Paraná river delta wetlands soil microfungi

Summary The Parana River Delta soils are affected by seasonal flooding coupled with rapidly flowing water from the Parana River and by the de la Plata River estuary tidal regime which reduces the seasonality of the Parana River regime. The present study is the first investigation undertaken to determine the fungal composition of different site soils and to evaluate if flooding and flowing water energy induced differences on fungal community. Five sites were selected and three plots at each site along a topographical gradient were examined. From all soil samples, 23041 isolates belonging to 74 taxa were obtained. Talaromyces flavus and Eupenicillium brefeldianum were the most frequent species and present with high densities. Several taxa were soil or site specific. A black yeast, Pseudeurotium zonatum, Phialemonium dimorphosporum, Eladia saccula, Phialophara spp., Aspergillus japonicus, Eupenicillium abidjanum, Arachnotheca albicans, Fusarium oxysporum and Westerdykella spp. also were common. Correspondence analysis evidenced differences among sites characterized by a set of several species. The distribution of these species shows little or no relationship with the overlying vegetation. The low microfungal biomass, the high number of taxa by 100 isolates, and the mainly dematiaceous and cleistothecial forms suggest that these soil fungal communities are disturbed. Differences among fungal communities at each site could reflect difterent disturbance conditions derived from the effect of flooding and flowing water at the Upper, Medium and Lower Parana River Delta as well as the Rio de la Plata estuary tidal regime.