Sonoran desert tortoises face threats, but feds won't list the species as threatened
Brandon Loomis
The Sonoran desert tortoise population is stable and not in need of protection under the federal Endangered Species Act, the U.S. Fish and Wildlife Service said Monday.
The tortoises, native to Arizona and northern Mexico, are exclusively land dwellers that grow shells of up to 15 inches in length. They are similar to Mojave desert tortoises, which have felt the effects of growth in Las Vegas and southwestern Utah and are federally protected as a threatened species.
Sonoran desert tortoises face numerous threats, according to the wildlife agency, including the spread of nonnative vegetation that alters fire cycles, human development, harassment and drought.
“While several of these threats, mainly development and drought, may increase in scope or severity over time, the species and its associated habitat are projected to remain at levels that do not threaten the survival of the Sonoran desert tortoise in the foreseeable future,” the agency’s Southwest regional office said in a statement.
Some 72% of the tortoise’s habitat in Arizona is managed by natural resources agencies or tribes, and tens of thousands of adult tortoises still roam their small territories on the desert, retreating into burrows to escape the summer heat.
The government first determined the tortoise’s status did not warrant its listing as a threatened species in 2015, but conservation groups sued to block that decision. A federal judge in 2020 ordered a new review, resulting in Monday’s decision.
One of the plaintiffs in that case, Western Watersheds Project, said it would review the documents and population models associated with the decision before deciding what to do next.
“We’re hopeful that they’re correct,” said Cyndi Tuell, the group’s Arizona and New Mexico director, “but we’re worried that (the decision) might have put the tortoise on a collision path with extinction.”
Specifically, she said, officials seem to have ignored the threat from livestock grazing, which her organization also sued over when the federal Bureau of Land Management proposed allowing livestock on the Sonoran Desert National Monument southwest of Phoenix. That lawsuit is still pending.
Cattle tend to compete with tortoises for spring greenery, and can damage their habitat, Tuell said. Drought and climate change may worsen the damage.
“It’s huge areas that are being destroyed,” she said.
Regardless of its federal legal status, the Sonoran desert tortoise enjoys protection in Arizona state law. It is illegal to harm, capture or collect wild tortoises, or to release a tortoise that has been held in captivity because of the risk of disease or behavioral changes.
The Arizona Game and Fish Department supports a tortoise adoption program, for tortoises that are either displaced or surrendered from captivity. Adopting is a long-term commitment, as the animals live 80 years or longer.
Brandon Loomis covers environmental and climate issues for The Arizona Republic and azcentral.com. Reach him at brandon.loomis@arizonarepublic.com or follow on Twitter @brandonloomis.
Environmental coverage on azcentral.com and in The Arizona Republic is supported by a grant from the Nina Mason Pulliam Charitable Trust. Follow The Republic environmental reporting team at environment.azcentral.com and @azcenvironment on Facebook, Twitter and Instagram.