Ecosystem in Danger: The Amazon Rainforest Dinorah Velasco Per. 5
The Amazon Rainforest is the world's largest tropical forest (twice the size of India). It covers much of northwestern Brazil and extends into Columbia, Peru, and other South American countries. The plants here store 17% of the world’s carbon, which helps regulate the earth’s temperature. It has an immense biodiversity, which is why we need to protect it.
The Amazon Rainforest was most likely formed during the Eocene Era, which was a time when greenhouse gases (more specifically carbon dioxide and methane) played a significant role in controlling the surface temperature. The Atlantic Ocean widened and provided a more warm and moist climate to the Amazon basin. They say that the extinction of dinosaurs and wetter climates might have allowed the rainforest to spread out.
There have been significant changes in the rainforest vegetation over the last 21,000 years. Some evidence indicates that rainfall in the basin during the Last Glacial Maxium (last period of Earth's climate when ice sheets were at their greatest extension) was lower than it is now.
Human inhabitants first settled in the Amazon region 11,200 years ago.
Now, more than 30 million people live in the Amazon; there's hundreds of indigenous and ethic groups that live there. They depend on the Amazon region for clothing, medicines, agriculture, food, shelter, and livelihoods.
The Amazon Rainforest is home to more than one million plant and animal species. The Amazon River contains the largest number of freshwater fish species in the world. In this warm and prey-plentiful rainforest, many wildlife can live comfortably.
There's about 427 types of mammals, 40,000 plant species, 2.5 million insect species, 1500 bird species, 400 amphibian species, 2,500 fish species, and 378 reptile species.
Examples of Animals That Live in the Amazon: Jaguars, sloths, mawcaws, anteaters, toucans, giant otters, pink river dolphins, harpy eagles, boas, dart poison frogs, piranhas, anacondas, spider monkeys, electric eels, bromeliads, passion fruit plants, etc.
An orangutan is an example of a specialist species because they need a specific space to live in and cannot be moved from place to place. Large predators, like jaguars, are considered a generalist species.
- Interspecific competition: Squirrels & chipmunks; they compete without each other for acorns and other resources but they don't compete with each other for nesting sites or mates.
- Predation: Ocelot eats monkeys.
- Parasitism: Parasitism: Cicadas (an insect) and trees; cicadas lay their eggs on the tree; when they hatch, the nymph drops down to the ground and burrows to the roots of the tree and sucks the sap out of them.
- Mutualism: Hummingbirds and flowering plants; The hummingbird benefits from the nectar (a source of energy for the plants). The plants rely on the hummingbirds to pollinate them.
- Commensalism: Animals eating plant seeds; when seeds travel on animals’ fur or feathers. The seed will eventually fall off and plant itself, growing a new tree. The plants are benefiting from this and the animals are unharmed.
- Resource partitioning: Resource partitioning may occur between frogs and reptiles because they both mainly feed on insects. A gecko is not nocturnal so it hunts for food during the day; the red-eyed tree frog is nocturnal and does its hunting at night.
R-selected species: Piranha. They lay around 5,000 eggs
K-selected: Pygmy Marmoset. Females usually give birth to 3-4 offspring, plus twins. Its slow for them to produce offspring because their natural habitat gets destroyed, so they don't have enough food or shelter.
Population: The Amazon population is mainly urban; many indigenous groups live in villages deep in the forest. It's estimated that 170 groups live in the Amazon; 25% of the Brazilian population live in the rainforest. Nearly all of the Amazon rainforest has been touched by man, with the exception of some groups still living in the rainforest that are classified as "uncontacted tribes." Those living in the Amazon get their food, medicines, clothing, etc. come primarily from this forest. Indigenous groups have to fight for their land, mostly through peaceful demonstrations. Many people outside the Amazon want to help them in protecting their culture.
- Primary Succession: Flooding happens often from the abundant amount of rain. This strips the topsoil, so the environment must create new soil.
- Secondary Succession: Large areas of trees are cut down to grow crops; after a few years, the soil becomes infertile. Secondary succession sets in, fertilizing the soil and growing small plants and trees again until the forest has grown back.
The Amazon Rainforest is mostly warm and humid year round. The average annual temperature is above 20 degrees Celsius. Rainfall varies from 250 centimeters of rain per year to about 450 centimeters per year; so rain ranges from about 8 to 14 feet per year.
