8 | Forests under Threat - Taiga Flashcards
Describe the subarctic climate of the Taiga.
- Long cold winters, -40 degrees C
- Short mild summers, 16 degrees C.
- Average precipitation of 500mm (low).
Why is the Taigas productivity so low?
- Plant growth is limited due to short summers = small biomass = low productivity
- Litter store decomposition is slow and stops during winter freeze.
Why is decomposition in the Taiga so low?
- Litter store is made up of pine needles, they are tough and decompose slowly.
Why is the size of the biodiversity store so low?
Nutrients take a long time to get into the soil, pine needles are acidic and only some plants are suitable in acidic conditions. And frozen winters, short summer periods and low precipitation means less plant species and less animal species.
What animal species are attracted?
Migrating birds are attracted as in the summer months there are lots of insects.
What is the predominant plant species in the Taiga?
Mostly made up of conifer trees that don’t drop their leaves autumn.
Give examples of plant adaptations.
Needle shaped leaves.
- Small surface area to reduce water loss compared to the broad leaves of the TRF plants.
- Waxy coating to hinder transpiration.
- Dark green (full of chlorophyll) to help with absorption of sunlight for photosynthesis.
- Little sap, so they don’t freeze easily and can operate in winter.
Why don’t conifer trees shed their leaves?
Energy is low in the Taiga, so growing leaves would take forever. No time to waste when spring comes as trees need to photosynthesize immediately.
Give an adaptation of plants, in regards to shape and position.
- Trees grow close together to gain protection from wind damage.
- Conical shape, downward facing branches so that heavy snow slides off, otherwise the weight of the snow will break the branches.
Give adaptations of animals that stay in the Taiga through its winter months.
- Thick fur coat = insulation.
- Small ears and short tails to avoid frostbite.
- Bears build up fat reserves in the summer in order to hibernate in a den for winter, allowing their body temperature to fall.
- Animals develop winter camouflage (white coat or plumage so they don’t stand out in the snow.)
Give an example of a direct threat to the Taiga forest and its effects.
- Softwood logging has meant that in Russia, its taiga has been clear cut at a rate of 12 million hectares a year.
- No trees = no pine needles = lower soil nutrients.
Give an examples on indirect threats to the Taiga forest and its effects.
- Oil and gas extraction has resulted in spills near Taiga forests.
- There is poor drainage in the Taiga so the oil doesn’t get washed away, the oil remains in the ecosystem and seeps in to the shallow root systems of taiga trees, killing them.
What is acid precipitation and how does it affect the taiga?
- Fossils fuels are burnt in power plants and industries, chemicals such as sulfur dioxide are released, they react with water and oxygen in the and fall as acid precipitation.
- Acid damages plants, kills insects and eggs which reduces the number of migrating birds, kills soil bacteria that prevent nutrients from entering the soil.
What causes forest fires and what are their effects on the taiga?
- Lightning, human activity such as camp fires and gas flares in oil fields.
- The ash left from forest fires has nutrients and plant species benefit.
- However the taiga is not adapted for forests fires as frequent as they are now.
What are the effects of pests and diseases?
- Fungus and mould species damage conifer needles which lowers the amount of nutrients in the soil. Affecting the growth of plant species.
- Young shoots are eaten by insects and pests.
- E.g. silkworm spread into east Siberia, silkworm infestation killed plants.
- Spruce bark beetles kill large numbers of trees.
