Geoecology Essay- Effect of Human Activity on a Biome

Assess how biomes have been altered by human activity

For the purpose of this question I will examine the Tropical Rainforest Biome and how it has been altered by human activities. Humans have had a massive impact on this biome and I will examine it under the headings of deforestation, intensive agriculture and the need for settlements areas.

Deforestation

There are various reasons why humans cut rainforests, however in Brazil it has been happening at an alarming rate since 1970. Trees are a renewable resource but in the Tropical Rainforest Biome not enough time is being given to allow to rainforest to grow back. The Brazilian Government is prepared to open up the 'Lungs of the Earth'in order to take advantage of the tropical hardwoods that grow in this biome and the mineral wealth that lies underneath the forest. Timber companies have been given the rights to remove forest and sell timber abroad. Tropical hardwoods such as teak and mahogany fetch huge profits abroad. The government of Brazil takes a percentage of these profits. However, illegal companies also operate, selling cheap supplies of plywood accounts for 80% of all timber produced. As the area is rich in resources, licences were given to mining companies o clear forests and mine for metals such as iron ore and copper. Experts estimate that 137 plant, animals and micro-organisms will be destroyed from this biome in the coming years due to deforestation. 40% of the rainforest will have disappeared. Natural habitats are being wiped out for plants and animal species, as well as the environment damage deforestation causes.

Intensive Agriculture

The Amazon covers 1 billion acres taking in countries like Brazil and Peru. 80% of the world's diet can grow in the Amazon like coconuts, oranges, bananas, rice, sugar and coffee. The opinion of the Brazilian government is that the rainforest is an economic resource and should be used to develop the economy. The demand in the Western World for cheap meat is met by Brazil's willingness to encourage MNC's to locate there to farm intensively or set up ranches. Ranches can slash and burn acres of rainforest and seed it with grass for cattle while receiving tax credits and loans from the government. Soya plantations are now becoming more of a threat than cattle ranches. Companies like McDonald's grow soya beans on acres of land that were once covered by forest. As a result the latosols of the Tropical Rainforest Biome are damaged by the agrochemicals and mechanisation levels to soil erosion. The roots of the trees that bind the soil together are gone and the heavy convectional rain washes the soil into the Amazon River. Soya is a plant not native to this biome and threatens the habitat as GMO's can invade the natural environment. The expansion of intensive agriculture (soya plantations) in Brazil is contributing to the loss of 40 hectare of rainforest every minute of every day. When a forest is cleared, the nutrient cycle is destroyed. The remaining soil can be easily washed away by heavy rain. In addition, as a result of the high temperatures in this region, the exposed soil is baked into a hard, brick-like surface, which cannot support plant growth. This is known as a laterite soil, which is useless for farming. The grass growth on the laterite is so poor that the beef cattle do not thrive and even more land is cleared to feed them.

Need for Settlement

A new capital, Brasilia, was built form scratch in the heart of the Amazon rainforest in the 50's as Brazil gained freedom from Portugal. This was to encourage the settlement of the region. Today it has a population of 2.3 million. To construct this city, large areas of forest were cleared. More deforestation occurred on the outskirts of the city where small, temporary housing settlements were built for the migrant workers who moved to this area in order to construct the new capital. Instead of returning to their original homes on completion of the city, these workers chose to stay and avail of the greater opportunities in Brasilia. An unlimited water supply and ideal river conditions led to the development of many HEP stations to support the growing settlements in the Amazon. Over 125 new HEP dams have been built in the Brazilian rainforest area. One example is the Tucuri Dam, which caused over 2500km  of rainforest to be flooded. More than 8000 people lost their homes and thousands of animals died. The Trans-Amazonian highway, a 5300km road, was built across Brazil from east to west to facilitate settlement in the Amazon basin and also to allow the movement of people and goods through previously inaccessible areas. This affects the emissions from all the cars using the road and many animals native to the biome were killed as the motorway crosses their natural habitat. In January 2000, the Brazilian government announced its plan for Avanca Brazil. This is a €30 billion plan to cover much of the Amazon rainforest with 10000km of highways, hydroelectric dams, power lines, mines, gas and oilfields, canals, ports, logging concessions and other industrial developments. All of the above has resulted in the loss of many species of plants, and this is a serious concern as some contain chemicals that could one day cure serious illnesses. About one quarter of the medicines we use come from rainforest plants eg. aspirin. The Tropical Rainforest Biome is a carbon sink meaning that the trees take in carbon from the air and store it and use it to create oxygen. Today as carbon emissions around the world rise, the loss of vast amounts of trees in the rainforest will contribute to climate change. By burning the forest to create land, more carbon is also released into the atmosphere.