Are There Two Patterns in a Dry System?

There are two patterns in the system, no one explanation can provide both. Once they observed that there was more than one pattern, they could make better sense of the ecological forces that were driving them. The model predicted that you're going to lose the vegetation in the system in a very predictable manner. If that's the case, and it's always the same progression, then by looking at the pattern, you should be able to tell how healthy your echo system ar.