Diversity of saprotrophic filamentous fungi on Araucaria angustifolia (Bertol.) Kuntze (Brazilian pine)

The biodiversity of filamentous fungi and their ecological relationships in the context of decaying Araucaria angustifolia (an endangered conifer) substrates are still mostly unknown. The present study aimed to investigate the diversity of saprotrophic filamentous fungi, based on morphological identification, associated with A. angustifolia, in addition to assessing possible saprobic/plant affinity relationship, and verifying whether the study areas and substrates affect the composition of the mycobiota. A total of 5000 substrates (decaying needles and twigs) were collected during five expeditions (2014/2015) to two areas: Sao Francisco de Paula National Forest (FLONA-SFP) and Sao Joaquim National Park (PARNA-SJ), Brazil. A total of 135 species distributed among 85 genera, 40 families, nine classes, 24 orders, three subphyla, and two phyla were identified. One new genus and five new species that were previously described, and six rare species and five species with affinity for A. angustifolia were also recorded. The twigs showed a community of fungi with greater richness and dominance. Conversely, the values of abundance, Simpson's diversity index, and evenness were lower than those determined for needles. In terms of the study areas, FLONA-SFP showed higher values of richness, abundance, Simpson's diversity index, and evenness than PARNA-SJ. Principal coordinate analysis and similarity percentage analysis showed the influence of both substrate factors and areas in the composition of the fungal communities. The presence of new, rare, and affinity-related species reinforces the study of fungi in the context of the conservation of this conifer, as these species are threatened by co-extinction.

Automated summary

This study aimed to investigate the diversity of saprotrophic filamentous fungi associated with decaying Araucaria angustifolia substrates in Brazil. A total of 135 species were identified, including one new genus and five new species. The study found that twigs had a greater richness of fungi compared to needles, and FLONA-SFP showed higher richness and diversity of fungal species compared to PARNA-SJ. The composition of fungal communities was influenced by both substrate factors and study areas.