The Living world. Tropical rainforests (core content) Revisio n undert aken. Cover ed in class?

Transcription

1 The Living world Using an example from the UK, I can explain the interrelationship within the natural system. I can define and give UK examples of producers consumers, decomposer, food chain, food web and nutrient cycle I can explain their interdependence of each of the above and explain how changes might affect each other. I can describe the distribution and characteristics of global ecosystems around the world. Tropical rainforests (core content) I can describe the physical characteristics of the tropical rainforests I can explain the interdependence of the climate, water, soils, plants, animals and people in a tropical rainforest I can explain how plants and animals have adapted to the physical conditions of tropical rainforests. I can describe and explain the problems and issues with changing biodiversity within the tropical rainforest. I can describe and explain the changing rates of deforestation. I can use a case study to explain the causes of deforestation subsistence and commercial farming, 1. Logging, 2. Road Building 3. Mineral Extraction 4. Energy Development, 5. Settlement 6. Population Growth I can use a case study to explain the impacts of deforestation 1. Economic development 2. Soil erosion, 3. Contribution to climate change. I can explain the importance and value of the tropical rainforest on a local, national and international scale. I can explain why it is important the tropical rainforest should be managed sustainably. I can explain how the tropical rainforest can be managed sustainably using a range of methods 1. Selective logging and replanting 2. Conservation and education 3. Ecotourism 4. International agreements about the use of tropical hardwoods, 5. Debt reduction. Cover ed in class? Revisio n undert aken

2 What is an ecosystem? An ecosystem is a living community of plants (flora) and animals (fauna), which is linked to the natural environment where they live. Each element in the system depends upon and influences others. They are interrelated. There are often complex relationships between the living (biotic) and non-living (abiotic) components. Abiotic components include the climate (primarily temperature and rainfall), soil, water and light. Ecosystems can be identified at different scales. A local ecosystem can be a pond or a hedge. Larger ecosystems can be lakes or woodlands. It is also possible to identify ecosystems on a global scale, such as tropical rainforests or deciduous woodland. These global ecosystems are called biomes. How do ecosystems work? Every ecosystem works in the same way: 1) Plants use sunlight, water and nutrients from the soil to produce their own food via photosynthesis and are called producers. 2) Animals feed on plants (herbivores) or animals (carnivores) and are called consumers. 3) Fungi and bacteria feed on dead and waste material and make things break down or rot. These are called decomposers and recycle nutrients for plants to use again. Without plants, all other living things would die. A food chain shows the different elements that live in an ecosystem, and what eats what to survive. A food web is more complex and shows all the different elements in a habitat and how they interrelate.

3 The Nutrient Cycle Changes to the ecosystem Different parts of an ecosystem depend on each other, and there's a fine balance between them. A change in one part of the ecosystem will affect other parts and upset the balance. Ecosystems around the world are facing changes including: Climate change - which can affect where species can live, when they reproduce and the size of their populations Habitat change - the conversion of land for farming can lead to a loss of habitat for huge numbers of species Pollution - which, for example, can reduce oxygen levels in wetlands and rivers (killing fish), and also cause rapid plant and algae growth (called algae blooms)

4 Distribution of Biomes Different ecosystems are found in different parts of the world due to the influence of climate and soils. The vegetation adapts to the climate and soils and is in harmony with it. Global ecosystems are known as biomes. The dominant type of vegetation cover usually defines a biome. On a global scale, climate is the main factor which influences the distribution and characteristics of natural vegetation cover. This is because climate affects the growth conditions for vegetation: 1) Temperature - especially the seasonal pattern and length of the growing season. 2) Precipitation - particularly the total amount and how it's distributed throughout the year. 3) Sunshine - which determines the amount of light available for photosynthesis. 4) Rates of evaporation, transpiration and humidity. Tropical rainforest Climate The daily temperature is about 28C. It never goes below 20C and rarely above 35C. It is a very wet climate, at least 2000mm of rain falls a year. This makes the atmosphere very hot and humid. There are no real seasons. Each day's weather is the same - starting off hot and dry, with thunderstorms and heavy rain in early evening.

5 Soil The soils are red in colour and rich in iron. They have a thick layer of litter (dead leaves etc) but only a thin fertile layer because the leaves decompose very quickly in the humid conditions. The soils are not very good for plants to grow in as nutrients are quickly washed out of the soil because of heavy rainfall. Vegetation The vegetation in rainforests grows in distinct layers and has adapted to the climate and poor soils. Trees are very tall and trunks are thin to reach sunlight. Buttress roots support these tall trees in shallow soils. Lianas are woody vines that climb high to reach the sunlight. Leaves in the tropical rainforest have drip tips to allow rainfall to drip down to the lower layers and shed heavy rainfall easily. Case Study: Tropical Rainforest

