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Location: The Amazon Rainforest, Brazil, an LEDC in South America What the case study shows: The structure, climate, vegetation, uses, damage to and management of an ecosystem Location: Tropical rainforests are located on near the equator. Usually between 25 degrees north and south of the equator. The equatorial rainforests are; The Amazon- South America, Congo/ ZaireAfrica; Indonesia- Asia. Causes of damage by people: Logging –expensive trees sold to MEDCs to make furniture. Population increase – new settlements and roads are built for Brazil’s growing population. Cattle Ranches – land is sold, trees are cut down so cattle can graze on shrub layer. Food sold to MEDCs Minerals – expensive minerals like iron are mined and sold to pay off Brazil’s debt. Hydro-electric power (HEP) – dams are built so HEP can be generated to power Brazil’s growing population & industry. CALLED DEFORESTATION Vegetation Soil: No seasons so flowers, fruit and seeds available all year. 4 layers Emergents – highest trees 45m Canopy – Thickest layer 30m Under canopy – 15m Shrub – 5m Trees have thick buttress roots due to thin soil. Soil poor as nutrients quickly removed by trees. Dead vegetation quickly decayed so plenty of nutrients on top soil. Nutrient Cycle: Most nutrients in the tropical rainforest are in the plants and trees. When the plants/ trees/ leaves die then these nutrients are broken down and replaced back into the soil by decomposers (fungi). These nutrients can be taken up again by other fast growing plants. This is a continuous cycle. Water cycle: The sun heats up the earth. By 9 o’clock it is 25 degrees. By midday it is 30 degrees. Evaporation occurs (changing of a liquid to a gas). This gas cools and condenses to form thick black clouds. This leads to afternoon thunderstorms (heavy precipitation) everyday. By early evening the precipitation has stopped and the sun goes down. Plants protect the soil from heavy rainfall (Interception) and decrease the surface runoff and infiltration rates. This happens every day. This is a continuous cycle. Preventing deforestation: Sustainable Forestry Replant any trees cut down. (reforestation). Replant trees in layers- mimics the rainforest (Agroforestry). Selective logging where most trees are left standing. (only cut down the trees that are needed- that way soil remains protected) Create a national park zone- no deforestation can take place. Create demand for wood from sustainable forests. Money Eco- tourism- money used from tourist to conserve rainforest. People are taught to conserve. Reduce debt owed to foreign governments if rainforest is conserved. Laws Ban the sale of wood from unsustainable forests. Ban deforestation. Protect rainforest with police and wardens. Deforestation&Vegetation Cutting down trees stops nutrients reaching soil as there are no leafs. Heavy rain then washes thin soil away. Strong winds blow the soil away. Where soil remains the nutrients get washed down through the soil (leached). Soil becomes infertile so little tree growth. Deforestation & nutrient cycle Trees cut down. Therefore there is no leaf fall. As there is no leaf fall decomposers have no job to do and nutrients are not replaced back into the soil to be used by other trees. Eventually the soil will become infertile. Deforestation & the Water Cycle Trees are cut down so less evapotranspiration. Fewer trees so less interception of rainfall and increased surface runoff. Less infiltration means more surface runoff of rain water. More surface run off leads to soil erosion as there are less tree roots to bind the thin layer of soil together. This causes floods and landslides. Rivers blocked with soil which causes floods. Climate: High temperature all year of around 26oC. This means a continual growing season. Very high rainfall of 2000mm a year. Rain is convectional due to high temperature. Rain falls all year. Rainfall is high as pressure in this area is low- this means that air is rising therefore condensation is occurring therefore there are clouds and rain. It is very hot because it is fairly close to the equator therefore the sun has a shorter distance to travel. This means that less heat is lost, so it warmer. Also the surface area is smaller- heat is more concentrated. Location: Alaska inside the Arctic Circle in the Northern Hemisphere and Antarctica inside the Antarctic Circle in the Southern Hemisphere What the case study shows: the threats to the tundra cold environment of Alaska and the polar cold environment of Antarctica & how the threats are managed. Climate Graph Threats to the environment in Alaska Threats to the environment in Antarctica The fragile tundra environment is at huge risk The last great wilderness on earth, a polar cold from oil spills. environment, is under threat from a variety of factors. Oil exploitation – Alaska is the biggest oil producing state in the USA. Oil is extracted and Tourism – around 23000 tourists visited then transported 1200km from Prudhoe Bay in Antarctica in 2008. The tourists land on north Alaska to the terminal of Valdez in the Antarctica by small boat and cause south by the Trans Alaskan Pipeline. environmental damage. In 2006 1m litres of oil leaked from a corroded Mining – huge deposits of oil are under the ice pipe at Prudhoe Bay polluting an area covered and the rising price of oil would make it in rare grass and home to Caribou. economically possible to extract it. Oil is transported out of Valdez by oil tanker. Global Warming – as well as melting ice, global warming also causes krill (the main producer in In 1989 the Exxon Valdez tanker ran aground in the food chain) to die. This means that the Prince William Sound releasing 42m litres of oil primary and secondary consumers further up the into the sea. 390000 seabirds, 300 seals, 250 food chain are under threat as there is less food. bald eagles & 22 killer whales died. Fishermen lost their jobs. Science – there are a huge amount of scientific research bases in Antarctica which produce a The US government wants to open up new huge amount of waste. oilfields in the Arctic National Wildlife Refuge. Reasons for the cold and dry climate How the threats are managed in Alaska How the threats are managed in Antarctica 1. Latitude – Alaska and Antarctica are where the Land Use Restrictions – the Arctic National The Antarctic Treaty was signed in 1991 by the sun’s rays cover large parts of