Researchers Fear Southern Fence Will Endanger Species Further

Brian P. Segee, a Defenders of Wildlife staff lawyer, said the waiver decision will affect plants and animals in areas ranging from the Lower Rio Grande Valley National Wildlife Refuge in Texas to Arizona's San Pedro Riparian National Conservation Area.

"We're going forward blindly now, and we're going to be learning about the consequences for years to come," Segee said in an interview.

The legal and scientific battle over the fence -- which will continue despite the administration's waivers -- highlights the reality that prized wildlife species are not respecters of international borders.

While popularly perceived as a barren desert, the landscape that straddles the border includes some of the world's most diverse terrain, such as Arizona's Sky Island area, which features isolated mountains surrounded by grassland or desert. Dotted with evergreen trees at higher altitudes, the region attracts jaguars as well as the Sonoran pronghorn and bighorn sheep that regularly crisscross between the United States and Mexico.

Farther to the east, the Lower Rio Grande Valley is home to one of the last free-flowing rivers in the United States, as well as more than 300 butterfly species, more than 500 bird species and the ocelot, an endangered wild cat. Even though 95 percent of the brush habitat in the four counties encompassing the Lower Rio Grande Valley refuge has been eroded, it still boasts 17 federally endangered or threatened species -- more than the entire state of Louisiana.

"The significance of this area, biologically, is extraordinary," said Evan Hirsche, president of the National Wildlife Refuge Association. He said the administration completed a draft environmental impact statement about the fence in three months, a process that would normally take two to three years.

Ken Merritt, who served as project manager for the Lower Rio Grande Valley and two other wildlife refuges in South Texas before retiring in January, called Homeland Security's environmental assessment "a totally inadequate job. They just threw it together." One planned project on the west side of the Lower Rio Grande Valley refuge "basically cuts off wildlife from water," he added.

One of the most vulnerable species in the valley is the ocelot, a small hunter whose fur resembles that of a jaguar. Between 80 and 100 ocelots remain in South Texas, but their survival depends on access to water and getting to Mexico to breed with ocelots there, because the Texas population lacks genetic diversity.

"They're perilously close to going extinct," said Nancy Brown, a Fish and Wildlife public outreach specialist for the refuge. "You think of that irony, we need our cats to get into Mexico. Genetically, they're all starting to look like the same cat."

Homeland Security's assessments do mention ocelots and other imperiled species in brief passages. The draft environmental impact statement, published late last year, noted: "Habitat loss and fragmentation especially along the Rio Grande pose a critical threat to the long-term survival of the ocelot. Efforts are underway to preserve key habitat and biological corridors necessary for ocelot survival."

But Brown said the government has failed to accommodate the needs of ocelots and other species.

"Locally, we tried very hard to seriously make this fence a wildlife-friendly fence," she said. "When you've got a wall 27 miles long and 16 feet high, that's a tough one. It's really hard to make that wildlife-friendly. Whether you're an ocelot or an armadillo, when you bang into six miles of a concrete wall, you're in trouble."

Homeland Security's Kudwa said that agency officials tried to be sensitive to "both environmental and cultural artifacts" in the area, adding that by reducing the trash left by immigrants crossing the border, the barrier could improve the environment in some ways.

"We need to weigh the impact on the environment and the impact on human lives and our ability to secure the border," she said. "That illegal activity does not stop at the border as we have this endless debate."

Scientists are continuing to debate what will happen. A cadre of Mexican scientists is working with U.S. researchers to try to assess the populations that mix across the border even as fence construction is moving forward.

Rurik List, an associate researcher at the Institute of Ecology of the Universidad Nacional Autonoma de Mexico, said that aside from the Great Wall of China, "never before has something of this scale been constructed. So nobody knows what will happen."