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Tropical Rainforests - Coggle Diagram

- - - - function
        
        vital services provided could be significantly impacted by hotter, drier conditions
        
        less vegetation cover means that when it does rain, surface runoff will increase because of a reduction in infiltration. more sediment will be carried into drainage systems, polluting water quality. increased silt in rivers harms some freshwater fish species
        
        the TRF ecosystem influences precipitation because of the vast amounts of water vapour that are pumped out by the extensive vegetation. less dense forest means lower rainfall in surrounding areas
        
        TRF on mountains is known as 'cloud forest' - these forests have a function called 'cloud stripping' where they soak up moisture from passing clouds. the slow release of this water into the drainage system provides areas downstream with a steady supply of water all year - drier conditions would stop this
        
        drier forest emits more CO2 than it absorbs and if dry forest burns in forest fires, the adds even more CO2 in huge amounts. droughts in the Amazon TRF in 2005 and 2010 are estimated to have each added 5 billion tonnes of CO2 into the atmosphere
      - biodiversity
        
        TRF plant species cannot tolerate drier conditions and are unable to survive prolonged drought or forest fires. temps in TRF ecosystems are very similar all year round and species cannot cope with fluctuations
        
        as conditions become drier and warmer, other plant species suited to the new conditions would spread and out-compete TRF species. this may also include the spread of pests and diseases that TRF species are not immune to
        
        some biodiversity may be able to be preserved if species would be able to migrate to higher areas - temp drops by 1 degree every 100m, so TRF of hills and mountains would not hear up so much
      - structure
        
        vegetation cover is likely to change to seasonal tropical forest (similar to that in more wooded areas or tropical grasslands) - happens when the dry season starts to last for several months
        
        most trees drop their leaves in the dry season to avoid water loss through transpiration
        
        no canopy in the dry season and thick underbrush can grow among the tress
        
        lack of vegetation in the dry season means animals are adapted to live on stored food or go into a sort of hibernation - biodiversity still high, but much lower then in the TRF
        
        trees have deep roots to reach groundwater (no buttresses) or are adapted to store water
        
        falling leaves make a deep litter layer, but decomposition is very slow in the dry season so the soil becomes a bigger store of nutrients and the biomass store is smaller
  - - - resource extraction. resources can be extracted from the rainforest areas. some countries have sold the rights to minerals in the rainforest or sold rainforest timber as a way of raising money to help with development. the forest is then often cleared for large-scale mining operations including access roads and settlements where the workers live.
      - population pressure. due to overpopulation, there is pressure to clear areas of the rainforest in order to make space for people to live. the number of people living near rainforests has increased due to promises of work in new energy, resource extraction and agriculture in the area. as the town expands, rainforest is cleared to make room and favelas also stretch into areas that used to be rainforest.
      - agriculture. much of deforestation is due to want for land for farming or cattle. many believe the soils must be rich to support the lush vegetation. one type of this is tavy, which is a type of 'slash and burn' agriculture. trees are cut down on a small plot and the undergrowth burned, adding nutrients to the soil which will last a few years, and then crops are planted. the nutrients in the soil are quickly exhausted and weed growth takes over. at this point the farmer often decides to clear another plot
  - - - 7000 medicinal drugs can be extracted from rainforest biodiversity
        
        oxygen - 'earth's lungs'
        
        timber
        
        help provide a clean water supply by preventing soil erosion and encouraging infiltration
        
        source of food and livelihood for locals
    - - maintain and protect biodiversity
        
        store CO2 in soil and plant life - climate change buffer
        
        attract tourists and can be used for recreation
        
        dense rainforest can stop floods from happening - canopy prevents soil erosion, vegetation reduces surface runoff that could cause flooding
        
        attached to native people's cultures and ways of life
  - - - government policies (governance) - most rainforest in Madagascar is owned by the government. twenty years ago the Madagascan government set up a scheme for local communities to manage their own resources sustainably. international advice was that sustainable rainforest management would only succeed if local people were in charge. one successful project is Association Mitsinjo. locals and groups are vital to make sure that the forest is not exploited and resources are used sustainably
      - ecotourism - in some areas, locals have created a group of guides who take tourists around reserves. this brings in income, while allowing guides to patrol the reserves to look out for illegal logging and snares for animals. this has been successful in preventing illegal logging and hunting. this brings in money, allowing people to have an income that does not damage the rainforest
      - industry co-operation - this is very important as agriculture is a main cause of deforestation and large companies benefit from this. by getting companies to cooperate, this can bring large-scale benefits as companies often have a large impact. this can help discourage deforestation. companies can be encouraged to do this as it gives them good publicity
      - services - Association Mitsinjo manages a rainforest restoration project in which farmers get help with improving their crop yields and in return agree to set aside some of their land as a nursery for growing young rainforest trees. more than 1m trees have been planted from 150 local species. by improving crop yields, more food is grown and there is no need to clear more land, so less deforestation happens as well.
- - - - abiotic - non-living
        
