As part of its push to privatize federal workers, the Bush administration has identified about 70% of full-time jobs in the National Park Service as potential candidates for replacement by private-sector employees.

Interior Secretary Gayle A. Norton, who oversees the Park Service, has earmarked 11,807 of 16,470 full-time positions for possible privatization. They range from maintenance and secretarial jobs to archeologists and biologists.

Interior Department officials stressed, however, that the number of people replaced would not be nearly that high. Moreover, they said that law enforcement personnel, managerial positions and most park rangers would keep their jobs. But some of the people who have come to embody the institution's 86-year-old tradition of public service, as they greet visitors and lead them on nature walks, could be replaced by volunteers.

Critics fear that the outsourcing of federal positions, including the Park Service's entire corps of scientists, could undermine protection of the nation's vast inventory of archeological and paleontological sites within parks and hand over the care of forests, seashores and wildlife to private firms not steeped in the Park Service culture of resource protection.

"This is about respect for professionals. It is about a recognition that people spend a lifetime learning their profession and how to resist pressures -- political or commercial -- in the public interest," said Roger Kennedy, who directed the Park Service during the Clinton administration.

"The public understands that parks are not parking lots -- they are places that require a high degree of professional skill to manage. Not just anyone can do it."

The potential cuts are part of the Bush administration's effort to identify as many as 850,000 federal jobs that could be performed by private-sector employees.

Park Service Director Fran Minella said she wants to maintain uniformed personnel in the parks as a "public face" to visitors. Still, some duties performed by rangers, such as nature walks, could be conducted by volunteers, Park Service officials said.

Interior Department officials say there is little likelihood that all of the jobs identified by Minella will be outsourced.

Deputy Assistant Interior Secretary Scott Cameron said he anticipated that no more than 4% of the current workers would actually lose their jobs.

He said much of the changeover would occur as current employees retire. Cameron estimated that about 20% of the Park Service staff will reach retirement age in the next five years.

The positions identified by Norton will be examined to determine if they can be eliminated or filled more cheaply and efficiently with nongovernmental contract employees.

Park Service employees would be given a chance to argue why they are better equipped to perform their jobs than private sector workers.

Officials say the injection of free market-style competition would bring out the best in employees.

"This is a way to capture the benefits of competition to produce better performance and better value," Cameron said. "Competition makes for a much more exciting Lakers game than if only one team were on the court."

But critics say the responsibility of overseeing the country's more than 380 parks and monuments is too important to entrust to people with little or no preparation for working in the nation's park system.

"The Park Service is not a business enterprise," said Frank Buono, a former assistant superintendent of Joshua Tree National Park and a former manager of Mojave National Preserve. "There is a fundamental ideological binge that the free-enterprise system will heal all wounds and solve all problems. Ask Enron about the efficiency of the unregulated private marketplace."

Public Employees for Environmental Responsibility and others charge that replacing Park Service scientists with "hired hands" would create a conflict of interest and produce a vacuum in parks where esoteric specialists are required.

"What you get is a pliant and controllable science staff," said Jeff Ruch, executive director of the public employees organization. "Our concern is that a biologist who works for the park will be replaced by a private consulting firm, which, in order to get its contract renewed, will tell the park what it wants to hear."

The Interior Department is just one of the federal agencies that have been told to trim jobs.

Randy Erwin, assistant to the president of the National Federation of Federal Employees, said he was "outraged" by the administration's plan to privatize Park Service jobs. "It's a travesty to turn the Park Service into a profit-making center."

But the trend to outsourcing is inexorable, said Fred Smith, president of the Competitive Enterprise Institute, a Washington-based free-market advocacy group.

"The government is way behind the curve," Smith said. "Something as mulch-ridden as the Park Service is long overdue for this. Allow voluntary groups to work in the parks. Let people and groups who care deeply about bats and sea turtles and caves do the work. The private museum system has been using docents for years. It's about time the government caught up."

But those who love the Park Service say being a park ranger is not just any government job. The culture of the service is often likened to that of the Marine Corps, with an almost military-like discipline and devotion to duty. The agency's signature green uniform and Smokey Bear-type hat underscore the image.

James Oliver Horton, a professor of American studies and history at George Washington University, was historical consultant to the Park Service during the Clinton administration. He said the esprit de corps among Park Service employees is unique.

"I observed the kind of camaraderie that comes from people who consider they are doing the Lord's work, preserving what we have come to know as America's treasures," Horton said. "That is, and continues to be, a very important job. To say to those people who have stuck it out, 'Now you are going to be cut,' seems to me a real slap in the face. And a real slap in the face to Americans who want these places preserved."

Established in 1916, the National Park Service grew out of concern for preservation of public lands during a time of widespread plundering of Indian ruins, looting of Civil War battlefields and the degradation of historic buildings and sites.