Can microbial inoculants boost soil food webs and vegetation development on newly constructed extensive green roofs?

Green roofs are a key to providing nature-based solutions in cities. However, most green roofs installed in the Northern hemisphere are shallow, stonecrop planted systems (“extensive” green roofs), which have been shown to support limited biodiversity and could be more effective at providing ecosystem services. One issue with this type of extensive green roof is that rootzones are almost sterile on construction, relying on natural colonisation to provide a soil food web. This is a slow process, meaning plant growth can also be slow. Our aim was to determine if a soil food web could be introduced when the green roof is built. We applied microbial inoculants (mycorrhizal fungi and bacteria (Bacillus spp.)) to a new green roof and monitored plant growth and the soil food web (bacteria, mycorrhizal fungi and microarthropods). Different inoculants altered the composition of microarthropod communities, potentially impacting later succession. In particular, bacterial inoculants increased microarthropod populations. This is one of the first studies to demonstrate that the addition of microbial inoculants impacts not only plant growth, but also faunal components of the soil food web, which could have implications for long-term resilience. Bacteria were effective at aiding mycorrhizal colonisation of plants roots, but this colonisation had no impact on the growth of our selected stonecrops, Sedum album, Petrosedum reflexum and Phedimus spurius. We suggest that if a beneficial mycorrhiza could be found to promote the growth of these specific species on green roofs, bacteria could be effective “helper” species to aid colonisation. This study enables green roof researchers and the industry to justify further exploration of the impact of microbial inoculants on green roofs.     

Can a problem-solving approach strengthen landscape ecology’s contribution to sustainable landscape planning?

The need to avert unacceptable and irreversible environmental change is the most urgent challenge facing society. Landscape ecology has the capacity to help address these challenges by providing spatially-explicit solutions to landscape sustainability problems. However, despite a large body of research, the real impact of landscape ecology on sustainable landscape management and planning is still limited. In this paper, we first outline a typology of landscape sustainability problems which serves to guide landscape ecologists in the problem-solving process. We then outline a formal problem-solving approach, whereby landscape ecologists can better bring about disciplinary integration, a consideration of multiple landscape functions over long time scales, and a focus on decision making. This framework explicitly considers multiple ecological objectives and socio-economic constraints, the spatial allocation of scarce resources to address these objectives, and the timing of the implementation of management actions. It aims to make explicit the problem-solving objectives, management options and the system understanding required to make sustainable landscape planning decisions. We propose that by adopting a more problem-solving approach, landscape ecologists can make a significant contribution towards realising sustainable future landscapes.     

A green infrastructure planning framework–guidance for priority,hubs and types

Green infrastructure (GI) has become an important tool to achieve sustainability and resilience in cities because of its various benefits, including stormwater management, urban heat island mitigation, air quality improvement, and carbon storage. Most existing studies have often focused on a single aspect, while few studies have incorporated the results of GI analysis into the planning process. To address this gap, we propose a planning framework to prepare the GI intervention solutions, aimed at identifying the priority actions, hubs to extract maximum multifunctionality, and preference types at the regional scale. We applied the planning framework to Wuhan city as a case study, and found an overall significant multifunctional potential. Two-thirds of the benefit pair (including spatial autocorrelation and bivariate spatial autocorrelation for benefits) relationships were found to be positive, and block areas approximately 15% of the total area were recommended as hubs to lay out the GI. Warnings should be received for evidence, revealing that industrial areas have higher requirements for GI that can alleviate the thermal environment and improve air quality. Strong positive correlations between various benefits were found in this area, especially based on a relatively large proportion of existing natural land. Further, we classified the types of GI preference by SOM (Self-organizing map neural network), and found that differentiated GI planning and strategy formulation are required by different types of regions. The planning framework provides intuitive guidance for GI intervention solution making, which can provide planners and government officials a deeper understanding of GI discourse based on clearly explained answers of important decision-making questions.     

