Ecological Compensation Standard of Trans-Boundary River Basin Based on Ecological Spillover Value: A Case Study for the Lancang–Mekong River Basin

Ecological compensation is an effective means to solve the conflict of interests among trans-boundary river basin countries. How to determine the ecological compensation standard is the core of ecological compensation. On the basis of the emergy synthesis method, we developed an emergy-water resources ecological footprint model for trans-boundary river basin countries. Based on the calculation of ecosystem service value and consumption ecological value of trans-boundary river basin countries, the ecological spillover value of each basin country is obtained. From the perspective of supply and consumption, the ecological compensation standard in basin countries is determined by judging the supply and consumption status of ecological services and combining with the willingness to pay for ecological compensation. Taking the Lancang–Mekong River Basin as an example, the results show that (1) the ecosystem service value of the Lancang–Mekong River Basin countries from high to low is Laos, Cambodia, Thailand, China, Vietnam, and Myanmar; (2) in terms of ecosystem service value consumption, the order from high to low is Thailand, Cambodia, Vietnam, China, Laos, and Myanmar; and (3) Thailand and Vietnam, located in the lower reaches of the basin, belong to the consumers of ecological services, and based on the actual willingness to pay, they need to pay $46.913 billion and $1.699 billion, respectively.