Litter Production and Decomposition of a Mangrove Forest at Ohura Bay, Okinawa
摘要
The litter production and decomposition of a mangrove forest at Ohura Bay, Okinawa were studied with the use of littertraps and litterbags. The litter production of the Kandelia candel community (PI), the Kandelia candel and Bruguiera gymnorrhiza com munity (P2) and the Bruguiera gymnorrhiza community (P3) was 8.72,10.74 and 7.73 ton/hal year, respectively. Litterfall rates were seasonal in the three communities. The first peak of litterfall in PI and P2 was in May (spring) as a result of the K. candel mature fruit fall, while that in P3 was in February as a result of the B. gymnorrhiza leaf fall. Due to typhoons, remarkable increases occurred during July and August (summer) and all com munities showed great peaks at that time. Afterward, the amount of litterfall in the three communities decreased greatly. Leaves of K. candel decomposed slightly faster than those of B. gymnorrhiza. In both species, the early decomposition (after 1 and 2 months) was great, followed by a slower decrease in dry mass for the remaining period of the experiment. The dry mass of twigs showed a much slower decrease compared with that of the leaves. The decrease in twig mass of the two species was almost entirely the result of bark loss which flaked from the wood. After 6 months decomposition, the woody materials remained generally firm and hard without obvious signs of breakdown.