Wyoming Game & Fish identifies Sublette pronghorn corridor; designation not yet final

Wyoming Game and Fish told the Select Federal Natural Resource Management Committee that a multi-year study of pronghorn movements supports identifying a migration corridor for the Sublette herd, but the corridor has not been formally designated.

Doug Brimeier, deputy chief of wildlife for the Wyoming Game and Fish Department, presented maps and a scientific approach that used 20 years of radio-collar data and collaboration with the University of Wyoming. The department extracted 415 individual migratory pronghorn and 800 documented migration sequences, then applied a line-buffer method with a 300‑meter buffer to create high-, medium- and low-use corridor polygons and green stopover polygons where animals spend the bulk of their time. Brimeier said the approach follows recent peer-reviewed guidance and helps identify areas where animals rely on seasonal connectivity.

"For the department's purposes, identifying the corridor is all about using the best science to inform our decisions," Brimeier said.

Brimeier and colleagues emphasized that "identification" is an intermediate step. The Game and Fish Commission voted in March to identify the corridor and directed the agency to complete a biological risk and opportunity assessment. That assessment will be followed by additional public input, a commission recommendation and, if the commission supports designation, a governor-convened local working group laid out by the governor's executive order on migration corridors. Sarah Dorenzo, policy adviser to Governor Gordon, described the governor's process: if the commission recommends designation, the governor would convene an area working group — including local county commissioners and representatives of hunting, conservation, motorized recreation, agriculture and industry — to review the science, socioeconomic impacts and mitigation options before the governor decides whether to designate.

BLM officials told the committee they do not themselves designate migration corridors but said the agency will work with Game and Fish and follow established cooperating-agency processes when projects in the corridor are reviewed. "We support Wyoming Game and Fish's effort to identify the corridor," Andrew Archuleta, BLM state director, told the committee, adding that BLM will recommend best management practices at the project level and incorporate state inputs during NEPA review.

Committee members questioned how infrastructure barriers such as Interstate 80 and rail lines affect migrations. Brimeier said I-80 is a barrier in places and that the department is studying potential crossing and mitigation locations, while noting that railways have contributed to mortalities in some areas.

Why it matters: Pronghorn migrations can span long distances and depend on intact movement corridors and stopover areas. Identification and potential designation would not change private landowner rights or existing permits, Brimeier said, but could affect siting, timing and mitigation for new state or federal projects in stopover and high-use areas.

Next steps: Game and Fish will complete a biological risk and opportunity assessment and return to the commission within roughly a year. If the commission recommends designation, the governor's office will lead a public, local-working-group process before any formal designation is made.