Ecosystem Services Assessment in the Upper Catchment of Taiwan River Basins

    This study used two hydrological models and three economic valuation models to evaluate the ecosystem services of three selected upper river catchment areas of Taiwan and compares the differences among the comprehensive ecosystem service values among them. The differences in the evaluation results could be the basis for developing the related national river catchment management policies. The hydrological balance and Thiessen polygons methods were used to assess soil water conservation in the investigated areas. The replacement cost, market price and surrogate market methods were employed to estimate the supplying, regulating, supporting and cultural service values.

     Based on the survey of the public’s preference for ecosystem services conducted by the Council of Agriculture, Taiwan in 2020, the value of each individual ecosystem service is weighted and added together to represent the comprehensive ecosystem service values. The rank of the comprehensive ecosystem service values of the the three investigated catchment areas from high to low is the Dahan river in northern Taiwan, Dajia river in central Taiwan, and the Zengwen river in southern Taiwan.

    In this study, we analyzed the calculated results and suggested possible future policy for three investigated rivers, helping to allocate limited resources to achieve best cost-effect results. According to the present study, the ecosystem service values of flood control and landslide prevention are the two most-valued indicators. However, these two service values estimated by replacement cost method was significantly higher for the Dahan river than the Dajia river and Zengwen river. In order to enhance the comprehensive ecosystem services and balance for the regional economic development, government policies should aim to increase the ecosystem service values of flood control and landslide prevention in the upper catchment areas of rivers for central and southern Taiwan.