In fact, in the course of five field trips to the Smokies, Lendemer and his colleagues, including Garden curator Richard Harris, discovered that the Smokies were home to many more lichen species than had previously been known, increasing the number of recorded species there by 60 percent.
Lichens are composite organisms consisting of a fungus and an alga or another organism capable of photosynthesis. They grow on a wide range of surfaces, including bare rock and the leaves and bark of trees. Many species are sensitive to pollution and are seen as indicators of environmental health. They also serve many important functions in a healthy ecosystem.
"Lichens are critical components of terrestrial ecosystems," said Dr. Lendemer. "They're important in nutrient cycling. Animals and insects eat them and use them for shelter."
Some lichen species may even be specifically adapted to grow on certain types of trees, including ones typically found in old-growth forests. Dr. Lendemer and his collaborators found one of the new species, Arthonia kermesina (photo, right), only on large, old spruces at high elevations in the Smokies.
In addition, Brendan Hodkinson, Ph.D., who discovered two new orders of lichensSarrameanales and Trapelialesin collaboration with Dr. Lendemer, noted that lichens most likely have importance to human life in ways that remain to be discovered, such as the apparent ability of some species to fix nitrogen, an important characteristic for making soil productive for food crops.
"Since lichens produce so many different chemical compounds, there's a lot there that could be worked with," Dr. Hodkinson said. "There are definitely a lot of potential human applications that haven't been looked at."
The value of lichens for both their known and potential uses makes it important to increase efforts to find and conserve them, according to
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The New York Botanical Garden