Can we save Mojave desert tortoises by moving them out of harm’s way?
Feds aim to save threatened tortoises by relocating them away from development
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A desert tortoise in Joshua Tree National Park, in California's Mojave Desert.
David M. Barron/Oxygen Group -
An adult desert tortoise crosses the center line of a road in the Mojave Desert.
David Lamfrom -
A male desert tortoise (Gopherus agassizii), covered with transmitters, near Palm Springs, California, where wind energy facilities are just one of the threats the species faces.
Jeffrey Lovich, USGS -
Kristin Berry, tracking desert tortoises in the Mojave last April. Her research helped inspire the reptile's listing as an endangered species.
Emily Green -
Marines wait for a desert tortoise to move off the road on the grounds of the U.S. Marine Corps' Air Ground Combat Center at Twentynine Palms, California.
AP Photo/Reed Saxon -
Roy Averill-Murray, who oversees desert tortoise recovery for the U.S. Fish and Wildlife Service, releases a desert tortoise at the Nevada National Security Site (the former Nevada Test Site) last September.
AP Photo/Ronda Churchill, Las Vegas Review-Journal
Kristin Berry's khaki hat flaps in the wind as she bends to inspect the skeleton of a desert tortoise. Remnants of its head and neck are still attached to the carapace, and bleached bones protrude from it. It's been dead for about four years, she suspects, and "appears to have died in a relaxed position," she says, "with its legs out." That suggests starvation and dehydration, but the 70-year-old biologist can't be sure.
It's the second week of April, when wild tortoises typically emerge from hibernation to forage on the spring wildflowers that briefly brighten the Mojave Desert. Berry –– who does long-term research on the desert tortoise for the U.S. Geological Survey –– is the acknowledged authority on where the now-threatened reptiles once thrived.
The rock outcropping where she stands is not far from I-15, halfway between L.A. and Las Vegas. Basalt hills rise to the north and west, and a cavalcade of power lines runs south. To the east, ORV tracks surround a makeshift bull's-eye riddled with bullet holes and what remains of a desert tortoise burrow. An empty Coors can is lodged in the burrow's entrance.
The ex-tortoise next to Berry wasn't hatched here. The U.S. Fish and Wildlife Service moved it and about 600 others 40 miles from their native range near Barstow, Calif., when the Army's Fort Irwin was expanded in 2008. Berry has been tracking it, and 157 other displaced tortoises. So far, perhaps half of the relocated animals are still alive. Nobody knows if that is good, bad or typical, or if the decline will continue. Berry's study will pit her carefully accrued survival data against the increasingly popular idea that desert tortoises can be protected, not by diverting development, but by moving animals.
This process is called "translocation." Since the desert tortoise came under Endangered Species Act protection in 1989, translocation has become the default solution to conflicts between people and tortoises. Thousands of tortoises have been moved to make way for modern Las Vegas, and for other desert development projects. Now, thousands more may be dug up to fast-track industrial-scale solar and wind farms throughout the Mojave.
"It's an incredibly depressing, sad story," says Defenders of Wildlife lawyer Mike Senatore. "I think the approach is basically, 'We can't say no to anything. We have to allow renewable energy projects to go where they shouldn't go. We have to allow off-road vehicles. We have to allow military expansion and housing. So we either pave over tortoises that are there, or we go out and pick up the ones we can find.' "
Increasingly, the Fish and Wildlife Service acknowledges that it's moving a lot of turtles and needs to do more to ensure they survive. The agency's Desert Tortoise Recovery Office coordinator, a 45-year-old biologist out of Arizona named Roy Averill-Murray, and his supporters believe translocation can become a pillar of conservation, not just as a way to protect tortoises from development, but also as a way to boost populations. A long history of disturbances, from grazing to off-road vehicles to invasive plants, is steadily extirpating the species, even in places that haven't been swallowed by housing or other projects.
Berry is well aware of the translocation push -- and dismayed by it. Her research helped inspire the reptile's original Endangered Species Act listing, and she wrote much of a now-discarded 1994 recovery plan that emphasized preserving habitat and considered moving the animals a tool of last resort, noting that it may prove useful "once translocation techniques have been perfected."
In 2004, the Fish and Wildlife Service brought in Averill-Murray and a new team to rewrite the 1994 plan. The revised plan, released in 2011, sees translocation as central to recovery, pointing out that recent efforts have been more successful than earlier attempts. No longer are animals just dropped in the desert; researchers often put up temporary fencing to keep tortoises from going back home, and dig new dens with the same orientation as the old ones –– even sprinkling them with sand and feces from their former homes.
The 2011 plan also requires the creation of new guidelines and protocols for translocation. Averill-Murray is now working with biologists from the San Diego Zoo to improve the handling and resettlement of animals displaced by development. The agency also plans to start repopulating public land near Las Vegas, using unwanted pets dropped off at a facility originally meant to house displaced wild tortoises.
But Berry remains skeptical. There are too many unanswered questions, she says. Will local population genetics get muddied? What about the animals' strong homing instincts and the impacts on resident tortoises? Last year, Berry and other independent scientists prepared a report for the Desert Renewable Energy Conservation Plan, a state and federal plan to develop solar power while protecting wildlife. It concluded: "In general, moving organisms from one area to another ... is not a successful conservation action and may do more harm than good to conserved populations by spreading diseases … increasing mortality, and decreasing reproduction and genetic diversity."
Scientists generally agree that translocation has negative consequences for wildlife, especially animals as intimately tied to their homes as tortoises. "They know where every little water catchment is," says Brian K. Sullivan, an Arizona State University professor who specializes in herpetology. "They'll travel hundreds of meters to reach them when it rains. And they have strong social structures. No wonder they're traumatized when we wrench them out of their landscape and drop them somewhere else."