A possible solution to an annual, winter problem around Yellowstone National Park may have been resolved through a tentative agreement to allow up to 100 bison to migrate along a private corridor between the northern boundary of the park and the Gallatin National Forest, reports the Wildlife Management Institute.

Yellowstone bison are known to carry brucellosis, a bacterium that can cause abortion of fetuses in livestock populations. Park officials estimate that nearly half of the 3,500 bison that live in the park have tested positive for exposure to the bacteria. In recent years, due to fears of contamination to domestic cattle and the loss of Montana's "brucellosis-free status," and based on a 2000 management plan, most bison that have left the park to move to winter range, have been hazed back. Others have been rounded up for testing for the disease.

The management plan has been controversial because of a lack of evidence that bison can transmit brucellosis to cattle. In addition, elk populations throughout the Greater Yellowstone Ecosystem have a high incidence of brucellosis, which many experts connect to the practice of winter-feeding areas.

The tentative agreement would have state and federal agencies purchase grazing rights from the Royal Teton Ranch, removing approximately 250 cattle from the ranch and allowing bison access to more than 2,000 acres of winter range within the Gallatin. The deal also would restrict building on ranch property.

Negotiated in large part between the Montana Fish, Wildlife and Parks Department and the Church Universal and Triumphant, and the owners of the Royal Teton Ranch, the agreement will alleviate some of the pressure on bison that leave the Park. Since 1998, the federal government has spent nearly $13 million to acquire conservation easements on the ranch, but an agreement on grazing rights has been elusive.

In 2005, after Montana Governor Brian Schweitzer entered office, discussions began in earnest to identify a "creative fix" to the issue. Under the tentative agreement, the state of Montana will purchase some of the grazing rights, and Congress and conservation organizations will provide the remaining funds. However, the House Appropriations Committee rejected an Interior and Environment Appropriations bill amendment to provide $1.5 million towards the deal. Full funding for the lease agreement likely will not be arranged before the winter of 2008-09.