No abstract

One of the important environmental services mangroves provide is trapping suspended matter and sediments that carry trace metal(loid)s and organic waste from natural processes and human activities. Uniquely located, mangroves play a vital role in various functions, including the sedimentation, absorption, accumulation and transformation of pollutants emitted from residential areas, harbors and industrial zones before they discharge into the sea. Therefore, mangroves are considered highly efficient natural filters and a physical and biological storage sinks for pollutants, particularly metal(loid)s.However, this critical function of mangroves still receives little attention, and there has been no effort to incorporate it into existing policies. Consequently, as yet no financial mechanisms for conservation or payment for this environmental service have been put in place. In addition to the difficulty of identifying buyers, another challenge is providing evidence of a mangrove's role in improving water quality to the service users. Moreover, when the environmental service being paid for is improvement of water quality, a proper tool and methodology must be in place for assessing and monitoring this service. This document aims to provide an understanding of the scientific methodology that can be employed to demonstrate, monitor and assess mangrove-relevant environmental services by using case studies of mangroves in Hai Phong City and the Can Gio district of Ho Chi Minh City in Vietnam. In addition to previous work, this methodology evaluates the water purification services of mangroves in the context of existing policies on payment for forest environmental services in Vietnam, and discusses lessons learned, and funding requirements for effective assessment, evaluation and monitoring of the service. The findings contribute to identifying users and buyers of mangrove environmental services and developing implementation and monitoring mechanisms for payment for forest environmental services (PFES) through the application of environmental indices. The document is made in the hope that future studies can apply its methodology in other regions of the country to develop a database for evaluating the roles of mangroves throughout Vietnam.

• When it comes to mangroves in Vietnam, the payment mechanism for forest environmental services (PFES) can be applied to 8 types of environmental services: (1) carbon absorption and storage; (2) sedimentation and sludge reduction; (3) coastal erosion protection; (4) wave shielding; (5) supplying clean water, filtering heavy metals and pollutants; (6) spawning grounds provision; (7) landscape-tourism; and (8) food and ingredient provision. • There are 20 potential buyer groups that could pay for mangrove environment services in Hai Phong. These include: companies focused on dredging, sand mining, clean water, energy, banking, petroleum, entertainment, tourism, shipbuilding, air transport, and producers of agricultural, forestry and aquatic products; fishing and sea ports; those involved in the coastal economic zone; industries focused on mining and metallurgy, transportation and thermal power; dike management groups; and residential communities. While some buyer groups have expressed strong commitment to make payments (e.g. banks, energy companies, those producing agricultural, forestry and aquatic products), more research is needed to understand how willing other parties are to participate in paying for environmental services. • In Hai Phong, two of these environmental services-(1) carbon absorption and storage and (5) clean water provision and heavy metal filtration-have the largest number of potential buyers. • To develop a mechanism for payment for environmental services, four key questions must be answered: (1) Which services are being paid for? (2) Who is paying? (3) How much is the payment? and (4) What is the revenue and expenditure mechanism? Answering these will need long-term, thorough research, particularly demonstrating stakeholders use of environmental services. Based on the pre-feasibility study in 2018-2019, this policy summary answers the first two questions. The last two will be answered in another policy brief, once the study is complete in 2020. CIFOR infobriefs provide concise, accurate, peer-reviewed information on current topics in forest research