When one thinks of the Amazonian rain forest, it is very unlikely that paved roads and highways will come to the imagination. Unfortunately, in the past 35 years road construction has been the main reason for the deforestation in Brazil's Amazon basin. In an effort to expand its frontiers and develop economically the impenetrable areas of the country, Brazil's government has launched a series of projects aimed at improving the infrastructure in the Amazon region. This included mainly the building of big transport arteries such as the Trans- Amazon highway and the subsidizing of small-scale farming along those arteries. The National Development Plans (NDP's) did not meet their initial goals since few people settled in the newly expanded areas and those who settled still suffered from low income, lack of educational opportunities and low life expectancy.1
The negative impact on the environment of the planned human expansion is tremendous. It has been estimated that 10 million hectares of the Amazon forest have been destroyed due to clear-cutting, burning, slash-and-burn agriculture and conversion to pastures. Deforestation is caused mainly by road construction since 74% of the converted areas is within 50 km of roads.1 This clearly shows that frontier expansion and colonization for economical and social reasons has a devastating effect on the environment. The Brazilian Amazon is the largest piece of undisturbed rain forest and, unfortunately, this natural treasure is being damaged very carelessly and at an extremely high rate.
Despite the above grim conclusions, the Brazilian government persists in its effort to expand the infrastructure by appropriating more and more land from the heart of the Amazon basin. In 1999, the government started a new program, called Avança Brazil (Forward Brazil), which intends to add 6,245 km of paved highways and 1,600 km of railroads to the existing transportation network. The highlights of the project include the construction of the Santarem-Cuiaba and Porto Velho-Manaus highways, which would traverse pristine forest areas.1
There is a heated debate about the effects on the environment of the new construction project. Researchers and environmentalists predict that "Avança Brazil" will cause deforestation at a rate between 269,000 and 506,000 hectares per year. They also accuse the Brazilian government in negligence and corruption, because "Avança Brazil" was approved without the necessary environmental assessment reports from the Ministry of the Environment.2 Government officials claim that measures have been taken to minimize the negative impact on the environment, but do not present facts and examples of how this is being done. The government emphasizes more on the social rather than on the environmental aspect of "Avança Brazil". It claims that the project would improve the lifestyle of 20 million people, who are now completely cut off from civilizations and live in extreme poverty.3
The construction of roads leads to a variety of human activities with a detrimental effect on rain forest ecosystems. First of all, large areas need to be deforested so that the actual highways could be built. The second biggest problem after deforestation is fragmenting of undisturbed areas. The loss of integrity of the rain forest results in loss of biodiversity. When the natural habitat of a species is being reduced to a smaller area and that area is easily accessible by humans, the species has a bigger change of going extinct. After the advance of colonization, a primary rain forest is almost certainly doomed to perish. Easy access to new lands encourages forest-destructive activities such as logging, slash-and-burn agriculture and intentional fires.
It is obvious that economic development and infrastructure expansion bring irreversible damage to tropical rain forests. However, there are ways in which the negative impact on the environment could be significantly reduced. It is very important that development plans such as "Avança Brazil" include efficient land zoning projects as well. Road construction should be accompanied by intensive, not extensive land use. Also, the government should closely monitor and control the frontier expansion so that illegal logging and slash-and-burn agriculture are kept to a minimum. In theory, Brazil has an impressive legal system for the protection of the environment, but in practice, these laws are not enforced. That's why the government has to take measures to prevent the overexploitation of the newly developed areas. There are also financial incentives such as "carbon-offset" funds to encourage developing countries like Brazil to conserve forest areas. Since the burning of one hectare of forest, releases around 200 metric tons of CO2-equivalent carbon, developed countries are ready to subsidize developing countries under the condition that they would minimize carbon-release in the environment.2
Economic development and forest conservation are not mutually exclusive terms. Generally, human expansion into areas with great ecological importance has negative impact on the environment, but this impact could be reduced by enforcing legislation and controlling the rate of expansion. Road construction should be subjected to a very careful planning and the use of the surrounding land should be optimized. Therefore, the best recipe to conserve the environment is to exercise travel and frontier expansion with moderation.
1. Carvalho, G., Nepstad, D., McGrath, D., Diaz, M., Santilli, M., and A. Barros. 2002."Frontier Expansion in the Amazon: Balancing Development and Sustainability" Environment 44: 34-45.
2. Laurance, W., Cochrane, M., Bergen, S., Fearnside, P., Delamonica, P., Barber, C., D'Angelo, S., and T. Fernandes. 2001. "The Future of the Brazilian Amazon" Science 291: 438-9.
3. Silveira, J.P. 2001. "Development of the Brazilian Amazon" Science 292: 1651-2.
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