The Amazon Rainforest Flashcards
What are some facts about the Amazon rainforest?
> The Amazon is the worlds largest tropical rainforest, it covers 40% of the South American Landmass.
> It has a hot, Very wet climate and it’s vegetation is very dense.
> It is home to up to 1 million plant species as well as some endangered species such as the Amazonian Manatee.
How does the water cycle impact the Amazon?
> The Amazon is very wet as there is lots of evaporation over the Atlantic Ocean, creating wet air that is blown over the Amazon.
> Warm temperatures mean that evapotranspiration is high, further increasing the Amazons rainfall.
> The rainforest has a very dense evergreen canopy that increases interception which decreases the amount of water flowing into the rivers and it does so much slower.
How does the Carbon cycle impact the Amazon?
> The Amazon rainforest is the worlds largest carbon sink, storing carbon in its soil and vegetation.
The increased C02 in the atmosphere has increased the productivity in the Amazon, the amount of biomass has been increasing.
As a result the sequestered carbon has increased in the Amazon, becoming an even more important Carbon Sink.
However there have been suggestions that despite trees growing quicker they’re dying younger, as a result it may become less of an important sink in the future.
How are Human activities in the Amazon affecting the Carbon and Water cycles?
Effects on the water cycle -
+In deforested areas there is no canopy so the rainfall isn’t intercepted and reaches the ground increasing surface runoff and flashy flooding.
+ Deforestation reduces evapotranspiration meaning less water vapour is placed in the atmosphere reducing rainfall and increasing drought. The Amazon suffered a bad drought in 2010 following above average temperatures and below average rainfall.
Effects on the Carbon cycle -
+ Without roots and a canopy to reduce surface runoff nutrient rich soil is washed away, transferring carbon into the hydrosphere, this also reduces vegetation which decreases photosynthesis.
+ Deforestation means there is less leaf litter so humus isn’t formed so soil can’t support growth further.
+ Drier weather increases the risk of wildfire which can release huge amounts of carbon into the atmosphere.
+ Species may become extinct after being adapted to moist conditions, scientist estimate that a 4°c temperature rise would lead to the death of 85% of the Amazon, this would reduce photosynthesis and increase decomposition.
What attempts are there to limit human impacts on the Amazon?
Selective Logging - Only certain trees are felled , this allows the forest structure to remain in place which allows the forest to regenerate naturally with little impact on the water and carbon cycles.
Replanting - e.g Peru plans to restore 3.2 million hectares of rainforest by 2020, its important that the same trees that were felled are replanted in order to redevelop the carbon and water cycle to their initial states.
Environmental Law - Laws on excessive logging e.g the Brazilian forest code states that landowners most retain up to 80% of their land as rainforests.
Protection - Many countries have now dedicated areas of rainforest as national parks e.g the Brazilian Central Amazon conservation complex was set up in 2003 to protect biodiversity and allow indigenous people to use the forest sustainably.
