Tundra Biome
Savannah Alderson
Average winter temperature in the tundra
Have you ever wondered where some of the coldest parts of the world are located? Or what can survive in those areas? Or what resources are available to the organisms living in the bitter cold? About 20% of Earth's land is tundra, and it is home to vegetation and critters that have adaptations allowing survival in winters averaging -34°C. Unfortunately, this incredible biome is being threatened by global climate change and other human activities.
Where Are Tundra Biomes Found?
Areas highlighted in blue are tundra.
Tundras can be further divided into three categories.
Arctic tundra is located between boreal forests and the Arctic polar ice cap in areas like Canada, Russia, Greenland, and Scandinavia.
Alpine tundra is located at the top of high elevation mountains such as the Rocky Mountains, Andes, and Himalayas.
Antarctic tundra is located on the land of Antarctica that is not frozen year-round.
What is the climate like in a tundra?
Average temperatures in a tundra are below freezing (0°C) for six to ten months throughout the year. The average temperature during winter in the Arctic tundra is -34°C.
Tundras usually receive less than 25cm (10 inches) throughout the year, which classifies tundras as a desert.
Arctic and Antarctic tundra climates are formed by similar factors, while alpine tundras exist for a few different reasons. At Arctic and Antarctic latitudes, little solar radiation is received in these areas throughout the year. Some Arctic tundras may get warmer in the summer, but the winters are bitterly cold and dark due to lack of solar radiation. Alpine tundras are typically in less extreme latitudes. Alpine tundras are found at high elevations where soils are too thin and temperatures are too cold for trees to habitate. All of the tundra biomes are characterized by high winds. The lack of trees and other barriers prevent slowing of the wind.
What do tundras look like?
Tundras are treeless, and the topography of Arctic tundras depends on the physical location of the tundra and past geologic activity. Some Arctic tundras are very flat while others have mountains or hills. By definition, alpine tundras are found in high elevation mountain ranges. Water resources also vary by physical location of the tundra, but all receive less than 10 inches of precipitation annually on average. Some tundras are located near the ocean while others are inland without access to large bodies of water. Antarctic tundras occur along the coast and on Antarctic islands that are warmer than inland Antarctica due to lower elevations and higher latitudes at the coast. The rest of Antarctica is frozen year round and uninhabitable by most tundra species.
Soils in the tundra are mostly permafrost. Permafrost is soil that has been frozen for at least two consecutive years and is rich in organic carbon from dead plants and animals. Roots of plants are unable to penetrate the permafrost, which is why trees cannot grow in the tundra. The active layer of soil is the small portion of soil that thaws during the summer which allows plants with shallow roots to grow.
What lives in tundras?
Due to the harsh environment of the tundra, biodiversity in tundra biomes is lower than biodiversity in other biomes. Species often have special adaptations that allow survival in nearly inhospitable areas of the tundra.
Vegetation in tundras grow low to the ground to preserve warmth. The vegetation also has shallow roots to access nutrients in the shallow active layer of soil. The growing season in tundras is very short. Conditions for plant growth usually only last 6-10 weeks during the summer.
Arctic Willow (Salix arctica), Cottongrass (Eriophorum angustifolium), Arctic moss, and Boreal pixie-cup lichen (Cladonia borealis)
Peary Caribou (Rangifer tarandus pearyi), Snowy owl (Bubo scandiacus), and Polar bear (Ursus maritimus)
Adaptations of some tundra species
Muskox (Ovibos moschatus)
The muskox has several adaptations that make it possible to survive the brutal winters in the tundra.
The muskox has two layers of fur: a long, outer coat and a wooly undercoat, which is shed in the warmer summer months.
Muskoxen have short, stocky bodies which reduces body mass to surface-area ratio. This helps the animal conserve body heat and reduce heat loss.
Arctic fox (Vulpes lagopus)
Arctic foxes have fur all over their bodies, including the soles of their paws, to keep them warm, and their muzzles and ears are small, which is ideal for conserving body heat.
Arctic foxes burrow in the ground where it is warmer and protected from the blustery winds of the tundra.
Another adaptation the Arctic fox has is the color of its coat. In the winter, the coat is white which blends into the snowy tundra while in the summer, the coat is brown, which is more suitable for the rocky ground.
Rock ptarmigan (Lagopus muta)
The rock ptarmigan also has a change of color with the change of seasons. By the summer, these birds' feathers have changed from white to brown.
The rock ptarmigan's reproduction and migration patterns are also dependent on the time of year which allows them to find necessary warmth and resources.
Eggs are laid by late May and are incubated for 20-22 days. The chicks usually remain with the parents until August. In September, rock ptarmigans tend to move around, but by October, most have migrated to lower elevation areas where they will withstand the winter as a nomadic species.
Arctic hare (Lepus arcticus)
The Arctic hare's thick fur is brown in the summer and white in the winter suited to blend in with their environment.
Their body is built to reduce body mass to surface-area ratio. Their bodies are larger, and their ears are smaller than other species of hare. Also for warmth, Arctic hares may huddle together with other Arctic hares in shelters dug in the snow.
