January 10, 2007

Crawling to safety

Researchers to help desert tortoise dodge tanks, disease to find shelter

Andrew Silva, Staff Writer
San Bernardino Sun

They're snug in their burrows for the winter, but come spring, scores of desert tortoises will be picked up and moved to new homes.

After nearly two decades of controversy, often dubbed "the tortoise vs. the tank," the Army got permission in 2000 to expand its training grounds at the National Training Center at Fort Irwin, north of Barstow.

But that was contingent on making sure the tortoise had a chance to survive.

The Army has argued that it needs the extra land to conduct the most realistic training possible as it prepares its soldiers for combat.

But the expansion area to the south is home to one of the strongest populations of the threatened reptile.

Moving tortoises is a relatively new technique that biologists used to worry about, especially with the prevalence of upper-respiratory disease that has decimated some populations.

The Fish and Wildlife Service has been studying how tortoises in Nevada fare after having been relocated.

"There's no difference in the mortality of resident tortoises and those that have been moved," said Mickey Quillman, natural and cultural resources manager at Fort Irwin.

Tortoises hibernate all winter, so in the spring biologists will start tracking down the animals that are in the Army expansion area.

The animals will be moved south to 12 one-square-mile areas that have been studied to make sure they're suitable. And about 24 miles of tortoise fence will be erected along the north side of Interstate 15.

Each animal will be equipped with a transmitter, and any found to have upper-respiratory disease will be quarantined, Quillman said.

This comes at a time of renewed efforts to study and save the reclusive animal after criticism that there are major gaps in knowledge.

In a recent paper, one leading biologist found scientists don't always know which strategies do the best job of helping the iconic reptile.

"There's a lot of gut feeling we go on about what works and what doesn't," said William Boarman, a biologist who recently co-wrote a paper on the subject. "There have been a lot of actions taken in an attempt to protect the desert tortoise, but there's very little follow-up on what is working."

Boarman will also be involved in Fort Irwin's relocation effort.

His research agrees with a 2002 report by the Government Accountability Office, which found that scientific information on the tortoise was sorely lacking, despite more than $100 million being spent on the recovery up to that point.

That report triggered a renewed emphasis on tortoise research and recovery.

The gaps in knowledge are often cited by critics who bristle at restrictions on off-roading, grazing or development.

There just hasn't been enough money or staff to launch studies on recovery projects, officials said.

Still, many of the steps taken to protect the tortoise clearly make sense, even if there haven't been detailed follow-up studies on certain tactics, Boarman said.

For example, it's well documented that putting fences along highways has reduced the number of tortoises killed by vehicles, he said.

A trickier example would be the unpopular step of closing certain dirt roads to off-roaders. Even if there were a well-designed study, it would be tough to tell if such a closure made a big difference, Boarman said.

That's because the tortoise is notoriously difficult to study. One reason is its human-length life-cycle. It doesn't reach reproductive age until its mid-teens and can live to be 50 to 80.

The other problem for researchers is the tangled array of threats faced by the animal - loss of desert land to development, upper-respiratory disease, ravens that eat young tortoises, illegal off-roading, and non-native grasses that have brought devastating wildfires to the desert.

Despite those caveats and limitations, there is plenty of action among scientists and agencies.

The tortoise was listed as threatened in 1990, and a recovery plan was drafted in 1994.

The Fish and Wildlife Service is updating that 12-year-old recovery plan, and in response to the GAO report, the agency established a Desert Tortoise Recovery Office.

Even dogs are being brought into the mix, as one scientist is conducting studies to see if man's best friend can help researchers find the slow-moving, reclusive beasts.

What scientists know already can be discouraging. Most populations that have been studied for a long time have been declining, scientists said.

It appears the animals are gone from much of the desert, including Victor Valley, Palmdale and Lancaster, said Ed LaRue, a biologist who has studied the tortoise extensively, including work for the West Mojave Plan, which sought to protect roughly 100 species while allowing development to move forward.

"We did 4,000 square miles of transects and 6,000 miles of walking to find less than 300 animals," he said. "We found more than 1,000 dead ones. ... It's pretty dismal."

One bright spot is the Desert Tortoise Natural Area near California City between highways 14 and 395, north of Highway 58.

Basically a 40-square-mile, fenced-in sanctuary, it keeps out off-roaders, livestock, and other disturbances.

After surveying 350 square miles, scientists found 14 young tortoises - 13 of them within the fence - indicating successful reproduction is going on, LaRue said.

Young tortoises are the best indication the species has a chance to recover.

On the positive side, he said, even when developers or agencies get permission to kill a certain number of tortoises, usually only a tiny fraction are actually lost, with hundreds and hundreds moved out of harm's way, he said.

Fort Irwin sees only three to five tortoises a year killed accidentally.

Efforts to save the tortoise can't wait for definitive scientific proof that a particular action guarantees improvements, scientists said.

"You can wipe out a tortoise population quickly, but having it increase takes a long time," said Roy C. Averill-Murray, coordinator for the Desert Tortoise Recovery Office in Reno, Nev.

It will have to be a future generation of scientists who write the final chapter on the tortoise. Whether that's a happy ending remains to be seen.

"It's going to take a long time, even if we start doing good things," said Averill-Murray. "It'll take a while to get the populations back and hopefully toward delisting."


  • Official California state reptile
  • Listed as threatened in 1990
  • Difficult to gauge species recovery because of long life span of 50-80 years
  • The species upon which most desert preservation efforts focus
  • Once common throughout the deserts of Southern California
  • Reproductive age starts between 12 and 20 years old
  • Can grow up to 15 inches long and can go up to a year without water


  • Lives in creosote bush scrub and Joshua tree woodlands
  • Digs burrows in soft sand in desert valleys or in the gently sloping bajadas coming off the mountains
  • Activity peaks in spring and fall, followed by a long winter hibernation