The U.S. Fish and Wildlife Service is designating critical habitat under the Endangered Species Act (ESA) for the northern Mexican gartersnake, which is native to Arizona and New Mexico. Critical habitat can help federal agencies focus their conservation activities in areas that are important to listed species. The northern Mexican gartersnake was listed as threatened in 2014.

In total, 20,326 acres in La Paz, Mohave, Yavapai, Gila, Cochise, Santa Cruz and Pima counties, Arizona, and Grant County, New Mexico, fall within the boundaries of the critical habitat designation.

In 2020 the Service published a revised proposal for the species that included considerable reductions in acreage. This final rule reflects further reductions of approximately 7,458 acres from the revised proposal. Most of the reduction in acreage resulted from exclusion of lands from critical habitat based on conservation plans that address special management needs of habitat for the species.

Northern Mexican gartersnake populations have declined primarily from interactions with predatory, non-native species such as bullfrogs, crayfish and warmwater sportfish. These compete with and prey upon both the snakes themselves and their native prey species, causing both gartersnake mortality and starvation within populations. Drought that diminishes surface water or degrades streamside vegetation is also a significant threat, especially where it occurs in the presence of non-native species.

This critical habitat designation identifies areas that are particularly important to the conservation of this gartersnake, where actions of federal agencies or activities that require federal permit or funding must be analyzed to prevent the incidental adverse modification of their habitat. It does not mean no development can occur in these areas, only that federal agencies must consult with the Service if they are conducting, funding or permitting activities that may affect the species.

Native aquatic ecosystems contain some of the highest levels of biodiversity in the Southwest. Their protection and conservation is an American value and critical to many species of aquatic insects, fish, amphibians, reptiles, waterfowl and other wildlife, as well as humans. It is the Service’s responsibility to protect the northern Mexican gartersnake, work with partners to manage threats to the species and encourage healthy aquatic communities.

America’s fish, wildlife and plant resources belong to everyone, and ensuring the health of imperiled species is a shared responsibility. The Service is actively engaged with conservation partners and the public in the search for improved and innovative ways to conserve and recover imperiled species. To learn more about the Endangered Species program visit our website https://www.fws.gov/southwest/es/arizona/Docs_Species.htm.