Technical Abstract: State-and-transition models are being used to describe the coupled plant-soil dynamics in ecological site descriptions. Major challenges in producing these models include 1) distinguishing transient dynamics from changes persistent (and significant) enough to qualify as 'transitions' as recently defined; 2) distinguishing true, self-reinforcing transitions from 'pseudo-transitions' caused by persistent perturbation of a system due to continuous heavy grazing, for example, and that will return to the original state once the perturbation ceases; and 3) isolating present-day spatial heterogeneity within ecological sites that is attributable to transient or threshold dynamics from static patterns caused by differences among the soils grouped within ecological sites. If we are to foster a science-based understanding of rangeland ecosystems using ESDs, we must carefully consider how we treat these phenomena in models. We briefly review these challenges.