YUMA, Ariz. - It's 90 degrees outside and I'm freezing. Border Patrol agent A.L. "Al" Casillas revs the engine and blasts the air conditioning as we drive through Arizona's Sonoran Desert, just yards from the Mexican border. We spin through the fine sand of the Barry M. Goldwater Air Force Range, past low-lying creosote bushes, purple belly flowers and jagged mountains. With less than two inches of rain here per year, animals depend for survival on rainwater that collects in the shallow depressions of slickrock.

The landscape of sand and sweltering heat seems far away from the plush interior of Casilla's agency truck. He sums up the desert: "Everything pretty much survives on its own and maintains a status quo."

But life on this remote stretch of the border is anything but status quo. Since 1996, Border Patrol activity has boomed in the Sonoran Desert. Three years ago, agents arrested 150,000 people trying to cross into Arizona from Mexico. In 1999, the agency expects to arrest over 400,000.

The rush is the result of Operation Gatekeeper, a sweeping agency initiative aimed at reducing illegal immigration through metropolitan areas like San Diego, Calif., where the agency has built new fences and roads, installed motion sensors and floodlights and hired an army of new agents.

Operation Gatekeeper has worked. Arrests in San Diego have dropped by a few thousand per day. But the problem has not disappeared. "Mexicans are still desperate to enter the U.S.," says agency information officer Rob Daniels. Mexicans who once would have tried to come through San Diego or El Paso, Texas, are now "funneled" into the Sonoran Desert, he says.

This desert is home to the endangered Sonoran pronghorn antelope, the flat-tailed horned lizard and other animals that are barely hanging on in the border country.

Environmentalists fear that the wave of immigrants and chaos of Border Patrol trucks and helicopters may overwhelm the desert wildlife. Backed by the Endangered Species Act, they hope to change how the Border Patrol does business, though it is an agency that in the past has had little time or patience for the land.

People come first

As the sun goes down and the desert cools, Casillas and I visit Yuma Border Patrol headquarters, which doubles as a holding tank for undocumented immigrants. Before returning immigrants to Mexico, agents bring them here to fill out paperwork.

Inside the building, benches line the concrete walls of two small waiting rooms - one for men, the other for women. Today, two Mexican women sit drinking apple juice and speaking Spanish in hushed tones. Most immigrants are nabbed while on their way to Tucson or Phoenix. They carry a few belongings, rarely enough water, and a desperate hope for a better-paying job and a better life.

It is a hope they may risk everything for: The walls of the waiting rooms are plastered with signs in Spanish that warn of the dangers of crossing the desert. In the office, a photo shows two bodies lying in the desert sand, charred from the sun's rays. This summer, more than 30 people died from heat and exhaustion while trying to cross the desert from Mexico.

The dangers of the desert sun have turned the Border Patrol from boundary cops into search and rescue teams. And to handle the deluge of immigrants, the agency has brought approximately 900 new Border Patrol agents to southern Arizona since the advent of Operation Gatekeeper, most from the East Coast or Texas. "For some of them it has to be quite a culture shock," says Casillas.

As agents arrive, they learn desert survival skills and how to help dehydrated desert crossers. But they get no land-ethics training course, no maps of Bureau of Land Management roads and, until recently, no information on plants and wildlife.

"If you're short on man power and short on everything else, you can't justify attending to a function like that," explains Casillas. "The force serves as a deterrent for undocumented immigrants; that's our primary function. A life to us is a lot more important than a moss."

Although field managers are now getting some instruction on pronghorn habitat and sensitive desert plants, Casillas explains that to the average agent, the message is hard to understand. "Agents will get a memo about being more environmental and think, "Give me a break, what am I ruining by going three inches off the road? I'm busting my butt for you; is this all you have to worry about?"

No excuse for ignoring the land

"I recognize that (Border Patrol agents) are in a difficult position," says D.J. Schubert, hefting a stack of articles 10 inches high onto the table between us. "Their duty is to defend the border, but that duty shouldn't give them carte blanche to abuse the environment."

Schubert is a biological consultant for the nonprofit Defenders of Wildlife. We're sitting in a crowded Phoenix restaurant, talking about the changes that have come with the booming activity on the border. The stack of papers is his arsenal. It contains reams of information on the effects of Border Patrol and Air Force activities on the Sonoran pronghorn antelope, which has been on the Endangered Species list for over 30 years.

There are only 125 Sonoran pronghorn antelope left in the United States. This rare subspecies of pronghorn lives in the alluvial valleys between granite mountains in southern Arizona and Mexico. The leggy, buff creature is one of the fastest mammals in the world and can run at speeds of up to 60 miles per hour. They are easy to scare and hard to observe.

Border Patrol helicopters fly over pronghorn habitat every day, says Schubert, causing the animals to scatter. The noise causes their heart rates to increase, he says, and fawns separated from their mothers often die. As recently as last July, another pronghorn was found dead just a quarter of a mile from an Air Force strafing target.

