Tropical Rainforest Biome: Plants and Animals

All is still. Mystery permeates through the olive dark forest. The twilight effect, caused by gathering clouds and the forest canopy, deepens the mystery. The vegetation, shrouded by swirling mist, takes on a wraith-like appearance. It is as if Mother Nature, clad in her verdant robes, is lost in a reverie. A snake slithers unseen in the undergrowth. A puma stands ready to pounce in the shadowy depths. Suddenly, the high screeches of a flock of brightly hued parrots shatter the reverie.

The tropical rainforest – whether the jungles of Africa, the forests of Borneo, or the mile-upon-mile leafy canopies of the Amazon – is aptly named. During the rainy season, on most afternoons, the rain clouds start accumulating and the humidity heightens until finally the thunder’s growls erupt into roars, the wind rises into a shriek and the rain begins crackling on the leaves. In the areas where tree-cover is sparse, the heavy big drops are heard long before thick sheets of water thrust their way to the forest floor. The sound can be so loud that it can even be hard to hear yourself think as the drops slosh on to the forest floor. But the forest’s leafy canopy turns into an umbrella, softening the force of the rain, its path downward constantly being re-routed as the drops run off the glossy green leaves.

When night befalls, the rainforest is shrouded in pitch darkness. The moon and the bright stars are veiled by layer upon layer of leaves. But it is no longer silent, being filled with the orchestra of forest sounds made up of chirruping insects, hooting night birds, croaking frogs, and the whispering swish of the wings of flying foxes. It is at this time that the tropical rainforest is at its most fascinating.

The extraordinary manner in which the rainforest, and all the life that it supports, function is equally fascinating. The soil on which tropical forests are found is very poor and shallow. In order to overcome this, nature has perfected amazing recycling methods. In the rainforests this recycling can be seen taking place right in front of your eyes as the humid heat decays everything faster. If you should finger a fallen log you will find loose, softened wafers of the wood breaking off. And while it decays, throngs of organisms like fungi and insects, feast on the nutrients.

Only a small portion of tropical forests is considered as rainforests. In order to qualify as a rainforest, the area must have the following criteria:

• Forests that exist between the Tropic of Cancer and Tropic of Capricorn.
• Forests that stay frost free and warm throughout the year, with the mean temperature being between 70 degrees and 85 degrees F, with minimal daily fluctuation.
• Forests that receive regular rainfall all through the year, about 80 to 400 inches per year.

Therefore, much of the tropical forested areas are not considered rainforests. Those forests that get irregular rains, e.g., monsoon rains succeeded by a dry season, are moisture laden deciduous forests. The trees that exist in these forests usually shed their leaves during the dry season.

Tropical Rainforest Biomes Have Four Strata:

Scientists have divided the rainforest into four zones, or strata, on the basis of the living environment. Different plants and animals dwell in these zones.

The Emergent Layer

This layer comprises of giant trees that thrust up higher than the layer of dense canopy, forming huge crowns shaped like mushrooms. Although these trees get the highest amount of sunlight, they are also subject to strong winds, low humidity, and high temperatures. This layer is home to many insects and birds.

The Canopy Layer

The irregular, broad crowns of the trees in this layer form a continuous, tight canopy, which is about 60-90 feet above the forest floor. The branches of these trees are usually entangled with liana vines and covered with epiphytes. The canopy is where 90 percent of the organisms of the rainforest can be found, most of them seeking the treetops for the brighter light there. These include mammals, reptiles, birds, insects, and so on.

The Understory

This layer is a dark and cool place because it receives only 2 to 15 percent of the sunlight that falls on the canopy. It is a comparatively open space, containing leafy herbaceous plants and young trees that can only tolerate low light. Most of the popular house plants that people buy to decorate their gardens and homes come from here.

The Forest Floor

The floor of the forest gets less than 2 percent of the sunlight; hence little grows here apart from plants that are adapted to very low amounts of light. The floor of the forest is covered with a thin layer of branches, leaves, fruits, and seeds, which decompose very quickly. It teems with animal life, particularly insects. The largest animals that inhabit the rainforest populate this area.

Adaptations in Tropical Rainforests

Usually getting over 80 inches of rain per year, the rainforest plants have made adaptations, which help them to shed water in an efficient manner. For example, many plants that exist in rainforests have leaves that have drip tips, precisely for this purpose. Since these trees grow in wet, spongy soils, they also have stilt and buttress roots, which provide extra support.

Another interesting adaptation that the plants have is the ability to absorb as much of the little sunlight that comes through to the forest floor. Hence, it’s common for these plants to have large leaves, which increase their capacity to take in sunlight. Some plants, such as ferns, bromeliads, and orchids grow as epiphytes up in the canopy, where there is more sunlight available. These plants usually get their nourishment from the air itself through their ‘air roots’. This is possible due to the high humidity in these areas.

What Makes the Tropical Rainforest Biome Special?

• The tropical rainforests are where half of the Earth’s animal and plant species exist.
• Many birds that breed in temperate zones make them their winter home.
• Some of the most beautiful wildernesses on Earth are found in tropical rainforests.
• The forests abound with medicinal plants that are beneficial for us.
• Many unique tribal cultures have inhabited these forests for thousands of years.
• Tropical rainforests help to maintain the global weather and rain patterns. A large part of the water that evaporates from the plants comes back as rain. Hence, the destruction of this important ecosystem can affect rainfall patterns adversely.
• The ecosystem of the tropical rainforest biome consists of one of the most complex interdependence of animals and plants. Although this is its main strength, it can also be its weakness; organisms that are highly specialized are especially susceptible to disturbance, since they do not have the ability to adapt quickly enough to survive any changes that may occur.
• Of the estimated 250,000 species of plants that exist on earth, about 160,000 comprise of tropical plants.

The Myriad Animals of the Rainforests

The tropical rainforest biome is inhabited by some of the most beautiful and strangest of animals in all their myriad variety, from the largest to the smallest, the loudest to the quietest, the most dangerous to the mildest. For example, a species of frog that can fly, a rabbit sized antelope, a spider species that eats birds. Some of the other animals that live in this habitat are toucans, jaguars, tarantulas, and gorillas. And have you heard of the okapi? Or the aye-aye? The okapi looks like a giraffe, but is smaller with a far shorter neck and has stripes on its legs. The aye-aye is a nocturnal animal, closely related to lemurs, which has rodent-like incisor teeth and long bony fingers. In fact, there are such a vast variety of animals in the tropical rainforests that many have not been identified or named yet.

There is large-scale destruction of the tropical rainforest habitats of the world going on even as you read this, due to development and logging. Hence, many of these unique species of plants and animals are endangered, while many have already become extinct. Some of the endangered rainforest animals are the orangutan, jaguar, harpy eagle, chimpanzee, golden lion tamarind monkey, gorillas, toucans, parrots, and many more. Once these beautiful creatures disappear, no longer will the Earth resound with the beautiful orchestra of forest sounds.