The interrelations between organisms and environment on the land constitute “Terrestrial Ecology”.
The most important limiting factors of the terrestrial ecosystems are moisture and temperature.
The word tundra means a “barren land” since they are found where environmental conditions are very severe. There are two types of tundra- arctic and alpine.
Arctic tundra extends as a continuous belt below the polar ice cap and above the tree line in the northern hemisphere. It occupies the northern fringe of Canada, Alaska, European Russia, Siberia and island group of Arctic Ocean.
On the south pole, tundra is very small since most of it is covered by ocean .
Alpine tundra occurs at high mountains above the tree line. Since mountains are found at all latitudes therefore alpine tundra shows day and night temperature variations.
Flora and fauna:
Typical vegetation of arctic tundra is cotton grass, sedges, dwarf heath, willows, birches and lichens.
Animals of tundra are reindeer, musk ox, arctic hare, caribous, lemmings and squirrel.
They are protected from chillness by the presence of thick cuticle and epidermal hair.
Mammals of the tundra region have large body size and small tail and ear to avoid the loss of heat from the surface.
The body is covered with fur for insulation.