1. Soil formation from rocks: CO2 released from lichens mixes with rainwater to produce carbonic acid. Carbonic acid corrodes the rock into small particles. The particles mix with the dead bodies of lichens to form soil.
2. Increase in water holding capacity of soil: Dead bodies of lichens form humus in soil. Humus increases soil water holding capacity and increases fertility.
3. Environmental purification: Lichens take in CO2 and release O2 in the process of photosynthesis. As a result, the atmosphere is pure.
4. Adsorption of Pollutants: Lichens require clean air free from pollutants to grow. They cannot tolerate air pollution. So lichens absorb carbon dioxide, heavy metals and other pollutants from the air.
5. Nitrogen Fixation: Lichen forming cyanobacteria (Nostoc, Anabaena) take free nitrogen from air and convert it into NH3, NO3 etc.
6. Environmental indicator: Lichen acts as an indicator of environmental pollution. If lichen grows in a polluted area, it can be understood that air pollution is decreasing in that area.
7. Enhancing the beauty of the environment: Lichens grow on exposed hills and tree barks making them beautiful. As a result, the beauty of the environment increases.
8. Primary succession: Lichens play a major role as primary succession in creating forests on rocky or rocky sites. They form the first step in plant succession, initiating the formation of forests.
9. Oxygen release: Lichens release oxygen into the environment in the process of photosynthesis.
10. Ecosystem dynamics: Components of lichen ecosystems. Animals depend on lichens. Hence lichens help in ecosystem dynamics.
11. Destructive action: Lichen growth causes decay in wood, trunks, walls, roofs, etc.