Another major factor for the loss of biodiversity is Hydroelectric power (HEP). This is because in order to construct HEP stations, large areas are needed and thus, the most ideal places for these stations are in the tropics due to the immense amounts of land and the easy access to water. And hence, in order for HEP stations to be built, vast amounts of land in the tropics are cleared directly linking the construction to deforestation and hence the loss of biodiversity. The most archetypal example for this would be the construction of the Tucurui Dam situated in the Amazon region in Brazil. The Tucuri Dam is the 4th largest dam in the world and it produced electricity for approximately 40 million people. However, during the construction of the dam, double the size of Hong Kong was flooded and 14,000 people were relocated by the government. 3,750 of these people moved to new islands created by the reservoir which lack adequate infrastructure. Not to mention, the deforestation and the construction of the dam is directly to blame for the loss of biodiversity such as the habitat destruction of unique fish, animals and plant species such as the Dorada and the Picuda. In addition to this, some of the other serious effects include deforestation (leading to increased CO2 emissions and biodiversity loss), change in water quality (affecting fauna, flora and human populations downstream), the breeding of disease bearing mosquitoes (enabling the spread of disease), and the contribution to the green house effect due to the construction of the dam reservoirs.
As mentioned in the introduction, another factor that affects the loss of biodiversity is migration. As populations continue to rise, room for residential areas in the city continue to diminish and thus people have to seek new areas to reside in. Hence, the tropics become a very desirable area for residing in due to the vast amounts of space triggering deforestation as extensive areas of the forest are cut in order to make room for the growing populations. In addition to this residing in forests is also a very beneficial idea for this people as it provides them with job opportunities such as farming on deforested land, logging, cattle ranching and so on. One such example would be the situation in Dak Lak, Vietnam. In present conditions, the local authorities in Dak Lak were expressing their concern over the high influx of people to the area due to need of space as well as for the need of finding and occupations through cutting down trees in the rainforest. There were 186 new households or 821 immigrants in 2006, and 67 new households with 312 immigrants in the first quarter of 2007. According to statistics from the Dak Lak Forest Management Department, nearly 100ha of forest have been occupied for cultivation and at least 20ha of forest have been cut down by immigrants this year. Similar to the paragraphs above, some of the effects of migration include deforestation which first and foremost leads to the loss of biodiversity. In addition to this, deforestation also leads to increase carbon dioxide emissions, soil degradation and infertile soil (due to affected nutrient cycle) and a much drier climate due to less evotranspiration.
Last but not least, an additional cause for the loss of biodiversity is logging. Logging can be defined as the the process in which certain trees are cut down by a lumberjack or machine. This process of logging can be directly linked to that of deforestation as trees are being constantly cut down. Furthermore as only certain trees are being cut down, logging could also directly lead to the potential extinction of certain trees. For instance, in the northern part of the Amazon, the tropical hardwood in the name of Roxinho was greatly exploited in the form of logging. The first tree was cut two months ago but by now, the part of the Amazon available for logging is slated to swell to more than six times its current size. Researches estimate this to have a drastic effect on the Amazon and on us humans as well considering the fact that in the next five years, Brazil plans to sell logging rights to more than 27 million acres of jungle leaving these areas prone to logging. Some of the effects of logging firstly includes the loss of biodiversity as habitats are being destroyed and thus many plants, animals and organisms lost. Not to mention due to elimination of the trees there are elevated levels of carbon dioxide, degraded and infertile soil due to the manipulations explained below. As trees are constantly being cut down the nutrient cycle is gravely affected. This is because as the availability of the trees lessen there is firstly less oxygen, less moisture in air and less evotranspiration. In addition to this, since there are no leaves, no litter is returned to the ground (no organic matter). This therefore means that there is no humus replaced and thus fewer nutrients returned to the soil and fewer nutrients for plant use. Not to mention, as there aren’t any leaves intercepting the rainfall, the soil is prone to leaching where its minerals and nutrients are washed away by the run off leaving the soil infertile and degraded due to the presence of iron and aluminum.
Thus in conclusion, the most major causes for the loss of biodiversity include globalization & cattle ranching, hydroelectric power, migration and logging. All the causes are directly linked to deforestation and the effects of these causes include the loss of biodiversity, increased levels of carbon dioxide emissions, increased levels of methane gas, soil degradation, manipulations to the nutrient cycle, displacement, floods, change in water quality, the breeding of disease bearing mosquitoes and the contribution to the green house effect due to the construction of the dam reservoirs.
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Here's what a teacher thought of this essay
A very good examination of the causes of biodiversity loss in tropical rainforests which incorporates a number of appropriate examples. Structure is good, however at times it seems like the effects are tagged on the end of the paragraphs. 4 stars