Desert battles a growing threat: Buffelgrass

Desert battles a growing threat: Buffelgrass

06 November 2010

USA — A dozen inmates make their way up a sharp slope near Superior. They are dressed in orange and carry blue plastic bags, bent to their work as the sun climbs and a breeze moves along the ridgeline.

Patti Fenner, Noxious Weed Program manager for Tonto National Forest, supervises the inmates as they tear into the hillside with pickax-type tools used by firefighters and Forest Service workers, pull up clumps of buffelgrass and shove them into the bags.

Fenner’s job is to slow the spread of invasive plants over thousands of acres in the Tonto, plants such as buffelgrass and fountain grass, which threaten Sonoran Desert ecosystems.

Researchers have recorded buffelgrass fires at 1,300 to 1,600 degrees, almost three times hotter than fires fueled by native vegetation, with flames shooting 12 to 18 feet high. In one experiment, 99 percent of the available fuel was burned. Some researchers fear the Sonoran Desert could be lost if such fires become commonplace.

Fenner has no staff and no budget, so she spends much of her time seeking grants and making trades, like the one that allows her to borrow this crew of inmates for a day. They have been convicted of non-violent crimes and are cleared to work outside prison walls for 50 cents an hour. Fenner suspects they would rather spend their time outdoors than in the prison yard, but they are not exactly rugged outdoor types. The day starts to warm and the work goes slowly.

A couple of inmates sit down when they think nobody is paying attention. The rest are spread along the hillside. One wears a ragged white shirt under his orange prison-issue T-shirt. By the end of the day, the crew will pull 780 pounds of buffelgrass. They have pulled as much as a ton in a day.

“When you’ve got 12 guys you can get a lot of work done,” Fenner said.

She wears leather gloves and boots, a bandanna, earrings and a Forest Service uniform. A hummingbird buzzes nearby, traffic hums on the highway below, the wind blows and the air is thick with pollen. She sips water from a bottle that started out as a solid block of ice and melts as the sun climbs.
Public lands endangered

The spread of buffelgrass has alarmed people who work in Arizona’s national parks and monuments because it grows thick, burns hot and crowds out native plants. Some say the Sonoran Desert could be transformed into a habitat more like an African grassland. Others point out that species unique to this region, like the desert tortoise, will suffer.

Buffelgrass was introduced to southern Arizona in the late 1930s for erosion control and livestock forage. Public-land managers didn’t see any problems with it, partly because they weren’t looking for any. So it spread. By the 1980s, buffelgrass began to show up in Organ Pipe Cactus and Saguaro national monuments.

In the past decade, however, researchers have learned more about the damage buffelgrass can cause.

More grass means more fuel, from two times to 4,000 times more. Some fear that buffelgrass fires will threaten such plants as saguaro, barrel and cholla cactus and paloverde trees. These native plants, which have not evolved with fire, struggle in the aftermath of such blazes.

“It has the capability of basically sterilizing the desert soil,” said Mark Lambert of Ironwood Forest National Monument. By this, he means the soil will no longer support native plants. Buffelgrass, however, can still grow in such an environment.

By the time researchers learned of these dangers, they realized that buffelgrass was already growing thick in southern Arizona.

Various agencies started programs to combat the invasive plant and have since combined their efforts. In April, U.S. Rep. Raul Grijalva, D-Ariz., held a hearing on buffelgrass. Richard Brusca of the Arizona-Sonora Desert Museum in Tucson said in written testimony that the plant could transform the native landscape into a land without saguaro cactus.

“We have already driven dozens of Sonoran Desert plants and animals to extinction,” Brusca wrote, “and hundreds more are now on the verge. The invasion of African buffelgrass is pushing us to a tipping point, where the entire Sonoran Desert ecosystem could collapse.”

Unless action is taken immediately, Brusca wrote, the desert museum will be a museum of what used to be.
Sonoran Desert fires

For centuries, large fires were rare in the Sonoran Desert because native grasses and bushes grow in clumps. If a fire did occur, it burned at low temperatures and flamed out quickly. Fires may have occurred only every 250 years.

Buffelgrass harms the desert in a variety of ways. It robs native plants of moisture. At first it grows in clumps, but as the native plants die out, the buffelgrass grows taller and thicker. Trees and saguaro cactus may remain, but they are vulnerable to fire.

So far, Arizona has been spared the apocalyptic buffelgrass fire that researchers fear, but such fires have happened in Mexico and Hawaii, and Arizona has seen another invasive grass, red brome, fuel destructive blazes. Red brome was a major catalyst in the Cave Creek Complex fire that burned 248,310 acres in 2005 and was so big that it could be seen from space.

Some worry that buffelgrass will pose a threat not only to plants, but to the birds and reptiles that utilize them, such as the desert tortoise, various species of lizards and Gambel’s quail.
Killing buffelgrass

Killing buffelgrass is time-consuming and labor-intensive. You must pull it up by the roots and bag it so the seeds don’t spread. Some agencies apply herbicide next. Then they pull some more. Repeated attempts can be successful at eradicating the plants. Hillsides and washes have been reclaimed.

The Bureau of Land Management has been successful using volunteers to help control buffelgrass at Ironwood Forest.

“It is essentially our Number 1 priority right now, the eradication of buffelgrass,” Lambert said. “It’s a huge threat, in terms of native species, and it’s actually a problem we think we can get a handle on.”

Marilyn Hanson became so alarmed about the spread of buffelgrass when she started pulling it at the Arizona-Sonora Desert Museum that she joined the Sonoran Desert Weedwackers.

There are now a handful of such groups in southern Arizona and one in Phoenix.

“It is possible to knock it back,” said Hanson, who serves on the executive committee of the Southern Arizona Buffelgrass Coordination Center, a group that organizes volunteers and educates people about invasive plants.

The volunteer groups are one of the few resources that federal agencies have to combat the spread of buffelgrass.

A lack of infrastructure, funding, staffing and cohesion among government agencies has made eradication difficult, but agencies have begun to work together, share volunteers and plan ahead, said Travis Bean, a principal research specialist at the University of Arizona.

“Buffelgrass is not going to stay on your side of a barbed-wire fence,” Bean said.
Tonto Forest work

Fenner talks about her work and points out native plants while the inmates work. A guard moves uphill and the inmates start working a little harder. Full bags are carried to a trailer below. Partially filled bags flap in the breeze.

Fenner pulls a withered sprig of brittlebush and says it probably died because the buffelgrass beside it took all the moisture.

The hilltop still has some diversity of plant life: fairy duster, three-awn grass, fluff grass, jojoba and cholla cactus. Paloverde trees splash yellow across the desert.

When Fenner accepted the job, the first thing she did was inventory the plants found in the forest’s various districts. So far, she has found about 65 invasive plants.

One of these, the camelthorn, can grow through concrete. Its thorns can puncture tires. Camelthorn growing near roads can crack asphalt. It has given the Arizona Department of Transportation a lot of trouble on the Navajo Reservation, Fenner said.

Other plants can kill horses. And, of course, there is always the danger of fire. Buffelgrass has spread to public land near some of Tucson’s most expensive properties. The hillside where the inmates work overlooks Superior, one of the communities that Fenner said is growing more concerned about invasive plants.

The day warms, and the inmates pull weeds, shove them into bags and carry them down the hill.

Nobody is sure if it’s possible to eliminate buffelgrass as a threat, but everyone involved seems to agree on the consequences of doing nothing.

It’s hard to get people excited about invasive plants, Fenner says, especially when they haven’t entirely taken over yet.

“If you wait until that happens, it’s too late.”

24. November 2017/by GFMCadmin