Succession of fungi associated with decomposition of leaf litter in tropical evergreen forest (north-eastern Thailand)

Abstract

The richness and diversity of filamentous fungi associated with the decomposition of leaf litter of three tree species (Castanopsis accuminatissima, Styrax benzoides, and Dipterocarpus (grancilis) in evergreen tropical forest in the northeast of Thailand were studied at 6 and 12 months after leaf fall. A total of 125 taxa were identified through examining 4, 362 isolates. These comprised 6 species of Zygomycetes, 19 species of Ascomycetes, 62 species of Deuteromycetes, and 38 taxa of unidentified sterile mycelium. Each decaying stage of leaf litter had a different composition of taxonomie groups. The average percent similarity between fungi assemblages of different species litter and of decomposition stage ranged between 37-44% and 6-13%, respectively. The majority of fungal taxa found had a low frequency of occurrence. Six month decaying leaves had the highest number (2, 093) of fungal isolates but the fungal taxa number (35) was much lower than in freshly fallen leaves and equal to 12 month decaying leaves. The freshly fallen leaves gave the lowest number (1,103) of isolates but the number (69) of fungal taxa was much higher than that found in the 6 month and 12 month decaying leaves. The most dominant fungal taxon was Trichoderma koningii. The Shannon-Wiener diversity index showed that the initial diversity (H') of fungal taxa from freshly fallen leaves was the highest and equals to 2.9, 2.8 and 3.0 in C. accuminatissima, S. benzoides, and D. (grancilis) respectively.