ELSS - Case Studies - Amazon

Question 1

What area does the Amazon rainforest occupy?

Answer 1

more than 6 million km(2)

Question 2

What % lies in Brazil AND what other countries?

Answer 2

70%

Peru, Ecuador, Venezuela, Colombia, Bolivia, Guayana

Question 3

What trees dominate the Amazon?

Answer 3

tall, evergreen, hardwood trees

Question 4

What are the Amazon’s climatic features? (3)

Answer 4

high avg. annual temps (25-30*C)

small seasonal variation in temp

high avg. annual rainfall (>2,000mm) with no dry season

Question 5

What inputs operate in the Amazon water cycle? (2)

Answer 5

precipitation- high avg. annual rainfall (>2,000mm)- interception = high (10% of precipitation); intercepted rainfall accounts for 20-25% all evaporation

Atlantic Ocean- large source of water- brings warm moisture into system

Question 6

What outputs operate in the Amazon water cycle? (2)

Answer 6

evapotranspiration- high rates (high temp, abundant moisture, dense veg.)- approx. 50% incoming rainfall is returned to atmosphere by evapotranspiration- most evaporation is from intercepted moisture from leaves- transpiration = moisture from soil via tree roots

streamflow- Amazon River

Question 7

What flows operate in the Amazon water cycle? (6)

Answer 7

run-off- rapid (high rainfall, intensive rainfall events, well-drained soils)

river discharge- seasonal distribution of rainfall = may peak in 1 or 2 months/year

evapotranspiration

throughflow- horizontal movement of water through soil

throughfall- when water drops

infiltration- vertical movement of water through soil

Question 8

What stores operate in Amazon water cycle? (4)

Answer 8

atmosphere- high temps allow atmosphere store large amounts of moisture (i.e. absolute humidity = high)- relative humidity also high

soil/groundwater- significant water storage in soils & aquifers due to abundant rainfall & deep tropical soils

vegetation- absorb/store water from soil (transpiration release)- interception, released through evaporation (20-25% of all evaporation)

rivers/streams- e.g. Amazon River

Question 9

What physical factors affect the flows & stores in the water cycle? (3)

Answer 9

geology- impermeable catchments = minimal water storage capacity = rapid run-off- permeable & porous rocks (e.g. limestone & sandstone) store rainwater = slow run-off

relief (slopes)- maj. Amazon basin = extensive lowlands- areas of gentle relief, overland flow and throughflow to streams & rivers- mountains = steep catchments with rapid run-off (e.g. Andes in West)- inundation of floodplains (e.g. Pantanal) = store water for months; slowing progress into rivers

temperature- high temp = high evapotranspiration = increased humidity & dev. of thunderstorm clouds and intense precipitation

Question 10

Why are the Amazon’s conditions ideal for plant growth?

Answer 10

humid, equatorial conditions

Question 11

What is the Amazon’s avg. NPP?

Answer 11

high- 2,500 grams/m(2)/year

Question 12

How much biomass is there in the Amazon?

Answer 12

between 400-700 tonnes/ha

Question 13

How much carbon do large forest trees typically store (above & below ground)?

Answer 13

above- 180 tonnes C/ha

below (roots)- 40 tonnes C/ha

Question 14

What does the soil carbon store avg. between?

Answer 14

90-200 tonnes/ha

Question 15

How much carbon does the rainforest absorb?

Answer 15

2.4 billion tonnes/year

Question 16

Flows of carbon in the Amazon (3)

Answer 16

photosynthesis- leaves = evergreen (little seasonal variation) BUT 12hr light/12hr dark = diurnal variation

decomposition- warm, humid conditions = rapid rates- lots of leaf litter (high NPP)

respiration- large vegetation biomass (release of CO2)

Question 17

Stores of carbon in Amazon (2)

Answer 17

soil- 90-200 tonnes/ha

trees- above ground (180 tonnes/ha); below ground (40 tonnes/ha)

Question 18

What physical factors affect the stores and flows of carbon in the Amazon? (3)

Answer 18

temperature- high temps, rainfall, sunlight = high NPP (Amazon responsible for 15-25% all NPP in terrestrial ecosystems) = high plant growth = lots of leaf litter = decomposition

vegetation- large store of carbon- carbon sink (leaves all year round, high NPP)

geology- carbonates largely absent (dominated by ancient igneous and metamorphic rocks) BUT in W parts of basin (close to Andes) outcrops of limestone- slow carbon cycle: significant regional carbon stores

Question 19

What did deforestation in the Amazon average between 1970-2013?

Answer 19

17,500km(2)/year

Question 20

How much of the primary forest has been destroyed or degraded since 1970?

Answer 20

almost 1/5

Question 21

When did devastating floods occur on the Madeira River (largest tributary of the Amazon River)?

Answer 21

April 2014

Question 22

What height above normal did the river reach at Porto Velho during the flood?

Answer 22

19.68m

Question 23

What were the impacts of the flood? (4)

Answer 23

vast expenses of floodplain were inundated

60 people died

68,000 families evacuated

outbreaks of cholera and leptospirosis

Question 24

How has human activity in the Upper Madeira drainage basin modified stores and flows in the water cycle? (3)

Answer 24

deforestation = reduced water storage in forest trees, soils (which have been eroded), permeable rocks (due to more rapid run-off) and in atmosphere

fewer trees = less evapotranspiration = less precipitation

total run-off & run-off speeds have increased = raising flood risks throughout the basin

Question 25

What natural factor in upper basin of the Madeira River contributed to the floods?

Answer 25

torrential rainfall

Question 26

What does converting rainforest into grassland mean in terms of run-off?

