TUCSON, Ariz.— As part of a landmark 2011 agreement with the Center for Biological Diversity, the U.S. Fish and Wildlife Service finalized Endangered Species Act protections today for the Southwest’s narrow-headed garter snake and northern Mexican garter snake. Threatened by exotic species and the loss and degradation of river and streamside habitats, these nonvenomous, 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, a Center attorney who focuses on the protection of imperiled amphibians and reptiles. “Protecting them, and the shrinking waters of the Southwest, will benefit every other animal that depends on these river systems.”
The decline of Mexican and narrow-headed garter snakes has been caused by the destruction of their streamside habitats through livestock grazing, water withdrawal, and agricultural and urban sprawl, as well as by the introduction and spread of nonnative species like 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 at risk of extirpation. 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 or may be gone.
“The decline of these snakes is typical of the catastrophic loss of aquatic animals across the Southwest,” said Adkins Giese. “These snakes depend on native fish and amphibians for their food, and the widespread loss of the snakes and their prey reflects a severe collapse of the food web in southwestern rivers and streams.”
The Center petitioned for the Mexican garter snake in 2003. After several lawsuits, the snake 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 the group’s landmark 2011 settlement with the Fish and Wildlife Service, 120 species have already gained Endangered Species Act protection, including the two snakes, and another 23 have been proposed for protection.