Climate and Vegetation Regions of the World: Tropical Rainforests

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1 TROPICAL RAINFORESTS The Main Biomes (Vegetation Regions) A biome is a large geographical area with distinctive plant and animal groups, which are adapted for that particular environment. The climate and geography of the area determines the biome. Each biome consists of many ecosystems that have adapted to the climate and the environment. Any change in the ecosystem, can impact other biomes in other parts of the world. Vegetation across the world is divided into the following biomes: The Forest Biome Tropical Rainforests Deciduous Forests (trees that shed their leaves annually) Coniferous Forests (evergreen cone-bearing trees or shrubs) Savannah Biome Grasslands Biome Desert Biome Tundra Biome Tropical Rainforest Deciduous Forest Coniferous Forest Version 1: December 2013 Copyright My Cyberwall

2 Savannah Grasslands Desert Tundra Version 1: December 2013 Copyright My Cyberwall

3 The pie graph below shows the breakdown of land area of the different biomes: The Forest Biome Through the ages people have been dependent on forests for shelter, food, wood for their houses, weapons and energy. Wooden Roof Beams Latex (Rubber) from Trees Trees Provide Us With Food Trees Provide Us With Fuel Version 1: December 2013 Copyright My Cyberwall

4 The forest biome is dominated by various tree species. In some forests, the dense canopy of the treetops grows so closely that sunlight cannot penetrate to the ground. In other areas the trees are further apart and sunlight can partially penetrate the tree canopy. Tropical Rainforests Rainforests cover 6% of the earth s surface and are very important because they produce oxygen as well as provide us with many products that are grown there, such as medicines, rubber, coffee, fruit, nuts, oils and timber. Coffee Plantation Location of Tropical Rainforests Tropical rainforests are found close to the equator (in the tropics) where it is hot all year round with a very high rainfall. The largest tropical rainforests are located in the Amazon basin (South America), the Congo basin, on the coast of Guinea (West Africa) as well as in South East Asia. Smaller tropical rainforests are found in Central America, India, Madagascar, Australia and the surrounding Pacific islands. Version 1: December 2013 Copyright My Cyberwall

5 The Amazon Rainforest (also known as the Amazon jungle) is the world s largest tropical rainforest and covers a land area of 7 million sq km. It is found mainly in Brazil, but with significant areas in Peru and Colombia as well as smaller areas in Ecuador, Bolivia, Guyana, Suriname and French Guiana. The Amazon Rainforest accounts for more than 50% of the world s remaining rainforest. It has the greatest variety of plants and animals on Earth. One fifth of the world s plants and birds and one tenth of the world s mammals, as well as over 2,5 million species of insects are found here. Amazon Rainforest Version 1: December 2013 Copyright My Cyberwall

6 The Congo Basin Rainforest is the second largest rainforest in the world and is located in West Africa. It is famous for its gorillas, chimps and elephants. The Guinea Rainforest is on the west coast of Africa and borders the Atlantic Ocean. It is situated between Guinea Bissau and Sierra Leone. Over 100 endemic species (found nowhere else in the world) are found here, but 40% are endangered as a result of poaching and habitat destruction, caused by mining projects and agriculture. Congo Basin Rainforest Gorilla in Guinea Rainforest Also in Africa is the Madagascan Rainforest. Around 90% of it has already been destroyed. Around 75% of the species found here are endemic, such as species of lemurs and a primate called the aye aye. There are over 1000 species of orchids found here, of which 85% are endemic. Madagascan Rainforest The Central American Rainforest once covered the whole area. Large areas have now been cleared for cattle ranching and sugar cane plantations. Many endemic animals and plants are found here, including a variety of tropical birds. Central American Rainforest Mangrove River, Mexico - Version 1: December 2013 Copyright My Cyberwall

7 The South East Asian Rainforests cover an area from India and Burma in the west to Malaysia in the east. They are the oldest rainforests in the world, thought to be 70 million years old. Bangladesh has the largest area of mangrove forest in the world. Many critically endangered plants and animals are found here, such as the two- horned Sumatran rhino and the Malaysian tapir, of which there are thought to be only around 50 left in the wild. South East Asia Rainforest Langkawi Island, Malaysia The Australasian Rainforest is found in a small band on the North Queensland coast in Australia. Rainforest once covered the entire continent. An amazing diversity of plants and animals is found in this area. Australasian Rainforest North Queensland, Australia The Pacific Island Rainforests are found in the Pacific Islands, in places such as Hawaii, Fiji, Tahiti and the Solomon Islands. Pacific Island Rainforest Kauai, Hawaii Version 1: December 2013 Copyright My Cyberwall

