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  • From: "Tradingpost" <tradingpost@lobo.net>
  • To: livingontheland@lists.ibiblio.org
  • Subject: [Livingontheland] Prof: Grazing a mixed bag
  • Date: Thu, 16 Jul 2009 14:34:25 -0600




Prof: Grazing a mixed bag
http://www.azdailysun.com/articles/2009/07/15/news/20090715_front_199915.txt



By CYNDY COLE
Sun Staff Reporter
Wednesday, July 15, 2009

There's a lasting and fiery debate between some conservation-minded people
and beef ranchers and eaters: Do cows harm the land?

The parties in this argument have become polarized, to the point of dueling
research stating vegetation absolutely can or absolutely cannot thrive
without cattle, said Tom Sisk, a professor and conservation biologist at
Northern Arizona University. So Sisk and colleagues set out a little more
than a decade ago to shed some light on the question, and what they found
was a little surprising to them.

Starting in 1997, Sisk and researchers Matthew Loeser and Timothy Crews
began sectioning off small parts of the 90,000-acre Flying M Ranch on
Anderson Mesa east of Flagstaff.

Some parts got intensely heavy grazing, chewing down most of whatever was
there.

Some got none.

And most of the land received moderate grazing, with about 850 head of
cattle currently. All of them were removed temporarily when the ranch ran
out of water in 2002.

The ranch has Angus, among others, and it breeds cattle for sale elsewhere
to be grown and fattened and sold as meat at Safeway.

Those heifers that don't get pregnant often end up on plates closer to
home.

The Diablo Trust brought in the cattle Friday morning by horse and
all-terrain vehicle for a meeting and a presentation on Anderson Mesa, as
artists sketched and took photos.

For the Metzger family, this area on Anderson Mesa has been a ranch since
1894.

"We garden on a landscape scale is all we do," said Kit Metzger.

The motivation to try something different was partly born from the idea
that she might be able to run more cattle on the land.

PLOTS SURVEYED YEARLY

So after agreement, about 30 researchers (counting undergraduate and
graduate students) surveyed the land on the same plots yearly, counting
plants at specific points.

The experimental areas heavily grazed produced more biomass (some plants
began growing more quickly), but they were also much more vulnerable to an
invasive plant, cheatgrass, that can take over a landscape and burn wildly.

The non-grazed areas didn't grow more plant material faster.

Most surprising of all: The areas grazed at a moderate level produced food
well and had the most diverse plant life of any area, the most
biodiversity.

"It's really not about the cows," Sisk said. "It's about how long the cows
are out there, how intensively the cows are out there, and more than
anything, it's climate."

No matter how they were grazed, all of his plant plots took a major dive
when the ranch ran dry in 2002, Sisk said.

There are also some factors that help confound an experiment, in that this
has been ranchland for more than a century. No one knows exactly all that
might be different if that were not the case.

And this is a range for wildlife, too.

"The results are many, and varied, and don't lend themselves to ideological
positioning," Sisk said.

Mostly, Sisk contends that it's important for researchers to take up
debates over how best to manage land to inform decision-makers amid climate
change, including on lands already being used for agricultural or some
other similar purpose.

"The debate about grazing is changing as the environment changes," he said.





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