The ironic thing I noticed on the 7.30 report segment was the amount of
footage given to rainbow lorikeets and sulphur-crested cockatoos.
Anyhow, I came across an interesting item on extinction in the New York
Times [it kind of reminds me of the "I'm not dead yet" line from Monty
Python]
___________________________________________________________________________
http://www.nytimes.com/2000/10/24/science/24EXTI.html
October 24, 2000
Extinction Turns Out to Be a Slow, Slow Process
By ANDREW C. REVKIN
Scientists studying the planet's stressed-out rain forests, rivers,
reefs,
deserts and islands are increasingly confronting a new kind of species ?
the
living dead. They are extant, but, in almost every way, are already
extinct.
There is the Javan rhinoceros, reduced to 70 or so animals split
between a tiny
tract in Indonesia and another in Vietnam. There is the golden Vizcacha
rat,
which was recently discovered along one edge of a remote salt flat in
northwest
Argentina, just in time for its discoverers to see its tiny habitat
being
replaced by irrigated olive orchards.
Then there is the Hawaiian po'ouli. The number of these black-masked
honeycreepers on the mountains of Maui has dropped from about 200 in the
1970's
to just 3 today. Each inhabits a separate bit of mountainside, unaware
it is not
alone. Scientists do not know the sex of the birds.
Such species, to borrow a bleak phrase from emergency-room doctors, are
circling the drain. But they have been able to persist far longer than
the
experts studying them ever anticipated.
It turns out that many species on their last legs ? or wings or bellies
or
roots ? somehow find ways to adapt, albeit temporarily, to stark changes
in
their surroundings. Lonely hearts occasionally find each other to bear a
few
more offspring and so keep a unique genetic branch on the tree of life
growing
just a little bit longer.
They have come to symbolize the challenges faced by biologists who are
studying
and trying to save endangered species. Extinction has proved to be
complex and
sometimes excruciatingly slow, often tantalizing conservationists with
the
prospect of bringing a fading species back.
Some, like the Puerto Rican parrot, which has rebounded after seeing
its
population fall to just 12 birds, do seem capable of recovering. But
others do
not, even when they stare a biologist in the face.
Dr. Stuart L. Pimm, an extinction expert at Columbia University,
pointed to the
example of the po'ouli, whose last known members were tracked down
several years
ago by two of his postdoctoral students after three years of slogging
through
sodden forests.
"There is an extraordinary sense of loss when you see wonderful animals
and
plants and you know you may be the last people to see them," Dr. Pimm
said. "The
po'ouli lingered below 10 or 20 individuals for years. It's rather like
looking
at some old, beloved relative who you know is simply not going to last
another
year or two. You don't know exactly when old uncle Joe is going to die."
In fact, the dogged quality of life in its end stages has come as a
slight
embarrassment to more than a few ecologists and conservation biologists.
Two
decades ago, in studies like the Carter administration's Global 2000
Report,
many experts were predicting that some 20 percent of the world's species
at that
time would be erased by now ? largely because of the accelerating,
intensifying
impact of humans on the landscape.
That may well be happening, but no one has proved it. In fact, often as
not ?
at least for conspicuous creatures like birds and mammals ? an isolated
few
specimens tend to pop up just when scientists have decided they cannot
possibly
still exist.
There is a growing realization among ecologists that the endgame for
species is
not nearly as straightforward as it is portrayed in mathematical models.
These
predict extinction rates by crunching the density of species in a
habitat, the
size of the habitat and the rate at which it is destroyed. The
discrepancy
between theory and reality has led some biologists to call for a change
in the
way conservationists describe the extinction process to the public, and
in the
way that scientists study it.
A growing group of paleontologists and ecologists are calling for a new
push to
improve the data behind estimates and to stop making broad statements
comparing
current events to past cataclysmic extinction spasms like the one that
erased
the dinosaurs 65 million years ago. Those comparisons, they say, implied
a level
of clarity in the science that just does not exist. They add that
scientists
should emphasize that extinction itself happens over a span that is
always going
to be hard to measure or comprehend.
"In thinking about global extinction we've got to free ourselves from
this
human time scale," said Dr. John Alroy, an ecologist at the National
Center for
Ecological Analysis and Synthesis of the University of California at
Santa
Barbara. "To a species, a human lifetime is a little flicker."
Human-caused extinctions are happening, Dr. Alroy said, and he is one
of many
biologists who are convinced that the pace is rapidly accelerating. It
is just
that this wave of biological losses is building but has yet to break.
Only in retrospect, when some future culture ? human or otherwise ?
examines
the fossil record, will the die-off be evident as a substantial pruning
of the
branches of the tree of life, he said. "For the entire remaining
duration of
life on earth," he said, "this event we're responsible for is clearly
going to
show up as a signature."
Instead of focusing on the nearly immeasurable moment when a species
ceases to
exist, he and other biologists say, science should focus harder on the
forces
that lead toward extinction ? the destruction or fragmentation of
habitat, the
introduction of invasive species, the appropriation of water or other
vital
resources.
Dr. Alroy is one of dozens of scientists who are essentially trying to
forge a
new discipline, extinction biology, incorporating ideas from field
studies,
genetics, ecology and paleontology.
They are seeking to know ? up close and in current time ? a process
that
formerly was almost exclusively studied by paleontologists digging
through dusty
layers of fossils. Mostly, they are trying to develop an agenda to
improve the
scientific underpinnings that could clarify why some species last and
others do
not.
