Ecosystem Service Value Assessment for National Key Eco-function Zones for Water and Soil Conservation

National key eco-function zones for water and soil conservation are exceptionally fragile areas in terms of their eco-environments and are also severely affected by water and soil loss. They have been a focus of attention from all sectors of society. This research assesses important ecosystem service functions and their values using such indexes as NPP, soil conservation quantity and water conservation quantity. The result indicates that the ecosystem services of China’s eco-function zones for water and soil conservation are worth 3268.90×10⁸ CNY in total, of which organic matter production accounts for 530.96×10⁸ CNY, nutrient substance circulation and storage 301.91×10⁸ CNY, carbon fixation and oxygen release 1616.16×10⁸ CNY, soil conservation 442.70×10⁸ CNY and water source conservation 816.20×10⁸ CNY. Of the four functional zones, the Guangxi-Guizhou-Yunnan Area registers the highest value of 1551.30×10⁸ CNY, and the Three Gorges Reservoir Area the lowest value of 448.15×10⁸ CNY. In terms of ecosystem service value per unit of area, the Guangxi-Guizhou-Yunnan Area takes the first place, followed by Three Gorges Reservoir Area and the Dabie Mountain Area, which are roughly equivalent, and finally the Loess Plateau Area is at the bottom.