The impact of gardening on mental resilience in times of stress: A case study during the COVID-19 pandemic in Singapore.

To curb the spread of Covid-19, Singapore, like other cities, had to impose movement restriction and social distancing measures that may affect the well-being of its residents. In this paper, we assessed the potential benefits of gardening on the mental well-being of Singapore residents, based on the concept of mental resilience. We hypothesized that gardening activities promote mental resilience. A survey was administered on 8,786 participants of a "Gardening with Edibles" programme, measuring their mental resilience status, engagement in gardening activities and socio-demographic information. The mental resilience scores of participants who engaged in weekly gardening were compared with the scores derived from another survey conducted during the pandemic on an online community comprising demographically representative respondents with an interest on Covid-19 related community care. The results showed that the mental resilience of those who gardened was statistically significantly higher than the online community. Within the gardening group, those with less than one hour of weekly gardening time had significantly lower scores in their total mental resilience, and five out of seven resilience factors, "emotional regulation", "relationship", "confidence", "positive thinking" and "spirituality", compared to those with more weekly gardening time, showing that the efficacy of the mediating effects may peak at a weekly gardening time of between one to four hours. Home gardening may be an effective way for people living in densely populated cities to interact with nature and build mental resilience during the pandemic.

Bioretention systems for stormwater management: Recent advances and future prospects.

Bioretention is a popular stormwater management strategy that is often utilized in urban environments to combat water quality and hydrological impacts of stormwater. This goal is achieved by selective designing of a system, which consists of suitable vegetation at the top planted on an engineered media with drainage system and possible underdrain at the bottom. Bibliometric analysis on bioretention studies indicates that most of the original research contributions are derived from a few countries and selected research groups. Hence, most of the bioretention systems installed in diverse geographical locations are based on guidelines from climatically different countries, which often lead to operational failures. The current review critically analyzes recent research findings from the bioretention literature, provides the authors' perspectives on the current state of knowledge, highlights the key knowledge gaps in bioretention research, and points out future research directions to make further advances in the field. Specifically, the role and desired features of bioretention components, the importance of fundamental investigations in laboratory, field-based studies and modeling efforts, the real-time process control of bioretention cells, bioretention system design considerations, and life cycle assessment of full-scale bioretention systems are discussed. The importance of local conditions in guiding bioretention designs in difference climates is emphasized. At the end of the review, current technical challenges are identified and recommendations to overcome them are provided. This comprehensive review not only offers fundamental insights into bioretention technology, but also provides novel ideas to combat issues related to urban runoff and achieve sustainable stormwater management.

A conceptual framework to untangle the concept of urban ecosystem services.

Urban ecosystem service (UES) is becoming an influential concept to guide the planning, design, and management of urban landscapes towards urban sustainability. However, its use is hindered by definitional ambiguity, and the conceptual bases underpinning its application remain weak. This is exemplified by two different but equally valid interpretations of UES: "urban ecosystem services", referring to ecosystem services from analogs of natural and semi-natural ecosystems within urban boundaries, and "urban ecosystem services", a much broader term that includes the former group as well as urban services in a city. While we recognize that a single definition of UES is not possible nor necessary as its application is context-dependent, it is nevertheless useful to clarify the relationships between these interpretations to promote consistent use, and importantly, explore how a broader interpretation of UES might advance its applications in areas that have been neglected. We developed a conceptual framework that links UES to natural and human-derived capital to explain the relationships between the dual meanings of UES and proposed three normative propositions to guide its application: (1) integrate holistically multiple components of natural capital to provide UES, (2) reduce dependence on non-renewable abiotic resources and human-derived capital, and (3) enhance UES through technology. The framework we developed helps to resolve the current ambiguity in the meanings of UES, highlights the need to recognise neglected aspects of natural capital important for UES, and can be used to clarify relationships with related concepts conveying dependence of human well-being on nature.

The influence of the COVID-19 pandemic on the demand for different shades of green.

COVID-19 has heightened the dependence of urban dwellers on cultural ecosystem services provided by urban green spaces (UGS), specifically in regard to the provision of recreational opportunities, and psychological and physical health benefits arising from their use.As different types and levels of cultural ecosystem services are provided by different types of UGS, people may seek out different UGS to satisfy personal needs over various phases of COVID-19 mobility restrictions imposed by cities. We report on a study that took advantage of the different phases of COVID-19 mobility restrictions to assess the demand for and perception of different types of UGS in Singapore.The study utilised four datasets to compare demand for and visitorship patterns of UGS before the pandemic (Pre-Circuit Breaker), the duration of the strictest mobility restrictions (Circuit Breaker), and after the measures were relaxed (Post-Circuit Breaker). We used Google Search trends as a proxy for UGS demand, Google mobility data for an overview of population visitorship trends, visitor counts for granular insights on actual visitorship trends, and qualitative data on perception of parks by park visitors after restrictions eased. Parks were categorised as manicured and less manicured UGS for analysis.Search interest for UGS overall fell by more than 50% from during Circuit Breaker but the post-Circuit Breaker levels exceeded pre-Circuit Breaker, with a 70.9% increase for less manicured UGS compared to 20.8% for manicured UGS. This corroborated with Google mobility and visitor counts, which showed a steep decrease in park use followed by a rapid increase in the same periods, and with increased visitorship in the less manicured UGS. The perception study also showed that more than 50% of respondents reported visiting parks that they have never visited before, and there was a greater appreciation and use of UGS after the pandemic and preference for less manicured and more naturalistic landscapes.The pandemic has heightened the demand for cultural ecosystem services provided by UGS. Our study showed that this demand is not uniform across different types of UGS, with an increase visitorship and preference for less manicured green spaces. Read the free Plain Language Summary for this article on the Journal blog.