Answer 26

increases run-off by a factor of 27

1/2 of all rainfall landing on grassland goes directly into rivers

Question 27

Why are rainforest trees a crucial part of the water cycle? (3 & expl)

Answer 27

extracting moisture from soil

intercepting rainfall and releasing into atmosphere (transpiration)

stabilising forest albedo and ground temperatures

= sustains high atmospheric humidity- responsible for cloud formation and heavy convectional rainfall

Question 28

What was the main driver of the flood AND figures AND impact?

Answer 28

deforestation in Bolivia and Peru

2000-2012: 30,000km(2) of Bolivian rainforest was cleared for subsistence farming and cattle ranching

= massive reduction in water storage and accelerated run-off

Question 29

Local impact of deforestation on water cycle (2)

Answer 29

rainforest to grassland = increased run-off by factor of 27 = 1/2 all rainfall falling on grassland goes directly to river = increased flooding

trees stabilise albedo effect/ground temperatures- deforestation breaks cycle of high atmospheric humidity = cloud formation & convec. rainfall = permanent climate damage

Question 30

Regional impact of deforestation on water cycle (2)

Answer 30

future predictions = 20% decline in regional rainfall

disruption of regional water cycle = forests 100s kms downwind affected too (not just deforested areas)

Question 31

Impact of deforestation on water stores (3)

Answer 31

tree storage- decreased interception

soil- decrease of water in soil = increased soil erosion

atmosphere- less clouds = less moisture stored in atmosphere

Question 32

Impact of deforestation on water transfers (3)

Answer 32

evapotranspiration decrease- reduced interception (evapo); reduced moistures in soils = less absorption (transp)

precipitation decrease- decreased humidity = less cloud formation = less convec. rainfall

run-off increase- more water reaching ground; ending up directly in rivers (less interception)

Question 33

Storage of an undisturbed tropical rainforest (above & below ground)

Answer 33

above ground- total C absorption = 30.4 tonnes/ha- (photosynthesis); total C emission = 24.5 tonnes/ha (respiration)

below ground- soil/biomass = 226 tonnes/ha; roots = 64 tonnes/ha

= carbon sink

Question 34

Storage of tropical forest 10 years post deforestation (above & below ground)

Answer 34

above ground- 12.3 tonnes/ha (photosynthesis); emissions: 6.8 tonnes/ha (respiration); 18.3 tonnes/ha (burning, decomposition, soil erosion)

below ground- soil/biomass = 150 tonnes/ha; roots = 12 tonnes/ha

= carbon source

Question 35

How does replacing trees with agricultural crops exhaust the carbon biomass store?

Answer 35

crop lands/pastures = small amount of carbon in comparison to trees (e.g. soya cultivation = 2.7 tonnes/ha)

Question 36

How does deforestation impact the nutrient cycle?

Answer 36

destroys main nutrient store (trees) and removes most of nutrients from the ecosystem- nutrients no longer taken up by the root systems of trees are washed out of soils by rainwater; and soils, without the protective cover of trees, are quickly eroded by run-off

Question 37

What are the modern strategies to manage the Amazon rainforest sustainably? (3)

Answer 37

protection through legislation of large expanses of primary forest so far unaffected by commercial developments

projects to reforest areas degraded or destroyed by subsistence farming, cattle ranching, logging and mining

improving agricultural techniques to make permanent cultivation possible

Question 38

Examples of legislation to protect the forest (2)

Answer 38

Since 1998, Brazilian govt has established many forest conservation areas- Amazon Regional Protected Areas now cover an area 20x size of Belgium

By 2015, 44% of Brazilian Amazon comprised national parks, wildlife reserves and indigenous reserves where farming is banned

Question 39

What is the Parica project, what does it do?

Answer 39

Rondônia (W Amazon)- aims to develop a 1,000km(2) commercial timber plantation on govt-owned, deforested land

plan is for 20million fast-growing, tropical hardwood seedlings, planted on 4,000 smallholdings, to mature over a period of 25 years- financial assistance given to smallholders for land prep, planting and maintenance of plots

Question 40

How much of a success is the Parica project?

Answer 40

although project is a monoculture and cannot replicate biodiversity of the primary forest, it is sustainable

sequesters carbon in trees and soil; reduces CO2 emissions from deforestation; re-establishes water and carbon cycles; and reduces run-off and the loss of plant nutrients & carbon from the soil

Question 41

What is the indigenous group of Rondônia AND what have they done to help the water and carbon cycles?

Answer 41

Suruí people

scheme that aims to protect primary forest areas degraded by deforestation

e.g. plant seedlings bred in local nurseries in deforested areas around their villages- species chosen provides timber for construction, food crops and, through logging, a sustainable source of income

Question 42

What is the UN’s REDD Scheme AND how does it help?

Answer 42

UN’s Reducing Emissions from Deforestation and Degradation scheme

provides payment to the tribe for protecting the rainforest and abandoning logging- market-based approach involving granting of carbon credits to the Suruí

these credits can be purchased by international companies which have exceeded annual carbon emissions quotas- e.g. 2013, Natura (cosmetics TNC) purchased 120,000 tonnes of carbon credits from the Suruí

Question 43

When did the Suruí join the UN’s REDD scheme?

Answer 43

2009

Question 44

Why is permanent cultivation unsustainable in Amazonia?

Answer 44

low fertility of soils

Question 45

What is diversification AND how does it help?

Answer 45

soil fertility can be maintained by rotational cropping and combining livestock and arable operations

integrating could allow a 5x increase in ranching productivity & slow rates of deforestation

Question 46

What are dark soils AND how do they help?

Answer 46

soils made from inputs of charcoal, waste and human manure- - how Amazon rainforest supported high pop. densities & large urban centres in past

charcoal in these soils attracts micro-organisms & fungi = allows soils to regain their fertility long-term

scientists currently investigating- would allow intensive and permanent cultivation which would drastically reduce deforestation and carbon emissions