Valuation of mangrove ecosystem services based on emergy: a case study in China

The mangrove ecosystem is a very important coastal ecosystem in China. However, the mangrove area of China has been severely reduced during the past 50 years. An important reason is that their values are not adequately represented in decision-making. Often the economic valuations of mangroves include only direct uses and products of mangroves, which only represent part of the total value of mangrove ecosystem services. Using the emergy synthesis method, this paper aims at assessing the emergy value of mangrove ecosystem services in China. The emergy synthesis method can be usefully applied to value ecosystem services from a ''donor-side'' perspective. It provides an ecocentric value of goods and services based on the inputs and outputs that support a system rather than the generated outputs (ecosystem services) that are useful for humans. In this study, the amounts of ecosystem services (outputs) have been converted to a common unit using the emergy synthesis method. We present a possible perspective for ecosystem service (user-side) valuation using the emergy synthesis method (donor-side approach). The ecosystem services of mangroves in China evaluated in our synthesis include organic matter production, raw materials, habitat, disturbance regulation, waste treatment and scientific research. The results show that the total emergy value of mangrove ecosystem services in China, which covers 22,752 ha, adds up to 7.56E+08 Em$ or 33,219.71 Em$/ha. The results from the valuation of selected mangrove ecosystem services suggest that mangroves are of significant importance to human well-being.