Lichens are a wonderful gift of nature. Several animals and insects feed on lichens. Lichens are regarded as ecological forerunners in the colonization of rocky environments. Lichens are excellent pollutant indicators. Some important useful activities are as follows
1. Food and fodder: lichens are used as food since ancient times. Horses and swans are given dried lichens.
2. Medicines: the medicinal value of lichen is due to the presence of lichenin and some astringent substances. Bile, Diarrhoea, Fever, Nervous Disorder, Hydrophobia, and Skin Diseases are all treated with lichens. Several ayurvedic treatments contain lichens as active ingredients.
3. Dyes: Some dyes are obtained from lichens and have been used since ancient times for coloring fabrics. litmus and important acid-base indicator dye used in chemical laboratories is obtained from Roccella montagnei and Lasallian pustulata.
4. Cosmetics and perfumery: several species of lichens are a source of essential oils used in the manufacture of cosmetic soaps. lichens are important ingredients of many antiseptic creams as they have tumor-inhibiting and spasmolytic properties.
5. Pollution indicators: They are indications of air pollution and sulfur dioxide contamination.