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Science
Tough guy in
a trendy
discipline
A man who is world-famous
for saving threatened
animal species has won the
CSIRO's highest honour.
David Mussared reports.
ONE NIGHT driving through the
rain in southern Queensland,
Graeme Caughley, an ecologist
with the Commonwealth Scientific and
Industrial Research Organisation in Can-
berra, saw a Tasmanian tiger. It was a
large dog-shaped animal with its tail
sticking straight out backwards and clear,
vertical stripes on its flanks.
Dr Caughley did a quick double-take.
Not only had Tasmanian tigers been ex-
tinct for 60-odd years, but they had not
lived on mainland Australia since long
before European settlement.
He swung the car around for another
look. What he found was a large, wet dog.
The stripes were water marks from the
rain.
The Tasmanian tiger, or thylacine, has
become a mythical creature in Australia
— akin to the Himalayan yeti. It became
extinct early this century, but every year
there are reported sightings of it in the
wild.
Dr Caughley himself spent holidays
searching the scrub in northern Tasmania
for some evidence — even just a paw
print — that the carnivorous marsupial
might still be alive. But he is grateful for
the sake of his scientific reputation that
the only thylacine he ever saw was in
Queensland.
"If I'd seen the same thing down in
Tasmania I'd probably have made a fool
of myself in the media," he says.
Most alleged sightings of modern-day
Tasmanian tigers, he says, happen on wet
nights when even a trained scientist can
easily be fooled. He now believes there is
no chance that the thylacine still lives.
That dog in the rain is a fitting meta-
Graeme Caughley: fooled on a wet night like many others. Help
Graeme Caughley: fooled on a wet
night like many others.
phor for the style of science which two
weeks ago won Dr Caughley the CSIRO's
highest honour — the annual $25,000
Chairman's Medal. The medal, instituted
by former CSIRO chairman Neville
Wran, is awarded each year to the best of
the best at the CSIRO, the scientist whose
work stands tallest in Australia and the
world.
Dr Caughley works in one of science's
trendiest disciplines with the Division of
Wildlife and Ecology at Gungahlin. But
his approach is that of a hard-headed,
old-fashioned scientist. He takes nothing
for granted.
By using advanced mathematics, and
by approaching old questions in new
ways, he has helped the world under-
stand, and stem, one of the most pressing
environmental issues — extinction.
Conservation biology has historically
been about looking at animals which have
been reduced to tiny populations, often in
zoos. The problem it has tried to solve is
how to rescue small numbers of animals
with severely limited genetic stocks.
That problem, Dr Caughley believes, is
really just a symptom. The real problem
is what reduced the animals to such a
fragile condition in the first place. By the
time only a handful of animals are left,
mostly in captivity, it may already be too
late.
Instead he looks at animals living in the
wild, ideally before they are on the brink
extinction, and tries to identify what
might be threatening them.
He cites the case of the Lord Howe
Island woodhen — a rescue operation
conducted by the NSW Government —
where the birds were reduced to a tiny
population living on top of a mountain. It
was widely assumed that the birds had
been driven to the edge of extinction by
feral black rats.
But rather than capture the birds and
try to breed them in a foreign zoo, the
researchers studied them on the island
and looked closely at what was threaten-
ing them. They found, in the end, that the
none Help
threat wasn't rats at all — it was feral pigs
introduced in the 1850s.
"The main approach that has been hap-
pening overseas is that they didn't even
ask what the problem was," Dr Caughley
says. "The problem was stated as: 'there
are too few animals'. We go in there and
find what has caused the problem, and
then we try to do something."
From musk oxen and caribou in Cana-
da to elephants in Africa; from kangaroos
in Australia to extinct giant birds in New
Zealand — Dr Caughley has left his mark
on the study of extinction pressures
around the world. He has also helped on
several continents to reverse those pres-
sures.
One colleague remarked last week that
it was a measure of Dr Caughley's global
stature that he had a beach named after
him in Victorialand in Antarctica.
He had eaten raw meat with Eskimos
on Victoria Island in the Arctic. "He's one
tough guy," was the awed description.
Dr Caughley is happy about the new
found fashionability of ecology among
budding young scientists. But he advises
would-be ecologists not to treat the disci-
pline as any kind of new-age occupation
— it needs good, hard science. Seeing a
dog in the rain is one thing; proving that
thylacines still walk the earth is another.
"My advice is they should get them-
selves a really solid grounding in scientif-
ic method — particularly mathematics,"
he says. "A lot of them end up in [ecology]
because they think its touchy-feely, but
they don't get very far. It calls for very
rigorous science. It doesn't work if you
just simply go in as a natural historian."
Dr Caughley's fresh approach to verte-
brate ecology has led to some unexpected
findings. By looking at statistics from the
African ivory trade in the 1950s and '60s
he showed that extinction pressure on
elephants was not a new phenomenon
suddenly beginning around 1980 as many
believed.
Before 1980 researchers were worried
that elephant numbers seemed to be
growing, not declining. But they were
studying the giant animals only in parks,
where they bred in relative safety. Out-
side park borders the ivory trade was
already taking its toll.
And in New Zealand Dr Caughley took
a new look at the way Maori immigrants,
and the rats they brought with them, sent
36 species of birds and insects extinct in
New Zealand when they first settled the
country about 1000 years ago — includ-
ing the giant moas.
By using existing carbon dates from
when the animals became extinct in dif-
ferent parts of New Zealand, Dr Caughley
was able to show that the Maoris took
anything up to 400 years to occupy all of
New Zealand; they did not settle all the
land almost immediately as was generally
believed. When Maoris moved into a new
area, it was about 100 years before all the
moas vanished.
Aside from the university textbooks he
has written for students of ecology around
the world, probably Dr Caughley's most
high-profile public role was the two years
he spent as a commissioner on the Aus-
tralian Government's Resource Assess-
ment Commission inquiry into forestry.
He is somewhat rueful about that expe-
rience in retrospect — "I'm not sure that
it achieved a hell of a lot" — adding one
more report on forestry to the pile of 40 or
so which went before it. But he is glad
nevertheless that he "had a bit of a go at
it".
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