Deforestation Could Wipe
Out 1/5 Of All Species

By Michael Hopkin

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 1930.
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 Britain.
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 2003



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