- Up to one-fifth of the world's plant and animal species
could be wiped out within 100 years by deforestation in Southeast Asia,
according to a survey of extinction rates in Singapore(1).
- This bleak prognosis calls for tough conservation measures,
says Barry Brook of the Northern Territory University in Darwin, Australia,
who led the study. "If we don't do anything, things will unfold in
a very unpleasant way," he predicts.
- Tropical rainforests contain a huge and valuable variety
of plants and animals. The encroachment of humans, through deforestation
and urbanization, is homogenizing ecosystems, leaving only a fraction of
species surviving, Brook says.
- Singapore is a case in point. Since British colonization
in 1819, terrestrial and freshwater habitats have shrunk by more than 95%.
Brook's team calculates that this has already extinguished up to 87% of
the island's butterflies, fish, birds and mammals. Hunting wiped out some
of the larger animals. Singapore's last tiger, for example, was shot in
- What's more, many remaining creatures are now too scarce
to recover. Brook's team dubs these species "the living dead".
- "This study confirms that we have a very urgent
problem," agrees Andrew Balmford, who studies conservation strategies
at the University of Cambridge, UK. "Species richness is more sensitive
to habitat loss than was previously thought."
- A small, highly urbanized nation, Singapore probably
represents a worst-case scenario for habitat loss. But its less-developed
neighbours are in danger of inflicting similar damage on their own rainforests.
Malaysia, for example, has already lost 60% of its forests.
- The Singapore survey should influence conservation efforts
throughout the world, Balmford urges. "We need to be concerned about
any region where deforestation is occurring rapidly," he warns.
- This includes Africa, where our inroads into tropical
rainforests have deepened the plight of the great apes. With increasing
human presence comes a worrying escalation in the illegal bushmeat trade.
- Home front
- Conservationists currently recommend that 10-15% of the
Earth's land surface be ring-fenced to preserve its diversity. Given the
ease with which tropical species can be eradicated, this figure may now
have to be increased, Balmford suggests.
- Brook agrees, but stresses that good conservation starts
at home. Of Singapore's remaining plants and animals, more than half dwell
in reserves covering just 0.25% of the island's area. Such fragments are
valuable. The Bukit Timah reserve, for example, covers only ten square
kilometres yet contains as many tree, flower and grass species as Great
- Singapore has no national legislation to protect endangered
ecosystems, but it is a signatory to the United Nations Convention on Biological
Diversity. The agreement came into force in 1993 to protect species-rich
environments such as rainforests.
- References (1) Brook, B. W., Sodhi, N. S. & Ng, P.
K. L. Catastrophic extinctions follow deforestation in Singapore. Nature,
424, 420 - 423, (2003). |Article|
- © Nature News Service / Macmillan Magazines Ltd