Lichens are hardy organisms that can live in some of the harshest conditions found on Earth. They are not one plant, but rather, a symbiotic combination of two -- an algae and a fungus. Lichens are an important part of the ecosystem of the Arctic tundra, where the cold, dry climate is a challenge to the survival of most plants and animals.
The Lichen Is Symbiotic
The algae in the lichen provides food for the organism through photosynthesis. Photosynthesis is a way for the lichen to capture energy from sunlight and convert it to energy for the lichen.
The fungus in the lichen provides the organism with water by retaining the small amounts of moisture in the climate, like a sponge. In dry times, the lichen can draw on the moisture it retains in its fungus component.
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The Lichen Is a Decomposer
Lichens release chemicals that work to break down rocks, creating more soil. In the tundra, there is very little plant life to do this work and lichens are of critical importance.
Though the lichen is a decomposer, it is not a parasite. Lichen often grows on trees, but does not remove any nutrients from them. The lichen is merely living on the tree without harming it.
Lichen Is a Food Source
Reindeer are some of the largest animals found in the Arctic tundra and they require a lot of food. In the coldest parts of the year, food for such animals can be scarce. In the winter months, lichens are a main source of food for reindeer. The reindeer can even smell lichens beneath a layer of snow and dig under the snow to find their food.
A few moths and beetles eat lichens too.
Environmental Threats to Lichens
Air pollution is the major threat to lichens. They are quite sensitive to pollutants in the air and are even used by scientists and environmentalists to assess air quality. In this way they are helpful in preventing pollution from worsening and protecting the delicate environments in which they grow.