Urban green spaces analysis for development planning in Colombo,Sri Lanka,utilizing THEOS satellite imagery – A remote sensing and GIS approach

Upon conclusion of the 30 years of civil conflict, Sri Lanka has entered into a new era of development. The beautification project of Colombo, Sri Lanka's commercial capital, can be considered as one of the most important projects among urban planning and restoration endeavours implemented throughout the island. In such urban development endeavour, green spaces planning play a crucial role in improving the environmental quality and standard of living of the residents. The objective of this study is to analyse the environmental quality in Colombo city based on green spaces and to provide appropriate recommendations to raise the environmental quality to international standards.In this study, green space areas were extracted from Thailand Earth Observation System (THEOS) satellite imagery using Normalized Difference Vegetation Index (NDVI). Extracted green space areas were further analysed quantitatively with air quality indicators and population density utilizing deductive indexing method at Grama Niladhari (GN) administrative division level to identify correlations of these factors. An environmental criticality map based on population density and percentage green spaces has been constructed to identify the areas with high criticality. The study revealed that 24% of the entire Colombo Municipal Council (CMC) area consists of green spaces. This study also revealed that 34 GN divisions out of 55 lack the minimum per capita green space recommended by World Health Organization for healthy living. Recommendations are presented regarding regions where new green spaces should be established to enhance the environmental standard of living up to international standards.     

Can we integrate ecological approaches to improve plant selection for green infrastructure?

Modern cities are dominated by impervious surfaces that absorb, store and release heat in summer, create large volumes of runoff and provide limited biodiversity habitat and poor air quality can also be a health issue. Future climate change, including more frequent and extreme weather events will likely exacerbate these issues. Green infrastructure such as parks, gardens, street trees and engineered technologies such as green roofs and walls, facades and raingardens can help mitigate these problems. This relies on selecting plants that can persist in urban environments and improve stormwater retention, cooling, biodiversity and air pollution. However, plant selection for green infrastructure is challenging where there is limited information on species tolerance to heat and water variability or how these species can deliver multiple benefits. Therefore, we draw on research to illustrate how plant performance for green infrastructure can be inferred from plant attributes (i.e., traits) or from analysis of their natural distribution. We present a new framework for plant selection for green infrastructure and use a case study to demonstrate how this approach has been used to select trees and shrubs for Australian cities. We have shown through the case study and examples, how plant traits and species’ natural distribution can be used to overcome the lack of information on tolerance to both individual and multiple stressors; and how species contribute to the provision of benefits such as stormwater retention, cooling, biodiversity and air pollution mitigation. We also discuss how planting design and species diversity can contribute to achieving multiple benefits to make the most of contested space in dense cities, and to also reduce the risk of failure in urban greening.     

Synergy of urban green space planning and ecosystem services provision: A longitudinal exploration of China’s development

Ecosystem services (ES) concepts and approaches have become more appealing to practice, such as municipal/urban planning, environmental policies and governance to address sustainable development. Inclusion of this concept in the planning or policy discourses is the first step for further implementation on the ground. Using China’s capital, Beijing, as the case study, this article analyzes how ES (or similar concepts) have permeated China’s urban development history since 1949 when the New China was established and how this has to be with China’s urban green space development. The results show: (1) There were no explicit references to “ecosystem services” per se, but overlapping concepts such as “functions”, “values” and “benefits” can be found in planning documents and, importantly, the lack of the concept per se has not affected the detailed services that emerged in all plans. (2) Among the three ES sections, only cultural services run from the beginning to end although the included services kept changing. Other sections show considerable variation and less continuity – the focal services of each stage changed over time. (3) Through the ES lens, some general patterns regarding China’s urban development can be found such as regulation services gradually become valued for their own sake. The patterns found in Chinese planning documents are then compared with some western regions. This study reveals limitations of the past and opportunities for the future to inform urban development decision-making. Adaptation of old and incorporating new ES concepts can improve the quality of plans and foster cities’ ability to learn from past patterns for future sustainability.     

‘Just green enough’ in urban renewal: A multifunctional and pragmatic approach in realizing multiscale urban green space optimization in built-up residential areas

Urban green spaces (UGSs) play an essential role in sustainable urban development and are closely related to public health and human well-being. Previous studies seldom consider the relationships between spatial patterns and equity for the heterogeneity of built-up residential types in the city, not to mention how to place the pragmatic design strategies to explore green injustice for vulnerable neighborhoods. To address this gap, our study adopts a cascade of three methodological stages: 1) applying an urban morphological spatial pattern analysis (MSPA) to compare urban UGS patterns and the UGS-adapted Gini coefficient to measure the spatial equity of UGS distributions in three local built-up areas, 2) employing the minimum cumulative resistance (MCR) model to determine the location of the newly added UGSs and adopting the ‘just green enough’ strategy into the redistribution of UGSs for the marginal neighborhood and at the same time to avoid inequality associated with green gentrification, and 3) exploring an integrated design and implementation method for the newly added UGSs that can accommodate both normal conditions and the possibility of future pandemics. The results indicate that there is a strong correlation between socioeconomic status and the distributional justice of UGSs among built-up types, while disadvantaged people living in the densest residential neighborhoods have lower UGS provisions. This paper demonstrates a multifunctional and pragmatic approach for realizing multiscale UGS optimization by exploring it at the subdivision and neighborhood scales. This implication can also help guide decision-makers and planners to understand the complex interplay between social vulnerabilities, gentrification, and urban greening, thus formulating effective policies and hands-on strategies to address green injustice that are not only crucial for this study region but also of great significance for developing countries in the Global South.     

