Croll Et Al

Multiple Choice

Croll et al. studied the effects that long-term inhabitation of artic foxes had on the ecosystems of the Aleutian Islands. Based on their findings, which of the following statements is true?

A) Accumulation of guano on the island was not influenced by the introduction and long-term inhabitation of artic foxes.
B) The nitrogen content in the seabirds' guano increased in response to predation.
C) A reduction in the quantity of guano released on the islands inhabited by artic foxes resulted in an ecological shift from grasslands to more shrubs and forbs.
D) Croll et al. concluded that while artic foxes reduced the number of seabirds on the islands, they did not cause the alteration of island ecosystems where they lived.