8 Rainforest Climate Rainforests occur near the equator and for this reason the weather is always hot. They have a tropical wet climate. The temperature in a rainforest does not vary a lot from month to month. It is usually around 34 C and does not fall much below 20 C. Humidity is very high. Because of the high temperatures, there is a lot of water evaporation, which results in frequent rainfall. 50% of the rainfall in the rainforest is due to this evaporation. It rains for more than 90 days a year in the rainforest and the average annual rainfall is around 200 cm and can exceed 1000 cm. A lot of this rain does not reach the ground, but stays on the trees. Mist After a Heavy Rainfall There are only two seasons in a rainforest, dry and wet. The dry season is very short. The graphs below show the average temperatures and rainfall in Manaus, Brazil in the Amazon Rainforest (03 06'S 01 00'W). Maximum temperatures are between 30 C and 34 C throughout the year. The minimum temperature does not vary a lot and is around 22 C. Source: Hong Kong Observatory Version 1: December 2013 Copyright My Cyberwall

9 The rainfall graph for Manaus below shows that the highest rainfall occurs between January and June, with June to October being drier months. Source: Hong Kong Observatory Rainforest Vegetation Over 70% of the vegetation in the rainforest is trees. There are more types of trees in the rainforest than in any other area of the world. Most of the trees in tropical rainforests are broadleaf, evergreen trees. Tropical Rainforest Plants Version 1: December 2013 Copyright My Cyberwall

10 Palms and tree ferns are also found in the rainforest. Palms and Tree Fern Plants The vegetation is so dense that not much light reaches the forest floor. The types of plants found in rainforests vary depending on the location of the rainforest. These plants are well adapted to the hot, wet climate, for example, with grooved leaves, which do not break from the weight of the rain. Trees of the same species do not usually grow together in the rainforest. This protects them from disease and insect infestation. The rainforest is often referred to as the world s largest pharmacy as there are many plants that are found there which are used as medicines, for example, quinine which is used to treat malaria and rosy periwinkle, which is used to treat leukemia. There are four distinct layers of vegetation in the rainforest, as shown in the diagram and described below. Version 1: December 2013 Copyright My Cyberwall

11 Forest Floor This is the bottom layer of the rainforest, at ground level and is mostly in the shade. A lot of vegetation falls to the forest floor and is broken down by decomposers such as termites and earthworms, as well as heat and humidity. There is not a lot of vegetation that can grow between the trees. Mainly ferns, moss and dead leaves are found in this layer. The plants here are well adapted, for example with large leaves to absorb as much sunlight as possible. During heavy rains, the forest floor can flood. Understory/ Lower Canopy Heavy Rains Cause Forest Floods This is the layer above the forest floor and where the trunks of trees of the upper canopy, as well as smaller trees, plants and shrubs are found. There is high humidity and shade in this layer. Climbers called lianas are often found in this layer and climb up trees to get to the sunlight. Upper Canopy Lianas Climbers This is the next layer and is full of life. The canopy is typically about 20 to 40 m high. There is more sunlight than the lower levels. Many air plants, called epiphytes, such as the orchid, grow here. Their roots do not touch the ground, so they live off other plants, getting their nutrients and moisture from the air. Epiphytic Aroid Grows on Tree Trunk Version 1: December 2013 Copyright My Cyberwall

12 Emergent Layer This is the top layer and is above the upper canopy. Tall trees that need a lot of sunlight grow here up to 40 m, above the forest, although some can reach as high as 70 m. These trees often have shallow roots with buttresses for extra support in the poor, wet soil. The leaves of these trees are usually small and dark green to reduce water loss. Rainforest Wildlife Tall Rainforest Trees There is a huge variety of animals that live in the rainforest, especially insects. In fact, some species have not even been identified yet! Half of the world s species of animals and insects live here. The tropical rainforests support one and a half million species of plants and animals. Rainforest animals are well adapted to life in the trees, for example, by having a diet that consists mainly of fruit. Examples of wildlife found in the rainforest canopy include birds, insects, bats, squirrels and monkeys. A Toucan Tarsier Monkey Version 1: December 2013 Copyright My Cyberwall

