Article from the New York Times:
Environmentalists
Hail the Ranchers: Howdy, Pardners!
September 10, 2002 By
JON CHRISTENSEN
ANIMAS, N.M. - Ever since the great cattle drives of
the Old West, ranching has been suspected of chewing up Western ecosystems. For
decades, environmentalists have tried to limit grazing from public lands, where
ranchers lease pastures from the government. But some scientists and conservationists
are now saying that cattle ranches may be the last best hope for preserving habitat
for many native species.
The
ranches could also be the best way to preserve grasslands and the periodic fires
that keep brush and cactuses from taking over.
In recent studies published
in peer-reviewed journals like BioScience, Conservation Biology, and Environmental
Science and Policy, scientists have concluded that large, intact working cattle
ranches are crucial puzzle pieces holding together an increasingly fragmented
landscape.
When ranches are subdivided into "ranchettes"
of 40 acres or less - a runaway trend - invasive species move in along with people
and their pets, and fewer native species can live on the land. And it becomes
much harder, if not impossible, to let fires burn across the land periodically,
a process that is now thought to be essential in many ecosystems.
The
studies emerge from a network of ecologists and ranchers, once at odds, but now
increasingly working together in the West.
"There is this lore
throughout the conservation community that ranching is bad, period," said
Dr. James H. Brown, a professor of biology at the University of New Mexico and
an expert on the ecology of the Southwest. "I think that is demonstrably
wrong. And a number of people are gathering data to demonstrate that."
Dr.
Brown noted, however, "It's clear some grazing practices have been enormously
detrimental." Studies have found damage from grazing in and around streams
in the desert West, for instance. But few studies have compared the alternatives
to ranching on the lands that are home not only to ranchers but to many animal
and plant species.
Dr. Richard L. Knight, a professor of wildlife biology
at Colorado State University, recently did just that, comparing 93 sites on ranches,
in wildlife refuges and in subdivisions with about one house per 40 acres.
He
found that the ranches had at least as many species of birds, carnivores and plants
as similar areas that are protected as wildlife refuges. Ranches also had fewer
invasive weeds.
More important, the ranches provided a better habitat
for wildlife than the ranchettes, which had fewer native species and more invasive
species than ranches and refuges.
Like many ecologists, Dr. Knight
had assumed that grazing hurt wildlife. "It finally dawned on me," he
said. "We made a mistake."
Demographic trends in the West
add a sense of urgency to the findings, Dr. Knight said. The population of the
West is growing rapidly and much growth is in rural areas.
As ranches
are carved up into subdivisions, the land consumption is growing at an even faster
rate than population, said Dr. David M. Theobald, a geographer at Colorado State
University. In the West, developed lands rose from almost 20 million acres in
1970 to 42 million in 2000.
Private ranch lands are often the most
productive lands in the West, too. Ranches are usually located at lower elevations
and have richer soils and more water than surrounding public lands.
Dr.
Andrew J. Hansen, an associate professor of ecology at Montana State University,
who studied ranch lands and ranchettes around Yellowstone National Park, found
that some songbirds from higher elevation public lands used the private ranch
lands as breeding grounds. But in the ranchettes, songbird death rates started
to exceed birth rates, because houses draw magpies and other birds that prey on
the songbirds.
Dr. Hansen speculated that the songbirds were getting
squeezed between increasing development at lower elevations and protected but
unproductive breeding grounds at higher elevations.
Grasslands, too,
are getting pinched in the midelevations, said Dr. Charles G. Curtin, a zoologist
and the director of the Arid Lands Project, a nonprofit research group. in Animas.
And it is not just by subdivisions. Climate and weather trends along with firefighters
have created good conditions for woody shrubs like dry thorny mesquite and have
conspired against grasslands.
Rather than being too disturbed by cattle
grazing, Dr. Curtin said, the grasslands in the boot heel of New Mexico, where
he does his research, have not been disturbed enough, mainly because of the absence
of periodic fires over the past century.
Dr. Curtin works with the
Malpai Borderlands Group in southern New Mexico and Arizona. The group is made
up of ranchers, scientists, conservationists and government land managers concerned
about preserving species and returning periodic fires to a million acres of mountainous
desert land, an area larger than Rhode Island and almost half the size of Yellowstone
National Park.
Malpai is derived from the Spanish word for badlands;
its craggy mountains, grassy plains and scrub-covered desert hills are home to
more than 20 threatened species. Like most of the West, the area is a checkerboard
of private, state and federal ownership. And it has subdivisions nibbling at its
flanks. It is also dotted with 200 monitoring sites, where scientists are studying
species of all kinds, including grasses and brush as well as rattlesnakes and
jaguars.
On the Gray Ranch, a 321,700-acre spread run by the nonprofit
Animas Foundation, Dr. Curtin has set up large test plots to study the effects
of grazing and burning on the grassland and the species that live here. Dr. Curtin
said that scientists, ranchers and conservationists here were trying to test "a
vast untested hypothesis: that grazing is a viable landscape process and ranching
is the most viable long-term method of protection."
Dr. Curtin
said scientists had generally concluded that only some ecosystems could support
long-term grazing. It seems to depend on rainfall and whether herbivores were
present for thousands of years and thus were part of the system, as bison were
here, he said.
In collaborations with other groups, Dr. Curtin hopes
to conduct the same experiments on 20 ranches around the West, and in Africa as
well. So far, Dr. Curtin said, his research indicates that grazing here does not
have much of an effect on grasslands and shrubs.
Fire is more important
in knocking down shrubs and encouraging grasses. But climate and weather are the
major forces.
Dr. Brown, who has monitored the changing vegetation
on experimental plots in nearby Portal, Ariz., for 24 years, agreed. An increase
in winter precipitation driven by El Niño events has favored woody shrubs
over grasses, he said. But with climate and weather being out of human control,
"the only things you can really manage are fire and grazing," added
Dr. Brown, a science adviser to the Malpai group.
The group is also
experimenting with fire on a grand scale. Ranchers and federal land managers are
working with scientists on a species habitat conservation plan that will set the
stage for coordinated planning over the entire region, rather than for one endangered
species at a time. One result is a "fire map" that shows where wildfires
will be allowed to burn on private property with the landowner's consent.
In
the Malpai area, wildfires can burn freely now on most of the land, up to the
northern border, where real estate signs on newly divided land signal the end
of any chance to keep natural forces at work.
"What you see is
the result of 90 years of fire suppression," said Larry Allen, a retired
Forest Service official who has worked with the Malpai group to plan prescribed
burns. He pointed out an area that had not burned in many years and was thick
with mesquite.
"If you do nothing, the mesquite will take over,"
Mr. Allen said. He then pointed to an area where a prescribed fire burned 12,000
acres in 1997 and grasses now grow thickly between widely spaced mesquite. "But
you put a little fire in it," he said, "and it'll do miracles."
Bill McDonald, a rancher who is executive director of the Malpai group,
said the two prescribed burns the group had managed to set since 1995 had helped
restore grasslands.
"We just need another one," he said.
"But the fire program has been set back by what happened in Los Alamos,"
he said, referring to the planned fire that got out control and burned homes two
years ago. "They're so skittish."
Mr. McDonald said that
scientists working in the area confirmed much of what local ranchers had long
suspected about grazing and fire, except for one thing. "I'm surprised cattle
grazing isn't a bigger impact for better or worse," Mr. McDonald said. "I
guess it's not the biggest thing you see out there that is having the biggest
impact."