How Lichens such as Reindeer moss work as an environment Indicator?

Lichens are extremely vulnerable to habitat alteration, so habitats with the highest lichen species diversity are the remnants of ancient forests and other undisturbed ecosystems. The association between high diversity of lichens and pristine habitats is so clear that scientists use lichens as indicators of ecosystem continuity — to help them identify areas that should be protected. Certain lichen species grow primarily (or even exclusively) in undisturbed habitats. Most lichens are extremely vulnerable to air pollution. When lichens disappear, they give early warning of harmful conditions. Scientists are using lichens to monitor air quality often compare current lichen inventories with past records.

Reindeer mosses were originally named for their value as a food source for reindeer and caribou in the plant’s northern range. Reindeer moss is really a lichen – a combination of a fungus and an alga, which share a symbiotic relationship and form a new plant. A short, stubby ground cover grows in pillow-like mats in sandy soil. There are about 40 species in the southeast, which range in color from gray-green to green-yellow to just gray. Because the common forms of reindeer moss are nitrogen fixers, they help form new soil, stabilize eroding sand, and create habitat for other plants and animals. The plant has the ability to absorb moisture and nutrients from the air through cells on its surface. However, this makes reindeer moss susceptible to pollutants in the environment. It is sometimes used as an indicator of environmental health.

Native Americans relied on the moss as a survival food in hard times. It is low in protein, but high in carbohydrates and vitamins A and B. It was also used in powder form to thicken soups, stews and desserts.

Reindeer moss is spongy and rubbery when moist, but becomes dry and brittle in times of little rain and will crunch if stepped on. It is slow to recover after a burn.