Can you really see ‘green’? Assessing physical and self-reported measurements of urban greenery

Urban vegetation provides a wide array of services; yet, there is still a knowledge gap regarding the mechanistic processes behind urban vegetation–human well-being relationships. Two main approaches have been used to assess urban greenery associated with human well-being: physical and self-reported. We here assessed the associations between physical (green view index–GVI, green cover–GC) and self-reported measures (perceived visible greenery–PVG) of the streetscape greenery of two southeastern Mexican settlements (Xalapa, Coatepec). Our results show that both sites have considerable GC (Xalapa = 37.2%, Coatepec = 47.4%). We found a clear association between GVI and GC in Xalapa, but none in Coatepec. The latter was due to an important proportion of the vegetation of Coatepec being mainly constrained at block interiors, obstructed by walls. Regarding the self-reported measure, our results show an important discrepancy in relation to one of the physical measures (GVI), assessed through PVG/GVI ratios. In general, respondents tended to overestimate greenery, with greater overestimations related to GVI values <10%. Among the assessed respondent traits (gender, education level, live and/or work in neighborhood, time living and/or working in neighborhood), we found none to explain variations of PVG/GVI ratios in Coatepec, but respondent age did relate, non-linearly, with PVG/GVI ratios in Xalapa. In a nutshell, our findings indicate that the assessed physical and self-reported measures capture different aspects of urban greenery that differ in their potential uses, with GVI representing a helpful tool to quantify visible greenery at eye-level; GC being a highly informative physical measure to assess the amount of public and/or private urban greenery; and PVG as a quick and inexpensive measure of people’s perception of visible urban greenery. Depending on the monitoring, managing, and/or planning goals, the use of the three assessed measures can provide an integral evaluation of urban greenery.     

Is greening the building envelope economically sustainable? An analysis to evaluate the advantages of economy of scope of vertical greening systems and green roofs

A wide replication of green envelopes can be a good opportunity to improve urban environment conditions, as demonstrated by several studies. Greening systems increase also building envelope performances; however their economic sustainability has not been fully investigated. This study evaluates the economic sustainability of two combined greening systems installed on an office building: a vertical greening system and a green roof, and it evaluates the advantages of economy of scope. The Cost-Benefit Analysis on two different combinations of vertical greening and green roofs considers personal benefits and costs over their life cycle. The results demonstrate the advantages of economy of scope, due to the additional benefits coming from the combination of two different systems. The results show that the tax incentives and the combination of green systems can make the installation and the maintenance costs economically sustainable during the life span of a greening system; this could lead to a wider diffusion of greening systems with higher environmental and aesthetic performances.     

How is quality of urban green spaces associated with physical activity and health?

This study investigates the associations between quality of urban green spaces (UGS), self-reported physical activity (PA), and health indicators in Aydın, Turkey. Data was collected through a survey with 420 participants. The associations between quality of UGS, self-reported frequency and duration of PA, and stress, mental health, and physical health were examined with multivariate linear regression while controlling for confounding factors. Results showed that nearest distance to UGS and quality of UGS (i.e. maintenance and cleanliness) were associated with increased frequency of PA. Higher frequency of PA was related to less stress and better mental health and longer duration of PA was associated with better physical health. In addition, large and open/visible UGS were associated with better physical health. The findings also showed that stress mediates the relationship between PA and mental health. Results suggest that providing large, visible as well as clean and well-maintained UGS close to people's homes may be an effective strategy to improve PA and people's health.     

Can pruning help maintain vitality of ash trees affected by ash dieback in urban landscapes?

