P1 tropical rainforests Flashcards
where are tropical rainforests found ?
- cover 2% of the earths surface
- home to half of the worlds plants and animals
- found in a broad belt close to the equator from south America in the west
- through west Africa to southeast Asia and Australia in the east
what are the 5 physical characteristics of tropical rainforests
-climate
- water
- soil
- people
- plants and animals
Describe the climate in a tropical rainforest
- tropical rainforests thrive in the equatorial climate, experiencing high temperatures (27 deg)
- high rainfall throughout the year (2000 mm per year)
- creates ideal growing conditions and accounts for the lush vegetation growth
how is water a physical characteristic of a tropical rainforest
- experience a distinct wet season
- high rainfall lasting months
- excess water on the ground, swelling local rivers and sometimes causing flooding
- water will soak into the soil, dissolving and transporting away nutrients-> called leaching
Describe the soils in tropical rainforests
- rainforest soils are not very fertile
- nutrients are very concentrated in the upper topsoil and are quickly taken up by plants as they grow
- in response, trees have shallow roots to maximise their use of these vital nutrients
- intense leaching removes nutrients from the topsoil and redeposits them further down
how are people a physical characteristic of a tropical rainforest
- traditional tribes living in rainforests live in harmony with the natural environment.
- hunting and gathering only what they need to survive
- this is a sustainable system
- increasingly people are exploiting the rainforests for commercial gain
- chopping down trees for timber or to make way for ranching or commercial plantations
- extremally harmful to the rainforest ecosystem as habitats are destroyed
how are plants and animals a physical characteristic of a tropical rainforest
- rainforest have the highest level of biodiversity in the world
- there are thousands of species of plants and animals
- birds live in the canopy high above the forest floor, feeding on seeds and nectar from flowing plants
- mammals, such as monkeys and sloths are well adapted to love in the trees
- snakes use the trunks of trees as vertices highways from the forest floor to the canopy above
- animals such as deer and rodents browse on vegetation from the forest floor
how is the tropical rainforest interdependent
- the tropical rainforest ecosystem is a fragile environment
- it is easily damaged by peoples activities and can take a long time to recover
- its survival depends on a close interdependence between its complex parts
- if one component is removed e.g trees are removed through deforestation - harmful knock on effects will threaten the survival of the entire ecosystem
what is nutrient cycling
- the vast majority of nutrients are stored in the biomass
- the soil contains few nutrients, as any nutrients released by decomposers are quickly absorbed by the trees and plants or leached into the soil by heavy rainfall
- there are few nutrients in the litter store, as decomposers, thriving in the warm and wet conditions, quickly break down dead leaved and branches
- there are rapid transfers of nutrients indicated by thick arrows. this is hugely to do with climate conditions; for example warm and wet conditions promote chemical weathering
what are plant adaptations
- the vegetation, and animals, are well adapted to the climate conditions experienced within each layer
- access to sunshine is a key factor promoting strong vertical growth, as shown by the emergent trees punching through the canopy exploiting maximum sunlight
- lianas grow around and between the tree trunks to get as much light as possible for growth
- drip tips help get the water that is intercepted by the canopy to the forest floor where it can infiltrate soils
- buttress roots helps to anchor the trees to the shallow forest floor
what are animal adaptations
-due to the intense competition for food, animals have become adapted to live of specific plants or animals that few others eat. for example toucan and parrots have strong beaks for cracking hard nuts
- bats thrive of the fruits growing in the canopy, which they can reach by flying, they also help to disperse seeds
- animals also use colour to act as a camouflage or to warn predators e.g poison dart frog
- three toed sloth to help them crawl up trees where they live the majority of time
why are there high levels of biodiversity in rainforests
- wet and warm climate encourages a wide range of plants and trees to grow, providing many habitats for animals
- the rapid recycling of nutrients speeds up plant growth (producers) and provides food fir consumers
- many parts of tropical rainforests are untouched by people, enabling a range of plants and animals to thrive
what are the threats to biodiversity in tropical rainforests
- with the exception of natural events such as lightening strikes(fires), floods, and disease, the greatest threats come from people
- unsustainable timber harvesting
- development of roads and settlements
- slash and burn agriculture, creating commercial plantations
what are the main issues associated with biodiversity decline
keystone species: a species that has multiple connections with other species. as it a multiple food source, there could be serious knock on effects if its number decline.
-indigenous tribes being unable to survive in rainforest and having to abandon there traditional lifestyle
- plant and animal species may become extinct
- important medical plants may become extinct
how is the rate of deforestation changing in the amazon rainforest
- despite the previously high levels of deforestation, from 2004 deforestation has reduced significantly
- the main reason is the action plan implemented by the Brazilian government in 2004
- however since the change in Brazil’s government in 2019 there has been renewed deforestation in the amazon and rates are set to increase rapidly
- scientists are concerned about a potential ‘carbon bomb’ if the burning continues
what are the 6 causes of deforestation in the amazon rainforest
- subsistence farming and commercial farming
- logging
- road building
- mineral extraction
- energy development
- settlement and population growth
how is subsistence farming and commercial farming a cause of deforestation in the amazon rainforest
- indigenous rainforest tribes practise subsistence farming
- recently land has been cleared for commercial farming
- in Brazil, cattle ranching account for 80% of deforestation
- soy beans, palm oil and sugar cane (for biofuel) are the major crops