All About Water

The Taiga Ecosystem

The taiga, or boreal forest, is an ecosystem found across the northern regions of North America and Eurasia. It covers much of Canada and extends down into the northwestern United States. In Europe, Scandinavia and much of Russia is covered with boreal forest. Large cities including Moscow and Toronto are found in the southernmost part of the taiga, but farther north it is mostly unpopulated by humans. The taiga is composed of coniferous trees in an almost continuous belt. Boreal forest grows over areas that were once covered by glaciers and still retain some patchy areas of permafrost. Winter in the taiga is long and harsh, with temperatures dipping as low as -90 degrees Fahrenheit. The winter can last up to six months. The summer season is brief, comprising only about fifty to one hundred frost-free days. The taiga has little annual precipitation, only about fifteen to twenty inches, but its climate is humid because of low evaporation.

Plant Life in the Taiga

Taiga woodland soil is rocky, acidic and low in nutrients. The primary vegetation in the boreal forest is coniferous, needle-leaf trees. In North America, the dominant species of coniferous trees are fir and spruce. In Scandinavia and throughout Russia, the Scots pine is usually dominant. Deciduous trees and shrubs are also common, including alder, birch and aspen.

Coniferous forest is well adapted to difficult growing conditions. Needles remain green year-round, which means that the trees don’t need to expend energy by growing new leaves every year. The needles also limit water loss through transpiration, allowing evergreen trees to stay alive even when the ground is frozen and water from the soil is difficult to come by. The shape of the branches allows snow to slide off rather than build up and cause the branches to break.

Animal Life in the Taiga

The boreal forest is home to a wide variety of animal life, including predatory mammals like lynxes, bobcats, bears, and weasels; small herbivores like snowshoe hares, lemmings, and voles; and large herbivores like elk and moose.

Many birds in the taiga, such as wood warblers, are migratory and leave after the warmer season. Seed-eating birds like finches and omnivores like ravens make their home in the tundra year-round. Animals that live year-round in the taiga must adapt. Some hibernate through the coldest part of the season. Others produce an extra layer of fur or feathers to help them survive. Some animals change color to help them blend in with their snowy surroundings.

Water Pollution in the Taiga

Long ago, the taiga was covered by glaciers. When they receded, they left huge gouges and depressions. When it rains, the depressions fill, and lakes and bogs form. The bogs and ponds are a great breeding ground for insects, which help support the migratory bird populations.

Some areas of the taiga are at risk of deforestation caused by acid rain. Russia has a number of plants which smelt nickel, aluminum and lead. These plants emit chemicals into the atmosphere, which causes acid rain to form. Some rivers in the taiga are also at risk, due to the damage caused by the timber industry. Logs sink and cause flooding. When areas of the forest are cut clear, the topsoil erodes into the rivers and streams.

For more information on water and biomes, check out Role of Water in Ecosystems and Biomes

• Extreme cold
• Simple structure of vegetation
• Short growth and reproduction seasons
• Dead organic materials provide most of the energy and nutrients in the system
• Large oscillations in the population

Climate of the Tundra

The growing season lasts for a meager 50 to 60 days in Arctic tundra, and about 180 days for Alpine tundra. The average temperature in winter is -30 degrees Fahrenheit. In the brief summer, the temperature averages 37 to 54 degrees. A layer of permafrost, or permanently frozen soil, is always present, although it’s depth is variable. Bogs and ponds form in the Arctic tundra in the summer when the permafrost melts slightly and precipitation floods the area. These bogs provide moisture for the plant life that is acclimated to the environment. Alpine tundra soil has better drainage.

Plant Life in the Tundra

The plant life that exists is simple, but of surprising diversity. The tundra is able to support:

• Reindeer moss
• Low shrubs
• Sedges and grasses
• Lichen
• About 400 different types of flowering plants

In addition to these plants, Alpine tundra supports:

• Tussock grasses
• Dwarf pines
• Heaths

The plants found in the tundra are short and grow close to the ground. They are adapted to the harsh cold.

Animal Life in the Tundra

Like plant life, the animal life is also diverse. Herbivorous mammals like voles, caribou and arctic squirrels call the Arctic tundra their home, as do the carnivorous mammals that feed on them such as arctic foxes and polar bears. Migratory birds like ravens, falcons and terns can survive here. The cold waters are filled with fish like cod, salmon and trout. Alpine tundra supports pikas, mountain goats and elk, grouse-like birds, and insects such as beetles, grasshoppers and butterflies.

Water Pollution in the Tundra

Because the arctic and alpine ecosystems are so fragile, anything the pollutes the water that the system depends on creates a grave threat to the entire system. A growing concern in the arctic tundra is the threat of oil spills, which float in the water and suffocate plant and animal life. Acid rain is an ongoing concern in the Alpine tundra ecosystem. Many mountain lakes are being rendered sterile, as they do not have much of a buffering capacity.