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

Abstract

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.