CONICET | Buscador de Institutos y Recursos Humanos

The Yungas, a system of subtropical montane forests on the eastern slopes of the Andes, reach their southern limit in northwestern Argentina. These forests are extremely diverse and, despite covering only 2% of the countrys area, they harbour about 50% of Argentinas biodiversity. Unfortunately, the Yungas are among the ecosystems most threatened by anthropogenic pressure and climatic changes. Previous mycological works in the Yungas focused on wood-decay fungi (e.g., polypores) and mycorrhizae in Alnus acuminata cloud forests, while diverse Yungas communities still remain virtually unexplored. We carried out massively parallel pyrosequencing of ITS rDNA from soil samples to provide the first kingdom-wide fungal biodiversity assessment for the Yungas. Samples were taken in 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 1839 fungal operational taxonomic units (OTUs) in total. The majority belonged to the phylum Ascomycota (52.49%), followed by Basidiomycota (18.85%), Glomeromycota (0.012%), and various zygomycete lineages (0.02%), while 24.91% showed highest similarity to other unidentified environmental sequences and could not be assigned to phylum. The distribution of the total 1839 OTUs among the major altitudinal vegetation types were as follows: 909 OTUs in the piedmont forest, 826 in the montane forest, and 929 in the montane cloud forest. Fungal communities were significantly different among all three forest types, with many OTUs showing strong habitat preference for a certain altitudinal zone. Our data offers an unprecedented insight into the fungal biodiversity of the Yungas and into the zonal changes in fungal community structure, with potential applications in conservation strategies to preserve the unique biodiversity of the Andean forests.