XVI International Botanical Congess

Fungal succession during litter decomposition was studied in two sites of tropical humid forest in Igarassu, Pernambuco (Brazil): Dry", with Clusia nemorosa, Wet", with C. nemorosa, Riqheria grandis and Symphonia globulifera. Mature leaves were placed on the forest floor and collected once a month until decomposition (Wet": 7 months, Dry": 8 months). Fungi were isolated by particle-filtration. From each sample, 0.2 ml suspension were plated on selective media (Sabouraud, Martin, Cellulose Agar). Thirty genera and 72 species of Zygomycota (Cunninghamella, Rhizopus), Ascomycota (Chaetomium, Eupenicillium), and Deuteromycota were identified. Penicillium, Trichoderma and Aspergillus were common during all periods, yeasts appeared at the end of decomposition. Typical soil fungi were themajor component. The Sorensen index gave 78 % similarity between both sites. Edaphic and abiotic factors contribute to the high fungal diversity.