Geography 7.3.1 Tropical Rainforest
All parts of the tropical rainforest (TRF) ecosystem are interdependent
A change in one part affects others
Deforestation leads to the loss of habitats and reduction in biodiversity
Loss of trees also impacts the nutrient cycle
The interdependence of the rainforest components means that when one element is affected it then impacts all the other components
A decline in one species (especially if it is a keystone species) can lead to a decline in other species
The Zam tree produces seeds which are food for agouti and who disperse the seeds
The agouti is hunted for meat, reducing their populations, which means fewer seeds are dispersed
Fewer new Zam trees will germinate and so there is less food for leaf cutter ants, which in turn means less food for the tree frogs and the snakes which prey on the frogs
The Zam tree is pollinated by a particular species of butterfly. Without the flowers the numbers of the butterfly species will decline: this also affects the beetles which lay their eggs in the butterfly faeces
Plant and animal species may become extinct: this may happen to some before they are even discovered
Important medicinal plants may become extinct
Indigenous communities may be forced to abandon their traditional lifestyle due to the lack of food to hunt and gather
The TRF has five distinct layers
Ground layer (0m)
Shrub layer (3-4m)
Under canopy (15m)
Canopy (30m)
Emergents (45-55m)
Typical structure of a tropical rainforest
The plants and animals within the tropical rainforest are very well adapted to the climate conditions
Adaptations of Plants and Animals in a TRF
Plants | Animals |
Waxy leaves with drip tips: these ensure that rainwater runs off the leaf and does not remain which would encourage mould growth or break the leaf | Sloth: algae grow in the fur of the sloth helping to camouflage it |
Buttress roots: these large roots above the ground which help to support the very tall trees because the roots below the surface are shallow | Toucan: they have a large bill to reach and cut fruit from the branches of trees. They are also strong allowing them to crack nuts open |
Lianas: vines which use the tall trees as support to reach the sunlight | Primates: they have prehensile tails to help them climb trees |
Epiphytes: these are plants which grow on trunks and branches of trees getting nutrients from air, rain or debris accumulating around the plant | Geckos: they have large, flattened toe pads with sticky scales which allow them to grip the smooth tree trunks |
Straight, smooth trunks: help to reduce the number of epiphytes using the tree | Stick Insects: Their stick and leave shapes help them to be camouflaged |
TRFs have some of the highest levels of biodiversity of any ecosystem
The wet and warm climate means there is year round growth
Wide variety of plants provides a range of habitats and food
Rapid nutrient cycling increases plant growth
Lack of human activity in the past has meant that plants and animals are undisturbed
TRFs have a continual growing season with high rainfall and temperatures all year round
The nutrient cycle is rapid
Trees and plants lose their leaves all year round
The high level of moisture and high temperatures leads to rapid decomposition and recycling of nutrients
Plants grow quickly which leads to a rapid uptake of nutrients from the soil
Most of the nutrients are stored in the biomass
Few nutrients are stored in the soil and the litter
Tropical rainforest nutrient cycle
The result of this rapid nutrient cycle is that the soil in the TRF is not very fertile
Net Primary Productivity (NPP) is higher in the rainforest
As in all ecosystems the TRF has a complex food web which includes
Producers
Primary consumers
Secondary consumers
Tertiary consumers
Tropical rainforest food web
All parts of the tropical rainforest (TRF) ecosystem are interdependent
A change in one part affects others
Deforestation leads to the loss of habitats and reduction in biodiversity
Loss of trees also impacts the nutrient cycle
The interdependence of the rainforest components means that when one element is affected it then impacts all the other components
A decline in one species (especially if it is a keystone species) can lead to a decline in other species
The Zam tree produces seeds which are food for agouti and who disperse the seeds
The agouti is hunted for meat, reducing their populations, which means fewer seeds are dispersed
Fewer new Zam trees will germinate and so there is less food for leaf cutter ants, which in turn means less food for the tree frogs and the snakes which prey on the frogs
The Zam tree is pollinated by a particular species of butterfly. Without the flowers the numbers of the butterfly species will decline: this also affects the beetles which lay their eggs in the butterfly faeces
Plant and animal species may become extinct: this may happen to some before they are even discovered
Important medicinal plants may become extinct
Indigenous communities may be forced to abandon their traditional lifestyle due to the lack of food to hunt and gather
The TRF has five distinct layers
Ground layer (0m)
Shrub layer (3-4m)
Under canopy (15m)
Canopy (30m)
Emergents (45-55m)
Typical structure of a tropical rainforest
The plants and animals within the tropical rainforest are very well adapted to the climate conditions
Adaptations of Plants and Animals in a TRF
Plants | Animals |
Waxy leaves with drip tips: these ensure that rainwater runs off the leaf and does not remain which would encourage mould growth or break the leaf | Sloth: algae grow in the fur of the sloth helping to camouflage it |
Buttress roots: these large roots above the ground which help to support the very tall trees because the roots below the surface are shallow | Toucan: they have a large bill to reach and cut fruit from the branches of trees. They are also strong allowing them to crack nuts open |
Lianas: vines which use the tall trees as support to reach the sunlight | Primates: they have prehensile tails to help them climb trees |
Epiphytes: these are plants which grow on trunks and branches of trees getting nutrients from air, rain or debris accumulating around the plant | Geckos: they have large, flattened toe pads with sticky scales which allow them to grip the smooth tree trunks |
Straight, smooth trunks: help to reduce the number of epiphytes using the tree | Stick Insects: Their stick and leave shapes help them to be camouflaged |
TRFs have some of the highest levels of biodiversity of any ecosystem
The wet and warm climate means there is year round growth
Wide variety of plants provides a range of habitats and food
Rapid nutrient cycling increases plant growth
Lack of human activity in the past has meant that plants and animals are undisturbed
TRFs have a continual growing season with high rainfall and temperatures all year round
The nutrient cycle is rapid
Trees and plants lose their leaves all year round
The high level of moisture and high temperatures leads to rapid decomposition and recycling of nutrients
Plants grow quickly which leads to a rapid uptake of nutrients from the soil
Most of the nutrients are stored in the biomass
Few nutrients are stored in the soil and the litter
Tropical rainforest nutrient cycle
The result of this rapid nutrient cycle is that the soil in the TRF is not very fertile
Net Primary Productivity (NPP) is higher in the rainforest
As in all ecosystems the TRF has a complex food web which includes
Producers
Primary consumers
Secondary consumers
Tertiary consumers
Tropical rainforest food web
