|Glacier Point Infrared - Yosemite National Park, California|
Unfortunately for you and I and pretty much everyone who might want to apply is that "well qualified candidates" must have at least one year experience as a federal government photographer (GS-10 or higher) and be proficient with large format black-and-white film. I gaurantee that few people have those credentials. You might have tons of experience with large format cameras and be a great photographer, but if you have never had a federal government photography job that was at least GS-10, you don't stand much of a chance at landing this job.
With these kind of things the Department of the Interior has already selected the photographer they want. There have been behind-closed-door conversations with the photographer. They've told this person to look out for the announcement and apply when it comes out (the short window of the opening is a big clue). Just as long as that person applies the job is his or hers. This person probably works for the Department of Defense or the executive branch, just guessing.
It's not a fair system. It's rigged. It's "good ol' boy" for sure. But that's the way it works, sadly. But don't despair--if you want to photograph the National Parks, go ahead and do so. Start with the ones closest to you. Don't worry that no one is paying you--if your photographs are good enough, eventually you'll get compensated for your work. Make it a priority to travel to whatever beautiful locations are near you and capture those places as best as you can.