The largest population an area can support with its resources (i.e. food, water, land) is called itscarrying capacity (capacity=amount). If we refer back to the limiting factor of food and water, where the bears each need 10 fish a day to survive and the nearby river can only supply 100 fish per day, the carrying capacity of the bear’s habitat would be 10 bears (Any more than that would require more fish than the river could provide and the bears would starve). A population usually stays near its carrying capacity because of the limiting factors of a habitat.
As a population first begins to grow, it will typically exhibit exponential growth, and it will continue growing until the population overshoots the carrying capacity. The population will then run out of resources and decline rapidly until it can recover and stabilize around the carrying capacity. Rabbit populations exhibited this behavior when they were first introduced into Australia in the mid1800s. At first, their numbers increased rapidly because they had plenty of vegetation to eat and no predators. The rabbits quickly ate the land bare and their population crashed as they starved to death. However, over time, the vegetation recovered, and the rabbit population increased again. The population continues to increase and decrease, but less dramatically.