Economic Valuation of Ecosystem Services Provided by Forest Ecosystems in Sri Lanka: A Study Based on 2010 Forest Cover Classification and the TEEB Database

Abstract

Ecosystem service valuation is becoming popular among the economists, ecologists, scientists and policy makers. As a result, various research, publications and programs have arisen and content of literature is developed rapidly. Even though this field of study is developing rapidly, Sri Lankan ecosystems have not yet been valued or evaluated yet in terms of economic returns. Hence, the main purpose of this study is to calculate and define economic value for each forest polygon of 2010 forest cover data base by using the value transferring approach. This data base will be an effective tool to have a fair cost-benefits analyses of development projects which are most likely planned to be implemented on forested landscapes. The value transferring approach was selected for this study considering the free availability of data and expensive and time-consuming nature of primary valuation approaches. This study includes two main analyses: an estimation of total economic value of all ecosystem services provided by forest ecosystems of Sri Lanka and an estimation of economic value of water services provided by the forest ecosystems within the Mahaweli River basin which is known as largest and longest river basin of Sri Lanka. For the first analysis, required reference values of ecosystems services were found from the equivalent biomes of TEEB database. These reference data were processed at three levels and standardized to 2019 US dollar values by following a standard procedure. These processed results regarding water services were used for the second analysis and the watershed boundaries, sub-watershed boundaries, stream network, pour points were created using Arc Map 10.8.1. According to the results of first analysis, the total annual economic value of all considered ecosystem services range from US $ 3.472 billion to US $ 138.818 billion and the estimation can be averaged at US $ 34.5 billion. Results further confirmed that mangrove forests are important and ecologically valuable by reaching to the highest per unit area annual economic value being estimated at US $ 42856 per hectare per year. The water service analysis revealed that the economic value of water services provided by all forest ecosystems within the Mahaweli river basin is US $ 67.9 million. Analysis further indicated that, US $ 11,247,073 worth of water services are produced by the 78,429 ha of forest lands within the Parakrama Samoodraya sub-watershed annually. These results of both analyses are important in future conservation and management decisions making, especially regarding identifying