Distribution

• polar environments

  antarctica and the arctic circle

  also found within any country that aligns with the 10 degree July (northern hemisphere) and January (Southern hemisphere) isotherm
• periglacial environments

  high latitudes

  this includes north america (alaska) and asia (siberia)
• alpine environments

  high altitudes

  for example, the andes mountain range
• polar characteristics


  -60 degrees average

  low precipitation at 100 mm a year

  clearly defined seasons due to orbital cycles (6 month periods)

  due to the polar cells, there is high pressure and a lack of cloud cover (creates the polar high)
• polar soils

  frozen all year round

  nutrient poor

  slow decomposition
• polar vegetation

  lichen -> epiphytes that are composed of a symbiotic relationship between green algae and fungus

  moss -> have no wooded root system

  both slow growing and are very hardy
• periglacial climate

  cold temperatures

  low precipitation

  defined seasons
• periglacial soils

  thin acidic active layer

  mostly infertile

  permafrost covers most of the landscape

  freeze and thaw cycles
• periglacial vegetation

  small plants as permafrost prevents long root systems

  the taiga forest in siberia can support larch trees

  freeze and thaw cycles mean plants have a very short growing window each year
• alpine climate

  seasonal variation

  there are cold winters and warm summers

  30 cm of rainfall on average per year

  temperatures decrease with altitude

  beyond the tree line snow fall increases
• alpine soils

  freeze and thaw cycles

  slow nutrient cycle

  reddish colour as it is rich with iron

  has high decomposition rates due to the elevated acidity
• alpine vegetation

  bare rocky ground can only support low lying plants

  for example, cotton grass which has a short growing season and dark leaves filed with chlorophyll

  elevation above the tree line means trees cannot grow due to the persistent cold and low nutrient levels