Impacts of Wild Horses, Cattle, and Wildlife on Riparian Areas in Idaho

On the Ground • Our study confirms that grazing by cattle and horses can negatively impact riparian ecosystems if not properly managed. • Population levels and grazing patterns of wild free-roaming horses limit management options, potentially leading to rangeland and riparian degradation. • Grazing by wild free-roaming horses and cattle in riparian areas caused streambank disturbance and reductions in stubble height and herbaceous biomass. • Both wild free-roaming horses and cattle affected riparian attributes while wildlife had little effect. • Horses had a greater negative impact than did cattle when examined on an individual animal basis. • Managers and ranchers in areas with wild free-roaming horses will need to consider potential impacts of unmanaged wild free-roaming horses in combination with livestock to mitigate the cumulative effects of multiple species of grazers on riparian condition.