Trump administration guidelines aimed at dramatically shrinking the size of federal government could diminish services across the National Park System "like no other time since WWII," according to a National Park Service veteran who spent decades with the agency.

While the National Park Service, and other federal agencies, are in a state of turmoil under the administration's push to drastically shrink the size of government, the agency has no idea how many vacant superintendent positions exist across the National Park System.

President Trump's choice of a former director of the Wyoming Game and Fish Department to head the U.S. Fish and Wildlife Service is generating controversy, with the National Wildlife Federation calling Brian Nesvik a solid choice while the Center For Biological Diversity views him as a threat to the Endangered Species Act. The Endangered Species Coalition called the nomination a declaration of "war on wildlife."

The National Park Service has been given permission to hire "certain positions" previously blocked by President Trump's freeze on government hiring, though the agency didn't say which positions it can fill.