A five-year exclosure experiment (2002-2007) was conducted.  Three exclosure treatments were applied: (1) open to all herbivores, (2) exclusion of large herbivores, and (3) exclusion of large herbivores and jack rabbits (Lepus californicus).  Some of the parameters measured included plant species frequency and density, winterfat production and seed viability, soil nutrients, soil aggregate stability, and many other variables. We hypothesized that exclusion of grazing from both small and large herbivores would allow both soil and winterfat conditions to improve.  We also hypothesized that soil pH would be a primary factor influencing the trajectory of the vegetative community.  Our hypotheses were framed within the context of state-and-transition models.  One of our proposed state-and-transition models suggests that as grazing disturbance (herbivory and soil disturbance) increases the vegetative community transitions from a winterfat and saltbush (Atriplex nuttallii) dominated community (State 1) to a saltbush and squirreltail (Elymus elymoides) dominated community (State 2) and then finally to an annual weed dominated community (State 3).  Data collection will be completed in October of 2007.  Preliminary findings as well as information on model thresholds, triggers, and feedbacks will be presented.