But when it comes to conservation and animal rights, that faith may sometimes
be profoundly misplaced. Take the case of Patrick Bateson, an expert on animal
behaviour at Cambridge University. In 1997, he published a report suggesting
that hunting with hounds could lead to high levels of stress and muscle damage
in wild deer. The National Trust, which commissioned the report, immediately
banned deer-hunting on its land. The pro-hunting Countryside Alliance then
commissioned its own study, led by Roger Harris of the Royal Veterinary College
in Hertfordshire, which contradicted many of Bateson’s conclusions
(This Week, 19 September, p 5).

Bateson is now accusing both sides of misusing his science to promote their
own cause. He accuses the hunting lobby of “clutching at straws by grabbing the
most flimsy bits of evidence” to undermine his findings. But he also deplores
the way the anti-hunting lobby has interpreted his report to mean that
fox-hunting is cruel. “I have never said any such thing,” he says.

Some observers claim that the abuse of scientific findings by certain
pressure groups has become so entrenched that it threatens to undermine
conservation everywhere. “It’s a very serious problem,” says Chris Huxley, an
ecologist working for Cambridge-based Fauna and Flora International, which seeks
to protect endangered species. “Some groups have been caught peddling
misinformation so often that decision makers in the developing world are
beginning to question the validity of conservation arguments.”

Huxley cites the case of the African elephant, whose population was said by
conservation experts to have declined from 1.3 million to 650 000 during the
1980s. On the strength of these figures, which came from the Elephant Specialist
Group of the World Conservation Union (IUCN), the ivory trade was outlawed under
the Convention on International Trade in Endangered Species (CITES) in 1989.
However, before the ban, participants at a meeting in Botswana of the CITES
Ivory Trade Review Group heard from the IUCN scientists that the alleged decline
of 650 000 elephants included 300 000 in Zaire that had never existed.
Furthermore, it was admitted that figures for one area had been extrapolated for
the entire region.

“What astounded me,” says Huxley, “is that even though everyone accepted that
the figures had been fiddled, many scientists and environmental groups continued
to use them.” He accuses environmental groups of perpetuating the myth of a
catastrophic decline in elephant numbers across Africa. “Over 30 organisations
sprang up to save the elephant, and they and others have a vested interest in
exaggerating the crisis,” he says.

The ivory ban has since been partially lifted: Botswana, Namibia and Zimbabwe
will be allowed to start a limited trade with Japan next spring. But arguments
over the status of the elephant are still simmering. In 1989, Zimbabwe set up
the Communal Areas Management Programme for Indigenous Resources (Campfire),
which allows villagers to manage and profit from wildlife, including elephants,
outside national parks. Over 90 per cent of Campfire’s income comes from “trophy
hunting”, in which hunters pay to take away the tusks or heads of the animals
they kill.

The Humane Society of the United States (HSUS) claims that Campfire is
“biologically unsustainable” and that the elephant in Zimbabwe is “biologically
threatened”. However, a CITES panel of experts has found that between 1980 and
1995, Zimbabwe’s elephant population grew by 2.1 per cent—or an extra 1200
animals—a year, even with trophy hunting.

The ivory ban has deprived villagers in Zimbabwe of a much-needed source of
revenue, say conservationists there. More significantly, if the US government
did as the HSUS wished and stopped funding “sustainable use” programmes and
banned the import of hunting trophies, Campfire would suffer. “Not only would
that be a disaster for many communities,” says Jon Hutton, a zoologist with the
Africa Resources Trust, which is involved with Campfire. “It would also be a
disaster for conservation.” Most villagers will only tolerate crop-raiding
elephants if their communities benefit from Campfire payments.

None of this impresses the HSUS, however. Spokeswoman Teresa Telecky says the
organisation came to its conclusion that Campfire was bad for conservation after
looking at data from the US Agency for International Development, a major donor
to the programme. “Campfire is socially, environmentally and economically
unsustainable in its present form,” she maintains.

The “cherry-picking” of science has lain at the heart of the deer-hunting
debate in Britain. Last September Bateson and Harris, the two scientists who
found themselves on opposite sides of the fence, held a meeting to try to find
some consensus.

Shortly after this, Harris’s team claimed that the meeting had resulted in
“nine agreed points which essentially contradicted every conclusion of the
original [Bateson] report”. But Bateson claims this statement was “actively
misleading”. He admits that on certain matters he is now less confident, but
maintains that his central thesis—that hunting deer with hounds causes
suffering—has been generally accepted by the National Trust. “When the
evidence was unpalatable,” Bateson says, “the pro-hunting scientists have chosen
to ignore or misrepresent it.” Nigel Burke of the Countryside Alliance in turn
describes Bateson’s suggestions as “outrageous”.

