| Dear
EarthTalk: Is it true that biologists want
to bring African and Asian wildlife to roam free in North
America to help restore natural ecological balances here?
If so, what are the implications for biodiversity and our
environment?
-- Naturegirl, Victorville, CA
A
group of biologists and environmentalists is advocating
just such a plan to help save wild animals from extinction
and restore the ecological vitality of North America’s
wildlands to a state that existed before humans set foot
on the continent some 13,000 years ago. The concept—whereby
large mammals are reintroduced across the continent to fill
ecological gaps abandoned eons ago—was first posited
publicly two decades ago by bio-geographer Paul Martin of
the University of Arizona.
In
arguing for the introduction of lions, elephants, camels
and other large mammals from around the world to North America,
Martin cites the important role that so-called “megafauna”
play in maintaining overall ecosystem integrity, including
keeping predator/prey populations in balance and invasive
species in check. Some conservationists like the idea because
hosting such large mammals would require a large amount
of preserved, natural open space for habitat. Others see
it as a terrible idea, citing human safety issues and the
difficulty such exotic animals might have adapting to such
different landscapes and ecosystems.
Building
on Martin’s ideas, a group of conservationists came
together in 2004 to form the New Mexico-based Rewilding
Institute. Members of the group co-authored a 2005 commentary
in the scientific journal Nature, in which they suggested
starting with a series of controlled experiments on fenced
private land, as was previously done with condors and bison
and led to population rebounds. Some of the first species
suggested for North American introduction include giant
tortoises, wild horses, camels and elephants. If such experiments
pan out, cheetahs and lions could be next.
The
group also wants to restore native species such as mountain
lions and wolves, both of which roamed North America in
large numbers before European settlers first arrived in
the 1600s. The group argues that the U.S. Fish and Wildlife
Service has approached recovery of these animals “in
a haphazard and minimalist way.”
“Obviously,
gaining public acceptance is going to be a huge issue, especially
when you talk about reintroducing predators,” says
Josh Donlan, Cornell biologist and lead author on the Nature
article. “There are going to have to be some major
attitude shifts [including] realizing predation is a natural
role, and that people are going to have to take precautions.”
Donlan
adds that “rewilding” could be a win-win situation
as far as people and wildlife are concerned. Portions of
the Great Plains, for instance, could see an increase in
tourism dollars as people flock there to see the wildlife,
while the animals themselves—many of which are seriously
endangered in their native lands—can take advantage
of increased habitat and a decreased threat of extinction.
CONTACTS:
The
Rewilding Institute.
Dear
EarthTalk: Is removing the salt from ocean
water (desalination) a feasible fix for the world’s
shortage of fresh water?
-- Nora Jones, Sydney, New South Wales, Australia
Fresh water scarcity
is already posing major problems for more than a billion
people around the world, mostly in arid developing countries.
The World Health Organization predicts that by mid-century,
four billion of us—nearly two-thirds of the world’s
present population—will face severe fresh water shortages.
With human population
expected to balloon another 50 percent by 2050, resource
managers are increasingly looking to alternative scenarios
for quenching the world’s growing thirst. Desalination—a
process whereby highly pressurized ocean water is pushed
through tiny membrane filters and distilled into drinking
water—is being held forth by some as one of the most
promising solutions to the problem. But critics point out
it doesn’t come without its economic and environmental
costs.
According to
the non-profit Food & Water Watch, desalinated ocean
water is the most expensive form of fresh water out there,
given the infrastructure costs of collecting, distilling
and distributing it. The group reports that, in the U.S.,
desalinated water costs at least five times as much to harvest
as other sources of fresh water. Similar high costs are
a big hurdle to desalination efforts in poor countries as
well, where limited funds are already stretched too thin.
On the environmental
front, widespread desalination could take a heavy toll on
ocean biodiversity. “Ocean water is filled with living
creatures, and most of them are lost in the process of desalination,”
says Sylvia Earle, one of the world’s foremost marine
biologists and a National Geographic Explorer-in-Residence.
“Most are microbial, but intake pipes to desalination
plants also take up the larvae of a cross section of life
in the sea, as well as some fairly large organisms…part
of the hidden cost of doing business,” she says.
Earle also points
out that the very salty residue left over from desalination
must be disposed of properly, not just dumped back into
the sea. Food & Water Watch concurs, warning that coastal
areas already battered by urban and agricultural run-off
can ill afford to absorb tons of concentrated saltwater
sludge.
Food & Water
Watch advocates instead for better fresh water management
practices. “Ocean desalination hides the growing water
supply problem instead of focusing on water management and
lowering water usage,” the group reports, citing a
recent study which found that California can meet its water
needs for the next 30 years by implementing cost-effective
urban water conservation. Desalination is “an expensive,
speculative supply option that will drain resources away
from more practical solutions,” the group says.
Despite such
arguments, the practice is becoming more common. Ted Levin
of the Natural Resources Defense Council says that more
than 12,000 desalination plants already supply fresh water
in 120 nations, mostly in the Middle East and Caribbean.
And analysts expect the worldwide market for desalinated
water to grow significantly over the coming decades. Environmental
advocates may just have to settle for pushing to “green”
the practice as much as possible in lieu of eliminating
it altogether.
CONTACTS:
Food
& Water Watch; NRDC,
Turning Oceans into Tapwater. |
