From IB syllabus:

Explain the concept and importance of biodiversity in tropical rainforests. Examine the causes and consequences of reduced biodiversity in this biome.

Definition of Biodiversity:
Biodiversity has been most generally defined as the "full variety of life on Earth". More specifically, biodiversity is the study of the processes that create and maintain variation. It is concerned with the variety of individuals within populations, the diversity of species within communities, and the range of ecological roles within ecosystems.

Importance of biodiversity
Environmental problems : Earth functions like a complex system with very complex components that affect each other. Each species -- from the lowliest microbe to humans -- plays a part in keeping the planet running smoothly. In this sense, each part is related. If a lot of those parts suddenly vanish, then the machine that is Earth can't function properly.

For example, the crops that we grow though our clever use of agriculture are enabled by the nitrogen present in the soil. This nitrogen nourishes and strengthens our crops. But where does it come from? Worms, bacteria and other life found within the soil love to decompose vegetation. When they eat, these organisms produce nitrogen as waste. This nitrogen is used to make soil rich.

If we have a small bottle with a group of dominating predators and prey together, soon they will both die out because there is no sustainability. Likewise, if humans manipulate the environment and decrease biodiversity, our environmental sustainability significantly decreases.

Economic Importance of Biodiversity:

• Biologically diverse ecosystems are typically more productive than non-diverse ones because they contain a wider array of resources, and it is impossible for us to use up all of them at once.
• Biodiversity provides many different resources that can be exploited economically, such as fibres wood, fuels, rubber, and silk.
• Many medicines are made from extracts taken from the Amazon rainforest
• Biodiverse environments can often be used as tourist attractions
• The Amazon rainforest is one of the most dominant rubber-producers in the world
• Illegal biological trade exploiting wildlife
• Wood industry
• payments for ecological services rendered by the Amazon such as the carbon retaining in its forests could go a long way to preserving them, a new study has found.


Concept of biodiversity
This is the variety of all forms of life on earth e.g. plants, animals and micro-organisms. This includes variations, interdependence and habitat diversity.
Biodiversity is so important in the rainforest because many of the different species depend on one another. It is important for the world because it allows for greater genetic variation, this stabilises ecosystems and makes them resilient to damage. Furthermore it expresses evolutionary potential that will be lost if species go extinct and their genes are removed from the gene pool.

The Amazon rain forest
  • covers 40% of South America
  • has 40,000 plant species, 1000 diff. trees
  • 427 diff. mammals,
  • receives 160 to 400 inches of rain per year.
  • 20% of the world’s oxygen is produced by the Amazon rainforest

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Map to show the distribution of tropical rain forests external image Pfjg56SixHw0d9QJ6xNv6SffexFGd4r6gr2zdT3dR7EjqqkkrxvxPUawZUHxkdy7UQPXtHo_Fip50nPEl5xFBKXqzDXQuzIJJmkGMjPWfMVE0Bgo_A
  • Rainforests cover only 6% of earth’s surface, yet they are home to over half of world’s species.
  • The Amazon is home to the greatest variety of plants and animals on Earth. 1/5 of all the world's plants and birds and about 1/10 of all mammal species are found there.
  • One-fifth of the world's fresh water is in the Amazon Basin

Things being done to protect the Amazon forest
  • Serra dos Órgãos only covers 1% of the national territory of Brazil
    • This rich biodiversity is largely due to the high variation in altitude within the range, creating many different habitats and unique environmental conditions
    • This mountain range is home to a rich variety of wildlife and a great number of species, including over 458 bird species, and approximately 620 species of orchids

  • Reserva Ecológica de Guapi Assu (REGUA) is working to protect as much of this forest as possible
  • Guapi Assu Reserve funding to REGUA to buy land and increase the size of the protected area in the central corridor of the Serra dos Órgãos Mountains

The UN declared 2010 to be the Year of Biodiversity. Their website is __here__. Their goals for this year are:
  • To enhance public awareness of both the importance of and the treat to biodiversity.
  • To raise awareness of community and government projects that have already taken steps to preserve biodiversity.
  • To promote innovative solutions to reduce the treats posed to biodiversity.
  • To enourage individuals as well as governments and organisations to take immediate steps to stop the loss of biodiversity.
  • To start a dialog between stakeholders for measures to be taken beyond the year 2010.

For updates on ‘biodiversity events’ you can like __this facebook page__ related to the cause.


Causes of reduced biodiversity in tropical rain forest

· Philosophical/ethical attitudes that do not find significance in preserving tropical rain forests
· Land speculation and the speculation of land titles
o 80% of tropical forests controlled by governments

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· Dams – for hydroelectric power
o Itaipu Dam & Tucurui Dam in Brazil
· Climate change --> drought
· Selective logging – only logging one particular species of tree
· “Slash-and burn”, shifting cultivation with higher population pressure
o reduces soil fertility
· Agricultural colonization – by large modern industries/MNCs
· Forests cut down to be used for the pasture of cattle
o In eastern & south eastern Para & northern Mato Grosso (Brazil)
· Mining
o Gold mining produces toxic waste – more than 100 tons of mercury have been emitted into the Amazon by miners
o Greater Carajas Project in south-eastern Amazonia
· Forestry of a single species of tree
· Lightening --> forest fires
· Deforestation for fuel/paper/coalexternal image -yXHZn5kBEQgnpifT-06uYjPuQ-5hdi8VBN93W3QG1_zSCHmae40qV_QRuA5TXXWxVKI_GfIle206sK3qXWkVWJk1sY13K9uNogdBu9kCrjG4tpajQ
· Government policies --> Government encouraging the production of a certain crop/the growing of certain trees
· Civil war/disruptive social change
· Exploitation of resources by rebel groups
o Rebel groups in the D R Congo mining --> for economic benefit

· Ecotourism
o Overuse of roads and waterways, disturbance of animals and migration patterns
· Governments support logging
o Benefits the national economy
· Establishment of transportation networks
o 8-18 million hectares of the Brazilian Amazon in danger of deforestation for the building of roads
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· Growth in human population --> increased strain on nations resources => deforestation of Amazon
· Urbanization
o Encroachment of cities on rain forests

Consequences of reduced biodiversity in tropical rainforest

Rainforests once covered 14% of the earths land surface now they cover 6%

Governments may receive pressure from groups or people to address the issue of biodiversity reduction, and “save nature”
Resentment toward groups that profit from their damage.

A larger wildlife diversity helps to limit the spread of animal bacteria to humans
- negative implications for people’s diets
- habitat loss - reduce number of species
reduced plant diversity prevents important aspects of ecosystem functioning
- less plants growing leads to less plants to take up carbon dioxide which may increase the effects of climate change
- ecosystems are intrumental as a buffering sytem for extreme climatic events like drought, flood and fire
cause disputes between the exploiters and exploited
Greater wildlife diversity may decrease the spread of many wildlife pathogens to humans
Extinction of indigenous way of life
-Many cultures have spiritual, recreational, and religious values to ecosystems.
- Reducing the bonding value of shared experiences
Changes in their way of life
- A change in the interaction between indigenous people & tourists
- companies gain short term profit
- Resources will eventually run out because they are extracting more than nature’s ability to replenish itself
- Specialists say that the remaining area of rainforests can be consumed in less than 40 years
Extracting resources in order to make profit (wood)
- Agricultural benefits from such as slash and burn
- One & a half acres of rainforest is lost every second with vast losses for both developing & industrial countries
-Reduction in ecotourism, pharmaceuticals, cosmetics, and fisheries loss of profit, lose money to companies.

Recommended reading: The Last Flight of the Scarlet Macaw by Bruce Barcott
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