| Climate | Geology and geography
| Flora and fauna | Humans | Images
The Boreal Shield covers a wide swath from Alberta to Newfoundland,
south of the Taiga Shield and Hudson Plains and north of various ecozones,
including the Boreal Plains, Mixedwood Plains, and Atlantic Maritime.
Largest of Canada's ecozones, the Boreal Shield provides the images
of exposed bedrock, endless forests, and rushing rivers that characterize
the image that much of the world (as well as many Canadians) has of
Canada. Summers have roughly the same average temperature throughout
the area, about 13șC. The maritime influence in the east gives it a
milder winter, with a mean temperature of about -1șC, while the western
edge suffers through average winter temperatures of -20șC. Precipitation
in the west is low, about 400mm a year, but it can be a high as 1600mm
a year in some areas of Newfoundland, largely due to its position in
ecozone is named after the intersection of the boreal forest and the
Canadian Shield, and the Precambrian granite bedrock of the latter is
commonly exposed here. This may have once been a soaring mountain range,
judging by its tumultuous geological past, but that was a billion years
ago, and all that is left now is rolling hills. Glaciers swept over
this area many times, and the resulting series of depressions and deposits
have given rise to the millions of lakes and wetlands in the region.
Forest fires create a patchwork of forest types in different stages
of recovery from the fire. Trees to the north are coniferous, but broadleaf
trees appear further south and trees normally found in much warmer climates,
such as the yellow birch and sugar maple, can be found in the south
of the ecozone. Bogs and other wetlands, some of the most diverse and
productive areas in the Boreal Shield, cover one-fifth of the land.
Tree species that can be found here include the white
balsam poplar, white pine, red
pine, jack pine,
eastern white pine,
red maple, mountain
red cedar, eastern
alder, pin cherry,
paper birch and
Some of the other plants that grow here are ericaceous shrubs, sphagnum
moss, willow, alder, Labrador tea, blueberry, bog rosemary, feathermoss,
cottongrass, sedges, kalmia heath, high bush cranberry, baneberry, wild
sarsaparilla, bunchberry, shield fern, goldenrod, water lilies and cattails.
Some of the characteristic
large herbivores of the region include woodland
deer, and moose.
The larger carnivores in the Boreal Shield are the black
Small herbivores and herbivores include raccoon,
hare, red-backed vole, red
bog lemming and arctic
hare. They are in turn preyed upon such smaller carnivores as the
and red fox.
Aquatic mammals found off
of the eastern coast of the ecozone include grey
seal , sperm
pilot whale, fin
right whale, bowhead
Birds of prey in this ecozone include the boreal
horned owl, hawk
vulture, and broad-winged
hawk. The yellow
rumped warbler, blue
sparrow are just a few of the songbirds found here. The forests
hold such species as spruce
grouse, and the pileated
woodpecker. Spring brings large flocks of waterbirds to nest and
breed in the wetlands or just to feed for the rest of their migration
further north. They include the common
black duck, wood duck, Canada
blue heron, ring-necked
duck, and bufflehead.
Shorebirds and seabirds found off the eastern coast include the herring
cormorant, and Atlantic
puffin, along with various murre, eider, tern and pelican species.
Reptiles and Amphibians
Many species of reptiles and amphibians live in the Boreal Shield. Some
of the frogs and toads include the spring
peeper, wood frog,
mink frog, and
northern leopard frog.
redback salamanders, and eastern
newts can be found in moist areas. The common
snapping turtle and painted
turtle are two of the turtle species that live in the ecozone. Two
types of garter snake, the maritime
garter snake and eastern
gartern snake, as well as the redbelly
snake, make their home here.
Predatory fish in the ecozone include the lake sturgeon, brook trout,
lake trout, northern pike, muskellunge, largemouth bass, sauger, and
walleye. Some of the fish that they prey upon include cisco, (lake herring),
blackfin cisco, lake whitefish, rainbow smelt, lake chub, golden shiner,
and yellow perch. Anadramous fish, which live in the ocean but enter
freshwater to spawn, include the silver lamprey, northern brook lamprey,
american brook lamprey, sea lamprey, alewife and Atlantic salmon.
The valve snail,
fingernail clam, and globular
pea clam are just a few of the mollusc species in the Boreal Shield.
Insects are common in the
Boreal Shield; some of the species include the german
turpentine beetle, boreal
cloak, and bush
The extensive waterways in the Boreal Shield were the roads of the fur
trade. More recently, some rivers have been altered and degraded by
mining, hydroelectric development, and logging practices, though many
are still relatively unaffected. Insect control, monoculture tree plantings,
control of natural forest fires and acidification of the lakes and soil
all affect the natural system, but in many cases the long-term effects
are unclear. The current population is approximately three million.