FUNGAL COLONISATION OF WOOD IN A MANGROVE SWAMP

Abstract

Fungal colonisation of wood in the mangrove ecosystem was studied by submerging sterilised Balsa wood blocks (Ochroma lagopus) in Sungei Buloh Besar mangrove at three different levels, over a period of 16 weeks from June to October 1994. These wood blocks were retrieved after every thirty days for laboratory observations for marine fungi. This project was specifically designed to investigate the diversity of marine fungi in the mangroves of Sungei Buloh Besar and to establish the distribution and relative abundance of these fungi on wood under different tidal exposure. A short experiment to investigate the tolerance of Trichoderma sp. to different salinities was also conducted. From a total of 84 wood pieces, 20 species of fungi were recorded comprising 12 species of Ascomycetes and eight species of Deuteromycetes. Of these, six species of fungi namely, Halosalpheia marina, Dendlyphiella salina, Lignincola tropica, Deuteromycete No. 21, Bathyascus vermisporus and Mycosphaerella sp. are new records for Singapore. This brings the total number of manglicolous fungi recorded for Singapore to 72 species. The most abundant fungi encountered in this study were Periconia prolifica, Lignincola laevis and Aniptodera chesapeakensis. Other frequently encountered species included Lignincola tropica, Lulworthia sp.; Halosarpheia marina and Antennospora quadricornuta. The degree of fungal colonisation on submerged wood was found to be most rapid during the initial period of exposure (within the first four weeks of submersion). However, with longer periods of submersion, the species diversity generally declined. The results showed that fungi such as Periconia prolifica, Lignincola laevis and Aniptodera chesapeakensis were widely distributed throughout the three tidal levels, while other species showed a more narrow vertical distribution. Balsa wood supported the lowest number of fungal species compared to other mangrove wood species such as Avicennia alba, Avicennia lanata, Bruguiera cylindrica and Rhizophora apiculata which have been earlier worked on. Some species of fungi found on Balsa have been reported on the other species of mangrove wood, while others appeared on only Balsa. This may indicate some preference of fungal species for different wood types .