The Rainforest Ecosystem

What is a Rainforest? a tropical woodland with an annual rainfall of at least 100 inches (254 centimeters) and marked by lofty broad-leaved evergreen trees forming a continuous canopy (from Merriam-Webster) Rainforests are the richest, most varied ecosystems in the world Cover just 6% of the earth’s surface, yet contain more than half world’s plant and animal species!

Layers of the Rainforest Rainforest tress grow up to 30 meters high. These are the producers that make food from the sunlight for the inhabitants of the rainforest below. The dense layer of leaves high above the ground is called the canopy. This shades the forest floor from the bright tropical sunshine. Shrubs that grow below the canopy are called the understorey. When dead leaves and branches drop from trees, they fall to the shady, damp forest floor. Here, decomposers feed on plant and animal remains.

Layers of the Rainforest

The Emergent Layer Here, the tallest trees emerge from the canopy. Macaws and butterflies live up here.

The Canopy Here, there is lots of light. There are many leaves and flowers. Howler monkeys, hummingbirds, and toucans live here. At night, bats feed on forest fruit.

The Understorey Here, jaguars climb into low branches and wait, ready to drop onto prey below. Jaguars prey on the tapir. This doesn’t happen on St. Kitts!

The Forest Floor Here, tapirs, spiders, snakes, lizards, and frogs live in the understorey and on the forest floor. Decomposers, such as fungi, worms, millipedes, and bacteria, feed on plant and animal remains.

The Tobago Forest Reserve The Tobago Forest Reserve is the oldest protected forest reserve in the world. In the 18 th century, a scientist called Stephen Hales discovered the link between trees and rainfall. He showed that forest trees circulate water from the soil into the atmosphere by transpiration, and then the water falls again as rain. This explains why the forest environment is so humid. A politician called Soame Jenkyns realized that cutting down all the forest to plant sugar cane could reduce the rainfall and turn Tobago into a desert; so in 1776 a large area of forest was protected.

In-class Activity

What you have learned Copy and complete these sentences using these key words (sustainably, forest floor, rainfall, biodiversity, understorey, canopy): The rainforest ecosystem has greater than any other ecosystem in the world. The tall forest trees grow close together forming a dense high above the. The layer of shrubs and branches beneath the canopy is called the. Transpiration by the forest trees keeps the air humid, producing high. Forests are a valuable resource for human beings, but their wealth must be used.

? Question ? How do the four layers of the rainforest ecosystem, and the plant and animal life they contain, work together to sustain the ecosystem? Who are the producers and consumers?

In-class Assignment Draw a rainforest ecosystem, labeling the forest floor, understorey, canopy, and the emergent layer. Describe some animal species that might be found in the different layers identified in your sketch. Give examples of producers, consumers, and decomposers in a rainforest ecosystem. Explain what part each plays in sustaining the system.