Valuing Mangrove Conservation in Southern Thailand

Study Number:

52

Author:

S. Sathirathai & E. B. Barbier

Abstract:

Mangroves are ecologically important coastal wetland systems that are under severe threat globally. In Thailand, the main cause of mangrove conversion is shrimp farming (aquaculture), which is a major source of export income for the country. However, local communities benefit from many direct and indirect uses of mangrove ecosystems and may have a strong incentive to protect these areas, which puts them into direct confrontation with shrimp farm operators and, by proxy, government authorities. The article examines whether or not the full conversion of mangroves into commercial shrimp farms is worthwhile once the key environmental impacts are taken into account. The estimated economic value of mangrove forests to a local community is in the range of $27,264 – $35,921 per hectare. This estimate includes the value to local communities of direct use of wood and other resources collected from the mangroves as well as additional external benefits in terms of offshore fishery linkages and coastline protection from shrimp farms. The results indicate that, although shrimp farming creates enormous private benefits, it is not so economically viable once the externalities generated by mangrove destruction and water pollution are included. There is also an incentive for local people to protect mangroves, which in turn implies that the rights of local people to guard and protect this resource should be formally recognized and enforced by law.

Main Results and Conclusions:

• The rate of Thailand mangrove habitat loss in 2001 was 6,037 ha per year, primarily due to shrimp farming (aquaculture) (110).
• This study focused on the more than 100-year-old Tha Po village to evaluate the local community’s attachment to a remaining section of 400 ha of mangrove habitat. This, in turn, helped determine the value of the mangrove ecosystem. Tha Po relies heavily on the surrounding mangrove forest for forest resources and protection from storm surges (111).
• Valuation of mangrove goods and services to the villagers of Tha Po are as follows (in $US per ha), and are based on a 20-year timeline:
  • Total direct use value (timber and non timber products):
    10% discount rate – 822.59
    15% discount rate – 632.37
    *non timber products include: fish, shrimp, crab, mollusks, and honey
  • Total indirect use value (off-shore fishery linkages & coastal protection):
    10% discount rate – 35,920.98
    15% discount rate – 27,264.13

• The above values for the Tha Po mangrove forest are low and high estimates for this mangrove ecosystem. Indirect benefits of mangrove ecosystems are necessary to include in valuating these ecosystems, but are harder to accurately monetize in comparison to directs goods. Therefore, the total indirect use value given above should be considered the high estimate whereas the total direct use value should be considered the low estimate (120).
• The study indicates that if shrimp farmers were forced to pay external costs associated with shrimp farming (i.e. water pollution, deforestation/soil damage, replanting costs etc.) and receive lower subsidies, then shrimp farming would not be economically feasible) (118, 120).