Many species of animal life can be found in
the rain forest. Common characteristics found among mammals and birds (and
reptiles and amphibians, too) include adaptations to a life in the trees, such
as the prehensile tails of New
World monkeys. 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.
When early explorers first discovered the
rainforests of Africa, Southeast Asia and South America, they They were amazed
by the dense growth, trees with giant buttresses, vines and epiphytes . 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 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. The rainforest has a very short
nutrient cycle.
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.
A study in the Amazon rainforest found that
99% of nutrients are held in root mats. When a rainforest is burned or cut down
the nutrients are removed from the ecosystem. The soil can only be used for a
very short time before it becomes completely depleted of all
nutrients.
