Think about the example of the food chain, when the snake population grew out of control. Imagine the opposite. Imagine that there was a bounty on snakes and people were allowed to kill them and turn them into their local sheriff for a reward. What would happen in the food chain then?

The primary consumers like rabbits or other small animals that are normally eaten by the secondary consumers (snakes) would over populate and eat all of the producers (plants) and the plants would die out. This would eventually lead to the decrease of the primary consumer (rabbit/small animals) population.