the curve of the Petroleum Reserve is an area where any oil world’s most powerful countries t keep earth. This means that the heat is spread out drilling can take place and people can use the Antarctica as a natural reserve devoted to peace over a wider area and the sun’s rays have to pass area recreationally (fishing, hunting etc). In the and science and place where all activities must through a large amount of atmosphere. The sun’s 1002 Area companies can search for oil, but are have a limited impact on the environment. rays lose heat. not YET allowed to drill for it. People are not Tourism – the International Association of 2. Antarctica is colder than Alaska because of its allowed to use the area. People and oil Antarctic Tour Operators has formed and agreed permanent ice cover as ice reflects heat rather companies are banned from the Arctic National to promote responsible tourism to keep the than absorbs it. Wilderness Area. wilderness (which attracts the people in the first 3. Antarctica is colder than Alaska because of its Renewable Energy – developing a sustainable place) in tact. altitude (height). source of renewable energy is the only way to Mining – All mining is banned for the next 50 4. Antarctica is colder than Alaska because its manage the tension between the global years. interior is a greater distance from the warm economy needing oil to keep us wealthy and Science – Most waste is taken away from the ocean. also protect the environment. Wind power, continent, but sewage and food waste is 5. Antarctica is colder than Alaska because of its tidal power, solar power are all examples. biologically treated and then burnt. Experiments cold katabatic winds flowing over the cold ice with using renewable energy to power the from the South Pole to the edge of the continent. research bases are starting. Location: The Sahel Africa What the case study shows: The climate, causes of desertification and solutions to desertification in the Sahel. Location: On or above the Tropic of cancer and the Tropic of Capricorn. Climate: The climate here is very hot all year. Rainfall is low as pressure in this area is highthis means that air is sinking so no clouds or rain. It is very hot because it is fairly close to the equator therefore the sun has a shorter distance to travel. This means that less heat is lost, so it warmer. Also the surface area is smallerheat is more concentrated. Causes of Desertification Climate change - Many years of drought and average rain has been decreasing. Farming - Declining death rates have caused populations to increase more food and resources are needed and fragile areas have to be farmed. Overgrazing - Increase in the numbers of cattle etc has removed vegetation. Irrigation - Pumping of water from underground to water means tree roots can no longer reach water. Deforestation - Trees have been cut down for fuel and building materials. Erosion - When vegetation is removed, soil is no longer held together by roots - soil is eroded by wind and by water in the wet season. Vegetation Soil: Desert plants are adaptive plants are built to store water, find water quickly or live with the littlest amount of water possible: Boabab Tree – fat trunk, no leaves, deep roots, thorns. Acacia Tree – deep tap roots, high leaves, thorns. Cactus Tree – thick trunk, no leaves, deep roots, spiky. Desert soils are often salty because whatever little rain that does fall quickly evaporates from the ground, leaving salt and other minerals behind. Soils often have abundant nutrients because they need only water to become very productive Nutrient Cycle: Most nutrients in the desert are in the plants and trees. When the plants/ trees/ leaves die then these nutrients are broken down and replaced back into the soil by decomposers (fungi). These nutrients can be taken up again by other fast growing plants. This is a continuous cycle. Soils and have little or no organic matter. Water cycle: Rainfall in the desert often totals a few inches yearly or, in some regions, there is absolutely none. When rain does happen it happens because the intense heat in the day evaporates whatever moisture there is in the soil or on surfaces vegetation. Evapotranspiration occurs. This gas cools and condenses causing clouds and rain. Evaporation rates regularly exceed rainfall rates. Sometimes rain starts falling and evaporates before reaching the ground. Vegetation intercepts the rain and rain infiltrates the soil and is quickly taken up by plant roots. Very little remains in the soil. Effect on people How damage affects vegetation How damage affects How damage affects water cycle When vegetation is removed the soil has nutrient cycle Heavy rainfall, such as a flash flood 1000s die due to starvation. no protection from the sun or the wind. Trees cut down. Therefore increases the amount of surface run 1000s fall ill due to It quickly dries out in the hot sun & is there is decomposition to off. As the land is hard and dry, the malnutrition. easily blown away by the wind. Without occur. Nutrients are not rain cannot infiltrate the hard soil and 1000s fall ill due to drinking vegetation the plant roots that bind the replaced back into the soil flows quickly overland, carrying the dirty water. soil together are removed. Soil can be to be used by other trees. soil away with it. People move to the cities to easily blown away by the wind. Nothing Eventually the soil will get away from the problems can grow in the soil. become infertile. adding to the problems of overcrowding. Management of desertification: Reafforestation = the replanting of trees that can grow in the climate. This will help to bind the soil together and aid the nutrient cycle. Coppicing = encouraging tree regrowth by cutting them back to ground level. Harvesting branches rather then whole trees = prevent deforestation, soil erosion and desertification. Controlled burning of grassland to avoid wildfires. Crop rotation to keep a varied supply of nutrients in the soil and prevent soil erosion and desertification. Stone lines along the soil = contours keep it in place, prevent erosion and improve crop yields. Projects such as this can involve the whole community and give them a sense of ownership and responsibility. Managing grazing land = avoids overgrazing, soil erosion and desertification. Management of the effects of desertification = Short term aid of food, water and medicine is given when the situation is at its worst.