DNA metabarcoding reveals compositional and functional differences in fungal communities among Amazonian canga formations

Fungi execute many ecosystem functions and are thus expected to contribute substantially to ecosystem stability along environmental gradients. Here, we aimed to describe the fungal communities along a vegetation gradient found in Amazonian cangas using ITS2 metabarcoding. Rupestrian canga vegetation covers ironstone outcrops from the Carajás National Forest and the Campos Ferruginosos National Park of the Eastern Amazon. We detected 3574 operational taxonomic unit sequences dominated by the phyla Ascomycota, Basidiomycota, and Glomeromycota. The taxonomic and functional groups differed among periodically inundated grasslands (GR), typical scrublands (SB), Vellozia scrublands (VL), and woodlands (WD). Saprotrophic fungi were the most abundant, occurring primarily in WD, while stress-tolerant lineages and functional groups were dominant in environments with less soil. Our results provide new insights into the fungal ecology on ironstone outcrops and shed light on the importance of these organisms in enabling growth of vegetation cover, promoting species coexistence and increasing degrees of plant diversity in these harsh environments.