The Amazon Rainforest Flashcards
Locational context
> The Amazon is the worlds largest tropical rainforest and covers 40% of the South American landmass.
> It has a hot, very wet climate and the vegetation is very dense.
> Many groups of indigenous people live in the Amazon rainforest.
> Its home to 1 million plant species, over 500 species of mammals and over 2000 species of fish.
How does the water cycle affect the Amazon rainforest?
1) The water cycle causes the amazon to be very wet- there is a lot of evaporation over the Atlantic Ocean, and the wet air is blown towards the rainforest. This contributes to its very high rainfall.
2) Warm temperatures mean that the evaporation is high anyway in the rainforest, which increases the amount of precipitation.
3) The rain forest has a dense canopy- this means tat interception is high. As a result, less water flows into rivers than might otherwise be expected.
4) The water cycle affects the Amazon Environment - it is populated by species that are adapted to high humidity and frequent rainfall.
How does the Carbon Cycle affect the Amazon Rainforest?
1) The amazon rainforest stores lots of carbon in its vegetation and soil, so its a carbon sink.
2) The increasing concentration of co2 in the atmosphere has led to increased productivity in the Amazon rainforest because the vegetation is able to access more co2 for photosynthesis- the amount of biomass has been increasing.
3) The amount of co2 sequestered by the Amazon rainforest has increased, making it an important carbon store.
How does deforestation (human impact) affect the water and carbon cycle?
Effects on the water cycle:
>In deforested areas there is less canopy for an interception to take place, so more water reaches the ground surface. Due to there being too much water to infiltrate into the soil, the surface runoff will occur, which will increase the risk of flooding.
> Deforestation reduces the rate of evapotranspiration, which means less water vapor reaches the atmosphere, fewer clouds form, and rainfall is reduced. This increases the risk of drought.
Effects on the Carbon Cycle:
>Without roots to hold the soil together, heavy rain washes away the nutrient-rich top layer of soil, transferring carbon stored in the soil to the hydrosphere.
> Deforestation means that there is less leaf litter, so humus is formed. The soil cannot support much new growth, which limits the amount of carbon that is absorbed.
> Trees remove co2 from the atmosphere and store it, so fewer trees mean more atmospheric co2, which enhances the greenhouse effect and global warming.
How does climate change have a severe impact on the Amazon rainforest?
1) In some areas temperature is increasing and rainfall s decreasing, which leads to drought. The Amazon had severe droughts in 2005, 2010, and 2015-16.
2) Frequent or long periods of drought could lead to the extinction of some species as many are used to moist weather, therefore making it hard for them to survive in drier conditions.
3) Drought can lead to forest fires, which can destroy large areas of forest releasing lots of co2 into the area.
4) Scientists predict that a 4-degree temperature rise could kill 85% of the Amazon rainforest. This would result in lots of carbon being released due to the occurrence of decomposition and less tree taking in co2.
Are there attempts to limit human impacts on the Amazon rainforest?
Selective logging:
>Only some trees are cut down- most are left standing.
>This is less damaging to the forest than cutting down all the trees in the area. If only a few trees are taken from each area the forest structure is kept- the canopy is still there and the soil isn’t exposed.
Replanting:
>New trees are planted to replace the ones that are cut down. For example, a project in Peru replanted over 115 acres of forest between 2016 to 2019.
> It’s important that the same types of trees are planted that were cut down so that the variety of trees is kept for the future and the local carbon and water cycles return to their initial states.
Environmental Law:
>Laws that ban the use of wood from forests that are not managed sustainably.
>Laws that ban excessive logging
>Laws that control land use, e.g. the Brazilian Forest Code says that landowners have to keep 50-80% of their land as forest.
Protection:
>Many countries have set up national parks and nature reserves to protect rainforests. For example, the Central Amazon Conservation Complex in Brazil was set up in 2003 and protects biodiversity in an area of 49000km while allowing people to use the forest in a sustainable way.
>Within National parks and nature reserves, damaging activities such as logging can be monitored and prevented.
