Mormons planning to re-enact treks on national historic trails in central Wyoming will have to do so without the use of support vehicles and only Mondays through Fridays, according to a decision signed Monday.

Permits will be available for a total of 7,500 people annually in groups of 26 or more - far fewer than the 12,000 handcart trekkers who have used the area in recent years.

Jack Kelly, Bureau of Land Management Lander field office manager, said the changes reflect the agency's need to minimize impacts to the area that have been growing with the boom in use.

"We knew we were experiencing too much impact at 12,000. We'd seen that for a couple of years running," Kelly said. "We knew that was having too much impact, particularly relating to support vehicles, and also restrooms. So the people that did the analysis were trying to do what they felt was a sustainable carrying capacity - what can we do to manage properly, to not hurt the long-term historic character of the trails."

The plan to manage 26 miles of BLM lands between the Church of Jesus Christ of Latter-day Saints' holdings at the Sixth Crossing of the Sweetwater River and Rock Creek Hollow near South Pass has been at issue for several years, after scores of trekkers have come to the area to re-enact westward pilgrimages of ancestors. The area is also home to a segment of the Oregon Trail.

Permits for a total of 7,500 people in groups reflects the BLM's proposed plan drafted last May. Of those, 5,000 spaces are earmarked for church users.

The remaining 2,500 spaces are available to church users on a first-come, first-served basis through the BLM. If there is more demand, the BLM will implement a lottery system, the decision said.

People in groups of 26 or more, or with three or more vehicles, are required to have permits. A $4 fee per person per day will be charged.

Eldean Holliday, director of the Mormon Handcart Historic Sites in Wyoming, said the new regulations may cause some glitches.

"The straw that breaks the camel's back is getting very close," he said. "It makes it quite difficult to utilize the trail as we've been accustomed to doing."

He said some groups have canceled because of the $4 fee. But the Monday through Friday regulation and the number of permits should be workable, he said.

"It does require some reassigning and some redirecting of groups that wanted to come, to other places," Holliday said. He said if people above the church's allocated 5,000 spots want to come, they can try to get permits through the BLM for the other 2,500 spaces.

The decision also cuts the group size in half to 200 people per group. Some people complained that 400 people in one group was too many, and people waiting for the group to pass had to wait a long time.

Kelly said this cut also reflects a need to reduce disturbance to wildlife.

Use of support vehicles for all large groups is eliminated, though small groups - such as families - can continue driving on the trails where allowed.

"It's different when you get a big permitting activity and the intensity of use that this permitting group has," Kelly said. "It's too much impact. It's one thing to have a few people driving on the trail. It's a whole other thing to have support vehicles every day throughout the summer. That's one of the biggest differences we saw over the years when we didn't have this intensive activity. The most impact we're seeing is from support vehicles. It's one thing we knew we had to get a handle on."

Starting next year, the season of use will shift from the current June 15-Sept. 1 period to July 1-Sept. 15. The BLM elected to phase that in because of previous plans for trail excursions this year. The change will be made because of wildlife breeding periods and spring runoff conditions, Kelly said.

A two-mile segment of the Rocky Ridge trail will be closed entirely to motorized vehicles.

BLM is hiring a person who will do ground monitoring and supervision of the area this summer to watch the impacts of the decision.

Monday's decision on handcart trekkers and overall use does not affect activity at Martin's Cove in Natrona County.

What the BLM decided

Highlights of the BLM decision regarding Mormon Trail re-enactors:

* Church use Mondays through Fridays at 4 p.m.

* Season of use July 1 to Sept. 15 (starting 2006).

* No support vehicles for permitted groups of more than 26 people.

* $4 per person per day fee.

* Groups of no more than 200 people.

Small changes in routes will also be implemented by the BLM:

* The two-day trek will use the national historic trail and other existing two-tracks to the improved Hudson-Atlantic City Road. That road will be used for about four miles from Sixth Crossing of the Sweetwater to a staging area until a new alternative route can be found north of the Hudson-Atlantic City Road on existing two-tracks. That route will continue over Rocky Ridge to Rock Creek Hollow.

* The one-day trek route will use the existing routes.

* Half-day trekkers will go from the existing two-track from the Hudson-Atlantic City Road staging area to Lower Monument, then follow historic trails up to Rocky Ridge. On the way back, there will be a loop route along the historic trails west to the Lewiston Lakes Road, then returning to the Sage Creek Campground. This route goes through a small section of private land, for which the trekkers will have to receive permission. If permission is denied, trekkers will have to go through the historic trails exclusively back to Sage Creek.

Prospect for appeals:

* These decisions may be appealed to the Interior Board of Land Appeals within 30 days. An appellant has the burden of showing that the decisions appealed are in error.

* Appeals may be sent to the Lander Field Office, P.O. Box 589, Lander, 82520.

* For a copy of the decision, visit http://www.wy.blm.gov/newsreleases/2005/03/28lfo-oregontrail.htm.

Environmental reporter Whitney Royster can be reached at (307) 734-0260 or at royster@trib.com.