Overshoot (L60)

Imagine a community with the following 5 trophic levels: plants, crickets, mice, snakes, and hawks. Predict would happen if more hawks entered the community through immigration. Explain your reasoning. You can describe more than one possible outcome if you wish.

One possible result of hawks entering this community through immigration would be that so many come into the habitat, that the hawks actually overshoot. This means that the population of hawks have exceed their community’s ability to sustain them; there are too many hawks in the area. All these hawks in turn would eat more snakes than are normally eaten in the community, causing a great decline in the snakes’s population density. This then would cause a surplus of mice. (Yes, hawks may begin to eat the mice, but for the sake of simplicity I am going to continue the explanation in terms of a food chain rather than a food web.) The mice then would have too high of a population density for the crickets to keep up. This would cause a decline in the cricket’s population density. This could cause overgrowth of plants that crickets normally utilize. Even a slight change in any level of the trophic pyramid will disrupt other levels as well. This is all eventually worked out by something called the feedback loop it looks something like this. (I tried to make a pretty and simple little picture to explain there so you should definitely click that link!)

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