Is this a participial phrase or a non-defining phrase? I don't know if there is any distinction between the two, but I was brainwashed by the difference presented by many grammar books. What does it exactly mean in the following? I think 1 is correct.
1. They are a threatened species, (which is) protected by Endangered Species Act - non-defining phrase
2. They are a threatened species, (while they are) protected by Endangered Species Act - participial phrase(simultaneous action or state)

ex)Grizzly bears are a very important part of our wilderness. When they disappear, other species will follow. They are a threatened species, protected by the Endangered Species Act...