Biomes in the Tropics and Relationships Within

Biomes are major communities of plants and animals occupying extensive areas of the earth’s surface in response to climatic conditions. Biomes, in turn, contain smaller, more specialized ecosystems: self-contained, self-regulating, and interacting communities adapted to local combinations of climate, topography, soil, and drainage conditions.

As one of the most diverse biomes, tropical rain forest develops naturally in areas of high temperatures and high rainfall and is characterized by the greatest number of species, animal, plant and fungal.

Productivity is high as is the turnover of nutrients, though in many areas the soils are poor in nutrients. In here, many of the mammals are adapted to an arboreal life. The recent exploitation of this biome throughout the tropics is widespread and expanding, particularly in south-east Asia and central South America. Much of this has resulted in the conversion of extensive areas of this biome to a degraded class of forest or, increasingly, to often temporary grassland.

In the tropics, rainforests are often accompanied by aquatic biomes indicated by wetlands and shallow fresh to brackish water biomes, which are among the most productive on the globe, but at the same time are the most threatened because of pollution from industrial, agricultural and domestic activities (Encyclopedia of Ecology and Environmental Management, 1998).

Moreover, Viau (1999) informed that tropical rain forests have been in existence for between 70 million and 100 million years, apparently this biome is very old. During this time the animals and plants have had the opportunity to adapt to each other very closely, and so there are many niches (roles in using a special part of the available resources) that unique organisms fill.

Symbiotic relationships abound, for instance, when bees pollinate special kinds of orchids. As its existence has been gifted for hundred million years of rain, this has affected the soil and when you look at the plant life, it is easy to think that the soil is rich, but it is actually nutrient poor. Plants cannot grow on sunlight and rain alone: they need small quantities of minerals as well.

These minerals include calcium, magnesium, and phosphorus. Over the years the rain has washed these out of the soil, so all the nutrients are actually in the living plants and animals. Thus, there is much competition for the minerals in this type of biome.

For instance, if a leaf falls from a tall tree, or a piece of fruit is knocked off a branch, it may fall to the forest floor. Immediately the detritivores (bacteria and fungi that break down dead material) get to work and start digesting the fallen piece of organic matter (Viau, 1999).

Other animal relationships exist in tropical rain forests: Commensalism (the scavenging mammals, birds, arthropods and others taking share of a wild boar originally killed by a tiger), Mutualism (Ants enter into mutualisms with some homopteran bugs and butterfly caterpillars when the ants provide protection from natural enemies, while feeding on the sugar-rich honeydew the other insects exude) and Parasitism (mosquitoes benefiting through the blood of mammals).

Both the tropical rainforests and its nearby aquatic biomes are threatened by intense deforestation and pollution. Much of the species in these biomes are dwindling because of the human interventions.

The recent exploitation of tropical rainforests is characterized by widespread and expanding, particularly in Southeast Asia and central South America. Much of this has resulted in the conversion of extensive areas of this biome to a degraded class of forest or, increasingly, to often temporary grassland.

Similarly, human activities in the destruction of wetlands includes: drainage for agriculture, mosquito control and flood protection; infilling for waste disposal; mining for gravel; abstraction of groundwater as well as the more insidious effects of eutrophication and pollution from industrial, agricultural and domestic activities.

Added to these are the effects of natural erosion, of changes in sea level and longer-term effects of climate change. Presently, more concern had been given to both biomes and governments have enacted environmental policies to protect the numerous species that exist there.


The Encyclopedia of Ecology and Environmental Management. (1998). Biomes, Major World, Oxford: Blackwell Science.

Viau, E.A. (1999). Tropical Rainforests. World Builders Website, Charter College of Education, California State University. Retrieved 13 April 2006 at