Download 2009 Q18 biomes altered human activity

Leaving Certificate Geography Geo-Ecology
Higher Level 2009 Q 18
Q: Assess how biomes have been altered by human activity. (80
marks)
From studying Geo-ecology, I have learned that biomes have been altered by human
activity. These include early settlement and clearance of forests, industrial development,
felling of tropical rain forests and intensive agricultural practices.
1. Early Settlement and Clearance of Forests
In the temperate forest biome of Ireland, Irish land was deciduous mixed woodland growing
undisturbed.
About 7,000 years ago during the Neolithic times farmers first arrived in Ireland. They
farmed lighter, grittier soils in the uplands. When the Celts arrived in 500BC, they brought
their iron tools with them. They efficiently farmed the land by clearing only what they
needed for settlement and farming. They farmed and grazed animals in the west of Ireland
which lead to overgrazing the land and forced the soils to be exposed for example, the
Burren in County Clare of exposed limestone bedrock. Deforestation also continued as the
Vikings and the Normans made use of the forests in Ireland for building their boats, bridges
and destructive settlements.
In the 16th century, English and Scottish settlers arrived and cleared the forests to a greater
extent. They tilled and cut down the old ancient forestry to make more room for farming,
towns and roads. By 1921 at the end of the British rule less than 1% of Ireland was covered
in forest. These forests are in Kenmare in County Kerry and Lough Gill in County Sligo.
This lead to a great amount of animals distinct to the biome being extinct, for example the
Irish elk and wolf.
2. Industrial Development in Europe
Manufacturing industry can damage biomes in many ways. These range from the creation of
acid rain and an increase in air and water pollution.
Industrial activity in Europe is the main cause of acid rain. It is formed when emissions,
such as sulfur dioxide that is released from fossil fuels, mix with rainwater forming a weak
sulfuric acid. This rain then falls as rain with a pH less than 5.6, making acidic soil.
There are many effects of acid rain on vegetation. It can cause leaf damage that reduces it's
ability to photosynthesize. It leaves the plant vulnerable and weak. Seed germination (the
growing of seeds) is reduced. Alluminium levels in the soil increase due to acidic rain. I t
damages the tree's root hairs which affects the absorption of nutrients. In an effort to
overcome these problems alkaline lime from limestone is added to bring the soil back to
neutral after acid rain. I t is an expensive job as it takes 3 tonnes of lime to neutralize a field
for 20 years.
There are also effects of acid rain on animal life. For example, it has raised the pH of
Sweden's waterways, killing off snails and larvae that feed frogs and fish there. Fish also die
from alluminium poisoning due to being in the water. Acid rain has also killed millions of
woodland animals in Europe.
3. Felling of Tropical Rain Forests
In the Amazon rainforest in Brazil, deforestation is occurring at an alarming rate. This
Equatorial biome provides high temperatures and plentiful rainfall all through the year. The
forest is dense and luxuriant and it's trees form an almost continuous canopy over the land.
Slash and burn cultivation refers to when people remove the vegetation layer by hand and
then burn the left over scrub vegetation that wasn’t of any use to them. After it's burned the
land is ploughed that returns the charred nutrients back to the ground to act as a fertilizer.
Originally in the tropical rainforest, the natural native people like the Yanomani tribe
practiced "slash and burn" and small areas of land were cleared for subsistence farming
(growing enough to feed themselves). After some time the land was exhausted and the
people moved on but due to the small size of the land, the forest took it over again and made
it as good as new. This is called sustainable exploitation of the forest as it is managed well,
causing very little harm to the forest biome.
Deforestation is the clearance of forests. These clearances have normally been done by
people outside the biome such as Europeans. Less than 2% of the natural rainforest along
Brazil's Atlantic coast has survived. The tropical rainforest has decreased from 2.9 billion
hectares to 1.5 billion hectares today.
Logging is the process of cutting down trees and exporting them to make a profit. As Brazil
is a rapidly developing country and economy, it uses it's mineral rich trees and as a result
the government gets a portion of the timber profits. However, 80% of all timber logging
activities are illegally done in the Brazilian rainforest to make outputs such as cheap
plywood.
Mining is another cause of felling tropical trees. Iron ore and copper are mixed in the
rainforest which need hectares of cleared land to extract them.
Much felling is carried out to provide settlement for Brazilians. Cleared land was given to
poor settlers to build flavellas on due to overcrowding. Between the 1950's and 1960's the
Brazilian government began building a new capital Brasilia in the rainforest, mainly to
attract more people inland away from the overcrowded coastal cities. Today, 2.3 million
people live in Brasilia, almost treble the population of Dublin.
Reducing biodiversity is then a growing concern to the biome. It refers to the variety of
plant and animal life in a biome. Unsustainable exploitation of the forest is an ongoing thing
as 2,000 mature mahogany trees are cut down every minute. In this biome, tropical trees are
home to 15 million species of plants and animals.
4. Intensive Agricultural Practices in Brazil
Intensive agriculture needs the highest yield from the land. Some effects are related to
farming, soil erosion and plant and animal habitats and indigenous people.
Farming is ongoing in the biome. Deforestation of the tropical rain forests has made way for
large cattle ranches and soya bean cultivation. These are mainly farmed by large multinational companies. Soils can be damaged due to the use of fertilizers and pesticides to kill
all bugs around which throws the entire ecosystem out of balance, harming plants and
animals. Now the Brazilian government encourages larger-scale clearances for agriculture
as 40 hectares of rainforests are lost every minute to agriculture use. If this continues, it's
estimated by 2050 only 40% of Brazil's rainforests will be left.
Soil erosion is caused by the removal of the tree canopy (top layer of tree leaves). It can be
in a case of 2-3 years a soil can lose it's fertility as it is deprived of it's foliage layer leading
to a lack of humus. It is now called laterite soil as it has been baked in the sun and is useless
to men. To prevent the cattle from starving, more land is felled to feed them as part of the
vicious cycle.
In the Brazilian biome, small habitats have been destroyed to the extinction of some animals
and species for example the Panther, a large solitary black cat native to this biome. One
quarter of all pharmaceutical drugs originated from the rainforest biome, such as Asprin
from the cinchona tree for malaria. If the biome goes on to be destroyed, scientists wont be
able to discover the plant species and cures for many of our diseases such as cancer and
AIDS.
The Indigenous people have suffered due to intensive agricultural practices. In Brazil, 90
tribes have been wiped out due to industrial and agricultural spread into the biome. Most
were wiped out by diseases brought by man such as the Europeans to which they had no
immunity, for example the common cold. The number of native tribes people in the region
as been reduced to less than 250,000 in 2000 from nearly 6 million in the 1500's.
In conclusion, biomes can be altered by human activity. In the Brazilian rain forest, the
human activities such as early settlement, and the clearance of forests, industrial
development in Europe, the felling of tropical rain forests and the intensive agricultural
practices in Brazil have all helped to damage the ecosystems in the world’s forests.