Posts tagged geography

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What are Tropical Rainforests? How can we stop them being destroyed? What causes this loss of biodiversity?

      Tropical Rainforests are characterised by hot, wet climates and are distributed mainly along equatorial areas such as Brazil, North-East Australia and Mexico. Temperatures are high and constant throughout the year because the sun is always high in the sky. The annual temperature range is <3^oC inland and 1^oC on the coast. Mean monthly temperatures vary from 26 ^oC-28 ^oC.  Total annual rainfall usually exceeds 2000mm and most afternoons have a heavy shower. The climate encourages year-round vigorous plant growth. Despite the favourable conditions, there is strong competition for light which has resulted in the stratified structure of plants and trees. Some trees for example have very few branches so that they are able to grow alongside other trees clear of the canopy to gain the most light, these are known as Emergents. Whilst trees may vary in height, all are evergreen because any tree that remained dormant for part of the year could not compete with the constantly growing evergreens.

      The way in which plants and animals have adapted along with the climate makes Tropical Rainforests the most biologically diverse ecosystems in the world. It is estimated that they contain over 50% of the world’s species in only 7% of the world’s land. They are of great importance  not only in terms of their richness of life, but also act as Many raw materials used in industry and subsistence use such as charcoal, gums, resins and oils, pulpwood, plywood and veneer, and medicines. Subsistence refers to the use of natural products of the environment to support oneself, where the person will only take as much as they need with none or very little waste generated. Tribes indigenous to the rainforest practice subsistence farming, harvesting and gathering. However, it is not just the native people who use the rainforest; it has also attracted much interest from multi-national companies and other industry.

      The most well-known of the Rainforests in the Rainforest biome is perhaps the Amazon Rainforest that covers much of Brazil, Bolivia and Peru in South America. It is about 5.5 Million square km and it represents over half of the planet’s remaining rainforests. The Amazon in particular has been deforested since its colonisation by Europeans in the 16th century, although the rate of deforestation has rapidly accelerated in the last decade as the result of various government policies, logging companies, agriculture and increased interest in biofuels. 

      Tropical rainforests are being destroyed at a rate of 11 million hectares a year and have become scattered and fragmented.  The main reasons for deforestation in the Amazon are government projects such as the Avanca Brazil project and activity of foreign companies. The Avanca Brazil project was launched in 2000 to accelerate economic development in Brazil, particularly in agriculture, timber, mining and employment. The government wanted to use the land of the Amazon for the project to generate national income to pay off foreign debts and deal with the issues of a rising population.

       A rising population creates a greater need for housing and more living space. The Government planned to use the land of the rainforest to build homes to house the growing population and prevent overcrowding in cities such as Rio di Janeiro and Sao Paolo. The project also generated jobs in logging, mining, construction and farming, lowering the unemployment rate. This would then have a knock-on effect for the local and national economy as people will then be able to buy good with their wages and stimulate the economy. The new industry was also meant to create foreign investment and increased exports. These exports include soya, timber and coal.

      Soya, exported by companies like Cargill and other multinational companies, has become more popular in recent years because it makes a good, inexpensive chicken feed and is frequently used to feed chickens reared for sale in fast food restaurants such as KFC and McDonalds. It was thought that the increased investment from foreign companies would sustain a flow of cash to improve facilities in Brazil such as roads and highways, gas lines, hydroelectric projects, power lines and river channelization projects.

      Commercial logging is the second biggest cause of rainforest destruction; most of the timber taken from the forest is exported to richer countries. It is used in the construction industry and for making furniture, plywood, veneers, wood pulp and paper. Trees may even be cut down simply to gain access to other, rarer hardwood trees such as mahogany. In other areas, trees may be cut down simply to clear land for grazing and for mining, but also for hydro-electric power projects and road building project to improve transport of products for export.

      Many companies such as Cargill and worldwide fast food chains such as McDonalds stand to gain from human intervention in the Amazon Rainforest; however, there are significant costs for the ecosystem.  Deforestation is such a big problem for the rainforest because fewer trees due to deforestation results in less humus, which then leads to less nutrients being added to the soil, with some lost through leaching also. Soil then becomes infertile and produces poor quality vegetation and soil erosion occurs, meaning fewer trees and leaves can survive and it becomes a cycle. This loss of vegetation that comes as a result of deforestation is not just a loss of biodiversity in itself, but it also leads to a greater loss of biodiversity as the trees and the canopy structure are habitat to many species of insect, small mammals and other organisms.

