Exploring habitat patch clusters based on network community detection to identify restored priority areas of ecological networks in urban areas

Ecological connectivity is the foundation of maintaining urban biodiversity and ecosystem health. Identifying and managing ecological (connectivity) networks can help maintain the stability of urban ecosystems. However, few studies have explored the cluster effect in the ecological network caused by the imbalance in connectivity strength between habitat patches, which is not conducive to the in-depth restoration of ecological networks. In the present study, a typical urban area, Shenzhen, was used as an example to analyze the important habitats in the city based on the focal species and to identify an ecological network. Habitat patch clusters in the ecological network were explored based on random walk network community detection. These are clusters of closely connected habitat lands. Finally, we analyzed existing urban policies for the protection of clusters and the points to be repaired in the network. The results showed that 50 ecological corridors connected 39 habitats in the study area, which further formed seven habitat patch clusters. Most of the clusters were well-protected by existing policies. Nineteen barrier points were identified between the clusters, and their restoration helped strengthen the connectivity between clusters. This study provides a reference for future urban ecological restoration.     

Emotional perceptions of people exposed to green and blue spaces in forest parks of cities at rapid urbanization regions of East China

Urbanization modifies the landscape with green and blue spaces (GBS), which further leads to a functional change along an urban-rural gradient. Emotional improvement is a critical service of GBS, which may be perceived and exposed through facial expressions by visitors. How people react, however, may vary at different locations of a city at varied phases of urbanization. In this study, happy and sad emotions were rated as scores from 7965 Sina-Weibo users who visited 77 GBS across 49 cities of East China in 2020. GBS were located in different regions of a city, either near downtown or in more rural-like regions. Compared to cities near the Hu Huanyong line, those along the eastern coast were built with parks that had smaller green spaces at lower elevations in locations near downtown. They also had larger blue spaces in parks at suburban areas of the same cities. People expressed more happiness in GBS in regions closer to remote rural regions, or in cities further from the eastern coast. Larger green spaces were associated with by the presentation more smiles in parks near downtown, while experiences in large blue spaces evoked positive emotions at suburban areas. Overall, GBS in population-dense regions of more developed cities can be perceived as an activation of exposing higher depression by visitors. More smiles can be exposed in GBS with a large green space near downtown, or with a large blue space at suburban regions of a city in East China.     

Accessibility to urban parks: Comparing GIS based measures in the city of Padova (Italy)

Accessibility to urban green spaces is essential for urban dwellers’ health and well-being. For planning purposes different accessibility measures and indicators have been used. Some are only based on availability, others consider distance from residences, yet others rely on gravity-based methods that consider both supply and demand. Different indicators often provide diverse and sometimes contradictory results and many issues remain in developing a comprehensive measure of accessibility, and representativity problems remain in matching indices with reality. In this study different accessibility measures have been developed and applied to the urban parks of the city of Padova, in northeastern Italy. Effectiveness and reliability of ten indicators derived from these measures, in identifying needs, inadequacies and disparities in park access have been tested at the urban unit scale. The study confirmed that multiple indicators need to be used to provide a useful planning tool for the provision of adequate and equal opportunities for open space access to the citizens. The study has also shown which indicators can be replaced by each other without losing important information.     

Urban agriculture and policy: Mitigating urban negative externalities

Agriculture and urban agglomerations can be combined in different perspectives, including building-integrated food production. Indeed, urban agriculture is less concerned with helping urban communities achieve food self-sufficiency and more concerned with strengthening urban inhabitants differently. "Different" signifies multifunctional forms of access to fresh and nutritious vegetables, food bill reduction, personal well-being, and user-friendly agriculture from socioeconomic perspectives. The study estimated willingness to pay and the value of socioeconomic benefits of urban agriculture practices. A choice experiment was performed in Colombo, Sri Lanka's most urbanized district in 2020. The data were estimated using the random parameter logit model. Positive and significant contributions to urban agriculture related to the utility of urban agriculture practitioners and non-practitioners were evident. The socioeconomic value of urban agriculture benefits generated is equivalent to USD 136,400 per community practices urban agriculture. Urban agriculture thus reveals its vitality as a tool for mitigating the negative impacts of urbanization. The research advocates Colombo municipality to actively encourage urban agriculture by including it in their planning policies.     

