One man pleaded guilty and another pleaded not guilty in federal court on Monday to misdemeanor charges relating to their blocking access to a buffalo quarantine facility in Yellowstone National Park on Friday.

Joshua Rivera of Clifton, Colo., pleaded guilty to trespassing, tampering, vandalism -- obstruction of roadway; interfere with an agency function; and a closure violation, during his initial appearance and arraignment before U.S. Magistrate Judge Mark Carman at the Yellowstone Justice Center in Mammoth.

The federal prosecutor dismissed the closure violation charge as part of the plea, according to the minutes of the hearing.

Carman sentenced Rivera to three years of unsupervised probation on the first two counts, and ordered him to pay $1,936 in restitution joint and several -- in which each defendant is responsible for making payment -- with co-defendant Mark Wolf for obstructing the roadway.

Carman also banned Rivera from entering Yellowstone National Park for three years.

Wolf of McCullum Lake, Ill., pleaded not guilty to all three counts.

Carman set an unsecured bond for him at $2,500, and banned him from the park during the period of bond except for future court hearings. Wolf's next court date is set for April 4.

They are members of the Wild Buffalo Defense organization, according to its Facebook page.

The protesters, identified as "Wolf" and "Coyote," blocked the gate with three 55 gallon drums filled with concrete, locking their arms inside the barrels. The three 1,000-pound drums prevented livestock trucks from taking the wild buffalo to slaughter, according to Wild Buffalo Defense.

The barrels were painted with the phrases, "Protect the Sacred" and "Honor the Treaties," highlighting how buffalo are sacred creatures to the Plains Indians, according to Wild Buffalo Defense.

The organization also took responsibility for the three people who were arrested two weeks in the same area. They were sentenced in federal court earlier last week to time served in jail, fines, and a five-year ban from entering the park.

On its Facebook page, the group describes itself as, "a collective of indigenous and non-native organizers dedicated to seeing wild buffalo roam free on the plains and to protecting the treaty rights of native people to harvest buffalo. We use direct action physically stop Yellowstone National Park's continued slaughter of the last wild buffalo and raise awareness about the issue."