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National parks and other federally designated natural areas play critical roles in preserving unique habitats, communities, and biodiversity. However, in the United States, it is estimated that 80–90% of species diversity in national parks is presently unknown. Therefore, contemporary biodiversity inventories are critical for conservation, management and establishing baselines for future comparisons. Ongoing efforts to characterize lichen diversity highlight diverse and robust communities in a number of national parks in the USA. In arid regions of the western USA facing ecological transformations, lichens can play a pivotal role for monitoring these changes. Lichen diversity in Bryce Canyon National Park (BRCA) in southern Utah, USA remains nearly completely uncharacterized, despite nearly 100 years as a federally protected area. Our study aims to provide a critical perspective into the lichen diversity of BRCA. Using a metabarcoding community sampling approach, we documented 215 candidate lichen-forming fungal species distributed across ecologically distinct sites in BRCA. At each sampled site, species richness ranged from 104 to 133 species, with no more than 20% shared species among the three sites. The limited overlap between collection sites suggests that BRCA harbors greater diversity than initially thought. We document a number of sensitive lichens, particularly Usnea spp. and Ramalina sinensis, that should be monitored as air pollution, land use, and impacts of climate change affect biological communities in the park. The inventory also includes unknown species and other species that have not been documented in the western USA. While our DNA-based inventory highlights strikingly rich lichen diversity, future voucher-based collections will be essential for robust taxonomic determinations. [ABSTRACT FROM AUTHOR]

The manna lichens, a group of vagrant species with subfruticose and subfoliose thalli in the genus Circinaria Link, have received attention for millennia. Here, a new manna lichen species, Circinaria nimisii sp. nov. (Megasporaceae), is described and illustrated. This vagrant lichen is found on Mount Olympus in Greece and is the fourth known manna lichen in Europe. The new taxon is characterized by its subfruticose, densely-branched thallus with a muddy, earthy colour, whitish pseudocyphellae on tips of branches, mature apothecia distinctly adnate to stipitate, and paraplectenchymatous cortex tissue. Molecular sequence data from the standard barcoding marker (nrITS) also corroborate the distinction of this species from closely related congeners. Finally, Agrestia zerovii , previously known only from its type locality in Ukraine, is proposed as a new synonym of Circinaria hispida. [ABSTRACT FROM AUTHOR]

Species of lichen-forming fungi (LFF) display an array of geographical distribution patterns. Among the broadly distributed lichen-forming fungal species, the degree of reproductive isolation and genetic substructure among populations varies widely, in some cases masking unrecognized diversity or meaningful biogeographical patterns. Lecidea atrobrunnea (Raymond ex Lam. & DC.) Schaer. s. lat. (Lecideaceae) is a widespread species complex that has been studied for over two centuries since its initial description. The diversity of the L. atrobrunnea group is highest in western North America, where a dizzying array of morphologies and chemistry can occur at local scales. Here we investigate whether the assumed cosmopolitan distribution of L. atrobrunnea s. lat. is an artifact of taxonomic limitations and masks biogeographical patterns in this species complex. To address these questions, we compiled sequence data from the standard fungal barcoding marker (ITS) for over 100 specimens within this complex, in addition to genome-scale data from a subset of these representing over 1600 single-copy nuclear genes spanning over 3 Mb of the genome. Our study corroborates the perspective that the morphologically and chemically variable Lecidea atrobrunnea group reflects a complex of distinct species-level lineages, with 42–83 candidate species inferred from the ITS region and high levels of diversity inferred from a subset of specimens using genome-scale data. However, both phenotype- and molecular-based species boundaries remained unsettled, with the most common nominal taxa recovered as highly polyphyletic and with conflict among different molecular species delimitation approaches. Our study also highlights the potential for geographically restricted species, with fascinating biogeographical patterns, challenging, in part, the assumed cosmopolitan distribution of L. atrobrunnea s. lat. This study provides valuable direction for future research that will be crucial in understanding diversification and establishing a robust taxonomy for this well-known species complex. [ABSTRACT FROM AUTHOR]

DNA barcoding approaches provide powerful tools for characterizing fungal diversity. However, DNA barcoding is limited by poor representation of species-level diversity in fungal sequence databases. Can the development of custom, regionally focused DNA reference libraries improve species-level identification rates for lichen-forming fungi? To explore this question, we created a regional ITS database for lichen-forming fungi (LFF) in the Intermountain West of the United States. The custom database comprised over 4800 sequences and represented over 600 formally described and provisional species. Lichen communities were sampled at 11 sites throughout the Intermountain West, and LFF diversity was characterized using high-throughput ITS2 amplicon sequencing. We compared the species-level identification success rates from our bulk community samples using our regional ITS database and the widely used UNITE database. The custom regional database resulted in significantly higher species-level assignments (72.3%) of candidate species than the UNITE database (28.3–34.2%). Within each site, identification of candidate species ranged from 72.3–82.1% using the custom database; and 31.5–55.4% using the UNITE database. These results highlight that developing regional databases may accelerate a wide range of LFF research by improving our ability to characterize species-level diversity using DNA barcoding. [ABSTRACT FROM AUTHOR]

Biomonitoring studies evaluating air quality via airborne element accumulation patterns in lichens typically control variability by focusing on narrow geographic regions and short time windows. Using samples of the widespread "rock‐posy" lichen sampled across the Intermountain Region of the United States, we investigate whether accumulation patterns of generic pollution sources are detectable on broad geographic and temporal scales. We develop a novel Bayesian multivariate receptor modeling (BMRM) approach that sharpens detection and discrimination of candidate pollution sources through (i) regularization of source contributions to each sample and (ii) incorporating estimated lichen secondary chemistry as a factor. Through a simulation study, we demonstrate a distinct advantage in shrinking contributions when they are truly sparse, as would be expected with heterogeneous samples from dispersed collection sites. We contrast analyses employing both standard and sparse BMRMs, and positive matrix factorization (PMF). The sparse model better maintains source identity, as specified though informative prior distributions on elemental profiles. We advocate quantitative profile matching, which reveals that PMF primarily captures variations of the baseline profile for lichen secondary chemistry. Both PMF and BMRM results suggest that the most detectable signatures relate to aeolian dust deposition, while spatial patterns hint at sporadic anthropogenic influence. [ABSTRACT FROM AUTHOR]