Cladonia species

Reindeer Lichens

BWCA Lichens

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Name:

  • Cladonia, from the Latin
  • species, from the Latin
    • Cladonia alpestris, from the Latin alpes, "mountains", and estris, "origin, habitat"
    • Cladonia arbuscula, from the diminutive of the Latin arbos, "tree"; hence "dwarf tree"
    • Cladonia rangiferina
    • Cladonia mitis, from the Latin, "ripe, soft"
  • Reindeer Moss, from its role as primary food for caribou, known in Europe as reindeer
  • Other common names include: Lichen, Reindeer Moss Lichen, Caribou Lichen

Taxonomy:

  • Also known as Cladonia stellaris (Cladonia alpestris), Cladonia sylvatica (Cladonia arbuscula)

Identification:

Description:

  • Slow-growing, long-lived, densely branched ground lichens with short numerous outer branchelets. These lichens often form clumps or mats composed of a large number of podetia. The podetia are slender, elongated, and branched in whorls. They are often densely intertangled in large colonies. The slender thalli of Cladonia rangiferina are hollow stems of very low density which are finely branched and not only have a high surface to volume ratio, but also have branches advantageously distributed to carry fire.

Distribution:

  • Circumpolar; in North America throughout Alaska, Canada, and the northern United States. south to Florida and Alabama.

Habitat:

  • Typically occur in submontane to alpine environments. They are scattered to plentiful in the open or in open-canopy forest and tundra on well-drained, water-shedding sites with shallow and/or coarse-skeletal soils. In these environments they often occur on soil and sometimes on rocks, stumps, and logs.
  • Cladonia arbuscula and C. mitis are the most competitive reindeer lichens on rock. Northern boreal forests offer climatically optimal conditions for reindeer lichen growth largely because of slow plant succession and little competition from other plant forms. Dry reindeer lichen woodlands and lichen bogs are characteristic throughout the northern boreal forest belt.
  • Cladonia rangiferina has a wider ecological amplitude than other reindeer lichens and is thus more common than the others in less favorable habitats such as wet bogs and shaded woods. It is very common all over northern Ontario, being the most widely distributed ground lichen in the area. Even in the Cladonia alpestris stands of the northern boreal forest it is considerably more plentiful than C. mitis or C. arbuscula.
  • Cladonia arbuscula prefers a moister and more shaded habitat than most reindeer lichens but is frequently found mixed with C. mitis.
  • C. mitis is commonly one of the dominants on rocks, in lichen woodlands, and on dry bog hummocks.
  • Soils and climate: Reindeer lichens commonly occur on moist to very dry, sandy, nitrogen-poor soils on shallow humus layers or dry peat. They are adapted to a cool, moist climate. High relative humidity is especially important for reindeer lichens.
  • Most reindeer lichens avoid calcareous soils and prefer the acid humus of podzolic soils during germination. Reindeer lichens have been found on sites with pH values ranging between 4.5 and 5.5.
  • Since reindeer lichens are able to take up moisture from the air, the underlying soil is not as important a source of moisture as it is to vascular plants. Reindeer lichens, therefore, can colonize and become a dominant floral element on soils too shallow or sterile to support higher plants, provided that humidity is sufficently high for lichen growth and temperature is sufficently low to inhibit competitors.
  • Shade intolerant. Cladonia mitis is an early to mid-seral species, while C. alpestris, C. arbuscula, and C. rangiferina are late-seral to climax species.
  • C. mitis generally the first reindeer lichen to become established in postfire white spruce and black spruce stands. It dominates for 30 to 40 years and is then replaced by others such as C. alpestris and C. rangiferia.
  • If the canopy becomes closed, reindeer lichens are generally replaced by shade tolerant mosses such as Mountain Fern Moss (Hylocomium splendens) and Schreber's Feathermoss (Pleurozium schreberi).
  • Reindeer lichens commonly occur as the dominant or codominant ground cover on open sites dominanted by White Spruce (Picea glauca), Black Spruce (Picea mariana), Paper Birch (Betula papyrifera), or Jack Pine (Pinus banksiana).

Fire:

  • Not well adapted to fire; highly flammable and may take 30-100 years or more to recover to prefire densities.
  • Can survive cool fires but are almost always killed by severe fire. In the black spruce zone, lichens generally burn poorly in early morning or near sunset, even on hot days, whereas at mid-day they flare up with almost incredible heat and flame. Humidity changes at ground level and dehydration appear to be the most likely factors involved. Fifty percent or more may survive if there is not much organic litter to retain the fire.
  • Recover very slowly after fire. Length of recovery time required varies with species, the extent and intensity of the fires, and site and microclimatic condition, but an average of 40-50 years appears to be a conservative estimate. Based on annual growth rates of about 1/8" for C. alpestris and C. rangiferina, it has been estimated that these species would require nearly a century to reach prefire abundance.
  • After fire the first reindeer lichen to become established is Cladonia mitis. The second reindeer lichen phase is generally dominated by C. alpestris, C. rangiferina, or C. arbuscula.
  • Highly flammable. They dry rapidly during periods of low atmospheric humidity because of the absence of roots, water storage tissues, and low resistance to water loss. Reindeer lichens resemble dead litter more than live tissue in their susceptibility to fire. Continuous mats of reindeer lichen present an uninterrupted surface along which a fire spreads. Lichen mats also accumulate tree and shrub litter which adds to the flammability.

Associates:

History:

  • Cladonia rangiferina is the badge of the Clan McKenzie

Uses:

Reproduction:

  • Dispersal mainly by means of thallus fragments and to a much smaller extent by spores. Wind most important dispersal agent.
  • Grow vegetatively by producing new growth annual at the top of the podetium, which lengthens the internode formed in previous years.
  • Podetium passes through three growth stages.
    • Growth/accumulation period, lasts an average of 10 years but can vary from 5 to 25 years. During this stage no part of the podetium dies off.
    • Growth/renewal period, podetium grows at its highest rate but dies off at the base at a rate equal to growth. This stage often exceeds 100 years.
    • Podetium degeneration period, the podetium dies off at a greater rate than it grows. This stage may also exceed 100 years.
  • Factors that probably contribute to variation in lichen growth include: the age of the podetium; prior disturbance by animals; and site conditions such as substrate, drainage, and exposure.

Propagation:

Cultivation:

Links:

Boreal border


Last updated on 11 October 1999