Effects of urban land change on ecosystem service values in the Bolgoda Wetland, Sri Lanka

Understanding the effect of urbanization on urban wetland ecosystem service value (ESV) can provide scientifically sound information for urban planning and the protection of urban wetlands. This study aimed to discuss the effect of urbanization on the Bolgoda wetland, located in the Colombo Metropolitan Region (CMR), Sri Lanka. We developed a framework to evaluate the ESV changes based on land use/cover (LUC) changes between 1989 and 2021. Considering Natural Growth (NG) and Wetland Protection (WP) scenarios, we projected the future LUC changes (2030 and 2050) and evaluated the future ESV changes. The results revealed that the ESV has declined by USD 116 million/year from 1989 to 2021. The scenario analysis indicated that the ESV will continue to decrease by USD 17 million/year in 2030 and USD 35 million/year in 2050 under the NG scenario. However, under the WP scenario, the decrease would only be about USD 0.96 million/year in 2030 and USD 11 million/year in 2050, respectively. The most important ecosystem service functions are water regulation, genetic resources, food production, and climate regulation. Therefore, the local government should practice wetland management strategies to enhance the ESV of the Bolgoda wetland and other urban wetland ecosystems (UWEs) in the country.