Topic 8 - Forests Under Threat Flashcards
What are the stratified layers of the rainforest?
Ground layer Shrub layer Under canopy Main canopy Emergent layer
What are the features of the shrub layer?
Between 0-10 metres
Made up of smaller plants
Alligators, jaguars, snakes, insects, orchids
What are the features of the under canopy?
10-20 metres
Young trees competing for sunlight
Insects, sloths, halo monkeys
What are the features of the main canopy?
20-30 metres
Lots of birds
Trees that are tall and straight with few branches
Butress roots
What are the features of the emergent layer?
30-40 metres
Tallest trees
Wide butress roots
Birds, insects and butterflies
What does interdependent mean?
Interrelated / depend on each other.
What are biotic factors?
The living parts of an environment, such as plants (flora), animals (fauna) and microorganisms.
What are abiotic factors?
The abiotic factors are the non-living parts of an environment.
What biotic and abiotic factors are interdependent?
- Climate
- Soil
- Water
- Plants
- Animals
- Humans
What’s an example of interdependence?
Sunlight and rain (abiotic-climate) keep plants alive and growing.
How are plants adapted to the climate?
- Stratified layers
- Butress roots
- Drip tips
What are the features of the ground layer?
Very dark, very steamy
2% of light reaches it
Dead and decaying plant matter
Infertile (no nutrients) soils
What are butress roots?
Stretch from the ground to 2 metres or more up the trunk, which help anchor the tree to the ground to stop them falling over and ensure they take in as many nutrients as they can.
What do drip tip leaves do?
Thick waxy leaves with pointed tips.
Pointed this channel the water to a point so it runs off, so the weight of the water doesn’t damage the plant.
Waxy leaves stop algae or moss growing over the leave surface which would block sunlight preventing photosynthesis.
What ways are animals adapted to the tropical rainforest?
- Strong limbs - spend day climbing and leaping
- Flaps of skin to glide between trees
- Camouflaged
- Nocturnal (night is cooler so save energy)
- Adapted to low light levels - sharp sense of smell and hearing
- Can swim to cross river channels
What are the 3 stores in the nutrient cycle?
- Biomass (living organisms)
- Litter
- Soil
What are the ways nutrients are lost?
- Surface run off
* Leaching
What are the inputs in the nutrient cycle?
- Breakdown of rock
* Rain
Why are nutrients cycled quickly in tropical rainforests?
- Trees are evergreen, so dead leaves and other matter fall all year round.
- Warm, moist climate means that fungi and bacteria decompose the dead organic matter quickly. The nutrients released are soluble and are soaked up by the soil.
- Dense vegetation and rapid plant growth means that nutrients are rapidly taken up by plants roots.
Why do rainforests have high levels of biodiversity?
- Not much climate change so there has been lots of time for plants and animals to evolve to form new species.
- Layered structure provides lots of different habitats - plants and animals adapt to become highly specialised to there particular environment and food source so lots of different species develop.
- Hot and wet all year. Very productive because of high rate of nutrient cycling. Plants and animals don’t have to cope with changing conditions and there is always plenty to eat - so they are able to specialise.
What do food chains show?
What’s eaten by what in an ecosystem.
What do food chains start with?
A producer.
Producers make there own food using energy from the sun.
What are producers eaten by?
Primary consumers
What are primary consumers eaten by?
Secondary consumers
What are secondary consumers eaten by?
Tertiary consumers
What happens when these organisms die?
They get broken down by decomposers.
What do food webs show?
How all the food chains overlap.
Ecosystems usually contain many different species - which means lots of different possibile food chains.
Why are food webs in the tropical rainforest very complex?
- So many different species so loads and loads of links.
* Some animals can be both primary and secondary consumers.
What are causes of deforestation?
- Local demand for fuel wood
- Mineral resources
- Electricity (HEP)
- Commercial hardwood logging
- Commercial farming
- Subsistence farming
- Demand for biofuels
Why does local demand for fuel wood cause deforestation?
