Tropical Rainforest Vegetationand Structure

Layers of the Forest

• The rainforest is composed of 5 different layers with various plants that have adapted to life in that layer.

• 1. Overstory Layer• 2. Canopy Layer• 3. Understory Layer• 4. The Shrub Layer• 5. Rainforest floor

Canopy Layer

• This layer is believed to be the most bio-diverse of all the rainforest layers and half

of the plant species in the forest are said to be here.

Overstory Layer

• This is the layer of overtopping trees that rise above the rest of the canopy.

• Tops of trees can reach 210 feet• These trees exist in a totally different climate

when compared to the other canopies.• They thrive on a drier environment with

higher winds.• Birds of prey depend on this overstory layer.

Overstory Layer

• The trees are the tallest and are spaced far apart.

• They are adapted to intense sunlight and windy conditions.

• They are straight, have smooth trunks and feature small, reddish leaves that conserve water and reflect sunlight.

• This is sometimes also called the emergent layer

Canopy Layer

• This contains the majority of the rainforests tallest trees

• Light is abundant in this layer• The trees are adapted to intense sunlight and

have small brightly colored leaves.• The leaves have “drip tips” that funnel

rainwater off the leaf and down to the forest below.

Understory Layer

• This layer consists of short trees, shrubs and the trunks of the canopy trees.

• Less than 5% of light coming into the forest reaches the understory layer.

• The leaves of plants here are large and dark to absorb more available light.

• This are of the forest is not dense as there is not enough light to support thick growth.

Understory layer

• This layer is a much less volatile environment than the upper layers.

• Most moisture is retained here• Much of the rainforest’s flora and fauna live

here• There is a large concentration of insects here.

Shrub Layer

• This layer is very closely related to the understory layer.

• This layer is very important botanically.• More than 1400 varieties of tropical plants are

found here.• This is the area of the rainforest where most

medicinal findings have been and where the most hope for future cures are.

Forest Floor

• The final layer of the forest• Less than 2% of incoming light reaches this

layer• Very little vegetation is present• Filled with decaying plant and animal matter

and various forms of fungus and moss.

Rainforest Fauna

• Like plants, rainforests support a large amount of fauna that are all adapted to life in the different layers of the forest.

• Monkey for example live in tropical rainforest canopies, while owls do the same in the temperate rainforests.

• Mammals, reptiles and birds are common throughout the forest.

• Common characteristics found among mammals and birds (and reptiles and amphibians, too) include adaptations to a life in the trees

• Other characteristics are bright colors and sharp patterns, loud vocalizations, and diets heavy on fruits.

• Insects make up the largest single group of animals that live in tropical forests.

• They include brightly colored butterflies, mosquitoes, camouflaged stick insects, and huge colonies of ants.

• The Amazon river basin rainforest contains a wider variety of plant and animal life than any other biome in the world.

• The second largest population of plant and animal life can be found in scattered locations and islands of Southeast Asia

• The lowest variety can be found in Africa.• There may be 40 to 100 different species in

2.5 acres ( 1 hectare) of a tropical rain forest.

Early Explorers….

• When early explorers first discovered the rainforests of Africa, Southeast Asia and South America, they were amazed by the dense growth, trees, vines and shrubs.

• The tropical vegetation grew so dense that it was difficult to cut one's way through it.

• It was thought at the time that the soil of a rainforest must be very fertile, filled with nutrients, enabling it to support the immense trees and other vegetation they found.

Today….

• Today we know that the soil of the tropical rainforests is shallow, very poor in nutrients and almost without soluble minerals.

• Thousands of years of heavy rains have washed away the nutrients in the soil obtained from weathered rocks

• Nutrients generally stay in an ecosystem by being recycled and in a rainforest are mainly found in the living plants and the layers of decomposing leaf litter.

• Various species of decomposers like insects, bacteria, and fungi make quick work of turning dead plant and animal matter into nutrients.

• Plants take up these nutrients the moment they are released.

Fauna

• Tropical rainforests are home to the largest and the smallest, the loudest and the quietest of all land animals, as well as some of the most dangerous, most beautiful, most endearing and strangest looking animals on earth.

• There are so many fascinating animals in tropical rainforests that millions haven't been named or even identified yet.

• In fact, about half of all the earth's animal species live in tropical rainforests.

Why do more animal species live in the rainforest than other parts of the world?

• Scientists believe that there is a great diversity of animals because rainforests are the oldest ecosystems on earth.

• Some rainforests in Southeast Asia have been around for at least 100 million years, when dinosaurs roamed the earth.

• During the Ice Ages, the last of which ended about 10,000 years ago, the frozen areas of the North and South Poles spread over much of the earth, causing a high rate of animal extinction.

• But the giant freeze did not reach a number of refuges in tropical rainforests. Therefore, rainforest plants and animals continued to evolve, developing into the most diverse and complex ecosystems on earth.

• The nearly perfect conditions for life also helped contribute to the great number of species.

• With temperatures constant at 75 -80 F. year-round, animals don't have to worry about freezing during cold winters or finding shade in the hot summers.

• They rarely have to search for water, as rain falls almost every day in tropical rainforests.

• Some rainforest species have populations that number in the millions.

• Other species consist of only a few dozen individuals.

• Living in limited areas, most of these species are endemic, or found nowhere else on earth.

Which type of rainforest species is most numerous?

• If you were to visit a rainforest, you probably wouldn't run into many jaguars or monkeys.

• The only living animals you could be sure to see are the millions of insects creeping and crawling around in every layer of the rainforest.

• Scientists estimate that there are more than 50 million different species of invertebrates living in rainforests.

• One scientist found 50 different species of ants on a single tree in Peru!

How do all these species manage to live together without running out of food?

• Many animals species have developed relationships with each other that benefit both species. Birds and mammal species love to eat the tasty fruits provided by trees. Even fish living in the Amazon River rely on fruits dropped from forest trees. In turn, the fruit trees depend upon these animals to eat their fruit, which helps them to spread their seeds to far-off parts of the forest.

How do rainforest animals protect themselves?

• Every animal has the ability to protect itself from being someone's next meal.

• Each species has evolved with its own set of unique adaptations, ways of helping them to survive.

Is it true that dozens of animal species a day become extinct in tropical rainforests?

• An average of 137 species of life forms are driven into extinction every day in the world's tropical rainforests.

• The forces of destruction such as logging, oil production, and cattle ranching have all contributed to the loss of millions of acres of tropical rainforest.

• When rainforests are destroyed, animals living outside the tropics suffer as well. Songbirds, hummingbirds, warblers and thousands of other North American birds spend their winters in rainforests, returning to the same location year after year. Less return north each spring, as fewer make it through the winter because their habitat has been destroyed.

Extinction

• The cutting down of trees is not the only reason for species extinction. Thousands of monkeys and other primates are traded illegally on the international market each year, wanted for their fur, as pets, or for scientific research.

• Parrots and macaws have also become popular pets; buyers will pay up to $10,000 for one bird.

• Even the king of the jungle, the jaguar, is in danger of becoming extinct. Its fur is highly valued for use on coats and shoes.

• Pollution from mining has killed fish populations in the mighty Amazon River.

• Many Indigenous people, who have depended on these fish for centuries, have become sick from the poisoned fish.

• Today humans are altering their habitats too quickly for animals to adapt.

• So many species become extinct in such a short period of time, that the impact of the industrial age can be compared to the catastrophe of a comet strike on the diversity of life.