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Carrying
Capacity
There is a limit to how many animals can live in a particular
area. That limit is called the habitat’s carrying
capacity. The quantity and quality of food, water,
cover, and space determine the carrying capacity of an area. If
one basic requirement is in short supply, it becomes a limiting
factor, and the carrying capacity is lowered. A manager
can increase the habitat’s carrying capacity by adding
or increasing the missing ingredient.
Carrying capacity varies from year to year and from season to season. It
is usually greatest from late spring through fall, because this is when most
young are born and grow. With the coming of winter or a summer drought,
food and cover gradually diminish, as does the habitat’s carrying capacity.
In a stable population, more animals are produced each year than will survive
to the next. Surplus animals are generally lost to starvation, disease,
and/or predation. Young wildlife and animals in poor health experience
the highest death rates. Harvesting game or fish for human consumption
is one way to use the surplus.
The obvious way to increase the number of animals in a population is to increase
the number born and reduce the number that die. However, if a habitat cannot
support any more animals, those efforts will fail. A long-term increase
in population can be accomplished only by increasing the habitat’s carrying
capacity. The carrying capacity is increased and predictably more wildlife
will survive by improving the food, water, cover, and/or space that a wildlife
species needs.
Figure: In theory, the ideal deer population size is slightly below
carrying capacity at point “X” where reproduction and nutritional
requirements are in balance.
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