Local people chop down trees to use for fuel for cooking or to burn to make charcoal.
Why does Mineral resources cause deforestation?
Gold, copper and iron ore are often found in tropical rainforests. Explosives are sometimes used to clear earth or deep pits are dug to reach the deposits.
Why does electricity (HEP) cause deforestation?
Many tropical rainforest have large rivers. Building dams to generate hydroelectric power floods large areas of forest behind the dams.
Why does commercial hardwood logging cause deforestation?
Trees are felled to make furniture and for construction. Road building for logging also requires more tree clearance.
Why does commercial farming cause deforestation?
Forest is cleared to make space for cattle grazing, or for huge palm oil or soya plantations.
Why does subsistence farming cause deforestation?
Forest is cleared so farmers can grow food for themselves and their families.
Why does demand for biofuels cause deforestation?
Biofuels are fuels made from plants. Growing the crops needed to make biofuels takes up large amounts of land - trees have to be cut down to make space for them.
What are Environmental impacts of deforestation?
- No trees to hold soil together, heavy rain washes it away. Leads to landslides and flooding.
- No tree canopy to intercept rainfall and tree roots to absorb it. More water reaches soil. Reduces soil fertility as nutrients are washed away out of reach of plants.
- Trees remove CO2 from the atmosphere. Burning vegetation to clear forest release CO2. More CO2 adds to greenhouse effect.
What are indirect threats the the Tropical Rainforest?
- Ecosystem stress
* Drought
How is climate change and drought an indirect threat?
Temperature is increasing and rainfall is decreasing which leads to drought.
Drought leads to ecosystem stress - plants and animals living in tropical rainforests are adapted to moist conditions, so many species die in dry weather. Frequent or long periods of drought could lead to extinction of some species.
Drought can also lead to forest fires, which can destroy large areas of forest.
Global actions to protect Tropical Rainforest:
What is REDD?
A scheme that aims to reward forest owners in poorer countries for keeping forests instead of cutting them down.
Advantages of REDD?
- Deals with cause of climate change as well as direct impacts of deforestation
- The forest is protected so remains a habitat for species - biodiversity is not lost
- Everyone benefits from reducing emissions and its a relatively cheap option to do so.
Disadvantages of REDD?
- Deforestation may continue in another area
- Aspects of REDD are not clear meaning that it may be possibile to cut down rainforests, but still receive the reward if they are replaced with other types of forests
- Preventing activities (agriculture and mining) may affect local communities who depend on the income.
Global actions to protect the tropical rainforest:
What is CITES?
An agreement to tightly control the trade in wild animals and plants.
Advantages of Cites?
- The issue is tackled at a global level.
* Raises awareness of threats to biodiversity through education.
Disadvantages of CITES?
- Although individual species are protected their habitats aren’t - they could still go extinct e.gl due to impacts of climate change.
- Some rules are unclear e.g on the trade of ivory
- Not all countries are members - some countries even promote the trade of materials from endangered species.
Why are deforestation rates rising in some areas?
- Poverty - more small-scale subsistence farmers.
- Foreign debt - huge market for goods from tropical rainforest so easy way to make money to pay back debt
- Economic development - projects to promote development open up areas to logging, farming and mining,
Why is deforestation decreasing in some areas?
- Government policies - invested in ecotourism, pays landowners to reforest areas
- International condemnation - naming and shaming companies involved in deforestation
- Monitoring systems - satellite data to track forest loss. Authorities can act more quickly to stop illegal logging.
Economic challenges involved in successful forest management?
1) Economic benefits are only seen in the long term - this affects poorer countries who need income immediately.
2) Sustainable forestry is more expensive, so can be difficult to persuade private companies to adopt sustainable methods
3) Sustainable forestry schemes are funded by government departments and NGOs. If the priorities of these organisations change, funding could stop.
Environmental challenges of sustainable forest management?
1) If trees are replanted the new forest may not resemble the natural forest - trees are replaced but entire ecosystem may not be restored.
