“In Bundy’s case the designation of his grazing area as a critical habitat for the endangered desert tortoise gave the BLM the rationale they needed to order a 500% decrease in his cattle numbers. There never was any scientific proof that cattle had historically harmed the desert tortoise.”
They do not need any scientific proof at all. They are invoking Item 15 of The Rio Declaration of Agenda 21:
Principle 15. Precautionary principle
“In order to protect the environment, the precautionary approach shall be widely applied by States according to their capabilities. Where there are threats of serious or irreversible damage, lack of full scientific certainty shall not be used as a reason for postponing cost-effective measures to prevent environmental degradation”
Well, it certainly wasn’t cost effective to Bundy.