Carrying Capacity (cont.)

You can think of any chunk of habitat as a bucket and the population of a species as water. The top edge of the bucket represents the carrying capacity. Annual reproduction and recruitment is the main input to a population and “fills” the bucket. Small “leaks,” such as predation or starvation, slowly remove animals from the landscape. Wildlife can also immigrate/emigrate from one population to another, but the number of animals entering or exiting a population in this way is generally low on an annual basis.

If wildlife populations are allowed to artificially exceed carrying capacity, there can be extremely detrimental effects for future generations of the species.

For Example

The population of mule deer in the Coconino National Forest is at carrying capacity. AZGFD brings 5,000 mule deer in from Colorado and releases them in the Coconino National Forest.

Deer that are already there…

...will face increased competition for food, water and mating opportunities.

Newly introduced deer may…

...physically displace deer. This could cause more deer to leave the area and expose them to vehicle strikes, predation or starvation

Introduced deer may contribute to a depletion of resources.

This could lead to poor regrowth from trees, shrubs and other plants, having long-term, lasting effects on the carrying capacity.

Summary

While this is an extreme and fictitious example, it highlights the importance of wildlife and land managers to understand the delicate balance that exists in nature.

It is the job of wildlife agencies and land managers to understand the balance of the landscape and to identify the carrying capacity of a habitat. Maintaining populations at or below the carrying capacity allows managers to ensure no damage is done to the animals or their habitat.

Wildlife managers must consider factors such as:

• current habitat conditions,
• breeding populations, and
• recent breeding success.

Historical trends and potential future habitat predictions may also factor into short- and long-term predictions about the carrying capacity.

Luckily, wildlife managers have a variety of common practices at their disposal to keep habitats and wildlife populations in balance.