Rainforest – Center of Biodiersity

Overview

Rainforest can be defined as tall dense forests with high amounts of annual rainfall. The reason it is called a “rain” forest is because of the high amount of rainfall it gets per year.  The climate of a rain forest is very hot and humid so the animals and plants that exist there must learn to adapt to this climate.

The rainforest is nearly self-watering. Plants in rainforest release water into the atmosphere through a process called transpiration. In the tropics, each canopy tree can release about 200 gallons (760 liters) of water each year. The moisture helps create the thick cloud cover that hangs over most rain forests. Even when not raining, these clouds keep the rain forest humid and warm.

There are two types of rainforest: tropical and temperate. Tropical Rainforest is often located between the Tropic of Capricorn and the Tropic of Cancer.  It is spread in Brazil and northern South America, West Central Africa, India and Southeast Asia, Indonesia, and Northeast Australia. 

Temperate Rainforests are located in several regions across the  world including the Pacific Coast of the United States and Canada, and various regions of Europe, Russia and Eastern Asia. 

Temperate Rainforest may often have more coniferous trees such as pines, firs and redwoods; whereas Tropical Rainforest contains more broad-leafed trees. 

In 1917, the rainforest was described by naturalist William Beebe: “Yet another continent of life remains to be discovered, not upon the earth, but one to two hundred feet above it, extending over thousands of square miles … there awaits a rich harvest for the naturalist who overcomes the obstacles—gravitation, ants, thorns, rotten trunks— and mounts to the summits of the jungle trees.”

Layers of the Rainforest

Emergent Layer

Emergent trees grow far apart and tall, their branches reaching above the rainforest canopy.  These trees can grow to heights of 200 feet or more.  Emergent trees do not generally grow close to one another, and will endure different conditions than other trees of the rainforest.  They will receive more

sunlight and less moisture because they are not confined to the shady and humid conditions that exist beneath the rainforest canopy.  Animals that inhabit emergent trees include a variety of insects, some species of bats and and some species of birds including Harpy Eagles.

Canopy

The rainforest canopy is composed of trees that grow to heights between 100 – 150 feet. 

The upper canopy are houses for most of the rainforest animals species, and forms a roof that blocks most light from reaching below it. 

Animals that inhabit the rainforest canopy include Lemurs, Spider Monkeys, Sloths, Toucans, Orangutans and Parrots.  Some of these animals find most or all of their food high in the trees of the canopy so that they will rarely, if ever, need to go to forest floor. The canopy also acts as a reverse umbrella for the rainforest.  It traps moisture and humidity underneath the leaves of its trees and also blocks out sunlight.

Understory

The understory is the layer of the rainforest between the canopy and the forest floor.  The understory, usually shaded and home to bushes and shrubs as well as the branches of canopy trees. Here, the leaves of trees and plants are broad and large so that they can capture what little light gets through the canopy.  The understory is dark and humid, and has a large amount of insect life.

Rainforest Floor – The forest floor is in complete shade, meaning there is little likelihood of plants growing there and making it easy to walk through the forest. The rainforest floor only receives between 1 – 2% of the sunlight that hits the upper layers of the rainforest. 

Very little plant life grows here as a result.  Although the ground is covered by a layer of decomposing vegetation,  the top soil is surprisingly poor in nutrients.  The rainforest floor is very humid due to the evaporation of water from the leaves and shrubs that are found in this layer.  This humidity will help speed up the process of decomposition of the matter.  A wide variety of life including insects and larger animals inhabits the rainforest floor.  Some of the larger animals that live in this layer include

Jaguars, Bengal Tigers, Okapis, and Southern Cassowaries.

Life in the Rainforest

It is believed that over 50% of the world’s species of plants and animals are found in the rainforest.  As many as 30 million species of plants and animals live in tropical rainforests. At least two-thirds of the world’s plant species, including many exotic and beautiful flowers grow in the rainforests. Amazingly, only cover 6 – 7% of the total land surface on Earth is covered by rainforest. 

On average, there are between 20 to 80 different species of trees per acre. Plants in the rainforest ecosystem grow very close together and contend with the constant threat of insect predators. They have adapted by making chemicals that researchers have found useful as medicines.

Bioprospecting, or going into the rain forest in search of plants that can be used in foods, cosmetics, and  medicines, has become big business during the past decade, and the amount that native communities are compensated for this varies from almost nothing to a share in later profits.

There is also a wide variety of animal life found in the rainforest.  Many of the animals have special adaptations that allow them to live in the tropical conditions, but they would not survive outside of this ecosystem.  These animals include but are not limited to Toucans, Parrots, Resplendant Quetzals,

Sloths, Orangutans, Gorillas, Queen Alexandra Birdwing Butterflies, and Lemurs.

There are also indigenous cultures of people that live in and depend on the rainforest.  Some of the tribes that can be found here include the Yanomami and Kayapo tribes of the Amazon, the Huli of Papau New Guinea, and the Pygmies of Central Africa.  Some tribes have had little, if any, contact with outside

civilizations, while others seek to legally protect the lands on which they live.  These cultures have adapted to the conditions of the rainforest, and have a deep understanding of the ecosystem.  They often have knowledge of medicinal herbs and plants, and understand how to cultivate rainforest land without upsetting the balance of nutrients in the soils.

Deforestation

Much of the world’s rainforest has been severely impacted by human activities.  These activities usually include deforestation for the purposes of logging, growing crops, urban settlement, or raising farm animals such as cattle.  As the population of the world continues to increase, the amount of deforestation of the rainforest may also continue to rise.

Unfortunately, we are losing many species of plants and  animals found in the ecosystem due to these activities.  Potential medicines that have not even been discovered yet may be at risk of never being found due to deforestation.  Many rainforest animals are endangered due to these activities.  Cultures of indigenous peoples are also at risk of losing their way of life.

There are currently many organizations working to protect the rainforest.  Some of them include the Rainforest Alliance, The Nature Conservancy, and the Rainforest Action Network.  These sites provide information on ways we can all help to conserve one of the world’s most valuable and endangered ecosystems.

Many trees and plants, like orchids, have been removed from the rain forest and cultivated. Brazil nut trees are one valuable tree that refuses to grow anywhere but in undisturbed sections of the Amazon rain forest. There, it is pollinated by bees that also visit orchids, and its seeds are spread by the agouti, a small tree mammal.

Summary

The rainforest is a vital lifeline of Earth, as well as one of the most unique ecosystems of our planet.  It contains a wide variety of plants, animals and people, and all are important to the balance of nature.  While it is not too late to save the rainforest ecosystems of the world, there is still much work to be done if we will succeed in protecting this valuable resource.

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