Ecologist Dr. Asante hypothesizes that elephant herds in a savanna ecosystem maintain biodiversity by knocking down trees, preventing forest from overtaking grasslands. A competing view holds that periodic fires, not elephants, are the main driver of biodiversity in this system.
Which finding from a long-term study, if true, would most strongly support Dr. Asante's hypothesis over the competing view?
- A
Elephant populations have declined in several African countries due to poaching.
- Bcheck_circle
In areas where elephants were excluded but fires continued at historical frequency, tree cover increased and grassland-dependent species declined.
- C
Both elephants and fires have been part of the savanna ecosystem for thousands of years.
- D
Some grassland species can also persist in lightly forested areas.
Explanation
A controls for fire and isolates elephants' contribution: without elephants, grasslands deteriorate, supporting Asante's hypothesis. B is general background; C and D are tangential.