2) Trees that are replanted for logging in the future may be slow growing - companies may chop down more natural forest while they are waiting for the new trees to mature.
3) Selective logging can damage lots of trees in the process of removing the target trees.
Social issues of sustainable forest management?
1) Provides fewer jobs for local people than conventional forestry so many locals won’t see the benefits. So they may turn to illegal logging which is difficult to police.
2) If the population of a forest area increases the demand for wood and land from the forest increases. Sustainable forestry is unlikely to provide enough resources to match increasing demand.
What are the 2 alternative livelihoods methods to protect the tropical rainforest?
Ecotourism
Sustainable farming
What is ecotourism?
1) Tourism that minimises damage to the environment and benefits the local people
2) Only a small number of visitors are allowed into an area at a time. Environmental impacts are minimised.
3) Provides a source of income for local people. Raise awareness of conservation issues and bring in more money for rainforest conservation.
4) If local people are employed in tourism they don’t have to log or farm to make money meaning fewer trees are cut down. If a country’s economy relies on ecotourism there’s an incentive to conserve the environment.
What is sustainable farming?
Sustainable farming techniques protect the soil so the land remains productive - there is no need to clear new land every few years.
They include:
• Agro forestry - trees and crops are planted at the same time, so that the roots bind the soil and the leaves protect it from heavy rain.
• Green manure - plants which add nutrients to the soil as they grow are planted to maintain soil fertility
• Crop rotation - crops are moved between different fields each year with one left empty so the soil has time to recover.
How are Taiga forests interdependent?
1) Plants gain nutrients form the soil and provide nutrients to the animals that eat them. In turn, animals spread seeds through their dung, helping the plants to reproduce.
2) The cold climate causes plants to grow slowly and also to decompose very slowly. This means hat the soil is relatively low in nutrients - further reducing the ability of plants to grow.
3) In summer, the trees absorb heat from the sun and shade the ground below - this prevents the permafrost below from thawing. The permafrost provides water for the plants.
How are taiga plants adapted to the cold, dry climate?
- Evergreen
- Needles
- Cone shaped
What does it mean by evergreen?
They don’t drop their leaves in a particular season, so they can make the best use of the available light.
Hat does it mean by needles?
This reduces water loss from strong, cold wind because it reduces the surface area.
What does cone-shaped mean?
Heavy winter snowfall can slide straight if the branches without breaking them. The branches are also quite bendy so are less likely to snap.
How are animals adapted to the climate?
Migratory - move long distances through the forest in order to find food.
Well insulated
Hibernate to conserve energy and survive the winter
Why is there slow nutrient cycling in the taiga?
- The cold, dry climate means that nutrient cycling is much slower
- Low temperatures mean that it takes a long time for the litter to be broken down and added to the soil - conditions are too harsh for many decomposers. This means the soil isn’t very fertile.
- The cold climate also means that plants grow slowly - the rate of transfer of nutrients from soil to plants is low.
What is the biggest store in the Taiga?
Litter store
Facts about the nutrient cycle in the taiga?
- Few nutrients are added through precipitation or weathering.
- Quite a lot of the nutrients are lost through runoff and leaching.
Why do taiga forests have lower biodiversity?
- Land was covered by ice so species have had relatively little time to adapt to the current climate
- Simple structure means not many different habitats, fewer varieties of species.
- Taiga forests are much less productive and nutrients take a long time to be returned to the soil because it’s so cold. Growing season is short. Not much food available, constant struggle for survival.
- Some groups of animals are underrepresented because they can’t cope with the cold climate.
What are some direct threats to the taiga?
- Logging for softwood
- Exploitation of fossil fuels
- Pulp and paper production
- HEP
- Exploitation of minerals
How is logging for softwood a direct threat to the taiga?
Trees are cut down so they can be made into housing, furniture and matches.
How is exploitation of fossil fuels a direct threat to the taiga?
Trees are cleared to extract gas and oil from the ground.
