Last Monday morning, 23 of the 277 bison brought in during the annual roundup at Wind Cave National Park were loaded in a semi-trailer and shipped to a Nature Conservancy-managed property in Mexico. The translocation project will establish a satellite herd on grasslands in Chihuahua that are part of the species’ historic range.

Back in 1911, the American Bison Society selected Wind Cave National Park as one of the first areas where free-roaming bison herds would be re-established in their historic range. The stocking program, part of a campaign to rescue bison from the brink of extinction and restore their numbers to healthy levels, was a rip-snorting success. Today Wind Cave’s bison herd numbers about 500 and is one of only two genetically pure (no cattle DNA) wild bison herds in the United States. And unlike the genetically pure herd at Yellowstone National Park, Wind Cave bison don’t carry brucellosis, a disease that poses a potentially serious threat to the cattle industry. Wind Cave is, in brief, the world’s only source of genetically pure, brucellosis-free wild bison.

Lots of Wind Cave bison end up being translocated. That’s because the National Park Service, acting in accordance with the Department of the Interior’s Bison Conservation Initiative and the draft recommendations of the Bison Genetics Workshop, officially promotes the establishment of satellite bison herds with the genetic characteristics of the Wind Cave population. The Wind Cave National Park Bison Management Plan (December 2006) gives Wind Cave's superintendent discretionary authority to distribute surplus bison to government agencies, public zoos, universities, tribes, and other entities.

Distributions from the annual bison roundup completed at Wind Cave last month underscore the large scale and complex, geographically diverse nature of the translocation efforts to date. Most of the 96 bison shipped out of the park this year went to fill tribal requests. Wind Cave shipped bison to the Fort Peck Tribes in Montana, the Spirit Lake Tribe in North Dakota, and the Standing Rock Sioux Tribe in the Dakotas. Wind Cave also shipped bison to several properties managed or co-managed by The Nature Conservancy, an NGO that has been working with Wind Cave for several years to establish satellite herds in appropriate locations. This year, TNC arranged for bison to be shipped to Broken Kettle Grasslands in Iowa, Tallgrass Prairie National Preserve in Kansas, and Rancho El Uno in Mexico.

Yes, Mexico. Although it may come as a surprise to many, there is nothing to prevent the Wind Cave superintendent from authorizing the translocation of bison to Mexico if establishing a satellite herd there makes good sense. And in this case, it certainly does. If all goes as planned, this translocation will be recognized as one of the more outstanding examples of international wildlife management collaboration in recent decades.

In the northern Janos Valley less than 100 miles south of Hidalgo County, New Mexico, there is a 46,000-acre ranch in the Mexican state of Chihuahua that is being managed by The Nature Conservancy-Mexico. Dubbed Rancho El Uno, this big swath of the Janos grasslands was recently designated El Uno Ecological Reserve by the Mexican government. The new preserve is part of a 1,350,000-acre grassland region soon to be designated a Biosphere Reserve in recognition of its continental-scale ecological value.

The El Uno Ecological Reserve was once grazed by bison herds. Now TNC-Mexico, the Mexican government, and a consortium of Mexican environmental advocates are determined that it will be again.

A salient objective of the Bison Recovery Effort is to restock El Uno Ecological Reserve with genetically pure bison. Towards this end, a request for bison was submitted to Wind Cave and steps were taken to insure there would be no contact with the “transboundary herd.” (Located about 50 miles to the north, the transboundary herd, which is known to have some cattle gene retrogression, moves back and forth between Chihuahua and New Mexico.)

Now that twenty young cows and three young bulls have been shipped from Wind Cave to the El Uno Ecological Reserve, the Mexican bison recovery program is ready to shift into high gear. Eventually, a bison herd will be established in each of the four Mexican states that once had bison.

Bison are not the only beneficiaries of this restocking program. The entire mixed grassland ecosystem benefits from the presence of bison, a keystone species whose participation in the cycling of matter and the flow of energy improves habitat for a wide range of plants and animals, including not only common animals like the black-tailed prairie dog, but also rare and threatened species such as the burrowing owl and the black-footed ferret (recently translocated from the U.S.).