AQUATIC HYPHOMYCETES OF THE BUKIT TIMAH NATURE RESERVE

Abstract

A quantitative and qualitative study on the aquatic hyphomycetes of a freshwater stream in the Bukit Timah Nature Reserve in Singapore was carried out using foam samples and submerged and decaying leaf debris. The physico-chemical properties of the stream were determined and water temperature, pH and dissolved oxygen content were found to be fairly constant. Foam spora were counted under a light microscope and leaf samples were incubated in distilled water to induce sporulation of conidial fungi. Single spore isolations from foam and leaf samples were carried out. Established pure isolates were maintained on 2% malt extract agar. The total number of conidia recorded monthly ranged from 5236 to 61683 conidia per ml of foam with the highest number occurring in November and the lowest in October. Abundant species were Beltrania rhombica (57.4%), Triscelophorus acuminatus (12.5%) and Ingoldiella hamata (4.6%). Less abundant species included Triscelophorus monosporus (0.2%) and Anguillospora crassa (0.01 %). Certain species such as Anguillospora aquatica and Helicomyces sp 1 were dominant in September and November, while Beltrania rhombica, with the exception of July, appeared dominant throughout the entire period of study. A sample of foam from a stream in Pulau Tinggi was also examined. Although the number of species recorded at the Pulau Tinggi stream site was comparable to Bukit Timah, the spore density and species composition were different.