Integrating solutions to adapt cities for climate change.

Record climate extremes are reducing urban liveability, compounding inequality, and threatening infrastructure. Adaptation measures that integrate technological, nature-based, and social solutions can provide multiple co-benefits to address complex socioecological issues in cities while increasing resilience to potential impacts. However, there remain many challenges to developing and implementing integrated solutions. In this Viewpoint, we consider the value of integrating across the three solution sets, the challenges and potential enablers for integrating solution sets, and present examples of challenges and adopted solutions in three cities with different urban contexts and climates (Freiburg, Germany; Durban, South Africa; and Singapore). We conclude with a discussion of research directions and provide a road map to identify the actions that enable successful implementation of integrated climate solutions. We highlight the need for more systematic research that targets enabling environments for integration; achieving integrated solutions in different contexts to avoid maladaptation; simultaneously improving liveability, sustainability, and equality; and replicating via transfer and scale-up of local solutions. Cities in systematically disadvantaged countries (sometimes referred to as the Global South) are central to future urban development and must be prioritised. Helping decision makers and communities understand the potential opportunities associated with integrated solutions for climate change will encourage urgent and deliberate strides towards adapting cities to the dynamic climate reality.

Using social media user attributes to understand human-environment interactions at urban parks.

Urban parks and green spaces are among the few places where city dwellers can have regular contact with nature and engage in outdoor recreation. Social media data provide opportunities to understand such human-environment interactions. While studies have demonstrated that geo-located photographs are useful indicators of recreation across different spaces, recreation behaviour also varies between different groups of people. Our study used social media to assess behavioural patterns across different groups of park users in tropical Singapore. 4,674 users were grouped based on the location and content of their photographs on the Flickr platform. We analysed how these groups varied spatially in the parks they visited, as well as in their photography behaviour. Over 250,000 photographs were analysed, including those uploaded and favourited by users, and all photographs taken at city parks. There were significant differences in the number and types of park photographs between tourists and locals, and between user-group axes formed from users' photograph content. Spatial mapping of different user groups showed distinct patterns in the parks they were attracted to. Future work should consider such variability both within and between data sources, to provide a more context-dependent understanding of human-environment interactions and preferences for outdoor recreation.

Transpiration and cooling potential of tropical urban trees from different native habitats.

Urban trees are widely promoted as a solution to cool the urban environment because of shading and evaporative cooling provided by tree canopies. The extent to which the cooling benefits are realized is dependent not just on the genetically determined traits of trees, but also by their interactions with the atmospheric and edaphic conditions in urban areas, for which there is currently a paucity of information. We conducted a field experiment to compare whole-tree transpiration (Et) of tropical urban species from seasonally dry forest (SDF) (Tabebuia rosea, Lagerstroemia speciosa, Delonix regia, Caesalpinia ferrea, Dalbergia sissoo, Samanea saman) and aseasonal evergreen forest (AEF) (Peltophorum pterocarpum, Sindora wallichii). We examined the dependence of Et on atmospheric conditions (solar radiation (Rn) and vapor pressure deficit (VPD)), as well as on soil moisture level (θv). Daily Et differences between species were large but not statistically significant overall: 2000-3200 g m-2 (leaf area) under sunny conditions and 980-2000 g m-2 under cloudy conditions. The led to a daily latent heat flux (LE) of 770 W m-2 between the species with the highest (2136 W m-2) and lowest (1369 W m-2) daily Et. SDF species had higher daily Et than AEF species, but the difference was only significant under cloudy condition. Rn had a slightly stronger role in influencing transpiration compared to VPD, and species responses to drought stress differed marginally between the two groups. We assessed if two plant functional traits, wood density (ρw) and leaf stomatal conductance (gs), could be used to predict Et. Only gs was shown to be moderately correlated with Et, but more studies are needed to assess this given the limited number of species used in the study.

Associations between Urban Green Spaces and Health are Dependent on the Analytical Scale and How Urban Green Spaces are Measured.

Although the benefits from exposure to urban green spaces (UGS) are increasingly reported, there are important knowledge gaps in the nature of UGS-health relationships. One such unknown area is the dependence of UGS-health associations on the types of UGS studied, the way they are quantified, and the spatial scale used in the analysis. These knowledge gaps have important ramifications on our ability to develop generalizations to promote implementation and facilitate comparative studies across different socio-cultural and socio-economic contexts. We conducted a study in Singapore to examine the dependence of UGS-health associations on the metrics for quantifying UGS (vegetation cover, canopy cover and park area) in different types of buffer area (circular, nested and network) at different spatial scales. A population-based household survey (n = 1000) was used to collect information on self-reported health and perception and usage pattern of UGS. The results showed that although all three UGS metrics were positively related to mental health at certain scales, overall, canopy cover showed the strongest associations with mental health at most scales. There also appears to be minimum and maximum threshold levels of spatial scale at which UGS and health have significant associations, with the strongest associations consistently shown between 400 m to 1600 m in different buffer types. We discuss the significance of these results for UGS-health studies and applications in UGS planning for improved health of urban dwellers.