Recommend potential study sites in different riparian habitats that could be used to carry out field experiments. Published and unpublished data regarding the impact of both livestock and wildlife grazing on water quality and riparian habitat were summarized. There are numerous reports that summarize impacts of livestock grazing on water quality, but few reports address the impacts of wild ungulates on water quality. The major non-point source pollutants that result from ungulate grazing are sediment, bacteria, and nutrients. Sedimentation is generally the most detrimental non-point source pollutant, whereas increased bacteria levels and nutrient loads from grazing may not have the far reaching impact on the stream ecosystem as sedimentation does.
Results vary on water quality impacts related to livestock densities.
Low densities generally yield little impact to riparian zones and water quality. Light to moderate densities yield variable results in the degree of water quality or riparian zone impacts. Several studies found that moderate to heavy densities resulted in measurable non-point source pollution. Physical and behavioral characteristics of elk heighten the likelihood that they may cause impacts to water quality and riparian areas in Wyoming. Published and unpublished data were summarized to evaluate the potential for the development of predictive models of the relationship of herd levels to non-point source pollution.