No increase in grass mortality. No differences in species diversity. There is no detectable decrease in soil moisture or increase in soil erosion attributable to herbivory. A truly overgrazed rangeland would exhibit downward trend in most, if not all of these indicators of rangeland health. The explanation for these findings is that native species use the landscape differently than domestic animals.
Native species browse shrubs and grasses heavily in the winter when plants are dormant.
Ungulates then migrate with green up of plants, seldom grazing or browsing a plant more than once in a single season. In summer when grazing effects are most damaging to growing plants, ungulates are widely dispersed. Similarly, trampling of soils, and streambanks are less damaging in winter when snow and frozen soils limits impacts. Finally, natural periodic population reduction due to drought, fires, heavy snow, and predators means that native ungulate numbers are occasionally reduced sometimes significantly, as in this winter. There is no denying that elk and other wildlife have influenced the park's rangelands, but this is no different than finding that fires have changed the age and structure of it's forests, or that wolves and other predators affect the age and structure of prey populations.