Lichens are fascinating organisms because they aren’t just one species—they are a symbiotic partnership between a fungus and an alga (or sometimes a cyanobacterium).
The fungus provides structure and protection, while the alga/cyanobacterium produces food through photosynthesis.
This cooperation allows lichens to survive in extreme environments where few other organisms can live.
Here’s how they play an important role in ecosystems:
1. Pioneers in Harsh Environments
Lichens are often the first organisms to colonize bare rocks, deserts, and arctic tundra.
They slowly break down rock into soil by releasing acids and trapping organic material, making it possible for mosses and plants to grow later.
2. Soil Formation and Stabilization
By contributing organic matter and trapping dust, lichens help form soil.
In arid areas, lichens form biological soil crusts that prevent erosion and hold moisture.
3. Food Source
Reindeer and caribou rely on lichens (especially reindeer moss, which is actually a lichen) during harsh winters.
Small animals and insects also feed on lichens.
4. Habitat and Shelter
Lichens provide microhabitats for insects, mites, and small invertebrates.
Birds use lichens in nest-building because they provide camouflage and insulation.
5. Nitrogen Fixation
When lichens contain cyanobacteria, they can convert atmospheric nitrogen into forms usable by plants. This enriches ecosystems, especially in nutrient-poor areas.
6. Air Quality Indicators
Lichens are very sensitive to air pollution, particularly sulfur dioxide and heavy metals.
The presence or absence of lichens is used to monitor air quality and environmental health.
7. Contribution to Global Cycles
Lichens influence carbon and nitrogen cycles by fixing carbon through photosynthesis and, in some species, nitrogen through cyanobacteria.
In boreal forests and tundra, this plays a big role in ecosystem productivity.
