TUCSON, Ariz.— Cattle grazing has damaged nearly 60% of threatened northern Mexican garter snake critical habitat on public lands in Arizona and New Mexico, according to a report released today by the Center for Biological Diversity.

The aquatic, secretive reptiles, who depend on intact streams, rivers and wet meadows, were historically found in all of Arizona’s major watersheds and some areas of southwestern New Mexico. Despite being protected as threatened under the Endangered Species Act since 2014, its populations have continued to dwindle. One of the primary causes of its decline is habitat destruction caused by illegal cattle grazing.

“By habitually prioritizing commercial livestock over the needs of rare native plants and animals, federal agencies are pushing these beautiful reptiles toward extinction,” said Chris Bugbee, Southwest conservation advocate at the Center. “Agencies have to conserve and restore wild places or these snakes and other increasingly rare species won’t survive. That starts with stopping the cattle industry from destroying protected critical habitat.”

Despite being eliminated from 90% of their former range, the U.S. Fish and Wildlife Service denied Endangered Species Act protection to northern Mexican garter snakes for more than a decade. After years of litigation, the snakes were listed as a threatened species in 2014.

In 2021 the Fish and Wildlife Service designated 20,326 acres of critical habitat in Arizona and New Mexico, a 90% reduction from what the agency originally proposed as sufficient to foster the snakes’ recovery. More than half of these acres are on public lands in Arizona and New Mexico.

Between 2021 and 2023 field biologists from the Center surveyed 69% of those lands. They found moderate to significant damage on 84% of the acres surveyed, which represents 58% of the snake’s critical habitat in public lands grazing allotments in Arizona and New Mexico.

Field biologists documented cows concentrated in streams and riparian areas, often leaving bare, denuded ground, destroyed vegetation and streambanks, and polluted, feces-laden water. Cows were often grazing illegally, in places where grazing is prohibited. Damage to the snake’s critical habitat included parts of Tonto National Forest and the San Pedro Riparian National Conservation Area.

In July, the Center exposed similar damage to western yellow-billed cuckoo critical habitat in Arizona and New Mexico. That report documented destruction from illegal livestock grazing to least 57% of the migratory bird’s critical habitat on public grazing allotments in the two states.

“Given this pattern of neglect, I question whether these federal agencies want struggling species to survive at all,” said Bugbee. “They’ve systematically chosen to put the interests of ranchers over the plants and animals they’re charged with protecting. The biodiversity of the entire Southwest ecosystem is at stake.”

Across the desert Southwest, livestock grazing harms threatened and endangered wildlife and is the primary driver of riparian ecosystem degradation and species imperilment. Removing livestock from riparian areas is critical to curbing the extinction crisis in the Southwest.