This is strongly supported. We know that most forests are fragmented, and that fragmented forests require intervention to maintain all their plant and animal species. This lets us infer that if no one intervenes, most forests will lose at least some species.

This is not supported. We know that the survival of at least some endangered species requires intervention in at least some forests. But that definitely doesn’t tell us that we need intervention in most of the world’s forests to keep endangered species alive.

This is not supported. The stimulus never sets out losing species as a sufficient condition for a fragmented forest to fail to sustain itself. Instead, we just get two facts: fragmented forests can’t sustain themselves long-term, and will lose species without intervention.

This is not supported. The stimulus tells us about fragmented forests, not about complete and functional forests. We have no idea if complete forests can maintain all their plant and animal species, or under what conditions that would be possible.

This is not supported. The facts above don’t indicate whether resource managers currently actually intervene in fragmented forests at all. We just don’t know.