Paper 3: Forests Under Threat Flashcards
What does biodiversity mean?
The number of different plant and animals species in an area.
Statistics on animal and plant species in the Amazon rainforest:
-16,000 different tree species
-40,000 different plant species
-1300 bird species
-6 different sloth species
-10% of the worlds plants and animals live in the Amazon rainforest.
(In comparison the UK only have 30 native tree species)
Why is biodiversity exceptionally high in rainforests?
- Climate is suitable for all year round growth and reproduction.
- Rainforests are ancient and have a stable climate different species have evolved to be better suited there.
- the multiple layers in the rainforest provide numerous different specialised habitats. Plants and animals have evolved to take advantage of these.
What do all rainforests have in common?
The equatorial climate.
- there is no dry season with at least 60mm of rainfall each month; some get 3m of rain each year.
- Temperatures are high at 26°c-32°c all year round meaning no winter or summer.
What factors mean rainforests can grow continuously, with a huge abundance of life both animal and plants?
Continuous heat, water and sunlight are available all year-round meaning this can occur.
Describe the emergent layer in the rainforest:
Hardwood, evergreen trees that have broken through the dense canopy layer below to reach sunlight. Monkey and birds live up here. Trees are 165 ft +.
Describe the canopy layer of the rainforest:
Dense canopy layer is where most the animals in the rainforest live. 30% of world birds love here. 2/3 of animals in rainforest live here. Most animals live here because there is much food here.
Describe the under canopy layer in the rainforest:
Little sunshine reaches this sees, so plants have to grow larger leaves to reach sunlight. Plants seldom grow to 12ft. Home to a large concentration of insects. Contains young trees trying to reach canopy.
Describe the forest floor:
Very dark, almost no plants grow here and the ones that do have leaves with a large SA. As hardly any sun reaches the forest floor things decay quickly. Only 1/10 million seeds grow here. Plants have large leaves and animals such as, Jaguars live here.
What are drip tip leaves and how are they adapted?
Most rainforests plants have thick, waxy leaves with drip tips; these shed water quickly to prevent leaves rotting.
What are lianas and how are they adapted?
These climbing plants use trees as their ‘trunk’ - their stems cling to trees and climb up to the sunlight in the canopy, while getting water and nutrients from the soil below.
What are Epiphytes and how are they adapted?
These plants live in the canopy on trees and have evolved to get all their nutrients form water and air rather than the soil (which is 10 meters below)so their roots dangle in mid air.
How are evergreen hardwood trees adapted for the rainforest?
Mahogany, teak and ebony trees have tall slender trunks with no branches on them, but huge triangular buttress roots. The roots support the enormous weight of the tree; leaves and branches and are only at the very top, where the sunlight is.
How are plans and trees in the rainforest adapted?
- buttress roots
- drip tip leaves
- lianas
- epiphytes
How are sloths adapted for the rainforest?
- huge claws allow them to hang upside down in their branches, while their fur grows away from their feet to help shed rain when upside down.
- green algae growing in their fur helps camouflage the from predators.
How are primates adapted for the rainforest?
- lemurs and monkeys have evolved to love in the canopy where most of their food is.
- their long tails are used for balance and most have strong claws to grip trees and branches.
How are big cats adapted for the rainforest?
- Jaguars, tigers and leopards all have camouflaged fur.
- the dark and light fur patches blend in with the shade and sunlight on the forest floor.
How are birds adapted for the rainforest?
-Rainforest birds have very loud calls because it is easier to her a mate than see them in the dense canopy; parrots and macaws have powerful beaks to break open nuts.
Rainforest statistics:
- covers 7% of earths rainforest
- home to 1/2 of earths species.
- Amazon is 2.5million mile square.
- 6000 mammal species
- 70,000 different insect species
- 260 inches of rain each each year
- 4000 mile long Amazon river(2nd largest river)
Key words for tropical rainforest nutrient cycle:
Inputs: something put into a system.
Outputs: something produced by a system.
Store: where something is kept.
Flow: how something moved from one store into another.
Recycling: how material/ energy is used in a system.
What are nutrients?
All plants need nutrients grow. These are tiny amounts of chemical elements and compounds like nitrogen, potassium, phosphates and magnesium that plants need.
How do animals affect the nutrient cycle when they eat and die?
When nutrients are eaten by animals nutrients feed into them. As animals die, those nutrients are recycled - so they move around biomes via the nutrient cycle.
What external factors affect the nutrient cycle?
- nutrients can be added to an ecosystem by PRECIPITATION and WEATHERING.
- they can also be removed by runoff or leaching(when nutrients are washed out of the soil by water moving through it.)
- they are taken up from the soil as plants (or biomass) grow.
- they are returned to to it when they die; first as litter (or decaying leaves and twigs) on the soil surface and then back into the soil as litter decays.
What is the purpose of the nutrient cycle?
To keep soil healthy. Nutrients move between biomass, litter and soil in a continuous cycle.
