(DRAFT) - Taxonomy
Species caribou
Species Id M050030
Date 26 AUG 96
TAXONOMY
NAME - caribou
OTHER COMMON NAMES -
ELEMENT CODE -
CATEGORY - Mammals
PHYLUM AND SUBPHYLUM - ,
CLASS AND SUBCLASS - ,
ORDER AND SUBORDER - ,
FAMILY AND SUBFAMILY - ,
GENUS AND SUBGENUS - Rangifer,
SPECIES AND SSP - tarandus, granti
SCIENTIFIC NAME - Rangifer tarandus granti
AUTHORITY - Banfield, 1961
TAXONOMY REFERENCES - 232
Taxonomy - 1 (DRAFT) - Status
Species caribou
Species Id M050030
Date 26 AUG 96
STATUS
Coded Status
Migrant
See Comments
REFERENCES FOR STATUS - 232
COMMENTS ON STATUS -
The Alaska Department of Fish and Game has regulatory authority over caribou
*232*.
The caribou migrate in Alaska, primarily seasonally migrations *232*.
Status - 1 (DRAFT) - Distribution
Species caribou
Species Id M050030
Date 26 AUG 96
DISTRIBUTION
Distribution - 1 HABITAT ASSOCIATIONS
HABITAT - TERRESTRIAL
REFERENCES FOR HABITAT - 232
LAND USE -
Water
Streams and Canals
Lakes
Shrub and Brush Rangeland
Barren Land
Beaches
Sandy Areas other than Beaches
Bare Exposed Rock
Snow or Ice: Glaciers
Evergreen Forest Land
Tundra Land: Herbaceous
Wetland
REFERENCES FOR LAND USE - 232
COMMENTS ON HABITAT ASSOCIATIONS -
Caribou feed on aquatic vegetation found along lake margins and streams.
The use of ridge tops, frozen lakes, gravel bars, and elevated terrain
to avoid insects. Also used are arctic coastal areas (sand dunes, beaches,
river deltas, and points of land) *232*.
Depending on the availability and location of habitat, spruce forests
(primarily spruce/lichen associations), bogs, and lake shores are used
extensively. On the Alaska Peninsula's poorly drained coastal plains, areas
where sedges are abundant are used. Ridge tops and high plateaus are also
important *232*.
Open terrain with gentle slopes and shallow U-shaped valleys are used.
Vegetation falls primarily into grass meadow, shrub birch, dwarf heath
types, and sedge meadows *232*.
Areas of use consist primarily of treeless uplands where heath tundra,
alpine tundra, and sedge wetland associations dominate. In response to
insect harassment, caribou frequently use wind-swept ridges and coastal
areas *232*.
ANIMAL/PLANT SPECIES ASSOCIATIONS -
Wolf
Bear
REFERENCES FOR SPECIES ASSOCIATIONS - 232
COMMENTS ON SPECIES ASSOCIATIONS -
Wolf and bear predation, in some areas, can be an important factor in
population regulation *232*.
POTENTIAL NATURAL VEGETATION -
099 Northern Hardwoods - Spruce Forest (Acer-Betula-Fagus
REFERENCES FOR PNV - 232
Habitat Associations - 1 (DRAFT) - Food Habits
Species caribou
Species Id M050030
Date 26 AUG 96
FOOD HABITS
TROPHIC LEVEL -
HERBIVORE/BROWSER
HERBIVORE/GRAZER
REFERENCES FOR TROPHIC LEVEL - 232
LIFESTAGE FOOD FOOD PART
General Lichens Not Specified
General Cyperaceae Not Specified
General Poaceae Not Specified
General Salicaceae Not Specified
General Sphenopsida Not Specified
General Ericaceae Not Specified
General Salicaceae Buds
General Betulaceae Not Specified
General Salicaceae Leaves/Needles
General Leguminosae Not Specified
General Zygophyllaceae Not Specified
General Cyperaceae Leaves/Needles
General Cyperaceae Bole/Stem
General Poaceae Leaves/Needles
General Poaceae Bole/Stem
General Salicaceae Bole/Stem
General Salicaceae Buds
General Salicaceae Leaves/Needles
General Betulaceae Leaves/Needles
General See Comments; Food See Comments
REFERENCES FOR GENERAL FOOD - 232
COMMENTS ON FOOD -
Winter (mid October to mid April): Fruticose lichens (Cladonia spp. and
Cetraria spp.), sedges, and grasses are heavily utilized. Willow,
horsetails, and dwarf shrubs (e.g., Vaccinium uliginosum) may be used to
some extent. Although these plants may be used less by caribou during
winter, they may be nutritionally significant *232*.
