Tundra

What is it?

Is biome where the tree growth is hindered by low temperatures and short growing seasons

Where is it?

On the map it is represented in the orange and is mainly found in Iceland, Canada and Norway. There is also alpine tundra where high altitudes create similar conditions to those found at high latitudes (e.g Rockies, Himalayas, Alps)

PLANT ADAPTATIONS:

How does a short thermal/hydrological growing season affect tundra plants?

Problem= Plant growth only begins when there is an air temperature of 6°C. The growing season only lasts 1-2 months, and the life cycles of the plants are completed very quickly resulting in an environment with a low NPP. 

Adaptions:

1. Most of the plants are perennial and store food in tubers and rhizomes during summer which then allows for rapid growth in the Spring.
2. Many of the plants are evergreen and therefore have no need to grow new leaves, their dark leaves absorb insolation which they can then use to photosynthesise.
3. Some of the flowers form buds a year in advance so then don't waste time in the growing season

How has the Arctic poppy adapted?

• Turns the head of the plant to follow the sunlight 
• Low-lying=limits evapotranspiration=reduces water loss

How has the Purple Saxifrage adapated?

• Is perennial so can live for many years
• grows on shallow soils and bare outcrops
• Leaves are covered in dense hairs (Retains heat)
• Grows in dense clumps (reduces wind resistance)
• Can self-pollinate (there are few pollinating insects around in early spring) 

How does the climate and type of vegetation affect the soils?

Mainly made up of gley soils which easily become waterlogged. This reduces the amount of oxygen and ferric/ferrous compounds. There is also the problem of leached minerals this is due to there being more rainfall than evaporation causing the leaching of minerals downwards leading to an elluviated zone with few minerals and hardpan lower down due to the accumulation of minerals.

ANIMAL ADAPTATIONS:

Byson:

Behavioural:

• Migrate

Physical:

• Large volume:surface area ratio (reduces heat loss)
• Long nostrils (warm up air that enters into the body)
• Extremely dense coat

Arctic Foxes:

Behavioural:

• Migrate but have home dens

Physical:

• Can survive -50°C
• Best insulating fur
• Increased blood circulation to their paws

Why are cold environments considered to be fragile?

Why is NPP low in cold environments?

• Limited insolation from sun due to curviture of the Earth, leading to low amounts of photosynthesis
• Very short days in winter due to tilt of the Earth
• High winds=High transpiration rate+plant damage due to abrasion
• Unavailable water 
• No/thin soil due to lack of weathering+low NPP meaning limited minerals and nutrients

How does this make these environments fragile?

• Limited insolation=plants are limited in photosynthesis=lack of energy available=if destroyed can't be replaced (due to low NPP and recovery rates)=leading to a high proportional impact