A southwest Montana ranch may soon be home to some wild horses.

Dean Bolstad, deputy chief of the National Wild Horse and Burro Program, approved an environmental assessment of a 10-year program to place excess wild horses at the Rice-Spanish Q Ranch near Ennis.

The National Wild Horse and Burro Program is a division of the U.S. Bureau of Land Management.

Barring any court action, the Ennis plan will be effective Dec. 10. Bolstad said the first horses could arrive shortly after Dec. 10.

The plan would gradually move up to 800 wild geldings onto the ranch, which will be known as the Ennis Long-Term Holding Pasture. Around 100 horses will be delivered every other week and held in pens for two weeks to acclimate them to their surroundings.

The BLM creates long-term holding pastures to provide a more natural environment for more than 14,000 wild horses penned in cramped short-term facilities. The horses can languish in such facilities for months after being removed from herds that have grown too large for their management areas.

Bolstad said the horses could arrive in Ennis from any of the short-term facilities in the western U.S. He said the sexes are usually separated for ease of management.

The Rice-Spanish Q Ranch has close to 24 square miles of private land and land leased from the state where the ranch has managed up to 2,000 head of cattle.

BLM employees will monitor the vegetation and condition of the land during the contract. If conditions don’t deteriorate after the first year, managers could bring in additional horses up to a limit of 1,150.

Based upon the assessment findings, wild horse managers have little reason to expect the conditions would deteriorate.

The condition of the wetlands and riparian areas near the seven creeks that thread through the property may even improve.

Horses use streams less frequently than cattle and prefer to move to upland areas to graze. So riparian damage could be less than it has been with cattle.

Water supplies have proven sufficient to support greater numbers of cattle.

To limit damage caused by grazing, the horses will move between upland and lower pastures during the year and will spend one year on the east side and the next year on the west side of the property.

The horses could compete with elk for forage, but pasture rotation would leave areas untouched for elk.

Wildlife advocates didn’t want smooth-wire fences to be higher than 46 inches tall but fences need to be 2 inches taller to hold horses. If wildlife becomes entangled, parts of the fence may be modified in the future.

BLM managers point out that if they didn’t lease the property, the ranch owners may subdivide the property or bring in more cattle, neither of which helps wildlife.

The National Wild Horse and Burro Program has 179 herd management areas in 10 states. Montana has one management area in the Pryor Mountains south of Billings.

The program also oversees more than 47,000 horses being kept in short- and long-term holding facilities. That number continues to grow as adoption activity has dropped and the agency needs other options.

Laura Lundquist can be reached at 582-2638 or llundquist@dailychronicle.com. Follow her on Twitter at @llundquist.