Ocelots are collateral damage

Sept. 13, 2007 | McALLEN, Texas -- Sonia Najera walks under a canopy of ash and sugar hackberry trees, down a dirt path that ends at the water's edge of the Rio Grande. The spot is a mile from the tidal flats where the river mixes with the Gulf of Mexico after its journey from the Colorado headwaters. Najera, South Texas project manager for the Nature Conservancy, points to paw prints in the muddy river bank. "That's a canine," she says, "probably a coyote. That looks like badger; that's chachalaca for sure," she continues, describing a pheasantlike bird found in this southern tip of Texas.

Najera, a wildlife biologist, also looks for tracks of the ocelot, the endangered wildcat with a signature rosette camouflage that allows it to hunt in sun-dappled canopy forests. No tracks today, or most days. Once the ocelot hunted all the way up through the woodland areas of eastern Texas and into Louisiana and Arkansas. Now the only two remaining family groups in the U.S., fewer than 100 individuals, can be found here.

The ocelot is not the only rare creature carrying on a precarious existence in this unique corner of Texas. Although not as well known as Yosemite or Yellowstone, the Lower Rio Grande Valley National Wildlife Refuge offers a variety of species unmatched in the United States -- 500 bird species, 300 butterflies, 700 vertebrates. "This is one of the crown jewels of the national wildlife refuge system," says Carter Smith, Texas state director of the Nature Conservancy. Saving and restoring this area took $70 million in federal land acquisitions and three decades of work by the Nature Conservancy, Audubon Society and local communities. But now the victories could go for naught.

At issue is the Bush administration mandate to build 700 miles of fence along parts of the U.S. border with Mexico. It's part of the Secure Border Initiative, a Department of Homeland Security program first funded by Congress in 2005 to address border security. While the fence has stirred a bonfire of debate over terrorism and illegal immigration, the fate of the area's unique wildlife has been lost in the uproar.

In Texas, 225 miles of fencing will begin to be installed this fall. A large percentage of that fencing will be built in the valley along the unique river bank and habitat that follows the Rio Grande. It would cut across more than a dozen refuges and parks totaling more than 100,000 acres. Critics warn the fence and its accompanying patrol roads will sever critical wildlife corridors on the animals' natural territories. Animals depend on these corridors to reach mates, and seek food and water. If the fence is installed, says Martin Hagne, director of the nonprofit Valley Nature Center, "it will be a huge catastrophe." Hagne is a member of an unusual coalition of environmentalists, local farmers, ranchers and local business interests fighting the fence.

Construction is slated to begin later this year, and opponents are worried they won't have a democratic voice to stop it. Homeland Security Secretary Michael Chertoff has vowed to seek community input and consider local concerns. But while department spokespersons in Washington say the consultative process is under way, folks in the valley say they haven't been heard. Even biologists with Homeland Security's sister agency, Fish and Wildlife, say they don't know where the fence is going to run or what it's going to look like.

The most likely route for the valley fence would run along a 1935 earthen flood control levee. The levee follows a straighter course along the river than do the tortuously winding banks of the Rio Grande. In some places it comes within yards of the river and in others, the levee is a mile inland. While the levee makes an easy natural crossing for animals, the construction of a secure fence or even hard-packed patrol roads would create small islands of land between the fence and the river and interrupt the natural movement of animals to the river, where they feed.

Jody Mays is a Fish and Wildlife biologist who has worked with ocelots in the valley for a decade. She explains that the open areas created by the fence would further limit the ocelots' hunting range because the cats, marked for forest and night hunting, simply will not risk exposure in the open. "The ocelot cannot adapt to open areas," she says. "They're vulnerable because of their markings. If an ocelot's standing in the middle of a clearing, it's going to stick out like a sore thumb."

Mays has seen the ocelot population in the U.S. fall to just two groups. One is a group of 25 to 35 individuals that live on the Laguna Atascosa wetlands, and the other is a smaller group of 10 to 12 cats that occupy a large private ranch nearby. Even though the two groups are separated by only a few miles, they cannot reach each other because of the habitat fragmentation caused by development.

Mexico has a healthier population of ocelots and jaguarundi. But the Laguna Atascosa ocelots continue to decline because the lack of wildlife corridors prevents them from breeding with ocelots in northern Mexico. Some bilateral programs are under way with Mexico to reopen some of the historic wildlife corridors that cross the Rio Grande. But a border fence would probably render those efforts useless. The isolation of ocelots on the U.S. side is already showing up in health problems, and has been seen in the degradation of their DNA quality. Inbreeding is taking its toll. "A simple flu could wipe them out," Mays says.

Next page: The rugged terrain creates its own impenetrable fence