Freshwater Systems: The Amazon River is the most voluminous river on Earth; it's 11 times the volume of the Mississippi. The river's mouth may reach up to 300 miles wide; 500 billion cubic feet of water flow into the Atlantic. The Amazon's daily freshwater discharge into the Atlantic is enough to supply New York City's freshwater needs for 9 years.
It is calculated that 106 million cubic feet of sediment are swept into the ocean everyday. The silt deposited at the mouth of the Amazon is Majaro Island, which is a river island that's about the size of Switzerland.
Geological Structures in the Amazon:
The Amazon Craton is located in the northern part of the South American Platform. It represents one of the largest cratonic bodies in the world. It is divided into two shields: Guaporé in the south and Guianas in the north. It's composed of ancient Precambrian fragments.
Threats Facing the Amazon Rainforest
1. Mining- A lot of mining companies want to exploit the hidden resources beneath of the Amazon rainforest. The Amazon basin contains copper, iron ore, gold, nickel, tin, manganese, and other valuable minerals. $27 billon are being invested in mining projects of 2016. The impact of mining, especially the extraction of gold, is very substantial. Extracting gold involves using high concentrations of mercury, which can seep into the environment and poison trees and surrounding areas. Solutions: "Make mining corporations abide by stricter environmental protection laws."
2. Deforestation- Deforestation in the Amazon rainforest has accelerated significantly between 1991 and 2004, though the rate of deforestation has been slowing since 2004. The main causes of deforestation is that they use this rainforest as a resource for cattle pasture, roads, hardwoods, medicines, and housing & farming space. The estimated forest cover in the 1970s was 4,100,000 km squared and in 2015 it was 3,331,065 km squared; 15% of the rainforest has already been destroyed. Logging is also a cause of deforestation. Illegal logging (estimated to be 60-80%) is usually fueled because of the demand fro cheap timber. It clears for cattle ranches & soy plantations, mining, and fuel wood gathering. Solutions: "Increase funding for government protection of the forests and replanting trees, educating the population that forested areas play an important role in stabilizing the climate, storing carbon, producing rainfalls, allowing for the sustainable harvest of forest products, and providing habitat for animals."
3. Commercial Fishing: Fish are one of the main sources of food for Amazonian people. This often leads to over-fishing. This is especially true when large industries harvest fish to export to foreign markets and up to 60% of their catch is lost to spoilage. Solutions: Commercial fishing regulations and set aside reserves.
Organizations Working to Protect the Amazon Rainforest:
- Greenpeace
- Amazon Conservation Association
- Rainforest Action Network
- International Conservation Union (IUCN)
- The Forest Trust
- Rainforest Alliance
- Conservation International (CI)
- Wildlife Conservation Society (WCS)
- World Wildlife Fund for Nature (WWF)
What Actions the Public Can Take to Protect the Amazon:
- Donate and/or volunteer to organizations that work to protect the Amazon.
- Reduce paper and wood consumption- logging companies are cutting down some of the most endangered forests, like the Amazon, in order to make wood and paper products.
- Reduce oil consumption- oil exploration projects lead to toxic pollution and deforestation
Additional Resources:
- http://www.unep.org/vitalforest/Report/VFG-16-The-amazon-the-largest-rainforest-in-the-world.pdf
- http://www.adventure-life.com/amazon/articles/indigenous-people
- http://www.chacha.com/question/what-is-a-example-of-intraspecific-competition-in-the-rain-forest
- http://w3.marietta.edu/~biol/biomes/troprain.htm
- http://rainforests.mongabay.com/amazon/
- http://www.braziltourstravel.com/geology/amazon.htm
- http://www4.ncsu.edu/~dthollom/world_forestry/#2
- http://www.dandc.eu/en/article/endangered-amazon-rainforest
- http://www.softschools.com/facts/wonders_of_the_world/amazon_rainforest_facts/98/
- http://www.adventure-life.com/amazon/articles/what-can-i-do
- http://www.rainforestcruises.com/jungle-blog/threats-facing-the-amazon-rainforest
- http://www.greenpeace.org/international/en/campaigns/forests/amazon/threats-and-solutions/