If you ask most people what constitutes overgrazing, they will tell you, "putting too many animals on the land." While that's not totally incorrect, it is misleading.

The reality is that it's possible to overgraze with only one animal. Having more animals will accelerate overgrazing; but overgrazing is not so much how many animals are present, but how those animals are managed.

What constitutes overgrazing is failure to move or rotate animals in harmony with forage growth. Proper grazing management is a matter of moving animals before they have the opportunity to regraze lush regrowth.

It used to be the "proper" stocking rate was determined by percentage utilization. (Unfortunately, this is still used in some government-controlled grazing management situations.) The goal was/is for range managers to determine how many animals it takes to reach that level of utilization. If you exceed that rate you are overgrazing; under that rate, you are not.

Unfortunately, that concept is fundamentally flawed. Grazing animals don't utilize a percentage of any given forage. They will eat palatable grasses down to the ground, while unpalatable plants are left untouched.

This concept (percentage utilization) will slow the amount or intensity of overgrazing, but it still permits damage to the more palatable and nutritious species. Similarly, it used to be believed that given the "proper" stocking rate, animals could continually graze in one pasture.

Not true. Continuous grazing ensures that the higher quality forage in a pasture will be stressed. If stocking rate is light, the changes in forage composition will occur gradually over time. If grazing pressure is light enough, the changes may be so gradual as not to be noticed and/or blamed on other factors (weather patterns, etc.).

It also used to be thought that grazing management was an art. Through experience and perception a manager would intuitively know the "proper" stocking rate. While experience is a valuable tool in grazing management, for the most part it is based on straightforward science.