Human Interaction with Biomes

Geography

Geoecology

Human Interaction with Biomes

Human Interaction with Biomes

• Early Settlement
• Deforestation
• Intensive Agriculture
• Industrial Activity

Figure 1: Location of biomes

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Geography

Geoecology

Topics

For this section, we will use two different biomes - Tropical Rainforest and Temperate forest biome.

See the table below for which topics fall under each case study.

Biome	Topic
Temperate Forest Biome	Early Settlement and Clearing of Forests Industrial Development
Tropical Rainforest Biome	Deforestation Intensive Agriculture

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Geography

Geoecology

Early Settlement

Temperate forest biome

• Forests of deciduous mixed woodland, such as oak and sycamore are the natural vegetation of a cool temperate climate

• These forests once covered 70% of Ireland

• Neolithic people (first farmers) began to clear the land 5,000 years ago – using the cleared land for farming and settlement

• Forest clearance increased during the Iron Age (500BC – 400AD) as the Celts had stronger, sharper tools made of iron

  • However, while deforestation increased, there was also some management of these forests

  • It was an offence, under Brehon Law, to cut down any 'nobles of the wood' – Oak, Hazel, Holly, Yew, Ash

  • Any person who damaged these trees had to pay a fine of two milk cows and one three-year old heifer

• Deforestation continued over the next 1,000 years due to Vikings and Normans constructing settlements, bridges and longboats

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Geography

Geoecology

Plantations (1500 – 1700)

• Further clearance of forests occurred to make room for the construction of roads and towns

• Plantations also saw new species of plants introduced which damaged the natural vegetation of the biome – the Rhododendron plants were brought from Asia and Spain during this time and spread into native forests in Cork and Kerry, damaging the natural woodland

• Ireland's wolf population also became extinct in the 17th Century – nearly 1,000 wolves lived in Ireland in the early part of the 17th Century with the last ever recorded sighting of a wolf coming in 1786 when it was hunted and killed

• The red squirrel has been in Ireland since before the last ice age – sightings have become increasingly rare due to the decrease in natural woodland that it lives in. The grey squirrel, introduced in 1911, also provides direct competition for food

1900's

• Only 0.5% of land was covered in woodland – 35,000 hectares

• Remnants of these forests can be seen in Killarney National Park

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Geoecology

Today

• 12% of Ireland is under coniferous woodland – the lowest in Europe

• European average is 31%

• It is hoped that by 2035, 16% of Ireland will be covered in woodland – link back to the Western Region and farmers turning to forestry

Temperate forest biome

Industrial activity effects this biome through the creation of acid rain

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Geography

Geoecology

What is Acid Rain?

• Acid rain refers to all types of precipitation (rain, snow, sleet, hail) that has a pH of less than 5.6

• Acid Rain kills or damages trees, aquatic life, crops and other vegetation, buildings and monuments

• It corrodes copper and lead piping, reduces soil fertility and cause toxic metals to leach into the underground drinking water sources

• Sulfur Dioxide and Nitrogen Oxide are the main components – produced by power stations, factories and vehicles burning fossil fuels

• These mix with water in clouds to form sulfuric and nitric acid which is then spread by winds over hundreds of kilometres

• Acidity is measured on the pH scale – 0 to 14. 0 is the most acidic with 14 being alkaline – 7 is neutral

• The strongest recorded acid rain was a similar level of acidity to lemon juice or vinegar – however it is highly damaging when it falls as acid rain

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Geoecology

Figure 3: Acid rain cycle

General Info

• Estimated that 65% of trees in the UK and over 50% of trees in Germany are affected by die-back caused by acid rain

  • Die-back is the gradual dying of plant shoots, beginning at their tips – caused by climatic conditions such as acid rain or various diseases

• Vegetation can cope with some acidic deposition

  • They can absorb some small amounts of acid rain without damage

• However, above a certain 'critical load', acid rain begins to cause environmental damage

  • In Europe, the critical load is 10-20 micrograms of sulfur per cubic metre of air – above this level, forests are damaged
  • Lichens are most vulnerable and begin to die at levels of 10 micrograms of sulfur per cubic metre of air
  • Critical levels are exceeded in many parts of Europe which has significant impacts on the environment

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Geography

Geoecology

Impacts of Acid Rain on the biome

Nutrient Leaching

• Occurs when acid rain displaces calcium, magnesium and potassium from soil particles, depriving trees of key nutrients as a result

• To combat this, lime must be added to soil in the biome to neutralise the impact of acid rain – this is very expensive as it takes 3 tonnes of lime to neutralise a field for 20 years