Part of the difficulty in extending extinction science from the past
into the
present lies in figuring out how to reconcile the clues left by past
comings and
goings of species with those providing hints of what may be happening to
existing species.
The main tool used by biologists to calculate current extinction rates
is a
longstanding formula called the species-area curve, which gives an
estimate of
species lost for a given area of habitat destroyed. Another is
population
viability analysis, which uses computer models to project trends in a
range of
conditions affecting isolated populations of a species and calculates
the
probability of long-time survival.
"Conservation biologists see changes in the environment and estimate
the impact
on species, while paleontologists see a record of change in species and
try to
match what environmental issues drove those changes," said Dr. David
Jablonski,
a paleontologist at the University of Chicago. "The fundamental problem
in all
this is the ways we estimate extinction intensities are totally
different."
Many conservation biologists and groups have compared the current
extinction
episode with the five great dyings that punctuate the fossil record, but
Dr.
Jablonski and many paleontologists say the data are so different ? and
so
incomplete in both realms ? that there is no way to relate past
extinctions to
whatever is happening now.
Much more needs to be done to mesh the two disciplines, he said,
adding,
"Often, I'm the token paleontologist at conservation biology meetings."
That has
to change, he said.
A central challenge frustrating scientists studying the most imperiled
species
is that they are just nibbling at the edges of the world's biological
diversity,
a fact borne out in the vast gap between the number of species
classified by
science ? fewer than 2 million ? and the latest far-flung estimates of
what is
out there: anywhere from 7 million to more than 100 million, depending
on who is
counting.
The complexity of extinction, and the vastness of the biosphere, have
prompted
many scientists to call for a large increase in the number of biologists
working
both in the field and in museums or laboratories to clarify the
relationships
and characteristics of the planet's myriad endangered life forms.
Dr. Edward O. Wilson, an entomologist and ecologist at Harvard
University who
helped invent the current methods of estimating extinction rates,
published an
essay in Science last month calling for a large effort to improve
mapping of
biodiversity around the world.
"Right now we spend between $150 million and $200 million a year in the
United
States on studying global fauna and flora," Dr. Wilson said. "That's
just
dabbling. Compared to the magnitude of the problem, it's chump change."
He and other biologists acknowledge that the need comes just as the
explosion
of advances in genetics and molecular biology is attracting some of
biology's
brightest young minds ? and a lot of the available grants and government
money.
"If you say I want to go out and look for new mammals that have never
been
found, it's hard to get support," said Dr. Michael A. Mares, a
mammalogist and
director of the Sam Noble Oklahoma Natural History Museum at the
University of
Oklahoma. It was Dr. Mares whose team recently discovered the golden
Vizcacha
rat living on the edge of salt flats.
The nocturnal rodent eats a desert plant that is four times as salty as
sea
water. Dr. Mares discovered it while working far from the "biodiversity
hot
spots" that have become a prime focus of conservationists lately. Even
in remote
Argentinian deserts, pressure from agriculture is intruding, he said.
While areas with the most species and the most threats are clearly
vital to
protect, he said, someone has to keep looking on the fringes.
"In this very isolated valley, you've got the possibility of three or
four
species and one genus disappearing with very little habitat damage," he
said.
"These are not charismatic species," he added. "But they play an
important role
in the ecosystem and do some very interesting things."
Other biologists stress the importance, at the same time, of improving
understanding of what is happening close to home, in places like the
woods
tucked amid American suburbs. Extinction and endangerment are not
limited to
faraway tropics, said Dr. David B. Wake, a biologist at the University
of
California, Berkeley, who divides his time between the cloud forests of
Costa
Rica, the suburbs of Southern California and the stream-laced mountains
of the
Pacific Northwest.
Dr. Wake, whose work in Costa Rica 15 years ago first hinted that a
substantial
die-off of frogs and other amphibians was taking place, said that
salamanders
tucked in moist pockets of woodlands in Southern California contained
enormous
genetic diversity.
Now, though, isolated populations are being quietly rooted out with
each
advance of roads and subdivisions, he said. "I've watched this happen,"
he said.
"I've seen these tiny spots going out. A cougar or bird couldn't exist
there,
but salamanders can. The challenge for the future is not that we're
losing all
these species in the rain forest; we're losing them in our backyards."
Finally, some scientists say, for extinction biology to gain more
credibility,
more work is needed to improve the basic taxonomic data determining just
what is
a species. Last year, Dr. Ross D. E. MacPhee, the curator of mammals at
the
American Museum of Natural History, published an analysis of the mammal
extinctions in the 1996 Red List, a quadrennial roster of the planet's
intensive
care ward published by the World Conservation Union, and found dozens of
instances in which species on the list either were not extinct or were
misidentified ? and also of extinct species that the list had missed. A
separate
analysis of data for fish extinctions produced similar findings.
Some biologists stress that concern over the current turmoil in the
natural
world should be tempered with the awareness that change, sometimes a lot
of it ?
including extinctions and new bursts of speciation ? is an essential
part of the
ferment of life on earth.
And life can prove quite tough and adaptable. Puerto Rico, which lost
97
percent of its forests in the centuries following European settlement,
is almost
completely forested again, local scientists say, with a mix of exotic
and native
species. And sometimes species, with a little help, do pull back from
the brink.
The ginkgo tree was nearly extinct in its home range of China, preserved
only on
the grounds of a few monasteries. Now it has spread around the world and
is
ensconced in some rather unforgiving ecosystems, including Brooklyn.
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