Where Rain Is Always in the Forecast
Tropical rainforests are warm, wet forests
with many tall trees. In most tropical rainforests, it rains every day. Tropical
rainforests grow in a narrow zone near the equator.
They are found in Africa, Asia, Australia, and South and Central America. The
largest rainforest in the world is the Amazon rainforest in South America.
Tropical rainforests are home to a huge number of different plants and animals.
All tropical rainforests are endangered.
Tropical rainforests are found in a narrow region around the equator that
is known as the tropics. The climate is rainy and the temperatures are warm
and nearly the same every day. The sun and the rain combine to create an
environment that is very humid. This climate is ideal for the growth of many
kinds of green plants.
©GLOBIO.org Thirsty Forests
Tropical rainforests are wet nearly all the time. They get lots of rain
all year long, but they also help make rain through evaporation. Tropical
rainforests help regulate weather all over the world.
©G.Ellis/GLOBIO.org Rainforests need lots of water and most of
it comes pouring down as rain - at least 200
cm per year. Some tropical rainforests get more than 3
cm per day! When it is not raining, the leaves are dripping and steam is
rising. This keeps the whole rainforest constantly wet and steamy.
Rainmakers
Rainforest trees are always “sweating” water. One tree might release
over 755
L of water every year. This makes rainforest climates very
different from other environments. In other climates, the water vapor blows
away and later falls as rain in far off areas. But in rainforests half the precipitation comes
from the forests’ own evaporation.
Much of the rain that falls on the rainforest never reaches the ground. It
stays on the trees because the leaves act as umbrellas.
A Many Layered Forest
Tropical rainforests are one of the most
exciting environments to
explore. The rainforest is almost like a giant creature with its own “anatomy.”
Click below and take a look inside.
Something for Everyone
More than half the species on Earth are found in tropical rainforests. Many
species living in these forests have never before been seen or studied by
scientists. Most of these unknown species are insects, like moths.
©G.Ellis/GLOBIO.org Tropical rainforests are important to everyone,
not just to the plants and animals living there. For example, scientists are
always discovering new plants. Some of these plants contain substances that
can be made into medicines.
In addition, tropical rainforests store huge quantities of carbon,
while producing much of the world's oxygen.
Some people call tropical rainforests the lungs of the planet because they
make so much of the oxygen that animals breathe. Another important role tropical
rainforests play is in regulating global weather. They maintain regular rainfall.
They also help prevent floods, droughts, and erosion.
Why So Much Biodiversity?
Although they cover a small area - less than
2% of Earth's surface - rainforests are home to about half the life on Earth.
In fact, tropical rainforests support the greatest biodiversity on
Earth. How do they do it?
- Climate: Tropical rainforests receive almost 12 hours
of sunlight every day. This sunlight is converted to energy by plants through
the process of photosynthesis.
Since there is a lot of sunlight, there is a lot of energy locked up in the
rainforest. This energy is stored in plants that are eaten by animals. Because
there is a lot of food, there are many species of plants and animals.
- Canopy: The spreading structure of the rainforest canopy
means there are more places for plants to grow and animals to live. The canopy
offers many unique sources of food and shelter. For example, there are plants
in the canopy called bromeliads that store water in their leaves. Frogs use
these pockets of water like ponds for hunting and laying their eggs.
Since all their needs are met in the canopy, some frog species spend all
their lives there.
Many different frog species live in the canopy of the rainforest. Most spend
their entire lives in the canopy. They lay their eggs in little pools of
water held in leaves instead of in ponds or streams.
©G.Ellis/GLOBIO.org Plant Life
Rainforest plants have special adaptations.
These adaptations help them survive in the special climate of a tropical rainforest.
For example, many trees have buttress and prop roots
for extra support in the thin rainforest soil.
Waterways to the Roots
Plant leaves have drip
tips and grooves or waxy coatings to shed water. This allows the water
to fall straight down to the plant’s own roots.
Soaking Up the Sun
Tropical rainforest plants have many adaptations for living in the forest.
Some collect all their water from the air. For this reason, many of them
have very large leaves. Others have flexible stems that allow them to bend
and follow the sunlight so they can carry out photosynthesis all day.
©G.Ellis/GLOBIO.org To absorb as much sunlight as possible in the shady understory,
most leaves are very large. Some trees have flexible leaf stalks that rotate
to follow the sun.
This helps them get the maximum amount of light. Some trees grow larger leaves
in the lower canopy level and smaller leaves in the upper canopy. Other plants
grow in the upper canopy on larger trees. This helps them get closer to the
sunlight. These types of plants are called epiphytes.