Constructing an Aims-Indicators-Methods framework for Green Space System Planning in China

Green Space System Planning (GSSP), taking all the green space within the city administrative area as a complete and comprehensive system, is a kind of official statutory planning that the Chinese government requires all the cities to draw up as a supplement for cities' Master Planning. It is the primary legal basis for green space protection and construction. Its temporal scale is 5 ∼ 20 years, and the planning area is gradually expanding from the urban area to the city area. With China's increasing emphasis on the ecological environment, green space development has been injected with more ecological functions. Simultaneously, the requirements for green space are added to the policy documents issued by several administrations about urban and rural planning. As a result, the qualitative and quantitative requirements for GSSP have become more complex than ever before. This article reviews and summarizes the laws, regulations, policy documents, and standards (national and industrial level) related to GSSP in the urban and rural planning field from the perspective of government requirements. The results show that the Chinese government's requirements for GSSP can be divided into three levels: mandatory, ecological, and promotional level. Furthermore, transforming the three-level requirements to their corresponding aims, this article constructed a hierarchical, multi-objective Aims-Indicators-Methods (AIM) framework of GSSP based on various aims and requirements. We hope that the AIM framework of GSSP can be more practical, which means regions can select an appropriate AIM framework according to their own environmental and economic conditions and simplify the preparation of GSSP.     

Greening residential quarters in China: What are the roles of urban form,socioeconomic factors,and biophysical context?

Residential greenspace has great intracity variations. Its driving factors have been widely investigated in Western countries (e.g., in Europe and North America), where residential areas are mostly privately owned, but few studies have examined the determinants of residential greenspace in China, where land is owned by the government. Taking the subtropical city of Changsha, China, as an example, this study mapped the percent green cover (PGC) in residential quarters with a fine-resolution satellite image. We also investigated its driving factors measured from multisource geospatial data. The results show that (1) the PGC in the residential quarters showed great spatial variation, with an average of 36.6% (0–85.7%) and a standard deviation of 18.3%. (2) Urban form, biophysical context, and socioeconomic factors together explained 49.18% of the variation in the PGC, and they independently explained 22.87%, 11.17%, and 2.31% of the variation, respectively. (3) Residential quarter size, PGC in the surrounding buffer zone, residential quarter age, housing value, and population density significantly and positively impact the PGC, while percent building cover, floor area ratio, and distance to city center had significant negative impacts. The strongest positive and negative impacts came from PGC in the surrounding buffer zone and percent building cover, respectively. Socioeconomic factors, the dominant driving factors in Western countries, show little impact on residential PGC. These findings expand our understanding of the intracity variation in greenspace coverage and the driving factors, which sheds light on the effective planning and management of urban greenspaces in China.     

Review on the multi-scale interactions of urban forests and atmospheric particles: Affecting factors are scale-dependent among tree,stand and region

Increasing studies worldwide have examined the impacts of urban forests on mitigating atmospheric particulate matter (PM) over the past decades. These scattered studies revealed the aerodynamics of atmospheric PM deposited on urban forests, as well as the various factors influencing the PM capture and removal by urban forests. However, these evidences are varying and even contradictory, and the affecting factors do not follow a universal pattern. In addition, these studies generally have been conducted in a specific scale such as leaf, stand and city without considering the multi-scale associations and incorporations. This literature review tried to address the associations of urban forest and PM removal across single tree, stand and regional scales, and summarized the confounding factors for PM capture and removal within each scale. Particle size and local meteorology have significant impacts across scales. For an individual tree, PM capture and removal capacity are largely determined by the leaf morphology and epidermal structures, but at the stand scale, the biophysical characteristics and configurational designs of urban forests are the essential factors. At the city and regional scale, the determinants are the fraction of forest coverage, as well as background pollution levels. The literature collation emphasizes the necessity of concerning the appropriate factors responding to the specific scale when quantifying and evaluating PM capture and removal by urban forests, and warrants a multi-scale research paradigm and inclusive modeling evaluation incorporating the confounding factors from multiple scales for PM capture and removal by urban forests.     

