Habitat is a crucial factor in survivability of released tortoises

Date: August 31, 2016

Source: Zoological Society of San Diego

As conservationists work to recover endangered species populations, taking individuals that are maintained and protected under human care and reintroducing them into the wild, it becomes apparent that there is a great deal to learn about the science of species recovery. In a paper published in the recent edition of the Journal of Applied Ecology, a team of wildlife experts from San Diego Zoo Global, the U.S. Geological Survey, the U.S. Fish and Wildlife Service and the University of Nevada analyzed the effect of habitat quality on the survival and dispersal of released desert tortoises. Juvenile tortoises used in this study originated from eggs produced by females housed at the Desert Tortoise Conservation Center in Las Vegas. Ages ranged from 6 months to 4 years. The tortoises were translocated and monitored for one year, using radio tracking systems.

"The goals of the study were to help re-establish populations of this threatened and declining species, and to understand better what critical resources on the landscape are associated with the ability of young tortoises to survive and thrive," said Ron Swaisgood, Ph.D., director of Applied Animal Ecology at San Diego Zoo Global. Tortoises released in habitat that included appropriate vegetation, rocks and the presence of animal burrows had lower mortality rates than those released in areas where land features offered fewer options for predator avoidance. "Burrows created by small mammals represent critical components of desert tortoise ecology," said Melia Nafus, Ph.D., a researcher for San Diego Zoo Global and lead author of the study. "Supporting healthy rodent populations through habitat management may improve juvenile desert tortoise survival and recruitment." Another interesting finding of the study was that tortoises released on rocky ground were less likely to disperse away from the release site. "This finding probably relates to the tortoise's dependence on rocky substrate, as camouflage to hide from predators," said tortoise expert and co-author Todd Esque, Ph.D., from the U.S. Geological Survey.

Continued  

A Unique Pet: Desert Tortoises Up For Adoption - via Herp Digest

(KUTV) Utah wildlife officials are looking for adoptive homes for approximately 40 desert tortoises that can't be returned to their native habitat. 

"They make very good pets," said Lynn Chamberlain, southern Utah outreach manager for the Utah Division of Wildlife Resources. 

The Mojave Desert Tortoise is listed as a threatened species, making it illegal to capture or even touch them in the wild. If the DWR receives a tortoise that was removed from the wild by humans it is sent to live at a facility in Washington County.

Once in captivity, the tortoises cannot be returned to the wild, Chamberlain says, because they could possibly introduce diseases contracted while in captivity into the wild populations.

"It's better for somebody to adopt them than to let them die in a facility," said Cornell Christensen with the Red Cliffs Desert Reserve, an organization aimed at recovering the desert tortoise population. "Let somebody enjoy them for a few years."

Christensen says the reptiles are easy to care for and make for a great family pet. 

"Their demeanor is very, very calm and collect," he said. "They're not aggressive at all."

While they may be a low-maintenance companion, the desert tortoise requires commitment because they can live upwards of 90 years in captivity. 

"This is not like buying a gold fish," Chamberlain said. "If you get one of these tortoises for one of your grandchildren, that tortoise may be alive when that grandchild is a grandparent."

Those living in Iron, Kane and Washington Counties are ineligible to adopt the tortoises because of the risk that the tortoises could escape and reunite with the native tortoise populations. 

For more information about adopting a desert tortoise, you can get answers to common questions by reading the DWR's adoption booklet: http://wildlife.utah.gov/pdf/dt_adopt.pdf or by contacting the DWR at 801-538-4746 or by email to tortoise@utah.gov. 

By Ladd Egan

(Copyright 2014 Sinclair Broadcasting Group)

For video http://kutv.com/news/top-stories/stories/a-unique-pet-desert-tortoises-up-adoption-9476.shtml

Desert tortoise faces threat from its own refuge as BLM closes Vegas rescue center (Euthanize some of the tortoises) - via Herp Digest

By Associated Press, Published: August 25, 2013 

LAS VEGAS — For decades, the vulnerable desert tortoise has led a sheltered existence. 

Developers have taken pains to keep the animal safe. It’s been protected from meddlesome hikers by the threat of prison time. And wildlife officials have set the species up on a sprawling conservation reserve outside Las Vegas. 

But the pampered desert dweller now faces a threat from the very people who have nurtured it. 

Federal funds are running out at the Desert Tortoise Conservation Center and officials plan to close the site and euthanize hundreds of the tortoises they’ve been caring for since the animals were added to the endangered species list in 1990. 

“It’s the lesser of two evils, but it’s still evil,” said U.S. Fish and Wildlife Service desert tortoise recovery coordinator Roy Averill-Murray during a visit to the soon-to-be-shuttered reserve at the southern edge of the Las Vegas Valley last week. 

Biologists went about their work examining tortoises for signs of disease as Averill-Murray walked among the reptile pens. But the scrubby 220-acre refuge area will stop taking new animals in the coming months. Most that arrive in the fall will simply be put down, late-emerging victims of budget problems that came from the same housing bubble that put a neighborhood of McMansions at the edge of the once-remote site. 

The Bureau of Land Management has paid for the holding and research facility with fees imposed on developers who disturb tortoise habitat on public land. As the housing boom swept through southern Nevada in the 2000s, the tortoise budget swelled. But when the recession hit, the housing market contracted, and the bureau and its local government partners began struggling to meet the center’s $1 million annual budget. 

Housing never fully recovered, and the federal mitigation fee that developers pay has brought in just $290,000 during the past 11 months. Local partners, which collect their own tortoise fees, have pulled out of the project. 

“With the money going down and more and more tortoises coming in, it never would have added up,” said BLM spokeswoman Hillerie Patton. 

Back at the conservation center, a large refrigerator labeled “carcass freezer” hummed in the desert sun as scientists examined the facility’s 1,400 inhabitants to find those hearty enough to release into the wild. Officials expect to euthanize more than half the animals in the coming months in preparation for closure at the end of 2014. 

The desert tortoise is a survivor that has toddled around the Southwest for 200 million years. But ecologists say the loss of the conservation center represents a harmful blow in southern Nevada for an animal that has held onto some unfortunate evolutionary quirks that impede its coexistence with strip malls, new homes and solar plants. 

Laws to protect the panicky plodders ban hikers from picking them up, since the animals are likely dehydrate themselves by voiding a year’s worth of stored water when handled. When they’re moved, they nearly always attempt to trudge back to their burrows, foiling attempts to keep them out of harm’s way. They’re also beset by respiratory infections and other illnesses. 

No more than 100,000 tortoises are thought to survive in the habitat where millions once burrowed across parts of Utah, California, Arizona and Nevada. 

The animals were once so abundant that tourists would scoop them up as souvenirs. Many quickly realized the shy grass-eaters don’t make ideal pets. (For one thing, they can live for 100 years.) And once the species was classified as threatened on the endangered species list, people rushed to give them back. 

Former pets make up the majority of the tortoises at the conservation center, where they spend their days staring down jackrabbits and ducking out of the sun into protective PVC piping tucked into the rocky desert floor. Most of these animals are not suitable for release, either infected with disease or otherwise too feeble to survive. 

Averill-Murray looks as world-weary as the animals he studies. He wants to save at least the research function of the center and is looking for alternative funding sources. 

“It’s not the most desirable model to fund recovery — on the back of tortoise habitat,” he said.