EPIPHYTES ASSOCIATED WITH MANGROVE VEGETATION OF REDANG ISLAND, EAST COAST OF PENINSULA MALAYSIA

摘要

The mangrove forest of Redang Island harbours many epiphytic plants; seventeen species of division Spermatophyta (monocotyledon and dicotyledon), Pteridophyta and Bryophyta in 9 families namely Asclepidiaceae, Orchidaceae. Rubiaceae. Blechnaceae, Davalliaceae. Oleandraceae, Polypodiaceae, Vittariaceae and Hnokeriaceae. In terms of species distribution. Orchidaceae and Polypodiaceae recorded a higher species number, each contributing 23.53% (4 out of 17 species) of the total number of species encountered. Based on occurrence, Dendrobium aloifolium from family Orchidaceae was dominant contributing 71.11% of all the species recorded. Endangered orchids species of southern Johore in particular Bulbophyllum blumei, B. bolryphora. B. concinnum, Dendrobiumindivisitm. D. flavidulum, D. flexile, D. kelalii. D. pensile. Eria pudica were not encountered in Pulau Redang mangrove forest. Among the mangrove trees. Rhizophora apiculalu trees support at least 15 species of epiphytic plants. While this observationmay indicated mangrove trees specificity, this may not be so as these epiphyte species were observed and found associated with terrestrial trees in the nearby lowland dipterocarp forest, clearings and rocks. Epiphytes refugia include the stilt roots, stem and branches of mangrove trees. Fifteen species (88.23%) of epiphytic plants were found on stems compared to 7 species (41.18%) on stilt roots and branches respectively. There is no clear vertical stratification in the epiphytes community. The vertical distribution ranged as low as 10 cm to a height of 18 m. However, anls-inhabited epiphyte Hydnophytum formicarium is usually at 16-18 m height on branches of Lumnitzera littorae, with exception of one that grew at 2 m height in association with Rhizophora apiculata. Orchid such as Dendrobium aloifolium. D concinnum; ferns Drymoglossum piloselloides, Drymoglossiim piloselloidcs. Pyrrosia angustata, P. longifolia. Vittaria ensiformis and bryophytcs. Distichophyltum spatulatum can grow close above and submersed during high ikies and while others, ant-inhabited plants Dischidia coccinea and other orchids Dendrobium crumenatum and Epigenium longipes can tolerate salt spray.