Arctic mosquito (Aedes nigripes)
This species of mosquito has an antifreeze-like chemical in their body to help them survive in the frigid environment by lowering the freezing point of its bodily fluids.
Threats to the tundra
Tundras, as they are known today, were formed at the end of the most recent ice age around 10,000 to 40,000 years ago. Many tundra biomes are found near ice sheets and glaciers. When ice sheets and glaciers melted as climate warmed at the end of the last ice age, conditions for tundras arose in areas we find Arctic tundras today; however, the tundra biome is threatened by human-caused, or anthropogenic, global climate change.
Average yearly global temperatures are rapidly increasing. As atmosphere temperature rises, permafrost melts and soil temperatures rise, which has several implications for the biome.
Logan Berner, a global change ecologist with Northern Arizona University, stated, "The Arctic tundra is one of the coldest biomes on Earth, and it’s also one of the most rapidly warming."
Much of the area highlighted as tundra biome in this map had a 2-4°C increase in 2022 compared to the 1951-1980 average temperature.
Thawing Permafrost -- Changing Planet
Landsat data from NASA/USGS has shown a 38% increase in greenness of the Arctic tundra from 1985 to 2016. Global warming causes tundra vegetation to increase in growth and density, as well as woody shrubs invading the habitat of native tundra vegetation. The soil temperature and moisture increases as the atmosphere warms which also leads to thawing of the permafrost soil layer in the tundra. As permafrost thaws, the organic carbon begins to decompose and release carbon dioxide and methane into the atmosphere. These greenhouse gases contribute to additional insulation and warming of the atmosphere and thus is a positive feedback system. Permafrost may contain large pockets of ice. When thawed, the soil above the melted ice does not have support and may collapse. If structures or roads are built on melting permafrost, this can be a hazard to humans.
To monitor permafrost, NASA's Soil Moisture Active Passive (SMAP) collects soil moisture data via satellite. It can measure the moisture content of the top two inches of soil on the Earth's surface and if it is frozen.
Arctic greening and browning trends from 1982-2020
In a 2006 study by Walker et al., they found that plants respond rapidly to experimental warming in the tundra biome, and there is observed short-term decreases in biodiversity of the tundra with 1-3°C increases in temperature. A meta-analysis was performed on data from plant community measurements from 11 controlled tundra warming experiments. All sites showed change in tundra vegetation. After two growing seasons with increased warmth, there was decreased species diversity. There was an increase in height and cover of woody plants, particularly deciduous shrubs. Changing from herbaceous to woody plants may further increase warming by absorbing more radiation feeding a positive feedback system. In the study, warming occurring over a short period may have led to local extinctions before species could migrate. Global climate change will decrease tundra biodiversity at least in the short-term.
Other human activities that negatively impact the tundra are mining, drilling for oil and gas, and introducing invasive species. Species not typically found in the tundra, such as the red fox, have been able to expand their geographic range into the tundra due to climate change and are competing for food and resources with the native Arctic fox.
How can we help the tundra?
- Decrease greenhouse gas emissions
- Decrease electricity use at home
- Eat a plant-based diet which typically uses less land and water and emits fewer greenhouse gases than the production of meat and dairy products
- Use public transit if it is available to you
- Protest actions and projects that will directly harm the tundra ecosystem, oil and natural gas pipelines and drilling
- Vote for elected officials who support actions that stop climate change
- Spread the word!
Sources
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Langlois, A. (2012). Arctic tundra. Canadian Wildlife Federation. Retrieved from https://www.hww.ca/en/wild-spaces/arctic-tundra.html
Lomolino, M. V., Riddle, B. R., & Whittaker, R. J. (2017). Biogeography: Biological diversity across space and time. Sinauer associates.
NASA. (2023). What is permafrost? NASA. Retrieved from https://climatekids.nasa.gov/permafrost/
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Ramsayer, K. (2020). Warming temperatures are driving Arctic greening. NASA. Retrieved from https://climate.nasa.gov/news/3025/warming-temperatures-are-driving-arctic-greening/
Rock Ptarmigan Species Profile. Alaska Department of Fish and Game. (n.d.). Retrieved from https://www.adfg.alaska.gov/index.cfm?adfg=rockptarmigan.main
Tundra biome. National Geographic. (n.d.). Retrieved from https://education.nationalgeographic.org/resource/tundra-biome/
The tundra biome. University of California Museum of Paleontology. (1996). Retrieved from https://ucmp.berkeley.edu/exhibits/biomes/tundra.php
U.S. Department of the Interior. (2020). Designed for the Arctic. National Parks Service. Retrieved from https://www.nps.gov/gaar/learn/nature/muskox-designed-for-the-arctic.htm#:~:text=Other%20adaptations%20to%20cold%20include,long%2C%20thick%2C%20brawny%20build.
Walker, M., Wahren, C., Hollister, R., & Wookey, P. (2006). Plant community responses to experimental warming across the tundra biome. Proceedings of the National Academy of Sciences. Retrieved from https://www.pnas.org/doi/10.1073/pnas.0503198103
Woodward, S. L. (1997). Tundra. Biomes of the World. Retrieved from https://php.radford.edu/~swoodwar/biomes/?page_id=89
