Forester: The great majority of the forests remaining in the world are only sickly fragments of the fully functioning ecosystems they once were. These fragmented forest ecosystems have typically lost their ability to sustain themselves in the long term, yet they include the last refuges for some of the world’s most endangered species. To maintain its full complement of plant and animal species, a fragmented forest requires regular interventions by resource managers.
Summary
The forester says that most forests are currently fragmented and sickly. Fragmented forests usually can’t stay alive long-term. However, some fragmented forests are the only habitat for endangered species. Finally, to keep all the plants and animals in a fragmented forest alive, the forest needs regular interventions by resource managers.
Strongly Supported Conclusions
These facts support the following conclusions:
At least some fragmented forests used to have the ability to sustain themselves long-term.
Most forests will lose plant or animal species without regular interventions by resource managers.
Regular interventions by resource managers are required to protect some of the world’s most endangered species.
A
Most of the world’s forests will lose at least some of their plant or animal species if no one intervenes.
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.
B
Unless resource managers regularly intervene in most of the world’s remaining forests, many of the world’s most endangered species will not survive.
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.
C
A fragmented forest ecosystem cannot sustain itself in the long term if it loses any of its plant or animal species.
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.
D
A complete, fully functioning forest ecosystem can always maintain its full complement of plant and animal species even without interventions by resource managers.
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.
E
At present, resource managers intervene regularly in only some of the world’s fragmented forest ecosystems.
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.