Spring (mid April to mid June): The catkins of willow (especially Salix
alaxensis, S. planifolia spp. pulchra, and S. glauca) are among the first of
the new-growth vegetation to be eaten. Various grasses and sedges (notably
Carex bigelowii, C. membranacea, C. podocarpa, and Eriophorum vaginatum) are
also used extensively. Fruticose lichens continue to be eaten during spring
if available and especially if the growing season is late. Resin birch
(Betula glandulosa), dwarf birch (B. nana), and especially willow leaves
become the favored foods as the season progresses, as do horsetails, which
are especially attractive *232*.
Summer (mid June to mid August): Caribou continue to eat the leaves of
willow, resin birch, and dwarf birch extensively during June and July. Many
species of sedge and grass (especially those of the genera Alopecurus,
Food Habits - 1 (DRAFT) - Food Habits
Species caribou
Species Id M050030
Date 26 AUG 96
Arctagrostis, Dupontia, Festuca, Poa, Puccinellia, Calamagrostis, and
Hierochloe), forbs, and horsetails are used extensively, depending upon
their growth stage, annual differences in weather, and the particular area
being used by the caribou. Legumes are especially important; species of
particular note include Astragalus umbellatus, Lupinus arcticus, Hedysarum
alpinum, and Oxytropis nigrescens. The herbs Gentiana glauca, Swertia
perennis, and Sedum roseum are highly palatable. Other species known to be
grazed include Antennaria monocephala, Artemisia arctica, Epilobium
latifolia, Pedicularis spp., Petasites frigidus, Polygonum bistorta, Rumex
arcticus, and Saxifraga spp. *232*
Fall (mid August to mid October): During the fall, the quality and
palatability of the summer forage decrease, and the caribou's diet gradually
shifts toward the more restrictive winter forage. Willow leaves are heavily
utilized as long as they are available. Grasses and sedges are eaten
throughout the fall period. Lichens are increasingly used as the fall
progresses. Carex aquatilis, which lines the shores of lakes, ponds, and
sloughs, appears to be an especially favored food item *232*.
Types of Feeding Areas Used:
Winter: Depending on the availability and location of habitat, spruce
forests (primarily spruce/lichen associations), bogs, and lake shores
are used extensively. On the Alaska Peninsula's poorly drained coastal
plains, areas where sedges are abundant are used. Ridge tops and high
plateaus are also important *232*.
Spring: Open terrain with gentle slopes and shallow U-shaped valleys
are used. Vegetation falls primarily into grass meadow, shrub birch,
dwarf heath types, and sedge meadows *232*.
Summer: Areas of use consist primarily of treeless uplands where heath
tundra, alpine tundra, and sedge wetland associations dominate. In
response to insect harassment, caribou frequently use wind-swept ridges
and coastal areas *232*.
Fall: Caribou remain on or near summer ranges until the quantity and
quality of forage significantly decreases and/or weather forces them to
begin migration toward the wintering grounds. Because fall migration
generally occurs during this period and feeding often occurs on the
move, it is difficult to relate specific feeding locations to this
period *232*.
Factors Limiting Availability of Food:
Winter: Snow depth of 50 cm (20 inches) is generally considered the
upper limit for use of areas by caribou. Ice crust of 4 to 6.5 cm
(1.5-2.5 inches) on top of the snow is considered the upper limit
caribou can paw through to obtain food *232*.
Spring: Calving area selections by caribou have been, in part,
attributed to early snowmelt and the consequent availability of new
vegetation. Should a late snowmelt or a late snowstrom occur, use of
Food Habits - 2 (DRAFT) - Food Habits
Species caribou
Species Id M050030
Date 26 AUG 96
otherwise preferred early green-up vegetation may be restricted *232*.
Summer: Insect harassment can restrict caribou feeding by causing them
to move about constantly or occupy areas such as snowdrifts, where food
is unavailable. In the arctic, coastal beaches, river deltas, and sand
dunes are heavily used for relief from insect harassment *232*.
Fall: Increasing frost and/or snow in the high country decrease the
quantity and quality of forage, in part triggering fall migration *232*.
Feeding Behavior:
Winter and Fall: Feeding generally occurs during the mid portions of
the day and night. Caribou prefer the finer parts of plants, such as
the upper portions of lichens, leaves and stem tips of sedges and
grasses, and the stem tips and buds of willows. Their cursory grazing
habits help reduce the possibility of overgrazing the range *232*.
