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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]

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]