Biocrusts dominated by bryophytes and lichens perform important functions in dryland ecosystems but monitoring these communities can be cost prohibitive over broad scales. We explored DNA metabarcoding as a potential tool for monitoring biocrust lichen communities at a site in Washington (U.S.A.) that had already been surveyed for lichen diversity and community composition. We developed a DNA reference library using the internal transcribed spacer (ITS) region from specimens collected in the study area. We also visually estimated the abundance of lichen species or groups in 22 plots spanning a range of wildfire history and invasion by the exotic annual grass Bromus tectorum. At these plots, we collected bulk lichen community samples for metabarcoding using two approaches: small sample dishes and combined biocrust fragments collected using tweezers from all species observed. We used PacBio sequencing to simultaneously generate ITS barcode sequences for all lichen-forming fungi (LFF) present in the bulk samples, clustering similar sequences into operational taxonomic units (OTUs). Lichen communities detected visually and using DNA metabarcoding both captured a reduction of biocrust diversity and change in community composition related to the abundance of B. tectorum, suggesting that metabarcoding was able to identify the same dominant ecological pattern in biocrust lichens as visual sampling. The tweezer sampling approach captured on average 12.3 more OTUs than the dish approach and some taxa were more consistently detected by one approach or the other. After using the specimen DNA reference library to identify species associated with LFF OTUs, we determined that metabarcoding and visual sampling detected overlapping but different lichen species. Metabarcoding failed to detect common collected taxa, including: Arthonia glebosa, Candelariella spp., Enchylium tenax, Lecanora muralis, Lecidella spp., Leptochidium albociliatum, Massalongia carnosa, and Trapeliopsis glaucopholis. However, metabarcoding detected OTUs not visually observed in the genera Elixia, Lecanora, Lecanoropsis, Bacidina, Pyrenodesmia, Xanthocarpia, Trapelia, Verrucaria, and Verruculopsis. Furthermore, metabarcoding identified greater OTU diversity than expected within Diploschistes muscorum, Trapeliopsis bisorediata, and Trapeliopsis steppica. Our results suggest that metabarcoding alone or combined with visual methods could be a useful approach for monitoring biocrust lichen communities and their response to disturbance, invasion, and potential restoration.

This study describes four species of the genus Myriolecis from China. Among them, two are new to science, namely Myriolecis gigantea and M. complanata, and two are new records from China, namely M. persimilis and M. juniperina. M. gigantea can be distinguished by its conspicuous thallus, a large, dark and heavily pruinose apothecial disc, and the presence of vinetorin. M. complanata has black apothecial discs with constant and thick thalline margins, bluish-green pigmented epithecium (N + red) and the thick gelatinized paraphyses which may become submoniliform in the uppermost part. Phylogenetic analysis based on a combined 2-locus dataset [internal transcribed spacer (ITS) and mitochondrial small subunit (mtSSU) sequences] revealed that the four species are members of Myriolecis, and they were compared with morphologically similar and related species of this genus. In addition, detailed descriptions, illustrations, habitats, locality data and color photos of these species are provided.

Circinaria weii Q.Ren from China is described as a species new to science. The species is characterized by the crustose, olive-brown to dark olive, commonly fertile, epruinose thallus; the thallus displays angular, convoluted to oblong areoles, forming short lobes at its periphery; punctiform to elongate pseudocyphellae; short (5–9 mm) conidia, and the lack of lichen substances. Phylogenetic analysis indicates that the new species is closely related to Circinaria arida and C. maculata. A detailed description and figure for the new species are given, and a key to the species of Circinaria from China is provided.

Based on morphological characters and phylogenetic analyses, Pseudotrachypus motuoensis is described as a new species based on a specimen collected from Motuo County, SE Xizang, China. This new species is well distinguished from other congeners by terete-foliate plants, stem leaves and branch leaves distinctly differentiated, with stem leaves ovate-oblong, with subpiliferous apices, and branch leaves oblong, concave, with apiculate apices.