Spring: Feeding behavior is similar to winter, with an increased use of
leaves of willow and dwarf birch *232*.
Summer: Caribou select plant species according to the occurrence of
greening leaf and flower buds. Feeding occurs throughout the day, but
because of insect harassment most feeding takes place during the cooler
twilight hours *232*.
Food Habits - 3 (DRAFT) - Environment Associations
Species caribou
Species Id M050030
Date 26 AUG 96
ENVIRONMENTAL ASSOCIATIONS
G = General A = Adult
LIM = Limiting RA = Resting Adult
J = Juvenile FA = Feeding Adult
RJ = Resting Juvenile BA = Breeding Adult
FJ = Feeding Juvenile P = Pupae
L = Larvae E = Egg
RL = Resting Larvae
FL = Feeding Larvae
LIFESTAGE ENVIRONMENTAL ASSOCIATIONS
G Inland Wetlands: Bogs
G Inland Wetlands: Specified in Comments
G Terrestrial Features: Ridges
G Terrestrial Features: Specified in Comments
RA Terrestrial Features: Ridges
RA Terrestrial Features: Specified in Comments
G Inland Wetlands: Bogs
G Inland Wetlands: Specified in Comments
RA Inland Wetlands: Bogs
RA Inland Wetlands: Specified in Comments
BA Slope: Specified in Comments
G Soil Needs: Gravel
G Soil Needs: Specified in Comments
G Elevation: Specified in Comments
G Coastal Features: Specified in Comments
G Coastal Features: Dunes
G Coastal Features: Sand beaches
FA Coniferous Forest: Specified in Comments
FA Inland Wetlands: Bogs
FA Inland Wetlands: Specified in Comments
FA Terrestrial Features: Ridges
FA Terrestrial Features: Specified in Comments
FA Slope: Specified in Comments
FA Terrestrial Features: Specified in Comments
FA Meadows: Specified in Comments
FA Elevation: Specified in Comments
FA Inland Wetlands: Specified in Comments
FA Coastal Features: Specified in Comments
BA Elevation: Specified in Comments
G Aspect: Northwest
G Slope: Specified in Comments
G Aspect: Specified in Comments
G Aquatic Vegetation [specified type]: Specified in comments
FA Hardwood Forest: Willow
FA Hardwood Forest: Specified in Comments
BA Aspect: South
BA Aspect: Specified in Comments
REFERENCES FOR ENVIRONMENTAL ASSOC_ - 232
Environment Associations - 1 (DRAFT) - Environment Associations
Species caribou
Species Id M050030
Date 26 AUG 96
REFERENCES FOR FEEDING ADULT ENVIRONMENTAL ASSOC_ - 232
REFERENCES FOR RESTING ADULT ENVIRONMENTAL ASSOC_ - 232
REFERENCES FOR BREEDING ADULT ENVIRONMENTAL ASSOC_ - 232
COMMENTS ON ENVIRONMENTAL ASSOCIATIONS -
Aquatic: During summer, except for the arctic herds, which avoid marshy
areas during mosquito season, caribou tend to concentrate their feeding
activity in moist boggy areas where sedges (Carex spp.) predominate.
Riparian areas are also important during mid summer. During winter, aquatic
vegetation, such as sedges and horsetails (Equisetum spp.), are heavily
used along lake margins and streams. Muskrat pushups, which consist of a
variety of aquatic vegetaion, are frequented by wintering caribou, but the
total food content is neglible *232*.
Terrestrial Cover Requirements: The use of ridge tops, frozen lakes and
bogs, and other open areas for resting may be learned behavior related to
predator avoidance that may have resulted from wolf-caribou interactions.
The caribou's apparent reluctance to enter riparian willow (Salix spp.)
stands and other heavy brush cover and its state of alertness when passing
through such areas suggest that caribou associate such cover with attacks
by wolves and bears. On the arctic coastal plain, where riparian stands
are sparse, caribou do not show any apparent avoidance behavior of heavy
brush cover types. During the spring calving period, caribou tend to
occupy open terrain with gentle slopes affording a wide field of view,
which again may be related to predator avoidance. Calving areas are also
characterized by their close proximity to insect relief habitat and are
usually well drained. During summer, caribou make extensive use of
windswept ridges, lingering snow drifts, glaciers, gravel bars, and
elevated terrain to avoid insects. Arctic coastal areas (sand dunes,
beaches, river deltas, and points of land) are used as insect relief
habitat *232*.
The Mentasta Herd ranges along the northwest slopes of the Wrangell
Mountains and the headwaters of the Copper River *232*.
