Lichen is mother nature’s rock paint. Lichen is a combination of two organisms: algae and fungus. When two organisms live together, it is referred to as a symbiotic relationship. The symbiotic relationship of lichen is beneficial to both species, because the fungus provides structure for the algae, and the algae produces food through photosynthesis. Different species of lichen have different colors and structure.
Lichen is a pioneering species. When a disturbance alters an ecosystem, lichen is one of the first species to colonize an area. For example, if a fire burned through an area, lichen would be one of the first species to return after the disturbance.
Without lichen, other plant species would struggle to colonize a new area. Lichen can establish themselves on rocks with little or no detritus (organic matter). When the lichen die, they contribute detritus to the ecosystem. Once this organic matter builds up, other plants can colonize the area. In this way, lichen plays a crucial role in succession of plant communities.
When teaching students about lichen, I use a fun story to help the students remember the symbiotic relationship between algae and fungus:
“When Freddy Fungus and Allis Algae first met, they took a lichen to each other. Ever since, their relationship has been on the rocks.”