Imagine that there is an animal community containing five trophic levels: plants, crickets, mice, snakes and hawks. What would happen if there was a drastic increase in the predator’s (the hawk’s) population?
If the hawks were to suddenly double in population size then they would drastically decrease the size of thier prey; that is the shrews and snakes.
Once the populations of the mice and reptiles are reduced, the crickets will begin to grow in numbers because their predators are not as many. The crickets will begin to eat the grass at an excessive rate, which will harm the plants and grass growing there. Pretty soon, the plants will be sparse and the crickets will run out of their food supply.
If this continues, and the mice and reptiles never recover their numbers, the crickets will begin to die because of the lack of food. When the crickets die, the snakes and mice will no longer have a food supply, and they too will begin to die off. Once the hawk’s predators are gone, they will no longer have a source of food, and so they will also begin to decline in population.
This just goes to show how important the roles of predators and prey play in the wild. If it weren’t for these trophic levels, than the environment would never be a very stable place.