The Amazon Rainforest

Question 1

describe the Amazon Rainforest

Answer 1

it is the world’s largest tropical rainforest and covers 40% of south america, it has a hot, very wet climate and the vegetation is dense, it is home to 1 million plant species, 500 species of mammal and 2000 species of fish

Question 2

how does the water cycle impact upon the Amazon?

Answer 2

• it causes the amazon to be very wet as there is lots of evaporation over the atlantic ocean and the wet air is blown towards the amazon
• warm temperatures mean that evaporation is high in the rainforest which increases the amount of precipitation
• the rainforest has a dense canopy meaning that interception is high, less water flows into rivers and it does so more slowly
• it is populated by species that are adapted to high humidity and frequent rainfall

Question 3

how does the carbon cycle impact upon the Amazon?

Answer 3

• the amazon stores lots of carbon in its vegetation and soil so it’s a carbon sink
• the increasing concentration of co2 has led to increased productivity so therefore more photosynthesis so the amount of biomass is increasing
• the amount of co2 sequestered by the amazon has increased
• trees are growing more quickly but dying younger so cannot be reliable for the future

Question 4

how has deforestation affected the water cycle?

Answer 4

there is no tree canopy to intercept rainfall so more water reaches the ground surface
there is too much water to soak into the soil which increases surface runoff and increases the risk of flooding

Question 5

how has deforestation affected the carbon cycle?

Answer 5

heavy rain washes away nutrient-rich top layer of soil which transfers carbon stored in the soil to the hydrosphere
there is less leaf litter so humus isn’t formed, this limits the amount of carbon which is absorbed
trees remove co2 from the atmosphere and store it, so fewer trees means more atmospheric co2

Question 6

how has climate change affected the carbon cycle?

Answer 6

• temperature is increasing and rainfall is decreasing which leads to drought, the amazon had severe droughts in 2005 and 2010
• plants and animals living in the amazon have adapted to moist conditions so frequent or long periods of dry weather could lead to extinction of some species
• droughts can lead to forest fires which can destroy large areas of forest which released co2 into the atmosphere
• scientists predict that a 4c temperature rise could kill 85% of the amazon rainforest

Question 7

how does selective logging reduce human impacts?

Answer 7

only some trees are felled which is less damaging than felling all the trees
the forest structure is kept which means the canopy is still there and the soil isn’t exposed
therefore the forest is able to regenerate

Question 8

how does replanting reduce human impacts?

Answer 8

new trees are planted to replace the ones that cut down, peru plans to plant 3.2 million hectares of forest by 2020
the same type of tree needs to be planted so that the variety of trees is kept for the future

Question 9

what environmental laws can reduce human impacts?

Answer 9

• ban the use of wood from forests that are not managed sustainability
• ban excessive logging
• control land use e.g. brazilian forest code says that landowners have to keep 50-80% of their land forest

Question 10

how can the amazon be protected?

Answer 10

• many countries have set up national parks and nature reserves, for example the central amazon conservation complex in brazil was set up to protect an area of 49,000km2
• damaging activities such as logging can be monitored and prevented