Scientists Anticipate Sixth Great Extinction
Environmental News Network
By Ed Stoddard
KRUGER NATIONAL PARK, South
Africa (Reuters) - Seemingly oblivious to the large group
of crocodiles resting on a nearby sandbank, four rare
black storks sun themselves in South Africa's Kruger National
But the real danger to these
elusive birds, which resemble colorful sentinels with
their striking red beaks and legs set against glossy black
feathers, is not the razor-sharp teeth of the crocodiles
who lie just a few yards away.
It is the teeth of chainsaws
thousands of miles to the north, where old growth forests
-- habitat vital to the bird's survival -- are being mowed
The black stork is one of
many species which scientists fear could follow the dinosaurs
down the road to extinction because of human activities
such as logging, farming and building dams.
Many credible scientists fear
that the sixth mass extinction in the planet's long history
is unfolding -- a doomsday scenario dismissed as alarmist
A recent U.N. report, prepared
ahead of a summit next month in Johannesburg on the environment
and poverty, warned that 12 percent, or 1,183 bird species,
and 1,130, or nearly a quarter of all mammal species,
are regarded as globally threatened.
A SIXTH EXTINCTION?
Mass extinctions have occurred
five times in the four billion year history of life.
They are loosely defined as
moments in geological history when half or more of all
marine species -- which today are preserved in fossils
-- die off in a short period of time. (Terrestrial life
is also not believed to fare well during these periods).
According to one book on the
subject, "The Sixth Extinction," by Richard Leakey and
Roger Lewin, the grim reaper first visited Earth on this
vast scale 450 million years ago.
The second mass extinction
took place 100 million years later, giving rise to coal
forests. In the Triassic period 250 and 200 million years
ago, two mass extinctions snuffed out countless species.
Then, 65 million years ago,
scientists believe the dinosaurs were killed off when
a giant meteorite collided with Earth.
Scientists say the sixth extinction
will have been brought about entirely by people.
"In the next 50 to 100 years
there is a good possibility that there could be a mass
extinction of species which is human-induced," said Dr.
Susan Lieberman, director of the Species Program for the
World Wide Fund for Nature (WWF).
"We are heading for a crisis.
And we have to act now if we are going to avert this,"
she told Reuters.
Leakey and Lewin estimate
that perhaps 50 percent of all species will become extinct
in the next 100 years. Others take a more measured view
but agree that a crisis is looming.
Bjorn Lomborg argues in his
controversial recent book, "The Skeptical Environmentalist,"
that we could lose about 0.7 percent of the planet's species
over the next five decades -- an estimate far below many
but one which he says is "not trivial."
Most scientists concede that
the number of recorded extinctions to date is far less
than the "so many lost each day" estimates cited in the
more alarmist literature.
The Committee on Recently
Extinct Organisms says at least 70 species of fish, birds
and mammals have disappeared since 1970.
The WWF says 81 freshwater
species of fish are recorded to have become extinct in
the last 100 years. The majority, 50, were endemic to
Africa's Lake Victoria and vanished because of the introduction
there of the voracious Nile perch.
Biologists say that countless
species which have never been discovered -- notably in
tropical rain forests and marine ecosystems -- have probably
become extinct already.
BLACK STORKS AND WILD DOGS
The black stork and wild dog,
two species in Kruger which nobody disputes are endangered,
sum up the threats to many.
The black stork's global population
is about 7,000 to 9,500 nesting pairs, according to Latvian
ornithologist Maris Strazds.
The biggest population, about
4,500 to 6,000, is found in Europe, mostly in Poland,
Belarus and Latvia.
Unlike their more gregarious
and numerous cousin the white stork, which often nests
on farmhouses in Eastern Europe, the shy and reclusive
black stork prefers to decamp far from the madding crowd
in the quiet of old growth forests which are being targeted
"Latvian black storks nest
in pine trees which are on average around 200 years old.
And trees of that age are very much in the sights of loggers,"
said Strazds, whose name is Latvian for thrush.
Strazds said laws mandate
a 50 acres logging ban around their nests, but land owners
often simply cut their trees down and plead ignorance
to the presence of the birds.
"The Latvian black stork population
is bound to fall to some 500 pairs (from about 900 pairs)
because of logging...but if we do not observe nest protection
rules, it could fall rapidly to 20-odd pairs in two decades
or so," he said.
Habitat destruction by people
is probably the primary cause of species decline.
The U.N.'s Food and Agriculture
Organization estimates that forests, which cover around
a third of the world's land surface, have diminished by
2.4 percent since 1990.
The biggest losses have been
in Africa, where 130 million acres or 0.7 percent of its
forest cover has vanished in the past decade. Luckily
for Kruger's black storks, their home habitat is at least
Another Kruger resident, the
wild dog, highlights the age-old persecution of predators
Also known as the "painted
wolf" because of the splashes of vivid color across its
coat, the wild dog is the second rarest carnivore in Africa
after the Ethiopian wolf.
A highly social animal that
hunts in packs, its numbers have been reduced to an estimated
5,000 -- mostly in parts of southern Africa and Tanzania
-- mainly because of shooting and poisoning by farmers
worried about their livestock.
But even in a conservation
stronghold such as Kruger, its numbers are dwindling.
"The number of wild dogs here
is down to under 200 now from over 400 a few years ago,
and we really don't know why," said Kruger zoologist Gus
This is a cause for concern
because, given their reputation with farmers and their
small numbers, it seems doubtful they could survive for
long outside protected or very remote areas.
There are other threats to
species besides habitat loss and persecution, including
global warming and pollution.
Humanity's soaring population,
especially in developing countries, is seen as putting
added pressure on land and scarce resources, to the detriment
of the other species we share the planet with.
The WWF's most recent Living
Planet Index (LPI), based on population trends of hundreds
of species of birds, mammals, reptiles, amphibians and
fish, has fallen 37 percent over the past 30 years.
"...Current human consumptive
pressure is unsustainable," it says.
Humanity's impact on biodiversity
will be high on the agenda at the World Summit on Sustainable
Development, known as Earth Summit 2, which will be held
in Johannesburg from August 26-September 4.
Conservationists hope historians
do not look back five decades from now and see it as a
missed opportunity to avert what could be the greatest
loss of life on the planet since the death of the dinosaurs.
(Additional reporting by Martins Gravitis in Riga)