So apparently Bundy is claiming that federal lands somehow passed to the ownership of the state of Nevada upon statehood.
Further, because his use of the federally owned land predates the creation of the BLM, he doesn’t feel he is subject to its regulations.

“My forefathers have been up and down the Virgin Valley ever since 1877. All these rights I claim have been created through pre-emptive rights and beneficial use of the forage and the water. I have been here longer. My rights are before the BLM even existed,” Bundy told the station…

…”The federal government has seized Nevada’s sovereignty … they have seized Nevada’s laws and our public land. We have no access to our public land and that is only a little bit of it,” he said.

An interesting legal theory, but one the courts haven’t accepted. Ever.
“I’ve been driving this car since before the speed limit was lowered here. Therefore, I’m not subject to the current speed limit.”