text: 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.
  Climate
  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 13ºC. The maritime influence in the east gives it a milder winter, with a mean temperature of about -1ºC, while the western edge suffers through average winter temperatures of -20ºC. 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 the Atlantic.
  Geology and Geography
  This 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.
  Flora and Fauna
  Plants
  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 spruce, black spruce, balsam fir, tamarack, trembling aspen, balsam poplar, white pine, red pine, jack pine, eastern white pine, red maple, mountain maple, eastern red cedar, eastern hemlock, black ash, speckled alder, pin cherry, paper birch and white birch. 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.
  Animals
  Mammals
  Some of the characteristic large herbivores of the region include woodland caribou, barren-ground caribou, white-tailed deer, and moose. The larger carnivores in the Boreal Shield are the black bear, lynx, bobcat, and wolf. Small herbivores and herbivores include raccoon, striped skunk, eastern chipmunk, beaver, muskrat, showshoe hare, red-backed vole, red squirrel, least chipmunk, porcupine, woodchuck, southern bog lemming and arctic hare. They are in turn preyed upon such smaller carnivores as the marten, short-tailed weasel, fisher, ermine, mink, river otter, coyote, and red fox.
  Aquatic mammals found off of the eastern coast of the ecozone include grey seal, harp seal, hooded seal, ringed seal , sperm whale, orca, Atlantic pilot whale, fin whale, blue whale, northern right whale, bowhead whale,and humpback whale.
  Birds
  Birds of prey in this ecozone include the boreal owl, great horned owl, hawk owl, bald eagle, red-tailed hawk, turkey vulture, and broad-winged hawk. The yellow rumped warbler, blue jay, evening grosbeak, gray jay, common nighthawk, raven, mourning dove, cardinal, wood thrush, rock ptarmigen, willow ptarmigan and white-throated sparrow are just a few of the songbirds found here. The forests hold such species as spruce grouse, ruffed grouse, sharp-tailed 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 loon, sandhill cranes, hooded merganser, American black duck, wood duck, Canada goose, great blue heron, ring-necked duck, and bufflehead. Shorebirds and seabirds found off the eastern coast include the herring gull, double-crested 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. Yellow-spotted salamanders, blue-spotted salamanders, eastern 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 common gartern snake, as well as the redbelly snake, make their home here.
  Fish
  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.
  Molluscs
  The valve snail, ordinary spire snail, eastern elliptio, arctic-alpine fingernail clam, and globular pea clam are just a few of the mollusc species in the Boreal Shield.
  Insects
  Insects are common in the Boreal Shield; some of the species include the German cockroach, red turpentine beetle, boreal spittlebug, spring azure, American copper, monarch butterfly, mourning cloak, and bush katydid.
  Humans
  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.