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Window on a world of vanishing species
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This Thisweek– week– Biodiversity– PETER ALDHOUS AND DEBORA MACKENZIE
Windows on a vanishing world Prospects for the world’s mammals appear as grim as ever, but a novel census method is revealing how other less prominent groups of species are faring
THE world’s mammals are in crisis, with about 1 in 5 species threatened with extinction. That is the bleak headline news from the latest revision of the IUCN Red List of Threatened Species, released on 6 October. But one bright spot in this gloomy picture is that biologists have acquired a powerful new tool for discovering whether other groups of plants and animals are faring any better. Called the Sampled Red List Index, it provides a snapshot of the conservation status of groups of animals or plants – much as financial indices such as the Dow Jones allow investors to monitor
“Some groups of invertebrates and plants contain so many species that a comprehensive survey is virtually impossible”
MASA USHIODA/SEAPICS
the health of the stock market by tracking a selection of publicly traded companies. The grim news that 1141 of 5487 mammals could disappear from the planet comes from an assessment of the conservation status of all known species (Science, DOI: 10.1126/science. 1165115). Similar assessments exist for birds and amphibians. The threats to mammals are well known: marine mammals are at risk from pollution and fishing, and land mammals from habitat destruction and hunting, especially in south and south-east Asia, where 80 per cent of primates are threatened. Conservation needs to be about more than fur, feathers and frogs, however. The vast majority of Earth’s biodiversity lies in other groups, and for many of these the threats are poorly understood. The International Union for Conservation of Nature (IUCN) estimates that the status of fewer than 2.5 per cent of all known species of plants and animals has been assessed so far. As a result, conservationists are being forced –Humpback whales are easy to count; other species less so– to set their priorities without 6 | NewScientist | 11 October 2008
www.newscientist.com
In this section ● Verdict on controversial stem cell paper, page 9 ● Non-invasive test for Down’s syndrome, page 10 ● Obama vs McCain on climate, page 12
TASMANIAN DEVIL The population of this carnivorous marsupial has fallen by more than 60 per cent over the past decade because of a fatal infectious face cancer
WAYNE VAN DEUENDER JUNIORS BILDARCHIV/OSF DAVID HEWETT KARL AMMANN/NATUREPL.COM
ARABIAN ORYX The oryx has just been downlisted from endangered to vulnerable because numbers in Israel and Saudi Arabia are increasing
HOLDRIDGE’S TOAD Recently declared extinct, the toad is thought to have been affected by the fungal disease chytridiomycosis, which has devastated amphibian populations worldwide
www.newscientist.com
NUMBER OF MAMMALS ON EARTH
5487
1141
NUMBER THREATENED WITH EXTINCTION
BECOMING MORE ENDANGERED
BECOMING LESS ENDANGERED
OF LEAST CONCERN
AFRICAN ELEPHANT While poaching still threatens the elephants, successful conservation efforts in southern and eastern Africa have kept numbers up
IUCN RED LIST 2008 We know most about the status of mammals and a few prominent species from other groups
Tasmanian devil
Humpback whale
NEAR THREATENED
GOING, GOING, GONE
Samples of this size can be assessed more quickly and cheaply than the comprehensive surveys done for mammals, birds and amphibians – which can take five or more years to complete and cost millions of dollars. Baillie says that it would in any case be virtually impossible to make a comprehensive assessment of some groups of invertebrates and plants because they contain so many species. The first sampled indices were released at the World Conservation Congress in Barcelona, Spain, this week. They reveal that at least 16 per cent of freshwater crabs, and a minimum of 9 per cent of dragonflies and damselflies, are threatened with extinction. Indices for several more groups of invertebrates – including butterflies, dung beetles and freshwater molluscs – should follow by 2010. So too should an index for the monocotyledons, a major group of flowering plants that includes grasses and orchids. “That will take us out of the conservation dark ages,” says Baillie. One result will be to overcome the geographical patchiness of information on some important groups of plants and animals, which has led to biased views of the global threats facing them. For instance, freshwater bivalve molluscs have been extensively studied in North America, where 77 per cent of species are threatened with extinction or have already been lost. Elsewhere in the world, they are thought to be in better shape, says Mary Seddon of the National Museum Wales in Cardiff, UK, who chairs the Mollusc Specialist Group of the IUCN’s Species Survival Commission. The indices’ main value will emerge as they are recalculated every few years, revealing trends in species survival. But as with the stock market indices, on which his assessment technique was loosely based, Baillie fears that the news won’t be good. “It will be very similar to what we’ve seen on the financial markets in the past few weeks,” he predicts. ●
African elephant Fishing cat Caspian seal Cuban crocodile
Iberian lynx
CRITICALLY ENDANGERED, ENDANGERED and VULNERABLE
crunched the numbers for birds and amphibians: this shows that it is possible to get a reliable picture of the conservation status of a group of species as a whole by assessing the status of 900 selected at random (Conservation Letters, vol 1, p 18). As good information may be unobtainable in practice for up to 40 per cent of species, the team recommends a sample of 1500 to obtain enough data.
