Climatic conditions: Extremely cold and dry
i. Adapted to short growing season and extreme cold climate.
ii. Trees lacking, except near rivers and sheltered slopes.
iii. Lack of tall plants as a consequence of the requirement to balance a heat budget and conserve moisture
iv. Tree roots not deep enough to survive.
v. Summer thaw turns it into a quagmire of puddles, bogs and shallow lakes.
vi Surface covered with a mat of lichens, mosses, grasses, sedges.
1. During short summer large number of migratory birds, especially waterfowl invade the tundra to feed on.
2. Except for ptarmigan, tundra birds are migratory using the short period of reproduction and surviving the rest of the year elsewhere Jaegers, geese, shore bird and songbird.
3. Most creatures either burrow such as lemming
ii. Migrate such as caribou, reindeer, and musk oxen
4. Limiting factor is severe cold and shortage of radiant energy. Various adaptations:
i. Subcutaneous fat – insulator prevents heat from body
ii. Hair is raised and brought up into more or less vertical position.
iii. Blood vessels in the skin constrict as the blood is directed from surface to deeper layer reducing loss of heat from blood to surrounding.
iv. Increase in metabolic rate.
v. Allows only few species and primary consumers therefore the biome is vulnerable.
vi. Small herbivore as arctic ermine and snowy owl have white coats that help them camouflage.
vii. Tundra community variable and fragile low diversity low growth rate.