For readers unfamiliar with tortoise species, there are currently two recognized sub-populations of desert tortoise in the United States, the Sonoran and the Mojave. A third species, the Sinaloan, lives in eastern Sonora, Mexico and into northern Sinaloa, Mexico. The Mojave population is found in the Mojave Desert in southwestern Utah, southern Nevada, and southeastern California. The Sonoran Desert tortoise’s habitat includes nearly 75% of Arizona–significantly the western, southwestern, and central parts of the state south and east of the Colorado River In 1990, the entire Mojave population was listed as threatened and in 1994, 6.45 million acres were designated as critical habitat for the Mojave population in California, Nevada, Utah, and Arizona. As one can imagine, ranching in these regions was severely impacted since grazing was determined as one of several possible factors contributing to the tortoise’s decline in population.
In 2008, a petition to list the Sonoran Desert tortoise under the Endangered Species Act was put forth. In 2010, the FWS determined the tortoise warranted protection, however there were higher priority species to be listed at the time and it was decided the Sonoran Desert tortoise would be reviewed annually. While grazing was not considered a contributing factor to the threat of the species, producers and Districts in Arizona saw what happened with the Mojave Desert tortoise formed the Ranching and Sonoran Desert Tortoise Working Group in 2011 to address any potential grazing effects.
The Working Group–made up of resource specialists from state and federal land and resource management agencies and, most importantly, included four ranchers: Bill Dunn, Stefanie Smallhouse, Walt Meyer, and Francie Meyer—collaborated to preempt grazing being identified as a threat and to keep the species off the list by developing the Best Management Practices for Ranching in Sonoran Desert Tortoise (Gopherus morafkai) Habitat in Arizona Guidebook. The guidebook is just that, a guide meant to assist ranchers in implementing conservation measures during day-to-day operations to reduce and/or eliminate potential grazing effects on the Sonoran Desert tortoise. It is also intended to help guide officials who are unfamiliar with ranching to make better decisions regarding livestock and tortoise management.
In 2015, the FWS determined that the Sonoran Desert tortoise was not facing the threat of extinction and removed from the candidate list. However, in July 2020, WildEarth Guardians and Western Watersheds Project challenged the 2015 decision and the FWS reached an agreement with them to place the SDT back on the endangered species candidate list, re-evaluate its status and reach a decision in 18 months. That decision is slated to be made by February of 2022.