Trade-offs of mangrove area development in the Philippines

Once only of significance to local communities, mangrove areas in the Phili ppines are now an internationally visible and highly valued resource, princ ipally as a consequence of the emergence of the shrimp culture industry. Th is has resulted in a conflict with the traditional uses of the mangrove are as, as unmodified ecosystems, including firewood gathering, thatch material (Nypa species) for homes and mangrove poles for lumber and construction ma terials, and nursery grounds for the small scale and commercial marine fish eries. In effect, mangrove forested areas in the Philippines have been stea dily transferred from a common property resource, of multiple use and benef it to a large number of people, to a private good, of single use for shrimp ponds, whose profits are narrowly channeled to the benefit of a select few . This paper examines the trade-offs of this change in mangrove area use. T he trade-offs are examined through three interlinked analyses. The first is a population dynamics model which illustrates the effect of the changes in the habitat (mangrove hectares) to the population of a single mangrove-dep endent fish species from the family Leiognathidae. The paper then applies a n assumed stock loss scenario from the model to a multiple objective benefi t analysis and evaluates the net benefits obtained under three alternatives for the mangrove area: (1) leaving the area undeveloped; (2) developing th e area for polyculture; and (3) developing the area for semi-intensive shri mp aquaculture. The procedure in the multiple objective benefit analysis is to classify the benefits to each group affected by the decision and the co nsequences or net benefits to the groups in aggregate. The results are disc ussed vis-a-vis social equity issues. (C) 1999 Elsevier Science B.V. All ri ghts reserved.