ASSESSMENT OF ECOSYSTEM SERVICES AND BENEFITS OF ROOFTOP GARDENING FOR ECO-FRIENDLY CITY DEVELOPMENT USING GEOSPATIAL TECHNOLOGY

Abstract

Humanity is increasingly urban, but continues to depend on nature for its survival. Cities are dependent on the ecosystems beyond the city limits, but also benefit from internal urban ecosystems. The aim of this study is to identify the ecosystem services generated by ecosystems within the Rooftop Gardens and to examine the biotic and abiotic components that contribute to overall ecosystem services. The experimental survey was conducted from June, 2014 to March, 2015. A questionnaire survey was conducted by face to face interviewing of forty respondent garden owners among four different Thana (Mohammadpur, Adabor, Dhanmondi and Kalabagan) within Dhaka city. Data were collected both qualitatively and wherever possible quantitatively. Thermal performance of Roof gardening was measured using Thermo-hygrograph at the warmest week of the year. The experimental analysis of thermal performance resulted that average roof air temperature is reduced by 5.2°C with roof garden during sunshine hours while average room temperature is reduced by 1.7°C with roof garden compared to bare roof. ‘Ecosystem services’ found in the research were provisioning services (Fruits and Vegetable production), supporting services (plant species diversity conservation and economic support), regulating services (thermal and disease regulation) and cultural services (aesthetic value, recreation, education and learning). The overall ecosystem services provided by the roof gardens were mostly found medium. Among these the most prominent and remarkable services were plant species diversity conservation (diversity index 4.51), thermal regulation and mental satisfaction.