Tundra
Dry, Cold, and Windy
Photograph by Rich Reid
Tundras are among Earth's coldest, harshest biomes. Tundra ecosystems are
treeless regions found in the Arctic and on the tops of mountains above the tree
line (alpine tundra), where the climate is cold and windy and rainfall is scant.
Tundra lands are snow-covered for much of the year, until summer brings a burst
of wildflowers.
Mountain goats, sheep, marmots, and birds live in mountain, or alpine, tundra
and feed on the low-lying plants and insects. Hardy flora like cushion plants
survive on these mountain plains by growing in rock depressions where it is
warmer and they are sheltered from the wind. Plants that grow in the tundra
include grasses, shrubs, herbs, and lichens. They tend to have shallow roots
and flower quickly during the short summer months.
Most of the plants in the tundra are perennials that come back each year from
the same root. This allows them to grow during the summer and save up
nutrients as they lay dormant for the winter. They also tend to have hairy stems
and dark leaves. This helps them in absorbing energy from the sun.
The Arctic tundra, where the average temperature is 10 to 20 degrees Fahrenheit
(-12 to -6 degrees Celsius), supports a variety of animal species, including Arctic
foxes, polar bears, gray wolves, caribou, snow geese and musk-oxen. The
summer growing season is just 50 to 60 days, when the sun shines 24 hours a
day.
The few plants and animals that live in the harsh conditions of the tundra are
essentially clinging to life. They are highly vulnerable to environmental stresses
like reduced snow cover and warmer temperatures brought on by global
warming.
The Arctic tundra is changing dramatically due to global warming. Already, more
southern animals like the red fox have moved onto the tundra. The red fox is now
competing with the Arctic fox for food and territory, and the long-term impact on
the sensitive Arctic fox is unknown.
It is the Arctic's permafrost that is the foundation for much of the region's unique
ecosystem, and it is the permafrost that is deteriorating with the warmer global
climate. Permafrost is a layer of frozen soil and dead plants that extends some
1,476 feet (450 meters) under the surface. In much of the Arctic it is frozen year
round. In the southern regions of the Arctic, the surface layer above the
permafrost melts during the summer and this forms bogs and shallow lakes that
invite an explosion of animal life. Insects swarm around the bogs, and millions of
migrating birds come to feed on them.
With global warming, the fall freeze comes later and more of the permafrost is
melting in the southern Arctic. Shrubs and spruce that previously couldn't take
root on the permafrost now dot the landscape, potentially altering the habitat of
the native animals.
Another major concern is that the melting of the permafrost is contributing to
global warming. Estimates suggest that about 14 percent of the Earth’s carbon is
tied up in the permafrost. Until recently, the tundra acted as a carbon sink and
captured huge amounts of carbon dioxide from the atmosphere as part of
photosynthesis. This process helped keep the amount of this greenhouse gas
from accumulating in the atmosphere.
Today, however, as the permafrost melts and dead plant material decomposes
and releases CO2, the tundra has flipped from a carbon sink to a carbon
contributor.
Other Facts about the Tundra:
• The word tundra comes from a Finnish word tunturi, which means treeless
plain or barren land.
• Lemmings are small mammals that burrow under the snow to eat grasses and
moss during the winter.
• Polar bears come to the tundra for the summer where they have their babies.
• Animals in the tundra tend to have small ears and tails. This helps them to lose
less heat in the cold. They also tend to have large feet, which helps them to
walk on top of the snow.
The Inuit people of Alaska live on the tundra.
What you need to know about…
Tundra:
Climate:
Where can this biome be found on the Earth?
Types of plants:
Types of animals:
How do the plants and animals adapt to their environment:
Risks that threaten this biome: