Mycota of the Andean Yungas forests: assessments of fungal biodiversity and habitat partitioning in a threatened ecosystem.

GEML, J.; NOUHRA, E.; WICAKSONO C.; PASTOR N.; FERNANDEZ L.; BECERRA A.

Congreso; Mycological Society of America Annual Meeting; 2012

The Yungas, a system of subtropical montane forests on the eastern slopesof the Andes, reach their southern limit in northwestern Argentina. These forestsare extremely diverse and, despite covering only 2% of the country´s area, theyharbour about 50% of Argentina´s biodiversity. Unfortunately, the Yungas areamong the ecosystems most threatened by anthropogenic pressure and climaticchanges. Previous mycological works in the Yungas focused on wood-decayfungi (e.g., polypores) and mycorrhizae in Alnus acuminata cloud forests, whilediverse Yungas communities still remain virtually unexplored. We carried outmassively parallel pyrosequencing of ITS rDNA from soil samples to provide thefirst kingdom-wide fungal biodiversity assessment for the Yungas. Samples weretaken in the three major forest types along an altitudinal gradient: the piedmontforest (400-700 m asl), the montane forest (700-1500 m asl), and the montanecloud forest (1500-3000 m asl). Using a 97% similarity cut-off value, we delimited1839 fungal operational taxonomic units (OTUs) in total. The majority belongedto 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 sequencesand could not be assigned to phylum. The distribution of the total 1839OTUs among the major altitudinal vegetation types were as follows: 909 OTUsin the piedmont forest, 826 in the montane forest and 929 in the montane cloudforest. Fungal communities were significantly different among all three foresttypes, with many OTUs showing strong habitat preference for a certain altitudinalzone. Our data offers an unprecedented insight into the fungal biodiversity ofthe Yungas and into the zonal changes in fungal community structure, with potentialapplications in conservation strategies to preserve the unique biodiversityof the Andean forests.