As Allan Savory continued researching and studying animal movement and behavior in the presence and absence of predators he was puzzled. Why did some areas that had been grazed and trampled by large herds of animals seemed to deteriorate, while others seemed to improve?

His research led him to the work of French scientist and author, André Voisin, which provided an important missing bit of information: if animals remained in one place too long, or if they returned to it too soon, plants would be overgrazed.

Fourth Key Insight: Timing of grazing is critical to maintaining plant health

Following a grazing, plants use energy from their roots to produce new leaves. Thus, if even one animal remains long enough for a plant to be bitten again while it is growing from root energy, the plant will be overgrazed. And if that one animal returns and bites that plant again, before its roots have recovered, the plant will be overgrazed. What this means is that overgrazing happens one plant at a time. You cannot overgraze land, you can only overgraze plants. In fact, when livestock are improperly managed or the predator-prey connection is disrupted we often find over-rested plants right next to overgrazed plants.