Evaluating Edna As A Tool For Documenting Lichen Diversity

The lead author is Imke Schmitt, who was a Resident Grad Student here at the Field a while back and now associated with both of the German institutions. Lichens are an important part of forest ecosystems, but documenting their diversity requires time and substantial skills in collecting and identifying lichens, which is a factor in the completeness of inventories. DNA barcoding of individual lichen specimens and bulk collections is helping address these challenges, and eDNA methods are just starting to be evaluated as a tool for lichen surveys. This new paper assesses which species of lichenized fungi can be detected in eDNA swabbed from bark surfaces of living trees in central European forests, compared to an expert floristic survey carried out in the same plots about a decade earlier. The team studied 150 plots located in three study regions across Germany, taking one composite sample based on six trees from three species (Fagus sylvatica, Picea abies and Pinus sylvestris). The eDNA method yielded 123 species versus 87 from the floristic survey. The total number of species found with both methods was 167, of which 48% were detected only in eDNA, 26% only in the floristic survey and 26% in both methods. The eDNA contained a higher diversity of inconspicuous species. Many prevalent taxa reported in the floristic survey could not be found in the eDNA due to gaps in molecular reference databases. The authors conclude that at present eDNA has merit as a complementary tool to monitor lichen biodiversity at large scales, but cannot be used on its own, and they advocate for the further development of specialized and more complete databases.
June 21. 2024