      Even if an animal’s habitat is not directly lost, its movement may be altered by fragmentation and islandisation within the forest, disrupting feeding and mating patterns. This may then have an impact on the animal populations, resulting in a decrease in biodiversity. Also, the Amazon is still largely unexplored, and it is believed that there are many species of plants and animals inhabiting it that have yet to be discovered, but some may well have been lost already by the effects of human intervention in the Amazon. That is why it is so important for it to be protected.

      Sustainable projects in the Amazon Rainforest include ecotourism, rubber tapping and extraction of non-timber forest products. Ecotourism focuses on educating tourists to the Amazon about preserving the natural environment and using it sustainably, for example, they may stay in cabins and be guided through the forest by local tour guides. The emphasis is on providing a cultural experience where they may go to visit tribes or go to see places on interest within the forest. Ecotourism has been relatively popular and provided the local economy with jobs and wages to spend locally, often providing or supporting further industry.

      Another sustainable project has been set up by the organisation responsible for the protection of the Amazon rainforest, IBAMA. They are having the government of Brazil continually create new ecological reserves that will protect the rainforest and its biodiversity from damage. It will also create wide ecological corridors that allow animals to move freely between reserves so that they are not isolated by the fragmentation and islandisation of the forest. These ecological reserves and corridors are protected land that cannot be deforested or exploited, and so it goes some way to attempting to preserve the habitats of the organisms of the forest, and the hope is that it will also preserve much of the biodiversity of the rainforest.

      Rubber tapping and extraction of non-timber products are sustainable projects because they do not damage the tree and are more traditional activities that local people had previously engaged in before the moving in of multinational companies. Rubber tapping and fibre, honey, fruit, nut and medicinal plant collecting are making a return though, with local people employed for the projects. They are incredibly successful, with the fruits of the Acai palm used to make a mineral rich wine being the most important non-wood forest product in terms of income for the Amazon. Medicinal plants are sustainably extracted, without causing unnecessary damage, to make 2/3 of mass produced drugs.

      Sustainable projects in the Amazon have been successful; however, deforestation is still occurring on a massive scale, which may not be able to be counteracted by the projects. It may be that more focus will need to be put upon reducing deforestation by multinational companies, although it does bring in investment to improve infrastructure and quality of life for the Brazilian people. More legislation could be put in place by the Brazilian government such as insisting that for every tree felled, two are planted in its place, and the planting of desirable trees to prevent the practice of needlessly cutting down trees to gain access to few rarer species.  However, the forest is important for the whole word, and perhaps more should be done by countries other than Brazil if we are to preserve the rich biodiversity of the rainforest.

Indicators tend to fall into one of three categories: qualitative, quantitative and composite. 

Indicators can also be categorised as demographic, economic, social, environmental and political (and composite again!)

Demographic indicators (Quantitative): Include things that are telling about population (age-sex) structure e.g. life expectancy, population density. 

Economic indicators(Quantitative): Measures in terms of how developed the economy is, using factors such as GDP (Gross Domestic Product) and levels/percentages of poverty (usually defined as people living on less than $1-$1.25 per day).

Social indicators (Quantitative): Attempts to measure quality of life instatistics such as adult literacy rate (%) and calorie intake per day.

Environmental indicators (Quantitative): Measures environmental quality using for example carbon dioxide emissions. Be careful when considering this as a measure of development, as it can vary from less developed to more developed countries. In some cases emissions will depend on population size, unless of course measured per capita (per person). Some NICs or RICs may have higher emissions, although to be higher per capita is unlikely. 

Political Indicators (Quantitative): Again, uses statistics as a measure of wellbeing, may include rates of homicide, ratio of men to women in politics etc. This again should be taken with caution considering that political indicators depend upon both culture AND development, particularly where women’s rights are concerned. 

Composite Indicators: These combine a number of different factors (e.g. political, economic) and will often use qualitative as well as quantitative to attempt to provide a fuller picture of development.