        TRFs have very poor soil quality - low in nutrients
        
        warm temperatures and moist conditions are perfect for the chemical weathering of the bedrock, which releases minerals into the soil. however, TRF soils are often 30 or 40m deep, so these nutrients do not reach the upper layers. the constant rainfall means that a lot of water travels down through TRF soils. as it trickles through the soil. the water takes nutrients and mineral salts with it - leaching. Leaching makes TRF soils low in nutrients
        
        hot, damp conditions on the forest floor allow for the rapid decomposition of dead plant material
        
        climate - hot + wet, temp range between 27-30 degrees C, with lots of rainfall as well.
        
        climate supports huge biodiversity -> intense competition means that nutrients never stay in the soils for long/have time to accumulate
      - biotic - living
        
        nutrient cycle diagram is the key to understanding the TRF ecosystem. the biggest store is biomass (B), which is all the living things in the TRF(biotic characteristics). when leaves fall or branches drop into the litter store (L), they decompose very quickly. as soon as the nutrients are released into the soil, the plants of the TRF hoover them up. the trees have shallow roots because the only fertile part of TRF soils is a very thin nutrient layer right at the surface. the nutrient cycle returns nutrients to the biomass store very quickly
        
        humans play an important role in many TRF ecosystems - people hunt animals for food, spread the seeds of rainforest plants through the fruits, nuts and seeds that they eat, and affect the ecosystem through their use of fure
      - the nutrient cycle
        
        describes how nutrients are transferred around an ecosystem. Gersmehl used a model based on nutrient cycles to explain differences between ecosystems. Gersmhel's model said all ecosystems have the same 3 basic compartments: soil, litter and biomass and each is a store of nutrients and nutrients are transferred between stores.
        
        rainforest nutrient cycle (use textbook):
      - other characteristics:
        
        although rainforest trees are deciduous, different species lose their leaves at different times and only for a few weeks, so the forest always looks green
        
        trees grow very tall - 30-40m, but although very tall, have very shallow roots
        
        stratification - the rainforest has different layers - forest floor / shrub / understorey / canopy / emergent
        
        equatorial - climate is hot and wet - humid. as sun is directly overhead receives lots of heat. warm air at equator rises, as it rises it cools and condenses leading to cloud formation, as clouds form moisture is released as rainfall this is why it is wet
        
        no seasonal variation - temp and precipitation constant throughout the year
        
        soils - latosoils - not fertile. high competition from plant life means any nutrients are consumed immediately. high water content means nutrients are transported out of soils as water sinks underground - leaching
      - e.g. question + MS
        
        Assess the role of biotic and abiotic characteristics in the functioning of tropical rainforests.
        
        AO2
        
        The nutrient cycle involves the movement of nutrients (e.g. phosphates, nitrates) between the physical environment and living organisms.
        
        Nutrient cycling in the tropical rainforest is very rapid.
        
        Many of the soils are old and impoverished and are low in nutrients.
        
        The hot, damp conditions on the forest floor allow for the rapid decomposition of dead plant material.
        
        This provides plentiful nutrients that are easily absorbed by plant roots.
        
        However, these nutrients are in high demand from the rainforests many growing plants.
        
        The nutrients do not remain in the soil for long. They stay close to the surface in the soil.
        
        The thick layer of leaf litter and decomposing organic matter is rapidly broken down by decomposers (bacteria, fungi, termites) which take up the nutrients and release them as wastes when the organisms die.
        
        The plants are able to take up the released nutrients in their roots.
        
        The dense vegetation cover helps to protect the nutrients from leaching.
        
        Human activity is impacting on nutrient cycling (e.g. through deforestation).
        
        AO3
        
        • Naturally, the key is the rapid decomposition of dead organic matter.
        
        • This is clearly linked to climate.
        
        • The hot, wet climate causes rapid decomposition of the leaf litter.
        
        • It also provides heat and water to support the rapid growth of vegetation.
        
        • Other factors also affect the rate of nutrient cycling.
        
        • Human impact has a considerable effect through deforestation - the removal of ground cover lead to the leaching of nutrients (washed out of the soil be heavy rainfall) and to their removal from the cycle when crops are harvested.
        
        • The impact of human activity is accentuated by the fact that the soils are relatively nutrient poor and rely on rapid cycling for their fertility.
        
        • Evaluation may depend on the location of examples used.