Arctic Tundra Biome Flashcards
What is the average temperature range annually in the ATB
-5 - -10 degrees C
What is the temperature during long dark winters?
-20
What causes low annual precipitation?
High pressure and subsiding air
What is the annual precipitation?
150mm
What is the maximum temperature for the short growing season?
10 degrees C
What are the 4 dominant vegetation types?
Mosses, Lichens, Grasses and Dwarf Shrubs
What are the main grazers?
Caribou, Musk Ox and Reindeer
What are the soils like in the ATB
Thin, acidic and low in nutrients
Where do Dwarf Willow and Stunted Birch Trees grow?
Adjacent to seasonal rivers, but only to a maximum height of 30cm due to the short growing season, low nutrient availability and wind exposure
How do they help resist the effects of low temperatures and wind/snow damage?
Growing together in a blanket formation
What are some other adaptations of tundra flora?
- Ability to grow under a layer of snow
- Ability to carry out photosynthesis in cold temperatures
- For flowering plants to produce seeds and flowers quickly once summer begins
How does the permafrost affect the above soil?
Causes waterlogging and gleying (the effect of waterlogging resulting in anaerobic conditions)
What adaptations do plants have referring to the permafrost?
They have short roots to avoid the permafrost and small leaves to limit transpiration
What does limit plant growth result in?
Limited amounts of litter, so there is a slow decomposition of organic matter to give a thin layer of peat.
What does the low temperatures inhibit
Soil formation and the decomposition of organic matter
How is the formation of soil horizons prevented?
Bedrock being weathered by freeze-thaw action and being raised to the surface by frost heave.
What is the projected rate of retreat for the ATB?
15 miles north every decade
What are lichens dependant on?
Winter snow and ice - cannot easily adapt to higher temperatures
How will CC affect migratory herbivores
They will need to alter their grazing ranges, and numbers and ability to reproduce will be threatened by inadequate vegetation. Higher temperatures will also prevent lakes and rivers freezing, limiting their ability to migrate so there will be overgrazing and a decline in reindeer herds
What will be the effect of incremental permafrost thawing.
It could reach a ‘tipping point’ where the amount of methane already released means temperatures are so high the rest of the permafrost can never recover.
What is the positive permafrost carbon feedback?
Currently carbon and methane-storing permafrost is shrinking at an alarming rate as decomposition of organic matter is a heat source - leading to a rise in soil temperatures, further decomposition and increased methane release.
