TDA-IME Project Final Report June, 2013 It is clear that there had already been significant losses of mangrove forests before coastal shrimp farming became widespread in Asia. This is borne out by the history of mangrove conversion in Thailand, where aquaculture only became the main cause of mangrove loss after 1980; prior to this date, salt farming, agriculture and coastal infrastructure accounted for about two-thirds of the mangrove area lost (Aksornkoae, 1983). In other countries, however, most notably in Indonesia, Philippines and Viet Nam, extensive integrated mangroveaquaculture systems have operated for much longer and they have enjoyed something of a revival more recently as pollution and disease have caused repeated economic losses for intensive shrimp farmers. The integrated mangrove-aquaculture systems do not fully convert the mangroves, but actually depend on conserving the mangrove ecosystem services that shrimp and other aquatic species depend on in nature (albeit in a highly modified and somewhat degraded form). Unlike conversion, mangrove degradation per se is often a slow process - taking place over several years, or longer, from a combination of various direct and indirect causes. The result is that there are many examples in Asia of apparently intact mangrove forests included in national inventories that are actually moderately to severely degraded. The common causes of mangrove degradation country to country are: 1. Inadequate legal instruments, or their lack of enforcement, to prevent in situ 59 mangrove degradation. 2. Disregard for the environmental health of mangroves by ex situ aquaculture, industrial and urban developments situated adjacent to mangroves. 3. Lack of regulations, or their enforcement, to prevent land-based pollutants entering mangrove ecosystems. 4. Diversion of freshwater for agricultural use before it reaches the coast. 5. Local to transboundary transportation of garbage by tides and currents into mangrove forests. 6. Poverty-related dependency on exploiting mangrove resources for food, fuel wood and timber by local communities, leading to overexploitation. 7. Demand from coastal aquaculture farmers for juvenile shrimps, crabs and fish of mangrove-associated species; and demand for other mangrove species as aquaculture feed. 8. Market-driven demand for mangrove-associated aquatic species regarded by suppliers and consumers as high value “seafood” (e.g. mud crabs, mangrove oysters, some penaeid shrimp and grouper species). 9. Low awareness among government, private sector and the general public about the importance of mangrove ecosystem services and of maintaining ecosystem integrity. 10. Coastal erosion aggravated by climate change impacts (causing both degradation and habitat loss). And, paradoxically: 11. Mangrove rehabilitation practices selected on the basis of low cost and short term efficiency may create crowded monospecific mangrove plantations that are more vulnerable to pest infestations. The fundamental causes of mangrove degradation are population growth and poverty; lack of capacity or will to enforce mangrove conservation and environmental protection measures; and poor public awareness of the indirect economic values of mangrove ecosystems. Scientific Research and Knowledge Management It would be misleading to claim that the body of knowledge on mangrove ecosystems is weak; in fact it is quite substantial - at least in relation to the main plant and animal
Transboundary Diagnostic Analysis of Indochina Mangrove Ecosystems
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