6 - Tropical rainforest is removed for a range of reasons. This has economic, social, political and environmental repercussions. - Tropical rainforests are increasingly at threat from deforestation. Governments are viewing the rainforests as an untapped resource which can aid them in economic development. - Malaysia is a country in south-east Asia. Along with neighbouring countries, the natural vegetation is tropical rainforest. Nearly 63% of Malaysia is forested and commercial tree crops, primarily rubber and oil palm, occupy a further 13%. Trees and forest cover an area equivalent to the whole of the UK. Malaysian rainforests support over 5500 species of flowering plants, 2600 species of tree and 1000 species of butterflies. The rate of deforestation in Malaysia is increasing faster than in any other tropical country in the world, some 140,200 ha of forest have been lost on average each year. Malaysia Case Study Deforestation is the cutting down of trees, often on a very large scale. Logging: Malaysia became the world s largest exporter of tropical wood in the 1980s. Clear felling, where all trees are chopped down in an area, was common. This led to the total destruction of forest habitats. Recently, clear felling has largely been replaced by selective logging, where only fully-grown trees are cut down. Trees that have important ecological value are left unharmed. Road Building: Roads are constructed to provide access to mining areas, new settlements and energy projects. Logging requires road construction to bring machinery and take away timber. Energy Development: in 2011, after five decades of delays, the controversial Bakun Dam in Sarawek started to generate electricity. The Bakun Dam (205m) is Asia s highest dam outside of China. Several more dams are planned to boost Malaysia s electricity supplies. The dam supplies energy for industrialised Peninsular Malaysia. The dam sreservior flooded over 700km2 of forests and farmland. Mineral Extraction: (Mainly tin and smelting) is common in Peninsular Malaysia. Rainforest has been cleared for mining and road construction. Drilling for oil and gas has recently started in Borneo.

7 Population Pressure: In the past, poor urban people were encouraged by the government to move into the countryside from the rapidly growing cities. This is called transmigration. Between 1956 and the 1980s, about 15,000 hectares of rainforest was felled for the settlers. Many then set up plantations. Commercial Farming: Malaysia is the largest exporter of palm oil in the world. During the 1970s, large areas of land were converted to palm oil plantations. Plantation owners receive 10 year tax incentives, so increasing amounts of land have been converted to plantations. Subsistence farming: Tribal people living in the rainforest practise subsistence farming. Traditionally, local communities would hunt and gather food from the forest and grow some food crops in cleared pockets of forest. This type of farming is small scale and sustainable. One method of clearing land is slash and burn. This burning creates valuable nutrients that helps the plants grow. These can grow out of control, destroying large areas of forest. Malaysia Effects/Impacts of Deforestation Social Economic Environmental Positive 1) Poor urban dwellers have had the opportunity to set up businesses and improve their quality of life. 2) Better transportation links 3) Large scale farming provides food 4) 1) Area has become economically profitable and has contributed to Malaysia's GNP. 2) Profits can be used to improve Malaysia's infrastructure and level of development. Negative Indigenous tribes forced to move. Profits from the businesses in the area rarely go to local people 1) Thousands of hectares of rainforest have been destroyed. 2) Amount of virgin rainforest cover has decreased dramatically 3) Loss of habitats 4) Survival of species, including the orang-utan, is threatened

8 Malaysia: Managing Tropical Rainforests Tropical rainforests need to be managed sustainably. International co-operation is needed. In order to manage the rainforest sustainably a variety of management techniques have been used in Malaysia. National Forest Policy Widespread logging in Malaysia started after the Second World War due to improvements in technology (e.g. chainsaws, trucks etc). The government responded by passing the National Forestry Act in The Act paved the way for sustainable management of Malaysia's rainforests and had the following aims: develop timber processing to increase the profitability of the exported wood and reduce demand for raw timber. The export of low-value raw logs is now banned in most of Malaysia. encourage alternative timber sources (e.g. from rubber trees) increase public awareness of the forests increase research into forestry involve local communities in forest projects One of the main initiatives of the 1977 Act was to introduce a new approach to forest management known as Selective Management System. This is recognised as one of the most sustainable approaches to tropical forestry management in the world. Selective Logging and Replanting provides careful consideration. But, a lack of trained officials to enforce and monitor the system across the country has led to the continuation of abuses and illegal activities. Remedial measures, such as replanting, have not always been carried out satisfactorily. Deforestation is still taking place in Borneo where land is being converted into oil palm plantations. Permanent Forest Estates and National Parks The government to identify Permanent Forest Estates. These are areas which are protected with no development or conversion of land use allowed. Large areas of forest however, are used for commercial logging. Some 10% of the forested land (mainly primary forest areas) have special conservation status ensuring the survival of the rainforest habitats and species. Forest Stewardship Council The Forest Stewardship Council (FSC) is an international organisation that promotes sustainable forestry. Products that have been sourved from sustainably manged forests carry the FSC label. The FSC aims to educate manufacturers and consumers about the need to buy wood from sustainable sources. It also aims to reduce demand for rare and valuable tropical hardwoods. Developing Tourism Malaysia has promoted its forests as destinations for ecotourism. This aims to introduce people to the natural world without cauisng any environmental damage. The great benefit of ecotourism is that it enables the undisturbed natural environment to create a source of income for local people without it being damaged or destroyed.