Orchids and bromeliads are epiphytes.
Animal Life
Animal species in the rainforest also have
many adaptations to life in the trees. For example, prehensile tails
are common on possums, new world monkeys, and some reptiles. Special flaps
of skin help some lizards and frogs glide between treetops.
The Insect Army: Now You See Them, Now You Don’t
Insects make up the largest single group of animals that live in tropical
rainforests. Ants form huge colonies, often over one million! Many butterflies
and other insects have bright colors and strong patterns. This helps them find
mates. Others have markings that camouflage them
so well it is almost impossible to see them.
Tropical Rainforests and People
Some traditional rainforest cultures still live in the forests. They travel
as a group to collect and hunt food. As rainforests are destroyed, so are
the homes of these interesting and amazing people.
©G.Ellis/GLOBIO.org People have lived in and around tropical
rainforests for many thousands of years. During most of that time, the relationship
worked well. Forest people cut small amounts of the rainforest to build their
homes and to burn as firewood. They used plants as medicine and food. These indigenous people
were semi-nomadic, which means they moved their villages when they needed to
find new food supplies or to find higher ground during floods.
Vanishing Rainforest Cultures
Today, a few of these rainforest cultures still live in West Africa, Borneo,
and the Amazon. Life is changing very rapidly for rainforest people. Roads
are often built through the rainforest for oil and gas exploration, logging,
and mining. These roads and development often chop up the traditional homelands
of the local cultures. Outside people also bring diseases like
colds, pneumonia, and measles. All these things are endangering the culture
of the rainforest peoples.
Rich Biodiversity, Poor Soil
When explorers first entered the world’s
rainforests, they were amazed by the rich growth of plants, giant trees, dangling
vines, and epiphytes. They thought the soil of a rainforest must be very rich.
They tried cutting the forest and turning it into farmland. It didn’t
work. When a rainforest is burned or cut down, the soil can only be used for
a very short time before it runs out of nutrients.
Afterward, biodiversity suffers.
Decomposers like leaf-cutter ants, termites, bacteria, and fungi live on
the forest floor. These decomposers quickly turn fallen leaves and dead organisms
into nutrients. This creates food for trees and other plants and animals.
©C.Ziegler/GLOBIO.org Today, we know that the soil of the tropical rainforests is thin and very
low in nutrients. Decomposers like leaf-cutter ants, termites, bacteria,
and fungi quickly
turn falling leaves and dead organisms into
nutrients. Plants take up these nutrients the moment they are available, so
they don’t get a chance to enrich the soil.
Keeping Tropical Rainforests Healthy
Conservation of
tropical rainforests should be easy. They have survived for millions of years.
The trick to keeping them healthy is to not take too much too fast. This gives
the rainforests time to recover from human activities like logging. But many
countries that have tropical rainforests are poor. They can make money by cutting
down and developing the rainforests. But uncontrolled development results in deforestation,
erosion, and loss of biodiversity.
Carving up the Forests
Roads are cut through previously untouched rainforest to make way for logging
trucks, mining equipment, and farm machines. These roads cut forest habitat
into small pieces. This isolates the animals in those areas, which makes
it harder for them to travel and find mates.
©G.Ellis/GLOBIO.org One of the most damaging effects of development has been dividing the rainforest
habitat into little patches of forest. This is called fragmentation.
Today, many species are isolated in these small areas of forest because they
will not or cannot enter open habitats. The result is that species such as orangutans cannot
connect with one another to mate and
have babies.
Conservations Efforts
More research and strong conservation are the best tools for protecting the
tropical rainforest. Instead of cutting the forests, some people take visitors
on hikes in the forests, which is part of a conservation effort known as ecotourism.
People also are trying to help wildlife survive by creating protected areas
and rehabilitation centers.
Tropical Trivia
- Rainforests have 170,000 of the world's 400,000 known plant species.
- The United States has 81 species of frogs, while Madagascar (which is smaller
than Texas) may have 300 species.
- Europe has 321 butterfly species, while Manu National Park in the tropical
rainforest of Peru has 1,300 species!
- The world’s only species of flying snake and lizard live in the Borneo
rainforest.
- The largest catfish in the world lives in a tropical rainforest river in
Vietnam. It weighs over 300
kg.
- About one-quarter of all the medicines we use come from rainforest plants.
- Curare comes from a tropical vine. It is used as an anesthetic and
to relax muscles during heart surgery.
- Quinine, from the cinchona tree, is used to treat malaria.
- A person with leukemia has a 99% chance that the disease will go into remission because
of the rosy periwinkle.
- More than 1,400 varieties of tropical plants might be potential cures
for cancer.