tropical rainforest

Question 1

general facts

Answer 1

20-28 degrees
2000 mm
convectional rainfall
covers only 5% but supports over 50% of biotic species

Question 2

soil moisture budget

Answer 2

balance between inputs and outputs is high because precipitation is higher than potential evaporation

Question 3

latosol

Answer 3

high in metal oxides like aluminum
nutrient poor
quick decomposition - ideal microclimate for bacteria
all year growing season - nutrients continuously recycled and reabsorbed
– leaching by heavy rainfall

Question 4

layers of the rainforest

Answer 4

emergent
main canopy
under canopy
shrub layer

Question 5

emergent layer

Answer 5

buttress routes - withstand strong winds
30-35m high

example: mahogany

Question 6

main canopy

Answer 6

continuous layer of trees
most productive layer
dense leaves create shade – prevent sunlight reaching lower layers increases competition

Question 7

under canopy

Answer 7

younger trees that aren’t fully grown
only survive if there are breaks in the canopy
only recieve about 10% of sunlight

example: lianas - form green corridors

Question 8

shrubs layer

Answer 8

little sunlight
have large leaves to absorb as much sunlight as possible

Question 9

drip tips - adaptations

Answer 9

waxy leaves with pointed tips that channel water so it runs off
ensure it does not break off or grow mold

Question 10

abscission - adaptations

Answer 10

leaves fall yearly to allow the trees and plants to grow all year long

Question 11

epiphytes - adapatations

Answer 11

lianas that climb up trees to reach the sunlight - also form bridges across the canopy which allow animals to move around
orchids - hold water in the canopy and prevent further soil leaching

Question 12

sloths - adaptations

Answer 12

slow moving saves energy
algae grown on fur - helps with camouflage
long claws which help them to hang from tall trees and lianas

Question 13

anteaters - adaptations

Answer 13

under the canopy - low light conditions - adapted a good sense of smell

Question 14

characteristics of the rainforest

Answer 14

low latitudes within the tropics
low diurnal range at 5 degrees
no seasons - wet and hot all year round
88% humidity
high biodiversity 50%

Question 15

nutrient cycling

Answer 15

continual yearly growing season
fast recycling of nutrients
– loose leaves all year round
– rapid decomposition due to optimal bacterial conditions
– plants grow quickly when light breaks through the main canopy so nutrient uptake is rapid

leads to large biomass
small litter and soil

Question 16

npp in rainforests

Answer 16

very high

Question 17

humus

Answer 17

organic component of soil that helps retain moisture and nutrients

composed mostly of organic plant matter

Question 18

how does climate impacts the soil

Answer 18

parent rock type can remain the same but different climatic conditions create different soils
high temperatures - determines the rate of chemical and biological decay and influences humification (the formation of humus)
results in a deep profile with many well developed horizons

Question 19

aerated soils

Answer 19

soils with pore spaces has a rich brown colour

Question 20

soil texture

Answer 20

determines permeability
smaller mineral particles = decreased permeability
clay - compact and lacks pore space
soils with ample pore space will allow roots to develop and support vegitation growth

Question 21

soil moisture budget

Answer 21

high - precipitation exceeds potential evapotranspiration
short time lapse between rainfall peaks - never reaches a deficit
water surplus all year round

Question 22

soil importance

Answer 22

important factor in the development of vegitation that has driven ecological change and succession
completely reliant on the rainforest to remain fertile - deforested: nutrient leaches and humus is no longer being replaced

Question 23

mining of minerals - human impact

Answer 23

large scale deforestation strips the soil of nutrients and exposes it to erosion
water clogged with silt leads to downstream flooding
eg: carajas, brazil

Question 24

agricultural practices - human impacts

Answer 24

slash and burn creates pasture for grazing
single cash crops like soy create a monocultural environment - decreases biodiversity and increases vulnerability to ecological change

Question 25

Tilling - human impact

Answer 25

Tilling causes the breaking up of topsoil which releases carbon into the atmosphere, and it’s predicted by within the next 60 years the entirety of the world’s topsoil will be gone Since the 1970s, one third of the global topsoil has been decertified: the process of soil turning to desert. The rate at which we till influences the rate of global desertification. Depleting our soils and releasing sequestered carbon from the pedosphere is accelerating the rate at which carbon is being released into the atmosphere greatly impacting the global carbon budget through a positive feedback loop which is moving the carbon budget away from equilibrium.