COMMENTS ON RESTING ADULT ENVIRONMENTAL ASSOC_ -
The use of ridge tops, frozen lakes and bogs, and other open areas for
resting may be learned behavior related to predator avoidance that may have
resulted from wolf-caribou interactions *232*.
COMMENTS ON FEEDING ADULT ENVIRONTAL ASSOC_ -
Types of Feeding Areas Used:
Winter: Depending on the availability and location of habitat, spruce
forests (primarily spruce/lichen associations), bogs, and lake shores
are used extensively. On the Alaska Peninsula's poorly drained coastal
plains, areas where sedges are abundant are used. Ridge tops and high
plateaus are also important *232*.
Spring: Open terrain with gentle slopes and shallow U-shaped valleys
are used. Vegetation falls primarily into grass meadow, shrub birch,
Environment Associations - 2 (DRAFT) - Environment Associations
Species caribou
Species Id M050030
Date 26 AUG 96
dwarf heath types, and sedge meadows *232*.
Summer: Areas of use consist primarily of treeless uplands where heath
tundra, alpine tundra, and sedge wetland associations dominate. In
response to insect harassment, caribou frequently use wind-swept ridges
and coastal areas *232*.
Fall: Caribou remain on or near summer ranges until the quantity and
quality of forage significantly decreases and/or weather forces them to
begin migration toward the wintering grounds. Because fall migration
generally occurs during this period and feeding often occurs on the
move, it is difficult to relate specific feeding locations to this
period *232*.
COMMENTS ON BREEDING ADULT ENVIRONMENTAL ASSOC_ -
During the spring calving period, caribou tend to occupy open terrain with
gentle slopes affording a wide field of view, which again may be related to
predator avoidance. Calving areas are also characterized by their close
proximity to insect relief habitat and are usually well drained *232*.
Reproductive Habitat: The rut usually takes place during fall migration and
is sometimes accompanied by a pause or slowdown of movement. Breeding
usually takes place in areas above timberline, although this has not been
the case during most recent years of the Nelchina Herd *232*.
Caribou in Spatsizi Provincal Park, British Columbia, dispersed to high
south slopes in mountains for calving as an antipredator tactic *232*.
Environment Associations - 3 (DRAFT) - Life History
Species caribou
Species Id M050030
Date 26 AUG 96
LIFE HISTORY
REPRODUCTIVE CHARACTERISTICS
Reproductive Habitat: The rut usually takes place during fall migration and
is sometimes accompanied by a pause or slowdown of movement. Breeding
usually takes place in areas above timberline, although this has not been
the case during most recent years of the Nelchina Herd *232*.
Reproductive Seasonality: Breeding seasonality varies in different parts of
the caribou range. In central and southern Alaska, caribou breeding occurs
primarily during the first two weeks of October. In southwestern and
southcentral Alaska, parturition generally occurs from early May through the
first week of June. For the arctic herds, calving begins in late May, peaks
around the end of the first week of June, and is completed by mid June
*232*.
Reproductive Behavior: Bulls do not gather harems but rather join existing
bands of cows and young. Bulls tend to become dominant within bands,
depending on the size of the group. As the rut peaks, dominant bulls reduce
their foraging markedly, concentrating instead on tending estrous females.
Copulation is brief and generally occurs at dawn or dusk. By the end of the
rut, breeding adult bulls have depleted their fat reserves and enter winter
in lean condition. Cows do not actively seek isolation to give birth.
Caribou in Spatsizi Provincal Park, British Columbia, dispersed to high
south slopes in mountains for calving as an antipredator tactic. The
mother-young bond is initiated within the first minutes of the calf's life
and is necessary for the survival of offspring during the first six months
of life. After calves are mobile, "nursery bands" of cows and calves are
formed. In central Alaska, most cows do not regroup or join mobile bands
until their calves are older than two days *232*.
Age at Sexual Maturity: Most cows conceive at 2.5 years of age. A few will
conceive at 1.5 years, however, if in good condition. Bulls are sexually
mature at 1.3 to 2.3 years of age *232*.
Fecundity: Adult females (3+ years) have pregnancy rates of about 80 % and
produce one offspring per year *232*.
Gestation Period: Gestation takes 225 to 235 days *232*.
Lactation Period: Little is known about the actual weaning process. Weaning
must occur during July because biting insects would greatly disrupt nursing
after July. A study suggested weaning takes place between September and
December and mostly occurs prior to November. However, empirical evidence
exists indicating most cows still lactate in August and September, with some
individuals lasting into October *232*.
