The effects on water quality of restricting cattle access to a Georgia Piedmont stream

Abstract

Past research on the benefits of excluding cattle from streams has mostly been conducted in the western U.S. in arid regions with low grazing intensity (usually <1 AUM ha -1 ). This study was conducted on a Georgia Piedmont stream bisecting an intensively grazed dairy pasture (4 to 7.5 AUM ha -1 ). Nutrients, fecal coliforms, and the aquatic insect community were sampled before and after fencing was installed to restrict stream access. Restricting access resulted in decreases in nutrients (17 to 72%, p<0.05) and fecal coliforms (95%, p<0.1) and an increase in aquatic insect diversity. Coincident with fencing installation was cessation of a severe drought that caused an increase in nutrients (67 to 214%) and fecal coliforms (18%) and a decrease in aquatic insect diversity at an upstream reference site. Opposite trends at the study site suggest the effects of cattle access to streams outweigh those of severe drought.