Question

Researchers studying the impact of non-native plant species on local ecosystems observed that in areas where the non-native A. tuberosum was introduced, local plant diversity initially increased. However, over a five-year period, as A. tuberosum became dominant, the overall diversity of native plant species dropped significantly below the original, pre-introduction levels.
Which finding, if true, would best support the researchers' conclusion regarding the long-term impact of A. tuberosum?
A) Native pollinators were found to prefer the nectar of A. tuberosum over that of local plants.
B) The total biomass of the ecosystem remained the same despite the change in species composition.
C) Areas with the highest concentration of A. tuberosum showed the lowest number of unique native plant species.
D) A. tuberosum was able to grow in soil conditions that were previously considered unfavorable for native plants.

Answer 1

C

Reason: C directly links higher A. tuberosum dominance to fewer unique native plant species, supporting the conclusion that the non-native's long-term dominance reduces native diversity. The other options are either indirect (A, D) or unrelated to species richness (B).