Monitoring fungal communities with the Global Spore Sampling Project

The kingdom fungi is a megadiverse group of organisms which is present in all ecosystem types. The global diversity and distribution of fungi is still largely unknown, in part due to the limitations related to traditional fruit-body survey methods, which rapidly developing eDNA-based surveys are overcoming. Global fungal eDNA surveys have predominantly been based on soil samples, which capture high species diversity, but represent only the local soil community at the site where the sample is taken. Recent work has shown that eDNA samples collected from the air with a cyclone sampler represent fungal diversity at the regional scale of some tens of kilometres around the sampling location. To test the feasibility of air sampling for investigating the global patterns of fungal diversity, we established a new initiative called the Global Spore Sampling Project (GSSP). The GSSP currently involves fifty sampling locations distributed to all continents, each location collecting two 24 hr samples per week. Here we describe the GSSP methodology, including the sampling, DNA extraction and sequencing protocols and the bioinformatics pipeline. We further report preliminary results based on 75 pilot samples from five locations, out of which three are in Europe, one in Australia, and one in Greenland. The results show highly consistent patterns, suggesting that GSSP holds much promise for systematic global fungal monitoring. The GSSP provides highly standardized sampling across space and time, enabling much improved estimation of total fungal diversity, the global distribution of different fungal groups, fungal fruiting phenology, and the extent of long-distance dispersal in fungi.