FACTORS INFLUENCING POPULATIONS
Natural: Emigration, which may be density-related, can cause large
fluctuations in herd sizes; however, this phenomenon has never been
documented. Weather, particularly precipitation, cold, and wind, are a
Life History - 1 (DRAFT) - Life History
Species caribou
Species Id M050030
Date 26 AUG 96
deadly combination for newborn calves, often resulting in hypothermia. Wolf
and bear predation, in some areas, can be an important factor in population
regulation. Fire has changed successional stages in large expanses of
winter range but in fact may not have caused major fluctuations in
population numbers. It is possible, however, that fire has caused shifts in
habitat use by caribou herds *232*.
Human-related: A summary of possible impacts from human-related activities
includes the following: competition with introduced (wild or domestic)
animals; increased susceptibility to predation; alteration of habitat;
harassment, active and passive; barriers to movement, physical and
psychological; overharvest, especially when associated with high predation
rates; direct mortality associated with collisions with trains and cars; and
vegetation damage/destruction due to air pollution *232*.
Food supply, population density, weather, snow conditions, insects, man, and
a variety of other factors can alter caribou movement patterns seasonally
and perhaps for several years *232*.
FEEDING BEHAVIOR
Winter and Fall: Feeding generally occurs during the mid portions of the day
and night. Caribou prefer the finer parts of plants, such as the upper
portions of lichens, leaves and stem tips of sedges and grasses, and the
stem tips and buds of willows. Their cursory grazing habits help reduce the
possibility of overgrazing the range *232*.
Spring: Feeding behavior is similar to winter, with an increased use of
leaves of willow and dwarf birch *232*.
Summer: Caribou select plant species according to the occurrence of greening
leaf and flower buds. Feeding occurs throughout the day, but because of
insect harassment most feeding takes place during the cooler twilight hours
*232*.
LIFE HISTORY CODES -
Periodicity: Other (specify in comments)
Periodicity: Most active in fall
Breeding/Spawning Season: October
Breeding/Spawning Season: May
Breeding/Spawning Season: June
Breeding/Spawning Season: July
Periodicity: Active at dawn and/or dusk (crepuscular)
Parental Care of Young: Female
Average Number of Offspring/Reproductive Effort: 1
Gestation/Incubation Period: 7-8 months
Dispersion: Clumped
Foraging Strategy: Grazing
Foraging Strategy: Browsing
REFERENCES FOR LIFE HISTORY- 232
Life History - 2 (DRAFT) - Management Practices
Species caribou
Species Id M050030
Date 26 AUG 96
MANAGEMENT PRACTICES
RESULT MANAGEMENT PRACTICE
Beneficial Controlling undesirable vertebrate species
Beneficial Developing/maintaining habitat diversity
Beneficial Restricting/regulating human disturbance of populations
Adverse Migration barriers
Beneficial Regulating harvest of species being described
Beneficial Restricting/regulating human use of habitats
Beneficial Controlling pollution [thermal, chemical, physical]
Beneficial Other management practices [specified in comments]
Adverse Other management practices [specified in comments]
REFERENCES FOR BENEFICIAL MANAGEMENT PRACTICES - 232
REFERENCES FOR ADVERSE MANAGEMENT PRACTICES - 232
COMMENTS ON MANAGEMENT PRACTICES -
FACTORS INFLUENCING POPULATIONS
Natural: Emigration, which may be density-related, can cause large
fluctuations in herd sizes; however, this phenomenon has never been
documented. Weather, particularly precipitation, cold, and wind, are a
deadly combination for newborn calves, often resulting in hypothermia. Wolf
and bear predation, in some areas, can be an important factor in population
regulation. Fire has changed successional stages in large expanses of
winter range but in fact may not have caused major fluctuations in
population numbers. It is possible, however, that fire has caused shifts in
habitat use by caribou herds *232*.
Human-related: A summary of possible impacts from human-related activities
includes the following: competition with introduced (wild or domestic)
animals; increased susceptibility to predation; alteration of habitat;
harassment, active and passive; barriers to movement, physical and
psychological; overharvest, especially when associated with high predation
rates; direct mortality associated with collisions with trains and cars; and
vegetation damage/destruction due to air pollution *232*.
Management Practices - 1 (DRAFT) - References
Species caribou
Species Id M050030
Date 26 AUG 96
References
232 * State of Alaska Department of Fish, and Game. 1986. Alaska
Habitat Management Guide: Life Histories and Habitat
Requirements of Fish and Wildlife. (ed.). Alaska Department of
Fish and Game Juneau, Alaska:763.
References - 1