Reversing actions of prior administrations that jeopardized opportunities for responsible motorized recreation on public land, President Donald Trump signed two proclamations in December that reduced two monuments in size to more closely align with the law that grants presidents designation authority.

The American Antiquities Act of 1906 limits the area of national monuments to “the smallest area compatible with proper care and management of the objects to be protected.”

Under the new plan, Bears Ears National Monument will be modified to two units named Shash Jáa (Navajo for “Bears Ears”) and Indian Creek, encompassing 228,784 acres of land.

Bears Ears was originally designated by President Barack Obama in 2016 to encompass nearly 1.5 million acres, including a patchwork of federal, state and private land.

Grand Staircase Escalante National Monument will be modified to three units encompassing a little more than 1 million acres. Grand Staircase was originally designated in 1996 by President Bill Clinton.

Viewed through the lens of the Antiquities Act, previous presidents from both parties overstepped their authority under the act and designated much larger swaths of land as monuments. In recent years, the administrative decrees encompassed millions of acres and threatened access to trails and other routes suitable for off-highway recreation.

In many cases, state and local governments opposed the sweeping designations because they were enacted with little or no local input and had a negative impact on the tourism economy.

Trump’s decision followed Interior Secretary Ryan Zinke’s announcement that there would be a review of all presidential monument designations from the Bill Clinton, George W. Bush and Barack Obama administrations.

Presidents have modified the boundaries to remove lands from monuments 18 times in the past. The most significant reduction occurred in 1915 when President Woodrow Wilson halved Mount Olympus National Monument, which is now a national park.