Svampinventering i förändring : En jämförelse mellan eDNA-metabarkodning och fruktkroppsinventering i svenska gräsmarker

Sammanfattning

Grasslands are among the most species‑rich ecosystems but have undergone substantial changes over the past century. Shifts in land use have left only a small fraction of the 19th‑century grasslands remaining, resulting in more homogeneous landscapes and declining populations of grassland specialists. Restoration efforts are therefore crucial to counteract ongoing biodiversity loss, a goal emphasised in the EU Nature Restoration Regulation. A key challenge is how biodiversity in grasslands should be surveyed and monitored. Traditional surveys have focused primarily on vascular plants, even though fungi constitute a major component of grassland biodiversity. Fungi are a challenging group to survey because they are only visible when producing fruiting bodies. In recent years, environmental DNA (eDNA) metabarcoding has increasingly been used to assess fungal communities, offering the possibility to detect taxa independently of season and requiring only a single field visit. The aim of this study was to evaluate how well eDNA metabarcoding corresponds with traditional fruiting body surveys in Swedish grasslands, with a particular focus on the number and identity of grassland fungi and their red‑listed species. In addition, differences in survey effort in fruiting body surveys and differences in eDNA sample processing were examined in terms of the number of detected taxa. The study was based on DNA sequences from soil samples and field protocols from fruiting body surveys in 32 Swedish grasslands at different stages of restoration. The results showed that each additional hour of fruiting body surveying yielded approximately 17 additional taxa. Separately analysed eDNA subsamples produced higher taxon richness than pooled subsamples. Overall, eDNA detected more unique taxa than fruiting body surveys, with a median of 20,5 additional taxa per site. For grassland fungi, eDNA detected a median of seven more taxa per site. The overlap in species composition between the two methods was consistently low, indicating that the two methods detect separate and only minimally overlapping fungal communities. eDNA detected more red‑listed grassland fungi than fruiting body surveys, but only one species overlapped between methods at the same site. These findings align with previous studies and show that eDNA is an efficient complementary tool, while traditional fruiting body surveys remain essential for obtaining the most complete picture of local fungal diversity.