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41,652,000 Yen (FY1994 14,030,000 Yen)
We studied of mangrove animals, and analyzed the geographical change, physicochemical condition of water and growth line of shell to clarify the present condition of Matang mangrove forest in Malaysia during 1992-1994. We also surveyed benthic animals and physicochemical factors in mangrove forest of Iriomote Island to compare with Matang. Diversity of animal species and/or abundance of the animals on and around cutover area were less than that in matured mangrove forest. Sedimental study in Matang mangrove forest showed that the mangrove stratum accumulates to 2.8m underground. The northern and southern parts of Matang area are expanding in contrast to the central area which is shrinking in recent years, and about 0.5% of total mangrove area was lost during the last decade. Physicochemical analysis of water suggested that NH3-N was supplied from mangrove forest to river and NO3-N was flowed from river to the mangrove forest, and several nutritive substances flowed out from cutting area to river. Investigation of stable isotope showed that animals inhabiting the mangrove forest mainly depend on terrestrial ecosystem, whereas the mud flat animals depend on aquatic ecosystem, and some fishes migrate from the other specific area to channels in mangrove forest. Measurement of growth line of shells showed that about 50 % of Anadara granosa collectcd in the area were less than 1 year old and the rest were 1 year old. The shells had some obstacle rings from January to March, which suggested the weather condition affected growth of the shell. As the mangrove felling gives various effects on animals depending on the wetland ecosystem, we preliminarily discussed conservation of the wetland biodiversity; i.e., allocation and size of areas harvested, and the designation of a protectcd area.
Malaysia, mangrove, biodiversity, benthos, stable isotope, diatom