What are the key differences between the rainforest nutrient cycle and the theoretical nutrient cycle in normal biomes?
- larger biomass store: layers of vegetation and huge trees store large amounts of nutrients.
- smaller litter store and large decay transfer: in hot, wet conditions bacteria and fungi decay dead matter quickly, returning nutrients to the soil.
- larger growth transfer: plants grow all year, so draw nutrients up from the soil rapidly.
- larger weathering input: chemical weathering processes (e.g solution) are faster in hot wet climates, so release nutrients into the soil from rocks.
- a larger leaching output: Heavy rainfall throughout the year brings in nutrients, but the constant flow of water through the soil removes them (leaching).
What are the 2 affects on the nutrient cycle when trees are cut down?
- without the forest to protect it, litter and soil are easily eroded by heavy rains.
- as rainforest soils contain few nutrients, land cannot be farmed for long before having to move on.
What is a food web?
A complex network of overlapping food chains that connect plants and animals in biomes.
What is a food chain?
A simple chain that shows which, animals each what and how nutrients and energy are transferred through the animals up the chain.
What is the basic energy source for food webs?
Sunlight for plants to carry out photosynthesis to convert energy in the form of glucose. As one organism feeds on another, energy passes between them.
What can happen if food webs are disrupted?
Food webs represent a delicate balance between species. If disrupted, biodiversity can be reduced. E.g. if certain trees are cleared, or a species of plant dies because of a disease then primary consumers that eat it will suffer as their food source has gone.
Why are food webs in the rainforest so complex?
Most animals are quite selective about what they eat creating more complex food webs.
What are the differences between detrivores and decomposers?
Detrivore: they consume their material to break it down. E.g insect, maggot.
Decomposer: don’t eat their food, decompose it externally (e.g bacteria/ fungi)
What is the taiga like?
Largest biome on earths surface. Stretches from 50°N-70°N, across northern parts of Asia, North America, covers most of Canada, Alaska, Finland, Sweden and parts of Russia. It is a subarctic climate. Covers a vast 390 million km squared, makes up 30%of worlds remaining forest.
What is the Taigas climate like?
- Subarctic climate
- dominated by cold winters, average temperature rarely above 16°c and can reach -40°c in the winter.
- Low precipitation rates at around 350-750mm a year, snow remains on ground for many months.
- short wet summers of three months when temperatures can rise up to 20°c.
- long cold dry winters with several months below freezing as low as -20°c.
What are the trees in the Taiga like?
The trees are coniferous(evergreen) and have adapted to cold climate- their shape allow snow to fall, instead of weighing on branches and their pine needles prevent damage by wind or snow.
What is the Taiga also called?
Boreal forest
Why is biodiversity in the Taiga low?
- Plants and animals can only survive if they are specially adapted to the cold climate; that means reptiles and amphibians are rare.
- the growing season in on 4-5 months long, meaning in winter there is little food.
Animals have to adapt to very cold winters. Plant stop growing, snow cover makes grazing even dead plants difficult and temperatures are bitterly cold.
How are organisms adapted in the Taiga?
Many mammals have thick, oily fur to help retain body heat and provide water proofing.
Because food is scarce, some animals hibernate e.g bears, bats and squirrels.
300 species of birds live in the Taiga in the summer, eating insects and breeding. However, another 270 species migrate away for winter because of the cold and lack of food.
How are wolves adapted for the Taiga?
- coats made up of woolly fur to provide insulation with long guard hairs to keep put moisture.
- large paws have fleshy pads and claws for traction and can spread to provide better support in the snow.
- smell 100x better than humans and sight 20x better. their vision is motion sensitive so can see well in the dark.
How are grizzly bears adapted Taiga?
- omnivores so can survive on both plants and animals.
- fur coat have many layers of fur keeping it warm in winter.
- its claws are the right length to climb trees that surround its forest home.
- hibernate to avoid having to find food in winter.
- layer of flat to allow them to stay in their dens in the winter.
How are long eared owls adapted Taiga?
- camouflage- bark like fur
- sharp claws to cling onto branches.
- eyes have adapted to see things far away. Sharp ears to hear noises far away e.g pray.
How are Canada lynx’s adapted Taiga?
Its feet have fur covered pads and are silent in the snow so it can ambush pray as its not a very fast animal. It distributes its weight to make it silent.
How are coniferous trees adapted Taiga?
-thick bark to protect against the cold. Cons shaped with flexible branches which help them cope with heavy snow fall.
How are needle like leaves adapted Taiga?
- thin and waxy to reduce water loss.
- evergreen nature mean that the needles can photosynthesise wherever this is sufficient light.
- prevent damage form frost.
How are shallow tree roots adapted for the Taiga?
- wide shallow tree roots to support the tree but avoid frozen ground.
- get nutrients from soil top as they have shallow roots.
How are white spruce’s adapted for the Taiga?
- needles retain heat/shed snow and lose less water.
- waxy coating on needle keeps water in.