Rameshwaram parachute spider
Indian rhinoceros
Arabian oryx Przewalski's gazelle
Walia Ibex
Little Earth hutia
Père David's deer EXTINCT or EXTINCT IN WILD
having all the facts. “People take educated guesses, but there’s no way to say whether insects are doing better or worse than birds,” says Peter Kareiva, chief scientist with the US-based conservation organisation The Nature Conservancy. This is where the Sampled Red List Index comes in. A team led by Jonathan Baillie of the Zoological Society of London, working on an IUCN project, has
Holdridge’s toad
Wild horse
Black-footed ferret
11 October 2008 | NewScientist | 7
This Thisweek– week– Biodiversity– PETER ALDHOUS AND DEBORA MACKENZIE
Windows on a vanishing world Prospects for the world’s mammals appear as grim as ever, but a novel census method is revealing how other less prominent groups of species are faring
THE world’s mammals are in crisis, with about 1 in 5 species threatened with extinction. That is the bleak headline news from the latest revision of the IUCN Red List of Threatened Species, released on 6 October. But one bright spot in this gloomy picture is that biologists have acquired a powerful new tool for discovering whether other groups of plants and animals are faring any better. Called the Sampled Red List Index, it provides a snapshot of the conservation status of groups of animals or plants – much as financial indices such as the Dow Jones allow investors to monitor
“Some groups of invertebrates and plants contain so many species that a comprehensive survey is virtually impossible”
MASA USHIODA/SEAPICS
the health of the stock market by tracking a selection of publicly traded companies. The grim news that 1141 of 5487 mammals could disappear from the planet comes from an assessment of the conservation status of all known species (Science, DOI: 10.1126/science. 1165115). Similar assessments exist for birds and amphibians. The threats to mammals are well known: marine mammals are at risk from pollution and fishing, and land mammals from habitat destruction and hunting, especially in south and south-east Asia, where 80 per cent of primates are threatened. Conservation needs to be about more than fur, feathers and frogs, however. The vast majority of Earth’s biodiversity lies in other groups, and for many of these the threats are poorly understood. The International Union for Conservation of Nature (IUCN) estimates that the status of fewer than 2.5 per cent of all known species of plants and animals has been assessed so far. As a result, conservationists are being forced –Humpback whales are easy to count; other species less so– to set their priorities without 6 | NewScientist | 11 October 2008
www.newscientist.com
In this section ● Verdict on controversial stem cell paper, page 9 ● Non-invasive test for Down’s syndrome, page 10 ● Obama vs McCain on climate, page 12
TASMANIAN DEVIL The population of this carnivorous marsupial has fallen by more than 60 per cent over the past decade because of a fatal infectious face cancer
WAYNE VAN DEUENDER JUNIORS BILDARCHIV/OSF DAVID HEWETT KARL AMMANN/NATUREPL.COM
ARABIAN ORYX The oryx has just been downlisted from endangered to vulnerable because numbers in Israel and Saudi Arabia are increasing
HOLDRIDGE’S TOAD Recently declared extinct, the toad is thought to have been affected by the fungal disease chytridiomycosis, which has devastated amphibian populations worldwide
www.newscientist.com
NUMBER OF MAMMALS ON EARTH
5487
1141
NUMBER THREATENED WITH EXTINCTION
BECOMING MORE ENDANGERED
BECOMING LESS ENDANGERED
OF LEAST CONCERN
AFRICAN ELEPHANT While poaching still threatens the elephants, successful conservation efforts in southern and eastern Africa have kept numbers up
IUCN RED LIST 2008 We know most about the status of mammals and a few prominent species from other groups
Tasmanian devil
Humpback whale
NEAR THREATENED
GOING, GOING, GONE
Samples of this size can be assessed more quickly and cheaply than the comprehensive surveys done for mammals, birds and amphibians – which can take five or more years to complete and cost millions of dollars. Baillie says that it would in any case be virtually impossible to make a comprehensive assessment of some groups of invertebrates and plants because they contain so many species. The first sampled indices were released at the World Conservation Congress in Barcelona, Spain, this week. They reveal that at least 16 per cent of freshwater crabs, and a minimum of 9 per cent of dragonflies and damselflies, are threatened with extinction. Indices for several more groups of invertebrates – including butterflies, dung beetles and freshwater molluscs – should follow by 2010. So too should an index for the monocotyledons, a major group of flowering plants that includes grasses and orchids. “That will take us out of the conservation dark ages,” says Baillie. One result will be to overcome the geographical patchiness of information on some important groups of plants and animals, which has led to biased views of the global threats facing them. For instance, freshwater bivalve molluscs have been extensively studied in North America, where 77 per cent of species are threatened with extinction or have already been lost. Elsewhere in the world, they are thought to be in better shape, says Mary Seddon of the National Museum Wales in Cardiff, UK, who chairs the Mollusc Specialist Group of the IUCN’s Species Survival Commission. The indices’ main value will emerge as they are recalculated every few years, revealing trends in species survival. But as with the stock market indices, on which his assessment technique was loosely based, Baillie fears that the news won’t be good. “It will be very similar to what we’ve seen on the financial markets in the past few weeks,” he predicts. ●
African elephant Fishing cat Caspian seal Cuban crocodile
Iberian lynx
CRITICALLY ENDANGERED, ENDANGERED and VULNERABLE
crunched the numbers for birds and amphibians: this shows that it is possible to get a reliable picture of the conservation status of a group of species as a whole by assessing the status of 900 selected at random (Conservation Letters, vol 1, p 18). As good information may be unobtainable in practice for up to 40 per cent of species, the team recommends a sample of 1500 to obtain enough data.
Rameshwaram parachute spider
Indian rhinoceros
Arabian oryx Przewalski's gazelle
Walia Ibex
Little Earth hutia
Père David's deer EXTINCT or EXTINCT IN WILD
having all the facts. “People take educated guesses, but there’s no way to say whether insects are doing better or worse than birds,” says Peter Kareiva, chief scientist with the US-based conservation organisation The Nature Conservancy. This is where the Sampled Red List Index comes in. A team led by Jonathan Baillie of the Zoological Society of London, working on an IUCN project, has
Holdridge’s toad
Wild horse
Black-footed ferret
11 October 2008 | NewScientist | 7