Mr. Holm echoed the concerns but was optimistic about the land’s ability to rebound. “Nature’s durable,” he said. What worries him more is the unknown archaeological damage. The occupiers handled Indian artifacts stored at the refuge and spoke repeatedly about being the most appropriate stewards of the land.

“There was a big concerted effort to say they were cleaning up the place,” Mr. Holm said. Nothing could be further from the truth.”

He estimated that the occupation had already cost $6.1 million. The full cost of the cleanup, he said, “is still a moving figure.”