13 In the understory of the rainforest, snakes, ocelots, tree frogs and birds such as guans are found. Boa Snake Tree Frog Ocelot Black Throated Piping Guan Tapirs and other herbivores are found on the forest floor, and are hunted by jaguars and snakes. Tapir Jaguar Version 1: December 2013 Copyright My Cyberwall

14 Insects are the largest group of animals found in the rainforest. These include butterflies, mosquitoes, stick insects and ants. Butterfly Wikimedia Creative Commons Attribution Share-Alike: Muhammad Mahdi Karim Stick Insect Wikimedia Creative Commons Attribution Share-Alike: Fritz Geller-Grimm &FelixGrimm Mosquito Wikimedia Creative Commons Attribution Share-Alike: Alvesgaspar Deforestation Deforestation is the permanent removal of a forest or woodland, for conversion to another use, such as farmland or for urban development. Logging of trees and clearing of the rainforest to make way for plantations, have endangered the rain forest s plant and animal life, as well as caused irreparable damage to the Earth s environment. Nearly 80,000 acres of rainforest are destroyed in this way, every day, causing 50,000 species to become extinct every year. Version 1: December 2013 Copyright My Cyberwall

15 Most deforestation these days occurs in tropical areas. Up to 90% of the rainforests in West Africa have been lost due to deforestation. Deforestation takes place for many reasons. Trees are cut down for timber (logging), to supply wood for firewood, building materials and wood products such as furniture and paper. Deforestation Clearing Land for Agriculture Other products that come from trees include: resins, waxes, fruits, nuts, berries and maple syrup. A growing population has increased demand for these products. The main reason for cutting down forests is for agricultural use. Subsistence farming accounts for 48% of deforestation, commercial farming for 32%, whilst logging is 14% and fuel wood removals, 5%. Deforestation means permanent loss of potential life-saving medicines and has been found to be a major cause of global warming. Trees and other plants remove carbon dioxide from the atmosphere. When these trees are cut down, this carbon dioxide is released back into the atmosphere (instead of being turned into oxygen by trees) and this accounts for approximately 20% of the world s greenhouse gas emissions. Deforestation Causes Loss of Life-Saving Medicines Version 1: December 2013 Copyright My Cyberwall

16 Trees and other plants remove carbon dioxide from the atmosphere. When these trees are cut down, this carbon dioxide is released back into the atmosphere. Go to the module on Deforestationin Save Your Planet, for more information: People in the Rainforest Although tropical rainforests have been home to indigenous people for centuries, relatively few people live in rainforests because of the dense vegetation, which makes it difficult to move about. The Mayans, Incas and Aztecs are well known indigenous people who lived in the rainforests. Indigenous groups live with nature and understand the importance of their environment. They use plants for food as well as natural medicines. The Yanomami people in South America live in the Amazon Rainforest. There are around 20,000 Yanomami people who live in groups of 50 to 400 people in around 200 villages. They grow bananas, sugarcane, mangoes, sweet potatoes and papaya, as well as gather food and hunt. People of the Amazon Rainforest -The Yanomami People Wikimedia Creative Commons Attribution Share-Alike: Ambar Version 1: December 2013 Copyright My Cyberwall

17 Many tribes still live in the African rainforests. These include Pygmies who rarely grow taller than 1,5 m. They are hunter-gatherers. A Pygmy Tribe of Uganda Attribution: Hector Cornesa/Shutterstock.com African Pygmies Wikimedia Creative Commons Attribution Share- Alike: Keystone View Company Other tribes living in the rainforests of Africa include the Aka in Central Africa and in northern Congo, the Baka in south Cameroon and the Twa in central Zaire. These make up a total of forest dwellers in a large forest area, giving a very low population density. DRC Aka Pygmy Family Wikimedia Public Domain Cameroon Baka Tribe Wikimedia Public Domain These days, people who live in the rainforest have displaced indigenous people, in order to conduct activities such as mining and agriculture. Many indigenous people have also chosen to join modern society. Version 1: December 2013 Copyright My Cyberwall

18 Temperate Rainforests There is another type of rainforest, known as Temperate Rainforests that are found along the Pacific Coast of USA and Canada, from California to Alaska, as well as in Tasmania, Chile, the United Kingdom and Norway. Tongass Rainforest - Alaska Wild Rivers National Park Tasmania, Australia Version 1: December 2013 Copyright My Cyberwall