Ecosystem service assessment of green roofs in Bangkok

Abstract

Green roofs are constructed ecosystems that can provide four main types of ecosystem services (regulating, provisioning, cultural, and supporting services). However, most green roof studies have focused on the regulating services and each ecosystem service type was usually evaluated separately. Moreover, there is a lack of assessment tool that can provide comparable outputs of total and different ecosystem services on green roofs, resulting in the difficulty to improve ecosystem service provision by green roofs. Therefore, this research aimed to (i) assess four main categories of ecosystem services provided by seven green roofs in Bangkok using direct measurement techniques and a novel rapid assessment checklist, (ii) investigate perception of people on green roofs and their ecosystem services using questionnaires and interviews with three groups of respondents; 259 university students, 90 workers, and five experts, and (iii) create a “Green roof ecosystem service” game for sharing the green roof knowledge with the public and concerned stakeholders. The results from the direct measurement showed that the selected green roofs in Bangkok could provide a combination of four main types of ecosystem services. The results from the rapid assessment checklist showed that the ecosystem service scores of seven sites ranged from 48 to 74 points from a maximum of 100. The green roof on Anantara Siam Bangkok hotel received the highest score of total ecosystem services of 74 points. Tradeoff and synergy among different green roof ecosystem services were observed. Different ecosystem services were influenced by green roof structure and design and management. Through the questionnaires and interviews, gas regulated was ranked as the first priority of ecosystem services ranked by the university students while the workers and experts cited climate regulation as the ecosystem service of the highest priority. Only 44% of the respondents knew the definition of the green roof. All of these results were used to create a series of green roof games which were used during gaming sessions with university students and experts. The results from pretest- posttest analysis from 18 gaming sessions, 449 participants, showed a significant improvement of green roof knowledge through playing the games. In summary, this research has contributed valuable knowledge of ecosystem services on green roofs by providing a convenient framework to assess ecosystem services and an innovative gaming and simulation for sharing the knowledge and raising awareness of the green roof ecosystem services.