The selective use of science has also been a feature of the whaling debate,
according to Philip Hammond, former chair of the International Whaling
Commission (IWC) Scientific Committee and director of the Sea Mammals Research
Unit at St Andrew’s University. When he was elected chair in 1991, the
committee’s most urgent task was to draw up a system of managing minke whale
stocks sustainably. In 1993, his committee unanimously recommended a new
mathematical model that determines whether whales could be safely caught.

But the IWC initially ignored the model. Clearly the commission, the majority
of whose members represent nations opposed to whaling, was not ready to accept
anything that might lead to its resumption. “It was a real slap in the face,”
says Hammond, who resigned in protest. Meanwhile, lobbying groups have tended to
emphasise those parts of the committee’s work that back their views. “It’s quite
clear that in the past the reports of the scientific committee have been
cherry-picked, and their findings taken out of context,” says Hammond.

The selective use of science seems most prominent where large mammals are
involved. Bateson believes that part of the problem stems from the public belief
that science should provide irrefutable answers to emotive issues. Pressure
groups frequently draw conclusions that go far beyond all the available
evidence.

Conservationists who promote programmes such as Campfire that “use” wildlife
have to be especially careful, says Hutton. “Ours is a very complex message and
if we’re to convince the public that conservation and culling can go hand in
hand, we have to be scrupulously honest.” Huxley believes that such programmes
have been generally honest in their use of science. But the reputation of
genuine conservationists, he says, has been sullied by groups who use science as
a commodity to fit their cause.

Recent estimates suggest that deforestation worldwide releases about 2
billion tonnes of carbon into the atmosphere every year through burning and
decomposition, a large proportion of which comes from the tropics. But according
to William Laurance at the National Institute for Research in the Amazon in
Manaus, Brazil, the figures do not take into account the extra carbon dioxide
produced by the fragments of forests left after clearing.

In an 18-year study of 66 forest fragments, published in Science
last November (vol 278, p 1117), Laurance and his team found that the fringes of
forests—within 100 metres of the edge—lose significantly more
vegetation than the inner areas because they are exposed to higher winds and
other extremes of climate. The resulting decomposition emits considerable
quantities of carbon dioxide and methane, two major greenhouse gases. The loss
of trees also means that there is less biological matter capable of absorbing
carbon dioxide from the atmosphere during growth.

Now, in a follow-up project, soon to be published in Forest Ecology and
Management, the researchers have calculated the amount of carbon dioxide
emitted by tropical forest fragments. They simulated three patterns of forest
clearing: the small-farmer settlement schemes of southern Amazonia, the large
cattle-ranching clearances typical of eastern Amazonia, and a random scenario
imitating unplanned forest loss. The first two account for most forest clearance
in the region.

In each case, the team tested various levels of clearance, from 5 to 95 per
cent of the land area. At every level, the random and the small-farmer scenarios
suffered the highest carbon losses— between two and five times more than
for the large cattle-ranching models—because they led to greater
fragmentation. The randomly cleared landscapes, in which irregular edges were
common, were especially prone to vegetation loss, even at very low levels of
clearance.

The team calculates that annual carbon emissions from fragmentation of
forests are between 3 and 15.6 million tonnes in the Brazilian Amazon and
between 22 and 149 million tonnes for all tropical forests at present rates of
clearance. This suggests that current estimates for carbon emissions from the
felling of tropical forests are up to 7 per cent too low, and as much as 42 per
cent too low in some areas, says Laurance.

“This prediction seems rather modest until one realises that this is the
equivalent of clearing and burning an additional 150 000 to 1 million hectares
of rainforest each year.” If anything, he says, the figures underestimate the
problem: the experimental plots were surrounded by regrowth forest which
provided some protection from wind. Fragments surrounded by cattle pasture and
crops would be fully exposed. Laurance says that governments should encourage
patterns of forest clearance that minimise fragmentation.

Julieta Benitez-Malvido of the National University of Mexico in Morelia
studied 11 fragments of forest ranging in size from 1 to 100 hectares near
Manaus, Brazil. She found that the density of shade-tolerant
seedlings—which represent the majority of trees—decreases
dramatically towards the forest edge, and is up to 40 per cent less in the
corners of a fragment than in the centre. She concludes that below a certain
size, rainforest segments cannot contain enough seedlings to fully regenerate
the plant species within them (Conservation Biology, vol 12, p
380).

