Authors: Schlegel, Markus;Ecker, Klaus;Gross, Andrin;

The first red list of the fungi for Switzerland is currently being revised. For the three-year field campaign to gather new fungi record data, we implemented an innovative sampling design encompassing both forested and grassland areas and aiming at efficiently covering fungi occurring in common and rare habitats. The study-site selection process was based on modern sampling techniques, such as unequal probability sampling, balancing across several abiotic and biotic variables, and geographical spreading. Habitat information from the Swiss National Forest Inventory and from a novel high-resolution habitat map were incorporated. Additional sites were chosen from ‘hotspot’ areas with previous knowledge of fungal diversity. Furthermore, we will integrate data from different environmental DNA sources. During the first sampling year, 46 professional and volunteer mycologists contributed nearly 10000 fungi records originating from 108 plots. There was a trend towards higher diversity in grassland ‘hotspot’ sites compared to grassland sites from the Switzerland-wide selection. No such pattern could be detected for forest sites. A preliminary comparison of the data to the first red list campaign revealed that the new design led to higher relative numbers of red listed fungi. The new sampling design can help other countries to implement similar fungal monitoring programs.