Lichens as Useful Organisms

Lichens exist because of a symbiotic working relationship between fungus, offering protection and structural support, and algae, giving the food from photosynthesis. Lichens have the amazing ability to retain water and because of this, ecosystems and wildlife benefit from the moisture and humidity created.

Lichens have been used and valued by both people and wildlife for centuries. Generally growing best in non-polluted areas, they serve as a refuge from predators for amphibians and insects, who hide and lay eggs in lichen. From atop hot, sunny mountain rocks to the substrates of tree bark, rocks, watersheds, soil and leaves, lichens grow both in terrestrial and aquatic landscapes around the world. These diverse organisms can be found in various areas of different weather extremes.

Throughout history native cultures and traditions have found practical and medicinal uses for lichens. Native Americans in New Mexico collected lichen to use for dye to color the yarns and fabric in their rugs and other woven materials. Usnic acid, derived mainly from the Usnea species of lichen, most often found hanging from trees, is used in antibacterial and antifungal medicines. Lichens are also used in perfumes, botanical supplements, toothpaste and even deodorant.

Many species of North America birds use lichens. The spruce grouse and wild turkey eat lichen. Warblers and Vireos use lichens in their nests, and Golden Plovers use the Thamnolia vermicularis species in their nests. The Olive-headed Weaver in Madagascar makes its nests solely from lichen in Usnea (mentioned above). In the process of constructing their nests, Hummingbirds may include soft thistle and dandelion seed fluff, along with expandable, stretchy spider silk and leafy materials, and may add a dab of pine resin as glue before a final layering of lichens around the entire outside of their nest for lightweight insulation and camouflage.

Deer, elk, antelope, cows and small mammals also utilize lichen. In southeastern Alaska mountain goats include Lobaria linita species in their diet. Northern flying squirrels use lichen Bryoria fremontii species both as nesting material and food. Two species of Bryoria consist as the primary diet of the endangered Yunnan snub-nosed monkey. During the winter season, caribou using their keen sense of smell will search for lichen to eat beneath the snow.

Lichens are extremely sensitive to habitat alteration and therefore a good indicator of non-polluted areas. The association between a large diversity of lichens and unpolluted habitats is so evident, that scientists use lichens as indicators of ecosystem continuity to help identify areas that should be protected.

Dayelle Swensson is an avid writer for the web on a number of topics. Having gardened herself for many years, she is able to advise others about a variety of things including gardening tips, lawn and tree care, watering, hose reel and keeping your home garden looking attractive and healthy.