“When I started the project, I thought seedling density would be higher
closer to forest edges, as the edges are lighter,” says Benitez-Malvido. In
fact, the opposite was true. One of the key factors was the change in climate
within the forest, with a hotter, drier environment near the edges preventing
germination of shade-tolerant species. They were also hindered by having to
compete with light-tolerant species that have higher growth rates.

The reduced number of animal species in small forest sections is also an
important factor. Around 80 per cent of tropical trees are pollinated by
animals, which also help to disperse the seeds and fruits. Fig trees, for
example, are pollinated by wasps and their seeds dispersed by bats, rodents,
monkeys, iguanas and ants. Fewer primates, birds and other animals means there
is less “seed rain”—seeds dispersed in faeces.

Benitez-Malvido concludes that even 100-hectare fragments do not nurture
enough seedlings to be self-sustaining. But she admits that preserving fragments
of 100 hectares or less may be the only option in some areas. “At least these
fragments can serve as germplasm pools for many animals and plants,” she says.
“We need to learn how to manage these patches to preserve them, and if possible
to increase their area.”

The IUCN Red List of Threatened Plants, published by the World Conservation
Union this week, includes 33 798 species, of which 380 are extinct in the wild,
371 may be extinct, 6522 are endangered and the remainder are vulnerable or
rare. “This is a huge number of species,” says Mark Collins, chief executive of
the World Conservation Monitoring Centre (WCMC), which compiled the study. “It’s
not just an aesthetic effect. This is an assault on the resources that people
depend on.”

The Red List is the culmination of 20 years’ work by scores of institutions,
led by the WCMC and the Royal Botanic Gardens (RBG) in Edinburgh and Kew. The
researchers analysed over 18 000 separate sources of data. Even so, the editors,
Harriet Gillett of the WCMC and Kerry Walter of RBG Edinburgh, believe there are
many threatened species that do not appear in the list: certain parts of the
world such as Brazil and central Africa are little known to botanists and are
under-represented.

Ninety-one per cent of the species listed are endemic to just one country.
Those growing on isolated islands are especially vulnerable, and are often
pushed out by plants and animals introduced by humans. Many threatened species
are economically significant. For example, a rare Chilean vine, Berberidopsis
corallina, is the basis of a basket-weaving industry, and a
species of Madagascan palm, Ravenea dransfieldii, is used for food. “In
any future conservation strategy, species that are economically important will
be clear candidates for priority treatment,” says Gillett.

The Red List makes no attempt to analyse why species are threatened, and
Gillett sees this as the next task. “It’s now crucial to know what the threats
are if we are to work out what action needs to be taken,” she says. Walter hopes
that the Red List “will wake people up to the fact that we spend very little on
conserving plants, yet there are many more threatened plants than threatened
animals”. He estimates that for every dollar spent on animal conservation, a
mere 10 cents goes towards plants.

Studies carried out in the 1980s estimated that pastures in the Arenal
watershed in Costa Rica were losing between 65 to 109 tonnes of soil per hectare
every year to erosion. Fearing that Lake Arenal would soon silt up, with major
implications for its hydroelectric dam, which generates over a third of the
country’s power, environmental groups and government agencies began to ask if
cattle ranching and dairy farming should not be restricted.

However, new research by the International Institute for Environment and
Development (IIED) in London and Costa Rica’s Tropical Science Centre in San
José and International Centre for Economic Policy at the National
University in Heredia shows that annual erosion from pastures averages 40 tonnes
per hectare, less than a quarter of which has an impact on generating capacity.
“This was our first surprise,” says Joshua Bishop, the IIED’s director of
environmental economics. “The second was that rather than posing a threat to the
watershed, farmers provide a significant benefit in the form of increased water
˛âľ±±đ±ô»ĺ.”

The researchers found that converting forest to pasture led to a net increase
in generating capacity. The increased run-off into rivers generated an extra 11
gigawatt-hours of electricity a year. This more than compensated for the 1.2
gigawatt-hours a year lost through sedimentation.

The small dairy farmers in the cloud forests in the upper reaches of the
watershed created the greatest increase in water yield. An intricate patchwork
of forest fragments and pasture—typical of poorer farming
communities—captures atmospheric moisture more efficiently than either
undisturbed forest or treeless pasture. A mix of trees and clearings increases
the surface area for condensation, thus adding to the rainfall.

Over a year, the researchers recorded precipitation rates of 3301 millimetres
for open ground, 2986 millimetres for primary forest and 3759 millimetres for
fragmented forest. “Forests do conserve water, but mainly for their own
purposes,” says Bruce Aylward, the study’s principal investigator.

The study points out that ranching makes economic sense if water is needed
downstream. Reforesting the pastures, as some conservationists have urged, would
put many farms out of business, and there would also be less water for power
generation.