tundra tundra comes from the finnish word ‘tenturi’, which means barren or treeless land

TUNDRA

Tundra comes from the Finnish word ‘tenturi’, which means barren

or treeless land

Types of TundraTypes of Tundra

• Arctic Tundra: • determined by latitude

• Circumpolar Regions – (Arctic circle)

• Northern Europe/Asia, Alaska, Northern Canada

• Alpine Tundra: determined by altitude• Above treeline (the elevation at which trees no

longer grow)• As latitude goes up (further North), treeline goes

down• Can occur on any continent, regardless of latitude

Tundra CharacteristicsTundra Characteristics

• Cold Temperatures– Because of the tilt of the

Earth, high latitude regions receive very little solar energy for parts of the year

– Those sun rays that do reach these areas come at an angle and carry less energy

– Alpine tundra—the air is thin, traps very little heat and provides little insulation from the cold temperatures of the upper atmosphere


• High Winds– Clash of air temperatures from cold tundra

regions and warmer regions cause high winds– High winds lead to high erosion and damage

to vegetation– Winds also carry heat from Earth away (wind

chill) causing even colder temperatures


• Low Precipitation– Tundra regions are sometimes called “frozen

deserts”– Some tundra regions have less than 5

inches/year– Can vary—some areas have more

precipitation, but mostly in the form of snow

Tundra CharacteristicsTundra Characteristics• Frozen soils

– Permafrost is the term for soil that remains frozen throughout the year

– Most tundra areas have permafrost soils, including some alpine areas

– The top layer of some permafrost areas melts during the warmer months. This is called the ‘active layer’

– The permafrost doesn’t allow many things to grow in the tundra, and what does grow does it slowly and has other adaptations


• Permafrost, cont’• Because of the freezing

and thawing patterns, the ground takes on some specific topographic features– Polygon-cracks in Earth– Pingo-cone shaped hill

with a solid ice core– Thermokarst- ‘sink-hole’

caused by melting ice


• Low Biodiversity– Because of harsh conditions, very few

organisms are able to survive in the tundra biome

– The organisms that are there have special adaptations to help them survive

Tundra AdaptationsTundra Adaptations

• Migration– Helps animals to avoid severe winter conditions of the

Tundra– Seasonal movement

• Animals typically go South in fall and come back North in Spring

– Range of migration can be 100’s of miles up to 10,000 miles

– Examples• Many species of birds, such as whimbrels and arctic terns• Caribou migrate out of tundra to taiga for winter• Tundra fish, such as char, migrate to deeper waters for

winter


• Food– Dormancy

• Many plants, insects and microscopic organisms ‘shut down’—no need for food

• Birds, mammals and fish must continue to breathe—cannot become completely dormant

• hibernation, torpor are ways animals reduce functions to minimum needed for survival

--Food storage• many animals gorge in late summer to gain energy rich fat

for winter• some animals may gather grasses or other plants during

summer and stash away for winter months


• Food, cont’– Examples

• Arctic ground squirrels and marmots hibernate

– heart beat slows (squirrel: from 200-400bpm to 7-10bpm)

– body temperature drops – breath rate slows

Bears go into a state of torpor (not a true hibernator

– heart rate slows– body temperature stays the same– lemmings feed on stems of dormant

plants– pikas and voles store large piles of dried

grass near nests


• Shelter– Many animals use soil, snow or tundra plants for shelter during

winter• Soil/ground

– Subterranean”– provides insulation and protectionSnow– “Subnivean”– provides insulation and protection– can be ~20° F warmer below snow than above it

• Examples– Lemmings, voles, shrews, weasels, arctic ground squirrels,

insects, most plants live beneath snow during winter– Bears make dens in the ground on south facing slopes

Tundra AdaptationsTundra Adaptations• Body Shape

– Large size with short appendages• heat loss decreases as surface area

to body weight ratio decreases

– Examples• Tundra hares are larger and have

shorter ears than desert hares• Arctic foxes have shorter ears than

desert kit foxes• Lemmings are larger and have

smaller ears and tails than other mouse-like animal


• Fur, Feathers and Movement– Fur and feathers act as insulation—trap air

• Two coats, or two layers of fur or feathers• Some animals have hollow hairs to trap more air• Some plants have small ‘hairs’ or waxy coating to

reduce water loss

– Movement• generates body heat


• Fur, Feathers and Movement, cont– Examples

• Wooly louswart is a plant covered with fine hairs• Ptarmigan have feathers that coat their entire body, even their feet!• Musk-ox have many layers of dense fur• certain insects ‘shiver’ their flight muscles to

generate heat, allowing them to remain active when other insects are too cold to move


• Growth and Reproduction– Cold blooded animals grow slowly or not at all when

conditions are unfavorable• some arctic moths take up to 10 years to reach adulthood• That same moth in a warmer climate would reach adulthood

in 2 years

– Warm blooded animal’s growth and reproductivity varies with conditions as well.

• Brown bears in Arctic do not breed until 8 years old • Brown bears in Southern Alaska breed when 3-4 years• Some birds lay fewer eggs, or no eggs at all in years with

late snowmelt


• Color– Warmth

• Dark fur absorbs more solar heat than light fur

• Light fur absorbs less body heat than dark fur (therefore transferring less to surroundings)

– Camouflauge• many animals become

white for the winter months to blend with the snow

• seasonal color change has more to do with waning daylight than temp.


• Plant adaptations– Leaves

• tundra plants adapted to photosynthesize at low temps and with low light

– Roots• store sugar in roots so they can grow leaves under snow, allowing

them begin photosynthesis as soon as the leaves are exposed

– Flowers• take years to store up the energy needed for flowering• buds develop over the course of 1 to 2 years

– Reproduction• because flowering takes so long, plants reproduce by rootstocks or

runners (underground ‘branches’ that resurface as a new plant)


• Animal antifreeze– pump intracellular(inside cells) fluid full of

ethylene glycol (a sugar)• prevents cells tissue from freezing and therefore

being damaged• Wood frogs can withstand temps well below

freezing

Human ImpactHuman Impact

• Not much human inhabitation in the tundra, but because of mines and the oil industry, the population is increasing

• This means more roads, towns, etc.• Some people worry that humans are

impacting the habitat of some animals, but modifications are made– Eg. There are some places the pipeline is

raised high enough for caribou to pass under

Human ImpactHuman Impact

• Because of the short growing season and slow growth rate, vegetation takes a really long time to recover

• When the active layer melts, water pools in the soil, making it muddy and prone to surface damage

• It has been said that 4-wheeler tracks or even footprints on the surface of the tundra might remain visible for decades!

Tundra SummaryTundra Summary

• Generally windy with cool temperatures

• Flat landscape with very few trees

• Low biodiversity

• Organisms adapt to harsh conditions

• Two types: Arctic (high latitude) or Alpine (high altitude)

tundra tundra comes from the finnish word ‘tenturi’, which means barren or treeless land

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