In a human-dominated planet, it is only natural that
wilderness and wildlife will be increasingly disrupted,
hemmed in or exterminated.
That has been happening steadily through the era of
industrialization, which created today's wealthy minority,
and will happen far more, biologists say, as the developing
world strives to become developed.
In the face of this trend, conservationists and scientists
have tried a host of strategies to preserve the world's
shrinking mosaic of untrammeled ecosystems: establishing
parks; pushing for laws protecting endangered species;
publicizing "biodiversity hot spots," places where wilderness
and people dangerously overlap.
But on almost every front, they find themselves falling
back, like an army under surprise attack from within and
without. Nothing is simple any more, many scientists lament.
Even the definition of "wild" is open to debate.
With some species fading and others in transit, the
experts have to decide simultaneously which wildlife to
protect and which to get rid of.
Accelerating trade and migration have resulted in large-scale
invasions of islands and continents by new species and
the disruptions of longstanding ecological regimes that
many naturalists have long treasured. An entire field,
restoration ecology, has arisen to defend "native" species
against "alien" invaders.
Hawaii's birds exemplify the problem, falling to extinction
one by one, besieged by pigs, rats, cats and other imports.
On the East Coast, marshes of native cordgrass have
become overgrown with an exotic species, the common reed.
Restoration ecologists had once hoped to return these
marshes to a self-sustaining population of cordgrass,
but have instead been fighting a continuous and, some
say, losing battle against the hardy reed.
`'You have to keep herbiciding," said Dr. Joy B. Zedler,
a restoration ecologist at the University of Wisconsin.
"You have to keep spraying it year after year, and the
minute you stop it'll come back in."
So a growing chorus of biologists is proposing a new
approach to the fast-blending biosphere. They say change
should be accepted as largely inevitable and choices for
managing nature should be based on what is desirable and
undesirable, not what is native and foreign.
Altogether, researchers estimate that 50,000 species
have invaded the United States as a result of human activities.
North America, as a result, has 20 percent more plant
species now than it did before colonization, biologists
say.
"They're not going back," said Dr. Mark A. Davis, an
ecologist at Macalester College in St. Paul who has been
exhorting colleagues to stop viewing nonnatives as necessarily
bad since, he says, most are harmless.
He suggests accepting these species as the new immigrants
— a biological reflection of the same globalization affecting
economies, societies and information.
"It's never-ending to try to keep a habitat pure," he
said, "You're fighting natural processes at some point."
But many of his fellow ecologists are appalled.
"If we ignore this, it gets us gypsy moths and chestnut
blight and any number of other ecological disasters that
greatly reduce our flexibility for future options and
reduce the beauty of the natural world," said Dr. Guy
McPherson, an ecologist at the University of Arizona,
echoing others.
Some 400 of the 1,000 or so species that are listed
as endangered are thought to be at risk, primarily because
of competition or predation from nonnative species, Dr.
McPherson added.
While that is indeed thought to be the case, Dr. Davis
said, few rigorous studies document such effects.
Dr. Davis said the real villain driving extinction rates
around the world was loss of habitat. Instead of focusing
on native or alien, Dr. Davis said, humans should start
becoming comfortable with controlling the textures of
ecosystems based on what works — ecologically, aesthetically,
or otherwise -- and what does not.
He noted that nest-robbing brown-headed cowbirds are
native to North America, as are hantavirus and Lyme disease.
"Native versus exotic doesn't make ecological sense,"
he said. "It doesn't make practical sense, and it drives
a lot of attention and energy away from really important
problems we should be addressing."
The most pressing question for many conservationists
is what species or habitat to save.
Often, they rely on sheer numbers to make the tough
decisions.
Following the simple rule that more is better, conservationists
are giving highest priority to biodiversity hot spots
— those places that are rich in species and often lush
and beautiful. The strategy was refined by Conservation
International, an influential private group in Washington.
But now some scientists have begun to challenge even
this once unassailable formula. `'Biodiversity hot spots
are just places with a lot of unique plant species," said
Dr. Peter Kareiva, a lead scientist at the Nature Conservancy.
He has been urging conservationists to look beyond simple
species counts when deciding how to dispense limited resources.
"You have to be mindful of uniqueness," Dr. Kareiva
said. "Look at biodiversity cold spots and you'll find
they're pretty valuable to people, like the Serengeti
or all of Alaska."
After important habitat is identified, another problem
confronts battle-weary scientists and officials seeking
to hold back bulldozers, chain saws and fishing nets.
Instead of just establishing parks, building fences
and hiring guards, some conservationists are moving to
something akin to conservation judo, they say, using the
power of their opponents to their own advantage.
Last year, for example, surveys by the World Conservation
Union and Future Harvest, a group promoting traditional
agriculture, found that half the world's 17,000 major
wildlife refuges were being heavily used for agriculture.
In fact, the survey found, some reserves actually attract
impoverished settlers seeking land.
These findings have convinced some conservation biologists
that they should work with farmers to preserve some habitat
and find ways to prevent wildlife from consuming crops.
"To avert widespread extinctions and feed the world,
we must integrate biodiversity preservation into all landscapes
— from grazing lands to coffee plantations to rice paddies,"
said Jeffrey A. McNeely, the chief scientist at the World
Conservation Union.
This integration can be as simple as establishing windbreaks
of trees between dairy pastures, as has been done in Costa
Rica. The rows of trees serve as corridors for the passage
of wildlife.
In the seas, similar efforts are under way. Fishermen
in St. Lucia in the Caribbean initially opposed the establishment
of protected marine reserves along some coasts but now
support the project because catches in adjacent fishable
waters have risen 30 percent or more.
Meanwhile, though, scientists seeking to preserve wild
things on an increasingly modified earth struggle to define
their goals, when native wildlife increasingly mixes with
introduced, farmed or hybridized varieties.
Many of the Florida panthers that prowl in state refuges
are no longer pure but instead a result of crossbreeding
with Western mountain lions.
Ranching groups in the West have petitioned the Fish
and Wildlife Service to remove gray wolves from the federal
list of endangered species because many may actually be
mixed breeds of wolves and coyotes. The red wolf in the
Southwest has come under similar scrutiny.
In the Pacific Northwest, fights have sprung up around
salmon species that are protected by states and the federal
government, while those same species are being bred in
fish hatcheries.
The protections come with real costs, with farmers denied
water and loggers denied access to forests. The new debate
has repeatedly landed wildlife scientists in court, defending
or attacking decisions about what is rare, what is special,
what should be saved.
Which leads to yet another question: who decides what
is special? If left to a majority, weaned on the Discovery
Channel and National Geographic, the wild world of the
future may end up looking cuddly and cute — still populated
with pandas and other so-called charismatic megafauna
— but may not have much biological integrity deep down.
Ecologists say that ecosystems are often built on the
backs of creatures that can only be called uncharismatic
microfauna.
In many ways, some conservation biologists say, this
spate of new challenges is just the next step in the maturing
of this still relatively young field. In what some are
referring to as the conceptual adolescence of conservation,
researchers are beginning to get away from simplistic
notions of a return to an untampered wilderness and instead
starting the harder journey toward a future of human choices,
intervention and management.
"Conservation biologists are too romantic," Dr. Kareiva
said. "They think what's good is what's natural. Let's
be serious. A better vision is something that functions
and has habitat quality and aesthetic quality. We have
to ask, What do we want the natural world to look like
100 years from now?"
