In this article we will discuss about the economic importance of lichens.
1. Certain species of lichens are valuable sources of food. Most important of these are the fruticose lichen Cladonia rangiferina (Reindeer Moss) and other tundra lichens which serve as food for reindeer, caribou, musk ox and other wild animals of the Arctic tundra zone.
A few species have been used as food by man. One of the rocky lichens is still regarded a delicacy in China and Japan. A species of Parmelia is prized as food in Southern India. Cetraria islandica (the Iceland Moss) and Lecanora esculenta are the other edible species.
The edible lichens are harvested and dried for human consumption or as fodder for cattle, swine and horses. The lichens, however, have little nutritive value.
2. The traditional use of lichens in the preparation of dyes deserves a special consideration. The fungal components of certain species of lichens produce coloured pigments that have been used for centuries as dyes in colouring fabrics and paints. One of these is orchil.
It is a blue dye formerly used to dye woollens. Litmus is another important and widely used dye in chemical laboratories as an acid-base indicator. It is obtained from Rocella montaignei.
Besides these, there are many other brown and yellow dyes. The use of lichens as a commercial source of dyes has, however, been abandoned in favour of synthetic dyes.
3. Medicinal use:
A few species of lichens have been used in the medieval times as a cure for jaundice, fevers, diarrhoea, epilepsy and various skin diseases. The chief among them were Peltigera camana, Lobaria pulmonaria and Everina.
The supposed medicinal benefits of lichens are now known to have no scientific basis. Recently a yellow substance usnic acid has been found in a species of Usnea, Cladonia and certain other lichens.
It is a broad spectrum antibiotic useful in the treatment of various infections. It is used in the preparation of ointments for wounds and bums. A mucilaginous substance obtained from Cetraria islandica (Iceland Moss) is used as a laxative.
4. The sweet-scented thalli of some lichens are used in the manufacture of dhup, hawan samagris and other perfumeries. A lichen popularly known as an Oak Moss is still used as a fixative for perfumes in Southern Europe.
5. Some lichen species synthesize and yield specific organic compounds commonly called lichen acids. These are useful in identification and classification of lichens.
6. Lastly the lichens play an important role in nature in initiating soil formation. They secrete organic acids which gradually dissolve and disintegrate the rocks over which they grow. The rock particles with the dead organic remains of thalli form substrata fertile enough for other plants to grow subsequently.
7. Lichens with blue-green algal phycobionts (Cyanophycophilous lichens) play an important role in providing fixed nitrogen in certain ecosystems such as deserts covered with crusts of soil lichens.
8. Lichens serve as indicators of air pollution. Lichens grow merrily exposed to air and light and completely shun the smoky polluted atmosphere of centres of heavy industry.