What is Biodiversity?
All life on earth is part of one great, interdependent system. It interacts
with, and depends on, the non-living components of the planet: atmosphere,
oceans, freshwaters, rocks, and soils. Humanity depends totally on this
community of life - this biosphere - of which we are an integral part.
Biological diversity, or biodiversity, is the variety of the world's
organisms, including their genetic diversity and the assemblages they form.
It is the blanket term for the natural biological wealth that undergirds
human life and well-being. The breadth of the concept reflects the
interrelatedness of genes, species, and ecosystems.
The Value of Biodiversity
The sheer diversity of life is of inestimable value. It provides a
foundation for the continued existence of a healthy planet and our own
well-being. Many biologists now believe that ecosystems rich in diversity
gain greater resilience and are therefore able to recover more readily from
stresses such as drought or human induced habitat degradation. When
ecosystems are diverse, there is a range of pathways for primary production
and ecological processes such as nutrient cycling, so that if one is damaged
or destroyed, an alternative pathway may be used and the ecosystem can
continue functioning at its normal level. If biological diversity is greatly
diminished, the functioning of ecosystems is put at risk.
The many values of biological diversity and its importance for development
indicate why biological diversity conservation differs from traditional
nature conservation. Biological diversity conservation entails a shift from
a reactive posture - protecting nature from the impacts of development - to
a proactive effort seeking to meet peoples' needs from biological resources
while ensuring the long-term ecological sustainability of Earth's biotic
wealth. On a global level it thus involves not only the protection of wild
species and their habitats but also the safeguarding of the genetic
diversity of cultivated and domesticated species and their wild relatives.
The conservation of biological diversity seeks to maintain the life-support
system provided by nature in all its variety, and the living resources
essential for ecologically sustainable development.
Facts About Biodiversity
Tropical forests are a unique and endangered resource. They provide habitat
for millions of plant and animal species, recycle nutrients, protect soils
and watersheds, and provide many products and services to people. These
forests are being cleared rapidly, causing habitat destruction and
extinction of species.
Deforestation threatens biodiversity, a global resource made up of the
variety and variability of life forms on Earth, both wild and domesticated.
State of the Forests
- About one third of the world's land area is covered by forests.
- Just over one half of the world's forests are in developing countries.
- Recent studies by the United Nations Food and Agriculture Organization
indicate the world is losing about 15.4 million hectares (an area four
times the size of Switzerland) of tropical forests each year.
- Causes of deforestation include permanent conversion to agricultural
land; logging; demand for fuelwood, fodder, and other forest products;
grazing; fire; and drought.
- The rate of deforestation is highest in Asia (1.2 percent per year from
1981-90), followed by Latin America (0.8 percent), and Africa (0.7
percent). In the same period, more land was deforested annually in
Latin America and the Carribean (7.4 million hectares) than in Africa
(4.1 million hectares) and the Pacific or Asia (3.9 million hectares).
- Brazil has 30 percent of the world's tropical forests and the largest
area of annual deforestation. The vast majority of trees cleared in the
Amazon region are burned or left to rot when land is cleared for
- Deforestation is second only to burning of fossil fuels as a human
source of carbon dioxide, one of the major greenhouse gases that may
cause the global climate to warm.
- Deforestation leads to soil degradation and destroys habitat, leading
to the extinction of plants, animals, birds, and insects.
State of the World's Habitat and Species
- The habitats richest in biodiversity are the tropical moist forests of
Southeastern Asia, central and west-central Africa, and tropical Latin
America. These forests, described as the global hotspots, contain more
than half of all species.
- At least half of the world's species are contained in just 7 percent of
the world's land surface.
- The exact number of species on Earth is not known. Less than 5 percent
of species in the tropics have been identified. Worldwide, on average,
about three new species of birds are found each year. An estimated 40
percent of freshwater fishes in South America have not yet been
- More than 700 species of vertebrates, invertebrates, and vascular
plants have become extinct since 1600, and untold numbers probably
became extinct without ever being described.
- Only 5 percent of the world's land surface is in national protected
areas. These include nature reserves, national parks and monuments,
habitat and wildlife management areas, and protected landscapes.
- The rate of deforestation is more likely to increase than to stabilize,
although in some areas, there has been dramatic improvement.
- There is growing concern about destruction of the forests, especially
the tropical rainforests.
- Wildlife habitat is threatened by human encroachment and by the
potential threat of climate change.
- The trade in animals and animal products is having devastating effects
on some wildlife populations, such as elephants, parrots, and large
- Global warming would lead to widespread extinctions because habitats
would shift, shrink, or disappear.
Copyright © 1996 Grant Harding. All rights reserved.
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