Tundra Biome: Features, Types, Ecosystem
The word Tundra is derived of a Finnish word “tunturi” which means treeless mountain tract. In Tundra Biome, the tree growth is hindered by low temperatures and short growing seasons. The vegetation in Tundra is composed of Dwarf Shrubs, mosses, lichens etc. Some scattered trees are also found. The ecological boundary (ecotone) between the tundra and taiga forests is called tree line or timberline.
Distribution of Tundra Biome
There are three types of Tundra Regions in the world viz. Arctic Tundra, Alpine Tundra and Antarctic Tundra. In Northern hemisphere, the Tundra occurs north of the Taiga belt.
Salient Features of Tundra Biome
The most important characteristic of Tundra is the Permafrost. Permafrost is the permanently frozen soil. Permafrost is consisting mostly of gravel and finer material. The soil is frozen from 25-90 cms down and very few plants can grow in it, so the permafrost is plain without many trees. Some parts of the permafrost are bare and support growth of some lichens.
- There are ONLY two seasons in Polar Tundra regions viz. summer and winter. During winter, it is very cold and dark, while during summer, the temperature rises a bit and the permafrost melts at some points, making the ground soggy.
- The Arctic Tundra is known for its cold, desert-like conditions. In winter the temperature of Arctic Tundra regions may drop as down as -50°C. The average winter temperature is -34° C (-30° F), but the average summer temperature is 3-12° C (37-54° F) which enables this biome to sustain life. Rainfall may vary in different regions of the arctic. Annual precipitation, including melting snow, is 15 to 25 cm.
- In summer, the upper layer of Permafrost gets melted and when water saturates the upper surface, bogs and ponds may form, providing moisture for plants. There are no deep root systems in the vegetation of the arctic tundra; however, there are still a wide variety of plants that are able to resist the cold climate. There are about 1,700 kinds of plants in the arctic and subarctic, and these include low shrubs, sedges, reindeer mosses, liverworts, and grasses, more than 400 varieties of flowers and crustose and foliose lichen.
- The plants of the Arctic Tundra region are adapted to sweeping winds and disturbances of the soil. Plants are short and group together to resist the cold temperatures and are protected by the snow during the winter. They can carry out photosynthesis at low temperatures and low light intensities. The growing seasons are short and most plants reproduce by budding and division rather than sexually by flowering.
- The fauna in the arctic is also diverse. They include herbivorous mammals such as lemmings, voles, caribou, arctic hares and squirrels, Carnivorous mammals such as arctic foxes, wolves, and polar bears, Migratory birds such as ravens, snow buntings, falcons, loons, sandpipers, terns, snow birds, and various species of gulls, Insects such as mosquitoes, flies, moths, grasshoppers, black flies and arctic bumble bees and Fishes such as cod, flatfish, salmon, and trout.
- The animals of the Arctic Tundra are adapted to handle long, cold winters and to breed and raise young quickly in the summer. Animals such as mammals and birds also have additional insulation from fat. Many animals hibernate during the winter because food is not abundant. Another alternative is to migrate south in the winter, like birds do. Reptiles and amphibians are few or absent because of the extremely cold temperatures. Because of constant immigration and emigration, the population continually oscillates.
Fragile Ecosystem of the Arctic Tundra
From the above description, it is quite clear that the ecosystem of Arctic Tundra is extremely fragile because of the lack of abundant plant life so if the primary consumers can’t find enough food, the predators can’t eat.
In the Arctic Ecosystem, the primary producers, or the plants are on the bottom of the pyramid. These are very limited resources, which are thrown off by the slightest lack of sunlight and water available to them. The permafrost in the ground also throws off the drainage of the water leaving the plants there hard to digest. In the middle are the primary consumers such as lemmings, musk oxen and insects who feed on the limited plant life available. On top are the small predators such as the snowy owl and arctic fox and polar bears. Due the scarcity of the primary producers, the fragile ecosystem and food chain causes the population continually oscillate. This means that extinction of just one species has the capability to destroy the entire ecosystem in Tundra regions.
Global Warming & Tundra Climate
Due to global warming, the future of the tundra becomes more uncertain. The global warming has caused spread of more woody plants by the increasing temperatures, and it has been feared that it may endanger moss and lichen species in two fifths of the biome in the years to come.
Oil Drilling in Tundra
Oil Drilling is popular in the tundra because it is rich in mineral resources. The pollution caused by Oil drilling would kill the habitats of fish, and animals. The major problem of oil drilling is the risk of oil spills. When a large spill occurs, it can kill many tiny organisms when it comes in contact with it. As a result, plants will die and will not be able to produce oxygen that we need to live. Also, the herbivores in the ecosystem will die because they will have no food to eat. This can cause major damage to the food chain.
While the Arctic Tundra is located in Polar regions, the Alpine tundra is located on mountains throughout the world at high altitude where trees cannot grow. Alps and Pyrenees of Europe, the Rift Mountains of Africa (such as Mount Kilimanjaro), and a large portion of the Tibetan Plateau are best examples of Alpine Tundra. The growing season is approximately 180 days. The night-time temperature is usually below freezing.
Difference between Arctic Tundra and Alpine Tundra
The major difference between the arctic Tundra and Alpine Tundra is that unlike the arctic tundra, the soil in the alpine is well drained. The Alpine Tundra does not have permafrost. The plants of Alpine Tundra are very similar to those of the arctic ones, however there is a major difference in the fauna of Arctic Tundra and Alpine Tundra. Kea parrot, marmot, mountain goats, chinchilla, woodland caribou, and pika are some of the best known species of Alpine Tundra.
Antarctic Tundra occurs on Antarctica and on several Antarctic and sub-antarctic islands. Most of it is too cold and dry to support vegetation. In some portions of Antarctica, there are areas of rocky soil that support plant life. The flora presently consists of around 300–400 lichens, 100 mosses, 25 liverworts, and around 700 terrestrial and aquatic algae species, which live on the areas of exposed rock and soil around the shore of the continent. Antarctica’s two flowering plant species, the Antarctic hair grass (Deschampsia antarctica) and Antarctic pearlwort (Colobanthus quitensis) are found on the northern and western parts of the Antarctic Peninsula. The major difference between Arctic Tundra and Antarctic Tundra is that Antarctic Tundra lacks a large mammal fauna, while in Arctic Tundra we find an array of mammals as mentioned above. The reason is that Antarctica is physically isolated from other continents. However, the shores are inhabited by Sea mammals and sea birds, including seals and penguins. Further, some small mammals, like rabbits and cats, have been introduced by humans to some of the subantarctic islands.