• Rivers also need to be limed – acid rain has damaged 11,000km and 7,500 lakes in Sweden – it has lowered the pH, killing off snails and larvae that fish and frogs feed on

Soil Germination

• Soil fertility is reduced which in turn reduces forest growth

• In Sweden, €495 million is lost each year due to acid rain affecting tree growth

• Acid rain can also damage leaves, reducing their ability to photosynthesise – damaging the trees overall health and preventing reproductive ability

Release of aluminium

• Aluminium concentrations in the soil increase with acid rain

• This causes damage to the root hairs of plants, especially trees, so that they are unable to absorb essential nutrients

• This in turn, affects the health of trees and stunts their growth

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Geoecology

Deforestation

Tropical Rainforest Biome

The felling of trees is a major problem affecting the tropical rainforest biome. Worldwide, an area of rainforest the size of Belgium is felled each year. Destruction of large areas of this biome in areas such as Brazil and Indonesia influences the global climate.

Causes

• Intensive Agriculture – requires forest to be cleared for crop growing/plantations
• Logging Companies – make profit from timber
• Construction of large dams/reservoirs
• Govt. policies
• Mining/Industry clear forest to reach minerals

Figure 4

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Geography

Geoecology

Why is it allowed?

Government Policy

• During the 1950's – 1960's, a new capital – Brasilia – was built in the heart of the Amazon rainforest to spread out settlement and exploit economic resources. Now has a population of 2.3 million people

• Large areas of forest were cleared in order to construct this city

• Further deforestation occurred on the outskirts of the city in order to house migrant workers who built the city –these people then decided to stay in Brasilia and take advantage of the greater opportunities

• Overpopulation and poverty in the 1970's/1980's created political difficulties for the government. They encouraged poor people to move to Brasilia from other cities such as Rio de Janeiro

  • Land was cleared for farms and was sometimes given away for free to entice these people out of overcrowded cities and relieve some pressure- actively promoted the destruction of forest

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Geography

Geoecology

Agricultural Development

• In Brazil, modern settlers and developers can gain ownership of land by clearing forest and placing cows on it

• This has led to uncontrolled forest burning to make new pasture

• Cash crop production is another big cause of deforestation with the need to repay international debt increasing the number of crops produced for export, such as soya bean

Economic Development

• Govt. continues to take advantage of large quantities of timber and minerals in the rainforest

• Timber companies are given rights to cut down trees and sell timber abroad with a portion of the profit made being used to repay international debt

• Illegal growing and felling of timber is also leading to rapid deforestation

• Illegal timber is estimated to account for 80% of all timber produced in the Brazilian Amazon

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Geography

Geoecology

Transport Development

• Trans-Amazonian highway stretches for 5,300km across Brazil

• This meant that large amounts of trees had to be cut down

• People were also encouraged to settle along the highway and exploit the natural resources of the forest around the road

• People were offered a 100-hectare plot of land, 6 months salary and easy access to agricultural loans in order to settle along the highway

Impact of deforestation on tropical rainforests

Rainforests are disappearing globally at a rate of 40 hectares per minute day and night. This clearance has significant impacts on people, soil and the plants and animals in the biome.

1 Impact on people

• Deforestation has had a fatal impact on native tribes – before 1500 there was 6 million native people living in Brazil. By 2000 there was less than 250,000.

• 90 tribes have been wiped out in Brazil alone

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Geography

Geoecology

• In 2011, an estimated 100 un-contacted tribes exist around the world

• There rights to land have been ignored and neglected by cattle ranchers and forest logging companies and many have been murdered for trying to resist these companies taking their land

• These workers have also spread diseases such as the common cold which have killed many tribes as they had never been exposed to this before

2 Impact on plants and animals

• Many animals and insects have not been identified yet and are becoming extinct before they can be studied

• One-quarter of all medicines come from rainforest trees. Curare comes from a tropical vine and acts as an anaesthetic

• More than 1,400 species of plants are thought to contain possible cures for cancer

• These plants, and possible cures, are being lost at an increasing rate due to high levels of deforestation

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Geography

Geoecology

Impact on soil

• The nutrient cycle is destroyed once a forest is cleared. Remaining latosol soil can be washed away by rain or baked into a hard, brick like surface due to the high temperatures. This creates laterite soil which is useless for farming and cannot support inhabitants, so they move to other areas.

