Tundra Biome

Tundra Biome – UPSC Environment Notes

The Arctic Tundra Biome stands as the northernmost biome on Earth. It spans the lands from the Arctic Circle to the polar ice cap, extending as far south as the Hudson Bay area of Canada and the northern part of Iceland. Characterized by the scarcity of vegetation, the term “tundra” is derived from the Finnish word tunturi, which means ‘treeless plain.’ A significant feature of the tundra is the presence of permafrost.

The term permafrost is a contraction for permanently frozen soil, commencing within a meter of the soil surface. During winter, nearly the entire soil becomes frozen. In summer, the surface soil thaws, but the deeper layers of permafrost remain frozen. Permafrost imposes restrictions on the depth to which plant roots can penetrate into the soil, and it acts as a barrier preventing the growth of trees.

Distribution of Tundra Biome

There are three types of Tundra Regions worldwide, namely Arctic Tundra, Alpine Tundra, and Antarctic Tundra. In the Northern hemisphere, the Tundra is present north of the Taiga belt.

Salient Features of Tundra Biome

The key characteristic of the Tundra is Permafrost, a permanently frozen soil composed mainly of gravel and finer material. The soil remains frozen from 25-90 cms down, creating a plain landscape with few trees. Polar Tundra regions experience only two seasons: summer and winter. Winters are extremely cold and dark, with temperatures in Arctic Tundra regions dropping as low as -50°C. In contrast, summers see a slight temperature rise, causing the permafrost to melt at some points, making the ground soggy.

Arctic Tundra is known for its cold, desert-like conditions. The average winter temperature is -34°C (-30°F), while the average summer temperature ranges from 3-12°C (37-54°F), allowing for the biome to sustain life. The Arctic Tundra has a diverse range of flora, including low shrubs, sedges, reindeer mosses, liverworts, grasses, and over 400 varieties of flowers and lichen.

Plants in the Arctic Tundra are adapted to withstand sweeping winds and soil disturbances. They are short, grouping together for protection against the cold, and can carry out photosynthesis at low temperatures and light intensities. The growing seasons are short, leading most plants to reproduce through budding and division rather than flowering.

The fauna in the Arctic Tundra is also diverse, featuring herbivorous mammals like lemmings, caribou, and arctic hares, as well as carnivorous mammals such as arctic foxes, wolves, and polar bears. Migratory birds like ravens, falcons, and various species of gulls inhabit the region, along with insects such as mosquitoes, flies, and arctic bumble bees. Fishes like cod, salmon, and trout are also present.

Animals in the Arctic Tundra are adapted to long, cold winters, with additional insulation from fat. Many animals hibernate due to food scarcity, while others migrate south during winter. Reptiles and amphibians are scarce due to the extremely cold temperatures, and the population continually oscillates due to constant immigration and emigration.

Climate of Tundra Biome

Temperatures fluctuate between 15.5 °C in summer and -60 °C in winter, with mean temperatures persisting below 0°C for six to 10 months annually. The northernmost part of this biome experiences nearly 24 hours of sunlight during parts of summer, while it encounters close to 24 hours of darkness during parts of winter. The annual precipitation hovers around 150 to 250mm per year.

Natural Vegetation of Tundra Biome

The vegetation in Tundra biomes is composed of ‘cryophytes.’ Owing to the cold climate and short growing season, the predominant vegetation in the tundra consists of herbaceous plants, including grasses, mosses like reindeer moss, and lichens. The limited woody plants present in the tundra, such as dwarf willows, endure the harsh conditions. Plants in this biome exhibit dormancy during the long winters, slowing down their normal life functions, with a significant portion of their biomass existing below ground. The tendency of plants to remain close to the ground is influenced by temperature inversion.

Animal Life of Tundra Biome


The Tundra is home to both (i) resident animals and (ii) migrant animals. Resident animals possess relatively larger sizes and specific body structures enabling them to endure harsh winters. This biome hosts numerous large mammals, including caribou, polar bears, arctic foxes, and musk ox. Additionally, smaller mammals like lemmings and arctic hare, which serve as prey for larger mammals, are prevalent. These prey animals adapt by sporting brown fur in the summer and white fur in the winter, aiding camouflage in the changing landscape. Despite low insect biodiversity, certain insects in the arctic tundra, such as mosquitoes, can form large populations.

Fragile Ecosystem of the Arctic Tundra

From the provided description, it’s evident that the Arctic Tundra ecosystem is highly delicate due to the scarcity of abundant plant life. If primary consumers struggle to find sufficient food, it disrupts the entire food chain, impacting predators.

In the Arctic Ecosystem, the foundational layer consists of primary producers (plants) at the bottom of the pyramid. These resources are severely limited, sensitive to even slight reductions in sunlight and water availability. The presence of permafrost in the ground further complicates water drainage, making it challenging for plants to thrive. Occupying the middle tier are primary consumers like lemmings, musk oxen, and insects, relying on the limited plant life. At the top are small predators such as snowy owls, arctic foxes, and polar bears.

Due to the scarcity of primary producers, the ecosystem and food chain in this fragile Arctic environment exhibit continuous population oscillations. This vulnerability implies that the extinction of just one species could have the potential to disrupt the entire Tundra ecosystem.

Global Warming & Tundra Climate

Global warming introduces increased uncertainty to the future of the tundra. The rising temperatures associated with global warming facilitate the spread of woody plants, posing a potential threat to moss and lichen species across 40% of the biome in the upcoming years.

Conclusion

In conclusion, the Arctic tundra biome is characterized by its extreme climate, with temperatures ranging from summer highs to winter lows that challenge both resident and migrant animals. The vegetation, primarily composed of cryophytes, adapts to the short growing season and cold conditions. The resident animal population, including iconic species like caribou and polar bears, showcases strategies for survival in the unforgiving environment. Notably, the intricate relationships between larger and smaller mammals highlight the delicate balance of this ecosystem. Despite the challenges, the arctic tundra harbors unique adaptations and biodiverse life forms, demonstrating nature’s resilience in one of the Earth’s most challenging environments.

FAQs on Tundra Climate

Q. What types of animals are well-adapted to the extreme climate of the Arctic tundra biome?

Answer: Resident animals like caribou, polar bears, arctic foxes, musk ox, as well as migrant animals, demonstrate adaptations in size and body structures to survive severe winters.

Q. How do smaller mammals in the tundra, such as lemmings and arctic hare, adapt to the changing seasons?

Answer: Smaller mammals in the tundra, acting as prey, adapt by changing fur color – brown in summer and white in winter – facilitating camouflage in the dynamic landscape.

Q. What is the significance of the brown fur in summer and white fur in winter for prey animals in the Arctic tundra?

Answer: The color-changing fur of prey animals is crucial for camouflage, helping them evade predators and survive in the Arctic tundra’s ever-changing environment.

Q. How do resident animals, like caribou and polar bears, navigate and survive the severe winters in the tundra biome?

Answer: Resident animals employ various survival strategies, including size, body structures, and behavioral adaptations, to endure the harsh winter conditions in the Arctic tundra.

Q. What role do cryophytes play in the vegetation of the Arctic tundra, and how do they cope with the short growing season and cold climate?

Answer: Cryophytes, the vegetation of the tundra, adapt to the short growing season and cold climate by exhibiting unique characteristics that enable them to thrive in this challenging environment.

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