A Review of Urban Ecosystem Services Research in Southeast Asia

Relationship between the Duration of Urban Nature and a Lower Waist-Hip Ratio

Obesity is a prevalent health issue. Evidence suggests that the availability of urban nature may reduce the risks of obesity. However, several knowledge gaps remain. This study explores the relationships between the dose (distance, duration and frequency) of urban nature and demographic factors towards obesity risks among people in Thailand. A total of 111 participants in three urban and peri-urban nature locations answered a survey regarding their distance from green spaces, frequency of visits, and duration of their typical stay, as well as their socio-demographics, and waist-hip ratio (WHR). The results suggested that at least 1-2 h per typical visit to nature predicted low-risk WHR in women. Male participants are more likely to have a high-risk WHR. Increasing age predicted low-risk WHR. Spending more time in green spaces predicted lower odds of high-risk WHR, while distance did not predict the odds. This research is one of the first to study the relationship between time spent in nature and obesity, and one of the first nature and health studies conducted in Thailand. Given that Thailand is one of the countries most affected by obesity in Southeast Asia, this study is relevant and essential. Future research should explore the quality factors of the park with longer duration of stay.

Blue-Green Infrastructure for Flood and Water Quality Management in Southeast Asia: Evidence and Knowledge Gaps

In Southeast Asia, projections of rapid urban growth coupled with high water-related risks call for large investments in infrastructure-including in blue-green infrastructure (BGI) such as forests, parks, or vegetated engineered systems. However, most of the knowledge on BGI is produced in the global North, overlooking the diversity of urban contexts globally. Here, we review the literature on BGI for flood risk mitigation and water quality improvement in Southeast Asian cities to understand the scope of practical knowledge and identify research needs. We searched for evidence of local types of BGI in peer-reviewed and grey literature and assessed the performance of BGI based on hydrological, societal, and environmental metrics. The body of literature on BGI in Southeast Asia is small and dominated by wealthier countries but we found evidence of uptake among researchers and practitioners in most countries. Bioretention systems, constructed wetlands, and green cover received the most attention in research. Evidence from modelling and laboratory studies confirmed the potential for BGI to address flooding and water quality issues in the region. However, practical knowledge to mainstream the implementation of BGI remains limited, with insufficient primary hydrological data and information on societal and environmental impacts. In addition, the performance of BGI in combination with grey infrastructure, under climate change, or in informal settlements is poorly studied. Future research and practice should focus on producing and sharing empirical data, ultimately increasing the regional knowledge base to promote efficient BGI strategies.

Evaluating Neighborhood Green-Space Quality Using a Building Blue–Green Index (BBGI) in Nanjing, China

High-quality urban green space (UGS) is an integral part of a livable city. The scientific evaluation of UGS has great value for improving the quality and efficiency of green spaces. In this study, we integrated the water and walking networks into the existing green index model and proposed a new green index: the building blue–green index (BBGI). Using this method, we analyzed the quality of green spaces within 300 m of 2138 buildings located in 13 communities in the Mochou Lake subdistrict in Nanjing, China. The results revealed that the green-space quality of high-rise, low-density buildings was greater than that of low-rise, high-density buildings. In addition, buildings close to water had higher green-space quality, while impervious surfaces reduced green-space quality. Furthermore, the connectivity and orientation of the road network indicated that even if a community was close to large parks and water bodies, there would still be lower green-space quality. This study’s findings highlight the usefulness of evaluation methods for green-space quality that combine blue and green spaces. We also propose feasible measures for improving neighborhood green-space planning and land management.