Disptaches_Lichens

Acarospora sinopica, a new park record lichen species.

James Lendemer Photo

"Other than the Smokies and a few other protected areas, lichen diversity in the East is radically different from that of a century ago," said Dr. James Lendemer of the New York Botanical Garden, as we hiked up the Noland Divide Trail out of Deep Creek. Lichens are composite organisms, usually composed of a green alga and a fungus that together can live in locations that many other forms of life cannot, such as the sun-baked exposed rock faces we were heading up the trail to find. The two parts of a lichen support each other, with the fungus providing protection for the algae and feeding off of the sugars the algae produces by photosynthesis. Lichens are named for the fungus, as often the same algal species is found in many different lichens. As we hike, we notice lichens that hang from trees like hair, bright red-tipped British soldier lichens, and leafy growths or gray "paint splotches" on tree trunks.

Lichens are incredibly diverse. On another hike up the Bullhead and Rainbow Falls trails to Mount Le Conte with Dr. Lendemer and his fellow taxonomist, Dr. Erin Tripp of the Rancho Santa Ana Botanic Garden, over 200 species were observed. More than 5,000 species of lichen and related fungi have been documented in North America, and over 800 of those have been found in Great Smoky Mountains National Park. Along with colleague Dr. Richard Harris (also of NYBG), Drs. Lendemer and Tripp have described 20 lichen species and two lichen genera that are new to science and have reported numerous geographic range extensions. Researchers have found more species of lichens in the Great Smok Mountains than in any other national park unit.

When we get to the first rocky outcropping, Dr. Lendemer starts calling out names as if he is seeing long-lost classmates at a college reunion. A patch of yellow on a rock turns out to be Acarospora sinopica, a species that lives on exposed rocks with high iron content. It is a new park record.

Dr. Tripp calls out about another unusual record. I assume she is talking about a large, leafy species at the top of the rock. But she points to an inconspicuous brown crust with tiny black dots on the rock face itself. It stood out like a stop sign to her as she walked by, but I hadn't noticed the lichen crust though I had been staring directly at it.

 

Dr. Tripp and Dr. Lendemer search a rocky outcrop on Mt. Le Conte for new lichen species.

NPS photo

Like me, most people focus on the larger fruticose (bush-like) and foliose (leaf-like) lichens. Dr. Lendemer and Dr. Tripp have taken on the task of bringing more attention to the lesser known world of crustose lichens. Understanding the diversity of lichens is vital to protecting them. Some species of lichens are found seemingly everywhere. Others are specialists--requiring rock with a particular chemistry or growing only on the outermost ends of dead branches. Many lichens cannot tolerate pollution, so areas with high ozone or acid deposition problems often lose most of their hair-like lichens (Usnea sp., etc.) and other sensitive species. Dr. Lendemer remarks that it is nice to walk through a forest with such high lichen diversity.

Dr. Lendemer and Dr. Tripp have been coming to the Great Smoky Mountains National Park since 2007 to observe and collect samples of the wide lichen biodiversity. They concentrate on species that grow in habitats and with growth forms that other scientists have generally ignored or overlooked. They are currently working on two books. Scientists will find The Lichens and Allied Fungi of Great Smoky Mountains National Park: an Annotated Checklist with Comprehensive Keys, highly useful, while both amateurs and professionals will appreciate the Field Guide to the Lichens of Great Smoky Mountains National Park.

Another goal of this project is to provide the park with a list of species found here that are rare on a global scale. This will allow park biologists to monitor the populations and follow their progress. Lichens can provide nitrogen for soils, break down rocks and dead trees, and provide homes for a large variety of animals--from insects and tardigrades to birds that use them to build their nests. We discovered that on at least one rock outcrop along the Noland Divide Trail, they appear to have provided a home for a large number of chiggers. But though we're now quite itchy, we remain undaunted in our enthusiasm for the lichens we found, many of which have never been documented in the Smokies before.

 

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