STATE OF THE RAINFOREST 2014
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The two countries with the greatest diversity of mammals are among
the world’s largest rainforest countries, Indonesia (670 species)
and Brazil (648 species). According to an analysis by the IUCN
Red List,
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Indonesia is also the country with the highest number of
threatened mammals in the world. The fact that new species are still
being discovered is a clear indication of the vast and unmapped
biodiversity in the world’s rainforests.
Why are there so many species?
In general, the diversity of plants and animals increases dramatically
from the polar regions to the tropics. But we do not yet know why
rainforests are so exceptionally rich in biodiversity. Is it due to inter-
species struggle for specialization? Or is it a matter of the gradual
accumulation of species under relatively stable tropical forest conditions
over millions of years? Other theories hold that species evolve more
rapidly in warm climates; that variations in micro-climate and periods
where pockets of rainforest have been isolated in a drier or colder
climate have fostered diversity; or that the geological changes that
elevated lowlands to mountains (like the Andes) have stimulated the
huge variety of plants and animals. The many theories are not mutually
exclusive.
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Probably, all these factors have been involved in shaping
the rich diversity of the world’s rainforests as we know them today.
Human beings have also played a part in the interaction. In the
Amazon there are traces of hunter-gatherer societies dating some
9000 years back, and of agricultural societies existing 4500 years
ago. Human life has also been documented in the rainforests
of Africa and Asia
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dating several thousand years back in time.
While species extinction thousands of years ago has been linked
to human activity in some places, human activity is not necessarily
synonymous with destruction. There are also signs that people, in
the interaction with their environment, have actually strengthened
species diversity. Wemay need to re-adjust our notions of rainforests
as primeval, virgin tracts untouched by humans.
Disappearing diversity
The last time the golden toad (
Incilius periglenes
) was seen, was
in a nature reserve in Costa Rica in 1989. The species of our planet
Vietnam
Russian
Federation
Democratic
Republic
of the
Congo
Papua
New Guinea
Thailand
Costa
Rica
Malaysia
Philippines
Australia
Bolivia
Argentina
Peru
India
Tanzania
Madagascar
United
States
Ecuador
Venezuela
South
Africa
Mexico
Indonesia
China
Colombia
Brazil
Rainforest country
Biodiversity is concentrated in the rainforest
Total number of amphibian,
bird, mammal, reptile, and
vascular plant species
NB: Only values above 10 000 are shown
60 000
25 000
10 000
Source: Mongabay.com
