Bacterial Source Tracking of a Watershed Impacted by Cattle Pastures
Pathogenic microorganisms introduced by cattle may be transported to distant locations via watershed runoff. Escherichia coli, Enterococcus spp., and Streptococcus spp. are a few species present in runoff from land impacted by humans, cattle, and wildlife. Initial data reveals that E. coli concentrations in water are greater in areas impacted by cattle than by humans. And, wildlife contributes greater concentration fluctuations than either humans or cattle. When cattle are removed from a pasture, the bacterial concentrations rapidly decrease; however, slight variations in cattle herd size do not appear to significantly influence these counts. Amplified fragment length polymorphisms (AFLP) and repeated-sequence polymerase chain reactions (rep-PCR) are molecular techniques used in this study to assess the impact of several cattle pastures on one rural communities? watershed system. DNA fingerprints, along with data plots, reveal a direct link between cattle load and bacterial concentrations, as well as seasonal trends, possibly due to migratory wildlife.