Quantifying the Payments for Ecosystem Services among hydrologic units in Zhujiang River Basin, China based on the indicator of Optional Capacity Value

Ecosystem services (ES) are fundamental to human being’s livelihoods, production and survival. However, the spatial mismatch between ES supply and demand is a common phenomenon. Payments for Ecosystem Services (PES) provide a way to promote the complementary advantages and benefits equilibrium between ES supplier and beneficiary. At present, PES is mainly based on the tradeoff between the profit and loss of ecological conservation. The quantifying of PES mainly uses the opportunity cost of ES supplier and follows the principle of additionality, which neglects the benefits that arise from the basic (contrast to additional) ES experienced by ES beneficiary and ignores the rights and interests of ES supplier who supplies the basic ES. To resolve this problem, we proposed that we should set the value of ES experienced by ES beneficiary as the quantitative indicator of PES. Here, we introduced a new indicator (optional capacity value, OCV) to implement this idea. The ES OCV indicates the optional capacity of supporting the total value produced by human being’s economic and social activities provided by the total volume of an ES. In this paper, we calculated the ES OCV of water provision in Zhujiang River Basin (Pearl River Basin), China. Then, we discussed three scenarios of quantifying PES, based on the principles of (1) interests sharing and responsibilities bearing and (2) equal pay for equal work. The results showed that the ES OCV could describe the conditions that water resources in a hydrologic unit not only provide benefits to the hydrologic unit itself, but also provide benefits to downstream hydrologic units, and then could be a quantitative indicator for PES. This research provides a new PES scheme which would promote the coordinated development and ecological conservation among the regions with mismatch between ES supply and demand.