Mention the economic importance of lichens.

Explanation

1. Lichens secrete organic acids like Oxalic acids which corrodes the rock surface and helps in weathering of rocks, acting as pioneers in xerosere.
2. Lichens are sensitive to air pollutants and are considered as pollution indicators.
3. Cladonia rangiferina (Reindeer moss) is used as food for animals living in Tundra regions.
4. Usnic acid produced from lichens show antibiotic properties. (Note: (Any three points).