What does net primary productivity mean? (NPP)
This is a measure of how much new plant and animal growth - or biomass - is added to a biome each year, measure in grams per square meter per year.
When is net productivity highest?
When there is plenty of sunlight, high temperatures and precipitation. Biomes with cold or dry seasons have lower productivity.
What is the NPP in tropical rainforests?
2200 grams/square meter/per year
What is the NPP in temperate forests?
1200 grams/square meter/per year
What is the NPP in the Taiga (boreal rainforest)?
800 grams/square meter/per year
What is the NPP in the tundra?
140 grams/square meter/per year
Why are their smaller flows of nutrients between stores and smaller stores in the Taiga?
- precipitation is lower and chemical weathering is limited by cold temperatures.
- most nutrients are in litter because not much decaying happens as it is so cold so bacteria and fungi struggle to decay the litter.
- the biomass store is small because trees grow for only a few months of the year.
- The soil is permafrost, so is frozen so not much can grow here.
What does deforestation mean?
Means the deliberate cutting down of forests to exploit forest resources (timber, land and minerals).
What is a direct threat to the rainforest?
Involves deliberate cutting down of trees for timber, to make roads or to convert the forest to farmland.
What are indirect threats to the rainforest?
Come from pollution, global warming or disease.
How many species get extinct each year?
40,000 species die each year which is about 109 a day. However, in the next 50 years we will only loose 0.7% of all species.
What reasons do deforestation occur?
- Poverty
- debt
- economic development
- demand for resources
Why does deforestation occur because of poverty?
In many LICs local people cut down small areas of forest for land to farm because they have no other way of making a living.
Cutting rainforests down requires people, therefore reducing unemployment.
Why is economic development a risk to the rainforest?
Most tropical forests are in the developing world. In order to develop their economies, forest is sacrificed in place of roads, expanding cities, and to dam rivers and build hydroelectricity power (HEP) stations.
For a developing city trading goods is important to make good trading links.
Why is a countries debt a risk to the rainforest?
If a government is in debt they can sell valuable resources from rainforest to other countries and get profit and then pay their debt off. So countries are driven to cut down forests, export timber, or grow cash crops to pay off debts.
Why is demand for resources a risk to the rainforest?
Tropical rainforests contain raw materials. These include timber, but also oil, gas, iron ore and gold. To get these, forests have been destroyed. Land also needed to feed growing populations.
Expensive rainforest goods for medical industry (herbs and special plants).
What percentage of the rainforests is used for what?
Cattle ranching- 60%
Small scale, subsistence agriculture- 33%
Fires, mining,urbanisation, road construction, dams- 3%
Logging, legal and illegal- 3%
Large scale commercial agriculture including soybeans- 1%
What is mineral exploration?
Coltan is a mineral used in mobiles. It is dug from the ground form shallow mines by poor families, and sold for a few pence to TNCs (middlemen who sell it on). Large areas of forest are cleared to dig mines.
What is hydroelectricity power?
E.g the Tucurui Dam in Amazonia, Brazil. The dam opened in 1985 and cost US$6billion. Most of the electricity is used for iron ore and bauxite mines owned by mining TNCs like Vale, especially the worlds largest iron ore mine at Grand Carajas. The reservoir flooded 1750km squared of rainforest and the mines it power still cause deforestation.
What are biofuels and how do they affect the rainforest?
E.g palm oil in Indonesia. Indonesia has 6 million hectares of palm oil plantations and plans another 4 million. Palm oil is a tropical plant whose fruit contains oil used in cosmetics and foods e.g shampoo. It is increasingly used to make biodiesel. Huge areas of rainforest are burnt for plantations.
What causes different rates of deforestation?
Poverty- in low-income countries (LICs) like Burundi.
The palm oil industry in Indonesia.
Protection of forest in some middle-income counties (MICs) e.g Malaysia, Brazil, which have lower rates of deforestation.
Isolation- e.g the Democratic Republic of Congo has very low rates of deforestation because it is inaccessible. The rate is likely to increase as forest is opened up and poverty drives people to cut it down.
Give some examples of direct threats to the rainforest:
HEP: Needed to produce electricity and also help to control flooding.
Transport: e.g roads. These divides up parts of the rainforest and can cut of connections between different systems.
Mining: the Amazon includes bauxite, iron ore, gold, silver and diamond.
Cattle ranching: brings money into the country and provides food and jobs for the countries growing population.
Agricultural/farming: provides food for the rainforest communities and poor landless people of Brazil.
Logging: tropical hardwood such as, ebony and mahogany can be sold for a good price abroad.
What would happen if temperatures rose by 1°c?
10% of land species face extinction. Alpine, mountain and tundra biomes shrink as temperature rise.
What would happen if there was a 2°c rise on temperature?
15-40% of land species face extinction. Biomes begin to shift towards the poles and animal migration patterns and breeding time change. Extreme weather at unusual times of the year, such as heat waves and blizzards, affect pollination and migration.
