Nature conservation in the genomic era: soil fungal diversity assessment in protected coastal Salix repens communities in the Netherlands using DNA metabarcoding

Western European coastal sand dunes are highly important for nature conservation, with communities of the creeping willow (Salix repens) considered particularly diverse. We report here the results of the first kingdom-wide fungal diversity assessment in S. repens coastal dune vegetation. We sampled soil at ten sites in an extended area of joined nature reserves of high ecological value located along the North Sea coast of the Netherlands and generated and analyzed 688,434 ITS2 rDNA sequences using 454 pyrosequencing methods. Fungal communities in Salix repens beds are highly diverse and we detected 1211 non-singleton fungal 97% sequence similarity OTUs. Our large-scale comparison along a north-south transect indicated strong correlation between soil pH and fungal community composition. Furthermore, by comparing our soil data with long-term sporocarp-based studies, we detected numerous red listed species in our samples, often from previously unknown locations. Our data indicates that some of the fungal species currently considered rare are likely more abundant than previously thought. Beside providing a wealth of information on the diversity of fungal communities and on the distribution of fungal species along the coastal dune habitats in the Netherlands, our study demonstrates the potential contribution of high-throughput soil sequencing studies to fungal mapping and the conservation of red listed fungal and plant species.