BOTANICAL AND ECOLOGICAL CHARACTERISTICS
SPECIES: Empetrum nigrum | Black Crowberry 



GENERAL BOTANICAL CHARACTERISTICS : 
Black crowberry is a low, creeping evergreen shrub that generally
reaches 6 inches (15 cm) in height and often forms dense mats.  The
leaves are linear to elliptic, and the lower surface is grooved to
reduce evapotranspiration in harsh climates.  Black crowberry has
inconspicuous purple flowers [2,13,47,49].

Young black crowberry plants have a strong primary root, but as the
plants age, a shallow root system with many lateral roots develops [5].


RAUNKIAER LIFE FORM : 
   Chamaephyte


REGENERATION PROCESSES : 
Sexual reproduction:  Black crowberry is classified as polygamous,
dioecious, or monoecious.  The dark-blue to black fruit is a drupe
containing six to nine nutlets [2,13,18].  Seeds are dispersed by birds
and animals [20].  Some seeds may become established under the parent,
but seedling mortality is generally high [5].  Black crowberry seeds
have been found buried beneath the soil, although only a small percent
of the seeds are actually viable [20,32].  Seeds were found in 71
percent of soil cores taken from plots near Great Slave Lake, Northwest
Territories [20].

Vegetative reproduction:  Sprouting from underground or basal portions
is the main form of reproduction of black crowberry [5,20,39].  In
addition, adventitious roots form where procumbent branches come in
contact with the ground [5].


SITE CHARACTERISTICS : 
Black crowberry is found from sea level to alpine zones.  It occurs in a
wide variety of habitats including sphagnum bogs or muskegs, open
tundra, rockfields, conifer forests, coastal bluffs, and exposed sea
cliffs [3,38,47,49].  Black crowberry is tolerant of a wide range of
soil moisture conditions, but is intolerant of prolonged water logging,
and on wet sites it is found in better drained areas [5].  Black
crowberry is adapted to harsh climates and it often inhabits sites
exposed to wind, fog, and salt aerosals.  Site characteristics influence
black crowberry morphology:  on sites with high wind exposure, black
crowberry is branched and prostrate; on wet sites it is sparsely
branched and has long annual growth increments; on dry sites it has
branching shoots and is bushy [5].

Black crowberry is found in sandy to rocky soils, glacial till, and
alluvial deposits [8,42].  Soil pH ranges from 2.5 to 7.7 [5].  Black
crowberry establishes itself on mineral soils and stagnant surfaces that
are nutrient enriched [7] but is also classified as an indicator of
nitrogen-poor soils [22].


SUCCESSIONAL STATUS : 
Black crowberry is a pioneer on sandy blowouts, dry, lichen-covered
depressions on eskers [3], and in avalanche areas [30].  However, it is
more often associated with late seral or climax communities,
particularily white or black spruce types [8,24,45].  Black crowberry is
common and abundant in old forests that have had no recent fires [14].


SEASONAL DEVELOPMENT : 
Flowering occurs in spring in areas of early snowmelt and continues
through July.  Fruits mature from August to late fall and persist
through the winter under snow cover [18,32,42,47].

Related categories for Species: Empetrum nigrum | Black Crowberry