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 petition provides substantial scientific data showing that monitored Sonoran desert tortoise populations have declined by 51% since 1987 throughout their range in Arizona.

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. 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 seen in Sonoran Desert tortoise populations since then now require swift action by the federal government.

The petition catalogs 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. The combined assault of threats such as disease, cattle grazing, and development are pushing Sonoran desert tortoises closer and closer to extinction.

Click the links to read the Listing Petition and WWP Press Release