Geography 7.3.2 Taiga

Taiga climate

• The taiga has:

  • Long, cold winters (January average -10^oC)

    • Temperatures can reach -50^oC

  • Short, wet summers (July average 15-20^oC) 

    • Summers only last three months

  • Low levels of precipitation (380-650mm annually)

Taiga climate

Interdependence in the Taiga

• The taiga makes up 30% of all forested areas in the world

• All parts of the taiga ecosystem are interdependent

  • A change in one part affects others

• The interdependence of the taiga components means that when one element is affected it then impacts all the other components

• A decline in one species (especially if it is a keystone species) can lead to a decline in other species 

Why are salmon a keystone species?

• Salmon are a keystone species in the taiga

• They provide an essential food source for bears and wolves

  • Wolf diets can be almost 50% salmon

• If the salmon are affected by disease or can no longer migrate back up stream due to a barrier like a dam, the food source is depleted

• This impacts on the wolf population

Why are scots Pine a keystone species?

• Scots Pine is another keystone species

  • Squirrels, voles and mice rely on the pine cones as a food source

  • The deep ridges on the bark provide habitats for many insects as well as lichens and mosses

  • The insects provide food for many birds and small mammals

  • Reduction in the numbers of Scots pine can have a dramatic impact on the food web

  • Plant and animal species populations may decline

Adaptations of Plants in a Taiga Climate

Plants

Needle-shaped leaves: the needle shape and waxy covering reduces water loss (transpiration) and frost damage

Cone shaped: this helps the trees shed snow in the winter

Flexible branches: bend so that they don't break under the weight of the snow and allow the snow to fall off

Wide, shallow roots: avoid the frozen ground but are wide to support the trees and anchor them in strong winds

Seeds in cones: the cones surround the seeds  to protect them from the intense cold

Adaptations of Animals in a Taiga Climate

Animals

Thickly oily fur: moose and bears have thick oily fur which helps to keep them warm

Hibernation: a number of animals including the brown bear, chipmunks and squirrels hibernate during the winter months

Migration: some animals migrate to lower latitudes during the winter months, such as the Canada goose and caribou

Feet: the taiga is often snow covered and some animals feet are adapted to move quickly and effectively through the snow. Caribou have large hooves and the pads turn hard in winter

Summer and winter coats: to ensure camouflage in both winter and summer some animals have brown fur/hair in summer and white in winter such as the snowshoe hare

Why does taiga have a low level of biodiversity?

• Taiga has a low level of biodiversity

• The cold, dry climate means that the growing season is limited to a couple of months

• There is only one layer of vegetation - trees, with mosses and lichens growing on the trees

• The soil is highly acidic

• Nutrient cycling is slow which leads to slow plant growth

Taiga Nutrient Recycling

• The cold and dry conditions in the taiga mean that nutrient cycling is slow

• Growing season is short and there are limited sunlight hours

• The stores and availability of nutrients are small

• There is a lack of chemical weathering due to cold conditions

• The largest store of nutrients in the taiga is the litter because the organic matter decomposes very slowly

• The soil is acidic

• Plants grow slowly due to the short growing season

  • This means that few nutrients are stored in the biomass

• Net Primary Productivity (NPP) is lower in the taiga 

Food web

• As in all ecosystems the taiga has a food web which includes:

  • Producers

  • Primary consumers

  • Secondary consumers

  • Tertiary consumers

Taiga food web