BOTANICAL AND ECOLOGICAL CHARACTERISTICS
SPECIES: Cladonia (Cladina) spp. | Reindeer Lichen 



GENERAL BOTANICAL CHARACTERISTICS : 
Reindeer lichens are slow-growing, long-lived, densely branched ground
lichens with short numerous outer branchelets [2].  These lichens often
form clumps or mats composed of a large number of podetia [30].  The
podetia are slender, elongated, and branched in whorls.  They are often
densely intertangled in large colonies [30].  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 [28].


RAUNKIAER LIFE FORM : 
NO-ENTRY


REGENERATION PROCESSES : 
The dispersal of reindeer lichens mainly occurs by means of thallus
fragments and to a much smaller extent by ascopores.  Wind is the most
important dispersal agent.  Reindeer lichens grow vegetatively by
annually producing new growth at the top of the podetium, which
lengthens the internode formed in previous years [2].

The podetium of Cladonia spp. passes through three growth stages.  The
first stage, called the 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.  During the second stage, called the
growth-renewal period, the podetium grows at its highest rate but dies
off at the base at a rate equal to the growth.  This stage often exceeds
100 years.  During the third stage, the 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
[25].


SITE CHARACTERISTICS : 
Reindeer lichens 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-skelatal soils.  In these environments they often occur on soil
and sometimes on rocks, stumps, and logs [19].  Cladonia arbuscula and
C. mitis are the most competitive reindeer lichens on rock [2].
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 [2].  On the Slate Islands of Lake Superior, Ontario,
reindeer mosses grow best on dry open sites.  Here, they occur more than
twice as frequently in dry regime forest types than in moist regime
forest types of the same composition and are more than ten times as
abundant in the dry types [8].

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 [2].

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 [2].

Soils and climate:  Reindeer lichens commonly occur on moist to very
dry, sandy, nitrogen-poor soils [19] on shallow humus layers or dry peat
[2].  They are adapted to a cool, moist climate.  Most reindeer lichens
avoid calcareous soils and prefer the acid humus of podzolic soils
during germination [32].  Reindeer lichens have been found on sites with
pH values ranging between 4.5 and 5.5 [32].  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 [2].

Plant associates:  Reindeer lichens are commonly found associated with
the following species:  whortleberry (Vaccinium myrtillus), rock
cranberry (V. vitris-idaea), bog blueberry (V. uliginosum), lowbush
blueberry (V. angustifolium), bog birch, sheep laurel (Kalmia
angustifolia), common bearberry (Arctostaphylos uva-ursi), black
crowberry (Empetrum nigrum), Stereocaulon paschale, and Schreber's moss
(Pleurozium schreberi) [6,7,29].


SUCCESSIONAL STATUS : 
Facultative Seral Species (C. mitis)
Obligate Climax Species (C. alpestris, C. arbuscula, C. rangiferina)

Reindeer lichens are shade intolerant [19].  Cladonia mitis is an early
to mid-seral species, while C. alpestris, C. arbuscula, and C.
rangiferina are late-seral to climax species [25]. C. mitis is generally
the first reindeer lichen to become established in postfire succession
of white spruce and black spruce stands.  This lichen dominates for 30
to 40 years and is then replaced by other reindeer lichens such as C.
alpestris and C. rangiferia.  If the canopy becomes closed, reindeer
lichens are generally replaced by the shade-tolerant mosses such as
mountain fern moss (Hylocomium splendens) and Schreber's moss [2].


SEASONAL DEVELOPMENT : 
NO-ENTRY

Related categories for Species: Cladonia (Cladina) spp. | Reindeer Lichen