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The Amazon Basin Manaus Brasilia Paragominas Carajas Rondonia
Matte Grosso
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Amazonia Climate Hot and wet all year – 27 degrees Celsius average temperature. Rain all year, in excess of 250mm per month, annually up to 2000 mm. Small diurnal (daily) temperature range of 5-6 degrees convectional rainfall small annual temperature range (2-3 degrees) no seasons as a result of temperatures and rainfall. Convectional Rainfall Sun heats ground, ground heats air, water evaporates, warm air rises, as it rises it cools, condenses to form clouds, clouds become saturated, it rains. High temperatures due to angle of the sun and latitude: The earth’s axis is at 23.5 degrees, effecting the angle at which the sun’s rays strike the Earth. At the equator, the sun is directly overhead twice every year, in March and September (equinoxes). This means that the incoming rays of sunshine are concentrated over a smaller area, so more of the sun’s energy reaches earth, rather than being lost when passing through the atmosphere. This accounts for the high temperatures and low temperature range. Cloud cover means that diurnal range of temperature is low.
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The Amazon Rainforest Adaptations of Plants
5 layers in the forest: Undergrowth – very little because there is little light Layer of shrubs and young trees Discontinuous under canopy of smaller and immature trees Continuous layer of the main canopy formed by crowns of many tall trees Discontinuous canopy of tree crowns of the tallest trees, called emergent trees. Adaptations of Plants Drip tip leaves – sheds water quickly so that leaves do not rot Branchless tree trunks – trees save their energy to grow to be as tall as possible to reach light. Lianas – vine like plants climb the tree to reach the sunlight Shallow roots – because all of the nutrients are found at the surface of the soil Little undergrowth – little light available makes it difficult to survive Waxy cuticle (leaf surface) protects leaf from intense sunlight and rain Buttress Roots help to support the tall tree Tall trees – grow to be as tall as they can to allow them to reach maximum amount of sunlight.
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Nutrient Cycle Soils This means This means that... that...
Sunshine and rain help the trees to grow. Trees contain nutrients. Leaves fall to the ground and rot, making nutrient rich humus. Rain washes nutrients from humus into the soil. Nutrients are contained in the soil, which are absorbed by plant roots. When trees are chopped own, the nutrient cycle is broken, which puts the forest in danger. Climate: Hot throughout year, very high precipitation, no seasons, daily heavy rainfall Vegetation: Very dense evergreen forest, huge biodiversity, constant growing season Soils This means that... This means that... Leaching occurs – soil is washed of nutrients There is a constant layer of material like leaves which decompose adding to nutrients in the soil Soil is POOR Soil is RICHER Overall, soils are poor, nutrients are washed away by rain and drained of nutrients by the huge numbers of vegetation.
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Agriculture Cattle ranching – Mato Grosso
Shifting Cultivation – ‘Slash and Burn’ The indigenous Amerindian tribes such as the Yanomami practise this type of subsistence agriculture. It is sustainable, as it works with the ecosystem. A small area of forest is cleared using machetes, and when the felled trees have dried out, they are burned. The ash produced helps to provide extra nutrients for the soil. Holes are made in the ground, and cuttings and seeds of crops like sweet potatoes, cassava, manioc and bananas are planted. Hot wet climate means crop grow quickly, but must be weeded regularly. Crops are harvested. After 3 or 4 years, crop yields decline as soils lose nutrients, and the tribe move to another area, leaving this for 30 years to allow it to recover. Shifting cultivation pros: works with ecosystem, sustainable, traditional, does not harm biodiversity. Cons: low yield, limited crops, supports only small numbers of people. Peasant Farming - Rondonia Non-indigenous people who have arrived in the Amazon through government encouragement. Many poor people from the East of Brazil move land on the sides of roads. However, as more forest is cleared, the soil loses nutrients and farmers’ yields decline, and so they can no longer live off the land. This results in most moving to the city to look for work. Pros: new life, support form government, reduces overpopulation elsewhere, improves accessibility. Cons: Clears large areas of forest, soil is poor, so poor yield, will not support people for long. Cattle ranching – Mato Grosso From 1970 onwards, many transnational companies set up large ranches on which to keep cattle to produce beef. Each animal requires a large area of land form grazing, and is provided by cutting down trees in the forest. Soil fertility rapidly reduces and grazing becomes too poor for ranching.
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Exploitation of the Forest: Case Studies
Paragominas – Logging South of Belem, is the most extensively logged area of the Amazon, where illegal logging is a problem. Carajas – Mining On the Tocantins River, 900km SW of Sau Luis, a deep water port, where open cast iron ore mining takes place. Current excavations are 4.1 km long, 300m wide and 400m deep in 14m high, step like benches. Electricity supply from Tucurui HEP station used for powering living quarters and machinery Belem Highway and Trans-Amazonian Highway pass through Carajas. 900km rail corridor cleared holding 25 pig iron smelters using charcoal. Producing the charcoal deforests 6000km squared per year. 2160km squared flooded to provide dam with water. Cattle ranching - Mato Grosso Largest area of deforestation for cattle ranching. 1.5 cows supported per hectare, because grass is so poor. 2 cowboys look after 1000 cows, so employment is low. Carajas – Mining On the Tocantins River, 900km SW of Sau Luis, a deep water port, where open cast iron ore mining takes place. Current excavations are 4.1 km long, 300m wide and 400m deep in 14m high, step like benches.
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Effects of Exploitation
Use of the forest Effects on people Effects on environment Logging Provides an alternative source of employment, improves accessibility into the forest, there is a high demand for hard wood, which means that the locals will get a good price for selling it. Tree fall gaps allow rain to reach soil and wash away nutrients. Roads have to be cleared for access. Skids are created by tractors. Log decks needed to store felled trees so more land must be cleared. Unmanaged, so unsustainable. Hardwood is very scare e.g. mahogany, so felling these trees is wasteful Cattle Ranching Little employment because few cowboys manage large numbers of cattle. Many transnational companies own the ranches, so profit goes out of the country. Deforestation because of land clearance for ranch and roads, fertile soils destroyed. Mining Mineral deposits in the Amazon include bauxite (the main constituent of aluminium), iron ore, manganese, gold, silver and diamonds. Minerals can be sold for high profits. This can be reinvested into infrastructure. Provides an alternative source of employment. Destroys forest – loss of habitat and biodiversity. Can cause air pollution, and water pollution in the mining of gold etc. Power source is often charcoal, so more trees used to provide this. Lots of forest cleared for roads and railways.
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Ecotourism “Tourism based around the ecological and human resources of an area. This includes scenic landscapes, traditional cultures and heritage. It means small visitor numbers, sustainable use of resources, responsible travel and conservation of the environment.” The World Tourism Organisation believes that ecotourism has a role to play in conservation and the reduction of poverty in traditional communities in remote regions. It is the opposite of mass tourism, e.g. Package holidays. Ecotourism groups have a ‘Green Globe’ to show that they have fulfilled all criteria. Sustainable Tourism must: Preserve biological diversity Minimise ecological, cultural and social impact Maximise economic benefit to local communities Alta Floresta Tourist Project, Mato Grosso Alta Floresta is a town in the highlands of the Amazon rainforest, home to an innovative research centre and ecotourism centre. It was set up to study sustainable uses of the forest and to teach people in the area how to use the forest responsibly. The money raised at Alta Floresta is used for: Educate tourists on rainforest ecology Raising awareness of importance of conservation Support the research centre in protection of natural habitats and endangered species Building schools and hospitals Educating farmers Local people can work at the centre so they have good employment. The centre can be accessed by boat only, so no forest is cleared to make roads.
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