For 13 years, rock climbers have been prohibited from sinking their hands and feet into Williamson Rock after a tiny endangered frog with yellow legs turned the crag from Southern California’s most popular rock-climbing spot into a no-climb zone.

Soon, they may get that chance again thanks to a frog rehab effort — and a plan that accommodates both climber and amphibian.

Located in the Pleasant Ridge section of the San Gabriel Mountains National Monument a half-hour’s drive from Wrightwood, the yellow-colored outcropping squatting over Angeles Crest Highway was once covered with hundreds of rock climbers each day, testing their mettle on the granite bulge 7,000 feet above sea level.

But a temporary closure was followed by years of no access. Adrenaline junkies have waited patiently for the population of the mountain yellow-legged frog at the rock’s base in Little Rock Creek to rebound.

After being squished, their eggs crushed by hikers and climbers and tadpoles taken from their creek home, the number of frogs dwindled to about 100. They were listed as an endangered species.

Lawsuits by the Center For Biological Diversity forced the U.S. Forest Service to close the hiking area, the climbing rock and a portion of the trails near the creek — including the famous Pacific Crest Trail, the subject of the 2014 movie “Wild,” starring Reese Witherspoon.

In the past 12 years, biologists from the San Diego Zoo Global, the Los Angeles Zoo and the U.S. Fish and Wildlife Service have bred the mountain yellow-legged frog (Rana muscosa) in captivity and released 3,800 tadpoles and sub-adults into creeks and streams in the San Gabriel and San Bernardino mountains, with the latest release on July 25.

Last week the USFS released a draft Environmental Impact Statement that lays out options for protecting the frog’s habitat — including areas around the rock — while allowing climbing and hiking for the first time since 2005.

The movement toward a resolution — that once began in 2014 but stalled for lack of funding — is something welcomed by Friends of Williamson Rock and Allied Climbers of San Diego, who have advocated a balanced plan.

Balancing act

Matthew Bokach, manager of the 346,000-acre national monument carved out of the Angeles National Forest, said the successful return of the rare frogs to Little Rock Creek, combined with a proposal to reopen the area, balances the dual mission of the monument as set by President Barack Obama during its dedication Oct. 10, 2014.

“The Williamson Rock project really captures these two charges: public access and recreational opportunities while protecting the sensitive animal population that is present,” Bokach said during an interview Tuesday.

The EIS essentially lays out four proposals with the goal of protecting the frogs and peregrine falcons nesting on the granite rock’s highest outcropping, while allowing hiking and rock climbing with restrictions. Alternative No. 1 would open up recreation year-round to all; Alternative No. 2 would keep the existing bans and measures in place.

Bridge over creek, limited climbing

Alternative No. 3, the action plan proposed by the USFS, would allow climbers back on the rock only between Aug. 1 and Nov. 15 — a short window created to avoid disturbing nesting peregrine falcons — and only via paid permits, Bokach said.

Also, hikers on the Pacific Crest Trail would avoid the young frogs in Little Rock Creek by taking a new pedestrian/equestrian bridge over the creek.

Some features of the action plan in Alternative 3 include:

• Keeping the number of climbers to 90 per day at first, with the possibility of 120 if the peregrine falcon chicks are fledgling and no longer in peril.

• Building a permanent bridge that would reopen the segment of the PCT that is now closed while keeping hikers out of the creek and away from frogs, tadpoles and eggs.This would prevent trampling of eggs and frogs and taking of tadpoles. Also, hikers’ shoes could no longer spread chytrid fungus, which gets under the skin of the frogs and can be fatal.

• The bridge would close a gap in the PCT that caused hikers to walk along the curving Angeles Crest Highway.

“That is not ideal because there is no real shoulder and it is not safe,” Bokach said.

• Hiring bird monitors to keep climbers away from the peregrine rock nests. The peregrine falcon is the fastest animal in world and can fly 260 miles per hour to catch another bird in flight as prey. The species, along with bald eagles, brown pelicans and osprey, were nearly extinct due to the effects of the pesticide DDT, which was banned in North America in 1972. The peregrine falcon was removed from the federal endangered species list in 1999.

Alternative 4 proposes a 2.5-mile re-routing of the PCT away from Williamson Rock and Little Rock Creek.

Balancing people and animals

Opening up the rock again to climbers could damage the recovery of the birds and the frogs and “impacts could have a substantial adverse effect,” according to the document.

In 2016, biologists counted 610 first-year and 148 second-year tadpoles in Little Rock Creek.

However, in May 2017, biologists saw climbers on the main face, and evidence of illegal actions including litter, smoke staining and charcoal from campfires, the report stated. Any plan would be a balancing act, Bokach said.

“This is a special area, L.A.’s backyard; we have to try to make it more accessible to an urban population,” he said.

How to comment

• Attend the following public meetings:

— Thursday, Aug. 9, 7 p.m. to 9 p.m., Angeles National Forest Work Center, 33708 Crown Valley Road, Acton, CA 93510

— Saturday, Aug. 11, 1 p.m. to 3 p.m., Angeles Training and Conference Center, 701 N. Santa Anita Ave., Arcadia, CA 91006

• Go to the following website for more information: https://www.fs.usda.gov/project/?project=43405 and submit a comment via the link on the page.

• Mail correspondence to: 701 N. Santa Anita Ave., Arcadia, CA 91006.