CONICET | Buscador de Institutos y Recursos Humanos

The Yungas, a system of subtropical montane forests on the eastern slopes of the Andes, are both extremely diverse and severely threatened by anthropogenic pressure and climate change. Although the flora and fauna of the Yungas have been extensively studied, fungal diversity in this unique ecoregion has remained practically unknown. We carried out massively parallel pyrosequencing of ITS rDNA from soil samples taken in Calilegua National Park, in Jujuy province, Argentina. Nine sites were sampled, representing the three major forest types along an altitudinal gradient: the piedmont forest (400?700 m asl), the montane forest (700?1500 m asl), and the montane cloud forest (1500?3000 m asl). Using a 97% similarity cut-off value, we delimited 1693 and 1933 fungal non-singleton operational taxonomic units (OTUs) in the ITS1 and ITS2 datasets, respectively, with almost 50% of these identified to species and additional ca. 20% to genera. Although OTU richness values were comparable across sites, the NMDS analyses of the ITS1 and ITS2 datasets concordantly suggested that fungal communities were significantly different among the forest types, with many OTUs showing strong habitat preference for a certain altitudinal zone. Beside elevation, soil pH, soil Nitrogen and organic matter contents, and C:N ratio strongly correlated with fungal community structure as well, although these variables were also correlated to the forest type. Our data offers an unprecedented insight into the fungal biodiversity of the Yungas and into the changes in fungal community structure along an altitudinal gradient, with potential applications in conservation strategies to preserve the unique biodiversity of the Andean forests.