Threats to the tropical rainforest - deforestation
The tropical rainforests of the Amazon Basin face the threat of deforestationThe cutting down of trees and forests to allow a different land use.. Deforestation is happening for the following reasons:
- Farming - large areas are cleared for pastoral farmingWhen animals are reared, eg cows for their meat.. As the global demand for meat has increased, many cattle farms have opened in the Amazon Basin for beef farming. arable farmingWhen crops are grown. is also responsible for the loss of tropical rainforests as many farmers are clearing land to grow cash cropCrops which are sold for profit., such as soya beans, often in monocultureGrowing one type of crop. plantations.
- Logging - tropical rainforests are cut down so that valuable trees like mahogany can be accessed and sold for timber to make furniture. Other trees are cut down for making paper products.
- Mining - the Amazon Basin is rich in natural resources such as iron ore, copper, tin, aluminium, manganese and gold. This has led to the development of mines which results in the clearance of tropical rainforest. The Carajas mine in Brazil is the world's largest iron ore mine.
- Roads - the construction of access roads for farmers, loggers and miners results in large parts of the tropical rainforest being destroyed.
- hydroelectric power (HEP)Energy generated from fast-flowing water. - The creation of HEP stations in the Amazon Basin has resulted in large areas of forest being flooded to create the reservoirs and dams. The flooding of the Balbina dam in Brazil resulted in the loss of 920 square miles of tropical rainforest.
- Population - population growth has resulted in the loss of tropical rainforest as land is cleared for subsistence farmingWhen people only grow enough food to feed themselves and their family.slash and burnAn agricultural process where plants are chopped down and then burnt. farming, or to build houses and infrastructureThe basic structures needed for an area to function, for example roads and communications. .
- Tourism - camps and lodges are being built to satisfy the demands of increased 'eco-tourism' visitors.
Impacts of tropical rainforest loss
The impacts of the deforestation of the Amazon Basin include the following.
Soil erosion
Once the land is cleared of rainforest vegetation the soil is left bare. When it rains, the nutrients in the soil are washed away. The nutrient cycleCyclic movements of nutrients such as calcium, potassium and magnesium within an ecosystem. stops because there are no plants or trees shedding leaves to replace the nutrients in the soil. The soil is no longer able to support plant life because it is not fertile. The roots of plants and trees no longer hold the soil together so it is easily eroded.
Loss of biodiversity
Many different species of plants and animals die because of deforestation. As plants and animals are closely connected through the food webA network of food chains, showing how they all link together., deforestation this reduces the biodiversityThe range of animals and plants in a given area. , or variety of species found in the tropical rainforest.
Climate change
The trees and plants of the Amazon Basin absorb carbon dioxide during the process of photosynthesisA chemical process used by plants to make glucose and oxygen from carbon dioxide and water, using light energy. Oxygen is produced as a by-product of photosynthesis. Algae subsumed within plants and some bacteria are also photosynthetic.. If there are fewer trees and plants, due to deforestation, then less carbon dioxide is removed from the atmosphere. In this way deforestation contributes to global warmingThe rise in the average temperature of the Earth's surface. and therefore climate changeThe long-term alteration of weather patterns..
Economic development
The creation of mines, farms and roads - which caused deforestation - has also led to economic development. The money created from these enterprises allows a country to generate foreign income, which can then be used to pay off debts or be invested in further development projects.