To pluck the pronghorn from the Endangered Species list, the Fish and Wildlife Service is trying to raise the population to 300, and keep it there for five years. But Schubert and Defenders of Wildlife say there is no way to achieve this goal if the Border Patrol continues to batter the pronghorn's habitat. The group is in the process of suing the agency, saying it isn't in compliance with either the Endangered Species Act or the National Environmental Policy Act.

It's not the first time the Border Patrol has been accused of breaking the law. Fish and Wildlife sent the Border Patrol a notice in 1996 that it was breaking the National Environmental Policy Act. The Border Patrol has never completed a biological opinion, an evaluation of activities required by all agencies that operate in an area inhabited by an endangered species. "They are basically operating without a permit," says Chandra Rosenthal, head lawyer in the Defenders lawsuit. Although the Border Patrol has submitted two biological assessments since the notice was sent, the Fish and Wildlife Service has rejected both as incomplete.

"As part of ESA, all agencies have an affirmative to develop conservation and recovery programs," says Rosenthal. Because of this mandate, all agencies in the Sonoran Desert have been conducting monthly pronghorn recovery meetings. All agencies, that is, except the Border Patrol. "They're not taking part in even the small things that the other agencies do," Rosenthal says. Last March, Defenders filed their complaint with the Border Patrol. The Border Patrol is expected to file a formal defense to these allegations. Defenders will then have another opportunity to respond.

Steering a juggernaut

The conflict doesn't end at the Arizona borderline, says Sierra Club activist Edie Harmon, who has lived in California's Imperial County, between San Diego and Yuma, for over 20 years. "There have been times at night when I have thought, this must be what it's like to live in a war zone, there are so many planes and helicopters."

Although she has often seen Border Patrol vehicles in designated wilderness areas, she says she feels helpless to do anything about it. "There's no point calling a BLM ranger out," she says, "when the person breaking the law is another government law-enforcement agent."

Mark Jorgensen, the resource ecologist for Anza-Borrego Desert State Park and the Colorado Desert District, shares Harmon's frustration. Jorgensen is concerned about the flat-tailed horned lizard, found throughout southwest Arizona, southeast California and portions of Sonora and Baja, Mexico. Proposed for listing as a threatened species in 1993, the lizard is still not protected, and its numbers are dropping.

Flat-tailed horned lizards are beige or cream-colored and hard to distinguish from the sand and soft disturbed soil they like, so they're attracted to the Border Patrol's "drag roads." Agents create the roads by dragging tires behind trucks, wiping the sand smooth so they can spot new footprints. But Jorgensen says vehicles that rumble down drag roads also crush lizards.

"We're fairly naive when it comes to the ecosystem of the lizard," he admits. "We do know that if you're going to be laissez-faire about an entire species, you're acting recklessly."

But Jorgensen says the Border Patrol has been unresponsive to his concerns. "They (Border Patrol agents) drive off-road, they drive cross-country all the time. Who do you call? Who do you talk to in a bureaucracy?"

"It's like having two federal agencies working at opposite ends," says a BLM staffer who doesn't want to be identified. "But we don't want to get in a fight with another federal agency. In the meantime, I'm watching a wilderness area be destroyed."

Changing with the times

Still, some people say the Border Patrol can change. "I've seen an immense improvement in environmental compliance and it's continuing to get better," says Chris Bates. She has worked for five different federal agencies in the Southwest deserts, and her job at the Bureau of Reclamation involves reviewing the Border Patrol's environmental impact statements and other National Environmental Policy Act (NEPA) documents.

"A lot of defense agencies thought they were exempt back in the 1980s," says Bates. "But practicing NEPA and caring for the environment has become a way of life now."

The first inklings of this change lie in Washington, D.C. Three years ago, the Immigration and Naturalization Service detailed Deborah Hood to work for the Border Patrol as an environmental officer. Her function is to help the agency fall into line with environmental laws.

Hood is one of only three environmental officers in the 7,500-employee agency, but she says they're making progress. The agency is developing training videos for agents "to make them a little more aware of their surrounding areas," she says, and conducting a biological assessment of the Sonoran Desert. As a defense agency, Hood says, the Border Patrol could have waived the Endangered Species Act, but it chose not to.

"I honestly believe we're not that bad of an agency," says Al Casillas. "We know we have to change with the times and we're trying to make changes when we can."

Environmentalists aren't waiting around. "Agencies respond to friction; if you don't push them a little, they don't react," says Bill Broyles, whose Tucson-based nonprofit Friends of the Cabeza is spearheading a movement to turn a chunk of the Sonoran Desert, including a 124-mile stretch of the border, into a national park (HCN, 3/29/99). "We're just trying to get some results."

Rebecca Clarren lives in Seattle, Washington. She researched this story while working as an HCN intern.

You can contact ...

* Chandra Rosenthal, Defenders of Wildlife, 1101 14th St. NW, Suite 1400, Washington, DC 20005 (202/682-9400); www.defenders.org/; e-mail: crosenthal@defenders.org);

* Border Patrol Information Officer Rob Daniels, 1970 W. Ajo Way, Tucson, AZ 85713 (520/670-6871) or Agent A.L. Casillas, 350 W. 1st St., Yuma, AZ 85364 (520/782-9548).