9 Worldwide Initiatives Rainforests are valuable resources which poor countries want to use to expand their economies and increase their level of development. As well as timber rainforests occupy land that could be used for commercial agriculture such as plantations or ranching. Valuable mineral resources such as bauxite, copper or iron may be present in the rock below the forests. To expect countries not use these resources available to them is naive, even though they are important at a global scale. To encourage poorer countries to not develop their rainforest areas various strategies have been used globally. Debt relief: rainforests are recognised globally and attributed a monetary value. Countries are paid to maintain the rainforests, this could take the form of debt relief (countries are relieved of some of their debt in return for protecting their rainforests) Carbon sinks: in recocognition of rainforest's role in reducing global warming money is given to support rainforest areas as a way of reducing carbon dioxide levels globally e.g. Gola Forest, Sierra Leone is supported by the European Commission, the French Government and the RSPB. The Living World Answer the following questions to demonstrate your knowledge and help with your revision Ecosystems exist at a range of scales and involve the interaction between biotic and abiotic components An example of a small scall ecosystem: Hene Centre Pond Complete the key terms list below by adding the correct definitions: Ecosystem: Biotic components: Abiotic components: Describe the pond ecosystem shown opposite

10 Complete the table below with the correct definitions and give an example for each that would be found in a freshwater pond: Term Definition Example Producers Consumers Decomposers Food chain Food web Nutrient cycling Ecosystems are very fragile and if there is a change to one component it may well have a knock-on effect on the rest of the ecosystem. Complete the natural and human causes of change in an ecosystem: Natural changes Changes due to human activity How can changes affect the pond ecosystem? Complete another flow diagram below for another change: More perch (predators) are added to the pond Smaller fish and frogs are eaten Less food for creatures higher up the food chain, e.g. herons More creatures lower down the food chain like slugs

11 Large-scale ecosystems are known as global ecosystems or biomes (see map below): Explain why ecosystems tend to form broad belts across the world from east to west, parallel to the lines of latitude. Complete the table below outlining the location and characteristics of each biome: Global ecosystem Tropical rainforest Location Characteristics Desert Tundra Tropical Rainforests Tropical rainforest ecosystems have a range of distinctive characteristics Where are tropical rainforests found? What is the climate like?

12 Why is the temperature constantly high in the rainforest? Why is the rainfall high? Why does the amount of rainfall vary throughout the year? Give 2 reasons why the soils in tropical rainforests are infertile: Annotate the photograph below to describe and explain how plants have adapted to the rainforest:

13 Explain 3 animal adaptations that enable species to survive in tropical rainforests: Deforestation has economic and environmental impacts Every 2 seconds an area of rainforest the size of a football field is destroyed! Rainforests once covered 15.5 million km2, but now it is just over 6.2 million km2. Why is the rate of deforestation now decreasing in Brazil? What is happening to the rainforests in Malaysia compared to Brazil? A case study of a tropical rainforest: Malaysia Describe the location of the Malaysia and its rainforests

14 What are the causes of deforestation in the rainforests in Malaysia? Complete the table below to outline each of the causes: Cause Information Subsistence and commercial farming Logging

15 What are the impacts of deforestation? How does deforestation lead to soil erosion? _ How does deforestation contribute to climate change? Complete the table below to show how deforestation can have both economic gains and economic losses: Economic gains for the country Economic losses for the country

16 Tropical rainforests need to be managed to be sustainable Complete a mind map below to explain why tropical rainforests are valuable to people and the environment:

17 Rainforests need to be managed sustainably so that we can still use valuable resources but without causing long-term damage for future generations. Complete the table below outlining how rainforests can be managed sustainably include specific facts where possible: Sustainable strategies How do they work? Selective logging and replanting Conservation and education Ecotourism International agreements Please see your teacher if there is any are of this that you are unsure of. If you could like your work to be marked please present this to a teacher and we will go through it with you.

18 Exam Questions 1. Explain and describe the features of a small-scale ecosystem. (4 marks) 2. Using a named example, explain how change can have positive and negative effects on an ecosystem. (6 marks) 3. Describe the distribution on the location of the world s biomes. (6 marks) 4. Describe and explain the features of the vegetation shown in Figure 7. [6 marks] Figure 7

19 5. Describe and explain the causes to deforestation, using a case study. (8 marks) 6. Photo A shows a hydroelectric dam in Sarawak, Malaysia. Evaluate two possible environmental impacts of developments like the Bakun Dam. (4 marks) Photo A 7. Explain, with reference to an example, why it is important to retain biodiversity. (9+3 Spag marks)

20 8. The rainforest is more valuable when left intact than when destroyed. Using a case study, use examples to support or challenge this view. (9 marks + 3SpaG) 9. Describe and explain two benefits of international cooperation in sustainably managing tropical rainforests. (4 marks). Describe and explain three ways rainforests can be managed more sustainably, providing examples to consolidate your answer. ( 9 marks + 3 Spag)