“In essence, the federal regulators have opened the door for developers and landowners to destroy habitat suitable for listed species without needing to get a ‘take’ permit,” Sivas said. Courts, not agencies, will now have the final say on what “harm” means going forward.

“Most listed species are at risk of habitat loss, which is frequently the primary basis for the listing decision,” Sivas said.

Species like the Northern Spotted Owl, which depends on old-growth forest, and wide-ranging carnivores like the gray wolf and Canada lynx, whose survival depends on large, connected habitat, will be harder to legally protect now, according to Sivas.

The new rule is facing lawsuits arguing regulators failed to justify the change or comply with environmental review requirements. Courts may ultimately decide what “harm” means case by case. But litigation takes years, and in the meantime, habitat can legally be destroyed, according to Sivas. “Without habitat, there are no wild species,” Sivas said. “That’s a future none of us should want to live in.”