WildEarth Guardians

Thursday, October 9, 2008
Tortoise Racing Toward Extinction

Federal Protection Sought for Rapidly Declining Sonoran Desert Tortoises
Contact: WildEarth Guardians

PHOENIX - Today, WildEarth Guardians and Western Watersheds Project filed a petition requesting that the U.S. Fish and Wildlife Service (Service) list the Sonoran desert tortoise population under the Endangered Species Act and designate critical habitat to protect the animal. The Sonoran desert tortoise population has declined by 51% since 1987.

Severe population declines were documented in a recently completed report. The study, commissioned by WildEarth Guardians, found that desert tortoise populations are declining by about 3.5% per year throughout southwestern Arizona. Although to the untrained eye they may look similar, Sonoran desert tortoises show marked genetic and behavioral differences from tortoises found in the Mojave Desert. The Mojave Desert population was listed as threatened under the Endangered Species Act in 1990.

“Federal protection for the Sonoran desert tortoise is long overdue. The Service needs to list this endangered creature promptly so that it can board the legal ark the Endangered Species Act provides,” stated Dr. Nicole Rosmarino of WildEarth Guardians.

“In 1990, when the Mojave population of desert tortoises was listed, the Service declined to list desert tortoises east of the Colorado River on the grounds that they were less imperiled than their Mojave cousins. The dramatic declines we’ve seen in Sonoran desert tortoise populations since then now require swift action by the federal government,” stated Dr. Michael Connor of Western Watersheds Project.

The petition catalogues many threats that contribute to tortoise declines including disease, livestock grazing, mining, urban sprawl, use of off-road vehicles, border patrol activities, and a lack of adequate legal protections. Extended drought caused by climate change is an additional threat. Biologists fear that human activities combined with environmental stress may be increasing susceptibility to two diseases that are now becoming increasingly common among Sonoran desert tortoise populations. A disease epidemic led to emergency federal protection for tortoises in the Mojave Desert in 1989. Stated Connor, “The combined assault of threats such as development, cattle grazing, and disease are pushing Sonoran desert tortoises closer and closer to extinction.”

If listed under the Endangered Species Act, Sonoran desert tortoises would be protected from “take” (including killing and harassment) of individual tortoises, and the Service would have to develop a recovery plan to map out the steps that must be taken to reverse the declines. The Service would also have to identify critical habitat required by the tortoise so that it can be protected to aid the conservation and recovery of the species.

The Endangered Species Act requires the Service to issue an initial finding on the petition within 90 days.

“The Sonoran desert tortoise population has been slashed in half over the past two decades. The Service passed up an earlier opportunity to protect this rare reptile, and the Sonoran desert tortoise is now in a race with extinction,” stated Rosmarino.

WildEarth Guardians and Western Watersheds Project are region-wide conservation organizations with offices throughout the west including Arizona.

View Sonoran desert tortoise profile with range map (PDF)

View Sonoran desert tortoise petiton (PDF)