Question 108·Hard·Inferences
A 2021 study of satellite and drone imagery of Cameroon’s Korup National Park shows that although annual rainfall has increased over the past three decades, the number of large canopy gaps created by windstorms has almost doubled. The researchers argue that every new gap exposes surrounding trees to greater wind stress, making additional gaps more likely and thereby accelerating forest turnover. They conclude that this self-reinforcing process, rather than localized illegal logging, best explains the unexpectedly rapid shift in tree-species composition now occurring in the park. If the researchers’ conclusion is correct, conservationists who wish to maintain Korup’s present mix of species would do best to ______
Which choice most logically completes the text?
For SAT "Which choice most logically completes the text?" questions, identify the author’s stated conclusion immediately before the blank and treat it as the key premise. Then match the completion to both (1) the conclusion’s claimed cause and (2) the goal stated in the question (here, maintaining the current species mix). Eliminate choices that target a factor the text downplays, that misidentify the causal driver, or that would themselves change what the question says should be maintained.
Hints
Locate the key conclusion
Reread the part starting with "They conclude that..." What do the researchers say is the main reason for the rapid shift in tree species?
Connect the cause to the goal
The conservationists want to maintain the current mix of species. If the researchers are right about the cause, what kind of problem do the conservationists need to address to reach that goal?
Use the contrast with logging
The passage contrasts the self-reinforcing windstorm process with "localized illegal logging." Which answer choice fits with the idea that logging is not the primary driver of the problem?
Check for unintended consequences
Eliminate any answer choices that would themselves significantly change the species mix or that fail to act on the main process described in the study.
Step-by-step Explanation
Identify the researchers’ main conclusion about the cause
Focus on the sentence beginning "They conclude that this self-reinforcing process...":
- The "self-reinforcing process" is the cycle where windstorms create canopy gaps, which then expose more trees to wind, causing even more gaps.
- The researchers say this process, rather than localized illegal logging, best explains the rapid shift in tree-species composition.
So, in their view, windstorm-created canopy gaps are the main driver of the unexpected changes in tree species.
Clarify the goal of the conservationists
The question asks what conservationists who wish to maintain Korup’s present mix of species should do if the researchers’ conclusion is correct.
That means:
- The goal is to keep the current combination of species (prevent further rapid change).
- Their actions should be based on the idea that wind-driven canopy gaps—not logging—are causing the problem.
Infer the type of action that best addresses the cause
If the main cause of the rapid species shift is the increasing number of large canopy gaps created by windstorms, then the most logical conservation strategy is to:
- Reduce or interrupt that wind-driven gap-creation cycle.
- Avoid strategies that primarily target logging (since the researchers say logging is not the main cause).
- Avoid strategies that would themselves reshape the species mix, because the goal is to maintain the current mix.
Match the inference to the answer choices
Now compare each option to the needed strategy:
- The best completion must directly aim to limit the windstorm-driven creation of large canopy gaps.
- It should also support preserving the existing mix of species.
Choice B fits: it proposes reducing the formation of large wind-created canopy gaps, for instance by creating vegetated buffer zones along prevailing-wind corridors.
Therefore, the correct answer is: focus on reducing the formation of large wind-created canopy gaps, perhaps by establishing vegetated buffer zones along prevailing-wind corridors.