Our nation’s public lands and other protected areas play a critical role in preserving natural habitats, communities, and biodiversity. Often these lands are located in geologically and ecologically important areas, or act as corridors that connect broader landscapes important for migration or dispersal. However, it is estimated that 80-90% of species diversity in national parks is currently unknown. This is a crucial knowledge gap, as land managers require baseline information such as biodiversity inventories in order to know what species are present on their lands. Given how climate change is already affecting habitats and communities, this information allows managers to create plans to protect and monitor species and their populations over time.
A recent study by Abigail Robison, Pierce Adams, and Steve Leavitt, all of the Department of Biology at Brigham Young University, sought to address this gap by surveying lichens at Bryce Canyon National Park, where no such inventory had ever been conducted.
Lichens are a symbiosis between a fungus and cyanobacteria. The fungus provides a protective housing from radiation, erosion, and desiccation; in exchange, the cyanobacteria provide simple sugars produced during photosynthesis. Lichens reproduce vegetatively (by fragmentation) or sexually, through the production of spores dispersed by wind or water. Lichens come in many sizes, forms, and colors. Some species are drab, while others are brilliantly colored teal, yellow, orange, or red. Some grow as a crust on rock, others are flaky or intricately branched, others form delicate cups or rings. They can grow on many surfaces, including rock, bark, soil, and human-made surfaces, and are one of the most widespread and resilient organisms on the planet, found on every continent and in nearly every habitat from tidal coastlines to alpine ridgelines and from tropical rainforests to arid deserts.
For their survey, the BYU researchers collected samples from three sites at Bryce Canyon ranging from 6,920 to 8,330 in elevation: An arid mixed shrubland in Claron limestone; a mixed mountain shrubland on sandstone and mudstone; and a mesic mixed conifer forest on the eastern edge of the Paunsaugunt Plateau. The team collected a sample of each lichen species encountered from the three sites. In the laboratory, they used DNA metabarcoding to taxonomically classify species.
The team documented a total of 215 lichen-forming fungal species across Bryce Canyon. The highest elevation (mixed conifer) site had the most unique species (45). No more than 20% of species were shared across the three study sites. “The limited overlap between collection sites indicates that Bryce Canyon harbors greater diversity than initially thought,” write Robison et al. The researchers also documented a number of sensitive lichens, including Usnea spp. (“old man’s beard”) and Ramalina sinensis, as well as several species previously undocumented in the western United States.
Because they are slow-growing and sessile, lichens are sensitive to climate and can act as indicators of habitat quality. Different species show different tolerances to climatic conditions, so lichen presence or absence can provide insight into land-use changes. Over time, lichens also accumulate atmospheric pollutants. Chemical analysis of samples, therefore, can reveal air quality status and trends. Also, lichens often contain chemicals or colorful pigments (such as orange xanthophyll), which act as protection from ultraviolet radiation from the sun. Many of these compounds have antibiotic properties, or may have medical applications.
The researchers conclude that Bryce Canyon “harbors unique and a previously unrecognized high level of lichen diversity,” with diversity likely higher than their data show, but more research is needed to fully understand the distribution of lichen species at the park. Co-author Dr. Steve Leavitt is a member of the Escalante River Watershed Partnership, which he is advising about lichen inventories to be conducted on the Dixie National Forest.
Kevin Berend, Conservation Programs Manager
[Image credit: Nyusha Svoboda via Unsplash]
