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Reindeer Moss

Cladina (or Cladonia) rangiferina, C. arbuscula, C. mitis and others

Description
Habitat
Conservation
Human Uses

What are lichens? A lichen is composed of two separate organisms, an alga (or sometimes a bluegreen bacterium) and a fungus, The alga has chlorophyll and so can manufacture food, and the fungus is made up of spongy threads that support the alga and protect it from drying out. The bright green algal cells are covered by variously hued fungi, giving lichens their array of colors.

Lichens are divided into three groups: the "crustose" lichens which form a crust on rocks, the "foliose" leaf-like forms, and the "fruticose" lichens, like Cladina rangiferina, with branching growth resembling miniature trees or shrubs. About 2,000 lichen species have been identified in the Arctic, and at least 15,000 worldwide.

Lichens' suitability for arctic conditions comes from an ability to manufacture food in low temperature, low light conditions. Their tissues are not easily damaged by frost. They simply dry out and cease operations when water is scarce or light and temperatures too low. They can begin to function again even after long dormancy.

Lichens, especially reindeer moss, are the most important winter food of reindeer and caribou, typically comprising 60 to 70 percent of winter diets. The animals can smell lichens through the snow, and paw down to reach them. Although poor in protein, the abundant carbohydrates in lichens provide energy when caribou need to generate body heat and to fuel their foraging activities in winter. Few other animals feed on lichens, but caribou have microorganisms in their stomachs which enable them to digest these plants. Indeed, caribou may have evolved to fill a northern food niche that other herbivores could not occupy.

Fires are common during occasional dry vecirs in northern forests and tundras. Lichens are quite flammable and are some of the slowest plants to recover after a fire. Reindeer moss is especially slow.

Lacking water-conducting organs iike stems and roots, lichens absorb moisture and nutrients from the atmosphere through surface cells. Dissolved and airborne materials pass freely into their cells. This makes them especially susceptible to pollutants. In industrialized areas, severe atmospheric pollution has resulted iii the elimination of many lichen species. Sulphur dioxide and related chemicals are amc)ng the most widespread and damaging.

Radiation released into the atmosphere through nuclear tests or accidents is absorbed by lichens. From 1945 to 1963, when nuclear tests were conducted above ground, northern lichens absorbed radioactive strontium and cesium which passed up the food chain to caribou and people. The Chernobyl nuclear accident in Russia led to high radioactivity in reindeer meat in central Scandanavia. This will likely persist for many years, and it is feared that this single accident could destroy a regional culture based on reindeer herding.

Most people living in the north only consume their lichens after they are processed into reindeer or caribou meat. However, it is possible to eat some lichens after leaching out the acids that would cause severe intestinal irritation in people. Although mostly a survival food, lichens are commercially harvested in Scandanavia to make a powder that thickens soups and desserts. When Native people kill reindeer they sometimes eat the stomach contents of partially digested lichens and other plants. Highly nutritious, especially as a source of A and B vitamins, it is considered a delicacy.