Example: Tar sands
• Tar sands is earth containing thick black oil which can be processed into fossil fuels. Extraction of the tar sands often involves open pit mining or strip mining.
How is pulp and paper production a direct threat to the taiga?
Felled trees are mashed into a pulp and used to make paper.
How is HEP a direct threat to the taiga?
Dams to generate hydroelectric power from rivers in taiga forest flood large areas of land.
How is exploitation of minerals a direct threat to the taiga?
Many taiga forests are rich in minerals. Lots of trees are chopped down to make way for mines as well as access roads.
What 3 things contribute to loss of biodiversity in the taiga?
- Acid rain
- Pests and diseases
- Forest fires
How is acid rain causing a loss of biodiversity?
1) Burning fossil fuels releases gasses, such as sulfur dioxide and nitrogen oxides. These dissolve in water in the atmosphere to form acids. When it rains or snows, the acids are deposited on plants and soils.
2) Acid rain damages plants leaves and makes it harder for them to cope with the cold. It can also make the soils to acidic to support growth and kills organisms in lakes and streams.
How is pests and diseases causing a loss of biodiversity?
1) Pests and diseases cause damage to organisms
2) Many pests and diseases are specific to one species. As there is often a single tree species in a particular area in taiga forests it’s easy for pests and diseases to spread and multiply they can do a lot of damage.
3) It is thought that warming caused by climate change is making it easier for pests and diseases-causing pathogens to survive.
How is forest fires causing loss of biodiversity?
1) Climate change is leading to warmer, drier conditions in taiga forests. This is increasing the frequency of fires and making the fire season longer.
2) Forest fires can destroy huge numbers of trees and may change the distribution of species as some species are better at recolonising burnt areas. They may also break forest up into smaller sections, which makes it hard for migratory animals that need a lot of space to find enough food.
What are conservation methods for the taiga?
- Creating a wilderness area
- Cresting a national park
- Sustainable forestry
What is a wilderness area?
An area that is undisturbed by human activity that is managed with the aim of protecting the landscape.
What are strengths of wilderness areas?
- Highest level of protection - most human activity is banned
- Usually covers a very large area so large-scale processes can still take place e.g. animal migrations
What are challenges of large wilderness areas?
- The large remote areas are hard to police
- There is economic pressure on governments from logging, mining and energy companies who want to use the resources
- There is pressure from companies and tourists to build roads to allow greater access
What are national parks?
An area that is mostly in its natural state that is managed to protect biodiversity and promote recreation.
What are strengths of national parks?
- May be established to protect particular species
- Often cover a large area
- Unsustainable human activity such as logging and mining is not permitted
- There is good access for tourists and recreational users
What are challenges of national parks?
- Must take into account needs of indigenous communities who may use the land for hunting
- Tourism may be required to pay for the conservation, but access roads, infrastructure and pollution from tourists can harm the ecosystem
What is sustainable forestry?
Ways of harvesting the timber for the forest without damaging it in the long-term
What are strengths of sustainable forestry?
- Limits can be placed in the number of trees felled of the size of the clear cut areas to allow the forest to regenerate
- Companies may be required to regenerate the area after logging
- Selective logging means some tree remain to become part of the new forest
What are challenges of sustainable forestry?
- Some countries struggle to enforce the restrictions
- There may be a lack of clear management or information about the ecosystem
- Different groups may not agree with the rules and restrictions
Conflicting views on managing taiga forests:
Protection
1) Taiga forests store lots of carbon - deforestation will release some of this as CO2 which causes global warming.
2) Some species are only found in taiga forests. Because they are adapted to the conditions, the destruction of the habitat could lead to their extinction.
3) Many indigenous people depend on the forest for their traditional life.
Conflicting views on managing taiga forests:
Exploitation
1) The demand for resources is increasing - people need the wood, fuel and minerals that the forests provides.
2) Forest industries provide a lot of jobs.
3) The exploitation of the forest generates a lot of wealth for the countries involved.
