArUHI footprint values. Building forms were significantly positively correlated with AHF, with R2 values higher than 0.94. This study contributes to the understanding of ArUHI effects and their driving factors in China, providing valuable insights for urban climate studies and enhancing our understanding of surface urban heat island mechanisms.

Effects of Urbanization on Soil Quality in the Rural‒Urban Gradient of Bengaluru, India

Understanding the impact of urbanization on soil quality is crucial for sustainable land management practices. This study was conducted in Bengaluru, India, to estimate the soil quality index (SQI) under different rural‒urban gradient (RUG) zones. Twenty-four sampling sites were identified along the RUG, and soil samples were collected monthly over five months during the October to February of 2020-2021. The soil quality assessment involved selecting the minimum data set (MDS) via principal component analysis (PCA) and correlation, scoring soil indicators, and combining these scores to create the soil quality index (SQI). PCA was used to identify key soil properties, which included microbial biomass carbon (MBC), SOC, N, manganese (Mn), and urease for different RUG zones derived from the MDS. The rural zones had the highest SQI (0.57), followed by the peri-urban (0.47 and 0.48) and urban (0.45 and 0.47) zones. These findings emphasize the importance of sustainable land management practices to preserve and boost soil quality across diverse regions, particularly in the face of rapid urbanization and industrialization.