Information AboutTaiga |
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s, just below the Tundra , and just above the Steppe s.]] Taiga ( тайга́) is a Biome characterized by Conifer ous forests. Covering most of inland Alaska , Canada , Sweden , Finland , and northern Russia (especially Siberia ), the taiga is the world's largest terrestrial biome and a major source of Oxygen . In Canada , '''boreal forest''' is the term used to refer to the southern part of this biome, while "taiga" is used to describe the more barren northern areas south of the Arctic Tree-line . Since North America and Eurasia were recently connected by the Bering Land Bridge , a number of animal and plant species (more animals than plants) were able to colonise both continents and are distributed throughout the taiga biome. Others differ regionally, typically with each genus having several distinct species, each occupying different regions of the taiga. CLIMATE AND GEOGRAPHY The taiga biome has a harsh continental climate with a very large temperature range between summer and winter, classified as "Dfc" or "Dfb" in the Köppen Climate Classification scheme. Aside from the Tundra and permanent ice caps, it is the coldest biome on Earth. High latitudes mean that, for much of the year the Sun hovers at the horizon; winters last at least 6 months, with average temperatures below freezing. Temperatures vary from -50 ˚C to 30 ˚C throughout the whole year, with 8 or more months of temperatures averaging below 10 ˚C. The summers, while short, are generally warm and humid. The taiga experiences relatively low Precipitation throughout the year (200-750 mm annually), primarily as rain during the summer months, but also as fog and snow; as evaporation is also low for most of the year, precipitation exceeds evaporation and is sufficient for dense vegetation growth. Much of the area currently classified as taiga was Recently Glaciated . As the glaciers receded, they gouged out depressions in the topography. These depressions have since filled with water, creating lakes and bogs (especially Muskeg soil), found throughout the taiga. FLORA The forests of the taiga are largely Coniferous , dominated by Larch , Spruce , and Pine . Evergreen species in the taiga (spruce and pine) have a number of adaptations specifically for survival in harsh taiga winters, though larch, the most cold-tolerant of all trees, is Deciduous . Because the sun is low in the horizon for most of the year, it is difficult for plants to generate energy from Photosynthesis . Pine and spruce do not lose their leaves seasonally and are able to photosynthesize with their older leaves in late winter and spring when light is good but temperatures are still too low for new growth to commence. The adaptation of evergreen needles limits the water lost due to Transpiration and their dark green color increases their absorption of sunlight. Although precipitation is not a limiting factor, the ground freezes during the winter months and plant roots are unable to absorb water, so desiccation can be a severe problem in late winter for evergreens. Although the taiga is dominated by coniferous forests, some Broadleaf Trees also occur, notably Birch , Aspen , Willow , and Rowan . Many smaller Herbaceous plants grow closer to the ground. Periodic stand-replacing Wildfire s (with return times of between 20-200 years) clear out the tree canopies, allowing sunlight to invigorate new growth on the forest floor. For some species, wildfires are a necessary part of the life cycle in the taiga; some, e.g. Jack Pine have cones which only open to release their seed after a fire, dispersing their seeds onto the newly cleared ground. Grass es grow wherever they can find a patch of sun, and Moss es and Lichen s thrive on the damp ground and on the sides of tree trunks. In comparison with other biomes, however, the taiga has a low biological diversity. FAUNA The taiga is home to a number of large Herbivorous Mammal s and smaller Rodent s. These animals have also adapted to survive the harsh climate. Many of the larger mammals, such as Black Bear s, eat during the summer in order to gain weight and then go into Hibernation during the winter. Other animals have adapted layers of fur or feathers to insulate them from the cold. Due to the climate, Carnivorous diets are an inefficient means of obtaining energy; energy is limited, and most energy is lost between Trophic Level s. However, Predator y birds ( Owl s and Eagle s) and other smaller carnivores, including Fox es and Weasel s, feed on the rodents. Larger carnivores, such as Lynx es and Wolves , prey on the larger animals. Omnivore s, such as Bear s and Raccoon s are fairly common, sometimes picking through human garbage. A considerable number of Bird s such as Siberian Thrush , White's Thrush and Dark-throated Thrush , Migrate to this Habitat to take advantage of the long summer days and abundance of Insect s found around the numerous bogs and lakes. Some seed-eating birds and Carrion (or large Omnivorous birds that can take live prey) live in the taiga throughout winter. They include Crossbill , Golden Eagle , Raven and Rough-legged Buzzard . SEE ALSO EXTERNAL LINKS
Cold Climate Forest. ThinkQuest. Oracle. {Link without Title} .
The Evergreen Coniferous Forest. World Builders (1998). California State University. 11 Dec 2005. {Link without Title} .
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