Hymenoscyphus fraxineus causes a destructive invasive tree disease known as ash dieback threatening the survival of common ash not only in the forests, but also in urban and landscape settings. Pruning is a potential management practice that could help maintain tree vitality and aesthetics in parks, gardens, alleys and recreation areas, as well as maintaining veteran trees having high heritage or cultural value, or trees with high genetic importance (e.g. located in clonal seed orchards). In this study we investigated the maximum distance proximal to the lesion margin at which H. fraxineus can be detected on individual branches infected by the fungus in order to provide recommendations for pruning. Pruning of branches was carried out on 38 trees in southern Sweden. Tissue samples including bark and wood were collected from the margin of the lesion and at 5 cm intervals proximal to the lesion. Molecular analysis revealed presence of H. fraxineus in 91.3% of the investigated lesions. The proportion of lesions at which H. fraxineus could be detected declined with increasing distance from the lesion margin, with a significant reduction in the number of positive samples at 10 cm proximal to the margin. At 30 cm from the lesion edge the pathogen was never detected. Our results suggest that routine pruning may help maintain the vitality of younger trees. Pruning branches at least 35 cm from visible, active lesions in the bark should exclude the fungus and therefore reduce the probability of stem infection by H. fraxineus, however this cultural control tactic may only be economically feasible for high value amenity trees.     

Can restoring vacant lots help reduce crime? An examination of a program in Baltimore,MD

Urban green spaces have previously been linked to reduction in crime and improvements in neighborhood environments. This study considered if the Care-A-Lot (CAL) program in Baltimore City, which incentivizes local community groups to maintain and green vacant lots, reduces violent and property crime. Compared to a 2016–2017 baseline, city block groups with CAL programs saw a significantly larger decrease in crime compared to matched block groups with no CAL programs both in 2018 and 2019. These results were found to be robust through a series of sensitivity analyses and add to the literature stressing the positive social impact of green spaces.     

Can urban green space cure homesickness? Case study on China poverty alleviation migrants in Anshun,Guizhou

With the implement of China's ex-situ poverty alleviation resettlement (ESPAR) policy, nearly 10 million rural population have relocated with a better living condition in a short period of time, most of which have migrated to urban areas. The living environment and lifestyle of the poverty alleviation migrants (PAMs) have undergone dramatic changes, the resulting mental health problems may seriously affect their social integration and well-being. In particular, homesickness is a prevalent mental problem among the PAMs that demand prompt attention. Research indicates that longing for natural environment is one of the major causes of homesickness among rural out-migrants. As the main natural environment in cities, urban green space has been proven by numerous studies to have a positive effect on residents' mental health in various aspects, including reducing anxiety, relieving fatigue, and fostering perseverance. However, few studies have focused on the influence of urban green space on the mental health of the PAMs, especially on alleviating their homesickness syndrome. Using the data collected from interviews and questionnaire survey in the PAMs’ resettlement sites in Anshun, Guizhou, which has undertaken a heavy poverty alleviation task, this study examined the relationship between the physical activity, environment, function of urban green space, and the severity of PAMs’ homesickness, meanwhile paying attention to the impacts caused by different socio-demographic characteristics. The results show that urban green space is strongly associated with alleviating PAMs’ homesickness, and that all three factors play a positive role. Neighborhood green space is used the most, but suburban green space seems to provide better alleviation of homesickness. This study sheds lights on the critical role of urban green space for promoting PAMs' mental health, and aims to provide scientific reference to the planning and improvement for future migrant resettlements and urban green space.     

Is love for green in our genes? A critical analysis of evolutionary assumptions in restorative environments research

Within the field of restorative environments research, it is commonly assumed that restorative responses, triggered by exposure to natural elements and settings, are ultimately adaptive traits originating from our species’ long evolutionary history in natural environments. The aim of this article is to critically investigate the viability of this evolutionary view on restoration. In doing so, we specifically focus on Stress Recovery Theory (SRT), as this theoretical framework has most extensively elaborated on the supposed evolutionary origins of restoration. A detailed analysis of SRT's psycho-evolutionary framework shows that neither current empirical evidence nor conceptual arguments provide any strong support for the hypothesis of restorative responses to nature as an ancient evolved adaptive trait. Based on this conclusion we put forward an alternative model for restorative responses to nature based on processing fluency, which prima facie circumvents some of the pitfalls associated with evolutionary accounts for restoration. The Discussion section reflects on the implications of our critical discussion for the theory and practice of urban forestry and urban greening.     

Can waterbirds with different movement,dietary and foraging functional traits occupy similar ecological niches?

