Authors: Schlegel, Markus; Panziera, Jenny;Zengerer, Veronika;Zani, Deborah;Brännhage, Jonas;Gross, Andrin;

Fungi are indispensable for most ecosystems, but strikingly little is known about their diversity, distribution and consequently about their threat status and extinction risk. This is partly owed to the fact that fungi are difficult to monitor. Therefore, we evaluated the use of eDNA analysis of airborne spores to aid in the revision of the fungal red list of Switzerland. We collected spores on a species-rich waxcap grassland site using three different methods and analysed their genetic composition with metabarcoding. In parallel, all fruitbodies from typical grassland genera were located. The spore samples were highly diverse and contained many macrofungi with a previously evaluated conservation status. We found that threatened and data deficient categories were underrepresented compared to non-threatened categories. Precipitation had a strong influence on species composition for sampling methods that also collected rainwater. Spore analysis detected 18 of 30 locally occurring grassland species, and 17 additional putative species from the selected genera. Modeling of spore dispersal provided evidence for rapidly decreasing spore concentrations already within a few meters distance from the source fruitbodies. We conclude that spore sampling is able to capture the surrounding local diversity and contributes valuable insights in the distribution and abundance of fungi.