• Grass growth on latosols is poor – beef cattle cannot thrive, so more land is cleared to feed them

• Deforestation can reduce the amount of carbon that the soil can absorb from the atmosphere. Within 10 years of deforestation, the amount of carbon is halved. This contributes to global warming and makes the soil less fertile

Reducing the impact of deforestation

• Agri-forestry
  • Involves combining farming with forestry
  • Farming in the rainforest comes at the expense of the rainforest
  • Agri-forestry protects the surrounding biome by integrating trees, crops and livestock on the same plot of land
  • This reduces soil erosion and promotes soil fertility

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Geography

Geoecology

Conservation zones

• Conservation zones where tree felling is banned. Brazil has many forest sites that are protected from deforestation and only used by native tribes.

Figure 5: Deforestation

Figure 6: Impact of Deforestation

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Geography

Geoecology

Intensive Agriculture

Tropical Rainforest Biome

Intensive agriculture is a type of farming whereby large amounts of crops or animal products are produced from an area of land (high yields). In order to get such high yields from the land, intensive farming uses large amounts of money, labour, artificial fertilisers, water and pesticides.

Intensive agriculture often occurs when a developing country tries to repay debts, deal with population growth or improve its economy.

Causes

• Intensive agriculture, especially the production of soya beans, completely disrupts the ecological balance of the rainforest in the following ways:
  • Large-scale slash and burn of the rainforest
  • Addition of artificial fertilisers
  • Rainforest replaced by scrub vegetation and cash crop monoculture
  • Pest infestations
  • Soil erosion

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Geography

Geoecology

1 Cattle Ranching

• Cattle ranching is the biggest cause of deforestation in the Amazon with nearly 80% of deforested areas in Brazil used for pasture

• For every quarter-pounder consumed in the USA from rainforest-produced beef, approx. 5m2 of forest must be cleared

  • MNC's, such as McDonalds, bought large areas of forest which they cleared for pasture. They did not save and sell the valuable timber from the trees that were cut down, instead they burned them in order to clear land faster

• Cattle industry has expanded rapidly since the 1970's with Brazil now having the largest commercial cattle herd in the world

• It is also the worlds leading beef exporter with the government looking to increase this further, it puts doubt on their plans to reduce deforestation

• Cattle ranching has the highest rates of slave labour in Brazil – in 2010 over 3,000 slaves were freed from cattle ranches

• The availability of cheap land means that farmers tend to abandon areas after a few years. It is cheaper to clear a fresh patch of forest than to recover pastures through the use of fertilisers. In the first year of pasture, each animal needs one hectare to support it – this rises to 2.5 after 3 years of grazing

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Geography

Geoecology

Cash Crops

• Important asset used to pay off international debts with the soya bean being especially important

• A new variety of soya bean has been developed by scientists to flourish in the rainforest biome

• Brazil is now on the verge of replacing the USA as the worlds leading exporter of soya beans

• Rainforests are typically cleared for cattle ranching and then sold on to soya bean producers two or three years later

Impacts of intensive agriculture

Large-scale slash and burn

• Forest is cut and the area burned as a method of clearing the forest

• This releases nutrients locked up in the vegetation and produces a layer of nutrient-rich material above the infertile latosol soil

• Native tribes have always used this method which has had little impact due to its small-scale

• However, large-scale intensive agriculture means hundreds of thousands of hectares are being destroyed with this method

• The plantations created are taken up with cash crops, meaning the workers have to clear even more land to grow their own food to survive

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Geography

Geoecology

Addition of fertilisers and illegal chemicals

• Fertiliser may be washed into streams, affecting fish and other aquatic life

• Pesticides are used in Soya plantations and can also pollute rivers and blow into other parts of the rainforest. This is harmful to both plant and animal life

• The illegal cultivation of coca plants is a major issue in the rainforest biome. Coca plants are the active ingredient in cocaine

• Chemicals such as sulfuric acid and acetone are used to process the leaves of the plant and are then illegally dumped, creating a huge environmental concern

• In Peru, the illegal cultivation of coca plants and subsequent dumping of chemicals in the Andes have changed annual river flood patterns

Rainforest replaced by scrub vegetation and cash crops

• When land is abandoned it reverts to scrub vegetation – the land becomes barely productive and only a small number of cattle could be grazed on it

• If the land is suitable for agriculture, then large plantations of cash crops are cultivated in single crop plantations known as monoculture – e.g soya beans, tea, coffee

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Geography

Geoecology

• These plantations are heavily mechanised which can lead to soil compaction and erosion

• In 2010, more than 62 million tonnes of soya beans were produced in Brazil on a land area the size of Britain. Animals and plants native to the rainforest biome cannot survive on these plantations so the natural ecological balance is disrupted or destroyed

Figure 7: Effect of clearing land for intensive agriculture