Park equity: Why subjective measures matter

Due to the various social and environmental benefits provided by urban parks and open spaces, ensuring that residents have equitable access to high-quality parks is paramount for planners and allied professionals. While research has identified inequities in park access based on race, ethnicity, and income, previous studies primarily focus on objective measures of access such as proximity to parks. Additionally, previous research typically includes single study regions that do not capture differences in distinct places. Relying on survey data from six metropolitan areas of the U.S., we address these gaps by investigating how subjective perceptions of parks vary by race/ethnicity and income (while controlling for other factors). Specifically, we employ linear mixed models to test for interaction effects between race/ethnicity and the six metro regions. We also compare subjective views of parks to ParkScore® rankings and metrics that represent park access. Overall, we found that perceived problems with park availability and quality were highest in the Baltimore area, as well as Los Angeles, Miami, and Boston; they were lowest is Phoenix and Minneapolis–St. Paul. Meanwhile, residents perceived significantly more improvements in park availability and quality in Miami and Minneapolis–St. Paul, followed by the other regions. Compared to objective ParkScore® measures, subjective perceptions of parks do not always follow the relative rankings of metrics for park access and quality. Additionally, Black and Hispanic residents perceived greater park problems than White residents, and Hispanic residents perceived more improvements than White residents. However, distinctions in public perceptions of parks by racial/ethnic groups and regions did not hold up in our mixed, multivariate models. Instead, our results highlight regionally distinct perceptions by race/ethnicity, suggesting that subjective views of park quality are context-dependent. In contrast, income is a more dominant driver of perceived improvements in local parks and open spaces. As a whole, this research underscores the need to consider both objective and subjective measures in particular geographic contexts to fully understand and plan for the equitable distribution of high-quality parks across diverse people and places.     

Advancing research on urban greenspace experiences and perceptions in disadvantaged communities: A social housing perspective

Empirical assessments of the experiences and perceptions of urban green space (UGS) in a social housing context are scant. Studying UGS perception in these contexts is important to understand how people experience and derive benefits from UGS in disadvantaged communities. This short communication provides interdisciplinary and methodological guidance on how to conduct empirical assessment of UGS experience and perception in social housing neighborhoods. For conducting these types of studies, we suggest researchers go beyond simply calculating UGS abundance around communities and consider assessing UGS experiences and perceptions. We suggest designing studies that account for the mixed nature of many social housing communities and that develop useful UGS perception measures that can be associated with wellbeing and community indicators. Finally, we also recommend: (1) designing studies at the local scale and developing strong relationsihps with the social housing communities before and while conducting these studies; (2) considering safety as a key component of UGS perception measures; (3) considering the association between UGS perception measures and wellbeing and community experience indicators to strengthen existing models of UGS benefit provision.     

Unmanned aerial systems for modelling air pollution removal by urban greenery

Urban greenery plays an important role in reducing air pollution, being one of the often-used, nature-based measures in sustainable and climate-resilient urban development. However, when modelling its effect on air pollution removal by dry deposition, coarse and time-limited data on vegetation properties are often included, disregarding the high spatial and temporal heterogeneity in urban forest canopies. Here, we present a detailed, physics-based approach for modelling particulate matter (PM₁₀) and tropospheric ozone (O₃) removal by urban greenery on a small scale that eliminates these constraints. Our procedure combines a dense network of low-cost optical and electrochemical air pollution sensors, and a remote sensing method for greenery structure monitoring derived from Unmanned aerial systems (UAS) imagery processed by the Structure from Motion (SfM) algorithm. This approach enabled the quantification of species- and individual-specific air pollution removal rates by woody plants throughout the growing season, exploring the high spatial and temporal variability of modelled removal rates within an urban forest. The total PM₁₀ and O₃ removal rates ranged from 7.6 g m^-2 (PM₁₀) and 12.6 g m^-2 (O₃) for mature trees of Acer pseudoplatanus to 0.1 g m^-2 and 0.1 g m^-2 for newly planted tree saplings of Salix daphnoides. The present study demonstrates that UAS-SfM can detect differences in structures among and within canopies and by involving these characteristics, they can shift the modelling of air pollution removal towards a level of individual woody plants and beyond, enabling more realistic and accurate quantification of air pollution removal. Moreover, this approach can be similarly applied when modelling other ecosystem services provided by urban greenery.