8a - Tropical Rainforests Flashcards
What are the typical locations and climate of TRFs?
- mainly located 10 degrees S, close to equator
- unevenly distributed and mainly inland
- rains throughout the year (highest in Jan, lowest in July)
- little temp variation (27-30) & never below 20 degrees all year
- little seasonal variation
What are the main characteristics of TRF?
- has a layered structure/stratified
- have very tall trees
- straight & narrow trunks
- very dense vegetation growth
- buttress roots (big roots supporting trunks), lack of ground cover & lianas
Why is there a high biodiversity in the TRF?
- hot/wet tropical climate is ideal for vegetation growth
- complex stratification of rainforest creates a wide range of ecological niches
- many parts are isolated, untouched so biodiversity unaffected by human activity
What are plant adaptations in TRF?
- drip tips remove excess water in conditions of over 2m precipitation
- buttress roots stabilise very tall, thin trees
- wavy leaves stop water infiltrating the leaf and rotting it
- tall straight tree trunks grow straight up towards the light to out compete other species
- epiphytes sink roots into a host plant so don’t need to sink roots to the ground
What are animal adaptations in TRF?
- many are camouflage mimicking sticks & leaves making them hard to see eg big cats have camouflaged fur and are adept at climbing to catch pray
- primates have grip hands & prehensile tails for balance & colour vision for ripe fruit
- birds have loud calls which is easier to hear than see in the dense canopy
Describe the rainforest nutrient cycle
- Bigger biomass store as high biodiversity means more nutrients held in vegetation & more photosynthesis means more available nutrients
- smaller soil store since nutrient uptake is faster due to the number of plants & more rainfall causes leaching so nutrients are washed from the soil
- smaller litter store in TRF due to high humidity so higher rates of decomposition
How could climate change lead to ecosystem stress in TRF?
- weather systems shift polewards reducing rainfall in TRF
- TRF gets hotter -> drought
- no vegetation growth so CO2 emitted but not absorbed
- CO2 released by forest fired & they cause leaf litter organisms to die so nutrients can’t break down
- canopy dries, letting rain through which leaches soil
- food supply dries up
Ecosystem stress
What are tropical rainforests threatened by directly and indirectly?
Directly:
deforestation due to :
- commercial hardwood logging,
- commercial & subsistence agriculture
- local demand for fuel wood and biofuels
- local demand for mineral resources & electricity/HEP
Indirectly:
Climate change leading to drought and ecosystem stress
How are TRF threatened by agriculture?
Commercial agriculture:
- deforestation for cattle farming, sugarcane, biofuels, palm oil plantations (in everything)
- crops grown for exports -> mono-culture leaches soil out of certain nutrients
Subsistence agriculture:
- growing enough food to feed families
- they start with a small plot, burn the undergrowth, plant crops & nutrients leach out so let ground recover
- this process continues but plots are being reused quicker and nutrients aren’t recovering
How are TRF threatened by mining and HEP?
Mining:
- open cast mining is economically efficient but uses large areas of TRFs
- mining often extracts charcoal which helps the country develop
HEP:
- dams produce huge reservoirs which flood the forest
- electricity used for ion ore and bauxite mines
- both construction of dams and mines cause damage
How are TRF threatened by commercial hardwood logging and biofuels?
Commercial hardwood:
- demand for furniture and exports help pay international debt
- gov has strict controls but difficult to enforce as rural poverty is high and illegal logging pays well
Biofuels:
- used to make biodiesel
- plantations means you have to burn down rainforest
- destroying carbon sink
What is REDD?
Aims:
- reduce emissions
- conserve & enhance forest carbon stocks
- sustainably manage forests
How:
- TNCs fund projects to conserve forests or funds come from the World Bank
- remote sensing used to monitor deforestation rates
- idea to offset CO2 emissions and therefore meet emission reduction
What are advantages and disadvantages of REDD?
Pros:
- provides international expertise from many NGOs and govs
- top down approach means forested areas in entire countries are protected which limits local shifts to nearby forests
- provides local developing communities with viable alternative income which acts as incentives to stop current practices
Challenges:
- corruption may occur at top-end during gov to gov funding
- difficult to monitor all local actions as funding may not reach all communities
- we still need rainforest products as demand is still there and is likely to outweigh need for developing countries to reduce emissions
- REDD is vague about what counts as replanted forest - funding may be used for replacement with oil palm trees
What is CITES?
- stops cross-border trade of endangered animals
- adopted by 181 countries
- targets 34000 endangered species
What are benefits and challenges of CITES?
Benefits:
- 181 countries have signed up and international trade has been limited
- species are protected
- some big success since ivory trade has declines
Challenges:
- protecting species, not ecosystems which doesn’t prevent deforestation so could harm species
- countries have to set up and fund their own monitoring/policing systems & poorer countries cant afford this
- hard to monitor all countries
- species have to be under threat but this could be too late
State some reasons as to why deforestation rates vary?
Rising due to:
- poverty
- foreign debt
- economic development
Reducing due to:
- gov policies
- international condemnation
- monitoring systems
What are positives of ecotourism?
- preserves natural areas which are seen as an economic resource
- more forests leads to more tourists as they want to see protected land
- land protected from farming, logging, mining
- encourages individual conservation
- embraced locals for jobs/involvement
- multiplier effect on other parts of the economy - donation, flights, bus rides, hotels, food
What are negatives of ecotourism?
- profit may be the focus so you try get too many people there so environment becomes more fragile
- hard to detect logging due to inadequate enforcement
- jobs can be low paid
- profits may return to developed countries running the projects
- hard to find upward mobility - jobs progression
How can sustainable farming help protect TRF?
- agroforestry (trees & crops planted at same time) so tree roots bind the soil & leaves protect from heavy rain
- intercropping helps protect soil from erosion
- allows subsistence and small scale commercial agriculture
- however more difficult to farm in this way
What are the challenges of achieving sustainable forest management?
Sustainable forest management is when a forest is used in a way that prevents long-term damage whilst allowing people to benefit from the provided resources
Challnges:
- economic benefits only seen in LT & poorer countries need income now
- provides fewer jobs than conventional forestry causing some to turn to illegal logging
- sustainable forestry unlikely to provide enough resources to match increasing demand
