Taxpayers will be forking over $50 million to have the Marines remove nearly 1,200 tortoises from future training grounds in the Mojave Desert, but similar efforts in the past have proven disastrous, say environmentalists.

The desert tortoises, already under stress from drought, disease and human interference, will be airlifted later this month from 130,000 acres surrounding the Corps' Air Ground Combat Center. The center is undergoing an expansion to facilitate live fire and maneuver training for full-scale Marine Expeditionary Brigade-sized elements.

"The situation makes us feel like we'll have to write off California's Mojave population." — Glenn Stewart, Desert Tortoise Council

"This spring, the Marine Corps will translocate approximately 1,180 desert tortoises in order to safeguard the animals coming from lands newly acquired through an NDAA-mandated (National Defense Authorization Act) land withdrawal that supports Marine Corps-mandated training requirements," base spokesman Capt. Justin Smith wrote in an e-mail to the Desert Sun.

The area slated for expansion is in prime tortoise habitat, and the number of breeding adults has dropped by about 50 percent over the last decade, according to a recent survey by federal biologists.

Some environmentalists are against the pricey effort to relocate the tortoises, which can stress the animals and leave them vulnerable to dehydration, predators and human interaction, they said.

"I wish the U.S. Fish and Wildlife Service would get some backbone and say it can't permit another tortoise translocation by the military," Glenn Stewart, a biologist and member of the board of directors of the Desert Tortoise Council conservation group, told the Los Angeles Times. "The situation makes us feel like we'll have to write off California's Mojave population."

In 2008, the Army moved 670 tortoises from its National Training Center near Barstow to new homes in the western Mojave. That $8.6 million effort proved disastrous when it was learned that a large percentage of them died within a year, many eaten by coyotes.

Brian Henen, a biologist and head of the Marine Corps' translocation effort, told the Times the project's ample budget and commitment to monitor the tortoises for 30 years "demonstrates how much we care about this species."

The plan, approved by the U.S. Fish and Wildlife Service, will utilize 100 biologists who will capture 900 adult tortoises and put transmitters on them before releasing them on nearby public lands. Another 235 hatchlings raised in pens at the base also will be relocated once they are strong enough to survive on their own. The project will take an estimated two to four weeks to complete, officials said.

The Combat Center raises the hatchlings in its 6-acre Tortoise Research and Captive Rearing Site, which is operated jointly with UCLA.

The desert tortoise is classified as a threatened species because its numbers have declined rapidly over the past few decades due to predators and disease. Soft shells leave young tortoises vulnerable to predators ranging from ants and ground squirrels to ravens and coyotes.