Question 26

animal husbandry

Answer 26

breeding maintenance and slaughtering of livestock consuming 70% of agricultural land 80% deforested areas in brazil are used for grazing of livestock

Question 27

agroforestry and crop diversity

Answer 27

Peru - working towards replenishing soils the project itself is comprised of having a multitude of crops being planted to enable the microorganisms within the soil to have access to a variety of root types and allow the micronutrients to be replenished in a way that is sustainable and will restore the optimum microclimate so that autotrophs can photosynthesize, absorbing more carbon from the atmosphere than is being released into it.

Question 28

road construction - human impact

Answer 28

highways connect parts of the rainforest that were previously inaccessible encouraging human development eg: transamazonian highway extends 6000km into the rainforest

Question 29

global impacts of human development

Answer 29

forests store up to 100x more carbon that fields - loosing an essential carbon store 75% of brazils emissions come from deforestation 1.5 billion tons are released due to deforestation disrupts the global carbon budget - out of equilibrium - more imput of carbon that outputs (loosing trees that sequester carbon) leads to a surplus of carbon emissions and a deficit of carbon storage

Question 30

economic impacts

Answer 30

income needed to pay of debts and improve development in the country -- eg brazil: short term jolt to the economy - new resources lure development and investment Agri-commodities are the biggest export of brazil local employment has risen - employed by tncs - but little income actually reaches them and instead either returns to the tnc home country or invested into the government - however they do gain an element of education

Question 31

social impacts

Answer 31

dilution of native culture due to increasing presence and interaction with foreign tncs - less ecosystem services 240 tribes left in the amazon and an estimated 80% of tribes have disappeared since arrival of Europeans in the 1500s

Question 32

environmental impacts

Answer 32

loss of habitat and biodiversity - less interception and roots to bind soil - more leaching of nutrients and less recycled in the nutrient cycle so less available for plant growth - evapotranspiration reduced which can drastically alter the climate as the soils and vegitation are increasingly dependent on each other to support and sustain life in the rainforest (ecological change)

Question 33

economic development - threats to the rianforest

Answer 33

increases populations wealth and access to resources which drives an increase in consumption and demand for new products which further increases deforestation (positive feedback) investment in infrastructure has lead to road developments opening up previously inaccessible areas

Question 34

human population change - threats to the rainforest

Answer 34

manaus brazil: 100,000 to 2 million by 2015 increased population pressure means the demand for resources and land space increases - places pressure on forest clearance and agri-commodities to accommodate the increase in demand monoculture cash crops have lead to mass land degradation and infertility causing more land to be cleared

Question 35

agricultural practices - threats to the rainforest

Answer 35

80% of land deforested in brazil is due to cattle ranching slash and burn could be a sustainable technique however not enough time is left between periods of burning to allow the forest to recover - land is farmed again before fertility and nutrient stores are able to recover causing degradation fragmentation of the rainforest decreases species genetic diversity and can lead to species extinction

Question 36

local rainforest management schemes

Answer 36

ecotourism - gives economic value to the forest and wildlife education: recieve education about the rainforest and subsistence farmers are given training and certification in sustainable agriculture

Question 37

international rainforest management schemes

Answer 37

tropical forest alliance 2020 - aims to reduce deforestation globally debt-for-nature swaps - reduce debts in a country in exchange for conservation of parts of the rainforest

Question 38

negatives of sustainable management schemes

Answer 38

sustainable forestry supports less local jobs than conventional forestry bring conflict over land ownership