PS 22-45 - Metabarcoding and quantitative PCR as valuable tool in detection of threatened fungal deadwood species

Abstract: In Central European forests, only a minor part of wood is allowed to undergo natural decomposition. Few protected areas include the remains of larger deadwood bodies, and thus the unique organisms associated with it. Among the latter are rare wood-associated fungi (i.e. endangered “red-list” species) associated with Abies alba deadwood, a forest tree species with a minor presence across Germany due to forest management and browsing by larger herbivores. Meanwhile, this is recognized especially in National Parks and management systems were implemented like deadwood enrichments and identification of focal sites. However, there is a great need to efficiently monitor the presence of endangered fungal species for conservational concerns and to apply strategies for the future.

In this study, we applied a metabarcoding approach to detect rare red list fungal species in deadwood logs dependent and independent of their fruiting, and monitored their distribution across the Bavarian Forest National Park investigating ~60 standing and lying Abies alba logs of different decay classes. This was accompanied by analysis of carbon and nitrogen content. Further, we developed primers for analysis of the distribution and biomass estimation of Phellinidium pouzarii – an endangered focal fungal species – using a qPCR approach.

The metabarcoding approach identified ~1,600 fungal amplified sequence variants and PERMANOVA separated the fungal communities by location and decay class (p< 0.001). Altogether 11 endangered fungal species were recorded, among them Camarops tubulina, Cystostereum murrayi, Hericium flagellum, Phellinidium pouzarii, Phellinus hartigii, Phellinus nigrolimitatus, Phlebia centrifuga and Pseudoplectania melaena. Besides monitoring fruiting bodies, this metabarcoding approach proved very useful and complemented highly the latter “classic” approach. However, one result is that surprisingly many of the endangered species were recorded only in one or very few logs and often only in one location. As many of these species were isolated for cultivation, a major strategy in the upcoming years will be the inoculation into new logs to extent the range of these fungi. This will be closely monitored using qPCR approaches. Promising was the design of new specific primers for P. pouzarii, which resulted in a new record of this species aside from known fruiting body records and might enable a more time efficient monitoring in future for this fungus. Further studies are needed that analyze the genomes and perform cultivation experiments to enlighten the ecology of these endangered species, to understand the limitations of their distribution and to provide concrete recommendations to support populations.