RAINFOREST DIVERSITY - ORIGINS AND IMPLICATIONS
Tropical rainforests support the greatest diversity of living organisms on Earth.
Although they cover less than 2 percent of Earth's surface, rainforests house an estimated 50 percent of all life on the planet's land masses.
No one knows exactly how many species live in the world's tropical rainforests — estimates range from 3 to 50 million species — rainforests are the undisputed champions of biodiversity among the world's ecosystems, containing far higher numbers of species on a per-area basis relative to sub-tropical, temperate, and boreal ecosystems. For example, whereas temperate
forests are often dominated by a half dozen tree species or
fewer that make up 90 percent of the trees in
the forest, a tropical rainforest may have more than 480 tree species
in a single hectare (2.5 acres). A single bush in the Amazon may have
more species of ants than the entire British Isles. This diversity of
rainforests is not a haphazard event, but is the result of a series
of unique circumstances.
Comparison of biodiversity for selected groups between the United States and Indonesia
What is biodiversity?
Biodiversity -- short for biological diversity -- is the the number and types of organisms in an habitat, ecosystem, region or environment. It can refer to genetic, species, or habitat variation at any scale.
Portraits of Diversity
Countries with the Highest Biodiversity
Leaf-tailed gecko in the rainforest of Madagascar. (Photo by R. Butler)
- Most of the plant and animal species live in what level of the rainforest?
- What are epiphytes?
- What is an example of an epiphyte? (Hint: think of a popular kind of flower)
- What are lianas?
- What is a symbiotic relationship?
- What is a keystone species?
- Why are agoutis important in the rainforest ecosystem?
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Continued / Next: Role of Climate, Solar Energy, and Stability
The opening quotation comes from The Song of the Dodo (New York: Scribner, 1996) by David Quammen.
In his The Diversity of Life (Cambridge, Mass.: Belknap Press, 1992), E.O. Wilson eloquently depicts rainforest diversity using the example of the number of ants in a bush: a single bush in the bush in the Amazon may have more species of ants than the entire British Isles.
The "Mean Net Primary Production by Ecosystem" table is derived from Holdgate, M. ("The Ecological Significance of Biological Diversity," Ambio Vol. 25, No. 6, Sept. 1996).
E.O. Wilson demonstrates the Increase in Diversity Towards the Tropics using the number of bird species in locations of similar size (The Diversity of Life, Cambridge, Mass.: Belknap Press, 1992).
The box, "Portraits of Rainforest Diversity" is derived from several sources: plant species (E.O. Wilson, The Diversity of Life, Cambridge, Mass.: Belknap Press, 1992); butterflies (Robbins, R.K. and Opler, P.A., "Butterfly Diversity and a Preliminary Comparison with Bird and Mammal Diversity," p 69-75 in Biodiversity II. Reaka-Kudla, Wilson, Wilson, eds., Joseph Henry Press, Washington D. C. 1997); and insects (Didham, R.K. and Stork, N.E., "Rise of the Supertramp Beetles," Natural History, Vol. 107, No. 6. July/August 1998).