Since 1987 population has declined by 51%-Western Watersheds Project and WildEarth Guardians petition for ESA status and the designation of critical habitat
News story in the Arizona Daily Star. Endangered status sought for Sonoran Desert tortoise. By Tony Davis
Here is the news release from the petitioners-
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Federal Protection Sought for Rapidly Declining Sonoran Desert Tortoises
Arizona, 10/09/08: Today, Western Watersheds Project and WildEarth Guardians filed a petition requesting that the U.S. Fish and Wildlife Service (USFWS) 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 found that monitored 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.
“In 1990, when the Mojave population of desert tortoises was listed, the USFWS 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
“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.
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
If listed under the Endangered Species Act, Sonoran desert tortoises would be protected from
“take” (including killing and harassment) of individual tortoises and the USFWS would have to
develop a recovery plan to map out the steps that must be taken to reverse the declines. The
USFWS 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.