THE struggle to preserve the world鈥檚 biodiversity is being compromised by
fatal flaws in the way conservationists draw up their lists of endangered
species.
An Australian botanist warns that the lists reflect the plants and animals
that scientists are most interested in studying, rather than the most threatened
species or those at risk of extinction. For instance, says Mark Burgman of the
University of Melbourne, lists compiled and used by organisations such as the
World Conservation Union (IUCN) and the Secretariat to the CITES agreement are
heavily biased toward birds, mammals and flowering plants, to the detriment of
less charismatic species such as insects and fungi. If no one tackles the
problem, Burgman believes we will unwittingly focus our conservation efforts in
the wrong places, and fail to stop the biggest mass extinction since the
dinosaurs.
Other conservation experts agree that some groups of plants and animals are
over-represented. But they insist endangered species lists are incredibly
valuable, despite their inherent bias. 鈥淎ll that it means is that we need a
great deal more information about other groups,鈥� says Edward O. Wilson of
Harvard University. The database of endangered species is continually growing in
size, reliability, and range of groups covered, he says.
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Burgman voices his concerns in next month鈥檚 Australian Journal of
Botany (vol 50, p 1), after the editors asked him to write a paper on the
threats to Australian land plants. He questions linking conservation policy and
legislation to lists of rare species. For instance, the CITES lists of
threatened and endangered species specify which animals and plants cannot
legally be traded between countries.
Another problem is that organisms cannot be included on endangered lists
unless scientists have researched them. 鈥淲e have an appalling and very
transparent bias鈥� that focuses on animals and plants that 鈥渆ither have utility
for us or are like us,鈥� Burgman told New Scientist. As a result, he
says, endangered lists, such as the IUCN鈥檚 Red List, are 鈥渃omposed almost
exclusively of vertebrates and flowering plants鈥�.
Scientific fads and whims can skew data by concentrating on certain groups
while ignoring others. Tasmania is thought to have 650 threatened species, for
instance. But 200 of these are hydrobiid snails. 鈥淚t鈥檚 not so much that there
are too many snails listed in Tasmania, as too few of everything else,鈥� says
Burgman. Collecting the snails was a popular fad in the late 19th century and a
few snail taxonomists have kept the tradition alive. While the snails are well
covered, less popular groups on the island don鈥檛 get a look-in.
Rare species lists also contain fewer threatened insects than birds, although
we know of nearly a million insect species and fewer than 10,000 birds. That鈥檚
because most insects are poorly studied, says Burgman. For most, all that we
have is a specimen in a museum and a brief formal description, he says.
Generally, little or nothing is known about their habitat and abundance, and no
one may have looked for them since their discovery. 鈥淲e assume all鈥檚 well
because we don鈥檛 have any evidence, and we don鈥檛 have evidence because we
haven鈥檛 looked,鈥� he says.
Like Wilson, Georgina Mace, director of science at the Zoological Society of
London and chair of the Species Survival Commission鈥檚 Red List Committee, thinks
Burgman has identified real problems. Yet she says that groups like the IUCN are
addressing them. Starting with amphibians, it has begun assessing the global
health of whole groups of related animals, species by species. Predicting the
risk of extinctions 鈥渋s an extraordinarily difficult thing to do,鈥� she told
New Scientist. Putting a species on the Red List is like assessing people
coming into a hospital emergency room, she says. It鈥檚 not a robust prediction of
what will happen, but it鈥檚 a quick way to pick out the sickest.
But Burgman says that the criteria for assessing whether a species will go
extinct varies from country to country and from study to study. He has compared
a range of studies and found that different methods produce very inconsistent
results. He says conservation scientists 鈥渘eed to get our act together鈥� and
develop a uniform set of tools that everyone can test and agree upon.
Even 鈥渆xtinction鈥� can be hard to define, he points out. A surprising number
of species have been declared extinct, only to resurface later after people had
given up looking for them. Most are small and inconspicuous, but one is the
half-metre tall ivory-billed woodpecker, the largest in North America. 鈥淲e鈥檙e
just making this stuff up as we go along,鈥� he says.