Scientists have noted a decline in fungi species dating back to the early 1900s. Annual crops of edible mushrooms in France and Germany have declined since 1950. One hypothesis to explain this decline is that edible fungi are being overharvested. Global warming and air pollution have also been considered as contributing to the decline. Which of the following would exclude overharvesting as the cause of the decline?

Question

A) Similar declines among edible North American species
B) Fungal-population increases in tropical regions
C) High fungal numbers in nitrogen-poor soils
D) A parallel decline in non-edible species

Answer 1

To exclude overharvesting as the cause of the decline in fungi species, we would look for evidence that could suggest factors other than human harvesting are affecting the populations.

The best answer in this context is:

D) A parallel decline in non-edible species.

If non-edible fungi are also declining, it would suggest that the decline is possibly due to environmental factors (such as global warming or air pollution) rather than solely due to overharvesting of edible species, since non-edible fungi are not harvested by humans.

The other options do not effectively provide evidence against overharvesting:

• A) Similar declines among edible North American species could suggest that overharvesting is a more widespread issue.
• B) Fungal-population increases in tropical regions do not necessarily negate the possibility of overharvesting affecting populations in Europe.
• C) High fungal numbers in nitrogen-poor soils do not provide direct evidence against the hypothesis of overharvesting.

Thus, option D is the best choice that would exclude overharvesting as a cause of the decline.