FUNGAL SUCCESSION IN Nothofagus dombeyi

Abstract

The experiment was performed in two sites of Nahuel Huapi National Park: nearby Lake Gutiérrez and Quetrihué Peninsula. The method used was direct observation on sterilized leaves previously incubated in between leaf-litter on special traps. Leaves were observed in the laboratory monthly during two years, determining tbe presence and relative frequence of fungi sporulating in both urfaces. Data obtained from both sites were used for preparing double entrance tables with taxa grouped according to Mueller-Dombois and Ellenberg (1974) method. As a result six groups of species were disitnguished; GROUP 1 represent the pioneers in the succession on fallen leaves, with Zoellneria eucalypti as dominant. GROUP II is formecl by an enclophytic fungi, Coleophoma cylindrospora and clandosporium. cladosporioides, both considered here primary saprophytes. GROUP III does not show a successional pattern and is composecl by species of diseontinuous appearence originatedin soil: we call these fungí invaders of the leaf-litter. There are Paecilomyces sp. and Acremonium sp. GROUP IV is dominatecl by Trichocladium opacum, which is an aggressive and competitive primarry saprophyte due its complex enzimatic activity. GROUP V is represented mainly by Ascomycetes, accompanied in some cases by a few aeroaquatic fungi. The fonner colonizes the leaves for a long period and can be considered secondary sapro¡phytes. GROUP VI is formed by soil and predator fungí as Monacrosporium gephyropagum and Mucor circinelloides. After 4 years and 10 month apparently the succession did not reach the "climax" state, because only about 70 % of the species found in natural leaf-litter have been detected. There is a certain coherence between SUCCESSIONAL GROUPS and SEASONAL GROUPS, th latter was reported in a previous paper.