Some might call Elliot Lozano, a 37-year-old biological science technician and weasel specialist, a prime example of why the Trump administration chose to cut 1,000 jobs from the National Park Service.

Others might call him a symbol of the Park Service’s purpose, and a reason employees at Yosemite unfurled an upside-down American flag across the granite face of the landmark monolith El Capitan last week.

Mr. Lozano, who worked at Yosemite National Park, was awarded a $5,000 bonus last year for extraordinary efforts to save one endangered weasel — a baby southern Sierra Nevada fisher found orphaned in the park by his team. He was among roughly 10 Yosemite workers who were told by email on Feb. 14 that they would be fired because their “subject matter knowledge, skills and abilities” were unnecessary. At least 30 other vacancies sit unfilled because of a hiring freeze.

“It does feel like I’m spending my life force trying to solve an important problem,” Mr. Lozano said, still speaking in present tense about his former job.

Lately, there have been few visible signs of the job cuts at Yosemite, a Rhode Island-size national park founded 134 years ago in central California’s Sierra Nevada Mountains that Ansel Adams once called “a glitter of green and golden wonder.” The upside-down flag was taken down. The peak tourist season in the summer is many months away. Climbers are still gathering in the meadows in the thin morning light, peering through binoculars at the specks of their friends up on the big wall as the sun hits the face of El Capitan.