Two Rare Southwest Snakes Proposed for Endangered Species Act Protection

As part of a landmark agreement with the Center for Biological Diversity, the U.S. Fish and Wildlife Service today proposed Endangered Species Act protections for the Southwest's narrow-headed garter snake and northern Mexican garter snake. In New Mexico and Arizona, the agency also proposed to protect more than 420,000 acres of critical habitat for the Mexican garter snake and more than 210,000 acres for the narrow-headed garter snake. Threatened by nonnative species and the loss and degradation of riparian habitats, these non-venomous, aquatic snakes have undergone massive declines in recent decades.

"These two southwestern snakes have been in trouble for years, so I'm glad they're finally getting the protection they desperately need to survive," said Collette Adkins Giese, an attorney at the Center who focuses on the protection of imperiled amphibians and reptiles. "Protecting these snakes and their beleaguered habitat in the Southwest will benefit every other animal that depends on these river systems."

The main culprits in the decline of the Mexican and narrow-headed garter snakes are the destruction of their streamside habitats due to livestock grazing, water withdrawal, and agricultural and urban sprawl, as well as the introduction and spread of nonnative species, such as sunfish, bass and crayfish. The snakes have undergone dramatic range-wide declines in the United States and are now almost entirely limited to small, isolated populations that are at risk of extirpation. Indeed, the Fish and Wildlife Service found that "83 percent of the northern Mexican garter snake's populations in the United States and 76 percent of the narrow-headed garter snake's populations occur at low densities and are likely not viable."

"The decline of these snakes is symptomatic of widespread declines in the aquatic fauna across the Southwest," said Adkins Giese. "These snakes depend on native fish and amphibians as prey, and the widespread loss of these snakes and their prey reflects a severe collapse of the food web in Southwest rivers and streams."

The Center petitioned for the Mexican garter snake in 2003. After several lawsuits, it was designated a candidate for Endangered Species Act protection in 2008. In 2011 the Center submitted a status report documenting the need for Endangered Species Act protection for the narrow-headed garter snake. Under a historic 2011 settlement agreement with the Center that requires the Fish and Wildlife Service to issue protection decisions for 757 species around the country, the agency must make a final decision about protection for the snakes in fiscal year 2014.