Context

Competitive interactions potentially play an important role in structuring bird communities. It is unclear how differences in functional traits influence the niche dimensions of highly mobile waterbird species, particularly when they co-exist in spatiotemporally heterogeneous communities.

Objectives

We investigated the inter-relationships between waterbird trait groupings (movement, dietary and foraging habitat) and environmental variable groupings (rainfall, land cover, vegetation structure and water quality). Specifically, we tested whether the scale of environmental variables filtered movement traits and whether these traits operated in conjunction with dietary and foraging habitat traits to form distinct ecological niches in waterbirds.

Methods

We conducted waterbird and environmental variable surveys in 60 sites, sampled seven times each at bimonthly intervals, in KwaZulu-Natal, South Africa. Trait-environment relationships were tested using a combination of RLQ and fourth-corner analyses.

Results

Several significant trait-environment relationships emerged in bivariate correlations and multivariate ordination space. Movement traits correlated with the scale of environmental variables; migrant and nomadic species responded to broad scale environmental variables. Vegetation structure and land cover were particularly important in explaining the abundance of species foraging in emergent vegetation. Three groups emerged along a gradient in multivariate ordination space providing evidence for ecological niche separation of waterbirds with different movement traits.

Conclusions

Our findings suggest that the scale of landscape resources can act as a filter of movement traits, and that in conjunction with dietary and foraging traits, waterbirds with different movement traits occupy distinct ecological niches.

     

How perceived sensory dimensions of urban green spaces are associated with adults’ perceived restoration,stress, and mental health?

This study investigates associations between perceived sensory dimensions (PSDs) of urban green spaces (UGSs) and adults’ perceived restoration, stress, and mental health. Data were collected through surveys with 426 adults in 2019 in seven different UGSs in Aydın, Turkey. The PSDs of UGSs (nature, serene, space, rich in species, social, prospect, culture, and refuge) were evaluated and rated by two professional landscape architects. The perceived restorativeness (being away, fascination, coherence, and compatibility) was measured with the Perceived Restorativeness Scale, and health indicators (stress, mental health, mental health diagnosis, mental health treatment, general health, and quality of life) were measured with self-reported questions. Multivariate multiple regression analyses were conducted to examine associations controlling for confounding factors. Four of the eight PSDs were analyzed due to multicollinearity issues in the study. Regression analyses showed that ‘nature’ was positively associated with perceived restorativeness, stress, and mental health, while ‘refuge’ was only positively associated with perceived restorativeness. On the other hand, ‘serene’ was negatively associated with perceived restorativeness. Whereas ‘rich in species’ was found to be negatively associated with perceived restorativeness and positively associated with mental health diagnosis. In addition, findings showed that frequency of and duration of UGSs visit were negatively associated with perceived restorativeness. The findings suggest that providing characteristics of ‘nature’ and ‘refuge’ in UGSs may provide restorative effects and mental benefits to adults. However, unexpected results suggest that further research is needed before using these characteristics as a tool by landscape architects and city planners.     

How did the COVID-19 pandemic impact urban green spaces? A multi-scale assessment of Jeddah megacity (Saudi Arabia)

The outbreak of the COVID-19 pandemic emerged as a global public health threat. In this crisis period, urban parks provided multiple ecosystem services and direct/indirect benefits to mental and physical health. However, the use patterns, attitudes, and perceptions of urban park visitors remained unexplored in Saudi cities. This study aimed to find out the use patterns, attitudes, and perceptions of people regarding urban parks during the COVID-19 pandemic, and the findings were compared with non-pandemic periods. Two urban parks (Al Masarah Garden and Al Jamaa Garden) in Jeddah megacity (Saudi Arabia) were assessed, and 215 respondents were surveyed to fulfil the objectives of the study. The study applied a questionnaire survey and field observations to understand the impact of the COVID-19 pandemic on the use patterns, attitudes, and perceptions of urban park visitors. Non-parametric tests (Kruskal–Wallis and Mann–Whitney tests) were performed to find out the impact of sociodemographic factors (such as age, gender, and education). From the results, it was found that the COVID-19 pandemic had a substantial impact on the use, attitudes, and perceptions of urban parks in comparison with non-pandemic periods. The number of park visitors decreased during the COVID-19 pandemic, but urban parks were crucial to people’s mental and physical well-being. The findings of this study may help to understand the importance of urban parks as green spaces and to implement measures to enhance the quality and quantity of urban green spaces in Saudi cities.