Final answer:
The arc-crested dove population experienced an increase in food availability due to a decrease in predator population.
Step-by-step explanation:
The change that occurred in the environment of the arc-crested dove population was an increase in food availability due to a decrease in predator population. This led to an increase in the dove population. As a result, there was a higher competition for resources among the doves, which could potentially impact their survival and reproduction rates.