elss sg3 Flashcards
general facts and location of ARF
- south america, spread over 9 countries, 70% of rainforest is in Brazil, found between the tropics of cancer (23.5degreesN) and capricorn (23.5degreeS).
- 6 million km2. avg temp = 27 degrees celcius, rainfall = over 2000 mm. seasons tropical rain belt igrates north and south of the equator as seasons change creating pronounced wet and dry seasons.
- MOre than half the world plant and animal species - 300 billion trees. Soil is 20metres deep and nutrient rich.
- 20% of earth oxygen produced by the amazon.
- Rainforest soild are deep due to the chemical weathering of bedrock creating deep soil. Top 20cm of soil is leaf litterm decomposing rapidly.
factors affecting the water cycle in the rainforest
1 - tempurature - high temps all year round = high rates of evapotranspiration, convection is strong leading to atmospheric humidity so lots of clouds and rain.
2 - geology - impermeable areas (amazon basin) have minimal water storage capacity, permeable and porous rock store rainwater and runoff.
3 - relief - amazon basin is in lowlands = more oevrland flow. water moves though soil. ANdes = steep relief = rapid runoff.
Atlantic ocean provides water to ARF, warm temps = evaporation = convection = condensationof clouds over atlantic ocean. TRade winds blow them over the amazon.
factors affecting the carbon cycle in the ARF
1 - tempurature - more sunlight = higher tempuratures = more photosynthesis = large store of carbon in biomass.
2 - vegetation - climate = ideal for plant growth = dense vegetation = lots of photosynthesis so high net primary produtivity = 2500 g per ha cubed.
3 - organic matter in soil = upper layer of soil (humus) holds lots of decomposing elaf litter creating a large carbon sotre in organic matter of soil
deforestation in the amazon
- 80% of deforestation is for cattle ranching, 10% commercial agriculture, 3% due to logging, cleared for cattle pasture and soy farms.
- fires - forests are burned to clear areas - can quickly get out of control.
- lack of law enformcement - more illegal activity eroding the amazons finite resource base.
It can be done sustainably through shifting cultivation - small area of land cleared and burned, ash is a fertiliser to the soil, tribes grow crops in this area, when soil gets exhausted, tribe repeats in a different area and the previous area heals
impact of deforestation in the amazon
- deforestation = less interception from vegetation and biomass and less water stored, means more surface runoff increasing river discharge.
Maderia: - 2011, Maderia River, a tributoary of the Amazon river in peru, bolivia, brazil.
- large areas of drainage basin in Brazil and Bolivia underwent deforestation especially in the Andean highlands.
- terrential flows of water, 60 people died,68,000 families displaced, 5000 Brazilian homes are destroyed and flooded, 364-a roadimpassable, shortages of food and fuel, disease outbreaks.
management
ARPA: conservation areas, 33% of amazon is comprised of them, ARPA credited with 37% decrease in deforesation, rotects 60 million ha, largest tropical forest conservation prgramme ever,but still illegal logging, in 2020 logging rose 55%, President Bolsonaro delcared protecdted areas were an obstacle for growth.
UN-REDD: pays surui tribe to protect forestin carbon credits, businesses buy carbon credits e.g. natura bought 120,000 tnnes, money made from surui funds sustaible projects e.g. eco tourism holidays, scrapped in 2018 when found diamonds, weakens surui culture, credits dont offse pollution.
Agroforestry: integration of trees and shrubs into crop and animal farming to create sustainable ecosystems, CREES collaborate with banana farmers to impact this, manages1500 acres.
