Horse packers and others can weigh in today on how Yellowstone National Park will regulate their kind in the backcountry of the world’s first national park.

Park officials will be in Jackson to gather opinions on the topic at 6 p.m. at the Lexington at 285 N. Cache. The session is one of five the National Park Service has scheduled as it seeks to analyze commercial stock outfitter use in the 2.2 million-acre reserve.

Commercial stock day use has increased by about 50 percent in the past 15 years, officials said in an email to horse users and others.

Yellowstone intends to analyze the situation through an environmental assessment that would guide managers as they issue permits or promote or curtail use.

The goal is to come up with revisions to today’s standards by the 2014 summer season.

“When we acknowledge we’ve seen an increase in activity, it’s time for us to look at it — just plain and simple,” park spokes-man Al Nash said Monday. “Overall, our staff believes we’ve seen an increase in backcountry stock use during the recent years.”

Backcountry use by commercial stock outfitters has averaged 5,500 nights annually over the past six years, the park said in its call to meetings. That’s about 14 percent of the 40,460 backcountry nights last year. Total backcountry use is only 1 percent of annual recreation visits.

“We figure it’s time for us to look at that level of activity and see how that may be impacting the environment,” Nash said.

He said he hasn’t heard any reports of horses and riders overwhelming trails.

Tonight’s meeting launches the “scoping” phase of the assessment, which will be written under the umbrella of the National Environmental Policy Act. Federal officials gather ideas from interested parties to help define the scope of the review.

“We’re still at the blank-sheet-of-paper time frame,” Nash said. “If anyone has an opinion, this is the perfect time to share.”

Today, Yellowstone has 45 concession contracts for guided saddle and pack stock tours.

Among the actions that could result from the review are limits to day use, resource monitoring, trail management and stock waste management, the park meeting announcement said. At issue is potential harm to resources, including everything from soils to water quality to wildlife.

The environmental study will provide a “decision-making framework” that considers a range of alternatives to address commercial stock outfitters, evaluate issues and potential effects, identify ways to reduce impacts, and prescribe for conservation over coming decades.

The park will consider comments received by March 31 at Commercial Stock Outfitter EA, P.O. Box 168, Yellowstone National Park, WY 82190.