Desert Tortoises Have Lived In The Deserts Of California

Desert tortoises have lived in the deserts of California, Arizona, Nevada and Utah since the Pleistocene. In the early years of the 20th century, they still thrived within the Southwest’s arid landscapes: As many as 1,000 tortoises per square mile once inhabited the Mojave. But by the end of the century, this population of the desert tortoise was listed as a threatened species under the Endangered Species Act. Livestock grazing and urban development, along with the ever-increasing use of off-road vehicles, continue to degrade the tortoise’s vanishing habitat, while Army translocation projects threaten to devastate the Mojave population.

Thanks to a lawsuit filed by the Center and Desert Survivors, in 2008 Fort Irwin officials suspended a disastrous desert tortoise translocation project that killed hundreds of the animals as part of “mitigation” for expanding the military base into tortoise habitat. The Army and Bureau of Land Management proposed a new translocation project in 2009 — but after tens of thousands of letters from Center supporters, the Bureau halted the project.

We’ve been working for the Mojave desert tortoise since 1997. Challenging the Bureau of Land Management’s grazing practices on arid public lands, we’ve helped protect millions of acres of fragile tortoise habitat. We’ve actively sought to limit off-road vehicle use throughout the desert tortoise’s range, including appealing the opening of two illegal off-road vehicle routes in Kern County, California. In 2000, we made significant gains for the desert tortoise when, as a result of our legal efforts, the Bureau permanently cancelled all livestock grazing on 276,125 acres of the Granite Mountains Grazing Allotment. In 2002, we and allies won another landmark settlement in which 1.9 million acres of the California Desert Conservation Area were protected against livestock grazing and 18,000 acres of tortoise habitat were closed to off-road vehicle access. More recently, we called on the U.S. inspector general to investigate the role of political meddling in the tortoise’s badly revised draft recovery plan and went to court to prevent a California mine expansion from affecting 178 acres of tortoise habitat.

In 2011, a study showed that desert tortoises in California and the Southwest are two different species instead of one. Scientists discovered that desert tortoises living north and west of the Colorado River (the Mojave population now called Agassiz's desert tortoises, or Gopherus agassizii) are officially a different species from tortoises in Arizona and Mexico (previously called "the Sonoran population of desert tortoises" and newly dubbed Morafka's desert tortoises, or Gopherus morafkai). The new study means that each desert tortoise species is even rarer than previously thought.